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The world population is expected to increases up to 8 billion by 2015. Most of the cities in the world are scattered around the fresh water resource. These cities and villages have their own interests and they constitute a power order. Therefore, we have been trying to harmonize these cities and villages in the usage of fresh water resource and the discharging of wastewater as well, by using an engineering means of water treatment. The water environments science and technology should recognize the limit of fresh water resource for the sustainable development of the society, because the water service industries are the essential infrastructure of the community. In order to implement an appropriate risk management it is necessary to identify the goal of environmental management considering the social, natural and economical conditions. The energy dependent science technology should be reconsidered to be less energy and more resource conservation engineering means. Water supply and sanitation technology is not the sanctuary for the society, therefore more comprehensive water management system should be developed by other sectors, such as food production industry, with concern.
Journal of Water and Environment Technology, Vol.2, No.1, 2004 - 9 - Risk Management of Water Environment in New Paradigm Yasumoto Magara Professor, Environmental Risk Engineering Laboratory, Department of Urban Environmental Engineering, Graduate School of Engineering, Hokkaido University. Kita-13, Nishi-8, Kita-ku, Sapporo 060-8628 Japan magara@eng.hokudai.ac.jp ABSTRACT The world population is expected to increases up to 8 billion by 2015. Most of the cities in the world are scattered around the fresh water resource. These cities and villages have their own interests and they constitute a power order. Therefore, we have been trying to harmonize these cities and villages in the usage of fresh water resource and the discharging of wastewater as well, by using an engineering means of water treatment. The water environments science and technology should recognize the limit of fresh water resource for the sustainable development of the society, because the water service industries are the essential infrastructure of the community. In order to implement an appropriate risk management it is necessary to identify the goal of environmental management considering the social, natural and economical conditions. The energy dependent science technology should be reconsidered to be less energy and more resource conservation engineering means. Water supply and sanitation technology is not the sanctuary for the society, therefore more comprehensive water management system should be developed by other sectors, such as food production industry, with concern. KEYWORDS Risk management, Fresh water resource, Cancer risk, Infection risk, Appropriate technology INTRODUCTION The world population has reached 6 billion in 2000. It is expected to increase up to 8 billion by 2015 as shown in Figure 1. Generally, people tend to try to improve their lives, however, with such a rapid population increase, how long the earth will be able to support the lives of the people. In addition, many industrialized countries now have problems such as rapidly aging society and the tendency to have fewer children. These countries also try to establish new socioeconomic structure, with service industry in its center. It is the issue whether the new socioeconomic structure can or cannot promise a sustainable development of global system. WHO defines the health in its charter Figure 1 Increase of world population 0 1 2 3 4 5 6 7 8 9 1975 2000 2015 year World population [billion] Journal of Water and Environment Technology, Vol.2, No.1, 2004 - 10 - as follows: "Health is a state of complete physical, mental and social well being and not merely the absence of disease or infirmity." Paying the attention only to biological aspects is not enough when thinking about people having their lives with dignity as human beings. Energy and metabolism, which are essential factors for existence, are fully dependent on water. In the new century, it is doubtful whether we can secure water, which is the minimum necessity. Water is used not only in food production, but also in the secondary industry, third industry and in information/communication industry. When we use water, we use its attribute; that is, we use the dissolving power, transportation power, and heat property. Therefore, what we have to recognize is that when we use water, its amount does not change, instead, it changes into wastewater with different kind of attributes. The water environment is one aspect of water circulation on the earth. Especially fresh water resource, which is essential to our lives, has a constant amount of circulation: 150 × 10 12 m 3 , which circulates with a period of one week to 10 days, as shown in Table 1. Six billion people are now using 150 × 10 12 m 3 of this fresh water, and 8 billion people will use it before long and 10 billion people will use it in the middle of the 21st century. Table 1. Distribution of available fresh water resources River water River water (km 3 year -1 ) 100m 3 per capita per year Europe 2 900 4.2 North America 7 770 17 Africa 4 040 5.7 Asia 13 508 4 South America 12 030 38 Australia & Oceania 2 400 84 Globe 42 650 7.6 The fresh water evaporates from the surface of the earth and returns to the surface again as a rain. Originally rainwater itself does not contain any contaminants, however, in the process of precipitation, flowing, it takes some contaminants on because of the attribute of water. River water cannot be used for drinking purpose without any treatment. On the other hand, ground water can be used without any treatment, as long as there are no hazardous inorganic substances in the soil and they don’t dissolve into the water. Except this clean ground water, most of the fresh water cannot be used without any treatment for drinking water supply. If it is used without any treatment, it will cause various kinds of adverse health effects, including infectious disease, and the troubles in using water. When we use water, we have to go to the place where there is water or we have to carry water to the place, which it is used or needed. And, the water has to be processed according to its purpose of usage. In sewage and industrial wastewater management system, we also use the properties of water, because we remove unnecessary wastes from living environment or production site to provide water environment for the necessary condition. Most of the cities or villages in the world are scattered around the fresh water resource. These cities and villages have their own interests and they constitute a power order. Therefore, we have been trying to harmonize these cities and villages in the usage of fresh water resource and the discharging of wastewater as well, by using an engineering means of water treatment. It means that we have established an artificial water circulation system of using and discharging water within the huge Journal of Water and Environment Technology, Vol.2, No.1, 2004 - 11 - Figure 2 Natural and man-made water cycle natural water circulation, as shown in Figure 2. SOURCE OF RISK Impurities which exist in water include not only essential substances necessary for supporting the life of living creatures, such as nitrogen, phosphorus and iron, but also hazardous substances, such as arsenic and mercury, which are not just unnecessary for living creatures, but cause health problems. Furthermore, in water, parasites and infectious microorganisms, and chemical substances, such as agricultural chemicals, which may cause health problems to humans or living creatures, are included. In addition, some substances, which do not cause any hazard to humans or living creatures, but disturbs proper use of water, such as silt and sand making water turbid, are also included. Impurities in water can be classified according to the effects and sources, as shown in Figure 3. The discharge of pollutants to the water environment is overwhelmingly caused by human activities. There are various kinds of sources of pollutants, and the ones whose sources can be identified are called point sources, whether or not the wastewater is processed. Among these point sources, wastewater from domestic home, sewage is the biggest load to the water environment especially in the densely populated areas like metropolitan areas. The wastewater from factories and offices is another main cause of water pollution as a point source. The wastewater from factories varies in characteristics, depending on the raw materials or production processes. In addition, the types and load amount of pollutants discharged into the water environment vary, depending on the type of process. Unlike point sources, the sources of pollutants discharged into the water environment, which cannot be identified, are called non-point sources. Non-point sources include fertilizers and agricultural chemicals used in agricultural activities, which are discharged into the water environment along Land Sludge Transportation Energy Land Rain Fresh Water Ocean Deposit Sludge Pollutants Energy Storage Treated Wastewater Water use (municipal& industrial) Output control Agricultural use Energy Sludge River & Lake Input control Journal of Water and Environment Technology, Vol.2, No.1, 2004 - 12 - Figure 3 Risks and their source in water environments with irrigation wastewater, and substances in the atmospheric fall-out and pile up on the soil surface and is discharged into the water environment along with rainwater. Salts in the irrigation water or soil solution cause the adverse effect of salinity on crop production. The indirect effect of sodium is more popular. Sodium competitively inhibits the absorption of essential cations by crops. The increase in the sodium concentration in the medium brings about a decrease in the potassium, calcium or magnesium concentration in crops, especially in the shoots. Pesticides are different from other chemicals because they are used in open areas and in a large quantity and used only in certain seasons and because pollution by the pesticides is liable to be local. Pesticides are sprayed in paddy fields or crop fields. In general, only a small part of the pesticides sprayed takes on farm products, however, most part falls on the surface of the earth of the fields. In addition, part of the pesticides scatters during the spray and is carried outside the fields. Part of the pesticides which have fallen on the soil or which have been directly injected into the soil evaporates and passes into the atmosphere. As a result, a certain amount of the pesticides is distributed in the atmosphere as gas or in such form attached to suspended particulate. Pesticides in the atmosphere are caught by the falling rain and pass into the soil and the water system. Not only falling rain but also photochemical reactions contribute much to the reduction in the amount of pesticides in the atmosphere. Photolysis of pesticides is essentially the same as the photochemical reaction in organic chemistry. For example, an organic phosphorus insecticide, parathion, is known to be photo-oxidated from thiono compound (P=S) to oxon derivative (P=0) by ultraviolet irradiation. Some of these photolytic products have stronger in persistency and toxicity than the original chemicals. It has become evident that soil particles containing pesticides flow into rivers from the soil surface with rainfall and increases the pesticide load. Pesticides not only effuse from the surface of the soil but also percolate downward through the soil and gradually effuse into the river. That is, part of pesticides percolate downward to the underground with the percolating water and go out of the rice paddy areas through the under drain. Although such pesticides as CNP and PCP have been regulated further application in agriculture by their strongest hazard to human being as well as ecological system in environment, the impurities of them are still major source of Dioxins in water environment, today. From these evidences it is necessary to pay the strongest attention for the behavior of pesticides in the environment. EPIDEM IC DI SEASE ACU TE POISON CH RO NIC P OI S ON TAST E,ODOR & CO LO R DAMAG E FACI LITIES PATHO GENI C B ACT ERIA CYANI DE ETC. HEAV Y METALS SYNTHETIC ORGANICS SYNTHETIC ORGANICS PRODU CED IN TREATMENT PHENOLS GEOSMIN & 2MIB Fe & MN SUSPENDED SO LID CO RR OS I VI TY HUMAN ACTIVITIES HUMAN ACTIVITIES HUM AN ACTI VITIES HUMAN ACTIVITIES n utr ie nt s g eol og ical p ro per t ies HUMAN ACTIVITIES HUMAN ACTIVITIES geological properties Journal of Water and Environment Technology, Vol.2, No.1, 2004 - 13 - TASKS OF RISK MANAGEMENT The goal of the environmental risk management should be developed with scientific evidence of that has not arise any adverse effect to ecological system of livings, including human beings and their water usage. Needless to say, the goal of the environmental protection depends on the technological feasibility of the risk reduction, which influences the environment in whatever way, the feasibility of the applied treatment technologies, and the feasibility of the measurement. The aim of science and technology is to accurately establish the goals of the environmental management and to increase its feasibility. The science, which clarifies an environmental factor influenced on the health of human beings, started as epidemiology. In 1855, John Snow showed statistically that in the region where water service with sand filtration was used, the incidence of cholera was smaller than in other regions. Since then, the epidemiological method has developed with an aim to clarify the cases with a high incident rate, such as infectious diseases like cholera and occupational diseases, or the cases that which are easy to distinguish from other populations. Now, the epidemiological methods have developed to be more sophisticated with the advancement of information and computer science. The epidemiological method is very useful tool to set the goal of environmental management for protecting public health from environmental organisms, chemical and physical factors. This corresponds to UNEP/WHO Environmental Health Criteria. When WHO intend to set its drinking water quality guideline, it puts an emphasis on the results of clinical studies or epidemiological studies, which were found on human beings. However, we don’t have all the epidemiological data of all the contaminants in the environment, it has a limit when trying to examine newly generating synthetic and/or unintentional producing chemicals. When there is not enough data on human beings, the results of animal testing are used. Among the animal testing results, only the ones with mammal are useful, since the more accurate application to human beings is possible. It is necessary to adopt a method by which we can apply the results of animal testing as accurately as possible on human beings, while recognizing the scientific limitation. To put in another way, we should reduce as many uncertainty factors as possible in application of the animal testing results to human beings. The tolerable daily amount of exposure, as the goal of environmental management, is derived so as not to cause any health problems with applying uncertainty factor (not safe factor) for intra, inter species variances, accuracy of toxicological data and severity of the effect. And its value of the gene toxic carcinogens is derived so as to be the lifetime cancer risk should be around 10 -5 as at the virtually safe level. Since our society exists in the natural/man made water metabolic system, we are also affected by infectious microorganisms, which are co-existent with human beings and animals. The emergent and re-emergent infectious diseases, such as caused by E-coli.O-157, cryptosporidium, giardia, have been recognized in many countries, because of a significant international human migration or food distribution. As an example of this, as shown in Figure 4 water born cryptospordiosis occurred in Ogose, Saitama, Japan. Infectious microorganisms in water are scattered in the water, unlike chemical substances. Therefore as long as they are not taken into human bodies, they are not hazardous. In addition, many of infectious microorganisms have different levels of infection according to their life cycle. Therefore, the risk that infectious microorganisms have an effect on human health is quite probabilistic. The influence by infectious microorganisms is generally curable, not incurable like cancer, because of the development of medical treatment. Now, the risk of infectious diseases is treated as a yearly incidence. Since some infectious diseases are caused by food, it will be appropriate to accept 10 -4 a year of incidence caused by water. It means that the same waterborne infectious diseases may be commonly occurred in big cities, they can be ignored because of Journal of Water and Environment Technology, Vol.2, No.1, 2004 - 14 - Case of Cryptospordiosis ( Case/day) 0 200 400 600 800 17 May 15 June 1 July 1 June Date confusion with food borne disease Figure 4 Out break of Cryptospordiosis in Ogose, Japan or its quite low incidence itself. As a result, such incident rate of waterborne infectious diseases would be accepted socially. TASKS IN RISK MANAGEMENT ENGINEERING The background of the water treatment technology today lays the epidemiological study done by Dr. John Snow. The water treatment technology has been developed to simulate the groundwater cultivation process from surface water and self-purification action in surface water environments. The aims of this technology are to stabilize organic substances, to remove suspended particles and to inactivate infectious microorganisms, under a saturation limit of dissolved oxygen in the natural water environment. However, traditional/conventional water treatment technology, such as slow sand filtration, trickling filter, anaerobic digestion, requires a huge space, and now cannot secure enough space in order to meet ever-increasing water demand. Therefore, modern technology has changed into more space saving and energy-consuming technology, such as the coagulation sedimentation rapid sand filtration, and the activated sludge process. After energy, especially electric energy has become easily available, mechanical air blower has resolved the saturation limit of dissolved oxygen, and also another limit condition of filtration velocity in the natural environment has been resolved by making use of aluminum and chlorine produced by electrochemical process. The trade-off of time and space of nature to resources and (electric) energy has been established as shown in Figure 5. The energy-dependent science and technology has brought a convenient life for human beings and a new culture, including information. It also has made available chemical substances, which are not exist in the natural environment and inorganic substances, which were rare and scattered in the natural environment by condensing them. However, a part of such substances are discharged into living environment as waste, and even inorganic substances are discharged with higher concentration than natural condition. In order to manage such pollutants, the technology, which concentrates on natural purification process, is not enough, and another treatment technology, which can handle reverse-reactions when above-mentioned substances are produced, is needed. In addition, because the concentration of these substances is usually thinner than that in production process, the operation of concentration is Journal of Water and Environment Technology, Vol.2, No.1, 2004 - 15 - Figure 5 Risk management in drinking water services facility also necessary as a unit process. Absorption and exchange, including phase transfer, and oxidation-reduction of synthetic chemical substances, such as agricultural chemicals and heavy metals, become an appropriate unit operation, and technological development, such as activated carbon absorption, membrane separation, ozonation, and advanced oxidation process should be implemented intensively. However, most of these technologies are an energy consuming. From the global warming and global resource conservation points of view, it is necessary to develop a technology, which does not use so much energy. Therefore a water treatment technology, which does not use many resources and meet a zero-emission principle, is needed. It should be the energy-efficient/energy-saving technology, which may consume energy in material and chemicals development for treatment system, but consumes less energy in total. TASKS FOR RISK MANAGEMENT Unlike the safe drinking water act in the United States of America or WHO drinking water quality guidelines, water works law in Japan does not only provide that the people should always get a safe drinking water. This law is enacted in order to achieve people’s right and duty specified in Article 25 of the Constitution, to improve public health by supplying safe and acceptable water in every kind of water usages by a piped system. It can be said that its aim has been attained when seeing that water service is widely spread throughout the country. We now need another new norm on water service or drinking water based on a new concept. Water service is the only way to supply water necessary for life and social activities; therefore, what is needed for water service is to constantly supply water available for every kind of usage. Therefore, water service should be run by a regional monopolistic facility and all of its activities should be clear to all the service users. However, it is obvious that since water service exists in the natural water circulation, it should be based on the size of water circulation in that region. The country where water resource is limited; therefore, it should be controlled and utilized rationally by developing the institutes involved in all the sectors concern. It is true that water service is not the only one important service, but it is also true that water service plays an important role as social infrastructure. In order to secure this, metropolitan areas has secured technical, financial and human resources in order to make it function properly. Accordingly, C/DBAAA Environmental Standard Advanced Treatment Conventional Treatment Slow Sand Filtration Improving Quality Increasing Quantity Palatable and Virtually Safe Hygiene Raw Water Clean Quantity limited Large space & less energy Polluted Quantity not limited Less space & more energy Supplied Water Hazardous Clean & Safe 10 -6 10 -5 10 -4 Cancer Risk Journal of Water and Environment Technology, Vol.2, No.1, 2004 - 16 - the level of water service in metropolitan areas is very high in the global standard with regard to the amount, quality and charge. On the other hand, small scale water supply systems in rural area have difficulty in securing financial and technological resources, and they have to make efforts to function as social infrastructure, worrying about some risks of the disorder, such as the case of Ogose, of the system. Therefore the solidarity among all of water supply agencies should be encouraged to provide safe and palatable water not in the metropolitan area but also in the rural area. The source of burdens to water environment is not only caused by human activities, but also caused by harmful substances in soil in the process of water circulation, including groundwater and hot spring. Pollution caused by geological factors, such as arsenic, fluoride, boron, or antimony, inorganic hazardous substances occurs nationwide, and it prevents effective use of water resource. There have not been so many studies on such problems, because the system for groundwater use or for countermeasures against influential substances in the environment has not been enough. Since 30% of a man-made water circulation is shared by ground water, and it is an energy-saving water resource, the risk of the natural hazardous substances should be focused in the comprehensive water environment management. CONCLUSION Since the population and the industries have been concentrated in big cities, main focus has been put on pollution problems and wastewater control facilities. Therefore, the risk management of water environment based on sound water circulation has been mostly ignored. The science and technology for environment is not a mature science, as it is evident from the fact that it started only after water pollution and air pollution became serious in the rapid economic growth period in 1960's. From the viewpoint of water treatment technology, environment protection and quality evaluation, so many tasks and further advancement of technology are necessary. Japan’s environment protection system is at the same level of those of advanced countries such as Europe and the United States. This system has been established considering the nature, culture, science and technology and economic situation in Japan, although these factors were not assed enough. The criteria and guideline for international environment protection is being established. However, it is difficult to directly apply these criteria or guideline to developing countries or newly industrialized countries. It is necessary for us to coperate establish an appropriate standard or regulation for each country, considering the nature, culture, science and technology in each country. Water resource is limited, but world population is increasing each year. Advanced countries, including Japan, are dependent on developing countries for food and import water resource, which is unevenly scattered in the world, as a part of food. Thus advanced countries are deeply involved in global water circulation. Therefore, the solidarity among all countries and regions should be enhanced to develop appropriate risk management system in water environment so as to realize that “ the health for all with the sustainable development of the world”. . population 0 1 2 3 4 5 6 7 8 9 197 5 20 00 20 15 year World population [billion] Journal of Water and Environment Technology, Vol .2, No.1, 20 04 - 10 - as. Europe 2 90 0 4 .2 North America 7 770 17 Africa 4 040 5.7 Asia 13 508 4 South America 12 030 38 Australia & Oceania 2 400 84 Globe 42 650 7.6 The fresh