Intra aquifer variations in pesticide sorption during a field injection experiment

Emiel Kruisdijk; Frederik Zietzschmann; Pieter J Stuyfzand; Boris M van Breukelen

doi:10.1016/j.jconhyd.2022.104015

Intra aquifer variations in pesticide sorption during a field injection experiment

J Contam Hydrol. 2022 Jun:248:104015. doi: 10.1016/j.jconhyd.2022.104015. Epub 2022 Apr 26.

Authors

Emiel Kruisdijk¹, Frederik Zietzschmann², Pieter J Stuyfzand³, Boris M van Breukelen⁴

Affiliations

¹ Delft University of Technology, Faculty of Civil Engineering and Geosciences, Department of Water Management, Stevinweg 1, 2628 CN Delft, the Netherlands; Acacia Water B.V., Van Hogendorpplein 4, 2805 BM Gouda, the Netherlands. Electronic address: e.kruisdijk@tudelft.nl.
² Delft University of Technology, Faculty of Civil Engineering and Geosciences, Department of Water Management, Stevinweg 1, 2628 CN Delft, the Netherlands; Berliner Wasserbetriebe, Motardstr. 35, 13629 Berlin, Germany.
³ Delft University of Technology, Faculty of Civil Engineering and Geosciences, Department of Water Management, Stevinweg 1, 2628 CN Delft, the Netherlands; Stuyfzand Hydroconsult+, 2042 BL Zandvoort, the Netherlands.
⁴ Delft University of Technology, Faculty of Civil Engineering and Geosciences, Department of Water Management, Stevinweg 1, 2628 CN Delft, the Netherlands.

PMID: 35489141
DOI: 10.1016/j.jconhyd.2022.104015

Abstract

A field injection experiment was performed in an anoxic sandy aquifer over 6 days to assess sorption characteristics of 7 commonly applied pesticides in agriculture and 2 frequently detected metabolites. Pesticide use changed considerably in the last decades, and there is insufficient knowledge of the fate of currently used pesticides in aquifers. Injected water arrival was monitored at 6 depth intervals of 1 m ranging from 11.4 to 32.2 m-below surface level with varying organic carbon contents (0.057-0.91%d.w.) to examine intra-aquifer variations in sorption. Observed pesticide concentrations were fit using a non-linear least squares routine to an advection-dispersion equation, from which retardation factors (R) were obtained. Pesticide degradation did not significantly influence the simulated R during the experiment. We observed that bentazon and cycloxydim were most mobile with R < 1.1 at all depths. Desphenyl chloridazon, methyl desphenyl chloridazon, and imidacloprid were, on average, less mobile, with maximum R of 1.5. Boscalid, chloridazon, fluopyram, and flutolanil showed a larger range of R, and R > 2.0 were observed in the shallowest part of the aquifer. Largest R were observed at the top of the aquifer and decreased with depth. K_oc values varied similarly, which indicates that sorption is not only influenced by sedimentary organic matter (SOM) content but also by its sorption reactivity. Obtained sorption parameters were substantially lower than reported in a widely used pesticide sorption database, which suggests that sorption parameters are influenced by methodological differences and variations in the sorption reactivity of SOM. The large intra-aquifer variations in pesticide sorption highlights that aquifer heterogeneity should be considered in groundwater risk assessments.

Keywords: Aquifer storage recovery; Emerging contaminants; Field study; Managed aquifer recharge; Organic micropollutants; Retardation.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Groundwater*
Pesticides* / analysis
Water Pollutants, Chemical* / analysis

Substances

Pesticides
Water Pollutants, Chemical