Comprehensive tracer studies on the environmental behavior of pesticides: The lysimeter concept - Effects and exposure assessment

Lysimeters using appropriate sizes and methodology has substantial potentia l to improve risk assessment. This potential for futural improvement of the basis for risk assessment includes, in addition to the assessment of the f ate of pesticides in soils and groundwater contamination, comprehensive stu dies for effects on flora, fauna and mesofauna as well as effects in the aq uifer. Major use of lysimeters at present practically is limited to fate an d leaching investigations. In the fate assessments mostly concentrations ar e considered, but the loading concept - with respect to critical loads - ma y be a complementary alternative. Practical use of lysimeters in pesticides registration basically is following a realistic worst case scenario concep t. Generic sets of scenarios considering data statistics and experimental u ncertainties would provide improved bases for comprehensive risk assessment s and for variations in time at one site, as well as for variations in time and space for regions. In the following, examples are given for other uses of lysimeters. The exam ples include one concerning accumulation in soil from multiple applications , one on lysimeter toxicity testing to improve the information on the ecoto xicological potential of residues in soil and examples on indirect use of l ysimeter data for the estimation of exposure in different regions (sensitiv ity of regions for pesticides leaching).