1 research outputs found
Large Scale Risks from Agricultural Pesticides in Small Streams
Small streams are important refuges
for biodiversity. In agricultural areas, they may be at risk from
pesticide pollution. However, most related studies have been limited
to a few streams on the regional level, hampering extrapolation to
larger scales. We quantified risks as exceedances of regulatory acceptable
concentrations (RACs) and used German monitoring data to quantify
the drivers thereof and to assess current risks in small streams on
a large scale. The data set was comprised of 1 766 104
measurements of 478 pesticides (including metabolites) related to
24 743 samples from 2301 sampling sites. We investigated the
influence of agricultural land use, catchment size, as well as precipitation
and seasonal dynamics on pesticide risk taking also concentrations
below the limit of quantification into account. The exceedances of
risk thresholds dropped 3.7-fold at sites with no agriculture. Precipitation
increased detection probability by 43%, and concentrations were the
highest from April to June. Overall, this indicates that agricultural
land use is a major contributor of pesticides in streams. RACs were
exceeded in 26% of streams, with the highest exceedances found for
neonicotinoid insecticides. We conclude that pesticides from agricultural
land use are a major threat to small streams and their biodiversity.
To reflect peak concentrations, current pesticide monitoring needs
refinement