Propagation of Uncertainties in Soil and Pesticide Properties to Pesticide Leaching
- F. van den Berg *a,
- A. Tiktakb,
- G.B.M. Heuvelinka,
- S.L.G.E. Burgersc,
- D.J. Brusa,
- F. de Vriesa,
- J. Stolted and
- J.G. Kroesa
- a Environmental Sciences Group, Wageningen Univ. and Research Centre, PO Box 47, 6700 AA Wageningen, the Netherlands
b Netherlands Environmental Assessment Agency (PBL), PO Box 303, 3720 AH Bilthoven, the Netherlands
c Biometris, Wageningen Univ. and Research Centre, PO Box 47, 6700 AA Wageningen, the Netherlands
d Norwegian Institute for Agricultural and Environmental Research, Fredrik A. Dahls vei 20, N-1432 Ås, Norway. Assigned to Associate Editor Minghua Zhang
In the new Dutch decision tree for the evaluation of pesticide leaching to groundwater, spatially distributed soil data are used by the GeoPEARL model to calculate the 90th percentile of the spatial cumulative distribution function of the leaching concentration in the area of potential usage (SP90). Until now it was not known to what extent uncertainties in soil and pesticide properties propagate to spatially aggregated parameters like the SP90. A study was performed to quantify the uncertainties in soil and pesticide properties and to analyze their contribution to the uncertainty in SP90. First, uncertainties in the soil and pesticide properties were quantified. Next, a regular grid sample of points covering the whole of the agricultural area in the Netherlands was randomly selected. At the grid nodes, realizations from the probability distributions of the uncertain inputs were generated and used as input to a Monte Carlo uncertainty propagation analysis. The analysis showed that the uncertainty concerning the SP90 is 10 times smaller than the uncertainty about the leaching concentration at individual point locations. The parameters that contribute most to the uncertainty about the SP90 are, however, the same as the parameters that contribute most to uncertainty about the leaching concentration at individual point locations (e.g., the transformation half-life in soil and the coefficient of sorption on organic matter). Taking uncertainties in soil and pesticide properties into account further leads to a systematic increase of the predicted SP90. The important implication for pesticide regulation is that the leaching concentration is systematically underestimated when these uncertainties are ignored.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © 2012. . Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.