Article

Environmental concentrations of agricultural-use pesticide mixtures evoke primary and secondary stress responses in rainbow trout

Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.
Environmental Toxicology and Chemistry (Impact Factor: 3.23). 11/2011; 30(11):2602-7. DOI: 10.1002/etc.656
Source: PubMed

ABSTRACT

The present study sought to determine whether environmentally realistic mixtures of agriculturally important pesticides are stressful to fish. Juvenile rainbow trout were exposed for 96 h to concentrations of a pesticide mixture found in a waterway that is the focus of salmon restoration efforts (Nicomekl River, BC, Canada). This mixture contained organochlorine, organophosphorus, phenylurea, and triazine classes of pesticides. Fish given a realistic mixture exposure (total concentration, 1.01 µg/L) had increased plasma cortisol concentration, packed red cell volume, hematocrit (Hct), as well as decreased white cell volume, leukocrit (Lct). Similar changes in Hct and Lct were apparent after exposure to a lower concentration (0.186 µg/L). Interestingly, no changes in plasma cortisol concentration, Hct, or Lct were noted after exposure to a higher concentration (13.9 µg/L). This suggests that the exposure likely impaired the mechanisms enabling the stress response. Across all exposures, plasma glucose concentration was related to plasma cortisol concentration, not to pesticide mixture concentration. This suggests that a secondary stress response may be more related to variability in individual primary stress response than to differences in pesticide exposure concentrations. In summary, the present study indicates that salmon living in agrichemical-contaminated waterways may be experiencing stress, and this may pose a threat to their survival.

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    • "Numerous ecotoxicity studies using earthworms have been carried out in recent years, but they were mostly focused on effects of single pesticides (Spurgeon et al., 2002). However, in natural environments pesticides are rarely found as single compounds, but instead are often found as mixtures (Gilliom, 2007; Tierney et al., 2011). It is known that a mixture of pesticides could lead to changes in toxicity, consequently the results from a single-pesticide experiments do not reflect field situations where multiple pesticides or pesticide mixtures are used. "

    Full-text · Dataset · Jun 2014
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    • "Numerous ecotoxicity studies using earthworms have been carried out in recent years, but they were mostly focused on effects of single pesticides (Spurgeon et al., 2002). However, in natural environments pesticides are rarely found as single compounds, but instead are often found as mixtures (Gilliom, 2007; Tierney et al., 2011). It is known that a mixture of pesticides could lead to changes in toxicity, consequently the results from a single-pesticide experiments do not reflect field situations where multiple pesticides or pesticide mixtures are used. "
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    ABSTRACT: Laboratory tests were conducted in order to investigate the effects of individual and binary-combined commercial insecticides endosulfan, temephos, malathion and pirimiphos-methyl on the earthworm Eisenia andrei. The effects of individual insecticides were determined by measuring the activities of acetylcholinesterase (AChE), catalase (CAT) and glutathione-S-transferase (GST). After exposure to studied insecticides, dose-dependent decrease in AChE activity and dose-dependent increase in CAT activity was recorded. The activity of GST was without consistent dose-response reaction, but generally the investigated insecticides caused the increase in GST activity. In order to determine the effects of binary-combined mixtures, and interactions between the components in the mixture, the relationship between effective concentration of AChE inhibition for mixture and effective concentration of AChE inhibition for each component in the mixture was investigated. The obtained results showed additive effect for mixtures endosulfan+malathion; endosulfan+pirimiphos-methyl; temephos+malathion and temephos+pirimiphos-methyl, synergistic effect for mixture endosulfan+temephos and in the case of mixture malathion+pirimiphos-methyl the antagonistic effect was indicated.
    Full-text · Article · Jul 2013

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