Residues of currently used pesticides in soils and earthworms: A silent threat?

https://doi.org/10.1016/j.agee.2020.107167Get rights and content

Highlights

  • Thirty-one pesticide residues were analyzed in 180 agricultural topsoils and 155 earthworms.

  • The soils (100 %) and earthworms (92 %) contained at least one pesticide.

  • Both treated fields and nontreated seminatural habitats were contaminated.

  • A greater number and higher concentrations of pesticides were found in treated areas.

  • The initial predicted environmental concentrations in soils were exceeded in 22 % of the soils.

  • A high risk of pesticide mixtures to earthworms was predicted in 46 % of cases.

Abstract

Critical knowledge gaps about environmental fate and unintentional effects of currently used pesticides (CUPs) hamper the understanding and mitigation of their global impacts on ecological processes. We investigated the exposure of earthworms to 31 multiclass CUPs in an arable landscape in France. We highlighted the presence of at least one pesticide in all soils (n = 180) and 92 % of earthworms (n = 155) both in treated crops and nontreated habitats (hedgerows, grasslands, and cereals under organic farming). Mixtures of at least one insecticide, one herbicide, and one fungicide (> limit of quantification) contaminated 90 % of soils and 54 % of earthworms at levels that could endanger these nontarget beneficial soil organisms. A high risk of chronic toxicity to earthworms was found (46 % of samples) both in treated winter cereals and nontreated habitats considered as refuges. This may alter biodiversity, hinder recovery, and impair ecosystem functions. These results provide essential insights for sustainable agriculture and CUP regulation, and highlight the potential of pesticides as agents of global change.

Abbreviations

CUPs
currently used pesticides
LC50
lethal concentration 50 %
LOD
limits of detection
LOQ
limits of quantification
NOEC
no observed effect concentration
PECs
predicted environmental concentrations in soils
RD
recommended dose
TERearthworm
toxicity/exposure ratio for earthworms
ZA-PVS
Zone Atelier Plaine & Val de Sèvre

Keywords

Soil-Dwelling invertebrates
Agroecology
Plant protection products
Risk assessment
Nontarget wildlife

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