law for all municipalities of the state of tataulipas. the next stage would be built a pumping station in "la pedrera" and the facility must be finished this year. colombia the main regulator norm for water management is the decree 1594 of 1984, which normalizes water usages and wastewater disposal through the country. the decree establishes water quality standards, which are guides to be used as a basis for decision making in assignation of water uses and determination of water characteristics for each application. water discharging parameters to public sewage are described in chapter vi of this decree. also, it was considered the resolution 3957 of 2009 to enlarge the water parameters comparison in colombia. this resolution establishes the technical norm, for wastewater discharges management and control in public sewage for the capital district. case description a report published by the national university confirms the presence of lead, cadmium, mercury and arsenic in plants watered with the polluted water of the bogotá river. according to it, vegetables have high levels of heavy metals that can be dangerous for human health. for the regional autonomous corporation (car) this is due to industrial downloads. in general, levels found in water, soil and vegetables of this area are much higher than the limits allowed by the world health organization. the authors, soacha y mosquera show figures much higher than the european union limits. in august 2008, the industrial firm "coca-cola femsa" was fined $111,000 usd due to its illegal discharge of industrial water in bogotá, as informed by the district environmental of the capital district of columbia. a technical report conducted by the aqueduct and sewer system of bogotá proved the existence of some waste water disposal that does not go through the company's treatment plant. the former administrative environmental department (dama) has given to the company an allowance for having a downloading point in october 2006, but the aqueduct and sewer system of bogotá found that place has already four discharge points, none of them registered or authorized. since january 2008, those four points were closed down and conducted to a treatment plant. venezuela the environmental organic law of venezuela gives the guidelines in terms of water management, as a duty of the state for the protection of watersheds. this in terms of classification and control of the quality of water bodies, control of effluent discharges or fluids susceptible of degrading the aquatic environment and alters the levels of quality required to preserve and improve the environment. the decree 883 follows these guidelines, being venezuela's national norm for water classification and control, created in 1995. the decree regulates the quality of water bodies and wastewater discharges. this law establishes the different types of water and the permissible parameters for water discharges in accordance to the final water use. wastewater discharging parameters to public sewer system are contained in section v of decree 883. paraguay the congress of paraguay created law 1614 of 2000 as the general regulatory and tariff framework for drinking water and sanitary sewer supply. following the law's guidelines, was created the quality regulation for drinkable water supply and sanitation, which applies to the entire country. this regulation includes in its title vi, all what refers to quality of the performance of sanitary sewer supply. in annex 10 are shown the maximum limits for physicochemical parameters, specifying discharge values for the type of wastewater treatment applied. summary table parameter units (daily) chile bolivia peru brazil ecuador argentina mexico colombia venezuela paraguay canada aluminium value (mg/l) 10 5 10 5 antimony value (mg/l) 1 0.5 arsenic value (mg/l) 0.5 1 0.5 1.5 0.1 0.5 0.75 0.5 0.5 0.5 1 barium value (mg/l) 5 5 0.1 bod5 value (mg/l) 33 – 50 80 250 250 200 200 800 350 250 300 boron value (mg/l) 4 5 cadmium value (mg/l) 0.5 0.3 0.2 1.5 0.02 0.1 0.75 0.1 0.2 0.2 0.7 carbonates value (mg/l) 0.25 chlorine (active) value (mg/l) 0.5 chloroform value (mg/l) 0.1 1 chrome (hexavalent) value (mg/l) 0.5 0.1 0.5 0.5 0.5 0.2 0.75 0.5 0.5 1 chrome (tetravalent) value (mg/l) 1 5 2 chrome (total) value (mg/l) 10 10 1 2 4 cobalt value (mg/l) 0.5 0.5 cod value (mg/l) 250–300 500 500 1500 900 600 copper value (mg/l) 3 1 3 1.5 1 15 3 1 1 2 cyanide value (mg/l) 1 0.2 – 0.5 1 0.2 1 0.1 1.5 1 0.2 0.2 fats and oil value (mg/l) 150 10–20 100 150 100 100 75 100 150 100 150 fluoride value (mg/l) 10 10 hydrocarbons value (mg/l) 20 20 50 20 20 100 iron value (mg/l) 1 15 25 10 25 5 lead value (mg/l) 1 0.6 0.5 1.5 0.5 0.5 1.5 0.5 0.5 0.5 1 manganese value (mg/l) 4 10 1 10 1 mercury value (mg/l) 0.02 0.002 0.02 1.5 0.01 0.005 0.015 0.02 0.01 0.01 0.01 nh3 – nh4+ value (mg/l) 80 4 80 40 niquel value (mg/l) 4 4 2 2 6 2 2 2 2 ph 5.5 – 9.0 6.9 6–8 6–10 5–9 5.5 – 10 5.5 – 10 5–9 6–9 5–9 phenolic compounds value (mg/l) 1 5 0.2 0.5 0.2 0.5 0.5 phosphorus value (mg/l) 10–45 10 15 20 10 10 selenium value (mg/l) 0.5 0.5 0.2 settleable solids ml/l 1 hour 20 8.5 20 20 0.5 7.5 10 1 silver value (mg/l) 1.5 0.5 0.5 0.1 sulphates (dissolved) value (mg/l) 1000 250 1000 400 400 sulphide value (mg/l) 5 2 5 1 1 1 1 2 1 surfactant mg/l 7 5 10 8 5 suspended solids (total) value (mg/l) 300 60 300 220 200 600 400 350 temperature °c 35 ±5 °c 35 40 40 45 < 40 < 40 40 40 tin value (mg/l) 2 4 vanadium value (mg/l) 5 5 zinc value (mg/l) 5 3 5 5 10 9 5 10 5 2 comparison analysis for purposes of having an idea of the requirements of the regulation, an index was created with the aim to rank the countries. this concept assumes that if a country has tighten limits than other, or if it declares explicitly a limit, then the regulation could be considered more stringent. this index takes in account all the parameters listed in the table, assuming the following criteria. if a country doesn't have any regulation, then it will get 1, from a scale of 10. if the country has the minimum limit it will get 10 points, if it has the maximum then it will get 5 points. later, an average is taken from all the parameters of the country, giving the index a relative position of all the countries. afterwards, all the values are classified using quartiles. a summary with the values of each country is presented below. chile bolivia peru brazil ecuador argentina mexico colombia venezuela paraguay index 4.5 5.3 5.3 4.3 6.8 4.0 3.6 5.9 6.3 5.0 quartile 2 3 3 1 4 1 1 4 4 2 ph the ph is a chemical parameter that measures the acidity or basicity of the water and is commonly measured in situ. distilled water has a ph of 7, where less than 7 is considered acid and greater than 7 is considered basic. in most cases, low ph is due to organic overloading and low oxygen conditions in the water. this characteristic is strictly controlled because it has a direct effect on water ecosystems and sewer systems materials. usually, ph standard is between 6 and 9 and can vary easily depending on the discharge content. in this case, peru was the country with the smallest range (6–8) and argentina and mexico were the ones with the widest range (5.5–10). no limit was found for canada regulation. settleable solids a low concentration of suspended solids in water or even complete removal after treatment is crucial to maintain water ecosystems development. high concentrations of suspended solids can slow down photosynthesis, reduce dissolved oxygen and increase water temperature. that is why suspended solids is a relevant parameter in wastewater discharge, that can be attributed to both industrial and domestic wastewater. when comparing wastewater regulations, it was found that bolivia has the strictest limit for this parameter (60 mg/l) while colombia presented the highest limit (600 mg/l). the value presented for colombia was extracted from the technical norm for wastewater discharges management and control in public sewage for the capital district. within these two limit values is shown a big difference among the two countries regulations for these standard, whereas for canada was encountered an average value of 350 mg/l. bod5 the bod5 standard is also an indicator of the presence of settleable solids in water, but specifically for organic matter. bod5 represents the amount of oxygen required by microorganisms to stabilize organic material present in wastewater. a higher concentration of bod5 means a high load of organic matter to be stabilized by microorganisms. chile has the stricter regulation for bod5 permitting wastewater discharges with a value between 33 and 55 mg/l. also, chile was the only country that presented a range for the limit of this parameter. by the other hand, colombia has the higher limit with 800 mg/l. in this case, is also taken the value from the capital district regulation, because there wasn't a specific value presented in the national norm, just said that bod5 removal must be greater than 80% for a new user. in comparison with canada and the other countries, chile's limit is a very strict value. arsenic arsenic is considered as a substance of sanitary interest and at the same time is one of the most toxic elements that exist. arsenic can be found naturally in the environment and also be an essential trace element for some animals. due to human activities, mainly through mining and melting, arsenic can now be found on many more places than where they existed naturally. world production of arsenic, in the form of its oxide, is around 50,000 tons per year. chile and mexico are primary exporters of arsenic. also, it is mainly emitted by copper producing industries, but also during lead and zinc production and in agriculture. arsenic can't be destroyed once it has entered the environment, which causes severe health effects on humans and animals. as mentioned before, chile and mexico are primary producers of arsenic and when checking arsenic limit values in their regulations aren't the more severe ones. mexico and brazil are the countries with a higher limit value and ecuador stays with the lower limit. as arsenic is also linked with agriculture; it is important to emphasize that the majority of the latin-american countries are characterized by having an agricultural economy. as a result, limit values encountered for arsenic in all the regulations varies from a small range of 0,1 to 1 mg/l. cadmium cadmium is also considered as a substance of sanitary interest. it can be found naturally in the environment and it always occurs in combination with zinc. in industry is a by-product of zinc, lead and copper extraction. it is also found in many manures and pesticides. cadmium can easily end up in soils and transported to surface waters when using manures and pesticides. regulations for cadmium are strict, and thus little cadmium enters the water through disposal of wastewater. the main producing country is of zinc is canada, with mexico and peru also being ones of the major suppliers. in the regulations comparison, cadmium standard was more severe in ecuador with an acceptance of 0,02 mg/l, whilst brazil was the laxer one with 1,5 mg/l. for the case of canada, mexico and peru, the latter has the stricter limit among them with 0,2 mg/l, while the other two remain in the average with 0,7 mg/l. cyanide cyanide, a substance of sanitary concern, is only present in wastewater due to use and discharge from the industrial sector. cyanide has severe effects both in human health and ecosystems. the severity of the harmful effects following cyanide exposure depends in part on the form of cyanide, such as hydrogen cyanide gas or cyanide salts. it becomes more dangerous when exposure concentrations are high. cyanide has been a major component of metal plating solutions and is mainly produced for the mining of gold and silver mining. in terms of latino-american regulations, argentina is the country that presents the harsher limit value