Sources Of Hazardous Wastes
Hazardous wastes can be solids, gases, liquids, or semi-liquids like mining sludge and drilling mud. Most of the wastes listed by the EPA are liquids or semi-liquids. Thousands of waste materials are considered hazardous. These include familiar items like used motor oil and mercury, agricultural pesticides, and industrial materials such as asbestos and polychlorinated biphenyls (PCBs). United States industries, farms, mines, military facilities, cities, and small businesses generate roughly 200 million tons of hazardous wastes each year. Furthermore, the EPA estimates that there are presently 6,500 facilities in the United States that require hazardous waste clean-up under the directives of the 1976 Resource Conservation and Reclamation Act (RCRA) and its 1984 Hazardous and Solid Waste Amendments (HSWA).
Hazardous waste management is also an international issue. Each year, industrialized nations with strict environmental regulations export more than two million tons of hazardous waste for disposal in poorer developing nations with less stringent waste disposal oversight. Developed nations also locate large corporate, industrial, and military facilities in countries that have lax environmental restrictions.
Hazardous wastes often cause problems for years after their disposal. Many industrial waste disposal sites were established, filled, and buried long before establishment of present-day standards for management and disposal of hazardous chemicals. Toxic, flammable, corrosive, and reactive chemicals are often long-lived, and sometimes the dangers they posed to the environment and to human health were unknown at the time of their disposal. The industries responsible for many pre-1970 hazardous waste sites are no longer in business, and sometimes the sites themselves are difficult to locate. Even modern legislation gives industries fairly broad leeway to produce chemicals, police their own waste disposal practices, and to contest cases of possible environmental or human health damage. It is often extremely difficult to prove a scientific link between an incident of drinking water poisoning, or a human disease cluster, and a facility that improperly handles industrial chemicals.
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