Oxadiazon Residues in Surface Water and Crucian Carps (Carassius Cuvieri) of Lake Kojima

Abstract

In order to study the fate of oxadiazon in the field, the residue level in river water and crucian carps was investigated in the area near Lake Kojima where a large amount of it was applied. The sampling period was from 1980 to 1982. All the year oxadiazon was detected in the surface water of Lake Kojima, the Sasagase and the Seno River. Moreover, it was also detected in crucian carps living in Lake Kojima. The level was several hundred times higher in the latter than the former. Time course of the level in crucian carps showed a very similar pattern to that in river water, which indicated that the residue level reflected directly the level of contamination of the water in which they live, almost without any time lag. The values of biological concentration factor were mostly in the range 200-400 irrespective of whether the level in fish is low or high. The degradation experiment in the model system showed that oxadiazon might be very stable in the environment. This result compared well with that in the field. Mass spectrometry and mass chromatography identified oxadiazon from the crucian carps (March 12, 1981) in which 0.017ppm was detected on ECD gaschromatogram.