title: Occurrence of Chlorotriazine herbicides and their transformation products in arable soils.
abstract: Chlorotriazine herbicides (CTs) are widely used pest control chemicals. In contrast to groundwater contamination, little attention has been given to the circumstances of residue formation of parent compounds and transformation products in soils. Seventy-five cultivated floodplain topsoils in the Czech Republic were sampled in early spring of 2015, corresponding to a minimum of six months (current-use terbuthylazine, TBA) and a up to a decade (banned atrazine, AT and simazine, SIM) after the last herbicide application. Soil residues of parent compounds and nine transformation products were quantified via multiple residue analysis using liquid chromatography - tandem mass spectrometry of acetonitrile partitioning extracts (QuEChERS). Using principal component analysis (PCA), their relation to soil chemistry, crops and environmental parameters was determined. Of the parent compounds, only TBA was present in more than one sample. In contrast, at least one CT transformation product, particularly hydroxylated CTs, was detected in 89% of the sites, or 54% for banned triazines. Deethylated and bi-dealkylated SIM or AT residues were not detectable. PCA suggests the formation and/or retention of CT hydroxy-metabolite residues to be related to low soil pH, and a direct relation between TBA and soil organic carbon, and between deethyl-TBA and clay or Ca contents, respectively, the latter pointing towards distinct sorption mechanisms. The low historic application of simazine contrasted by the high abundance of its residues, and the co-occurrence with AT residues suggests the post-ban application of AT and SIM banned triazines as a permitted impurity of TBA formulations as a recent, secondary source. The present data indicate that topsoils do not contain abundant extractable residues of banned parent chlorotriazines, and are thus likely not the current source for related ground- and surface water contamination. In contrast, topsoils might pose a long-term source of TBA and CT transformation products for ground and surface water contamination.
authors.affiliation: Research Centre for Toxic Compounds in the Environment (RECETOX), Faculty of Science, Masaryk University, Kamenice 753/5, 625 00 Brno, Czechia; Institute for Environmental Biotechnology, Department for Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences (BOKU), Konrad-Lorenz-Strasse 20, 3430 Tulln, Austria. Electronic address: kerstin.brandstaetter-scherr@boku.ac.at.
authors.forename: Kerstin E
authors.initials: KE
authors.lastname: Scherr
authors.affiliation: Research Centre for Toxic Compounds in the Environment (RECETOX), Faculty of Science, Masaryk University, Kamenice 753/5, 625 00 Brno, Czechia.
authors.forename: Lucie
authors.initials: L
authors.lastname: Bielská
authors.affiliation: Central Institute for Supervising and Testing in Agriculture, Hroznová 2, Brno, 603 00, Czechia.
authors.forename: Petra
authors.initials: P
authors.lastname: Kosubová
authors.affiliation: AQUATEST Inc., Geologická 4, Praha 5, 152 00, Czechia.
authors.forename: Petra
authors.initials: P
authors.lastname: Dinisová
authors.affiliation: Research Centre for Toxic Compounds in the Environment (RECETOX), Faculty of Science, Masaryk University, Kamenice 753/5, 625 00 Brno, Czechia.
authors.forename: Martina
authors.initials: M
authors.lastname: Hvězdová
authors.affiliation: Research Centre for Toxic Compounds in the Environment (RECETOX), Faculty of Science, Masaryk University, Kamenice 753/5, 625 00 Brno, Czechia.
authors.forename: Zdeněk
authors.initials: Z
authors.lastname: Šimek
authors.affiliation: Research Centre for Toxic Compounds in the Environment (RECETOX), Faculty of Science, Masaryk University, Kamenice 753/5, 625 00 Brno, Czechia.
authors.forename: Jakub
authors.initials: J
authors.lastname: Hofman
mesh_terms: D000383:Agriculture; D001673:Biodegradation, Environmental; D018153:Czech Republic; D060587:Groundwater / Q000737:chemistry; D006540:Herbicides / Q000032:analysis* / Q000378:metabolism*; D010573:Pesticide Residues / Q000032:analysis* / Q000378:metabolism*; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis / Q000378:metabolism; D014227:Triazines / Q000032:analysis* / Q000378:metabolism*
chemical_list: D006540:Herbicides; D010573:Pesticide Residues; D012987:Soil; D012989:Soil Pollutants; D014227:Triazines
keywords: Atrazine; Biotransformation; Chlorotriazine herbicides; Fluvisols; Groundwater; Hydroxylated chlorotriazines; QuEChERS; Simazine; Sorption; Terbuthylazine; Water protection