Abstract
A study was undertaken to elucidate the relation between the mortality of tiger shrimp Penaeus japonicus and the accumulation of fenitrothion (FS) and its oxo-form (fenitrooxon, FO) in the shrimp during the exposure to FS at lethal level, and also to estimate the lethal concentrations in vivo of FO and FS by intramuscular administration to the shrimp.
The amounts of [14C] FS and its metabolites extracted with benzene from the surviving and dead shrimps during exposure to 2 ppb [14C] FS-sea water were determined by thin-layer co-chro-matography with non-radioactive FS and its authentic metabolites. In comparison with the amounts of FS and FO found in the surviving and dead shrimps, the major cause for the occur-rence of high mortality was presumed to be FO rather than its parent compound FS, and the estimated lethal concentration of FO was ca. 14 pmol/g-body weight.
From another experiment on the toxicity of FO and FS intramuscularly administered to the shrmp, the minimum lethal concentrations of FO and FS in vivo in tiger shrimp were estimated to be 8-20 pmol/g and ca. 200 pmol/g-body weight, respectively.
