Water and Soil Pollutants

With three-quarters of the earth s surface covered by water and much of the remainder covered by soil, it is not surprising that water and soil serve as the ultimate sinks for most anthropogenic chemicals. Until recently the primary concern with water pollution was that of health effects due to pathogens, and in fact this is still the case in most developing countries. In the United States and other developed countries, however, treatment methods have largely eliminated bacterial disease organisms from the water supply, and attention has been turned to chemical contaminants. 

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Menzer, R.E. and J.O. Nelson. 1986. Water and soil pollutants. Pages 825-853 in C.D. Klaassen, M.O. Amdur, and J. Doull (eds.). Casarett and Doull s Toxicology, Third Edition. Macmillan, New York. 

Consequently, primary prevention should be designed to reduce or eliminate absorption by inhalation or by topical contact. Atmospheric pollutants gain entry by inhalation and by dermal contact. Water and soil pollutants are absorbed through inhalation, ingestion, and dermal contact. 

Environmental beryllium exposure is not generally thought to be a hazard to human health except in the vicinity of industrial sites where air, water and soil pollution have occurred. 

A decade ago, only a few pollutants were monitored. However, current regulations impose the monitoring of an increased number of substances at increasingly lower detection levels. Special surveillance is conducted in establishments known to release pollutants into the environment. Similarly, hazardous chemicals such as pesticides and herbicides are constantly identified and quantified. Several of these are related to air, water and soil pollution. 

The responsibility of chemical process managers for preventing air, water, and soil pollution has indirectly influenced plant safety by requiring better control of plant processes to prevent releases of hazardous materials. Regulatory legislation was introduced by the Health, Education, and Welfare Department (Health and Human Services) and the U.S. Environmental Protection Agency (EPA) to require (/) improvements in air quality (1955 Air Pollution Act ... 

Pesticides are also a major source of concern as water and soil pollutants. Because of their stability and persistence, the most hazardous pesticides are the organochlorine compounds such as DDT, aldrin, dieldrin, and chlordane. Persistent pesticides can accumulate in food chains for example, shrimp and fish can concentrate some pesticides as much as 1000- to 10,000-fold. This bioaccumulation has been well documented with the pesticide DDT, which is now banned in many parts of the world. In contrast to the persistent insecticides, the organophosphorus (OP) pesticides, such as malathion, and the carbamates, such as carbaryl, are short-lived and generally persist for only a few weeks to a few months. Thus these compounds do not usually present as serious a problem as the earlier insecticides. Herbicides, because of the large quantity used, are also of concern as potential toxic pollutants. Pesticides are discussed in more detail in Chapter 5. 

When designating which ministry is to have primary responsibility for chemicals control, familiarity with legislation of relevance for the management of chemical risks is of importance. Therefore, countries often confer responsibility for chemicals legislation on ministries of the environment or ministries of health. Ministries of the environment (or the like) may be preferable due to the fact that issues of risk assessment and risk management in general, as well as for chemicals, are frequently dealt with in these ministries (air, water and soil pollution, waste problems). Furthermore, modem chemicals control at an international level, in addition to focusing on health problems, focuses very much on environmental risks and environmentally mediated health risks, such as problems with POPs. 

The gains for society of improved chemicals control may be substantial, though not easy to quantify in monetary terms. They include, for example, reduced costs for health care as a result of fewer accidents with chemicals, fewer acute health effects caused by poisonings, skin corrosion or bums, reduced risk for chronic effects such as allergies, cancer, etc. Furthermore, improved chemicals control will lead to a reduction of costs for remediation of environmental damage and of other costs following from emissions, e.g. water and soil pollution due to accidents or misuse of chemicals. 

Pollutants can enter through direct dumping, piped outflow, and channeled waste streams as localized point sources, or as diffuse nonpoint sources they can enter rivers, lakes, streams, and groundwater through runoff and soil percolation. Nonpoint sources are considered to be major contributors to air, water, and soil pollution which include runoff from paved streets and parking lots, agricultural lots, soil erosion from logging, atmospheric deposition of acidic or toxic air pollutants (Table 1). The source is particularly... 

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