トキサフェン

Toxaphene is an organochlorine insecticide that is similar to other compounds such as endrin, dieldrin, aldrin, dichlorodiphenyltrichloroethane (DDT), lindane, and chlordecone. Manufacturing of toxaphene was started in the 1940s and was highly effective on cotton and certain food crops. In addition to its use as an insecticide, toxaphene was also used to eliminate certain species of fish in aquatic environments. Toxaphene itself consists of a mixture of hundreds of different chemicals with a major identified toxic component being heptachlorobornane. The use of toxaphene peaked in 1974 after DDT was banned in 1972 with nearly 400 000 metric tons being distributed into the environment (both land and aquatic uses). This use began to subside, yet nearly 100 000 metric tons was still used in 1980 shortly before the complete ban on toxaphene usage. Large quantities of toxaphene were released into the environment. The overall chlorine content of toxaphene is nearly 70% by weight with most of the organic compounds comprising toxaphene being chlorinated. The molecular weight of the various components of toxaphene can range from 308 to 551 g mol^-1. The mean formula weight is approximately 414 g mol^-1. Toxaphene can be found as an yellowish-waxy substance that is relatively volatile and can be transported in the atmosphere. If inhaled, especially in larger quantities, toxaphene has been shown to cause significant damage to the lungs/respiratory tract, central nervous system, and kidneys. The use of toxaphene as an insecticide was banned in the early 1980s and completely banned in the United States in 1990. In addition to its ban in North America, toxaphene has been also banned in Europe, yet its use in developing countries still persists. Toxaphene is not readily soluble in water and tends to deposit in the soil and sediment, as well as the atmosphere. Microorganisms in the soil tend to degrade toxaphene very slowly. Toxaphene does not degrade as slowly as DDT but has been demonstrated to persist in the environment for extended and significant periods of time.