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## **Meet the editor**

Dr Teang Shui Lee is a professor of Water Resources Engineering at the Department of Agricultural and Biological Engineering, Faculty of Engineering, Universiti Putra Malaysia. He holds a BSc in Agricultural Engineering (Water Resources Engineering) from the University of Canterbury, New Zealand, an MSc in Irrigation and Drainage Engineering from Utah State

University, United States of America, and a PhD in Structural Engineering from Universiti Putra Malaysia. Upon graduating, he worked as an assistant engineer with the then Water & Soil Division of the Ministry of Works and Development, Christchurch, New Zealand, for a year, involved with the irrigation schemes of the Canterbury Plains. Dr Lee is a member of the Board of Engineers Malaysia (2009-2012) and Board of Quantity Surveyors Malaysia (2011-2013), and is also the Honorary Secretary of the Institution of Engineers Malaysia (2010-2012). He is a registered professional engineer in Malaysia.

Contents

**Preface IX**

Chapter 1 **Water Quality at the**

Chapter 3 **Provision of Essential**

Chapter 2 **Effluent Quality Parameters**

**Part 1 Reuse Water Quality, Soils and Pollution 1**

**for Safe use in Agriculture 23**  Hamid Iqbal Tak, Akhtar Inam, Yahya Bakhtiyar and Arif Inam

**Minerals Through Foliar Sprays 37**  Rizwana Jabeen and Rafiq Ahmad

**Agriculture at Winder, Balochistan, Pakistan 73**  Shahid Naseem, Salma Hamza and Erum Bashir

Chapter 4 **Assessment of Geochemistry of Soils for**

Roberto Wagner Lourenço,

**Part 2 Managing Irrigation of Crops 111**

and Ricardo Enrique Bressan-Smith

Chapter 6 **Developing Crop-Specific Irrigation**

Chapter 5 **Geospatial Relationships Between Morbidity**

**and Soil Pollution at Cubatão, Brazil 95**

Admilson Irio Ribeiro, Maria Rita Donalisio, Ricardo Cordeiro, André Juliano Franco and Paulo Milton Barbosa Landim

**Management Strategies Considering Effects of Drought on Carbon Metabolism in Plants 113**  Silvia Aparecida Martim, Arnoldo Rocha Façanha

**Cárdenas-Comalcalco Basin, México 3**  Ángel Galmiche-Tejeda, José Jesús Obrador-Olán, Eustolia García-López and Eugenio Carrillo Ávila

### Contents

#### **Preface XI**

	- **Part 2 Managing Irrigation of Crops 111**

X Contents

	- **Part 3 Examples of Irrigation Systems 169**

### Preface

This book, Water Quality, Soil and Managing Irrigation of Crops, consists of twelve chapters written by experts in various disciplines covering topics regarding quality of water for re-use in agriculture, plant agronomy, soils and its properties, health issues pertaining to soil pollution, infiltration, as well as irrigation systems. Chemical and biochemical properties of water in water bodies are indeed important for water ecosystems management. Guidelines for quality of water for re-use in irrigated agriculture are important not only for the short-term measure of replenishing much needed water resources for plants, but suffice to say, that the long term use of such waters, if not carefully handled, can lead to permanent destruction of good agricultural land and may further aggravate water conditions of water bodies and wetlands downstream, where an environmental disaster is waiting to accumulate and recovery may be too difficult thereafter. Thus, for those involved with irrigation and drainage engineering practices, the totality of provision of prudent water resources and soil management is the order of the day if no detrimental after-effects are to surface. Development of appropriate irrigation management strategies in order to produce crops of high quality without wastage of water is the way forward in our future world wherein global warming is a foregone conclusion. Consequent to it may be floods and droughts that seemingly do not follow historical patterns and thus are difficult to cope with. With more than 70% of the water resources going to agriculture and where more than 40% of global food is produced on irrigated soils, it would be a disastrous scenario where too much water unexpectedly washes away much needed crops whilst the onset of unexpected droughts will play havoc with no way out. Another aspect that has been the focus of many researches is the introduction of salt-tolerant varieties of crops. This is particularly so in areas where the accumulation of salts in precious soils is beginning to take its toll on crops. This incremental accumulation of salt concentration through use and re-use of saline waters is building up salinity levels to the extent of eventually rendering the land irrevocable. This is also evident in many areas where seawater saline intrusion occurs and the fresh saline interface keeps encroaching higher up the water table. But such use and re-use of saline waters is the only way that crops can be irrigated, and thus a vicious cycle repeats. Although the growing of crops out of thin air and with irrigation (aeroponics) is possible and hydroponics technology has been established, these technologies are reserved for growing expensive crops as well as in small scale production in view of the high energy costs involved. Therefore, to grow stable food crops in tonnage appropriate to the demands for the masses, we may have to develop drought-resistant crops that can grow with high productivity in poorer soils and environment and less water, but also having the taste and texture that at least is considered passable by the populace.

Water problems in many parts of the world are chronic and without a crackdown on waste, will ultimately worsen as demand for food rises and the vagaries of climate change intensify. Many daunting challenges lie ahead, including providing clean water and sanitation, feeding a world population that is set to rise from 7 billion to 9 billion by 2050 and coping with the impacts of global warming. Pressure for freshwater is rising, from the expanding needs of agriculture, food production and energy consumption to pollution and the weaknesses of water management. Climate change is a real and growing threat and unless humankind can deal with the onslaught or have timely controls of the emissions of global warming gases in place, this phenomenon will not self-diminish but will rather aggravate into a potentially harder one to cope with, temporarily or spatially. Without the benefits of good planning and adaptation, hundreds of millions of people are at risk of hunger, diseases, energy shortages, etc. The spotlight is on the competition for water between cities, farmers and ecosystems, and between countries as well. The water rights issue is set to trouble many adjacent countries. It is estimated that 148 countries have international water basins within their territory and 21 countries actually lie entirely within them. The challenges in accessing water are therefore real and could probably make or break a country. With temperatures arising in almost all the continents over the last decades, the demand and competition for water will be greater, not only for potable water, overcoming droughts in agriculture, but also needed for other demands like firefighting etc. With global warming, it is not impossible that droughts and floods occurring within a short time span of each other or within short distance apart, like what had happened recently in Australia where it has been recorded as getting hotter by the year, and like the unusual big floods that inundated rice fields and the city of Bangkok at the end of 2011. Thus, for the agricultural engineer engaged with irrigation and drainage, the task is ever more daunting and the need to grasp knowledge to deal with all the possible water scenarios is never more demanding. From seeking more efficient and energy effective systems to nurture crops, to seeking solutions with water re-use, the irrigation scientist and specialist will really have a lot at hand.

#### **Dr. Teang Shui Lee**

Professor of Water Resources Engineering, Department of Agricultural and Biological Engineering, Faculty of Engineering, Universiti Putra Malaysia Malaysia

## **Part 1**

## **Reuse Water Quality, Soils and Pollution**

**Water Quality at the**

*Colegio de Postgraduados,*

*1Campus Tabasco, 2Campus Campeche,*

*México*

**Cárdenas-Comalcalco Basin, México**

Water is a resource with an economic, social and environmental value. For this reason when decisions concerning water management, analysis and planning are made, the relationships between the economy, society and the environment should be considered. The study of water resources has great importance when it is developed in a basin's geographical frame. A basin is defined as an area in which rainfall flows through a number of different water channels which in the end converge into one major water body. The water flows towards a common point, which forms a hydrographic unit made up of a group of river bed systems, summits and the outlets, whose limits are marked by "watershed lines" (Dourojeanni and

Cárdenas-Comalcalco basin is located in the hydrological region of Tonalá river, and del Carmen-Machona lagoons. It is bordered by the protected wetland areas to the west of the State of Tabasco and also by the mangrove forests located along the edges of the afore

The objectives of this study were to characterize the water bodies and to determine the chemical and biochemical properties of the water from rivers, lakes and artesian wells of the Cardenas-Comalcalco basin. The results are relevant to water ecosystems management policies and planning since it is a prime resource for both the humans and the wild life

The study was carried out in the Cárdenas-Comalcalco basin which belongs to the hydrological region of the Tonalá river, and del Carmen-Machona lagoons, located in western Tabasco. It occupies an area of 274 255 ha, situated between the coordinates 17°52´ and 18°39´ latitude north and 93°13´ and 94°00´ longitude west. It covers, totally or partially, four municipalities of state of Tabasco: Huimanguillo, Cárdenas, Comalcalco and Paraíso. The basin has an important hydrological system formed by a number of water bodies such

Jouraviev, 2001; Nebel and Wrigth, 1999; ECLAC, 1997).

**1. Introduction**

mentioned lagoons.

which inhabits the area.

**2. Materials and methods 2.1 Localization of study area**

Ángel Galmiche-Tejeda1, José Jesús Obrador-Olán1, Eustolia García-López1 and Eugenio Carrillo Ávila2

## **Water Quality at the Cárdenas-Comalcalco Basin, México**

Ángel Galmiche-Tejeda1, José Jesús Obrador-Olán1, Eustolia García-López1 and Eugenio Carrillo Ávila2 *Colegio de Postgraduados, 1Campus Tabasco, 2Campus Campeche, México*

#### **1. Introduction**

Water is a resource with an economic, social and environmental value. For this reason when decisions concerning water management, analysis and planning are made, the relationships between the economy, society and the environment should be considered. The study of water resources has great importance when it is developed in a basin's geographical frame.

A basin is defined as an area in which rainfall flows through a number of different water channels which in the end converge into one major water body. The water flows towards a common point, which forms a hydrographic unit made up of a group of river bed systems, summits and the outlets, whose limits are marked by "watershed lines" (Dourojeanni and Jouraviev, 2001; Nebel and Wrigth, 1999; ECLAC, 1997).

Cárdenas-Comalcalco basin is located in the hydrological region of Tonalá river, and del Carmen-Machona lagoons. It is bordered by the protected wetland areas to the west of the State of Tabasco and also by the mangrove forests located along the edges of the afore mentioned lagoons.

The objectives of this study were to characterize the water bodies and to determine the chemical and biochemical properties of the water from rivers, lakes and artesian wells of the Cardenas-Comalcalco basin. The results are relevant to water ecosystems management policies and planning since it is a prime resource for both the humans and the wild life which inhabits the area.

#### **2. Materials and methods**

#### **2.1 Localization of study area**

The study was carried out in the Cárdenas-Comalcalco basin which belongs to the hydrological region of the Tonalá river, and del Carmen-Machona lagoons, located in western Tabasco. It occupies an area of 274 255 ha, situated between the coordinates 17°52´ and 18°39´ latitude north and 93°13´ and 94°00´ longitude west. It covers, totally or partially, four municipalities of state of Tabasco: Huimanguillo, Cárdenas, Comalcalco and Paraíso. The basin has an important hydrological system formed by a number of water bodies such

Water Quality at the Cárdenas-Comalcalco Basin, México 5

KIT (1140-H42) for water bodies samples, and an acrylic Horizontal Alpha bottle 2.2 liters KIT (W1120-G42) for samples in artesian wells (Arce 2007). Water samples were placed in plastic recipients of 2 liters and 90 milliliters, respectively, which were transported to the

The parameters that were analyzed to determine water quality were: **biochemical parameters**: oxygen biochemistry demand (DBO), dissolved oxygen (OD) and total solids; **chemical parameters**: ammonium, nitrates, total chlorine, phosphates, heavy metals: zinc (Zn), vanadium (V), cadmium (Cd), lead (Pb) and nickel (Ni); potential hydrogen (pH), electric conductivity (CE), dissolved salts: potassium (K), calcium (Ca), magnesium (Mg) and sodium (Na); **biological parameters**: fecal coliforms and the total number of

Observations of physical characteristics of the water, such as: depth, turbidity, temperature, color, scent and surrounding vegetation were also carried out. Chemical analyses were carried out with methodology used in the Soil, Waters and Plants Analysis Laboratory, of Colegio de Postgraduados, Campus Tabasco, according to Mexican Official Standards.

In order to save space and for ease of handling, the information in the following tables

A variation was observed in water quality over the various sampling seasons in several of study sites (Table 1). In most of the sampled wells nitrates levels were above 10 mg/L as defined by the Mexican Official Standard (NOM-127-SSA1-1994) as limit for human consumption and general usage of water. The highest levels were detected in the norte season. Zone 8, that covers the towns C-32, C-21, C-15 and Ingenio Benito Juárez, turned out to be the most polluted in the rainy and norte seasons; while in dry season, in the well of the town Gutiérrez Gómez (Z-5) there were recorded 206.8 mg/L of nitrates. This represents the

Nitrates are the main pollutant of underground water in rural areas, especially in those areas dedicated to intensive cattle raising. High levels of nitrates in the water (greater than 10 mg/L) have been known to cause methemoglobinemia known as blue baby illness. Although nitrates levels that affect small children usually do not affect older children and

Nitrates in drinking water, at levels which range from 100 to 200 mg/L affects the population's health in general, because once consumed, they can be transformed into salpenter that, under proper circumstances, it can combine with amines to form

There is no a simple way to eliminate nitrates from water since it can not be evaporated with boiling; in fact, boiling water more than 10 minutes can increase their concentration and, if the water is boiled in aluminum recipients, the nitrate can become saltpeter (National

Nitrate levels found indicates a higher risk of contracting cancer by means of water consumption from artesian wells in the mentioned locations, and risk of contracting

adults, they are indicative of bacterial contamination and pesticides presence.

laboratory in a cooler with ice to maintain a temperature of 4°C, to be analyzed.

coliforms.

**3.1 Wells**

**3. Results, analysis and discussion**

maximum value obtained in the wells.

Research Council, 1995).

nitrosamines, compounds which are carcinogenic.

methemoglobinemia for children of practically the whole basin.

shows only the average and median values obtained in analyses.

as the lagoons El Carmen, La Machona, Redonda, El Cocal, El Paso del Ostión and El Arrastradero. The rivers San Felipe, Naranjeño and Santa Ana are also part of this system.

#### **2.2 Selection of supervision sites**

The hydrological characterization of the basin was carried through the analysis of satellite images and observations in the field, both in land and water ecosystems. The study area was divided into nine subareas, which were assigned a number ordered from west to east and north to south. For the water quality analysis, 57 supervision sites were set. The selection was made according to their representativeness, and previous studies carried out in the area. The sites were distributed as follows: four at Naranjeño river, four at Santa Ana river and four at San Felipe river. Four sites were also established in the lagoons, El Carmen, four at Machona, four at Redonda and four at El Arrastradero. Three sites were established in the lagoon El Cocal, three at El Paso del Ostión and three at Las Palmas. Twenty artesian wells were selected. These were located in places with high urban influence (Figure 1).

Fig. 1. Localization of samplings places in different water bodies of The Cárdenas-Comalcalco basin.

In order to understand the seasonal variations of water quality, samples were taken during the three distinct season of the year: the dry season, during the 'nortes' (windy) season and rainy season, taking two samples of water in each supervisory place, a superficial one and the other at a depth of 1 meter, with a pvc Alpha Horizontal Van Dhorn bottle, of 4.2 liters

KIT (1140-H42) for water bodies samples, and an acrylic Horizontal Alpha bottle 2.2 liters KIT (W1120-G42) for samples in artesian wells (Arce 2007). Water samples were placed in plastic recipients of 2 liters and 90 milliliters, respectively, which were transported to the laboratory in a cooler with ice to maintain a temperature of 4°C, to be analyzed.

The parameters that were analyzed to determine water quality were: **biochemical parameters**: oxygen biochemistry demand (DBO), dissolved oxygen (OD) and total solids; **chemical parameters**: ammonium, nitrates, total chlorine, phosphates, heavy metals: zinc (Zn), vanadium (V), cadmium (Cd), lead (Pb) and nickel (Ni); potential hydrogen (pH), electric conductivity (CE), dissolved salts: potassium (K), calcium (Ca), magnesium (Mg) and sodium (Na); **biological parameters**: fecal coliforms and the total number of coliforms.

Observations of physical characteristics of the water, such as: depth, turbidity, temperature, color, scent and surrounding vegetation were also carried out. Chemical analyses were carried out with methodology used in the Soil, Waters and Plants Analysis Laboratory, of Colegio de Postgraduados, Campus Tabasco, according to Mexican Official Standards.

#### **3. Results, analysis and discussion**

In order to save space and for ease of handling, the information in the following tables shows only the average and median values obtained in analyses.

#### **3.1 Wells**

4 Water Quality, Soil and Managing Irrigation of Crops

as the lagoons El Carmen, La Machona, Redonda, El Cocal, El Paso del Ostión and El Arrastradero. The rivers San Felipe, Naranjeño and Santa Ana are also part of this system.

The hydrological characterization of the basin was carried through the analysis of satellite images and observations in the field, both in land and water ecosystems. The study area was divided into nine subareas, which were assigned a number ordered from west to east and north to south. For the water quality analysis, 57 supervision sites were set. The selection was made according to their representativeness, and previous studies carried out in the area. The sites were distributed as follows: four at Naranjeño river, four at Santa Ana river and four at San Felipe river. Four sites were also established in the lagoons, El Carmen, four at Machona, four at Redonda and four at El Arrastradero. Three sites were established in the lagoon El Cocal, three at El Paso del Ostión and three at Las Palmas. Twenty artesian wells

Zone III

Zone IX

Zone VII

Zone IV

were selected. These were located in places with high urban influence (Figure 1).

Zone II

Fig. 1. Localization of samplings places in different water bodies of The Cárdenas-

In order to understand the seasonal variations of water quality, samples were taken during the three distinct season of the year: the dry season, during the 'nortes' (windy) season and rainy season, taking two samples of water in each supervisory place, a superficial one and the other at a depth of 1 meter, with a pvc Alpha Horizontal Van Dhorn bottle, of 4.2 liters

Zone VI

Zone VIII

**2.2 Selection of supervision sites**

Zone I

Zone V

Comalcalco basin.

A variation was observed in water quality over the various sampling seasons in several of study sites (Table 1). In most of the sampled wells nitrates levels were above 10 mg/L as defined by the Mexican Official Standard (NOM-127-SSA1-1994) as limit for human consumption and general usage of water. The highest levels were detected in the norte season. Zone 8, that covers the towns C-32, C-21, C-15 and Ingenio Benito Juárez, turned out to be the most polluted in the rainy and norte seasons; while in dry season, in the well of the town Gutiérrez Gómez (Z-5) there were recorded 206.8 mg/L of nitrates. This represents the maximum value obtained in the wells.

Nitrates are the main pollutant of underground water in rural areas, especially in those areas dedicated to intensive cattle raising. High levels of nitrates in the water (greater than 10 mg/L) have been known to cause methemoglobinemia known as blue baby illness. Although nitrates levels that affect small children usually do not affect older children and adults, they are indicative of bacterial contamination and pesticides presence.

Nitrates in drinking water, at levels which range from 100 to 200 mg/L affects the population's health in general, because once consumed, they can be transformed into salpenter that, under proper circumstances, it can combine with amines to form nitrosamines, compounds which are carcinogenic.

There is no a simple way to eliminate nitrates from water since it can not be evaporated with boiling; in fact, boiling water more than 10 minutes can increase their concentration and, if the water is boiled in aluminum recipients, the nitrate can become saltpeter (National Research Council, 1995).

Nitrate levels found indicates a higher risk of contracting cancer by means of water consumption from artesian wells in the mentioned locations, and risk of contracting methemoglobinemia for children of practically the whole basin.

Water Quality at the Cárdenas-Comalcalco Basin, México 7

 Turbid OD DBO TotSol Turbid OD DBO TotSol Turbid OD DBO TotSol Limits 5 1000 5 1000 5 1000 NTU mg/L mg/L mg/L NTU mg/L mg/L mg/L NTU mg/L mg/L mg/L Zone 5 Average 1.45 1.81 2.4 302.56 14.36 1.68 0.93 499 27.31 2.01 0.98 318.63 Median 1.24 2 0 198 3.93 1.51 1.09 462 21.37 2.03 0.765 293 Zone 6 Average 8.29 2.94 9.02 448.12 12.11 2.37 1.45 574.88 5.66 3.05 0.82 464 Median 1.95 2.38 12 500 6.74 1.21 1.59 627 5.79 3.49 0.51 463.5 Zone 7 Average 1.44 3.26 7.76 277.05 10.04 3.57 1.24 333.38 21.56 4.083 0.51 233.25 Median 1.21 3.65 8.9 329 6.92 3.43 0.96 346.5 7.5 4.22 0.43 252 Zone 8 Average 1.08 1.04 7.19 340.17 13.56 2.70 0.95 478.5 8.92 2.62 0.83 408.75 Median 0.60 0.91 4.41 348.5 5.86 2.86 0.96 437 6.78 2.61 0.7 412.5 Zone 9 Average 5.77 1.29 3.52 493.5 8.84 1.16 0.70 494.38 6.48 2.05 0.75 364.63 Median 3.3 1.24 3.9 490 3.67 0.715 0.735 559 6.12 1.465 0.89 383.5

Although there were no significant differences related with turbidity between the different towns and season of year, Table 2 is shown, that in general, values were lower in the dry season, while in the rainy and norte seasons several wells surpassed permissible limits of 5 NTU. As outlined in the Mexican Official Standards for Environmental Health (NOM-127-

Season Dry Rain Norte

7 Table 2. Turbidity, dissolved oxygen, oxygen biochemistry demand and total solids values

9 In the rainy season only four wells were within the guidelines established in the standard at 10 the two sampling depths. While in the norte season, that increased to 5, the number of wells 11 with acceptable turbidity, in general, values increased in this season. Only the well Z5-03

13 In the dry season, the median was of 1.55 NTU which is very below the limit of permissible 14 turbidity. However in the wells located in the village Carlos Green (Z-6) and Cañales (Z-9)

16 In rainy season, turbidity was greater, with an average value of 11.78 NTU. The median was 17 set in 5.55, both values surpassed the permissible limit; in this season only water of wells 18 Zona Verde 3 (Z-5), Poblado C-16 (Z-6), Villa Tecolutilla (Z-8) and C-29 (Z-9) had the levels

20 During the norte season turbidity even increased, detecting values of up to 60.6 and 52 NTU 21 in Gutiérrez Gómez (Z-5) and Poblado C-25 (Z-5), respectively. In this case only wells in 22 Zona Verde 3 (Z-5), Poblado C-10 (Z-6), Poblado C-32 and C-21 Ingenio Benito Juárez (Z-8)

23 and Cañales (Z-9) fulfilled the standards of quality over the two sampling depths.

8 in artesian wells of the Cárdenas-Comalcalco basin, Tabasco

19 of turbidity as required by the established norms.

12 located in Zona Verde was within the quality standard in all three seasons.

15 were found to have extremely high values, 27.8 and 14.6 NTU, respectively.

5 SSA1-1994) and for Water Quality for Normal Use and Human Consumption.

6

1 Table 1. Nitrates, Ammonium, Phosphate and Chlorine Average Values in Wells of the five 2 study areas in the Cárdenas-Comalcalco basin, Tabasco.

3 Most of sampled wells maintained ammonium levels below the 0.5 mg/L indicated in the 4 Mexican Official Standard (NOM-127-SSA1-1994) and European Standards for Human 5 Consumption Water (1998).

Within the Mexican, nor the World Health Organization or The European Union Standards there are no limits in reference to phosphorus levels in water for human consumption because phosphates are necessary micro nutrients for the operation of the human body and under normal concentrations found in water they pose no risk to health. In The Ecological Criteria of Water Quality (DOF, December 13 1989) for the protection of wild life is set at a maximum of 0.0059 mg/L of phosphates for fresh water, values that were surpassed in all sites and in all three sampling seasons (there were detected up to 3.36 mg/L).

However, these values do not pose threat for human health, since the minimum recommendation in the human diet is of 800 mg/day and a normal diet provides between 1000 and 2000 mg/day; it has been noted that a higher consumption can cause renal illnesses and osteoporosis (http://www.lenntech.com/Periodic-chart-elements/P-en.htm; consulted on 29/04/08).

In the case of Cl, concentrations were below 15 mg/L that OMS recommends as good for human consumption. However, in accordance with Mexican Standard for Wildlife Protection, in some stations concentrations greater than the permissible maximum level of Cl were detected (0.2-1.5 mg/L).

6

6 Water Quality, Soil and Managing Irrigation of Crops

 Nitrate Amm. Phosph Chlor. Nitrate Amm. Phosph Chlor. Nitrate Amm. Phosph Chlor. Limits 10 0.50 0.0059 15 10 0.50 0.0059 15 10 0.50 0.0059 15

Zone 5 Average 53.35 0 0.45 0.125 29.7 0.225 0.65 0.0625 12.1 0.285 0.59 0.1375 Median 8.8 0 0.4 0 15.4 0.24 0.68 0.1 13.2 0.12 0.56 0.15 Zone 6 Average 11 0.225 0.91 0.1875 17.6 0.255 1.02 0.0375 28.05 0.33 0.71 0.125 Median 11 0.18 0.72 0.1 8.8 0.24 0.88 0 30.8 0.24 0.76 0.1 Zone 7 Average 19.25 0.105 1.88 0.1625 13.75 0.255 0.72 0 22 0.15 1.08 0.1125 Median 8.8 0.12 2.44 0.2 8.8 0.24 0.52 0 22 0.12 0.68 0.1 Zone 8 Average 24.2 0.405 1.17 0.6375 36.3 0.195 0.74 0.025 110.5 0.21 1.8 0.1125 Median 17.6 0.12 1.2 0.2 19.8 0.18 0.44 0 105.6 0.24 1.6 0.1 Zone 9 Average 17.325 0.525 0.6 0.05 3.875 0.1625 5.625 0.1375 44 0.09 0.36 0.0875 Median 15.4 0.6 0.56 0.05 3.5 0.15 5 0 30.8 0.12 0.32 0

1 Table 1. Nitrates, Ammonium, Phosphate and Chlorine Average Values in Wells of the five

3 Most of sampled wells maintained ammonium levels below the 0.5 mg/L indicated in the 4 Mexican Official Standard (NOM-127-SSA1-1994) and European Standards for Human

Within the Mexican, nor the World Health Organization or The European Union Standards there are no limits in reference to phosphorus levels in water for human consumption because phosphates are necessary micro nutrients for the operation of the human body and under normal concentrations found in water they pose no risk to health. In The Ecological Criteria of Water Quality (DOF, December 13 1989) for the protection of wild life is set at a maximum of 0.0059 mg/L of phosphates for fresh water, values that were surpassed in all

However, these values do not pose threat for human health, since the minimum recommendation in the human diet is of 800 mg/day and a normal diet provides between 1000 and 2000 mg/day; it has been noted that a higher consumption can cause renal illnesses and osteoporosis (http://www.lenntech.com/Periodic-chart-elements/P-en.htm;

18 In the case of Cl, concentrations were below 15 mg/L that OMS recommends as good for 19 human consumption. However, in accordance with Mexican Standard for Wildlife 20 Protection, in some stations concentrations greater than the permissible maximum level of

12 sites and in all three sampling seasons (there were detected up to 3.36 mg/L).

Season Dry Rain Norte

mg/L

2 study areas in the Cárdenas-Comalcalco basin, Tabasco.

5 Consumption Water (1998).

17 consulted on 29/04/08).

21 Cl were detected (0.2-1.5 mg/L).

Although there were no significant differences related with turbidity between the different towns and season of year, Table 2 is shown, that in general, values were lower in the dry season, while in the rainy and norte seasons several wells surpassed permissible limits of 5 NTU. As outlined in the Mexican Official Standards for Environmental Health (NOM-127- SSA1-1994) and for Water Quality for Normal Use and Human Consumption.

7 Table 2. Turbidity, dissolved oxygen, oxygen biochemistry demand and total solids values 8 in artesian wells of the Cárdenas-Comalcalco basin, Tabasco

In the rainy season only four wells were within the guidelines established in the standard at the two sampling depths. While in the norte season, that increased to 5, the number of wells with acceptable turbidity, in general, values increased in this season. Only the well Z5-03 located in Zona Verde was within the quality standard in all three seasons.

13 In the dry season, the median was of 1.55 NTU which is very below the limit of permissible 14 turbidity. However in the wells located in the village Carlos Green (Z-6) and Cañales (Z-9) 15 were found to have extremely high values, 27.8 and 14.6 NTU, respectively.

In rainy season, turbidity was greater, with an average value of 11.78 NTU. The median was set in 5.55, both values surpassed the permissible limit; in this season only water of wells Zona Verde 3 (Z-5), Poblado C-16 (Z-6), Villa Tecolutilla (Z-8) and C-29 (Z-9) had the levels of turbidity as required by the established norms.

During the norte season turbidity even increased, detecting values of up to 60.6 and 52 NTU in Gutiérrez Gómez (Z-5) and Poblado C-25 (Z-5), respectively. In this case only wells in Zona Verde 3 (Z-5), Poblado C-10 (Z-6), Poblado C-32 and C-21 Ingenio Benito Juárez (Z-8) and Cañales (Z-9) fulfilled the standards of quality over the two sampling depths.

Water Quality at the Cárdenas-Comalcalco Basin, México 9

The values for total and fecal coliforms in the wells sampled were very high in regards to the limits set by Mexican Official Standard (NOM-127-SSA1-1994) and Water Quality Standards of World Health Organization. They outline safe limits between 0 and up to 2 NMP/100 ml of fecal and total coliforms, in water for human consumption. There were found concentrations of up to 505 NMP/100 ml, and values above of 200 NMP/100 ml were the most common. Only in well of Poblado C-31 (Z-9) were detected values smaller than 100

8 Although high coliforms concentrations were maintained over the three sampling seasons, a 9 considerable decrease was detected in the norte season, when most of sites had 10 concentrations bellow 200 NMP/100 ml. This decrease is attributed to the increasing

Implications of these results for health of basin's population are considerable. Most of coliforms bacteria cause no illnesses; however, its presence in water is important for public health because they can indicate presence of such pathogenic microorganisms as bacteria, virus and protozoa. Illnesses associated to water polluted with these organisms involve

Salts concentrations (Na 8.7 meq L-1), (Mg 8.33 meq L-1) and (Ca 5 meq L-1 17 ) in all wells 18 studied were below established limits; no reference, in the existent legal framework, has 19 been found relating to the maximum K levels in water for human consumption; the other

Season Dry Rain Norte

22 Table 4. Dissolved salts values: potassium, calcium, magnesium and sodium in wells of the

 K Ca Mg Na K Ca Mg Na K Ca Mg Na Limits 5 12.15 460 5 12.15 460 5 12.15 460

Zone 5 Average 0.20 3.16 2.95 5.45 29.7 0.23 0.65 0.06 12.1 0.29 0.59 0.14 Median 0.18 3.02 1.86 5.49 15.4 0.24 0.68 0.1 13.2 0.12 0.56 0.15 Zone 6 Average 0.10 3.47 3.60 5.45 17.6 0.26 1.02 0.04 28.05 0.33 0.71 0.13 Median 0.07 3.36 2.06 5.31 8.8 0.24 0.88 0 30.8 0.24 0.76 0.1 Zone 7 Average 0.11 2.65 1.27 2.53 13.75 0.26 0.72 0 22 0.15 1.08 0.11 Median 0.1 2.69 1.24 1.55 8.8 0.24 0.52 0 22 0.12 0.68 0.1 Zone 8 Average 0.20 3.91 1.88 3.46 36.3 0.20 0.74 0.03 110.5 0.21 1.8 0.11 Median 0.20 4.00 1.77 3 19.8 0.18 0.44 0 105.6 0.24 1.6 0.1 Zone 9 Average 0.035 4.17 3.37 3.57 3.88 0.16 5.63 0.14 44 0.09 0.36 0.09 Median 0.04 4.07 3.50 3.02 3.5 0.15 5 0 30.8 0.12 0.32 0

11 phreatic level during that time. The bacteria are diluted in greater quantity of water.

16 symptoms similar to flu, vomiting, diarrhea and fever (Pontius, 2002).

20 parameters studied were inside the limits allowed (Table 4).

Meq L-1

23 five study areas in the Cárdenas-Comalcalco basin, Tabasco

7 NMP/100 ml in the three samplings.

21

The Average and median values for turbidity, considering all the wells and depths, was 13.99 and 6.44 NTU, respectively, both above the rates found in the established norms. The high turbidity values found are of great concern, since consumption of very muddy waters constitutes a risk factor for human health, since the mud can protect to pathogen organisms of disinfectants effects, besides stimulate bacterial growth and increase chlorine demand. Due to the absorption capacity of some particles, they can have present harmful organic compounds which should not be present in water designated for human consumption (Safe Drinking Water, 1980).

9 There were not found reference values for OD in the consulted standards and references, 10 because concentrations up to saturation point in water have no effect on human health.

However, in Poblado C-10 (Z-6) and Villa Aldama (Z-7) in the dry and rainy seasons there were detected high oxygen values, which suggests that there exists primary productivity in the wells and, consequently, considerable N and P quantities. Although presence of green algae in water does not necessarily affect human health, primary productivity is generally accompanied by an increment in bacterial populations, which can create a series of infections for consumer.

In general pH was between 6.5 and 8, within limit allowed by Mexican Official Standard NOM-127-SSA1-1994, for Water for Human Consumption (Table 3), although in some places the value surpassed 8 in some of the three seasons studied. In one case a location had high pH values in the three samplings.

22 Table 3. pH, electric conductivity (CE), temperature (T°), total (C-T) and fecal (C-F) 23 coliforms values in artesian wells of the Cárdenas-Comalcalco basin, Tabasco.

21

21

8 Water Quality, Soil and Managing Irrigation of Crops

The Average and median values for turbidity, considering all the wells and depths, was 13.99 and 6.44 NTU, respectively, both above the rates found in the established norms. The high turbidity values found are of great concern, since consumption of very muddy waters constitutes a risk factor for human health, since the mud can protect to pathogen organisms of disinfectants effects, besides stimulate bacterial growth and increase chlorine demand. Due to the absorption capacity of some particles, they can have present harmful organic compounds which should not be present in water designated for human consumption (Safe

There were not found reference values for OD in the consulted standards and references, because concentrations up to saturation point in water have no effect on human health. However, in Poblado C-10 (Z-6) and Villa Aldama (Z-7) in the dry and rainy seasons there were detected high oxygen values, which suggests that there exists primary productivity in the wells and, consequently, considerable N and P quantities. Although presence of green algae in water does not necessarily affect human health, primary productivity is generally accompanied by an increment in bacterial populations, which can create a series of

17 In general pH was between 6.5 and 8, within limit allowed by Mexican Official Standard 18 NOM-127-SSA1-1994, for Water for Human Consumption (Table 3), although in some places 19 the value surpassed 8 in some of the three seasons studied. In one case a location had high

Season Dry Rain Norte

22 Table 3. pH, electric conductivity (CE), temperature (T°), total (C-T) and fecal (C-F) 23 coliforms values in artesian wells of the Cárdenas-Comalcalco basin, Tabasco.

 pH CE T° C-T C-F pH CE T° C-T C-F pH CE T° C-T C-F 6.5-8 0 0 6.5-8 0 0 6.5-8 0 0 Zone 5 Average 7.39 0.77 26.15 274.6 266.1 7.84 0.91 27 180.8 173.5 7.66 0.58 27.68 179.5 176.6 Median 7.47 0.38 26.15 297.5 287 7.83 0.84 27 161.5 153.5 7.71 0.53 27.7 142.5 142 Zone 6 Average 7.76 0.79 25.11 209.4 201.8 7.69 1.11 27.4 158 150.8 7.87 0.85 27.9 183.6 178.9 Median 7.84 0.89 25 219.5 210.5 7.73 1.23 27.5 74 72 7.98 0.84 27.8 182 176 Zone 7 Average 7.60 0.54 25.38 187.5 174 7.68 0.61 28 201.9 195.6 7.74 0.43 28.16 126.6 124.5 Median 7.66 0.60 25.45 187 162 7.84 0.63 27.8 166 162.5 7.77 0.46 28.25 120 117 Zone 8 Average 7.72 0.72 26.09 143.5 135.5 6.96 1.71 27.5 165.8 160 7.68 0.74 28.68 130.4 129.9 Median 7.83 0.73 25.95 116 108 7.80 0.81 27.5 97 94 7.61 0.75 29.1 128 128 Zone 9 Average 7.61 0.90 26.04 131.6 125.1 7.51 0.9 27.4 291.3 282.4 7.60 0.66 28.52 99.75 97.8 Median 7.73 0.89 26.25 134.5 131 7.56 1.02 27.4 253.5 248.5 7.61 0.70 28.39 89.5 85 Units. CE: dS m-1; T°: °C; C-T y C-F: NMP/100 mL

8 Drinking Water, 1980).

16 infections for consumer.

21

20 pH values in the three samplings.

The values for total and fecal coliforms in the wells sampled were very high in regards to the limits set by Mexican Official Standard (NOM-127-SSA1-1994) and Water Quality Standards of World Health Organization. They outline safe limits between 0 and up to 2 NMP/100 ml of fecal and total coliforms, in water for human consumption. There were found concentrations of up to 505 NMP/100 ml, and values above of 200 NMP/100 ml were the most common. Only in well of Poblado C-31 (Z-9) were detected values smaller than 100 NMP/100 ml in the three samplings.

Although high coliforms concentrations were maintained over the three sampling seasons, a considerable decrease was detected in the norte season, when most of sites had concentrations bellow 200 NMP/100 ml. This decrease is attributed to the increasing phreatic level during that time. The bacteria are diluted in greater quantity of water.

Implications of these results for health of basin's population are considerable. Most of coliforms bacteria cause no illnesses; however, its presence in water is important for public health because they can indicate presence of such pathogenic microorganisms as bacteria, virus and protozoa. Illnesses associated to water polluted with these organisms involve symptoms similar to flu, vomiting, diarrhea and fever (Pontius, 2002).

Salts concentrations (Na 8.7 meq L-1), (Mg 8.33 meq L-1) and (Ca 5 meq L-1 17 ) in all wells studied were below established limits; no reference, in the existent legal framework, has been found relating to the maximum K levels in water for human consumption; the other parameters studied were inside the limits allowed (Table 4).

22 Table 4. Dissolved salts values: potassium, calcium, magnesium and sodium in wells of the 23 five study areas in the Cárdenas-Comalcalco basin, Tabasco

Water Quality at the Cárdenas-Comalcalco Basin, México 11

Excepting station 1 of The Naranjeño river, and stations 1, 2 and 3 of The San Felipe river which quantities were non-detectable in dry season, the same as for station 3 of The Naranjeño river and station 3 of The Santa Ana river in that of the norte season, in general, in all seasons, very high levels of ammonium were observed. These levels are very superior

Ammonium averages and median were around 0.1 in the dry and norte seasons, while in rainy season they increased dramatically up to an average of 0.435, showing values of up to 2.16 mg/L. Being a toxic compound, its presence at these concentrations will have noxious

The nitrates and ammonium high concentrations effects on aquatic life have not been studied in this basin. However, it is known that their excess causes water acidification, eutrophication and the occurrence of toxic algae, as well as having a toxic action on aquatic animals in the form of gills epithelium damage, which can cause asphyxia, glycolysis stimulation and Krebs cycle suppression that causes acidosis and reduction of blood's oxygen transporting capacity; unpairing oxidative phosphorylation that causes inhibition of ATP production in brain's basilar region; interference of immune system that increases

Practically in all sampling sites and in the three seasons of year phosphates were also superior to the limits allowed in Ecological Criteria of Water Quality (CE-CCA-001/89 12.13.89) for Aquatic Life Protection that is of 0.1 mg/L of total phosphates for rivers and

Only the station 1 of The Santa Ana river showed slightly lower levels (0.08) in dry season.

Phosphate excess is one of main causes of eutrophication of natural water bodies (Ramírez et. al., 2005), but few studies exist on effects that high phosphate concentrations in water can have on aquatic animals, although is known that it can negatively affect mollusks

A progressive increase was detected in residual chlorine levels from the dry season to that of the rainy season. In the first case, only sample station 3 The Santa Ana river had levels above

In the rainy season there were 5 stations that surpassed allowed limits (3 The Naranjeño river, 1 The Santa Ana river and 1 and The San Felipe river). During the norte season all sampling stations practically surpassed limits allowed by Ecological Criteria of Water Quality (CE-CCA-001/89 12.13.89) for Aquatic Life Protection that, for the case of fresh

During in the dry season as well as in that of the rainy season most of sites were inside acceptable turbidity limits for the development of aquatic communities (40 NTU) according to water contamination control (UNESCO, 1995), except for stations 1 The Naranjeño river, station 4 The Santa Ana river and station 4 The San Felipe river that, during the dry season

However, in the norte season, sampling stations of the San Felipe river had highest values, of up to 86 NTU, as well as station 3 of the Naranjeño river, with more than 89 NTU, which surpasses maximum permissible limits. In the rainy season there were the lowest values. Turbidity is caused by the leaching of inorganic fertilizers excessively used in agriculture and by erosion provoked by excesses of human activity in higher lands, such as immoderate

reproduction and fish eggs appearance (Russo, 1985; Reynolds and Guillaume, 1998).

susceptibility to bacterial and parasitic illnesses (Camargo et. al., 2007).

As in the case of nitrates and ammonium, values were lower in dry season.

water it allows concentrations of up to 0.011 mg/L of residual chlorine.

to the maximum tolerance for fish (Table 5).

streams and 0.002 mg/L for marine water.

effects for aquatic life.

standard in two depths.

surpassed these limits.

pruning of forests and mining.

#### **3.2 Rivers**

The obtained results do not show a specific pattern which indicates that any of the rivers have suitable water quality conditions, there were no significant differences in any of the parameters studied neither between rivers and sampling seasons.

Taking as a reference Ecological Criteria of Water Quality (DOF, December 13, 1989) that establish 0.04 mg/L of nitrates, as the maximum permissible for the protection of marine aquatic life, it can be observed that in general, all sampling points were polluted in all three seasons of year. Except for stations 3 and 4 of The Naranjeño river, station 4 of The Santa Ana river and station 4 of The San Felipe river which were below the standards only during the dry season.

In fact, water generally was less polluted by nitrates in dry season (average was in 5.3 and median in 4.4) than in the rainy and norte seasons, when nitrates concentration increased almost twice (Table 5). Evidently, the increase in nitrates concentration coincides with precipitation increase. Also, the study basin is characterized to contain a vast surface of sugar cane cultivation, in which fertilizers and other chemical products are intensively used, some of which are dragged into the rivers by the effects of the rains, causing a marked increase in their concentration in seasons of more pluvial precipitation. <sup>18</sup>

Table 5. Nitrates, ammonium, phosphates and chlorine values in three rivers studied in The Cárdenas-Comalcalco basin, Tabasco.

Similar behavior was detected in ammonium concentration, although in Mexico there is no official standard that makes reference to tolerance limits. The Ecological Criteria of Water Quality (DOF December 13 1989) only considers ammoniacal nitrogen within the listed pollutants, establishing 0.06 mg/L ammonium as maximum permissible for protection of aquatic life (in fresh water). Although some authors (López et. al, no date) have used 0.50 mg/L as maximum reference value, according to standard (NOM-127-SSA1-1994) in this work it was not used because it refers to water for human consumption.

Aquatic animals are more sensitive to ammonium than mammals. If we apply the previously referred limit of 0.50 mg/L, almost all obtained values would be below it, which would disguise the results obtained in relation to effect on aquatic organisms. Therefore, it was decided to take as reference the tolerance limit for fish, of 0.02 mg L-1 of NH3.

The obtained results do not show a specific pattern which indicates that any of the rivers have suitable water quality conditions, there were no significant differences in any of the

Taking as a reference Ecological Criteria of Water Quality (DOF, December 13, 1989) that establish 0.04 mg/L of nitrates, as the maximum permissible for the protection of marine aquatic life, it can be observed that in general, all sampling points were polluted in all three seasons of year. Except for stations 3 and 4 of The Naranjeño river, station 4 of The Santa Ana river and station 4 of The San Felipe river which were below the standards only during

In fact, water generally was less polluted by nitrates in dry season (average was in 5.3 and median in 4.4) than in the rainy and norte seasons, when nitrates concentration increased almost twice (Table 5). Evidently, the increase in nitrates concentration coincides with precipitation increase. Also, the study basin is characterized to contain a vast surface of sugar cane cultivation, in which fertilizers and other chemical products are intensively used, some of which are dragged into the rivers by the effects of the rains, causing a marked

Season Dry Rain Norte

Table 5. Nitrates, ammonium, phosphates and chlorine values in three rivers studied in The

Similar behavior was detected in ammonium concentration, although in Mexico there is no official standard that makes reference to tolerance limits. The Ecological Criteria of Water Quality (DOF December 13 1989) only considers ammoniacal nitrogen within the listed pollutants, establishing 0.06 mg/L ammonium as maximum permissible for protection of aquatic life (in fresh water). Although some authors (López et. al, no date) have used 0.50 mg/L as maximum reference value, according to standard (NOM-127-SSA1-1994) in this

Aquatic animals are more sensitive to ammonium than mammals. If we apply the previously referred limit of 0.50 mg/L, almost all obtained values would be below it, which would disguise the results obtained in relation to effect on aquatic organisms. Therefore, it

work it was not used because it refers to water for human consumption.

was decided to take as reference the tolerance limit for fish, of 0.02 mg L-1 of NH3.

 Nitrate Amm. Phosph Chlor. Nitrate Amm. Phosph Chlor. Nitrate Amm. Phosph Chlor. Limits 0.04 0,02 0.1 0.011 0.04 0,02 0.1 0.011 0.04 0,02 0.1 0.011

Naranjeño river Average 7.15 0.2 0.96 0 7.15 0.24 0.69 0.025 6.05 0.12 0.92 0.1 Median 4.4 0.2 0.28 0 8.8 0.24 0.72 0 6.6 0.12 0.92 0.1 Santa Ana river Average 4.95 0.1625 0.69 0.175 7.7 0.345 1.07 0.375 8.25 0.105 1.24 0.1125 Median 4.4 0.15 0.28 0.05 8.8 0.36 0.96 0 8.8 0.06 1.28 0.1 San Felipe river Average 3.85 0.075 1.31 0.1375 7.15 0.72 1.63 0.1 7.625 0.105 1.02 0.0875 Median 4.4 0 0.6 0 8.8 0.48 1.8 0.1 8.5 0.12 0.84 0.1

parameters studied neither between rivers and sampling seasons.

increase in their concentration in seasons of more pluvial precipitation. <sup>18</sup>

mg/L

Cárdenas-Comalcalco basin, Tabasco.

**3.2 Rivers**

the dry season.

Excepting station 1 of The Naranjeño river, and stations 1, 2 and 3 of The San Felipe river which quantities were non-detectable in dry season, the same as for station 3 of The Naranjeño river and station 3 of The Santa Ana river in that of the norte season, in general, in all seasons, very high levels of ammonium were observed. These levels are very superior to the maximum tolerance for fish (Table 5).

Ammonium averages and median were around 0.1 in the dry and norte seasons, while in rainy season they increased dramatically up to an average of 0.435, showing values of up to 2.16 mg/L. Being a toxic compound, its presence at these concentrations will have noxious effects for aquatic life.

The nitrates and ammonium high concentrations effects on aquatic life have not been studied in this basin. However, it is known that their excess causes water acidification, eutrophication and the occurrence of toxic algae, as well as having a toxic action on aquatic animals in the form of gills epithelium damage, which can cause asphyxia, glycolysis stimulation and Krebs cycle suppression that causes acidosis and reduction of blood's oxygen transporting capacity; unpairing oxidative phosphorylation that causes inhibition of ATP production in brain's basilar region; interference of immune system that increases susceptibility to bacterial and parasitic illnesses (Camargo et. al., 2007).

Practically in all sampling sites and in the three seasons of year phosphates were also superior to the limits allowed in Ecological Criteria of Water Quality (CE-CCA-001/89 12.13.89) for Aquatic Life Protection that is of 0.1 mg/L of total phosphates for rivers and streams and 0.002 mg/L for marine water.

Only the station 1 of The Santa Ana river showed slightly lower levels (0.08) in dry season. As in the case of nitrates and ammonium, values were lower in dry season.

Phosphate excess is one of main causes of eutrophication of natural water bodies (Ramírez et. al., 2005), but few studies exist on effects that high phosphate concentrations in water can have on aquatic animals, although is known that it can negatively affect mollusks reproduction and fish eggs appearance (Russo, 1985; Reynolds and Guillaume, 1998).

A progressive increase was detected in residual chlorine levels from the dry season to that of the rainy season. In the first case, only sample station 3 The Santa Ana river had levels above standard in two depths.

In the rainy season there were 5 stations that surpassed allowed limits (3 The Naranjeño river, 1 The Santa Ana river and 1 and The San Felipe river). During the norte season all sampling stations practically surpassed limits allowed by Ecological Criteria of Water Quality (CE-CCA-001/89 12.13.89) for Aquatic Life Protection that, for the case of fresh water it allows concentrations of up to 0.011 mg/L of residual chlorine.

During in the dry season as well as in that of the rainy season most of sites were inside acceptable turbidity limits for the development of aquatic communities (40 NTU) according to water contamination control (UNESCO, 1995), except for stations 1 The Naranjeño river, station 4 The Santa Ana river and station 4 The San Felipe river that, during the dry season surpassed these limits.

However, in the norte season, sampling stations of the San Felipe river had highest values, of up to 86 NTU, as well as station 3 of the Naranjeño river, with more than 89 NTU, which surpasses maximum permissible limits. In the rainy season there were the lowest values. Turbidity is caused by the leaching of inorganic fertilizers excessively used in agriculture and by erosion provoked by excesses of human activity in higher lands, such as immoderate pruning of forests and mining.

Water Quality at the Cárdenas-Comalcalco Basin, México 13

Base on The Mexican Official Standard (NOM-001-ECOL-1996), water of the sampled sites in all seasons of year is located in permissible maximum limit for biochemical demand of

However, in the dry season values of three stations of the San Felipe river greatly surpasses that level reaching up to 527 mg/L in site 1 at 1 meter deep. This can be due to the fact that the river is located in the margins of some industry or big earth extensions with intensive agricultural activity that discharges a great quantity of organic waste in the system. A factor could also be a decrease in water flowrates limits, its flow being stagnated. When nutrients do not flow the biological activity concentrates. The high levels of ammonium and phosphates are related with a high content of organic matter, these levels usually cause decrease in values of OD and increase in those of DBO, which is what seems to be the case. The above-mentioned can be linked in particular with high indexes of organic decomposition that cause diverse

Total suspended solids were very high in the three sampling seasons, although in dry season this diminished in 5 of 12 stations, especially in those of the Santa Ana river (Table 6). This is attributed to the fact that in the rainy season, the rivers of flood plains of Tabasco drag a great quantity of material from soil coming from the mountains of Chiapas and that ends in Gulf of Mexico. The concentration of total solids in water were dramatically far from what the Mexican Official Standard specifies (NOM-001-ECOL-1996) on Permissible Maximum Limits for Basic Pollutants in Residual Water Discharges, that establishes a maximum of 40 mg/L as a daily average for rivers, because in this case an average of 4277

Most of pH values are within allowed range in the standard for discharges of residual waters (NOM-001-ECOL-1996) that goes from 5 to 10. All sampling sites of the Naranjeño river showed superior values at 8.5 in dry season, probably because of discharges of Ingenio Benito Juárez; in the same season station 1 of The San Felipe river showed acid pH, smaller

Season Dry Rain Norte

Table 7. pH, electric conductivity, temperature, fecal and total coliforms values in the three

 pH CE T° C-T C-F pH CE T° C-T C-F pH CE T° C-T C-F 6.5-8 <200 <200 6.5-8 <200 <200 6.5-8 <200 <200 Río Naranjeño Average 8.65 0.28 27.83 2400.1 2400 7.89 4.71 30.10 95.75 93.25 7.25 1.78 29.73 105.9 104.6 Median 8.89 0.24 27.5 2400 2400 7.92 0.66 29.9 91 89 7.28 0.52 29.65 111 109.5 Río Santa Ana Average 7.49 2.35 28.26 2400. 2400 7.57 12.79 30.5 324.9 299.8 7.39 14.26 27.36 68.25 68 Median 7.43 0.51 28.4 2400 2400 7.60 7.20 30.6 203.5 190.5 7.43 4.67 28.75 66 62.5 Río San Felipe Average 6.64 1.52 25.40 739.84 457.55 7.67 5.87 29.7 223.6 216.6 7.05 2.08 29.15 172 165.9 Median 7.07 0.84 28.85 299.32 132.46 7.59 2.3 29.6 255.5 246.5 7.02 1.65 29.15 184 176 Units. CE: dS m-1; T°: °C; C-T y C-F: NMP/100 mL

oxygen (DBO), set at 60 mg/L as the daily average.

adverse effects on aquatic organisms, particularly on the fish.

was detected in the rainy season and 2634 in that of the norte.

than 6.5 (Table 7).

rivers studied.

The turbidity can cause a decrease in water O2 concentration, with a rising negative effect on fish, and reduction of light penetration in water column, which diminishes rate of photosynthesis activity and, consequently, it reduces the primary productivity of the phytoplankton that is the aquatic animals basic food.

A primary productivity reduction can collapse at superior trophic levels. On the other hand, turbidity could also negatively affect populations of invertebrates and to interfere with behavior, feeding and growth of many fish species and cause damages, due gills abrasion and obstruction; it has also been found that increases the susceptibility of fish to illnesses, since mucous secreted by them in answer to the high concentrations of suspended solids attracts bacteria and mushrooms (Scottish Natural Heritage, 1996).

Regulation for waters contamination prevention and control (DOF, March 29 1973) states that dissolved oxygen (OD) level should never be lower than 5.0 mg/L in waters for recreational use, without primary contact and for the exploitation of fish. This concentration is necessary to guarantee aquatic fauna good development.

In general, there were found levels much below this limit in almost all sampling stations and seasons (Table 6), in the three rivers the highest were detected in the dry season, although the San Felipe river always kept below acceptable levels; in the rainy season the concentration, in general, diminished reaching its lowest level in the norte season. This is contrary to expectation, since as water volume increases, nutrients concentrations trend to diminish which works against algae proliferation. In general, low OD concentrations detected seem to be result of accumulation of nutrients leached from the land by rains, those that promote algae excessive development and system eutrophication. Low OD concentration in water interferes with fish growth and reproduction, increases propensity to illnesses and, in extreme cases, it can cause their death (Shoji, et. al 2005). Studies carried out by Breitburg et al. (1997) demonstrated that low OD concentrations alter trophic nets in natural waters bodies when reducing efficiency of larvae and juvenile fish of escaping from their predators.

Table 6. Turbidity, dissolved oxygen, Oxygen Biochemistry Demand and Total Solids values in three rivers studied in The Cárdenas-Comalcalco basin, Tabasco.

Water Quality, Soil and Managing Irrigation of Crops

The turbidity can cause a decrease in water O2 concentration, with a rising negative effect on fish, and reduction of light penetration in water column, which diminishes rate of photosynthesis activity and, consequently, it reduces the primary productivity of the

A primary productivity reduction can collapse at superior trophic levels. On the other hand, turbidity could also negatively affect populations of invertebrates and to interfere with behavior, feeding and growth of many fish species and cause damages, due gills abrasion and obstruction; it has also been found that increases the susceptibility of fish to illnesses, since mucous secreted by them in answer to the high concentrations of suspended solids

Regulation for waters contamination prevention and control (DOF, March 29 1973) states that dissolved oxygen (OD) level should never be lower than 5.0 mg/L in waters for recreational use, without primary contact and for the exploitation of fish. This concentration

In general, there were found levels much below this limit in almost all sampling stations and seasons (Table 6), in the three rivers the highest were detected in the dry season, although the San Felipe river always kept below acceptable levels; in the rainy season the concentration, in general, diminished reaching its lowest level in the norte season. This is contrary to expectation, since as water volume increases, nutrients concentrations trend to diminish which works against algae proliferation. In general, low OD concentrations detected seem to be result of accumulation of nutrients leached from the land by rains, those that promote algae excessive development and system eutrophication. Low OD concentration in water interferes with fish growth and reproduction, increases propensity to illnesses and, in extreme cases, it can cause their death (Shoji, et. al 2005). Studies carried out by Breitburg et al. (1997) demonstrated that low OD concentrations alter trophic nets in natural waters bodies when reducing efficiency of larvae and juvenile fish of escaping from

Season Dry Rain Norte

Table 6. Turbidity, dissolved oxygen, Oxygen Biochemistry Demand and Total Solids values

in three rivers studied in The Cárdenas-Comalcalco basin, Tabasco.

 Turbid OD DBO SolTot Turbid OD DBO SolTot Turbid OD DBO SolTot Limits 40 5.0 60 40 40 5.0 60 40 40 5.0 60 40 NTU mg/L mg/L mg/L NTU mg/L mg/L mg/L NTU mg/L mg/L mg/L Naranjeño river Average 41.98 5.16 22.79 154.25 14.5 5.24 1.89 2562.9 32.96 2.57 1.13 978.34 Median 17.15 6.245 20.71 59 13.4 5.12 1.86 363 19.30 2.44 1.13 285.5 Santa Ana river Average 25.85 6.16 13.41 45.1 11.01 4.94 1.58 7035.3 20.44 2.77 1.44 5780.6 Median 10.42 6.24 12.20 45 9.37 4.81 1.95 3970 15.75 2.81 1.47 1199 San Felipe river Average 18.06 2.39 122.05 71.5 15.63 1.40 0.89 3233.9 55.04 1.43 1.44 1144.3 Median 15.45 1.275 55.99 54 12.70 0.38 0.53 1263 62.75 1.585 1.56 906.5

phytoplankton that is the aquatic animals basic food.

attracts bacteria and mushrooms (Scottish Natural Heritage, 1996).

is necessary to guarantee aquatic fauna good development.

their predators.

Base on The Mexican Official Standard (NOM-001-ECOL-1996), water of the sampled sites in all seasons of year is located in permissible maximum limit for biochemical demand of oxygen (DBO), set at 60 mg/L as the daily average.

However, in the dry season values of three stations of the San Felipe river greatly surpasses that level reaching up to 527 mg/L in site 1 at 1 meter deep. This can be due to the fact that the river is located in the margins of some industry or big earth extensions with intensive agricultural activity that discharges a great quantity of organic waste in the system. A factor could also be a decrease in water flowrates limits, its flow being stagnated. When nutrients do not flow the biological activity concentrates. The high levels of ammonium and phosphates are related with a high content of organic matter, these levels usually cause decrease in values of OD and increase in those of DBO, which is what seems to be the case. The above-mentioned can be linked in particular with high indexes of organic decomposition that cause diverse adverse effects on aquatic organisms, particularly on the fish.

Total suspended solids were very high in the three sampling seasons, although in dry season this diminished in 5 of 12 stations, especially in those of the Santa Ana river (Table 6). This is attributed to the fact that in the rainy season, the rivers of flood plains of Tabasco drag a great quantity of material from soil coming from the mountains of Chiapas and that ends in Gulf of Mexico. The concentration of total solids in water were dramatically far from what the Mexican Official Standard specifies (NOM-001-ECOL-1996) on Permissible Maximum Limits for Basic Pollutants in Residual Water Discharges, that establishes a maximum of 40 mg/L as a daily average for rivers, because in this case an average of 4277 was detected in the rainy season and 2634 in that of the norte.

Most of pH values are within allowed range in the standard for discharges of residual waters (NOM-001-ECOL-1996) that goes from 5 to 10. All sampling sites of the Naranjeño river showed superior values at 8.5 in dry season, probably because of discharges of Ingenio Benito Juárez; in the same season station 1 of The San Felipe river showed acid pH, smaller than 6.5 (Table 7).

Table 7. pH, electric conductivity, temperature, fecal and total coliforms values in the three rivers studied.

Water Quality at the Cárdenas-Comalcalco Basin, México 15

lagoons surpassed this value during the rainy and norte seasons. In the dry season all lagoons, except for sampling site 3 of El Cocal lagoon, were below the reference value. In most of the sampling sites nitrates were found in non-detectable quantities, however, these increased until surpassing reference value in rain season (Table 9), with concentrations

This trend continued during the norte season, being detected up to 15.4 mg/L in sampling site 1 of Las Palmas lagoon, although on average concentrations were greater in the rainy season, with 8.2 mg/L than in that of the norte (6.6 mg/L). Although there were extreme values, there were also found sites with very low nitrate concentrations such as sites 2 and 3

11 Increase of nitrates quantities during rainy and norte seasons seems to be result of the 12 influence of a greater water volume, rich in nutritious material coming from human 13 activities that the rivers catch; since in dry season entrance of seawater with its tides allows

Season Dry Rain Norte

16 Table 9. Values of nitrates, ammonium, phosphates and chlorine in the seven lagoons

 Nitrato Amonio Fosfato Cloro Nitrato Amonio Fosfato Cloro Nitrato Amonio Fosfato Cloro Límites 0.04 0.02 0.02 0.0075 0.04 0.02 0.02 0.0075 0.04 0.02 0.02 0.0075

El Carmen lagoon Average - 0.41 0.22 - 9.35 0.17 0.78 - 5.50 0.24 0.30 0.09 Median - 0.36 0.16 - 8.80 0.12 0.60 - 4.40 0.24 0.32 0.10 Machona lagonn Average 0.55 0.23 0.25 0.03 7.70 0.15 0.37 0.01 8.35 0.27 0.29 0.05 Median - 0.24 0.24 - 8.80 0.12 0.40 - 9.90 0.24 0.32 0.05 Redonda lagoon Average - 0.29 0.32 0.04 7.15 0.32 0.35 0.03 7.15 0.22 0.16 0.11 Median - 0.24 0.32 - 8.80 0.36 0.32 - 6.60 0.24 0.16 0.10 Arrastradero lagoon Average 0.55 0.27 0.29 0.01 7.15 0.29 0.80 0.01 2.20 0.24 0.86 0.08 Median - 0.24 0.24 - 6.60 0.24 0.48 - 2.20 0.24 0.84 0.10 Cocal Lagoon Average 2.20 0.22 0.29 0.05 8.07 0.30 0.40 0.02 7.33 0.27 0.19 0.10 Median 2.20 0.24 0.24 0.05 8.80 0.24 0.36 - 8.80 0.24 0.16 0.10 El Paso del Ostión Lagoon Average - 0.28 0.29 0.07 8.07 0.18 1.17 - 6.60 0.28 0.40 0.12 Median - 0.24 0.32 0.05 8.80 0.18 0.68 - 6.60 0.30 0.40 0.10 Las Palmas lagoon Average - 0.46 0.17 0.05 10.27 0.34 0.48 - 9.90 0.28 0.32 0.08 Median - 0.42 0.20 - 8.80 0.36 0.56 - 11.00 0.30 0.32 0.10

14 to take out a great amount of pollutants toward Gulf of Mexico.

mg/L

5 between 4.4 and 13.2 mg/L.

10 of Arrastradero Lagoon.

15

17 studied.

1 As for coliforms, the maximum limit of 200 NMP/100 ml set in The Ecological Criteria of 2 Water Quality (CE-CCA-001/89, 12.13.89) for Protection of Aquatic Life of fresh water was 3 surpassed in most of stations of three rivers studied in dry season.

The maximum value reached was 2400 NMP/100 ml. In rainy and norte seasons concentration of total and fecal coliforms decreased dramatically, in fact, in The Naranjeño river permissible levels were reached in these two seasons, while in The Santa Ana river this was only obtained in norte season. The San Felipe river was still classed as polluted, during the norte season. Coliforms reduction observed in rain and norte seasons was due to increases of water volume, these organisms are then dispersed and head out to sea.

The coliforms presence in the basin is of supreme importance for environmental and human health, since many aquatic organisms for human consumption, such as fish and crustaceans, are contaminated causing, in turn, gastrointestinal illnesses to consumers. The high concentrations of these organisms in the rivers are indicative of a continuous flow of black waters toward these water bodies, coming from towns and homes located on the shore. To solve this problem it is necessary to fulfill the normative on the handling of residual waters.

The Ca determined in all sites was below 18 meq/L-1 16 and it allows placing water of three rivers as soft water. The concentrations of Mg had big fluctuations between rivers and sampling seasons, being smaller those of The Naranjeño river and those of the rainy season. The behavior for Na levels was similar, the smallest corresponded to The Naranjeño river, but the season of lowest concentration was the dry season.

In the season of rains there were very high concentrations in the rivers Santa Ana and San Felipe (Table 8). The above-mentioned could be due to that there are carried out agricultural activities with more intensity in the margins of these rivers, since leaching of inorganic fertilizers contributes to salinization of natural water bodies (Wong and Rowell, 1994).

26 Table 8. Dissolved salts values: potassium, calcium, magnesium and sodium in the three 27 rivers studied.

#### 28 **3.3 Lagoons**

29 The Ecological Criteria of Water Quality (DOF, December 13 1989) set 0.04 mg/L of nitrates 30 as the maximum permissible for protection of marine aquatic life, in this sense, all the

25

15

14 Water Quality, Soil and Managing Irrigation of Crops

1 As for coliforms, the maximum limit of 200 NMP/100 ml set in The Ecological Criteria of 2 Water Quality (CE-CCA-001/89, 12.13.89) for Protection of Aquatic Life of fresh water was

The maximum value reached was 2400 NMP/100 ml. In rainy and norte seasons concentration of total and fecal coliforms decreased dramatically, in fact, in The Naranjeño river permissible levels were reached in these two seasons, while in The Santa Ana river this was only obtained in norte season. The San Felipe river was still classed as polluted, during the norte season. Coliforms reduction observed in rain and norte seasons was due to

The coliforms presence in the basin is of supreme importance for environmental and human health, since many aquatic organisms for human consumption, such as fish and crustaceans, are contaminated causing, in turn, gastrointestinal illnesses to consumers. The high concentrations of these organisms in the rivers are indicative of a continuous flow of black waters toward these water bodies, coming from towns and homes located on the shore. To solve this problem it is necessary to fulfill the normative on the handling of residual waters. The Ca determined in all sites was below 18 meq/L-1 16 and it allows placing water of three rivers as soft water. The concentrations of Mg had big fluctuations between rivers and sampling seasons, being smaller those of The Naranjeño river and those of the rainy season. The behavior for Na levels was similar, the smallest corresponded to The Naranjeño river,

In the season of rains there were very high concentrations in the rivers Santa Ana and San Felipe (Table 8). The above-mentioned could be due to that there are carried out agricultural activities with more intensity in the margins of these rivers, since leaching of inorganic fertilizers contributes to salinization of natural water bodies (Wong and Rowell, 1994).

Season Dry Rain Norte

Limits 18 18 18

26 Table 8. Dissolved salts values: potassium, calcium, magnesium and sodium in the three

29 The Ecological Criteria of Water Quality (DOF, December 13 1989) set 0.04 mg/L of nitrates 30 as the maximum permissible for protection of marine aquatic life, in this sense, all the

Naranjeño river Average 0.08 0.98 2.85 1.65 0.88 4.53 11.17 38.73 0.42 1.95 3.36 6.59 Median 0.08 0.43 0.70 1.51 0.13 3.22 1.92 4.30 0.15 1.82 1.09 1.13 Santa Ana river Average 0.44 2.64 5.69 17.05 2.94 7.94 29.41 141.8 3.11 6.41 21.76 81.25 Median 0.09 2.25 1.93 1.46 1.31 5.22 11.48 53.95 0.92 2.85 6.58 20.07 San Felipe river Average 0.21 2.71 2.03 4.95 1.02 4.14 12.48 47.88 0.45 1.19 3.04 9.61 Median 0.21 2.24 2.07 4.96 0.44 2.83 5.02 18.25 0.37 1.14 1.97 5.72

K Ca Mg Na K Ca Mg Na K Ca Mg Na

9 increases of water volume, these organisms are then dispersed and head out to sea.

3 surpassed in most of stations of three rivers studied in dry season.

20 but the season of lowest concentration was the dry season.

Meq L-1

25

27 rivers studied.

28 **3.3 Lagoons**

1 lagoons surpassed this value during the rainy and norte seasons. In the dry season all 2 lagoons, except for sampling site 3 of El Cocal lagoon, were below the reference value.

3 In most of the sampling sites nitrates were found in non-detectable quantities, however, 4 these increased until surpassing reference value in rain season (Table 9), with concentrations 5 between 4.4 and 13.2 mg/L.

This trend continued during the norte season, being detected up to 15.4 mg/L in sampling site 1 of Las Palmas lagoon, although on average concentrations were greater in the rainy season, with 8.2 mg/L than in that of the norte (6.6 mg/L). Although there were extreme values, there were also found sites with very low nitrate concentrations such as sites 2 and 3 of Arrastradero Lagoon.

Increase of nitrates quantities during rainy and norte seasons seems to be result of the influence of a greater water volume, rich in nutritious material coming from human activities that the rivers catch; since in dry season entrance of seawater with its tides allows to take out a great amount of pollutants toward Gulf of Mexico.

16 Table 9. Values of nitrates, ammonium, phosphates and chlorine in the seven lagoons 17 studied.

 Turbidity, dissolved oxygen, biochemistry oxygen demand of and total solids

Values of total suspended solids were very above the 125 mg/L (daily average) set as the permissible maximum limit in the same standard (NOM-001-ECOL-1996) for estuaries in the three sampling seasons, especially in those of rain and norte. Increment of total suspended solids in the water coincides with the values obtained in the rivers studied that drag a great quantity of materials from the soil that are carried to coastal lagoons in high precipitation

Almost all pH values reported are within the allowed range in the standard (NOM-001- ECOL-1996) for residual water discharges in waters and national goods that goes from 5 to 10, and of Canadian Guide of Environmental Water Quality (December, 2003) that allows values between 6.5 and 8.5. The average values of obtained pH were 7.4, 7.5 and 7.3 for the

The same as for rivers, concentrations of total and fecal coliforms were extraordinarily high in dry season, decreasing up to concentrations bellow the limit in the rainy and norte seasons; the mean values were 931, 195 and 10 NMP/100 ml for dry, rain and norte,

values in the seven lagoons studied

season to be finally deposited in Gulf of Mexico.

dry, rainy and norte seasons, respectively (Table 11).

In water, ammonium can be shown in two chemical species whose proportion depends on hydrogen potential (pH) and temperature. One of them is ionized ammonium or NH4+ and the other is ammonia or not ionized ammonium (NH3) which is much more toxic and, by its property of being liposoluble, it can cross biological protection barriers and to cause toxicological damage such as generating methemoglobinemia in fish, which impedes blood oxygenation, as well as degrading cellular membranes, and destroying gills with which fish breathe (Mangas, 2000).

Ammonium detected in the systems studied kept an almost constant level in three sampling seasons (Table 9). Although average values slightly varied, median in each one of sampling seasons was of 0.24 mg/L. All detected values thoroughly surpassed maximum value of ammonia nitrogen set in The Ecological Criteria of Water Quality (DOF, December 13 1989) for Protection of Aquatic Life (seawater) of 0.01 mg/L and tolerance limit for fish of 0.02 mg/L of NH3 (EIFAC, 1973).

Practically in all sampling sites and in the three seasons of year phosphates were also above the limits allowed by the Ecological Criteria of Water Quality (CE-CCA-001/89 12.13.89) for Protection Aquatic Life, which in the case of coastal systems allows concentrations of up to 0.02 mg/L.

In all sampling sites of the seven lagoons and in the three considered seasons, phosphates values greatly surpassed the limits, most of the values detected being around 0.24 mg/L in dry season, 0.4 mg/L in that of rainy season and 0.32 in that of norte season.

Results obtained in this study coincide with that found by INE (2000) in lagoon system Carmen-Machona, where it was reported that orthophosphates (PO4) and nitrates (NO3) values exceeded maximum limits for protection of seawater life in The Ecological Criteria.

Residual chlorine levels are relatively low in dry and rain seasons, excepting stations 3 of El Cocal lagoon and 2 of Paso de Ostión lagoon that, in the dry season surpassed limits set in the Ecological Criteria of Water Quality (CE-CCA-001/89 12.13.89) for Protection of Seawater Life, it is of up to 0.0075 mg/L. In the norte season only stations 1 of Machona lagoon and 4 of Redonda lagoon had residual chlorine of non-detectable concentrations, between 0.1 and 0.36 mg/L.

Except for some few cases, mainly in dry season, turbidity generally stayed below the 40 NTU that is maximum acceptable for development of aquatic communities, according to water contamination control (UNESCO, 1995) (Table 10). This was expected due continuous exchange of fresh water and salt water with the sea 'allows diluting' organic matter coming from rivers.

In general, in the lagoons studied there were found to be appropriate levels of O2 in dry and rain seasons, according to The Ecological Criteria of Water Quality (DOF, December 13 1989) for Protection Seawater Life (marine) that set OD levels superior to 5.0 mg/L.

Contrarily, for the norte season it was found a considerable number of sites with concentrations smaller than those allowed for protection of seawater fauna, specifically in Redonda, Cocal and Las Palmas lagoons. The above-mentioned could be due to a considerable haulage of organic matter toward the lagoon through rivers that promoted proliferation of heterotroph organisms, which consume large quantities of oxygen. That contrasts with DBO data, since in all lagoons, in the three sampling seasons the detected levels were very below the 75 mg/L that the Mexican Official Standard (NOM-001-ECOL-1996) sets as permissible maximum limit as daily average.

In water, ammonium can be shown in two chemical species whose proportion depends on hydrogen potential (pH) and temperature. One of them is ionized ammonium or NH4+ and the other is ammonia or not ionized ammonium (NH3) which is much more toxic and, by its property of being liposoluble, it can cross biological protection barriers and to cause toxicological damage such as generating methemoglobinemia in fish, which impedes blood oxygenation, as well as degrading cellular membranes, and destroying gills with which fish

Ammonium detected in the systems studied kept an almost constant level in three sampling seasons (Table 9). Although average values slightly varied, median in each one of sampling seasons was of 0.24 mg/L. All detected values thoroughly surpassed maximum value of ammonia nitrogen set in The Ecological Criteria of Water Quality (DOF, December 13 1989) for Protection of Aquatic Life (seawater) of 0.01 mg/L and tolerance limit for fish of 0.02

Practically in all sampling sites and in the three seasons of year phosphates were also above the limits allowed by the Ecological Criteria of Water Quality (CE-CCA-001/89 12.13.89) for Protection Aquatic Life, which in the case of coastal systems allows concentrations of up to

In all sampling sites of the seven lagoons and in the three considered seasons, phosphates values greatly surpassed the limits, most of the values detected being around 0.24 mg/L in

Results obtained in this study coincide with that found by INE (2000) in lagoon system Carmen-Machona, where it was reported that orthophosphates (PO4) and nitrates (NO3) values exceeded maximum limits for protection of seawater life in The Ecological Criteria. Residual chlorine levels are relatively low in dry and rain seasons, excepting stations 3 of El Cocal lagoon and 2 of Paso de Ostión lagoon that, in the dry season surpassed limits set in the Ecological Criteria of Water Quality (CE-CCA-001/89 12.13.89) for Protection of Seawater Life, it is of up to 0.0075 mg/L. In the norte season only stations 1 of Machona lagoon and 4 of Redonda lagoon had residual chlorine of non-detectable concentrations,

Except for some few cases, mainly in dry season, turbidity generally stayed below the 40 NTU that is maximum acceptable for development of aquatic communities, according to water contamination control (UNESCO, 1995) (Table 10). This was expected due continuous exchange of fresh water and salt water with the sea 'allows diluting' organic matter coming

In general, in the lagoons studied there were found to be appropriate levels of O2 in dry and rain seasons, according to The Ecological Criteria of Water Quality (DOF, December 13 1989)

Contrarily, for the norte season it was found a considerable number of sites with concentrations smaller than those allowed for protection of seawater fauna, specifically in Redonda, Cocal and Las Palmas lagoons. The above-mentioned could be due to a considerable haulage of organic matter toward the lagoon through rivers that promoted proliferation of heterotroph organisms, which consume large quantities of oxygen. That contrasts with DBO data, since in all lagoons, in the three sampling seasons the detected levels were very below the 75 mg/L that the Mexican Official Standard (NOM-001-ECOL-

for Protection Seawater Life (marine) that set OD levels superior to 5.0 mg/L.

1996) sets as permissible maximum limit as daily average.

dry season, 0.4 mg/L in that of rainy season and 0.32 in that of norte season.

breathe (Mangas, 2000).

mg/L of NH3 (EIFAC, 1973).

between 0.1 and 0.36 mg/L.

0.02 mg/L.

from rivers.

Table 10. Turbidity, dissolved oxygen, biochemistry oxygen demand of and total solids values in the seven lagoons studied

Values of total suspended solids were very above the 125 mg/L (daily average) set as the permissible maximum limit in the same standard (NOM-001-ECOL-1996) for estuaries in the three sampling seasons, especially in those of rain and norte. Increment of total suspended solids in the water coincides with the values obtained in the rivers studied that drag a great quantity of materials from the soil that are carried to coastal lagoons in high precipitation season to be finally deposited in Gulf of Mexico.

Almost all pH values reported are within the allowed range in the standard (NOM-001- ECOL-1996) for residual water discharges in waters and national goods that goes from 5 to 10, and of Canadian Guide of Environmental Water Quality (December, 2003) that allows values between 6.5 and 8.5. The average values of obtained pH were 7.4, 7.5 and 7.3 for the dry, rainy and norte seasons, respectively (Table 11).

The same as for rivers, concentrations of total and fecal coliforms were extraordinarily high in dry season, decreasing up to concentrations bellow the limit in the rainy and norte seasons; the mean values were 931, 195 and 10 NMP/100 ml for dry, rain and norte,

Water Quality at the Cárdenas-Comalcalco Basin, México 19

1 being of high commercial value, it is seen that in the region, it reaches only marginal prices

Oysters generally are edible in fresh or smoked, in which coliforms imply serious risks to human health. On the other hand, the study area has potential for tourism development, due to its natural beauty; however, coliforms contamination excludes it as non-appropriate area for recreational use, according to the Ecological Criteria of Water Quality (DOF,

8 In the current normative there were not maximum values of concentration for K, Ca, Mg 9 and Na; however, the detected values are normal for lagoons and coastal estuaries. They

Season Dry Rain Norte

Table 12. Potassium, calcium, magnesium and sodium values in the seven studied lagoons Finally, it is important to mention that analyses of heavy metals of all wells, rivers and lagoons, were in non-detectable quantities, therefore they are considered clean of these dangerous compounds for wild life and human health. According to The Ecological Criteria of Water Quality (DOF, December 13 1989) maximum permissible values in coastal lagoons for

K Ca Mg Na K Ca Mg Na K Ca Mg Na

El Carmen lagoon Average 6.04 12.50 71.24 261.74 10.00 18.39 105.18 530.98 9.87 18.87 93.75 275.54 Median 5.49 12.38 67.00 251.10 10.00 18.25 107.35 528.25 10.09 19.16 92.52 250.00 Machona lagoon Average 6.41 10.62 58.20 295.16 9.94 18.35 107.93 507.08 9.39 17.41 103.52 229.35 Median 6.08 12.01 62.50 283.50 9.90 18.60 109.35 495.65 10.17 19.81 113.90 258.70 Redonda lagoon Average 0.69 1.99 6.78 28.08 8.98 17.26 101.98 440.21 7.51 12.12 68.77 176.41 Median 0.65 1.96 6.15 25.05 9.05 17.20 102.80 450.00 7.56 12.07 69.08 167.39 Arrastradero lagoon Average 0.23 1.35 2.23 7.80 1.53 5.46 21.10 71.64 5.57 11.22 108.24 242.55 Median 0.25 1.49 2.20 8.18 1.55 4.89 20.15 68.50 5.55 11.17 57.15 238.48 Cocal lagoon Average 0.04 4.17 3.37 3.57 3.88 0.16 5.63 0.14 44.00 0.09 0.36 0.09 Median 0.04 4.07 3.50 3.02 3.50 0.15 5.00 - 30.80 0.12 0.32 - El Paso del Ostión lagoon Average 0.33 1.57 3.30 12.62 3.75 11.33 51.93 188.78 5.26 9.85 60.03 204.64 Median 0.34 1.54 3.25 12.45 3.70 11.00 50.55 187.80 5.33 10.30 60.03 216.74 Las Palmas lagoon Average 2.60 5.42 25.48 116.52 7.40 15.45 85.67 383.00 9.38 18.32 101.29 276.09 Median 2.52 5.09 28.35 107.60 9.20 17.55 99.95 473.95 9.58 18.69 101.97 267.39

2 due to accumulation of coliforms consequence of their screening food habits.

7 December 13 1989) that set a maximum of 200 NMP/100 ml.

Meq L-1

10 were considered appropriate for aquatic life (Table 12).

11

1 respectively. Values of dry season were greater than minimum of 200 NMP/100 ml that are 2 set by The Ecological Criteria of Water Quality (CE-CCA-001/89 12.13.89) for Protection of 3 Seawater Life (marine water).

5 Table 11. pH, electric conductivity, temperature, and total and fecal coliforms values in the 6 seven lagoons studied.

The most polluted lagoons, whose higher values surpassed the standard in dry and rainy seasons were El Paso del Ostión, Las Palmas and Cocal, because they are water bodies which are relatively closed and that only have communication with other lagoons in growing season, between October and November, which means that in dry season they do not receive replacement of sea water, and this is the reason why nutrients and microorganisms remain concentrated.

13 Presence of high concentrations of total and fecal coliforms in lagoons studied represents a 14 serious problem for regions economic activities, in principle because fishing is an important 15 economic activity in surrounding communities.

16 This has serious effects on fish and captured crustacean quality and it influences negatively 17 in sale price. The most dramatic case is that of oyster production (*Crassostrea viginica*) that,

4

11

18 Water Quality, Soil and Managing Irrigation of Crops

 pH CE T° C-T C-F pH CE T° C-T C-F pH CE T° C-T C-F 6.5-8 <200 <200 6.5-8 <200 <200 6.5-8 <200 <200 Laguna El Carmen Average 7.35 31.59 27.78 1086 712.9 7.66 43.36 28.26 126.13 119.75 10.33 6.56 27.7 19999 7369.9 Median 7.39 28.63 27.65 716 590.0 7.66 45.21 28.35 129.00 120.50 9.81 6.63 27.5 19999 7321.5 Laguna Machona Average 7.61 41.62 28.06 827 450.3 7.60 46.21 28.83 157.38 149.13 9.24 6.75 27.8 19364 7284.9 Median 7.57 32.74 28.75 345 290.5 7.58 48.82 28.85 144.00 137.00 8.49 6.97 27.9 19999 7302.5 Laguna Redonda Average 7.64 3.49 28.38 2237 574.4 7.26 44.36 29.59 115.00 108.13 15.83 4.77 28.2 19442 7236.6 Median 7.66 3.23 28.40 2400 500.0 7.22 44.50 29.45 100.50 97.00 11.85 4.76 28.3 19606 7217.5 Laguna Arrastradero Average 7.97 1.23 28.85 1992 792.5 7.73 9.27 30.55 125.88 119.88 11.95 6.56 28.7 16714 7614.5 Median 7.81 1.31 28.80 2400 675.0 7.68 8.52 30.20 93.00 91.00 11.10 6.63 29.1 16826 7713.0 Laguna Cocal Average 7.74 2.83 28.68 2400 1098.3 7.24 27.19 29.87 295.17 283.00 10.44 4.09 28.5 15213 7089.0 Median 7.72 2.59 28.50 2400 1075.0 7.24 27.04 29.70 295.50 280.00 11.00 3.94 28.5 15636 7042.5 Laguna El Paso del Ostión Average 6.72 1.79 28.83 2325 1220.8 7.37 23.15 30.72 494.33 456.67 11.47 5.45 28.1 16242 7305.3 Median 7.50 1.84 28.75 2400 1040.0 7.31 22.69 30.65 602.50 530.00 10.85 5.01 27.9 17116 7381.5 Laguna Las Palmas Average 7.28 14.82 28.47 2250 2070.0 7.40 33.99 28.17 243.67 230.17 10.45 4.11 27.6 19999 6989.3 Median 7.23 14.82 28.55 2400 2400.0 7.39 35.68 28.20 215.00 211.00 9.40 4.02 27.9 19999 6960.5 Unidades de medida. CE: dS m-1; T°: °C; C-T y C-F: NMP/100 mL

1 respectively. Values of dry season were greater than minimum of 200 NMP/100 ml that are 2 set by The Ecological Criteria of Water Quality (CE-CCA-001/89 12.13.89) for Protection of

Época Secas Lluvias Nortes

5 Table 11. pH, electric conductivity, temperature, and total and fecal coliforms values in the

The most polluted lagoons, whose higher values surpassed the standard in dry and rainy seasons were El Paso del Ostión, Las Palmas and Cocal, because they are water bodies which are relatively closed and that only have communication with other lagoons in growing season, between October and November, which means that in dry season they do not receive replacement of sea water, and this is the reason why nutrients and

13 Presence of high concentrations of total and fecal coliforms in lagoons studied represents a 14 serious problem for regions economic activities, in principle because fishing is an important

16 This has serious effects on fish and captured crustacean quality and it influences negatively 17 in sale price. The most dramatic case is that of oyster production (*Crassostrea viginica*) that,

3 Seawater Life (marine water).

6 seven lagoons studied.

12 microorganisms remain concentrated.

15 economic activity in surrounding communities.

4

1 being of high commercial value, it is seen that in the region, it reaches only marginal prices 2 due to accumulation of coliforms consequence of their screening food habits.

Oysters generally are edible in fresh or smoked, in which coliforms imply serious risks to human health. On the other hand, the study area has potential for tourism development, due to its natural beauty; however, coliforms contamination excludes it as non-appropriate area for recreational use, according to the Ecological Criteria of Water Quality (DOF, December 13 1989) that set a maximum of 200 NMP/100 ml.

8 In the current normative there were not maximum values of concentration for K, Ca, Mg 9 and Na; however, the detected values are normal for lagoons and coastal estuaries. They 10 were considered appropriate for aquatic life (Table 12).

12 Table 12. Potassium, calcium, magnesium and sodium values in the seven studied lagoons

Finally, it is important to mention that analyses of heavy metals of all wells, rivers and lagoons, were in non-detectable quantities, therefore they are considered clean of these dangerous compounds for wild life and human health. According to The Ecological Criteria of Water Quality (DOF, December 13 1989) maximum permissible values in coastal lagoons for

Water Quality at the Cárdenas-Comalcalco Basin, México 21

Arce, O. (2006). *Indicadores biológicos del agua*. Universidad Mayor de San Simón, Facultad de

Breitburg, D.L.; T. Loher, A. Pacey & A. Gerstein. (1997). Varying Effects of Low Dissolved Oxygen on Trophic Interactions in an Estuarine Food Web. *Ecological Monographs*,

Camargo, J.A. & A. Alonso (Lead Authors); Raphael D. Sagarin (Topic Editor). (2007) "Inorganic nitrogen pollution in aquatic ecosystems: causes and consequences." In: *Encyclopedia of Earth*. Eds. Cutler J. Cleveland (Washington, D.C. Environmental Information Coalition, National Council for Science and the Environment). [First published in the Encyclopedia of Earth April 2, 2007; Last revised April 11, 2007;

CE-CCA-001/89. (8) 12-13-89 ACUERDO por el que se establecen los *Criterios Ecológicos de*

Dourojeanni, A. y A. Jouraviev. 2001. Crisis de gobernabilidad en la gestión del agua: Desafíos que enfrenta la implementación de las recomendaciones contenidas en el capítulo 18 del Programa 21. CEPAL. Serie Recursos Naturales e Infraestructura.

EIFAC, 1973. Water quality criteria for European freshwater fish. Report on ammonia and

INE. Instituto Nacional de Ecología (2000). *La calidad del agua en los ecosistemas costeros de*

López T.D., M.O. Pérez, G. Mazari, H. Marisa & M Maas. (No date). *Reserva de la biósfera Chamela-Cuixmala: un estudio de calidad del agua, bajo un enfoque de manejo integrado de*

Mangas, R.E. (2000). *Evaluación de los Efectos de la Remoción del Lirio Acuático (Eichhornia crassipes) en la Biota y la Calidad del Agua en el Embalse Manuel Ávila Camacho, en el*

National Research Council. (1995). *Nitrate and Nitrite in Drinking Water*. Subcommittee on Nitrate and Nitrite in Drinking Water, Committee on Toxicology, National

Nebel, B. & R. Wrigth. (1999). *Ciencias ambientales: Ecología y Desarrollo Sostenible*. Sexta

NOM-001/SEMARNAT-1996. *Norma Oficial Mexicana para Límites máximos permisibles de contaminantes en las descargas de aguas residuales en aguas y bienes nacionales*. DOF. NOM-127-SSA1-1994. Norma *Oficial Mexicana de Salud ambiental, agua para uso y consumo humano, limites permisibles de calidad y tratamientos a que debe someterse el agua*. DOF. Pontius, N.L. (2002). *Coliform Bacteria, Regulatory Briefing*. National Rural Water Association.

Ramirez, J., F.L. Gutiérrez, & A. Vargas. (2005). Phytoplankton community response to artificial eutrophication experiments conducted in the La Fe reservoir, El Retiro,

Reynolds, J.D.& H.P. Guillaume. 1998. Effects of phosphate on the reproductive symbiosis between bitterling and freshwater mussels: implications for conservation. *The*

*Calidad del Aguas*. Instituto Nacional de Ecología. México, D.F.

*México*. México, D.F. (disponible en http://www.ine.gob.mx)

*Edo. De Puebla*. Tesis de Maestría. Instituto de Ciencias. BUAP.

inland fisheries. *Water Ressources* No. 7: 1010–1022.

**5. References**

Vol. 67, No. 4: 489–507

Retrieved April 29, 2008].

Academy Press Washington D.C.

Edición. Prentice-Hall. México. Pp. 720.

Antioquia, Colombia. *Caldasia*, 27(1):103-115.

*Journal of Applied Ecology*. Vol. No. 35(4): 575-581

Chile. Pp. 84.

*cuencas*.

Duncan, UK.

Ciencias y Tecnología. Cochabamba, Bolivia.

Pb, Ni and Zn is 0.006, 0.008, 0.09 mg/L. In the actual norm there were no references to safe Va concentrations in water, however, the standards of European Union for Marine Water establish a maximum value of 100 µgV/L (http://www.ukmarinesac.org.uk/activities/water-quality/wq4\_1\_2.htm).

#### **4. Conclusions and recommendations**

#### **4.1 Conclusions**

The greatest source of contamination in The Cárdenas-Comalcalco basin are high concentrations of total and fecal coliforms that exceed to a major degree the maximum permissible for the protection of human health and wild fauna. Up to this moment this is a problem of public and environmental health that seems not to be studied by the involved sectors.

Sources of water chemical contamination in the basin are nitrates and the phosphates. The presence of nitrates in wells for human consumption can represent a continuous risk for population, since impact can occur in long term and to go unseen by the population.

Nitrates, ammonium and phosphate concentrations in natural water bodies were very high. Although scope of this study did not contemplate to measure effects on the biological community in the locations studied, there is solid evidence that levels similar to the ones found in the area have an adverse effect on fauna and water productivity. The negative outcome to environmental and to economic activities is unknown, but, according to similar studies, it could be considerable.

Concentrations of organic and inorganic pollutants tend to increase in the rainy and norte seasons due to run off of urban and agricultural organic residuals due the rain flows. Concentrations of these pollutants were smaller in lagoons that are connected to sea due to water exchange between both systems.

#### **4.2 Recomendations**

Implementation of a program to improve underground and superficial water quality of basin is necessary. The establishment of a legal base that allows the application of effective standards of environmental quality is required. It is necessary for greater control on agrochemicals used in agricultural activities and the design and construction of septic graves and drainage systems and appropriate treatment of residual waters in rural areas. In the same way, it is necessary to regulate existent industrial activities and that environmental quality standards are met in new industries.

It is recommended the implementation of well handling training programs at homes, and also educational programs focused to prevention of gastrointestinal illnesses caused by water polluted with coliforms and nitrogenated compounds.

It is necessary the realization of studies that allow to measure with more detail conditions of this basin, in which are carried out finer measurements of heavy metals to determine very small concentrations.

In the same way, it is necessary to carry out works that contemplate a greater number of sampling stations and a greater number of measurements throughout the year. Also, it is important to contemplate smaller water bodies that remain closed most part of the year, since results of this work indicate that in fact it is in these type of water bodies, where there are concentrated the greatest quantities of pollutants. The above-mentioned would allow obtaining enough information to propose reparation programs.

#### **5. References**

Water Quality, Soil and Managing Irrigation of Crops

Pb, Ni and Zn is 0.006, 0.008, 0.09 mg/L. In the actual norm there were no references to safe Va concentrations in water, however, the standards of European Union for Marine Water establish a maximum value of 100 µgV/L (http://www.ukmarinesac.org.uk/activities/water-

The greatest source of contamination in The Cárdenas-Comalcalco basin are high concentrations of total and fecal coliforms that exceed to a major degree the maximum permissible for the protection of human health and wild fauna. Up to this moment this is a problem of public and environmental health that seems not to be studied by the involved

Sources of water chemical contamination in the basin are nitrates and the phosphates. The presence of nitrates in wells for human consumption can represent a continuous risk for

Nitrates, ammonium and phosphate concentrations in natural water bodies were very high. Although scope of this study did not contemplate to measure effects on the biological community in the locations studied, there is solid evidence that levels similar to the ones found in the area have an adverse effect on fauna and water productivity. The negative outcome to environmental and to economic activities is unknown, but, according to similar

Concentrations of organic and inorganic pollutants tend to increase in the rainy and norte seasons due to run off of urban and agricultural organic residuals due the rain flows. Concentrations of these pollutants were smaller in lagoons that are connected to sea due to

Implementation of a program to improve underground and superficial water quality of basin is necessary. The establishment of a legal base that allows the application of effective standards of environmental quality is required. It is necessary for greater control on agrochemicals used in agricultural activities and the design and construction of septic graves and drainage systems and appropriate treatment of residual waters in rural areas. In the same way, it is necessary to regulate existent industrial activities and that environmental

It is recommended the implementation of well handling training programs at homes, and also educational programs focused to prevention of gastrointestinal illnesses caused by

It is necessary the realization of studies that allow to measure with more detail conditions of this basin, in which are carried out finer measurements of heavy metals to determine

In the same way, it is necessary to carry out works that contemplate a greater number of sampling stations and a greater number of measurements throughout the year. Also, it is important to contemplate smaller water bodies that remain closed most part of the year, since results of this work indicate that in fact it is in these type of water bodies, where there are concentrated the greatest quantities of pollutants. The above-mentioned would allow

population, since impact can occur in long term and to go unseen by the population.

quality/wq4\_1\_2.htm).

studies, it could be considerable.

**4.2 Recomendations**

very small concentrations.

water exchange between both systems.

quality standards are met in new industries.

water polluted with coliforms and nitrogenated compounds.

obtaining enough information to propose reparation programs.

**4.1 Conclusions**

sectors.

**4. Conclusions and recommendations**

**2**

*1South Africa 2,3India*

**Effluent Quality Parameters**

*North-West University, Mafikeng Campus, Mmabatho,*

*3Department of Botany, Aligarh Muslim University,*

Hamid Iqbal Tak1, Yahya Bakhtiyar2, Faheem Ahmad1 and Arif Inam3 *1Department of Biological Sciences, Faculty of Agriculture, Science and Technology,*

"When the well is dry, we know the worth of water." Benjamin Franklin, (1706-1790), Poor Richard's Almanac, 1746 Fast depletion of groundwater reserves, coupled with severe water pollution, has put governments all over the world in a difficult position to provide sufficient fresh water for our daily use. Ismail Serageldin vice president of World Bank in 1995 predicted that "if the wars of this century were fought over oil, the wars of the next century will be fought for water". Thus it signifies the role water is going to play in the current century we live in. At the same time, the need for sustained food production to feed the hungry mouths of the ever increasing population is apparent. In many arid and semi-arid countries since water is becoming increasingly scarce resource and planners are forced to consider alternate sources of water which might be used economically and effectively. The use of wastewater (WW) for crop irrigation as an alternative for effluent water disposal and for freshwater (FW) usage is common worldwide in countries in which water is scarce. Disposal of wastewater is also a problem of increasing importance throughout the world including India. Both the need to conserve fresh water and to safe and economically dispose of wastewater makes its use in agriculture a very feasible option. Furthermore, wastewater reuse may reduce fertilizer rates in addition to low cost source of irrigation water. In many parts of the world, treated municipal wastewater and raw sewage wastewater and even industrial wastewater has been successfully used for the irrigation of various crops (Asano and Tchobanoglous 1987, Adriel et al., 2007; Tak et al., 2010). It is well known that the enteric diseases, anaemia and gastrointestinal illnesses are high among sewage wastewater farmers. In addition, the consumers of vegetable crops which are eaten uncooked and grown without any treatment are also at risk. This chapter particularly envisages the review on the safe and quality

The use of sewage effluents for agricultural irrigation is an old and popular practice in agriculture (Feigin et al., 1984). Irrigation with wastewater has been used for three purposes:

ii. use of marginal water as an available water source for agriculture (Al-Jaloud et al., 1995;

i. complementary treatment method for wastewater (Bouwer & Chaney, 1974);

Tanji, 1997) – a sector demanding ~ 70% of the consumptive water use.

parameters of wastewater for sustainable use in agriculture.

**1. Introduction**

**for Safe use in Agriculture**

*2Department of Zoology, Jammu University,*

### **Effluent Quality Parameters for Safe use in Agriculture**

Hamid Iqbal Tak1, Yahya Bakhtiyar2, Faheem Ahmad1 and Arif Inam3 *1Department of Biological Sciences, Faculty of Agriculture, Science and Technology, North-West University, Mafikeng Campus, Mmabatho, 2Department of Zoology, Jammu University,*

*3Department of Botany, Aligarh Muslim University, 1South Africa 2,3India*

#### **1. Introduction**

22 Water Quality, Soil and Managing Irrigation of Crops

1 Russo, R.C. (1985) *Ammonia, Nitrite, and Nitrate Fundamentals of Aquatic Toxicology: Methods and*  2 *Applications*. Hemisphere Publishing Corporation Washington DC. 1985. p 455-471. 3 Safe Drinking Water Comm. (1980). *Drinking water and health*. Vol 3. Nat. Acad. Press,

5 Scotish Natural Heritage. (1996). *Rivers and their catchments: causes and effects of turbid water*.

7 Shoji, J., R. Masuda, Y. Yamashita, & M. Tanaka. (2005) Effect of low dissolved oxygen 8 concentrations on behavior and predation rates on red sea bream *Pagrus major* 9 larvae by the jellyfish *Aurelia aurita* and by juvenile Spanish mackerel

UNESCO, 1995. *Agua para Todos, agua para la vida*. Informe de las Naciones Unidas sobre el Desarrollo de los Recursos Hídricos en el Mundo (versión española del UN WWDR). Ediciones Mundi-Prensa (www.mundiprensa.com). Gestión de la Calidad del Agua y Control de la Contaminación en América Latina y el Caribe.

16 Wong M.T.F. & D.L. Rowell. (1994). Leaching of nutrients from undisturbed lysimeters of a 17 cleared Ultisol, an Oxisol collected under rubber plantation and an Inceptisol.

10 *Scomberomorus niphonius*. *Marine Biology*, Vol. 147, No. 4, pp. 863-868.

4 Washington, 415 pp.

6 Information & Advisory Note 22

15 www.unesco.org/publishing

18 *Interciencia* 19(6): 352-355.

"When the well is dry, we know the worth of water." Benjamin Franklin, (1706-1790), Poor Richard's Almanac, 1746

Fast depletion of groundwater reserves, coupled with severe water pollution, has put governments all over the world in a difficult position to provide sufficient fresh water for our daily use. Ismail Serageldin vice president of World Bank in 1995 predicted that "if the wars of this century were fought over oil, the wars of the next century will be fought for water". Thus it signifies the role water is going to play in the current century we live in. At the same time, the need for sustained food production to feed the hungry mouths of the ever increasing population is apparent. In many arid and semi-arid countries since water is becoming increasingly scarce resource and planners are forced to consider alternate sources of water which might be used economically and effectively. The use of wastewater (WW) for crop irrigation as an alternative for effluent water disposal and for freshwater (FW) usage is common worldwide in countries in which water is scarce. Disposal of wastewater is also a problem of increasing importance throughout the world including India. Both the need to conserve fresh water and to safe and economically dispose of wastewater makes its use in agriculture a very feasible option. Furthermore, wastewater reuse may reduce fertilizer rates in addition to low cost source of irrigation water. In many parts of the world, treated municipal wastewater and raw sewage wastewater and even industrial wastewater has been successfully used for the irrigation of various crops (Asano and Tchobanoglous 1987, Adriel et al., 2007; Tak et al., 2010). It is well known that the enteric diseases, anaemia and gastrointestinal illnesses are high among sewage wastewater farmers. In addition, the consumers of vegetable crops which are eaten uncooked and grown without any treatment are also at risk. This chapter particularly envisages the review on the safe and quality parameters of wastewater for sustainable use in agriculture.

The use of sewage effluents for agricultural irrigation is an old and popular practice in agriculture (Feigin et al., 1984). Irrigation with wastewater has been used for three purposes: i. complementary treatment method for wastewater (Bouwer & Chaney, 1974);

ii. use of marginal water as an available water source for agriculture (Al-Jaloud et al., 1995; Tanji, 1997) – a sector demanding ~ 70% of the consumptive water use.

Effluent Quality Parameters for Safe use in Agriculture 25

through the irrigation water. Water with an ECw of only 1.15 dS/m contains approximately 2,000 pounds of salt for every acre foot of water. You can use conversion factors in Table 2 to

(dS/m)\*

Table 1. General guidelines for salinity hazard of irrigation water based upon conductivity. Salt-affected soils develop from a wide range of factors including: soil type, field slope and drainage, irrigation system type and management, fertilizer and manuring practices, and other soil and water management practice. However, the most critical factor in predicting, managing, and reducing salt-affected soils is the quality of irrigation water being used. Besides affecting crop yield and soil physical conditions, irrigation water quality can affect fertility needs, irrigation system performance and longevity, and how the water can be applied. Therefore, knowledge of irrigation water quality is critical to understanding what

Electrical conductivity (EC) is the most convenient way of measuring water salinity. EC is determined as the reciprocal of the specific resistance (ohms.m) of the water sample corrected to a standard temperature, usually 25°C.The basic unit of EC in SI units is Siemens m-1 (previously mhos m-1). Formerly water salinities were expressed in micro mhos cm-1.

Frequently EC is multiplied by a factor to obtain total soluble salts (mass/volume) as an expression of salinity. There is however no unique factor that can be applied and the factor will vary with composition and concentration. Factors found for W.A. waters vary between 5.0 and 8.5 (EC in mS m-1). Generally it is more convenient to use electrical conductivity as the measure of salt content as criteria are usually published in this form. Other terms that laboratories and literature sources use to report salinity hazard are: salts, salinity, electrical conductivity (ECw), or total dissolved solids (TDS). These terms are all comparable and all quantify the amount of dissolved "salts" (or ions, charged particles) in a water sample. However, TDS is a direct measurement of dissolved ions and EC is an indirect measurement of ions by an electrode. Although people frequently confuse the term "salinity" with common table salt or sodium chloride (NaCl), EC measures salinity from all the ions dissolved in a

Ca++, Na+). Another common source of confusion is the variety of unit systems used with ECw. The preferred unit is deciSiemens per meter (dS/m), however millimhos per centimeter (mmho/cm) and micromhos per centimeter (µmho/cm) are still frequently used. Conversions

, NO-

3) and positively charged ions (e.g.,

make this calculation for other water EC levels.

None ≤0.75 Some 0.76 - 1.5 Moderate1 1.51 - 3.00 Severe2 ≤3.00

\*dS/m at 25ºC=mmhos/cm 1Leaching required at higher range.

Some useful conversions are:

1 mS m-1 = 0.01 m mho cm-1 =10 mµho cm-1

sample. This includes negatively charged ions (e.g., Cl-

to help you change between unit systems are provided in Table 2.

Limitations for use Electrical Conductivity

2Good drainage needed and sensitive plants may have difficulty at germination.

management changes are necessary for long-term productivity.

e.g. a water may have EC = 2000 µmho cm-1 = 2 mmho cm-1 = 200 mS m-1

iii. use of wastewater as nutrient source (Bouwer & Chaney, 1974; Vazquez- Montiel et al., 1996) associated with mineral fertilizer savings and high crop yields (Feigin et al., 1991; Tak et al., 2010).

Irrigated agriculture is dependent on an adequate water supply of usable quality. Water quality concerns have often been neglected and the situation is now changing in many areas. To avoid problems when using these poor quality water supplies, there must be sound planning to ensure that the quality of water available is put to the best use. The objective of this article is to help the reader in better understanding of the effect of water quality upon soil and crops and to assist in selecting suitable alternatives to cope with potential water quality related problems that might reduce production under prevailing conditions of use. Thus knowledge of irrigation water quality is critical in understanding management for its long-term usage and productivity. Conceptually, water quality refers to the characteristics of water that will influence its suitability for a specific use, i.e. how well the quality meets the needs of the user. Quality is defined by certain physical, chemical and biological characteristics. Even a personal preference such as taste is a simple evaluation of acceptability. For example, if two drinking waters of equally good quality are available, people may express a preference for one supply rather than the other; the better tasting water becomes the preferred supply. In irrigation water evaluation, however, the emphasis is placed on the chemical and physical characteristics of water and only rarely is any other factor considered important. There have been a number of different water quality guidelines related to use of wastewater in agriculture. Each has been useful but none has been entirely satisfactory because of the wide variability in field conditions. The guidelines presented in this paper have also relied on previous ones but are modified for evaluating and managing water quality-related problems of irrigated agriculture.

#### **2. Irrigation water quality criteria**

Soil scientists use various physico chemical parameters to describe irrigation water effects on crop production and soil quality. These include, Salinity hazard - total soluble salt content, Sodium hazard - relative proportion of sodium to calcium and magnesium ions, pH - acidic or basic, Alkalinity - carbonate and bicarbonate, Specific ions: chloride, sulfate, boron, and nitrate. However, another potential irrigation water quality parameter that may affect its suitability for agricultural system is microbial pathogens, which has often been neglected.

#### **2.1 Salinity hazard /electrical conductivity**

The most influential water quality guideline on crop productivity is the water salinity hazard as measured by electrical conductivity (ECw). The primary effect of high ECw water on crop productivity is the inability of the plant to compete with ions in the soil solution for water a condition known as Osmotic drought (physiological drought). Higher the EC, lesser is the water available to plants, even though the soil may appear to be wet. Because plants can only transpire "pure" water, usable plant water in the soil solution decreases dramatically as EC increases. An actual yield reduction from irrigation with high EC water varies substantially. Factors influencing yield reductions include soil type, drainage, salt type, irrigation system and management. The amount of water transpired through a crop is directly related to yield; therefore, irrigation water with high ECw reduces yield potential (Table 1). Beyond effects on the immediate crop is the long term impact of salt loading through the irrigation water. Water with an ECw of only 1.15 dS/m contains approximately 2,000 pounds of salt for every acre foot of water. You can use conversion factors in Table 2 to make this calculation for other water EC levels.

\*dS/m at 25ºC=mmhos/cm

24 Water Quality, Soil and Managing Irrigation of Crops

iii. use of wastewater as nutrient source (Bouwer & Chaney, 1974; Vazquez- Montiel et al., 1996) associated with mineral fertilizer savings and high crop yields (Feigin et al., 1991;

Irrigated agriculture is dependent on an adequate water supply of usable quality. Water quality concerns have often been neglected and the situation is now changing in many areas. To avoid problems when using these poor quality water supplies, there must be sound planning to ensure that the quality of water available is put to the best use. The objective of this article is to help the reader in better understanding of the effect of water quality upon soil and crops and to assist in selecting suitable alternatives to cope with potential water quality related problems that might reduce production under prevailing conditions of use. Thus knowledge of irrigation water quality is critical in understanding management for its long-term usage and productivity. Conceptually, water quality refers to the characteristics of water that will influence its suitability for a specific use, i.e. how well the quality meets the needs of the user. Quality is defined by certain physical, chemical and biological characteristics. Even a personal preference such as taste is a simple evaluation of acceptability. For example, if two drinking waters of equally good quality are available, people may express a preference for one supply rather than the other; the better tasting water becomes the preferred supply. In irrigation water evaluation, however, the emphasis is placed on the chemical and physical characteristics of water and only rarely is any other factor considered important. There have been a number of different water quality guidelines related to use of wastewater in agriculture. Each has been useful but none has been entirely satisfactory because of the wide variability in field conditions. The guidelines presented in this paper have also relied on previous ones but are modified for evaluating and managing

Soil scientists use various physico chemical parameters to describe irrigation water effects on crop production and soil quality. These include, Salinity hazard - total soluble salt content, Sodium hazard - relative proportion of sodium to calcium and magnesium ions, pH - acidic or basic, Alkalinity - carbonate and bicarbonate, Specific ions: chloride, sulfate, boron, and nitrate. However, another potential irrigation water quality parameter that may affect its suitability for

The most influential water quality guideline on crop productivity is the water salinity hazard as measured by electrical conductivity (ECw). The primary effect of high ECw water on crop productivity is the inability of the plant to compete with ions in the soil solution for water a condition known as Osmotic drought (physiological drought). Higher the EC, lesser is the water available to plants, even though the soil may appear to be wet. Because plants can only transpire "pure" water, usable plant water in the soil solution decreases dramatically as EC increases. An actual yield reduction from irrigation with high EC water varies substantially. Factors influencing yield reductions include soil type, drainage, salt type, irrigation system and management. The amount of water transpired through a crop is directly related to yield; therefore, irrigation water with high ECw reduces yield potential (Table 1). Beyond effects on the immediate crop is the long term impact of salt loading

agricultural system is microbial pathogens, which has often been neglected.

Tak et al., 2010).

water quality-related problems of irrigated agriculture.

**2. Irrigation water quality criteria**

**2.1 Salinity hazard /electrical conductivity**

1Leaching required at higher range.

2Good drainage needed and sensitive plants may have difficulty at germination.

Table 1. General guidelines for salinity hazard of irrigation water based upon conductivity.

Salt-affected soils develop from a wide range of factors including: soil type, field slope and drainage, irrigation system type and management, fertilizer and manuring practices, and other soil and water management practice. However, the most critical factor in predicting, managing, and reducing salt-affected soils is the quality of irrigation water being used. Besides affecting crop yield and soil physical conditions, irrigation water quality can affect fertility needs, irrigation system performance and longevity, and how the water can be applied. Therefore, knowledge of irrigation water quality is critical to understanding what management changes are necessary for long-term productivity.

Electrical conductivity (EC) is the most convenient way of measuring water salinity. EC is determined as the reciprocal of the specific resistance (ohms.m) of the water sample corrected to a standard temperature, usually 25°C.The basic unit of EC in SI units is Siemens m-1 (previously mhos m-1). Formerly water salinities were expressed in micro mhos cm-1.

Some useful conversions are: 1 mS m-1 = 0.01 m mho cm-1 =10 mµho cm-1

e.g. a water may have EC = 2000 µmho cm-1 = 2 mmho cm-1 = 200 mS m-1

Frequently EC is multiplied by a factor to obtain total soluble salts (mass/volume) as an expression of salinity. There is however no unique factor that can be applied and the factor will vary with composition and concentration. Factors found for W.A. waters vary between 5.0 and 8.5 (EC in mS m-1). Generally it is more convenient to use electrical conductivity as the measure of salt content as criteria are usually published in this form. Other terms that laboratories and literature sources use to report salinity hazard are: salts, salinity, electrical conductivity (ECw), or total dissolved solids (TDS). These terms are all comparable and all quantify the amount of dissolved "salts" (or ions, charged particles) in a water sample. However, TDS is a direct measurement of dissolved ions and EC is an indirect measurement of ions by an electrode. Although people frequently confuse the term "salinity" with common table salt or sodium chloride (NaCl), EC measures salinity from all the ions dissolved in a sample. This includes negatively charged ions (e.g., Cl- , NO-3) and positively charged ions (e.g., Ca++, Na+). Another common source of confusion is the variety of unit systems used with ECw. The preferred unit is deciSiemens per meter (dS/m), however millimhos per centimeter (mmho/cm) and micromhos per centimeter (µmho/cm) are still frequently used. Conversions to help you change between unit systems are provided in Table 2.

Effluent Quality Parameters for Safe use in Agriculture 27

SAR is a measure of the tendency of the irrigation water to cause the replacement of calcium (Ca) ions attached to the soil clay minerals with sodium ions (Na). Sodium clays have poor structure and develop permeability problems. The Residual sodium carbonate (RSC) is the measure in milli equivalents per litre (meq/L) of the excess of carbonates (CO3) and bicarbonates (HCO3) over magnesium (Mg) and calcium (Ca). With high RSC (>1.25) there is a tendency for Ca and Mg to precipitate in the soil, thus increasing the proportion of Na and

Potential for Water Infiltration Problem

\*Modified from Ayers and Westcot. 1994. Water Quality for Agriculture, Irrigation and Drainage Paper

Table 3. Guidelines for assessment of sodium hazard of irrigation water based on SAR and

The acidity or basicity of irrigation water is expressed as pH (< 7.0 acidic; > 7.0 basic). The normal pH for irrigation water ranges from 6.5 to 8.4. High pH's above 8.5 are often caused

Calcium and magnesium ions become insoluble due to high carbonates and bicarbonates thereby leaving sodium as the dominant ion in solution. As also described in the sodium hazard section, this alkaline water could intensify the impact of high SAR water on sodic soil conditions. The main use of pH in a water analysis is for detecting an abnormal water. The normal pH range for irrigation water is from 6.5 to 8.4. An abnormal value is a warning that the water needs further evaluation. Irrigation water with a pH outside the normal range may cause a nutritional imbalance or may contain a toxic ion. Low salinity water (ECw < 0.2 dS/m) sometimes has a pH outside the normal range since it has a very low buffering capacity. This should not cause undue alarm other than to alert the user to a possible imbalance of ions and the need to establish the reason for the adverse pH through full laboratory analysis. Such water normally causes few problems for soils or crops but is very corrosive and may rapidly corrode pipelines, sprinklers and control equipment. Any change in the soil pH caused by the water will take place slowly since the soil is strongly buffered and resists change. An adverse pH may need to be corrected, if possible, by the introduction of an amendment into the water, but this will only be practical in a few instances. It may be easier to correct the soil pH problem that may develop rather than try to treat the water.

Irrigation water SAR Unlikely Likely

0-3 >0.7 <0.2 3-6 >1.2 <0.4 6-12 >1.9 <0.5. 12-20 >2.9 <1.0 20-40 >5.0 <3.0

ECw\* (dS/m)

29, rev. 1, Food and Agriculture Organization of the United Nations, Rome.

and all concentrations are in meq/L

SAR = Na

increasing the SAR of the soil solution.

ECw2.

**2.3 pH and alkalinity**

by high bicarbonate (HCO3

0.5 (ca m g)

Table 2. Conversion factors for irrigation water quality laboratory reports. Source: Bauder *et al*., 2011

Definitions

#### **2.2 Sodium hazard/SAR**