DT50 data.xlsx (50.22 kB)

Dataset for: Dissipation of plant protection products from foliage

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posted on 24.04.2018, 08:14 by Markus Ebeling, Magnus Wang
In the environmental risk assessment for plant protection products in the EU a foliar dissipation half life (default DT50) of 10 days is considered for the risk assessment of birds and mammals feeding on sprayed foliage. This generic DT50 of 10 days is based on a compilation of residue trials conducted over 30 years ago, in which many compounds and formulations were considered that are not used any more. We have therefore reassessed foliar dissipation based on a dataset of 396 residue trials covering 30 compounds. Foliar dissipation half lives were calculated and potential factors determining dissipation were analysed, such as crop group, residue zone or rainfall. The strongest source of variability was found between individual trials. Other factors, including the residue zone or crop groups did not have a significant impact on dissipation. Only heavy rainfall (>6.5 mm/day, i.e. the 95th percentile rainfall) had a statistically significant influence, although rainfall explained only about five percent of the overall variability. Moderate rainfall (≤6.5 mm/day) did not significantly correlate with dissipation and explained only 0.1 percent of the overall variability. Most importantly, the differences in DT50 between crops and residue zones were neither marked nor statistically significant, hence trials from different residue zones and crops could be pooled to obtain more robust half lives. Over all compounds, trials, zones and crops the geometric mean DT50 was 3.2 days (90th percentile: 7.9 days).