Modern tools and approaches to study fate and bioavailability of pesticides in soils and related
environmental compartments

Marek Šudoma

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

Supervisor: Doc. RNDr. Jakub Hofman, Ph.D.


Current systems of agricultural management and crop production indispensably rely on the use of
herbicides, fungicides and insecticides. Although the soul idea of pesticide as a substance is to
reach the target organism, make the intended effect and then quickly disappear, their residues can
be found in the environment even long time after application. Moreover, due to their persistency
and global long range transport it is often possible to find them in areas, where they have been
never applied. After discoveries of dangerous properties of DDT and other organochlorine
pesticides, a number regulations including Stockholm Convention (UNEP, 2016) were adopted which
prohibited or significantly limited their production and use. However, the continuing need for
plant protection products has resulted in parallel development of other types of pesticides
(including those currently used - CUPs) again leading to a constant flow of heterogeneous
substances into environment. Despite the fact that there are many non-bioaccumulative (logK[OW] <
0), non-persistent, quickly degradable CUPs (MCPA, 2,4-D, glyphosate, chlormequat, etc.), there are
also CUPs for which bioaccumulation and persistency in soils can be expected, based on their K[OW],
K[OC], and DT[50] (Lewis et al., 2016). However, in real ecosystems, complex interactions occur
(between pesticides, soil, microbes, earthworms, plants...) and these are poorly understood. Hence,
in this contribution (lecture), the novel microcosm experiment will be described, 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) was 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.