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Title: The loss of chlorfenvinphos from soil by leaching, and the effects of chlorfenvinphos on soil invertebrates
Author: Thompson, Alwyn Richard
Awarding Body: University of London
Current Institution: University of London
Date of Award: 1968
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The aim of this thesis was to study the persistence of an organophosphate insecticide, chlorfenvinphos, in soil, its movement from soil to neighbouring water and its effects on terrestrial and aquatic ecosystems. Chlorfenvinphos, formulated as an emulsion and granules, persisted in soil longer than most organophosphates but less than chlorinated hydrocarbons. Intense rain soon after soil was treated with chlorfenvinphos moved the insecticide on the surface of sloping land, but no residues were detected after 23 weeks in the water and mud in a pond at the bottom of the slope. Chlorfenvinphos moved more readily than dieldrin through soil in experimental troughs. Dieldrin seemed to be more firmly bound to soil particles and less easily desorbed than chlorfenvinphos. When chlorfenvinphos emulsion was applied to the surface of a pond, it was detected in the mud at the bottom after 5 hours and only 16% of the amount applied remained in the water after 19 hours. There were too few invertebrates in samples of mud to show statistical differences after treatment. Chlorfenvinphos disturbed the ecological equilibrium in soil between predatory mites, which became·fewer, and saprophagous oribatid mites and entomobryid springtails, which often increased in numbers after treatment. Toxicity tests in the laboratory showed that predatory mites were more susceptible to chlorfenvinphos than saprophagous species of microfauna. Chlorfenvinphos reduced numbers of predators more than those of saprophagous invertebrates. Numbers of Chilopoda were reduced more than Diplopoda and the initial dosage decreased numbers of Pauropoda, Diptera larvae and wireworms. Numbers of Protura, Symphyla, Enchytraeidae and Nematoda were unaffected by chlorfenvinphos at the dosage studied. Earthworms in treated plots were reduced only little more by chlorfenvinphos than by mechanical CUltivation. They did not accumulate residues after exposure to residues. The insecticide .eeemed to " have no significant effects on numbers of adult Carabidae and Staphylinidae in field plots. The observed effects of chlorfenvinphos on ecosystems to which it is applied and those to which it may be dispersed did not persist more than a year after treatment.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available