Investigation of Biotoxicity and Environmental Impact of Prometryn on Fish and Algae Coexistent System

To investigate the toxic and environmental effects of prometryn, a laboratory experiment was performed on coexistent fish and algae. The body weight and length of Carassius carassius, Microcystis aeruginosa (M. aeruginosa) densities and water quality were measured continuously for 92 days. It was observed that fish growth was significantly inhibited by prometryn. This can be partly attributed to the adverse effects of prometryn on the antioxidant system of fish; the activities of superoxide dismutase (SOD) and catalase (CAT) in crucian carp were significantly inhibited by prometryn. The growth of M. aeruginosa was greatly inhibited by prometryn (p < 0.05), and the adverse effects of prometryn on M. aeruginosa indirectly impacted water qualities. The body weight and length of Carassius carassius first increased and then tended to be stable with increasing electrical conductivity (EC) values; their quantified relationship was established based on the Gompertz and Logistic equations (R2 = 0.920–0.989). Based on the above results, we concluded that the toxic effects of prometryn can impact the antioxidant system of fish and algae which in turn affects their growth performance, and have an indirect impact on water quality. The application of equations made it realizable to obtain a more detailed interpretation of the processes involved in these biological–abiotic interactions.