Environmental Degradation of Pasig River - Case Study Example

Sustainably Saving A River: The Pasig Rievr Story I. Introduction Environmental degradation is a problem faced by every nation in the world. Man'sunabashed exploitation of the environment and its resources has continually placed the globe's ecological well-being in a precarious position since the advent of the 20th century. The continuous and unchecked growth of populations has given additional pressures to these already dwindling resources. Limited resources are constantly in increasing demand as global populations get out of hand. Limited resources are further exploited by poor yet large populations for temporary economic gains. Economic competition on a global scale brought about by the movement towards globalization has also contributed immense pressures on the environment. This is also argued in the context that sustainable development among poor nations had been a difficult task, given the tendency of these countries to undertake exploitive economic activities (mostly through extractive industries such as mining, forestry and agriculture). The depletion of their natural resources have only given these underdeveloped countries temporary economic activities which would disappear as soon as their resources have been depleted. It is often perceived that free trade and globalization only benefits those whio have the financial leverage, and at the expense of those who do not. Among the Third World countries facing such problems in terms of environmental degradation and growing economic pressures in the face of an ever-increasing population is the Philippines. A prime example of the high price the country has to face in its struggle for economic survival is the plight of the Pasig river. II. Discussion A. Brief history of the Pasig River The Pasig River is the main river system in Metro Manila. Technically an estuary channel, its 25-kilometer stretch connects the large lake known as Laguna de Bay to Manila Bay. Laguna Lake is one of the largest freshwater lakes in the world had for centuries been a source of food, raw materials and the site of various economic activities. The flow of the river channel depends on various factors and the difference between the elevations of Laguna de Bay and Manila Bay. During the dry season when there is less volume of water in Laguna de Bay, the river channel tends to flow in the direction of Manila Bay towards the freshwater lake. In the wet season when water elevation in the lake is higher than that of Manila Bay, the natural channel flow is from the lake emptying into the sea. The river is an invaluable ecosystem linking the lake and the sea. It is among the Philippines' numerous irreplaceable natural resources. Fish have spawned and their fries and fingerlings have been nurtured by the mineral-rich contents of this estuarine channel. Settlements have long occupied portions of the Pasig River even before the Spaniards colonized the Philippines. It served as the main highway among settlements located along its banks and functioned as the umbilical cord to other settlements within the interior locations both near and distant from Laguna de Bay. Like many rivers all over the world, the Pasig River has suffered from abuse and neglect. The Pasig River and its tributaries have long been pressed into service and these have taken their toll on the river. The once pristine and sparkling waters which provided clean drinking water to the elegant Spanish villas lining its banks has now been transformed into a virtual waste basin for an economically struggling industrial center that serves as the heart of a nation. More than 300 factories and 10,000 households have replaced the dainty native huts and romantic Spanish villas of old. The sweet and quenching waters have become a reeking soup of industrial and domestic wastes. The once abundant fish and plant life have been replace by only the toughest of scavengers, both animal and human alike. It is estimated that 330 tons of domestic and industrial wastes are discharged into the river every day. This pollution has in turn reduced the biochemical oxygen available in the water to such low levels that it could no longer support any marine life. There have been several attempts to rehabilitate the Pasig River. Sadly, these all failed to take into account the larger context of the urban environment which has become an integral part of the Pasig River. Understanding Sustainability There are several social indicators of sustainability that are important in the rehabilitation of an ecological and natural resource like the Pasig River. The rehabilitation of the river must take into consideration the overall urban context of the riverine environment. For example, the presence and impact of human populations and their activities on the channel should be taken into consideration. However, the approach will not be simple considering the fact that population characteristics, their activities and impacts or effects on the river system would vary from one area to another. Thus, it is important that we choose the proper indicators that would give us a good reading and measure of our rehabilitation efforts. A. Indicators Measuring Equity 1. Poverty Indicators ''''''''''''' People and their quality of life are central issues in sustainability. Equity deals with the extent by which resources are distributed, opportunities are presented and decisions are made. It involves the provision of employment opportunities and access to social services. The relevance of equity encompasses communities and nations. Among the significant issues included in equity are poverty alleviation, employment, distribution of income, to name a few. The poor may feel powerless and insecure, facing chronic systemic problems such as unemployment, malnutrition, illiteracy, poor health, and civil insecurity. The concentration of the poor in areas may lead to over-exploitation and unsustainable practices. Determining Percent Population Below the Poverty Line is a good measure in terms of social, equity and poverty. This measure allows us to make poverty comparisons to assess the overall performance of a country in the alleviation of poverty. It also allows the evaluation of specific policies/projects pertaining to poverty alleviation. An example of a poverty comparison is the poverty profile wherein the aggregate poverty measure can be broken down into individual poverty measures intended for various subgroups within a population. These subgroups include gender, region of residence, employment sector, education level, or ethnic group. Good poverty profiles can reveal important information such as prioritisation in terms of public spending. When poverty comparisons are made over time, they allow for assessment of overall performance from the perspective of the poor (Ravallion 1994). Measuring poverty is an integral aspect of sustainable development since its alleviation had always been a major concern for policy decision makers. It is also significant because it provides a view point which integrates issues on development, use of resources, quality of the environment, and human welfare. In using Percent Population Living Below the Poverty Line, policy makers are able to measure the magnitude of poverty by measuring its proportion based on the population. It gives a picture of the extent of poverty, by determining through measures of living standard, what proportion in a population is below the poverty line. This measure will show that a greater proportion of the population will fall below the poverty line as this indicator also increases. This indicator is related to other sustainable development measures. Among the sustainable development measures this indicator is linked to are: Gross Domestic Product per capita (GDP), net migration rate and adult literacy rate. It is closely related to the Poverty Gap Index and the Squared Poverty Gap Index, which provides more details about the poverty situation. As the Percent Population Living Below the Poverty Line measures the magnitude of poverty in a population, the Poverty Gap Index measures the extent of poorness of the poor; while the Squared Poverty Gap Index shows how severe poverty is by giving emphasis on the poorest among the poor (Shaohua 1998). There is no universally accepted measure for poverty, and the Percent Population Below the Poverty Line merely guides us along key issues like the different approaches to individual welfare. It also requires comparisons over a period of time for a country, which allows practitioners and decision makers identify specific indicators that are suitable to their situation and approach. However, being specific with the national situation, government approach and choice of indicator compromises the ability to make comparisons on an international level. There are questions that must first be answered to compute poverty measures: i) How do we measure an individual's economic welfare', ii) At what level of measured welfare is a person considered poor. Data for the Percent Population Living Below the Poverty Line are those dealing with living standards. They are often acquired through household surveys. often National and international data can be available through government statistical agencies. These agencies provide published reports. Many developing countries have done household surveys on living standards which are representative of their national population. The Percent Population Below the Poverty Line has certain limitations. Developing countries have used consumption per person as a measure, which has an exaggerating effect on poverty in relation to large family sizes. The use of assessments of regional and sectoral poverty profiles would tend to be more accurate. Value judgment and arbitrariness cannot be avoided in using the Percent Population measure in the identification of the poverty line and in defining individual welfare. These definitions would affect the overall poverty comparisons. Problems also arise in the use of data from household surveys sourced from different countries. Definitions of poverty may differ from one country to another. The Poverty Gap Index and Squared Poverty Gap Index can fill in the gaps not covered by the Percent Population Below the Poverty Line measure. The Poverty Gap Index shows how poor are the poor. It measures the degrees by which individuals on average fall below the poverty line. These are expressed in percentages and their aggregate constitutes all those that fall below the poverty line. (All 2005). The Gini Index of Income Inequality measures the extent by which a population distributes a resource unequally. The measure is scaled from zero to one, with zero indicating no inequality and one indicating the maximum possible inequality. As an example using the lowest 20% of a population ranked according to per capita income, the question that would be asked is "What proportion of the total income is attributable to this 20% portion of the population'" If the proportion of the total income is also 20%, then there is fairness. If the proportion of total income is less than 20%, then there is inequality (Leslie ). The Gini Index provides a measure of inequality in resource distribution within a population. This measure is important in dealing with equity in relation to sustainable development. The poverty rate of a country or region is directly related to income or resource distribution. The per capita GDP can define the material welfare, but statistical averages can conceal the diversity that is present in a country. It therefore becomes important that income and wealth distribution within a population be looked into to reveal vital information and give a true picture of poverty conditions. A country's GDP may be high but the distribution of income and wealth is so unequal that the majority of the population are poor. The Gini Index is a reliable tool in measuring income inequality over a period of time and in making international comparisons (Chen et al 1992). B. Indicators Measuring Health 1. Health Care Delivery Indicator The Percentage of population with Access to Primary Health Care is a popular measure, which allows the monitoring of access by the population. Access to health care does not solely pertain to physical access, but also includes economic, social and cultural accessibility. However, this measure should also be complemented by actual coverage of services and quality of care. The premise is that the more accessible the health care system is, the greater propensity of the population to utilize it to improve their health. The Global Strategy for Health for All has outlined international targets in its Ninth General Programme of Work. Individual countries have also complemented this by establishing their own national targets. This measure is linked with other socio-economic indicators dealing with the percentage of people who have access to other components of primary heath care. In this measure, the proportion of people living within a convenient distance to primary health care facilities is derived from the total population. The weakness of this measure is that the physical proximity of health care facilities is used as a replacement for the availability of health care. The presence of facilities does not take into account the adequacy of equipment, quality of care, affordability, and cultural or social acceptability. Gaps using this measure should be covered by availability of services, quality of services, acceptability of services, affordability of services, or utilization of services. Data for this measure are not routinely available. However, national statistical offices and National health agencies can provide data in varying degrees of completeness (WHO 1981). C. Education Indicator Adult Literacy Rate determines the percentage of the population 15 years old or above that is literate. This measure helps determine the portion of the population which is capable of using the written word in everyday life and have the capability to continue learning. It is the cumulative accomplishment of education in spreading literacy, and gives decision makers the opportunity to plan programs to extend literacy to the remainder of the adult illiterate population. Literacy is important in the promotion and dissemination of sustainable development among the population. It is also important in enabling the population to address issues on sustainability and the environment. Most countries aim for full literacy or the total eradication of illiteracy. This measure is strongly linked to other basic needs such as education, capacity building, information and communication. It is also linked to school enrolment ratios and the population of those who reach grade 5 education in primary schools. All these contribute to a nation's stock of literate people. There are underlying concepts which are important in using this measure. A person is literate if he can, with understanding, read and write simple statements about his everyday life. He becomes functionally literate if can engage in activities which are necessary for the proper functioning of his group or community. He should also have the capability to continue using reading, writing and calculations for the continued development of his community. Those who do not fall under any of the two categories are considered illiterate. The limitation of this measure stems from literacy being a relative term. There are varying forms and degrees of literacy. An individual may have difficulty in textual comprehension but may be literate in numeric terms. Since each sphere in life entails different literacy skills, literacy can be defined in terms of school, work, home and society. One way of estimating literacy is in terms of educational attainment, assuming that people with no formal schooling are illiterate. However, actual tests should be implemented to determine literacy in reading, writing and numerical calculations. However, the undertaking of such tests are time consuming and expensive. Data for this measure are often collected during national censuses and household surveys as part of the demographics information. Most national data are out of date because of the long periods between censuses and the late release of census data. The data must also be complemented by data by gender, age group and area. The measurement of functional literacy would be a good alternative to the Adult Rate of Literacy measure. The United Nations Educational, Scientific and Cultural Organization (UNESCO) also undertakes periodic estimations to fill in data gaps (UNESCO 1995). D. Security Indicator The Number of Recorded Crimes per 100,000 Population is a popular measure of sustainability in terms of security. This measure is based on law enforcement statistics. The purpose of this measure is to record crimes and operations of criminal justice systems so that the analysis and dissemination on a global scale could be improved. Crime is a phenomenon closely associated with economic and social development and it can act as a barrier national development. It affects the material and spiritual well-being of individuals through the creation of a violent and fearful environment. It diminishes the quality of life because of the dangers it poses to humanity. It is imperative that governments should provide safe and peaceful lives to its citizenry so that they would have the liberty to pursue lives of better quality and prosperity (UNICRI 1995). This indicator is closely associated with poverty and inequalities in income and resource distribution. It is also related with overall economic performance such as the GDP and rapid population growth. This measure focuses on the number of offences covered under the penal code, but excludes road, traffic and petty offences. incidents, counting methods, and the accuracy and reliability of the recorded information (ICVS 1998). E. Population Indicator Measuring Population Growth Rate determines the average annual rate of change of a population. It shows the speed by which a population is growing. Long term sustainability is affected by population growth, and its relevance is associated with other sustainability factors. High population growth rates can strain the capacity of nations to address and provide solutions to a wide range of concerns. Population growth coupled with poverty may also lead to pressures upon the environment and the adoption of unsustainable patterns of production consumption. Population growth has impacts on other indicators. It affects the economic, educational, social, cultural, and environmental components of a nation, creating pressures that hamper if not derail sustainable development pathways (DESA 1999). The computation of rate of population growth can be expressed by the formula: r = 100 ln (P2 /P1)/(t2 -t1), where population growth ( r ) between two period (t1 and t2), is computed as exponential growth, with P1 and P2 being the respective populations during T1 and T2. The result or population growth rate is expressed in terms of percent per annum. The computation can be done using data from two censuses. It can also be derived using the number of births, deaths and migrants (DESA 1999). F. Environmental Measures 1. Agricultural Indicators The use of agricultural inputs such as fertilizers and pesticides has an effect on the ecological well-being of the Pasig River. The areas surrounding Laguna de Bay and those proximate to Metro Manila are primarily agricultural lands. Rain water can drain from the various farm areas can carry chemicals from fertilizers and pesticides. The runoff then drains into streams which connect to tributaries of the Pasig River. The Use of fertilizers is a valuable because it determines the extent by which they are used per given area of land. This measure shows the intensity that fertilizers are used in agricultural production. The primary goal of agriculture is to increase food production. This measure gives a picture of the pressures arising from increased agricultural activities. The extensive use of fertilizers can result in the eutrofication of bodies of water, increased acidity of the soil, and contamination of water supplies. The overall effects would be determined by practices to prevent or decrease pollution, types of soils, crops being planted, and weather and other meteorological factors. This measure is closely associated to other areas such as the use of pesticides, emission of greenhouse gases, biochemical demand, and the like. The data from the various types of fertilizers used are broken down into three main categories: nitrogen (N), phospohorous (P2O3) and potassium (K2O). Agricultural land refers to the totality of arable and permanent crop lands, and areas which are permanently used as meadows and pastures. Data can be gathered from industry and non-traditional sources. For developing countries, the total amount of fertilizer consumed (disappearance) is deducted from the total importation volume, and are then divided by the total agricultural land. One limitations of this measure is that it does not show the environmental impacts caused by volatilisation and leaching, which are influenced by the condition of the agro-ecosystem, farm management practices and cropping patterns. Another agricultural measure of sustainability is the Use of Pesticides. Like the measure in the use of fertilizer, pesticide measurement is based on the volume (in metric tons) of active ingredients applied for every unit of land. The use of pesticides to increase production has produced problems such as the persistence of chemicals in ecosystems. Aside from being persistent, pesticides are toxic and mobile, contaminating the soil, water and air. It has major impacts on both humans and wildlife, tending to increase in toxicity through the food chain. The use of pesticide is directly related to the intensity of agricultural activity. Same as in the use of fertilizer, pesticide use is measured by the volume utilized (domestic disappearance) of active ingredients. The information is derived from the total importation of pesticide by a country and by deducting the domestic disappearance of active ingredient, then dividing it by the total agricultural area. 2. Fisheries Indicators In Fisheries, measuring Annual Catch By Major Species is a popular indicator which shows the changes in biomass in relation to previous statistics. It serves to warn fisheries about the condition of their fishing grounds and their capacity to withstand pressures of intensified activities. This measure requires the taking into account of the high variability of some marine species. Since the seas are less accessible to humans and most marine species are highly mobile, it is difficult to get statistics about peak catches. Likewise, many marine populations are highly influenced by climatic and environmental conditions. Data for this type of measure can be derived from annual catches categorized by major species and Spawning Stock Biomass (SSB) if they are available. The FAO has available data on annual catch. SSB data are usually available through national fishery commissions (FAO 1995, Grainger & Garcia 1996, FAO 1999). 3. Forest Indicators In determining sustainability in forest lands, measure can be done by determining the Forest Area as a Percent of Land Area. This measure shows the amount of natural and plantation forest lands through a given period of time, giving a picture of how much forest cover remains and the rate by which it is being lost. Aside from providing valuable resources, forests provide invaluable ecosystems throughout the world. They prevent soil erosion, support biodiversity, serve as natural filtration systems for pollutants, reduce the effects of greenhouse gases, provide raw materials, conserve soil and water, among other uses. Alarming rates of deforestation are often closely linked with unsustainable practices not only in forestry, but also in the agricultural sector. Accurate data on a nation's forest area is imperative in the formulation of policies for the conservation and sustainable development of its forest resources. The measurement of forest cover is also linked closely with land use, changes in land conditions, the intensity and practices in forest production activities, conditions of wildlife, arable land, among others. The forest area is computed as the totality of all natural and plantation forests with a tree crown cover that is equal to tern percent. The rate of deforestation can be derived by the compounded annual rate from year P to year N. (FAO 1993, 1995 1999, Harcharik 1995). G. Water Quality Biochemical oxygen demand (BOD) is a measure of the amount of oxygen needed for the oxidation of organic material in water. It is measured in milligrams per litre (g/l) used up within a five day period at a constant temperature of 20 degrees Celsius. Water is important for sustainable development and its supply is vital to a wide range of uses from the domestic to the industrial. Strict standards have been adopted by countries to protect health and prevent the occurrence of other harmful effects of poor water quality. High BOD can mean that the water has high concentrations of faecal matter. It may also mean high concentrations of dissolved carbon from non-human and animal sources. Water contamination can restrict or limit its use and harm sustainable development. It would also increase cost in the production of safe drinking water and the addition of chemicals such as chlorine may result in the production of other substances that are toxic to humans. High BOD would also affect aquatic life, such as fish and other organisms and upset the ecological balance. It is therefore important to monitor pollutants and identify their sources. BOD is measured by filling an airtight bottle with water and allowing it to incubate for five days at 20 degrees Celsius. Dissolved oxygen is measured before and after incubation. The difference of the two readings is BOD5. This measure only provides empirical instead of absolute results. It allows researchers to compare samples but does not indicate the concentration of contaminants in the water. The BOD can also rise due to eutrophication, or the increase in nutrients such as nitrogen and phosphorous, such as those washed from fertilizers. Increased nutrients would bolster the growth of algae which would increase oxygen consumption. Chemical Oxygen Demand (COD) may be used as an alternative to BOD5 to determine the oxygen content of a water sample which is prone to oxidation by a chemical agent (American Public Health Association 1989, WHO 1993, ISO 646171). Rehabilitation Initiatives A comprehensive rehabilitation program was begun by the Philippine government in 1989 in cooperation with Denmark. The Pasig River Rehabilitation Program (PRRP) was designed to integrate various approaches with the aim of restoring the Pasig River and its tributaries back to health. The Depatment of the Environment and Natural Resources was tasked to be the lead agency with close cooperation from the Danish International Development Assistance (DANIDA). The PRRP also involved various national government agencies, local governments, non-government organizations, community groups, professional associations, and business groups.'The main objective of the PRRP was to improve the environmental condition of the river within 15 years. Its tasks focused on commercial, industrial, and household pollution; solid waste management; squatter resettlement; waterways dredging; hauling sunken barges; riverside development; and public awareness. The rehabilitation of the Pasig River eventually became among the priority programs of the Philippine government. Among its fundamental elements is sustainable development in the provision of a clean and healthy environment to its citizens. It was in January 6, 1999 that President Joseph Estrada signed Executive Order No. 54 creating the Pasig River Rehabilitation Commission (PRRC) to oversee the overall rehabilitation of the Pasig River. Among the major concerns of the PRRC are the regulation of solid and waste water disposal into the river and the resettlement of informal settlers (squatters) residing along the river banks. Another mandate of the PRRC is to build parks along the river banks which would serve as structural barriers against human and industrial encroachment. The PRRC adopted the goals of the PRRP and gave priority to the location of the more than 10,000 households living along the river's banks. They also prioritized the monitoring of industrial establishments, ensuring proper waste disposal. Legal measures were also adopted with Presidential Decrees No. 600 and No. 979, -known as the marine anti-pollution law which serve as the bases for the prosecution of polluters. The government through the DENR is tasked to implement these laws and apprehend violators and impose the corresponding penalties. The private sector became actively involved with the Sagip Pasig Movement and Piso Para Sa Pasig. These organizations were responsible for community organizing, promoting community-based waste management program, and launching beautification projects. Socio-economic acceptability became a backbone in the implementation of the various programs and projects in the rehabilitation of the Pasig River. Thus, public consultation became a primary feature in the planning and implementation of programs and projects. These requisites are further required by the DENR's Environmental Impact Assessment System. Other assistance such as a PhP 20 million grant from the Belgian government also gave impetus to the rehabilitation efforts. However, the estimated PhP 15 billion needed to rehabilitate the historical river may not be enough. Booming population growth places the number of riverside residents that need to be resettled at 40,000. III. Discussion The environmental degradation of the Pasig River was a the result of countless decades of abuse and neglect. Human impact on the river and its ecological system has contributed to its virtual "death". However, efforts of the Philippine government underline the importance of this water channel to the ecological well-being of Metro Manila and its it population. It is significant to note that the Philippine government and other local and international cooperating agencies and institutions have forwarded sustainability in development as a prerequisite in the rehabilitation of the Pasig River and its tributaries. As was correctly and astutely observed by experts, past failures in rehabilitation were borne out of the failure of proponents to take into consideration the total urban and economic context of the Pasig River and its ecosystem. It is therefore important that emphasis be given on the appropriate indicators of sustainability cited by this paper. Only with the comprehensive and integrated confrontation of these social, economic, cultural and health aspects which comprise the urban society known as Metro Manila can any rehabilitation effort be given a fair chance at success. References: American Public Health Association, American Water Works Association, and Water Pollution Control Federation. Standard Methods for the Examination of Water and Wastewater. 17th Edition, 1989.' All, J.H. (2005) Poverty Manual. http://siteresources.worldbank.org/PGLP/Resources/povertymanual_ch4.pdf#search='poverty%20gap%20index Chen, S., G. Datt, M. Ravallion. POVCAL: A Program for Calculating Poverty Measures from Grouped Data. Poverty and Human Resources Division, Policy Research Department, Washington DC: World Bank. 1992. Criminal Victimization in the Developing World, UNICRI, 1995. ' International Crime Victim Survey (ICVS): International Conference on Surveying Crime - A Global Perspective, Conference Report, UNICRI, 1998. ' International Organization for Standardization. Water Quality: Detection and Enumeration of the Spores of Sulphite-reducing Anaerobes (clostridia). Part 1: Method by Enrichment in a Liquid Medium. ISO 646171. FAO. 1993. Forest resources assessment 1990: Tropical countries. FAO Forestry Paper (FAO), no. 112 / FAO, Rome (Italy). Forestry Dept., 110 pp. ' FAO. 1995. Code of conduct for responsible fisheries. FAO, Rome, 41 pp.' FAO. 1995. Forest resources assessment 1990: global synthesis. FAO Forestry Paper (FAO), no. 124 / FAO, Rome (Italy). Forestry Dept., 100 pp. FA0. 1999. Indicators for sustainable development of marine capture fisheries. FAO Technical Guidelines for Responsible Fisheries, no. 8, 68 pp.' FAO. 1999. State of the World's Forests (FAO). / FAO, Rome (Italy). Forestry Dept., 154 pp. ' Grainger, R.J.R. & S.M. Garcia, 1996. Chronicles of marine fishery landings (1950-94): Trend analysis and fisheries potential. FAO Fish. Tech. Pap., no. 359, 51 pp.' Harcharik, D.A. 1995. Forest Resources Assessment 1990: non-tropical developing countries. / FAO, Rome (Italy). Forestry Dept., 12 pp. ' Population Division, DESA, World Population Prospects: The 1998 Revision. Vol. I. Comprehensive Tables (United Nations publication Sales No. E.99.XIII.9, New York, 1999).' Ravallion, M. Poverty Comparisons. Fundamentals in Pure and Applied Economics, Volume 56, Harwood Academic Press, Switzerland. 1994. Shaohua, C. and Ravallion, M. Global Poverty Measure 1987-98 and Projections for the Future. World Bank, Development Research Group, Washington, D. C. Forthcoming. Statistics Division/DESA, 1997 Demographic Yearbook, (United Nations Sales No. E/F.99.XIII.1, 1999). ' UNESCO Statistical Yearbook (annual editions); Compendium of Statistics on Illiteracy: 1995 Edition, UNESCO, Paris. 1995. ' WHO, Development of Indicators for Monitoring Progress towards Health for All by the Year 2000, Geneva, 1981. WHO. Guidelines for Drinking-Water Quality. Second Edition, Volume 1 Recommendations, WHO, Geneva, 1993, and Volume 3: Surveillance and Control of Comments Supplies, WHO, Geneva, 1996. ' Read More