AGROCHEMICAL FATE AND EFFECTS IN TERRESTRIAL, AQUATIC AND ESTUARINE ECOSYSTEMS

摘要

Characterization and control of non-point source pollution has been less successful than corresponding efforts directed at point source pollution. Sampling of non-point source pollution is complicated by the diffuse and episodic dispersal of chemical residues. Standardized bioassays do not adequately simulate episodic exposures to realistic concentrations of toxic substances. A description is given of a quantitative approach to chemically and physically characterizing non-point source pollutants and an illustration of how this approach could be utilized to design bioassays that characterize the biological impact of non-point source pollutants. The methods described include analysis of pesticide datasets, phytoplankton growth assays and daphnid survival and mobility assays. The atrazine and chlorpyrifos concentrations in the Maumee River during 1983 were used to generate exceedancy plots. These data were used with toxicity data to compute the probable periods of biological stress and recovery. Selenastrum capricornutum demonstrated a threshold population growth rate response to 10 μg/L of atrazine. Recovery from exposure to as much as 50 μg/L of atrazine was nearly