Storm-event-transport of urban-use pesticides to streams likely impairs invertebrate assemblages.

Kurt D Carpenter,Kathryn M Kuivila,Michelle L Hladik,Michael B Cole,Tana Haluska

doi:10.1007/s10661-016-5215-5

Kurt D Carpenter, Kathryn M Kuivila + Show 3 more

Open Access

https://doi.org/10.1007/s10661-016-5215-5

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Abstract

Insecticide use in urban areas results in the detection of these compounds in streams following stormwater runoff at concentrations likely to cause toxicity for stream invertebrates. In this 2013 study, stormwater runoff and streambed sediments were analyzed for 91 pesticides dissolved in water and 118 pesticides on sediment. Detections included 33 pesticides, including insecticides, fungicides, herbicides, degradates, and a synergist. Patterns in pesticide occurrence reveal transport of dissolved and sediment-bound pesticides, including pyrethroids, from upland areas through stormwater outfalls to receiving streams. Nearly all streams contained at least one insecticide at levels exceeding an aquatic-life benchmark, most often for bifenthrin and (or) fipronil. Multiple U.S. EPA benchmark or criterion exceedances occurred in 40 % of urban streams sampled. Bed sediment concentrations of bifenthrin were highly correlated (p < 0.001) with benthic invertebrate assemblages. Non-insects and tolerant invertebrates such as amphipods, flatworms, nematodes, and oligochaetes dominated streams with relatively high concentrations of bifenthrin in bed sediments, whereas insects, sensitive invertebrates, and mayflies were much more abundant at sites with no or low bifenthrin concentrations. The abundance of sensitive invertebrates, % EPT, and select mayfly taxa were strongly negatively correlated with organic-carbon normalized bifenthrin concentrations in streambed sediments. Our findings from western Clackamas County, Oregon (USA), expand upon previous research demonstrating the transport of pesticides from urban landscapes and linking impaired benthic invertebrate assemblages in urban streams with exposure to pyrethroid insecticides.Electronic supplementary materialThe online version of this article (doi:10.1007/s10661-016-5215-5) contains supplementary material, which is available to authorized users.

Highlights

Reductions in the abundance or diversity of aquatic insects can have important consequences for aquatic ecosystems, for young salmon and steelhead that consume aquatic invertebrates (National Marine Fisheries Service 2012), and birds and bats that feed on the adult insects that hatch from streams (Baxter et al 2005)
Pesticides were detected at all sites in one or more sample types/phases, with up to 12 pesticides detected per site
Twenty samples of stormwater runoff from outfalls and streams resulted in the detection of 18 pesticides, mostly fungicides and insecticides (Tables 2 and 3)

Summary

Introduction

Reductions in the abundance or diversity of aquatic insects can have important consequences for aquatic ecosystems, for young salmon and steelhead that consume aquatic invertebrates (National Marine Fisheries Service 2012), and birds and bats that feed on the adult insects that hatch from streams (Baxter et al 2005). Frequent detection of insecticides at high concentrations in urban streams nationally (Stone et al 2014) suggests that exposure to these compounds is another stressor likely to impact aquatic invertebrates. New types of insecticides have increased in use, pyrethroids (bifenthrin in particular), and fipronil, a phenyl pyrazole insecticide. Residues of these insecticides are showing up in some of California’s urban streams at levels of concern (Weston et al 2014; Ensminger et al 2013)

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