*Edited by Umar Bacha*

Rural health is the study of healthcare systems in rural settings. This book presents a comprehensive overview of rural health care and addresses such topics as human resources, maternal mortality in developing countries, safety of healthcare workers, zoonotic and veterinary diseases, and much more. Chapters include case studies and research in the field of rural health.

ISBN 978-1-83969-370-0

Rural Health

Published in London, UK © 2022 IntechOpen © Pongasn68 / iStock


**1.2 Suspension system**

contact of joints 1 and 4) and three prismatic joints *P*, two that represent tyres of the

The mechanism of **Figure 5a** has 2-DoF, and it requires two actuators to control its movement. The mechanism has a passive actuator in each prismatic joint of tyres (2 and 5—axial deformation); these actuators control the movement along the *x-*

In this model, the revolute joint (3) and the prismatic joint (4) can be changed by a spherical slider joint (*Sd*), with constraint in the *z*-axis, as shown in **Figure 6**.

The movement of this system is orientated by the forces acting on the mechanism (trailer weight (*W*) and the inertial force (*may*)) [13]. These forces affect the

þ *lr* ≈ �*FTi* þ *Fstart*

ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi *t* 2 *i*þ1 þ *l* 2 *i*þ1

� � q

*t* 2 *i*þ1 þ *l* 2 *i*þ1

q

ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi

0

B@

where *δT* is the normal deformation of the tyre [14], Δ*F* is the algebraic change in the initial load, *kt* is the vertical stiffness of the tyre, *ac* is the regression coefficient, *FTi* is the instantaneous tyre normal load, *li* is the instantaneous dynamic

vertical stiffness, *lr* is the initial dynamic rolling radius of tyre *i*, *ti* is the track width,

*zi kT*

1

*δi* ¼ *arcsin li sin βi* ð Þ ð Þ*=ti* (4) *θi* ¼ *θ j* ¼ 90 � *δi* � *βi* (5)

*zi* is the initial normal load *i*, *kT* is the equivalent tyre

*li cos βi* ð Þ

þ *lr* (1)

(3)

CA (2)

system (2 and 5), and one the lateral slide of tyre 2 (3).

*Numerical and Experimental Studies on Combustion Engines and Vehicles*

passive actuators of the mechanism, as shown in **Figure 7**. Eqs. (1)–(5) define the kinematics of the tyres system.

*li* ¼ *δT* þ *lr* ¼ 3Δ*F*

*kt* þ *ac*

*βi* ¼ 90 � *arcsin li*þ1 ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi

and *z*-axes, as shown in **Figure 5b**.

*ti* ¼

rolling radius of the tyre *i*, *Fstart*

**Figure 6.** *Tyres system model.*

**Figure 7.**

**134**

*Movement of tyres system.*

*t* 2 *i*þ1 þ *l* 2 *i*þ1 þ *l* 2 *i* � 2

s

*1.1.2 Kinematics of tyre system*

This system comprises the linkage between the sprung and unsprung masses of a vehicle, which reduces the movement of the sprung mass, allowing tyres to maintain contact with the ground, and filtering disturbances imposed by the ground [3]. In heavy vehicles, the suspension system most used is the leaf spring suspension or rigid suspension [15], as shown in **Figure 8**. For developing this model (trailer), it is assumed that the vehicle has this suspension on the front and rear axles.

The rigid suspension is a mechanism that allows the following movements of the vehicle's body under the action of lateral forces: displacement in the *z-* and *y*direction and a roll rotation about the *x*-axis [1, 8], as shown in **Figure 9a** and **b**.


**3. The major objectives of the study**

#### **3.1 The major objectives of the studies are as follows**

The first objective is to study the tourism potentials of Bhitarkanika. The second objective is to identify different flora and fauna of this place with special emphasis on conserving endangered species. The next objective is to examine the role of government in the conservation and preservation of eco-tourism resources. The last but not the least objective is to analyse how to promote and market Bhitarkanika as a perfect eco-tourism destination.

### **4. Scope of the study**

The current study on Bhitarkanika Wildlife sanctuary and National Park does not only provide you with the scope for getting knowledge on different flora

*Development of Eco-Tourism Vis-à-Vis Conservation Measures for Protecting the Endangered… DOI: http://dx.doi.org/10.5772/intechopen.102502*

and fauna available inside the sanctuary but also study the scope of promoting Bhitarkanika as an important eco-tourism destination in entire eastern India with special emphasis to the state of Odisha. Here in this study, the author has considered Estuarine crocodile (Salt Water Crocodile) and Olive Reedley Turtle as major endangered species inside the sanctuary in terms of conservations of fauna, which needs to be conserved and protected. However, in terms of flora, the author considers the mangrove trees as an endangered species in Bhitarkanika, which needs to be protected in order to save the sanctuary and market this destination as a perfect eco-tourism place for the state of Odisha.


**10. Efficiency of phagocytosis**

Many phagocytes have a relatively low phagocytosis capacity at rest and when inflammation gets in, phagocytes get exposed to a variety of activating stimuli which increase the efficiency of the cell to phagocytose. The activating stimuli include, bacterial products, cytokines and inflammatory mediators, the signals induced by these substances lead to increased activation of molecules involved I phagocytosis e.g. leukotrieneB4 increases Syk activation and consequently antibody dependent phagocytosis [49]. Also the action of P13K and ERK, which are essential enzymes for bacterial peptide, glanulocyte colony stimulating factor, leukotrienes and cytokines such as interleukin [50]. Phagocytosis can be regulated by cell differentiation, e.g. monocytes have lower phagocytic capability than neutrophils and macrophages, however they can enhance their phagocytic capacity after cell differentiation [51]. The capacity of monocytes to phagocytose diverse targets alter with the state of differentiation. Therefore during monocyte to macrophage differentiation the e most important signaling enzymes are reorganized in order to achieve increased phagocytosis [51, 52].

*Functioning and Control of Phagocytosis DOI: http://dx.doi.org/10.5772/intechopen.110511*


(3) Aging

Aging has relatively little effect on the low temperature performance of porous asphalt mixture. The factors of porosity and aging are together the least and the second-least influential among the four factors. From Figure 9, it can be seen that the flexural tensile strength, maximum bending strain, and bending stiffness modulus of porous asphalt mixture with short-term aging are respectively 0.9%, 1.1%, and 0.5% lower compared to those of porous asphalt mixture with no aging. The flexural tensile strength and bending stiffness modulus of porous asphalt mixture with long-term aging are respectively 4.4% and 6.2% lower whereas the maximum bending strain is 0.4% higher, compared to those of porous asphalt mixture with no aging. The modest decrease in low temperature performance of porous asphalt mixture through aging was in line with the findings by Ma et al. [45]. The slight effect of aging should be due to the effectiveness of the high viscosity SINOTPS modifier in improving the antiaging performance of porous asphalt mixture.

### (4) Test temperature

The influence of test temperature on low temperature bending test results is less significant than that of modifier content. At this juncture, it is noteworthy that the brittle point is a threshold temperature of asphalt mixture at which its behaviour is transitioned from plastic to brittle. In low temperature bending test, in order to prevent possible sudden brittle fracture from affecting the accuracy of the results, the test temperature is generally set at higher than the brittle point temperature. For porous asphalt, the brittle point is lower than that of ordinary dense graded asphalt [57], and the test temperature can generally be set at −10 ◦C to −20 ◦C. Consequently, in order to investigate the effect of temperature changes on the low temperature performance of porous asphalt mixture, three levels of test temperature, namely 0 ◦C, −10 ◦C, and −20 ◦C, were adopted in the test.

From Figure 9, it can be seen that when the test temperature was decreased from 0 ◦C to −20 ◦C, the flexural tensile strength increased by 5.0%, the maximum bending strain decreased by 7.7%, and the bending stiffness modulus increased by 13.9%. The results indicated that in this temperature range, the porous asphalt mixture still exhibited plastic deformation, and the brittle point temperature was not reached [58]. The maximum bending strain decreased with the test temperature, indicating that the lower the test temperature, the less capable the porous asphalt mixture in resisting deformation. At the same time, the bending stiffness modulus of porous asphalt mixture increased with decreasing test temperature, indicating a reduction in the low temperature crack resistance of porous asphalt mixture.

### *3.3. Influence of Porosity on Maximum Bending Strain*

The porosity is amongst the most concerned indicator in the design of porous asphalt mixture. To further analyze the influence of porosity on the low temperature performance of porous asphalt mixture, the single factor influence test of porosity was conducted. The test selected the maximum bending strain as the evaluation indicator.

The experiment adopted the same mineral aggregate gradation and raw materials as those in the orthogonal test, the modifier content was 12%, and the bitumen/aggregate ratio was 4.8%. The mixing and moulding process of porous asphalt mixture was consistent with that in the orthogonal test, and the porous asphalt mixture was not subjected to aging. According to the results analysis of orthogonal test, as the porosity increased from 16.2% to 23.8%, the maximum bending strain decreased by 3.3% only. To attain higher statistical confidence, in the single factor influence test of porosity, on the basis of the orthogonal test results, another two groups of specimens with porosity of 18.4% and 26.3% were added. The five groups of specimens were subjected to low temperature bending test at −10 ◦C. With reference to the test results, the relationship between the maximum bending strain *εB* (in με) and the porosity *n*0 (in %) was obtained, as depicted in Figure 10.

**Figure 10.** Relationship between maximum bending strain and porosity.

It is evident from Figure 10 that there exists an approximately linear correlation between the maximum bending strain and the porosity of porous asphalt mixture, and the maximum bending strain decreases as the porosity increases. The relationship between the maximum bending strain and the porosity is expressed in Equation (2) with coefficient of determination *R*2 = 0.986.

$$
\varepsilon\_B = 7527.7 - 100.9n\_0 \quad (16.2 \le n\_0 \le 26.3) \tag{2}
$$

when designing the mix proportion of porous asphalt mixture, in order to ensure good working performance of porous asphalt mixture in low temperature environment, the porosity should also conform to the required limits of the maximum bending strain in relevant technical standards. In the cold regions of northern China, when applying porous asphalt pavement, the maximum bending strain of porous asphalt mixture should not be less than 5000 με in accordance with JTG F40-2004 [50]. From Equation (2), it is noted that when the porosity is controlled within 25%, thus the limit requirement on maximum bending strain is satisfied.

Finally, the possible use of recycled asphalt pavement to enhance the sustainability of highway infrastructure has attracted vast research interest in recent years [59–61]. Recycled asphalt mixtures, which are prepared by blending reclaimed asphalt pavement, virgin bitumen, and mineral additives, offer various advantages including resources recycling, cost saving, and reduced environmental impact [62]. Further research on the utilization of reclaimed asphalt in porous asphalt pavements and their low temperature performance is recommended.


**2. Indications for enteral nutrition**

Optimal hydration and nutrition is required to meet the body's daily nutritional requirements. Patients with dysphagia may be unable to attain these minimum nutritional requirements with oral intake and require enteral nutrition [2-9]. These patients include those who are unable to swallow due to neurological damage or degeneration [4, 10-15], or those who have structural abnormalities that make oral nutrition impossible, as in the case of patients with advanced stage head and neck cancer or oesophageal cancer [16-18].

© 2015 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

The most common indicator for long term enteral nutrition is a cerebral vascular accident (CVA) [3, 5, 10-12, 19-26]. Dysphagia with resulting malnutrition and/or dehydration is common in patients who have had a CVA, explaining the high need for enteral nutrition within this population [10, 13, 27-28]. Patients with other neurological deficits such as traumatic head injury or neuro-degenerative diseases, may also require short or long term enteral nutrition as a safe method of hydration and nutrition [7, 29-33].

Certain medical conditions are more likely to predispose patients to require enteral nutrition because of concomitant dysphagia and increased nutritional needs. Patients with head and neck cancer may develop dysphagia after radiation treatment as a result of tissue damage to the swallow mechanism [18] with a resultant need for prophylactic enteral nutrition [17]. Those patients who continue on oral intake may require enteral nutrition as a supplement to ensure sufficient intake of the daily nutritional requirements while receiving radiotherapy [18]. In cases of trauma to the body or after surgery, enteral nutrition is also recommended to aid sufficient caloric intake to minimise loss of body fat and to support recovery [15, 29, 31-32, 34-35].


Safe Drinking Water: The Need and Challenges in Developing Countries

*Collins Onyebuchi Okafor, Ude Ibiam Ude, Felicia Ngozi Okoh and Blessing Osose Eromonsele*

## **Abstract**

Safe or potable water is water which quality is suitable for human consumption both for drinking or cooking purposes. Safe and potable drinking water is an inevitable factor for a robust healthy society, but clean water for drinking and domestic purpose still remains inaccessible to 1.1 million people on a global scale. The importance of potable water can never be overestimated because of its benefits of providing a number of useful services for humans and the ecosystem. Water contributes directly and indirectly to the GDP of a country when tailored properly. While the majority of the population in developing countries lives in cities, supply and access to safe drinking water in sufficient quantity and quality for all urban dwellers sits at a crossroads between environmental issues. For instance the issue of available freshwater resources, and development issues, through the implied social, economic and sanitation challenges still remain unsolved. In order to achieve quality drinking water in fostering human development, some vital issues that pose challenges must be taken into good consideration. This chapter has discussed safe drinking water in view of its benefits and challenges as it affects developing countries.

**Keywords:** water, quality, health, benefits, challenges

## **1. Introduction**

Water is safe and fit for drinking as a result of been free from biological (pathogenic microorganisms), physical (debris and impurities) and chemical (toxins, carcinogens and radionuclide) contaminants or other health hazards. For water to be drinkable, it must be devoid of unpleasant tastes, odors and colors and maintained at a reasonable and acceptable limits of temperature. In order to satisfy the increasing demand for safe and potable water supply, the cleanest sources of surface water and groundwater must be preserved for such purposes. Potable water whether treated or raw (i.e untreated) should at least meet numerous physical, chemical, biological and microbiological standards [1, 2].

Safe and potable drinking water is an inevitable factor for a robust healthy society, but clean water for drinking and domestic purpose still remains inaccessible to 1.1 million people on a global scale. In developing countries, sources of drinking water ranges from surface water, groundwater (such as well water and borehole water), spring water, saline water, bottled water and harvested rainwater. The presence of opportunistic and obligate pathogens such as *Pseudomonas* spp*., Aeromonas* spp*., Klebsiella* spp*., Mycobacter* spp*.*, *Escherichia coli, Helicobacter* spp*., Salmonella* spp*.* and *Legionella* spp*.,* which may increase the health risks associated with the consumption of water, arises from these outlined sources. According to World Health Organization, the global estimate on death resulting from diarrhea as a waterborne disease exceeds 1milion annually, many of which have been linked to diseases acquired from the consumption of contaminated waters and seafood. In some countries, cases of water related diseases are inestimable because of lack or poor health data, inefficient treatment strategies and policy implementations. The challenge of maintaining potable and quality drinking water is the leading source of outbreaks of water related diseases across the globe. This calls for new approaches in the treatment of water meant for public consumption [3].

## **2. Benefits of safe drinking water**

Potable or safe drinking water is extremely important to human life and human development because water is a "sin qua non" for almost every human activities and indispensable for sustainable development. The negative impact of unsafe water over health, national productivity, quality of life and socio- economic development are enormous. This is because water is a decisive component in human survival with respect to security, socio-economic activities, which include transportation, agriculture, production, domestic and foreign consumption and maintenance of healthy ecosystems [4, 5].

Water is a lifeline of the biosphere and planetary life that requires adequacy, uniform distribution, reliability, equal accessibility, clean, safe and acceptability [6]. When safe and clean water is uniformly distributed and the demand for it remains lower than the available supply, it rapidly fosters exponential growth that support social and economic development, ensures national security, promotes and maintains healthy ecosystems across different spheres of life in many regions of the world [4, 7]. When the quality of water is satisfactory, it becomes a fundamental indicator of good public health, societal well-being and a crucial element for rapid development of a country. On the other hand when water is contaminated, it becomes a vehicle of diseases and a potential to threat to human, thus affecting individual productive rate [8, 9].

According to the WHO [10], about 1.1 billion people consume unsafe water across the globe contributing to about 1.7 million global death annually (approximately 3.1%) with a potential annual disability burden of 54.2 million (~3.7%). This calls for the provision of safe water and basic water related sanitation and hygiene practices. In developing countries, the benefit of safe and potable water is not sufficiently documented as a result of poor or nonexistent government interest for water related issues and low level of investment in water treatment and distribution infrastructures. It may interest you to know that from little information gathered in these countries, water contributes immensely to the little leap experienced by their staggering economic development. In developing continents like Africa and Southern America, water alone contributes significantly to their economy with a very high benefit-cost ratio of more than 5:1 due to its intertwined connection with industrialization, agriculture/food and energy production, whereas in some other countries, it may be as high as 7:0 but with a minimal recorded of 2:0 across the globe. This mean that if

#### *Safe Drinking Water: The Need and Challenges in Developing Countries DOI: http://dx.doi.org/10.5772/intechopen.108497*

developing countries pay maximum attention to ensuring adequate management of water resources, there will be a resultant gain in economy ranging from 5 to 30 USD per 1USD investment beside other technical, environmental and political gains [9, 11]. Apart contributing to economic development, the water sector is extremely important in the development of other aspect of national growth because of its interconnected relevance with other developmental sectors such as the household, health, agriculture and food, energy and power, industry and manufacturing, environmental, educational, legal and political at local, national, regional and international levels [12].

When sources of potable water such as rivers, aquifers, and underground waters rivers become heavily polluted, downstream regions usually experiences loss in economic growth ranging between 0.8 and 2.0 percent of economic growth. This is because economic growth and water pollution are intrinsically related. Inasmuch as quality water improves national economy, declining water quality can impact the economy in various ways across the health sector where labour productivity can be adversely affected, agricultural sector in terms reduction in quality and quantity of food produced, tourism, real estate, aquaculture/fisheries and other sectors which rely on environmental quality and ecosystem services. Irrespective of these wellknown impacts, estimating the impact of water quality on economic activity can be very slippery. Therefore is a need to fill this gap by using a run-of-the-mill practical approach in modern environmental economics and new data on economic activity and water quality. Because water is always needed for life, health, and economic production, the impurities generated by predicate polluters may affect succeeding users [13]. Undoubtedly, access to potable water has series of direct and indirect benefits with respect to health, education, poverty and environment as there exist a connecting nodes between water and sustainable development, far beyond its social, economic and environmental dimensions because safe water plays a significant role in addressing the developmental challenges, such as human health, food and energy security, urbanization and industrial growth, as well as climate changes [14].

In the past two decades, about 2.3 billion people have gained access to an improved drinking water indicating a monumental gain, but there's a lot to be done however, this success is somewhat teetering as many of developing countries, especially the poor ones are still battling to get access to potable as research has shown that the most of the people without access to safe water are from developing nations implying many people in the developing world, especially Africa, still depend on unsafe water sources for daily water need and affected by chronic water problems and water-borne diseases [15–18]. Notwithstanding, safe (potable) water remain the main developmental pillars of national development that should be embraced by the developing countries.

## **3. Challenges of safe drinking water in developing countries**

Several factors are germane to ensuring the availability of potable water with respect to the increasing demand by the growing population. The factors that are key interest in this chapter include availability and scarcity, contamination, portability, accessibility and affordability, sustainability and climate change.

#### **3.1 Contamination**

Contamination of natural waters represents one of the main risks to public health, a fact that is directly related to the discharge of untreated domestic, hospital, and

industrial effluents, which cause contamination of aquatic bodies through pathogenic microorganisms such as bacteria, viruses, protozoa, and helminth eggs that are contained in them [18]. Bacterial contamination of water resources coupled with other contaminants such as nitrates, metals, trace quantities of toxic materials and salts are the greatest threat to safe drinking water. The presence of opportunistic pathogens such as *Pseudomonas* spp*., Aeromonas* spp*., Klebsiella* spp*., Mycobacter* spp*.*, *E. coli, Helicobacter* spp*., Salmonella* spp*.* and *Legionella* spp*.* that may increase the health risks associated with the consumption of water arises from these sources and should be checkmated [3, 19–22].

 On a global estimate, more than 25,000 people (comprising about 5000 children) die daily from water related diseases of which most of these diseases can easily prevented if safe drinking water tops the scale of preference among leaders across the world. In most developing countries, waterborne diarrhea and other related water diseases kill about 1.8 million children per year representing the leading cause of death globally. Indicators of fecal contaminated water (i.e coliform bacteria) are ingested by almost 1.8 billion people through feacally contaminated water. In order to achieve the goal of making water safe for drinking, removal of contaminants must be a regular normal. Access to safe water entails the reduction of water-related diseases and serves as an opportunity for improved health because of it potential reduction of the outbreak of health hazards [9].

More than 5 million people die yearly from water associated disease. More than 50 percent these waterborne diseases are of microbial origin, having cholera with highest prevalence. The source of microorganisms in water sources is usually from waste water discharge into fresh waters and coastal waters. The contamination of water bodies is a regular muddle across the globe. These contaminations may be environmental or anthropogenic in nature. Higher levels of contaminants in drinking water are seldom to cause acute health effects. Of course it depends on individual susceptibility and mode of contact with the body. The microbiological examination of water is used naturally and scientifically worldwide to monitor and control the quality and safety of drinking waters [23, 24].

Some contaminants can be easily identified by assessing color, odor, turbidity and the taste of the water. However, most cannot be easily detected and require testing to reveal whether water is contaminated or not. Thus, the contaminants may result in unappealing taste or odor and staining as well as health effects. Color of the drinking water is a physical characteristic that cannot be noticed unless it is one of high concentration [25].

Groundwater contamination may occur as a result of the types and concentrations of natural contaminates. The nature of these contaminates depend on the type of the topographical materials along the flow path of the groundwater and the quality of the recharge water. For instance groundwater flowing via sedimentary rocks and soils may pick up a wide range of chemical contaminants (magnesium, calcium, and chloride, arsenate, fluoride, nitrate, and iron) in concentrations exceeding the recommended level becomes unacceptable for water meant for drinking and domestic purposes. Although, the impact of natural contamination of groundwater depends on the types and concentrations of the contaminants, when they occur in water at unacceptable levels will definitely render the water unfit for drinking [26]. Man-made water contaminants arise from by-products of household, industry and agricultural practices. These pollutants include heavy metals such mercury, copper, chromium, lead, and hazardous chemicals, dyes and compounds like insecticides and fertilizers and they represent a significant group of groundwater contaminants [25].

#### **3.2 Portability**

Potable or drinking water is that which has its bacteriological, chemical and physical properties at acceptable levels thereby making it safe for drinking, cooking and other domestic purposes. Countries differ with their actual guidelines for quality water. This disparity contributes to the major challenges that developing countries has in ensuring potable drinking water [27]. The Guidelines seeks measure to support the development and risk implementation strategies that may ensure the provision of potable drinking-water through the management of unsafe constituents of water. These strategies may embrace national or regional standards developed from the scientific basis provided within the pointers. The guidelines are rules that describe minimum requisite of safe practice to guard the health of water end-users in order to derive numerical "guideline values" as pointers of constituents of water or indicators of water quality.

In order to outline obligatory limits, it's desirable to appraise the guidelines within the milieu of native or national, environmental, socio-economic and racial or ethnic conditions. The foremost reason for not advocating the adoption of international standards for drinking-water quality is the primacy provided by the inclusion of a risk–benefit approach (qualitative or quantitative) within the institution of national standards and laws. Further, the Guidelines for safe water practices are best carried out through associate degree integrated pre-emptive management substructure for safety applied from abstraction to end-usage. The guidelines offer a scientific locus of departure for national authorities to develop drinking water laws and standards applicable for the national state of affairs. In developing standards and laws, care ought to be taken to make sure that meager resources are not unnecessarily misappropriated (as the case with many developing countries) to other unproductive projects of national need quite unrelated or comparatively of minor importance to public health [28].

The approach in accordance with these guidelines is meant to steer to national standards and laws that may be promptly engaged and enforced to safeguard public health. The framework and methods of drinking-water guidelines could vary among countries and regions creating substantive gaps between developed countries and developing countries. This is because there's no single approach that's universally applicable. It is crucial within the development and execution of standards that the present and planned legislation with respect to water, health and native or local government are taken into consideration and that the tenacity to develop and enforce regulatory laws is assessed. Considering the unique political gaps and technological advancement within third world countries, different and workable approaches need to be test run and implemented when proven reliable. This is because standards that may work in one country or region may or may not be applicable in another country or region(s) owing to the fact that the assessment of safety of what the acceptable limits or risks are is peculiar to circumstances and is also a function of which society in part or as a whole has a functional role to play. It is therefore imperative that every country review its needs and abilities in developing a characteristic framework for water quality. Drinking water guidelines specifies maximum acceptable values/limits for a number of contaminants in drinking water. These values/limits are presented for minimum concentrations of microbial contaminants such bacteria, viruses, and parasites; chemical contaminants of health importance including both specific inorganic and organic constituents, pesticides, disinfectants, and disinfection byproducts; radioactive elements and substances and parameters in drinking water that may give rise to complaints from end users The ultimate judgment on whether or not the profit

ensuing from the adoption of any of the rules and guideline values as national or local standards accounts for the cost is for every country to determine [27, 28].

Making water safe and potable is a big challenge in developing countries. To make water potable, it is usually put through to one or more treatment processes targeted at removing impurities in order to improve its portability and/or its pleasing quality. Various treatment processes exist for fresh water treatment. These include; coagulation, sedimentation, granular media filtration, adsorption, ion exchange, membrane filtration, slow sand filtration, and disinfection, and sometimes softening. Moreover, how these techniques and processes are applied in order to make drinking water more potable and safer in most developing nations is a major challenge because of lack of sufficient funds and other compounding economic issues. Potable drinking water must be among the highest priorities for every nation on earth because in recent times contaminated water kills more people than cancer, AIDS, wars or accidents and is mostly in developing nations. It is imperative that the water which humans drink be free of pathogenic organisms and toxic chemicals that constitute possible risk to public health. Moreover, developing countries constitute more than 70% of the world's human population technologies for making drinking water safe must be a pre-requisite in order to it accessible, affordable and environmentally sound, and as well geared towards becoming the nation's cultural norms [29].

Technological choices for fresh water treatment fall into two main categories – those that are used by urban authorities at clustered points from where water is then distributed, and those that are usually applied by individuals at homes even in rural areas. The most common and effective techniques for fresh water purification is chlorination. This is because this point-of- use (POU) water treatment strategy is cheap and easy to practice. But this is seldom rampant in most developing countries. There is a need for strong advocacy and serious engagement of this simple technology in the developing countries in order to curb the rising challenge of safe drinking water. Even under poor sanitary and hygienic conditions, in which people collect whatever water that is available from community tanks, wells, pumps and taps for use in their homes, if water is chlorinated, a dramatic decline in the incidence of water-borne diseases follows. Chlorination as a method has been in use for the treatment of public water supplies since the beginning of the twentieth century. The use of sodium hypochloride solution is a common method of chlorination that is used for the treatment of water in developing countries. The solution is placed in a capped bottle with directions for use. The user adds one full bottle cap volume of the solution to clear water (or two cups volumes for turbid water) to a standard-sized storage container. The user shakes the container and then waits 30 minutes before drinking. One major challenge of chlorination is the possible formation of carcinogenic disinfectant-by-products due to the presence of high organic components. But it's overwhelming popularity comes from the fact that it leaves a residual in the water matrix which helps in controlling possible re-growth of pathogenic microbes [30], although bacteria in drinking water distribution systems have devised a mechanism of evading chlorine disinfection through the formation of biofilm and acquisition of antimicrobial resistance elements [31].

In the island-cluster nation of Maldives, in the Arabian Sea/Indian Ocean, a technique has been developed that is cost effective and practicable at home by individuals for producing safe drinking water. This method is called solar water disinfection technique (or SODIS) with more than a dozen solar water disinfection techniques been perfected and put into practice. A process where sunlight and plastic containers are used to kill disease-causing organisms that contaminates water meant for domestic

#### *Safe Drinking Water: The Need and Challenges in Developing Countries DOI: http://dx.doi.org/10.5772/intechopen.108497*

purposes. An individual or family, village or community may choose the technique that is more suitable to its circumstances [29].

The role of solar disinfection of water has many prospects in developing countries because of economic issues in these countries. Solar disinfection (SODIS) method is the commonly used method because of its cost effectiveness for disinfection of water meant for oral rehydration solutions [32]. In this method, about 0.3–2.0 liters of plastic soda bottles is filled with low turbid water. It is then shaken to oxygenate the water. After shaking, the bottles are allowed to stand under the sun for 6 hours and 2 days for a cloudy weather [33]. Organisms that are sensitive to this method include bacteria and viruses, protozoans such as *Cryptosporidium* and *Giardia* [34]. The innovations of using direct sunlight to disinfect water has been widely applied and the results has always been positive [35, 36]. Several challenges affects the use of this method because despite its usefulness and advantages (cheap technology), the major limitation in using this system still remains the maximum trapping of the sunlight for such purposes as the designing of solar systems are not always easily affordable in developing countries. Another challenge is the seasonal and weather changing factors that affect the intensity of the ultraviolet light coupled with the length of time it takes to treat only small volumes of water. In high turbid waters, a pre treatment using flocculation, sedimentation or filtration is usually employed before solar disinfection in order to obtain a more accurate result [31].

In general, several factors compound the easy practice of water treatment in the developing countries. These challenges to effective drinking water supply in developing countries include the natural scarcity of water in certain areas, floods, climate change, stratification and aeration of abstraction points, poor access and poor resource management.

Flood gives rise to source-receptor issues by increasing the concentration of silt thereby causing more siltation problems in river systems as well as the contamination of rivers and large dams. Climate change and water scarcity are also some of the concerns [37, 38]. Breaking down the thermoclines during stratification is also a challenge in that it requires much energy during abstraction and aeration of the source. Poor water productivity in the agricultural sector can impact on water quality [39]. Easy affordability, investment into water infrastructure and quality storage facilities to prevent contamination is the issues that need to be addressed. This entail qualitative education and awareness campaign after serious cross-contamination of its prospect [40–42]. The most important aspect in the maintenance of clean drinking water in the developing countries is an integrated approach of various feasible ways for achieving adequate water that is safe for public use. Proper management of solid waste and waste water can enhance the quality of drinking water systems [43, 44].

#### **3.3 Availability & scarcity**

Another prevailing challenge to safe drinking water in developing countries is the issue of natural scarcity of fresh water sources in certain areas especially in sub-Saharan Africa. For instance, at different times of the year, the fresh water availability varies. For example rivers are predominantly used during the wet season while underground such as borehole or dug-well water sources are used during the dry season [31].

Safe drinking water is a not just a privilege but a birthright of every individual irrespective of social class because it is connected to every facet of life on earth. It is also a major criterion for a robust national growth. Thus to maintain a robust and healthy society, adequate, reliable, clean, accessible, acceptable and potable drinking water supply has to be available for everybody.

Two factors dominate the scarcity of safe drinking water in developing countries. These are physical and economic scarcities. In some countries, *physical scarcity* where sufficient freshwater is not available is a leading challenge while in some countries (e.g. Nigeria, Ethiopia, Congo and Papua New Guinea, Ethiopia) where economic scarcity is the key challenge, abundant freshwater is available, but it is expensive to use. The other challenge is the fast increase in world's population and shifting demography at an alarming rate, whereas the available freshwater resources seldom change but almost remain constant [9].

Although environmental factors contribute to the issue of water scarcity, it is compounding because it may be mostly anthropogenic (man-made). More than two-thirds of the earth's surface is covered with water, but mostly exist as sea water and undrinkable unless desalinated. Only about 2.7% of this water is available as freshwater in lakes, brooks, ponds, stream, springs, groundwater and rivers on earth with only accessible proportion of 1%. This is because most of the available freshwater resources are inaccessible existing deep aquifers or frozen in the polar ice regions accounting for the very small proportion of safe drinkable water on earth (~3%) in the freshwater resources.

The issue of water scarcity in the third world is an ugly display of poor governance. Africa as continent should be the least with safe water challenge across the globe. With exemption of some water stressed countries such as South Africa, Morocco, Libya, Egypt, Niger, Tunisia, Algeria, Djibouti, Namibia, Sudan etc., other African countries with excess freshwater resources (e.g. Nigeria, Ethiopia, Congo and Papua New Guinea) still suffer from unavailability of adequate potable or safe drinking water due to economic reasons. South Africa receives about 450 mm annual rainfall and is classified as a water-stressed country with available freshwater resource that can only sustain 80 million people [45, 46]. On the contrary, Ethiopia being the second populous countries in Africa with more than eight river basins serving as the water tower of the whole east Africa due to the availability of surplus freshwater still struggles with count as the country among nations affected by long-standing water problem. The major cause of water scarcity in the world is further exasperated either by reduced water volume per area or the increasing demand for water due to population growth and the repudiating water quality by pollution [9].

There are two key factors over which the global concerns for the future availability of freshwater (safe drinking water in particular) centers on. They are the dramatic increase in the total withdrawals of freshwater in recent times and the incessant rise in the world's population across the globe especially in the developing countries. Currently, groundwater aquifers are undergoing repeated depletion even faster than they are been replenished in most parts of China, India and United States. This situation is mainly caused by unbalanced irrigation practices that not only plays significant role in groundwater exhaustion but in the degradation of soil quality thus reducing agricultural productivity making these region to be prone to future food insecurity and placing the future goal of 'green revolution' at jeopardy. Over the past 4-5 decades, freshwater withdrawals have doubled across the globe.

In the 3–10 years, the world population is estimated to reach 8–9 billion with a 1.5 billion projected yearly increase within the next 25–30 years. This will automatically reduce the availability of freshwater to 40% with respect to access to freshwater per person per year. As of date, reasonable number of the world's population (6 billion people) relies on freshwater supply and are currently facing water shortages. For

*Safe Drinking Water: The Need and Challenges in Developing Countries DOI: http://dx.doi.org/10.5772/intechopen.108497*

instance in 31 countries (most developing countries such as Botswana, China, Ethiopia, Haiti, India, Kenya, Nigeria, Peru and Yemen) they are presently about 2.8 billion people that are confronted with the challenge of severe water problems.

According to the report by World Resources Institute [47], about 17 countries namely; Qatar, Israel, Lebanon, Iran, Jordan, Libya, Kuwait, Saudi Arabia, Eritrea, UAE, San Marino, Bahrain, India, Pakistan, Turkmenistan, Oman, and Botswana as of 2019 comprising about 1.7 billion people (about a fourth part of the world's population) are confronted with "Extremely High" water stress challenges. This challenge predisposes more than 1 billion people to water scarcity crisis and may reach about 3.5 billion people before 2025. Twelve among these countries majorly located within the MENA (Middle East and North Africa) region were ranked based on their exposure to water stress drought, flood and drought risk which are basic factors that controls water availability. India with the leading population (1.4 billion) among these 17 countries is expected to take the lead the effort in forming alliance with the rest of the 16 counterpart countries to demystify this impending global crisis because a country with such huge population is most vulnerable to freshwater shortages. If these issues are not tackled headlong, these countries could be at jeopardy of huge economic crisis resulting from climate related freshwater scarcity. They may end up losing about 6–14% GDP by 2050.

The challenge of safe water scarcity has raised some level of panic across the globe both at the local and international level, underpinned by the United Nations Sustainable Development Goals 6 (SDG-6) geared at providing access to clean drinking water for all and highlighting its importance to hygiene and the prevention of diseases. Despite these, inequalities remain in accessing safe drinking water in the world [48] (**Figure 1**).

**Figure 1.**

*Countries with extremely high water stress [47].*

This challenge is worrisome because it has been observed that within a generation, the world's population may likely increase to about 8 billion people. But as we know, there is little or no significant rise in the amount of available freshwater as this population surges but will likely remain the same. It is as clear and enthralling as intact water thumbing down a mountain stream in a chain reaction. A novel approach must be taken in order to find new and objective ways of saving the situation by using and recycling the available freshwater at our disposal [29].

The problem of potable water shortage has become a source of concern in the world; locally and globally. Despite the concerted effort by the United Nations Sustainable Development Goals 6 (SDG-6) channeled at providing access to clean drinking water for all and underlining its import to hygiene and the prevention of diseases. Notwithstanding these efforts, inequalities remain in accessing safe drinking water in the world as more than 80 countries still suffer from water scarcity as it reflects on their public health and economic well being. In Nigeria, the origin of water shortage is dated as far back as the pre-colonial time when people had to journey from one part of the country to another in search of water.

The mismatch between demand for freshwater and its availability is a major causative factor of water scarcity although it may still arise from differences in human relationship (a social construct that culminates from product of affluence, presupposition and accordance with accepted societal standards, rules or expectations) or the resultant effect of modified supply patterns, rising from climate change. Water scarcity mostly affect people in the ghetto of developing countries as they are reported to, often, pay 5–10 times more per unit of water than people, in the urban areas, with access to pipe-borne water. This is because water scarcity is a relative concept and can occur at any level of supply or demand [49].

The availability of freshwater controls the bulk portion of the world economy. Technological advancement and industrialization are two other strong elements that threaten freshwater resources all over the world. In order to create balance, adequate provision of water is essential for agricultural purposes, drinking and cooking, industrial productions as well as recreation. Unfortunately, natural or artificial contaminants deny us of the right thus exposing us to a lot more challenging world. It is a well known fact that fresh water is an important necessity for our health [35, 50].

#### **3.4 Accessibility & affordability**

It is estimated safe drinking water is accessible by 89% of world population, while 11% do not have access to water suitable for drinking and cooking. Report from the "United Nation Development Programme", states that one out of six people do not have access to clean water, and this constitute about 1.1 billion people with lack or poor access to safe drinking water. On a normal basis, access to safe water in satisfactory amounts for drinking and domestic uses coupled with sanitation equipments that do not trade-off health or dignity is a need for every individual. The United Nations and other developed countries states that access to potable drinking water is an elementary human right, and it is a necessary step towards upgrading living standards globally. Unequal in access to potable water and hygiene are not morally acceptable, and are forbidden under international law. In some developing countries nearly 50% of the population do not have access to safe drinking water and hence, is characterize with poor health standard, especially in Africa, Middle East, Latin America and Asia. It is interesting to know that the number of people without access to safe drinking water is more than the number reported by the "United Nation Development

Programme". This is because there is little or no commitment in ensuring that most of the water supply facilities initiated during the MDGs in developing countries are functioning properly [9].

Equal access to safe drinking water according to the United Nation (UN) and other countries is a fundamental human right, and a key step towards enhancing living standards. Access to potable remains one of the main goal of Unite Nations-Millennium Development Goals (UN-MDGs) and also a major goal of the Sustainable Development Goals (SDGs). The importance of equal access to safe drinking water is further driven by goal 6 of The UN-SDG which states that *"Water sustains life, but safe clean drinking water defines civilization"*. But in spite of these pertinent claims, unequal access to safe drinking water is still a major challenge in the world particularly in developing countries. The only way to curtail this problem is to tentatively address the issue of poor access to water and poor water resource management since equal access to potable drinking water is also considered to be a human right, not a privilege, for every man, woman and child. Inadequate water productivity in the agricultural sector can negatively affect water quality [31].

Unequal access to potable water has been a rising issue that confronts a large portion of the world's population both in developed and developing nations. Several factors could be responsible for that ranging from proximity to available freshwater pool, political, cultural or economic factor. This plays out in the variation of access to safe water both among and within countries. In Congo 77% of the population dwelling in towns and cities can access potable drinking water but on the contrary, only 17% of rural dwellers have access to safe drinking water. But in the Lao Peoples' Democratic Republic, the reversed is the case because almost every people in the rural area of Lao has access to potable drinking water compared to the only 60% of the overall residents that dwell in the capital city of Vientiane. Most importantly is the variation in the use of freshwater resources from one country to another.

In developing countries, almost 90% of freshwater is solely used for agricultural practices, 8% for industrial actions, while only 5% of their available freshwater are used for domestic purposes. But in developed countries, industrial use of freshwater is about 59%, 30% for agriculture and just 11% for domestic uses [29]. From the public health viewpoint, the amount of the population with equal access to safe drinkingwater is the most vital single indicator of the overall success of a drinking-water supply scheme. There are various definitions to access to freshwater or supply coverage, with many of the definitions placing emphasis on safety or adequacy. The most accepted definition is that used by "reasonable access" to improved sources as being "availability of a minimum of 5.28 gallons per person per day within one kilometer of the user's dwelling from an improved source" [28].

The affordability of water has an important influence on the utilization of water and choice of water sources. Households with rock bottom levels of access to potable water system often pay a lot for their water than do households connected to a piped water system. The high price of water may push these households with least access to potable water to use to use different sources of water of water of poorer quality that represent a higher risk to health. Furthermore, high prices of water might scale back the volumes of water utilized by households that successively might influence sanitation and increase risks of disease transmission. When appraising affordability of potable water, it is pertinent to assemble data on the price at the point of purchase. However, if households are connected to the drinking-water supplier, this may be the tariff applied. But where water is bought from public standpipes or from neighbors, the cost at the point of purchase may be totally different from the supplier tariff.

Many different potable water sources (notably vendors) also involve costs, and these costs should be part of appraisals for affordability. In addition to periodic costs, the costs for elementary purchase of a connection should also be put in place when assessing affordability [28].

## **3.5 Sustainability**

Developing countries face a huge challenge with sustainable safe water supply. While facing the challenges of the "old" agenda which are providing safe water services to every household encompassing coverage changed, rising cost of raw water, inefficient water utilities, poor public spending, inefficient private financing in the informal sector, excessive cost and economic impact on end users, lack of innovative and equitable, approaches to financing of water and sanitation services, equal access to both the poor and the rich, development of efficient formal institutions and adequate private sector investment in the water sector, developing countries are now facing the challenges of the new agenda.

The most eminent challenge faced by low-income and middle income countries are that of new agenda - developing quality ambient aquatic environment. While the quality of the aquatic environment is a primary concern in every country, the condition among cities in developing countries is exceptionally critical. In some middleincome countries wastewater is seldom treated. For instance in most Middle-income countries of Latin America, only about 2% of wastewater are treated. Data from the United Nations Environment Program revealed that water quality is extremely poor in developing countries compared to industrialized countries. Moreover, while the quality of aquatic environment in high-income countries improved over the 1980s; middle-income countries did not experience any improvement, whereas low-income countries experienced a sharp decline [51]. Other major challenges facing sustainable safe water supply include lack of sufficient capital investment and good governance, lack of appropriate policies and programs that consider rural diversity, infrequent and insufficient application of adaptive capacity indicators in urban sustainable water supply, unavailability of sustainable and resilient smart water grids in urban areas, lack of adequate water demand and supply modeling.

#### **3.6 Climate change**

Most developing countries are located in the world regions that are exposed the severe droughts and seasonal changes in precipitation and evaporation and this create instability and challenges the source of the water at different times of the year. Climate change and water scarcity are increasing challenge posing serious global concern because of they create a corkscrew debt burden on developing countries. Climate change affects the rate of extreme weather events and thus increasing the unpredictability about freshwater availability and reliability. The rise in global mean temperature will cause a widespread, high-speed, and intensifying climate change which will in turn play a significant role in changing the quality of drinking water (see **Figure 2**). In order to curb this impending catastrophe, professionals need to explore and adopt the method of better and efficient interrelated mechanisms between climate change and drinking water quality. This can also be achieved by adapting and optimizing the already existing water management practices in ensuring drinking water safety.

More emphasis should be given to pressing climatic issues such as adequate water governance for cross-border basins, trans-boundary information systems, a well

*Safe Drinking Water: The Need and Challenges in Developing Countries DOI: http://dx.doi.org/10.5772/intechopen.108497*

**Figure 2.**

*Effect of climate change on drinking water safety [52].*

established knowledge base schemes for mountain and valley terrains and sharing benefit between upstream and downstream communities. Floods has the capacity to create more siltation-like problems (eutrophication, sedimentation, land-sliding, acidification and salinization) in river systems as well as the pollution of rivers and large dams which will cause source receptor problems. Stratification issues in lake abstraction areas and ventilation of abstraction point to break down the water-table layers are needed but these processes requires much energy and resources [9, 31, 52].

Developing countries are vulnerable to end-to-end of normal climatic variations. It is advisable to pre-empty the impact of rise in the global mean temperature, accumulation of green house gases in the atmosphere and continuous depletion of the ozone layers because climate change it will probably increase the frequency and magnitude of some extreme weather conditions and disasters. Whether the world will quickly adapt to climate change is subject to current adaptive measures and the development of workable models that are currently been pursued by developing countries. Many frameworks are presently available for vulnerability and adaptation evaluation with both merits and demerits. But one major loophole in the approach adopted by the developing countries is that of investing resource that focuses on recovery from a disaster than on the creation of future adaptive capacity. There is need to urgently increase the capacity to manage harsh weather condition in order to reduce their weight on the economy, social and human damage and capital investments, thus shielding developing countries from frequent borrowing of money from the international lending agencies. Developing countries must also incorporate disaster management and adaptation as part of long-term sustainable development goals in combating extreme climate variation and water scarcity. On the other hands, international monetary agencies and financial donors must overhaul and repackage their agenda and investment policies in developing countries to basically focus on capacity development rather than tailoring their investment in recovery operations and infrastructural development [37].

## **4. Conclusion**

Making water safe and potable is a big challenge in developing countries. More than 5 million people die yearly from water associated disease. Developing countries simultaneously face enormous financial, technical and institutional challenges in managing the quantity and quality of their water resources in a sustainable way. The high price of water may push these households with least access to potable water to use to use different sources of water of water of poorer quality that represent a higher risk to health. From the public health viewpoint, the amount of the population with equal access to safe drinking-water is the most vital single indicator of the overall success of a drinking-water supply scheme. Inadequate water productivity in the agricultural sector can negatively affect water quality. The problem of potable water shortage has become a source of concern in the world; locally and globally. Thus to maintain a robust and healthy society, adequate, reliable, clean, accessible, acceptable and potable drinking water supply has to be available for everybody. By giving priority to an enhancing and well planned, structured and governed and regularly supervised infrastructure coupled with related institutional capacities the challenge of seasonal climatic alterations can be well curtailed.

## **Acknowledgements**

We are grateful to God for making this project a success. Our heartfelt appreciation goes to my research team at Department of Microbiology, Evangel University Akaeze, Ebonyi State, Nigeria or their support and encouragement during the time of this work. We also acknowledge the team leader of this project Tea Jurcic and the entire team at IntechOpen for their support and encouragement throughout this work. Thank you all.

## **Author details**

Collins Onyebuchi Okafor1 \*, Ude Ibiam Ude2 , Felicia Ngozi Okoh1 and Blessing Osose Eromonsele1

1 Department of Microbiology, Evangel University Akaeze, Ebonyi State, Nigeria

2 Department of Applied Microbiology, Ebonyi State University, Abakaliki, Nigeria

\*Address all correspondence to<EMAIL_ADDRESS><EMAIL_ADDRESS>
© 2022 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

*Safe Drinking Water: The Need and Challenges in Developing Countries DOI: http://dx.doi.org/10.5772/intechopen.108497*

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## **Chapter 10**


*Editorial* **Quantum Transport in Mesoscopic Systems**

### **David Sánchez 1,\* and Michael Moskalets 2,\***

Received: 20 August 2020; Accepted: 26 August 2020; Published: 1 September 2020

**Keywords:** quantum transport; mesoscopic systems; nanophysics; quantum thermodynamics; quantum noise; quantum pumping; Kondo effect; thermoelectrics; heat transport

Mesoscopic physics has become a mature field. Its theoretical foundations and main models were established in the last two decades of the past century [1,2]. Ever since, quantum transport techniques have served as an excellent tool to understand the intriguing properties of charge carriers in nanoscale conductors [3,4]. However, in the last few years, the number of applications has grown so quickly that even experts find it difficult to stay updated with the recent advancements. The goal of the present special issue is to give a current snapshot of the field by means of a collection of review papers and research works that discuss the hottest theoretical questions and experimental results.

While the average current was the focus of early studies, the interest has gradually shifted to time-resolved transport. The motivation is partly due to new devices, such as single-electron emitters, which are able to inject quantized current pulses onto a Fermi sea for the investigation of inelastic and interaction effects upon electronic collisions. This is the subject of the review paper by Filippone et al. [5], in which Fermi liquid theories are employed to analyze strong correlations (Coulomb interactions) in the out-of-equilibrium dynamics of mesoscopic capacitors, a type of mesoscopic system whose response is purely dynamical. Here, dynamics is enforced via a time-dependent potential applied to a nearby gate. Under certain circumstances, the interplay of this potential and Coulomb interactions can lead to fractionalization effects in a single-electron transfer (quantized pumping). Chen and Zhu [6] find quantum pumping for a double-barrier system in the adiabatic limit. The novelty lies in their consideration of Dirac–Weyl quasiparticles. Tokura [7] also consider slow potentials, but the system is now an interferometer that allows not only for Aharanov–Bohm phases but also for spin-dependent shifts, due to both Rashba and Dresselhaus spin-orbit couplings. Meanwhile, Hashimoto and Uchiyama [8] tackle the nonadiabatic regime and present a complete analysis of the pumped charge, spin, and energy induced by temperature modulations in the attached reservoirs. A particularly useful approach that deals with this kind of problems is based on generalized master rate equations. Moldoveanu, Manolescu, and Gumundsson [9] illustrate the power of this method for a hybrid quantum-dot system that hosts both electronic and bosonic degrees of freedom. Among other things, they solve the master equations, including many-body effects in the transient response to time-dependent signals applied at the contact regions. Dynamically driven quantum devices are also suitable systems for testing alternative theoretical formulations. An example is the work of Pandey et al. [10], in which the Bohmian quantum theory is utilized to elucidate the role of non-Markovian conditions in graphene probed at very high frequencies.

In the recent cross-fertilization between thermodynamics and quantum physics, mesoscopic systems play a pivotal contribution. In their review article, Ansari, van Steensel, and Nazarov [11] connect information-theoretic concepts with the evaluation of entropy in quantum systems. They illustrate their discussion by calculating the entropy of various quantum heat engines. Quantum point contacts

are prototypical mesoscopic devices that can precisely work as heat engines. It is, therefore, of utmost importance to understand their maximum generated power, as discussed by Kheradsoud et al. [12]. Interestingly, they find that power, efficiency, and fluctuations are bounded by thermodynamic uncertainty relations. Additionally, Bustos, Mar ún, and Calvo [13] introduce mechanical degrees of freedom to analyze the dynamics of quantum motors built, e.g., from double quantum dots coupled to rotors. A Langevin approach allows them to generically describe both motors and pumps out of equilibrium, which are relevant for quantum refrigeration setups. Remarkably, some of the well-established results in linear response (Onsager reciprocity, fluctuation-dissipation relations) also hold far from equilibrium. Maisel and López [14] demonstrate, with a capacitively coupled doubled quantum dot system, that it is possible to find bias configurations that lead to stalling currents, around which the above results were verified.

Quantum conductors constitute excellent platforms for the measurement and manipulation of thermal gradients and currents while keeping the quantum character of energy carriers. Biele and D'Agosta [15] review the standard theoretical approaches to quantum thermal transport (Landauer–Büttiker formalism and Boltzmann equation), pointing to their strengths and limitations. To overcome the latter, they discuss advanced methods, such as time-dependent density functional theory, the nonequilibrium Green's functions approach, and density-matrix formulations. Atomistic computations are reviewed by Medrano Sandonas et al. [16] in the context of nanophononics. Clearly, phonons should be taken into account in any general description of heat transport in nanodevices, especially in molecular junctions. A density-functional tight-binding module specifically designed to deal with phonon transport is able to compute the phonon conductivity of molecules sandwiched between thermally biased metallic contacts. Perroni and Cataudella [17] consider the case of a fullerene and study the combined influence of vibrations and Coulomb interactions in the thermoelectric transport through the molecule.

In confined mesoscopic systems, electron–electron interactions can lead to strong correlations visible in transport measurements. A celebrated phenomenon is the Kondo e ffect, where the unpaired spin of an electron localized inside a quantum dot forms, at a low temperature, a many-body singlet with the spin density arising from conduction electrons that propagate in the leads attached to the dot. Tettamanzi [18] review the Kondo and the Kondo–Fano e ffects in silicon nanostructures, taking into account correlations between pseudospins belonging to di fferent degeneracy points in the conduction bands. Simultaneous fluctuations in both the spin and pseudospin degrees of freedom give rise to higher symmetry Kondo states. Lee, Dong, and Lei [19] propose a multiterminal setup comprising a quantum dot attached to two ferromagnetic contacts and one superconducting lead, with the aim of assessing both local and nonlocal conductances within a slave-boson mean-field approximation. Their main finding is a competition between the superconductivity proximity e ffect, Kondo correlations, and spin polarizations that could be analyzed with a careful study of the conductance.

We began this Editorial with an emphasis on time-dependent currents. We would like to finish our presentation with a somewhat related quantity, namely, the noise, since current fluctuations are defined from time correlators. Bulka and Luczak [20] analyze the electric current noise in a ring structure that supports persistent currents. When the ring is pierced by an external magnetic field, the interference pattern is a ffected by the Aharonov–Bohm e ffect and this is reflected in the noise as a function of the flux. In mesoscopic conductors, not only charge, but also heat fluctuations, are significant. This leads to heat and mixed charge-heat correlators, as illustrated by Ronetti et al. [21] for a harmonically driven quantum Hall bar. The system shows quasiparticle excitations of fractional charge (Laughlin states), and it is demonstrated that the mixed noise di ffers for integer and fractional filling factors. Finally, current–current correlations can provide us with valuable information about the electronic traversal time through mesoscopic constrictions. Ridley, Sentef, and Tuovinen [22] calculate the cross-correlations of graphene nanoribbons and find that the sample disorder increased the traversal time.

*Entropy* **2020**, *22*, 977

Overall, these papers represent an outstanding perspective of current research in nanophysics. They show that the field is actively developing and alive with problems that are interesting to a great variety of physicists, whose concerns range from condensed matter to quantum information and thermodynamics. There is still plenty of room at the bottom, which implies fruitful opportunities in the near future.

**Funding:** This work was funded by AEI grant numbers MAT2017-82639 and MDM2017-0711.

**Acknowledgments:** We express our thanks to the authors of the above contributions and to the journal Entropy and MDPI for their support during the preparation of the special issue.

**Conflicts of Interest:** The authors declare no conflict of interest.


**4. New antibiotics synthetic molecules**

In the race for the discovery of antibiotics some molecules paid a high price since they never reached the consumer, others on the contrary were the panacea to fight hundreds of pathogens [30]. However, the development of resistance from pathogens to antibiotics and their irresponsible use have led to the discouragement of production by pharmaceutical companies [31], while bioaccumulation and biodegradation are the new challenges added to new antibiotics [32]. In addition to fighting the same pathogens, new antibiotics shall aim to preserve soil and water quality and will prevent their accumulation and bioaccumulation. It is likely that the same active principle is used [33], perhaps better than synthesizing new molecules that are more complex to degrade. Anyway, new antibiotics must also fight against the same pathogens; nonetheless, they must also preserve soil and water quality, avoiding its accumulation and bioaccumulation, and perhaps that will be the hardest task, but it is worth it. "Even with more appropriate prescribing, it seems likely that

**169**

*Pharmaceutical Antibiotics at a Significant Level in Nature: From Hospitals, Livestock…*

antibacterial resistance will continue to accumulate in many pathogens and settings,

As emphasized in **Figure 1**, some hospitals around the world have their wastewater treatment plant (WWTP). However, the vast majority in the world in both developed [35] and developing countries [36] or in poor countries [37], hospitals water goes directly into the sewers, which in many cases reach the rivers and the sea carrying a huge load of antibiotics. Even, the larger hospitals in many towns dumped antibiotics are into the sewers. Recently, Bansal [38] published an excellent review about hospital effluents, proposing finally bioremediation for control and lowing the multidrug-resistant bacteria, and author concludes with the sentence: "Antibiotic compounds have a suspicious reputation among the class of pollutants referred to as 'emerging contaminants' as the biological activity of antibiotics is an intrinsic characteristic of their functional design". Then actually, there are two concerns: first the resistant bacteria [39] and second the antibiotic pollutant. Consequently, both problems would be repaired by not throwing more antibiotics

The Antibiotics' ecotoxicological risks over the effluent discharge on the aquatic

Hocquet et al. [40] say that in France and worldwide a few countries demand or recommend previous treatment of hospital effluents before discharge into the main wastewater stream for treatment at municipal WWTP. There are well-known cases such as those of the city of Montreal related at the St. Lawrence River [41]. In Norway Langford & Thomas [42] study by LCMS two antibiotics (clotrimazole and other not specified) among 38 pharmaceutical compounds, showing that perhaps the use of antibiotics in that country has already begun to be discouraged or used with responsibly in hospitals, not being the case for most of the remaining compounds. Santos et al. [43] made a biggest elaborated work where they found in WWTP 4 antibiotics as follow: fluoroquinolone, macrolide, sulfamethoxazole, trimethoprim calculated by mg per day per 1000 inhabitant were ranged between 19 and 1337,24–53, 75–199, and n.d.–43 respectively. The total antibiotics calculated by mg per day per 1000 inhabitant was ranged between 174 and 1612 and other

ecosystem is the main concern. Aydin et al. [36] found azithromycin, clarithromycin, and ciprofloxacin as most abundant in WWTP with seasonal differences ranged from 21.2 ± 0.13 to 4886 ± 3.80 ng/L in summer and from 497 ± 3.66 to 322,735 ± 4.58 ng/L in winter analyzing WWTP from some hospitals in Turkey. The total antibiotic load to the influent in those WWTP was 3.46 g/day in summer and

*DOI: http://dx.doi.org/10.5772/intechopen.95368*

**5. Antibiotics in wastewater from hospital**

especially in hospitals" [34].

into the environment.

303.2 g/day in winter.

antibiotics were ranged between 2 and 67.

**6. Antibiotics in drinking water, farm water, and aquifers**

Perhaps one of the most worrisome issues with non-treatment of hospital water is that water with antibiotics can reach farms and/or water for human or animal consumption and even plant irrigation. In Kumasi, a big city in Ghana, the hospital wastewater and effluents from waste stabilization ponds, are directly discharged as low-quality water into nearby streams which are eventually used to irrigate vegetables. The presence of 12 commonly used antibiotics was detected: metronidazole, ciprofloxacin, erythromycin, trimethoprim, ampicillin, cefuroxime, sulfamethoxazole, amoxicillin, tetracycline, oxytetracycline, chlortetracycline,

antibacterial resistance will continue to accumulate in many pathogens and settings, especially in hospitals" [34].


**5. Conclusive remarks**

*Sustainability Assessment at the 21st Century*

tree covered (grove and vineyard) by about 74.5 × 103

**4.2 Vegetation cover changes in the Hula Valley**

dunams. A small quantity of water (14–17 × 106

of Kinneret Headwaters.

48 × 103

123 × 103

permission.

34 mcm; 106

increasing anyhow.

not devastated.

m3

Jordan watershed. Givati [1] approximated an increase of 40 mcm/y consumption

Water legislative consumption inspected by the "Water Authority" was significantly reduced from >100 to 68 mcm/y at present implementation. Confirmed information documented restriction from 200 to 68 mcm/y. Conclusively, climate change, precipitation decline, and restricted legislative allocation essentially make sense. The whole Hula Valley is under plant cover since the late 1950s of which

dunams are presently tree covered (groves). The Golan Heights area is

tree covered area of the Upper Jordan Watershed Upstream during 2017 is about

headwater sources (Hula Valley Western Canal) to irrigate crops on the Dalton Plateau (Western part of the Upper Galilee). Water consumption for irrigation in this part of Israel is fully monitored and absolutely restricted to legislated

Water supply for irrigation on the Golan Heights (part of the upper Jordan watershed) is precipitation-dependent. Thirty-two reservoirs (total capacity

Givati [1] documented the decline of 77 mcm/y of Dan and Banias river (major sources of River Jordan) discharges and an annual decrease of precipitations on the

A reasonable option for invisible water loss in the Hula Valley is the underground preferential pathways gravitating subterranean water migration. Gophen [3, 4] and Gophen et al. [2] suggested 38 mcm/y water loss during drought seasons in the Hula Valley. The Kinneret water balance management was optimized between the dependents of natural parameters (precipitations and river discharge) and human demands (agriculture and domestic). The lake water level resulted in the fluctuations caused by those fluctuating parameters. The national supply (direct pumping from the lake and northern consumption) continued until a severe long-term (5 years) drought led to insufficiency; then a desalinization solution was implemented. Throughout this long-term process, Galilee and the Golan were populated, followed by agricultural flourishing, and the lake was

Calculated drought level using the SPI (standard precipitation index) scale during 1930–2016 [1] indicated 13 and 17 years of severe drought during 1930–1970

The search for well-known cases of water level (WL) decline in lakes is common among limnologists and hydrologists. Deterioration of water quality quite often by water level decline is accompanied by other factors. However, shrinkage measure of the lake is closely related to the Bathymetric features of the lake. In shallow lakes with a flat bottom surface (such as the Aral Sea and Lake Chad), a minor decline of WL exposes a vast bottom area and extreme shrinkage while in deep lakes (steep bottom surface) the opposite occurs: exceptional WL decline exposes a smaller area of the bottom surface.  Therefore, maximum water reduction from the Kinneret budget is 34 mcm/y. The maximum reduction of water removal from the Kinneret budget attributed to the increase in vegetation cover is worth only to 20 cm of the lake water level. Maximum storage in the Golan reservoirs occurs when regional precipitation is surplus while all other resources are plentiful and Kinneret WL is

Golan Heights of 246 mm during 1970–2010 (Mean 6.2 mm/y).

and 1970–2016, respectively; it also indicates climate change.

) were constructed on the Golan Heights to store natural run-

dunams. Consequently, total

) is also conveyed from

m3

**142**

The impact of climate change in the Upper Jordan Watershed was precipitation and consequently river discharges and available water capacities since the mid-1980s decline [14–16]. Regional air temperature increase was accompanied by the elevation of Lake Kinneret water temperatures. The ET regime during 2005-2018 in the Hula Valley was approximately stable (± 10%). Air temperature increase did not caused significant fluctuations of the ET values due to the high density of vegetation cover which reduced soil surface warming. The changes of the ecological Lake Kinneret trait were mostly due to nutrient dynamics of limitation shift from Phosphorus to Nitrogen.