Environmental Hazard:

Soil Contamination

Soil contamination is the presence of man-made chemicals or other alterations in the natural soil environment. This type of contamination typically results from the rupture of underground storage tanks, application of pesticides, percolation of contaminated surface water to subsurface strata, leaching of wastes from landfills or direct discharge of industrial wastes to the soil. The most common chemicals involved are petroleum hydrocarbons, solvents, pesticides, lead and other heavy metals. This occurrence of soil contamination is correlated with the degree of industrialization and intensity of chemical usage.

The major concern with soiil contamination is that there are many sensitive land uses where people are in direct contact with soils, such as residences, parks, schools and playgrounds. Other contact mechanisms include contamination of drinking water or inhalation of soil contaminants which have vaporized. There is a very large set of health consequences from exposure to soil contamination depending on pollutant type, pathway of attack and vulnerability of the exposed population. Chromium and many of the pesticide and herbicide formulations are carcinogenic to all populations. Lead is especially hazardous to young children, in which group there is a high risk of developmental damage to the brain and nervous system, while to all populations kidney damage is a risk.

Chronic exposure to benzene at sufficient concentrations is known to be associated with higher incidence of leukemia. Mercury and cyclodienes are known to induce higher incidences of kidney damage, some irreversible. PCBs and cyclodienes are linked to liver toxicity. Organophosphates and carbamates can induce a chain of responses leading to neuromuscular blockage. Many chlorinated solvents induce liver changes, kidney changes and depression of the central nervous system. There is an entire spectrum of further health effects such as headache, nausea, fatigue, eye irritation and skin rash for the above cited and other chemicals. At sufficient dosages a large number of soil contaminants cause death.

Until about 1970 there was little widespread awareness of the worldwide scope of soil contamination or its health risks. Areas of concern, such as Love Canal, were often viewed as unusual or isolated incidents. In the U.S., passage of the National Environmental Policy Act in 1969 required careful analysis of the consequences of any federally funded project. Passage of The Resource Conservation and Recovery Act (RCRA) by the U.S. Congress in 1976 established guidelines not only for handling of hazardous materials but transport and hauling, such as required in cleanup of soil contaminants. In 1980 the U.S. Comprehensive Emergency Response Compensation and Liability Act (CERCLA) was passed to establish, for the first time, strict rules on legal liability for soil contamination. Not only did CERCLA stimulate identification and cleanup of thousands of sites, but it raised awareness of property buyers and sellers to make soil contamination a focal issue of land use and management practices; moreover, preparation of a Phase I Environmental Site Assessment has become standard practice for many parts of the western world and Japan.