Status and environmental impact of toxaphene in the Third World — A case study of African agriculture

Abstract

Toxaphene was early introduced to Egypt by Hercules Co. in 1955 to combat the main cotton insect pests: the cotton leaf worm Spodoptera littoralis, the pink bollworm Pectinophera gossypiella, and the spiny bollworm Earias insulana. Formulated Emulsfiable concentrate (E.C.). Toxaphene (60% Chlorinated camphene) was used in four successive sprays during the cotton season on an area of 1.5 million acres at the rate of 2L/acre during the first three seasons (1956–1958). The rate was then increased to 3L/acre during the next two seasons (1959–1960). In the 1961 season, a disaster occurred when toxaphene even at 4L/acre failed to stop the infestation outbreak of the cotton leaf worm resulting in a loss of 50% of the national cotton yield of that season. This failure was caused by the build up of cotton leaf worm resistance to toxaphene. The total amount of toxaphene used during these six seasons was estimated to be 54,000 metric tons of the active ingredient. Although the use of Toxaphene in Egypt was banned in 1962 due to the irreversible cotton leaf worm resistance, new sources of toxaphene residues kept comming to Egypt across the River Nile Basin countries which were still heavily using toxaphene (Sudan, Ethiopia, Tanzania and Congo). As well, the illegal use of toxaphene by fishermen was another source of toxaphene pollution. The residues of toxaphene seem to be quite persistent as shown by the few studies carried out. Levels up to 10 ppm were detected in the River Nile water, soil and other biological samples in the Egyptian environment. (Saleh, 1981). Long term exposure to sublethal levels are expected to be a potential hazard to human health and the environment. A follow up program to monitor and assess the risk and hazards of toxaphene exposure is suggested for implementation in Egypt as a model for developing countries heavily exposed to toxaphene residues.