Bioconcentration and excretion of diazinon, IBP, malathion and fenitrothion by willow shiner

Abstract

Bioconcentration and excretion of diazinon (diethyl 2‐isopropyl‐4‐methyl‐6‐pyrimidinyl phosphorothionate), IBP (S‐benzyl diisopropyl phosphorothiolate), malathion (S‐1,2‐bis(ethoxycarbonyl)ethyl dimethyl phosphorothiolothionate) and fenitrothion (dimethyl 4‐nitro‐m‐tolyl phosphorothionate) was studied for the fresh‐water fish, willow shiner (Gnathopogon caerulescens). The concentrations of these pesticides in whole body of fish reached plateaus in 6–48 h exposure (IBP 6h, fenitrothion and malathion 24 h, diazinon 48 h). The average values of bioconcentration factors (BCF) in whole body of fish were 33.2 for IBP, 398.5 for fenitrothion, 34.4 for malathion and 247.9 for diazinon through the 168 h exposure period. The excretion rate constants from whole body offish were 0.07b‐1 for diazinon, 0.07b‐1 for fenitrothion and 0.49h‐1 for malathion assuming their processes to be first‐order kinetics. For IBP, the rate constant was 0.0017gng‐lh‐1 assuming the process to be second‐order kinetics.