Long-term relationships among pesticide applications, mobility, and soil erosion in a vineyard watershed

Pierre Sabatier; Jérôme Poulenard; Bernard Fanget; Jean-Louis Reyss; Anne-Lise Develle; Bruno Wilhelm; Estelle Ployon; Cécile Pignol; Emmanuel Naffrechoux; Jean-Marcel Dorioz; Bernard Montuelle; Fabien Arnaud

doi:10.1073/pnas.1411512111

New Research In

Edited by Jules M. Blais, University of Ottawa, Ottawa, Canada, and accepted by the Editorial Board September 15, 2014 (received for review June 19, 2014)

Significance

A record of lake sediment spanning approximately 100 years allowed us to reconstruct the long-term succession of herbicide, fungicide, and insecticide treatments in a vineyard catchment in France. This record of pesticide deposition is consistent with the historical onset and banning of these chemical substances by French and European environmental agencies. We also present evidence of the effects of postemergence herbicides, such as glyphosate, on soil erosion and evidence of the release of banned remnant pesticides, such as dichlorodiphenyltrichloroethane (DDT), that are stored in vineyard soil back into the environment. These results indicate that the sink–source dynamics of pesticides, which are crucial in ecotoxicological risk assessment, should take into account the effects of a changing environment on pesticide storage.

Abstract

Agricultural pesticide use has increased worldwide during the last several decades, but the long-term fate, storage, and transfer dynamics of pesticides in a changing environment are poorly understood. Many pesticides have been progressively banned, but in numerous cases, these molecules are stable and may persist in soils, sediments, and ice. Many studies have addressed the question of their possible remobilization as a result of global change. In this article, we present a retro-observation approach based on lake sediment records to monitor micropollutants and to evaluate the long-term succession and diffuse transfer of herbicides, fungicides, and insecticide treatments in a vineyard catchment in France. The sediment allows for a reliable reconstruction of past pesticide use through time, validated by the historical introduction, use, and banning of these organic and inorganic pesticides in local vineyards. Our results also revealed how changes in these practices affect storage conditions and, consequently, the pesticides' transfer dynamics. For example, the use of postemergence herbicides (glyphosate), which induce an increase in soil erosion, led to a release of a banned remnant pesticide (dichlorodiphenyltrichloroethane, DDT), which had been previously stored in vineyard soil, back into the environment. Management strategies of ecotoxicological risk would be well served by recognition of the diversity of compounds stored in various environmental sinks, such as agriculture soil, and their capability to become sources when environmental conditions change.

Footnotes

↵¹To whom correspondence should be addressed. Email: pierre.sabatier{at}univ-savoie.fr.

Author contributions: P.S., J.P., B.F., and F.A. designed research; P.S., J.P., B.F., J.-L.R., A.-L.D., B.W., E.P., and C.P. performed research; P.S., B.F., C.P., J.-M.D., and F.A. contributed new reagents/analytic tools; P.S., J.P., B.F., J.-L.R., and A.-L.D. analyzed data; and P.S., J.P., E.N., J.-M.D., and B.M. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission. J.M.B. is a guest editor invited by the Editorial Board.
The data reported in this paper are deposited on PANGEA (dx.doi.org/10.1594/PANGAEA.836160).
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1411512111/-/DCSupplemental.

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