Toxic Effects of Antiparasitic Pesticides Used by the Salmon Industry in the Marine Amphipod Monocorophium insidiosum

Felipe Tucca,Jeannette Silva,Enrique Bay-Schmith,Ricardo Barra,Gabriel Cruz,Gustavo Chiang,Mauricio Díaz-Jaramillo

doi:10.1007/s00244-014-0008-8

Abstract

The use of antiparasitic pesticides (APs) has been widely required by the salmon industry to treat diseases. The direct emission of chemicals in the seawater has produced uncertainty about the potential effects on nontarget organisms, such as crustaceans. The aim of this study was to assess the toxicity of three APs used by the salmon farm industry, such as emamectin benzoate (EB), cypermethrin (CP), and deltamethrin (DE), in the amphipod Monocorophium insidiosum during 10 days through whole-sediment bioassay tests. Lethal concentration by 50 % (LC50–10d) and biochemical responses, such as glutathione S-transferase (GST) and thiobarbituric acid reactive substances (TBARS), were measured as exposure and effects end points, respectively. Acute assays for DE (7.8 μg kg−1, confidence interval, CI95% 5–11) and CP (57 μg kg−1, CI95% 41–77) showed more mortality than EB (890 μg kg−1, CI95% 672–1,171). In this study, it was possible to observe sublethal responses in amphipods after 2 days of exposure to APs. Significant induction in GST and TBARS (p < 0.05) were measured for CP and EB. Lower DE concentrations showed no significant biochemical responses. M. insidiosum was sensitive to AP concentrations at μg kg−1 in sediments. This information would allow considering the possible consequences of detected concentrations for APs in areas with intensive salmon farming activity.

Highlights

The use of antiparasitic pesticides (APs) has been widely required by the salmon industry to treat diseases
AP testing showed that emamectin benzoate (EB) had the highest LC50 at a concentration of 890 lg kg-1 (95 % confidence interval (CI95%) = 672–1,171) contrary to what happened with CP and DE pyrethroid compounds, in which there was a greater lethality in tested amphipods
Toxicity data for EB organic compound (LC50 = 890 lg kg-1) obtained in this study suggests an LC50 greater than that reported in the literature for other marine amphipods

Summary

Introduction

The use of antiparasitic pesticides (APs) has been widely required by the salmon industry to treat diseases. Management, and control of parasites, the industry has required a wide range of antiparasitic pesticides (APs), such as chemotherapeutic treatments Pesticides, such as emamectin benzoate (EB), avermectin and synthetic pyrethroids, cypermethrin (CP), and deltamethrin (DE), have been used to combat parasitic diseases (Burridge et al 2010). These amphipods inhabit primarily estuarine and brackish waters from infralittoral zones with a basic supply of suspended particles, microfauna, diatoms, phytoplankton, and zooplankton (Macdonald et al 2010) Ecotoxicological tests with these amphipods have shown effective results in tests with contaminated sediments and low-sensitivity external factors, so their responses have been considered as a good toxicity indicator (Prato and Biandolino 2006)

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Conclusion