RESISTANCE OF THE TOXAPHENE INSECTICIDE IN SOIL
Abstract
Introduction. Toxaphene is resistant to degration and has been known as persistent bioaccumulator. In oder to understand the persistence and degradation phenomena of toxaphene in soil a series of tests were run.
Methods. All experiments for dry and moist soil were conducted with 10 to 20 kg soil samples, contained in plastic tubs. The experiment was carried out in two parts. The five samples studied in each part are described below. Part I: "Dry samples". Soil control I soil amended with 10 percent gin trash/soil amended with 25 percent gin trash/soil amended with 10 percent gin trash and treated with 500 ppm toxaphene and soil treated with 500 ppm toxaphene. These samples were kept dry during the entire experimental period. Part II: "Moist samples". The samples were the same as described in part I, but they were kept moist by addition of water weekly during the experimental period.
Periodically twenty grams of soil were analyzed using a gas chromatograph.
Results. Chromatograms of dry and moist samples from soil containers (Part I and II) analyzed up to 12 months after initiation of the experiments showed that no toxaphene degradation or dissipation had occurred. GLC profiles of extracts of 12 months soil samples were identical to those of 0 dry samples and almost 100 percent of toxaphene was recovered in all samples after one year regardless of whether samples were dry or moist I amended or not.
Discussion. The results suggest that toxaphene dose not undergo degradation in soil" under aerobic condition, so it can be a persistent insecticide in soil under environmental condition.
Methods. All experiments for dry and moist soil were conducted with 10 to 20 kg soil samples, contained in plastic tubs. The experiment was carried out in two parts. The five samples studied in each part are described below. Part I: "Dry samples". Soil control I soil amended with 10 percent gin trash/soil amended with 25 percent gin trash/soil amended with 10 percent gin trash and treated with 500 ppm toxaphene and soil treated with 500 ppm toxaphene. These samples were kept dry during the entire experimental period. Part II: "Moist samples". The samples were the same as described in part I, but they were kept moist by addition of water weekly during the experimental period.
Periodically twenty grams of soil were analyzed using a gas chromatograph.
Results. Chromatograms of dry and moist samples from soil containers (Part I and II) analyzed up to 12 months after initiation of the experiments showed that no toxaphene degradation or dissipation had occurred. GLC profiles of extracts of 12 months soil samples were identical to those of 0 dry samples and almost 100 percent of toxaphene was recovered in all samples after one year regardless of whether samples were dry or moist I amended or not.
Discussion. The results suggest that toxaphene dose not undergo degradation in soil" under aerobic condition, so it can be a persistent insecticide in soil under environmental condition.
Keywords
Toxaphene, Soil, Toxaphene Degradation, Organochlorine Insecticides, Organic pollutants, Microorganisms, Microbial degradation