Hazardous wastes are chemicals and chemical by-products that can endanger human health or pollute the environment. Each year, the world’s factories and other sources produce billions of tons of wastes. A little more than 1 percent is hazardous. Industrialized countries produce about 90 percent of hazardous wastes.
In the United States, hazardous wastes are defined by the Resource Conservation and Recovery Act of 1976 and its 1984 amendments. Waste is declared hazardous if it corrodes (wears away) other materials; explodes; is easily ignited; reacts strongly with water; is unstable to heat or shock; or is poisonous. Poisonous wastes are commonly called toxic wastes. The law also covers radioactive wastes that occur as by-products of mining operations or as a result of the use of radioactive substances in medical procedures. Radioactive wastes from commercial power plants and other nonmilitary sources are controlled by the Nuclear Regulatory Commission (see Nuclear energy (Wastes and waste disposal) ). The Department of Energy controls the disposal of radioactive wastes from military sources.
Producers of hazardous wastes
include industries, hospitals, laboratories, and other establishments. Factories, especially chemical plants, account for most of the wastes. Nearly all manufacturing results in a small amount of hazardous waste. For example, making plastics yields harmful organic compounds (substances containing carbon). Oil refining produces potentially harmful acids, ammonia, and sludge (muddy deposits), which may contain chemicals or heavy metals.
Effects of hazardous wastes.
Harmful chemicals can pollute ground water—that is, water beneath the land’s surface. Most rural areas and many cities depend on ground water for their drinking supplies. Some hazardous wastes have also polluted rivers or lakes, killing fish and water plants and endangering water supplies.
Certain wastes could contaminate food and thus poison people or animals. Toxic wastes could poison people or animals through touch or smell. Certain wastes may pollute the air or create a fire hazard.
Disposal of hazardous wastes.
Many industries safely dispose of hazardous waste. One disposal method, called landfilling, involves storing harmful substances underground. A landfill must have a double lining of nonporous substances, such as clay and plastic, through which liquid cannot pass. Some industries recycle their hazardous wastes or use the wastes of other industries as raw materials. Another disposal method, called bioremediation, involves the use of bacteria that break down certain wastes, producing harmless substances. Also, burning some hazardous organic compounds at high temperatures makes them harmless.
The Resource Conservation and Recovery Act concerns the reduction, safe management, and disposal of hazardous wastes in the United States. It particularly encourages recycling such wastes, if possible, to recover useful materials. The Comprehensive Environmental Response, Compensation, and Liability Act of 1980, also called “Superfund,” has provided billions of dollars to clean up unsafe dump sites. Federal law requires state and local governments to have emergency plans for responding to accidental releases of toxic wastes. The law also requires businesses to reveal hazardous wastes present at their facilities.
