Fungicide
Field Concentrations Exceed FOCUS Surface
Water Predictions: Urgent Need of Model Improvement
- Publication date
- Publisher
Abstract
FOCUS
models are used in European regulatory risk assessment to
predict the frequency and magnitude of individual pesticide surface
water concentrations. A recent study showed that these models are
not protective in the prediction of insecticide concentrations in
surface waters and sediments. Since fungicides differ with regard
to their physicochemical properties, application patterns, and entry
routes, we compared a larger data set of 417 measured field concentrations
(MFC) of agricultural fungicides in surface waters and sediments from
56 studies to the respective predicted environmental concentrations
(PEC) calculated with FOCUS step 1–4. Although the fraction
of the underestimation of fungicide MFC values was generally lower
than that obtained for insecticides, 12% of step 3 and 23% of step
4 PECs were exceeded by surface water MFCs. Taking only the 90th percentile
concentration of every substance and only E.U. studies into account
(E.U. studies: <i>n</i> = 327; 90th percentile + E.U. studies: <i>n</i> = 136), a maximum of 25% of the step 3 and 43% of the
step 4 PECs were exceeded by surface water MFCs, which is an even
worse outcome than that obtained for insecticides. Our results demonstrate
that FOCUS predictions are neither protective nor appropriate for
predicting fungicide concentrations in the field in the context of
European pesticide risk assessment