Toxic Waste

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Toxic Waste

Introduction

Toxic substances, such as heavy metals and organic solvents, are often present in the waste stream produced by human activities. The chemical, petroleum, and mining industries are the most likely industries to produce toxic wastes, but they are also generated by domestic users, hospitals, and dry cleaners. Toxic waste can contaminate groundwater and possibly enter drinking water or the food chain.

Toxins have many different adverse effects on the body, from acute poisoning to the slow accumulation of cell defects over many years, which can lead to cancer. Environmental legislation has been enacted following instances of toxic waste harming human health, such as the famous incident at Love Canal in the 1970s. Those producing or handling toxic waste are now required to prevent its entering the public domain. But there are still many sites needing to be cleaned of toxic waste, and problems with generating, storing, and exporting it to developing countries.

Historical Background and Scientific Foundations

People often use the term toxic waste and hazardous waste interchangeably. But the U.S. Environmental Protection Agency (EPA) defines toxic waste as a type of hazardous waste, which is a material dangerous or potentially harmful to human health or the environment. The other types of hazardous waste are flammable, corrosive, or reactive waste. A toxic waste contains components that poison body cells or tissues, thereby producing adverse effects on health.

The petrochemical, chemical, metal, and mining industries produce most toxic wastes, but homes produce some too—garden pesticides and cleaning material are an important source. Toxic wastes can be present in the form of a solid, liquid, or gas and they may enter air, water, or soil. There are, therefore, a variety of ways in which humans can be exposed and a wide range of toxins. The United States Agency for Toxic Substances & Disease Registry lists arsenic, lead, mercury, vinyl chloride, and polychlorinated biphenyls (PCBs) as the most hazardous toxic wastes.

Impacts and Issues

The Industrial Revolution and the growth of the chemical industry brought many toxins into everyday use, long before medical research revealed their potential for harm to the cells of the body. Toxins often cause mutations in cells that can lead to birth defects, miscarriage, and cancer. Cancer may show up only many years after exposure. Chemicals found in toiletries, pesticides, and many other everyday products are now known to mimic the effect of the female hormone estrogen. Recent research has shown that these environmental estrogens cause developmental abnormalities in fish and may be linked to infertility and other human health problems.

The potential of toxic waste to harm was highlighted in events at Love Canal, Niagara Falls, New York, in the 1970s. In the 1920s, this area had been a landfill site for industrial chemicals. In the 1950s, around 100 homes and a school were built on the land. Twenty-five years later, the New York Times reported how the waste containers had rotted, allowing toxic waste to leach into the backyards of these homes. A higher than expected incidence of birth defects and miscarriages was noted in the local population, and many had higher than expected white cell counts, a possible precursor of leukemia. In the end, President Jimmy Carter declared a state of emergency and had the residents evacuated.

The Love Canal incident led to the Comprehensive Environmental Response, Compensation, and Liability Act, also known as the Superfund Act, in 1980. This legislation deals with the treatment and liability for these contaminated sites, the most seriously polluted of which are designated as Superfund sites.

Toxic waste continues to pose problems, but these are more likely to occur in developing nations that do not yet have tough environmental legislation. They may also be the recipients of toxic wastes from elsewhere. These exports continue, albeit illegally since a ban in 1989. In 2006, ten people died and thousands were made ill after exposure to petroleum waste exported to the Ivory Coast. In 2007, the Mattel toy company recalled almost two million toys from stores in the United States that were contaminated with lead-based paint; the source of the paint was traced to factories in China. China has also been accused of exporting toxic waste intended for use as components in fertilizer; Australian officials seized shipments of raw materials shipped from China and meant for fertilizers containing dangerously high levels of cadmium in 2003. Inside China, recent discharges of toxic waste into the Beijiang, Songhua, and Sungari Rivers all resulted in environmental emergencies that required the suspension of local water supplies.

WORDS TO KNOW

ENVIRONMENTAL ESTROGEN: Compounds in toxic waste that mimic estrogen in their effect on humans and other animals.

SUPERFUND: Legislation that authorizes funds to clean up abandoned, contaminated sites.

TOXIN: A substance which is harmful to the body.

BIBLIOGRAPHY

Books

Cunningham, W.P., and A. Cunningham. Environmental Science: A Global Concern. New York: McGraw-Hill International Edition, 2008.

Web Sites

U.S. Agency for Toxic Substances & Disease Registry. “2007 CERCLA Priority List of Hazardous Substances.” http://www.atsdr.cdc.gov/cercla/071ist.html (accessed July 10, 2008).

U.S. Agency for Toxic Substances and Disease Registry. “Toxic Substances Portal.” April 13, 2007.

http://www.atsdr.cdc.gov/substances/index.html (accessed April 7, 2008).

U.S. Environmental Protection Agency (EPA). “The Love Canal Tragedy: EPA History.” January 1979. http://www.epa.gov/history/topics/lovecanal/01.htm (accessed March 17, 2008).

Environmental Science: In Context