From the viewpoint of residues, could currently used pesticides from “contaminated sites”
of agricultural soils release into the water?

Research Centre for Toxic Compounds in the Environment, Masaryk University, Brno, Czech Republic^1)

Central Institute for Supervising and Testing in Agriculture, Brno, Czech Republic^2)

Institute for Environmental Biotechnology, University of Natural Resources and Life Science,
Vienna, Austria^3)

Martina Hvězdová*^1), Petra Kosubová^2), Zdeněk Šimek^1), Kerstin Brandstätter-Scherr^3)^

                              Jakub Hofman^1) hofman@recetox.muni.cz

Key words: soils, currently used pesticides, monitoring

Currently used pesticides (CUPs) used in agriculture and their transformation products have been
found at high frequency and at considerable concentrations in monitoring of surface and groundwater
repeatedly. But data for pesticides in soils are not available, although soils can be expected to
be a source of pesticides for water contamination. The monitoring of CUPs in Czech agricultural
soils was performed in 2015, not only for the purpose above, but also for the post-registration
control of approved plant protection products. Seventy active ingredients and 21 transformation
products were determined by multiple residue method using QuEChERs extraction and UPLC-MS/MS
detection in 75 soils. Several CUPs were found above LOQ frequently: among the most frequently
belong azole fungicides: epoxiconazole (36% of samples), tebuconazole (27%), flusilazole (17%),
prochloraz (16%), and propiconazole (10%). Their mean concentrations were about 0.01 mg/kg (i.e.
Czech limit for pesticides in agricultural soils) in positive samples. The 2-hydroxy atrazine was
the second most frequently detected compound (29%) with mean concentration about 0.03 mg/kg in
positive samples and the highest measured concentration of 0.135 mg/kg. Other CUPs with frequent
findings were simazine-2-hyroxy (44%), terbuthylazine-hydroxy (83%) and others. The results also
show that residues of CUPs are present as the mixture in current agricultural soils - half of the
soils had 5 or more CUPs detected. The soil residues of CUPs should be definitely considered and
soil monitoring programs for CUPs should be initiated in EU countries along with water monitoring.
Financial support was obtained from GACR project 15-20065S.