Statistical distribution of pesticide concentrations in leachate results of a Monte-Carlo analysis performed with pelmo

The effect of the variation of climatic input parameters on the leaching of pesticides has been analysed in this study. In order to consider regional differences a total of 13 regions in Germany has been selected each with daily precipitation and temperature data over a period of 30 years. Based on this data set Monte-Carlo simulations have been performed for spring as well as for autumn applications. Fluctuations of pesticide concentrations in the leachate simulations were studied for three classes of pesticides with mean annual concentrations of about 0.01 μg/L, 0.1 μg/L, and 1.0 μg/L. Independent on the scenario the fluctuations decreased with increasing leaching potential. The geometric standard deviation for pesticide concentrations of 1.0 μg/L was in the range of 1.6 to 2.4. However, simulations with an example pesticide demonstrated that the differences between different scenarios were of higher importance than differences due to variance of climate within a given scenario.