Toxaphene

Synonyms and Trade Names (partial list): Alltex, Alltox, Attac 4-2, Attac 4-4, Attac 6, Attac 6-3, Attac 8, Camphechlor, Camphochlor, Camphoclor, Chemphene M5055, chlorinated camphene, Chloro-camphene, Clor chem T-590, Compound 3956, Huilex, Kamfochlor, Melipax, Motox, Octachlorocamphene, Penphene, Phenacide, Phenatox, Phenphane, Polychlorocamphene, Strobane-T, Strobane T-90, Texadust, Toxakil, Toxon 63, Toxyphen, Vertac 90%.
Appearance: Yellow, waxy solid with a chlorine/terpene-like odour.

Overview

Toxaphene is a nonsystemic and contact insecticide that was used primarily on cotton, cereal grains fruits, nuts and vegetables. It has also been used to control ticks and mites in livestock. Toxaphene has been in use since 1949 and was the most widely used insecticide in the USA in 1975.

Toxaphene is highly insoluble in water and has a half life in soil of up to 12 years. It has been shown to bioconcentrate in aquatic organisms and is known to undergo atmospheric transport.

Toxaphene has been banned in 37 countries, including Austria, Belize, Brazil, Costa Rica, Dominican Republic, Egypt, the EU, India, Ireland, Kenya, Korea, Mexico, Panama, Singapore, Thailand and Tonga. Its use has been severely restricted in 11 other countries, including Argentina, Columbia, Dominica, Honduras, Nicaragua, Pakistan, South Africa, Turkey, and Venezuela.

Usage in South East Asia

 

Used or Found in Country?

Years of Usage

Regulatory Controls

Cambodia

   

Banned

Lao PDR

   

Banned in 1992

Malaysia

   

Banned

Thailand

Yes

1959

Banned in 1983

Indonesia

   

Banned in 1980

Philippines

   

Banned in 1989

Viet Nam

   

Banned in 1995

(table references)

Human Exposure

In a human volunteer study, twenty-five subjects were exposed to approximately 1 mg Toxaphene/kg body weight/day in a closed chamber to an aerosol of Toxaphene for a total of 13 days. Physical examination, blood and urine tests did not reveal any toxic effects. I

n a separate study, eight women working in an area that had been sprayed with Toxaphene at a rate of 2 kg/ha had a higher incidence of chromosome aberrations (acentric fragments and chromatid exchanges) than in control individuals. Annual physical examination of 137 workers involved in the manufacture of Toxaphene did not reveal adverse effects associated with the exposure. Similarly, a mortality survey of 199 employees who had worked with Toxaphene found that none of the deaths appeared to be directly related to the exposure.

IARC has concluded that while there is inadequate evidence for the carcinogenicity of Toxaphene in humans, there is sufficient evidence in experimental animals. IARC has classified Toxaphene as a possible human carcinogen (Group 2B).

Animal Exposure

The acute oral toxicity of Toxaphene is in the range of 49 mg/kg body weight in dogs to 365 mg/kg in guinea pigs.

In a 13-week study, rats were fed diets containing Toxaphene. Liver/body weight ratio and hepatic microsomal enzyme activities were increased in rats fed 500 ppm. Dose dependent histological changes were observed in the kidney, thyroid and liver. The NOAEL was determined to be 4.0 ppm (0.35 mg/kg).

In another study, beagle dogs were fed Toxaphene for 13 weeks. The liver/body weight ratio and serum alkaline phosphatase were increased in dogs fed 5.0 mg/kg. Mild to moderate dose dependent histological changes were observed in the liver and thyroid. The NOAEL for dogs was determined to be 0.2 mg/kg.

Male and female rats were fed Toxaphene in their diets for a total of 13 weeks in a one generation-two litter reproduction study. Effects in both the F0 and F1 adults at levels from 20 to 500 ppm included increased liver and kidney weight, and histological changes in the thyroid, liver and kidney.

Female ring-necked pheasants exposed to 300 mg Toxaphene/kg diet experienced reductions in egg laying and hatchability.

Plant Exposure

Toxaphene is essentially nontoxic to plants. In general, toxic effects have been observed only at levels much higher than the recommended usage level.

Aquatic Organism Exposure

Toxaphene is highly toxic, with 96-hour LC50 values in the range of 1.8 µg/L in rainbow trout to 22 µg/L in bluegill.

Brook trout exposed to Toxaphene for 90 days experienced a 46% reduction in weight at 0.039 µg/L, the lowest concentration tested. Egg viability in female trout was significantly reduced upon exposure to a concentration of 0.075 µg/L or more. Long term exposure to 0.5 µg/L reduced egg viability to zero.

BioAccumulation

The half-life of Toxaphene in soil ranges from 100 days up to 12 years, depending on the soil type and climate. This persistence, combined with a high partition coefficient (log KOW = 3.23-5.50) suggests that Toxaphene is likely to bioconcentrate. Bioconcentration factors of 4,247 and 76,000 have been recorded in mosquito fish and brook trout, respectively.

The chemical properties of Toxaphene (low water solubility, high stability, and semi-volatility) favour its long range transport, and Toxaphene has been detected in Arctic air.

Exposure of the general population is most likely through food, however levels detected are generally below maximum residue limits. Due to its being banned in many countries, recent food surveys have generally not included Toxaphene and hence recent monitoring data are not available.

For more information:


 

References:

Adapted from Persistent Organic Pollutants: Information on POPs, their alternatives and alternative approaches (United Nations Environmental Programme (UNEP) 1995).

Chemical structure of Toxaphene
Source: UNEP
Hatfield Consultants The World Bank funded by the Canadian POPs Trust Fund through the      
Canadian International Development Agency
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