Toxaphene


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Introduction

Toxaphene is an insecticide. Toxaphene was one of the most heavily used insecticides in the United States until most uses were banned in 1982 by the U.S. Environmental Protection Agency (EPA) because it has been shown to cause effects on human and animal health. It was used primarily in the southern United States to control insect pests on cotton and other crops. It was also used to control insect pests on livestock and to kill unwanted fish species in lakes. Since 1982, toxaphene is only allowed to be used on livestock and for emergency use (determined by EPA on a case-by-case basis) in the United States. In contrast, it is still commonly used to control insects on banana and pineapple crops in Puerto Rico and the Virgin Islands.

Toxaphene is a man-made mixture containing more than 670 chemicals. It is a yellow-to-amber, waxy solid that smells like turpentine. It does not burn and readily changes to vapor when in solution.

Toxaphene does not occur naturally in the environment. It is widely found in the environment, mainly as a result of past releases to air, water, and soil through its use as a pesticide. The forms of toxaphene commonly found in the environment are a gas in the atmosphere, a solid in soils and sediment, and in surface and groundwater. Toxaphene found near hazardous waste sites is usually a solid.

Structural diagram: National Institutes of Health


Fate & Transport

Toxaphene can be transported unchanged in the air for long distances from release sites. It is not rapidly broken down and will persist in air, soil, or water from weeks to years, depending on conditions that speed up its breakdown.

Toxaphene in soil will vaporize to air or stick to soil particles. Toxaphene does not dissolve easily in water; therefore, concentrations of the mixture in surface water and groundwater are very low. Toxaphene in surface water will vaporize to air or settle to sediments in the bottoms of lakes or streams.

Exposure Pathways

You can be exposed to low levels of toxaphene in food (particularly fish from contaminated water), drinking water, outdoor air, and contaminated soil at hazardous waste sites. Skin contact and inhalation of toxaphene in workplace settings were at one time important sources of human exposure. Except for exposure from use in emergency situations and from the treatment of livestock, inhalation and skin contact with toxaphene have become less common due to the cancellation of its use for most applications as a pesticide. However, skin contact is still possible from contaminated soil. Other historical sources of environmental releases include emissions from manufacturing facilities and disposal of pesticide products containing toxaphene.

At one time, background levels of toxaphene were reported to be about 1 part of toxaphene in one billion parts of air (ppb), 0.05 ppb toxaphene in surface water and 0.24 parts of toxaphene per one million parts (ppm) in some domestic cropland soils. However, these levels were measured before toxaphene's use was restricted.

Toxaphene has been measured in the following food sources: oils and fats, root vegetables (such as carrots), meats, grains, and fish. The average daily intake of toxaphene from contaminated food has been estimated to be 1.6 ug/day for an adult. The estimated average intake of toxaphene through inhalation of outdoor air is 0.4-0.33 ug/day. Current levels of toxaphene in foodstuffs and the environment are probably lower, but no information is available on current levels.

Metabolism

Toxaphene can enter your body through your lungs when you breathe air containing it, through your stomach and intestines after eating food or drinking water containing it, or through the skin. Studies in animals indicate that toxaphene enters the body quickly following exposure. Since toxaphene does not dissolve easily in water, and it does readily change to a vapor when in other solutions, the most significant route of exposure around hazardous waste sites is likely to be inhalation. However, contact with soil contaminated with toxaphene can also result in significant exposure for some people (e.g., children). Toxaphene may enter the body faster if it is taken in after a meal heavy in oil because oil helps toxaphene move from the stomach into the blood. Once toxaphene has entered the human body, it is rapidly broken down and removed. It does not appear to accumulate in the body to any appreciable degree. Almost all of the toxaphene taken into the body leaves quickly in the urine and feces within a few weeks.

Health Effects

Poisoning in people from breathing, eating, or drinking high levels of toxaphene for brief periods has been reported to cause damage to the lungs, nervous system, liver, and kidneys and can result in death. Limited evidence in humans suggests that exposure for longer periods to lower levels may also result in damage to the liver, kidneys, lungs, and nervous system in people.

Results from animal studies indicate that for short periods, exposure to high levels of toxaphene can damage all the organs listed above. The major organs or systems affected in laboratory animals by longer-term exposure to lower levels of toxaphene in animals are the liver, kidney, nervous system, adrenal gland, and immune system. The adrenal gland and immune system don't appear to be damaged by toxaphene in people. The severity of these effects is increased as people or animals are exposed to increasing levels of toxaphene.

An increased risk for cancer has been demonstrated in laboratory rodents exposed to high doses of toxaphene. Pregnant animals exposed to low levels of toxaphene by mouth did not become ill although birth defects were observed in their fetuses. Since these effects were seen in animals, it is also possible that they could occur in humans exposed to sufficient doses. However, we have no information to indicate that these effects do occur in humans.

Information excerpted from:

Toxicological Profile for Toxaphene December 1990

Agency for Toxic Substances and Disease Registry
U.S. Dept. of Health and Human Services