Threshold toxicity and repeated exposure studies of dichlorvos to the larvae of the common lobster (Homarus gammarus L.)
1996; Elsevier BV; Volume: 34; Issue: 3 Linguagem: Inglês
10.1016/0166-445x(95)00041-2
ISSN1879-1514
AutoresJ.G. McHenery, Christine H. Francis, I.M. Davies,
Tópico(s)Insect and Pesticide Research
ResumoA series of tests were conducted on larvae of the common lobster, Homarus gammarus, to determine their sensitivity to dichlorvos (0,0-dimethyl-2,2-dichlorovinyl phosphate, DDVP), the active ingredient of Aquagard® (Ciba-Geigy Agrochemicals, Cambridge, UK) a product administered to farmed fish as a treatment for sea lice (Lepeophtheirus salmonis Krøyer and Caligus elongatus Nordmann) infestation. The acute toxicity threshold (NOEC after 23 days exposure) of dichlorvos to stage 4 larvae was 0.63 μg l−1 DDVP. Acetylcholinesterase activity in exposed larvae was not significantly different from that in controls at concentrations up to 0.16 μg l−1 DDVP. Lobster larvae were able to tolerate and recover from extended exposure to sub-lethal concentrations. Exposure of stage 4 larvae to 50 μg l−1 dichlorvos for 6 h resulted in significant inhibition of acetylcholinesterase. Whilst AChE levels recovered after such exposure, repeated dosing at this level resulted in further inhibition and mortalities. Exposures to 25 μg l−1 DDVP for two 6-h periods resulted in AChE inhibition, although no significant mortalities were observed. Five exposures to 50 μg l−1 DDVP for 1-h periods also resulted in AChE inhibition, but no mortalities. The data are discussed in relation to DDVP dispersion simulation field experiments, and patterns of DDVP use.
Referência(s)