Use of small artificial ponds for assessment of hazards to aquatic ecosystems

Abstract

Field tests with natural ponds often lack sufficient replication and/or control, making interpretation and evaluation of results difficult. For the assessment of potential hazards of chemicals to aquatic ecosystems, small artificial ponds have become increasingly valuable. Artificial pond ecosystems should, as far as possible, reflect natural conditions, contain all trophic levels with a high diversity of organisms, and, most importantly, be logistically and experimentally manageable. To fulfill these conditions, 5-m3-volume ponds, interconnected by closable locks, were provided with natural lake sediment and well water. Caged fish were added to each pond, and the interconnecting locks were kept open until identical physicochemical and biological conditions had been established. At this time, the ponds were isolated from one another and experiments with a pyrethroid insecticide (Baythroid®) containing cyfluthrin as the active ingredient (a.i.) were conducted. The results of these field tests, which include both the fate and the biological effects of the insecticide, were compared with data obtained in larger natural ponds. Overall, the results were similar, indicating that useful information on the potential hazard of chemicals can be obtained in small artificial ponds.