Degradation of dichlorprop in soil under elevated ozone concentration

An aerobic degradation study was conducted to estimate possible effects of elevated ozone concentration in air on the behaviour of dichlorprop. An ave rage ozone concentration of 80 nL L-1 was chosen, which often occurs close to congested areas during late spring and summer. A control soil and an ozo ne exposed soil were kept under same conditions such as temperature, air fl ow and soil humidity. The use of C-14-labelled dichlorprop allows to examin e the fate of dichlorprop and follow the degradation products in soil. Exha ustive extraction of both soils yielded several fractions containing dichlo rprop residues. Half lives of dichlorprop of both treatments were found to be approximately 5 days. After 32 days most of the residues in soil remaine d in the non extractable fraction. The elevated ozone concentration showed no significant effects on the degradation behaviour of dichlorprop and its metabolites but significant differences were obtained for the behaviour of the nonextractable residues and of the release of carbon dioxide, which wer e higher for control soil in comparison to the ozone variant. These finding s suggest that even moderately elevated ozone concentration in air might ef fect mineralisation and fixation processes of dichlorprop.