The fate and bioavailability of currently used and emerging pesticides in agriculturally used
                       fluvisols - effects of soil and pesticide properties


 Marek Šudoma^1, Natalia Neuwirthová^1, Markéta Svobodová^1, Lucie Bielská^1, Martina Hvězdová^1,
            Zdeněk Šimek^1,  Lucia Škulcová^1, Kerstin E. Scherr^2 and Jakub Hofman^1*


 ^1 Research Centre for Toxic Compounds in the Environment (RECETOX), Faculty of Science, Masaryk
                      University, Kamenice 753/5, 625 00 Brno, Czech Republic

   ^2 Institute for Environmental Biotechnology, Department for Agrobiotechnology, University of
       Natural Resources and Life Sciences, Konrad-Lorenz-Strasse 20, A-3430 Tulln, Austria


                          * corresponding author: hofman@recetox.muni.cz


Keywords: Conazole fungicides, microcosm, bioavailability


The class of conazole fungicides (CFs), among them epoxiconazole, tebuconazole, flusilazole and
prochloraz are currently used pesticides and members of the triazole group, used as broad-spectrum
fungicides that inhibit ergosterol biosynthesis and are typically applied as foliar sprays for
cereals, sugar beet or oilseed rape (Li et al., 2015). Conazole fungicides are widely used in EU
countries and their residues are frequently found in European arable soils (Hvězdová et al., 2017)
which corresponds to their environmental properties. CFs are strongly sorbed to soil (logK[OC] of
3–4) and have low to moderate water solubility (S[W] of 7–150 mg/L).They are very persistent in
soils and tend to form long-term residues as their typical DT[50] values range from 120 days to 1
year (Lewis et al., 2016). These attributes predetermine them to be highly bioaccumulative and
hazardous.

However, in real ecosystems, complex interactions occur (between pesticides, soil, microbes,
earthworms, plants...) and these are poorly understood. Hence, in this contribution (poster), we
would like to present the novel microcosm experiment, where the combined effects of soil
properties, microorganisms, plants and earthworms on CF multimedia fate and bioavailability were
evaluated.

In particular, the CF fate (by means of total, desorbable and freely dissolved concentrations) and
bioavailability (by means of uptake to model fauna, flora and passive samplers) is studied in
complex microcosm systems consisting of agriculturally used fluvisols under the addition of
selected  model compounds (epoxiconazole, tebuconazole, flusilazole,  prochloraz) at background
levels (0.5 mg/kg), seeding plants (Lactuca sativa), earthworms (Eisenia fetida), SPME passive
sampling fibers, Silicon rubber sheets and Chemcatcher^® passive samplers.

A subset of 10 fluvisols was selected based on the DRIFT mid infrared portion using the
Kennard-Stone algorithm (Stevens et al., 2013). These 10 soils are representative of a large
fluvisols range in terms of their qualitative and quantitative SOM properties (TOC, DOC, HA,FA,
WHC, pH, texture, etc.).


Acknowledgments:

This research is funded by the Czech Science Foundation (GAČR) grant number 15-20065S. This work
was also partly supported by the Czech Ministry of Education, Youth and Sports (LO1214 and
LM2015051).

References:

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