TY - JOUR

T1 - The legacy of pesticide pollution

T2 - an overlooked factor in current risk assessments of freshwater systems

AU - Rasmussen, Jes

AU - Wiberg-Larsen, Peter

AU - Baattrup-Pedersen, Annette

AU - Cedergreen, Nina

AU - McKnight, Ursula S.

AU - Kreuger, Jenny

AU - Jacobsen, Dean

AU - Astrup Kristensen, Esben

AU - Friberg, Nikolai

N1 - Copyright © 2015 Elsevier Ltd. All rights reserved.

PY - 2015

Y1 - 2015

N2 - We revealed a history of legacy pesticides in water and sediment samples from 19 small streams across an agricultural landscape. Dominant legacy compounds included organochlorine pesticides, such as DDT and lindane, the organophosphate chlorpyrifos and triazine herbicides such as terbutylazine and simazine which have long been banned in the EU. The highest concentrations of legacy pesticides were found in streams draining catchments with a large proportion of arable farmland suggesting that they originated from past agricultural applications. The sum of toxic units (SumTUD.magna) based on storm water samples from agriculturally impacted streams was significantly higher when legacy pesticides were included compared to when they were omitted. Legacy pesticides did not significantly change the predicted toxicity of water samples to algae or fish. However, pesticide concentrations in bed sediment and suspended sediment samples exceeded safety thresholds in 50% of the samples and the average contribution of legacy pesticides to the SumTUC.riparius was >90%. Our results suggest that legacy pesticides can be highly significant contributors to the current toxic exposure of stream biota, especially macroinvertebrate communities, and that those communities were primarily exposed to legacy pesticides via the sediment. Additionally, our results suggest that neglecting legacy pesticides in the risk assessment of pesticides in streams may severely underestimate the risk of ecological effects.

AB - We revealed a history of legacy pesticides in water and sediment samples from 19 small streams across an agricultural landscape. Dominant legacy compounds included organochlorine pesticides, such as DDT and lindane, the organophosphate chlorpyrifos and triazine herbicides such as terbutylazine and simazine which have long been banned in the EU. The highest concentrations of legacy pesticides were found in streams draining catchments with a large proportion of arable farmland suggesting that they originated from past agricultural applications. The sum of toxic units (SumTUD.magna) based on storm water samples from agriculturally impacted streams was significantly higher when legacy pesticides were included compared to when they were omitted. Legacy pesticides did not significantly change the predicted toxicity of water samples to algae or fish. However, pesticide concentrations in bed sediment and suspended sediment samples exceeded safety thresholds in 50% of the samples and the average contribution of legacy pesticides to the SumTUC.riparius was >90%. Our results suggest that legacy pesticides can be highly significant contributors to the current toxic exposure of stream biota, especially macroinvertebrate communities, and that those communities were primarily exposed to legacy pesticides via the sediment. Additionally, our results suggest that neglecting legacy pesticides in the risk assessment of pesticides in streams may severely underestimate the risk of ecological effects.

U2 - 10.1016/j.watres.2015.07.021

DO - 10.1016/j.watres.2015.07.021

M3 - Journal article

C2 - 26207877

VL - 84

SP - 25

EP - 32

JO - Water Research

JF - Water Research

SN - 0043-1354

ER -