title: Using field data to assess the effects of pesticides on crustacea in freshwater aquatic ecosystems and verifying the level of protection provided by water quality guidelines.
abstract: The purpose of this study was to investigate how well single-species laboratory data predict real-world pesticide toxicity effects on Crustacea. Data from field pesticide exposures from experimental mesocosm and small pond studies were converted into toxicity units (TUs) by dividing measured pesticide concentrations by the L(E)C50 for Daphnia or acute 5% hazard concentration for Crustacea (HC5-C). The proportion of crustacean taxa significantly affected by the pesticide treatment, called the count ratio of effect, was used in logistic regression models. Of 200 possible logistic model combinations of the TUs, fate, physicochemical variables, and structural variables versus the count ratio of effect for the mesocosm data, the best model was found to incorporate log(TU HC5-C). This model was used to convert pesticide water quality guidelines from around the world into estimates of the proportion of crustacean taxa predicted to be impacted by exposure to a pesticide at the water quality guideline concentration. This analysis suggests 64% of long-term water quality guidelines and 88% of short-term pesticide water quality guidelines are not protective of the aquatic life they are designed to protect. We conclude that empirically derived data from mesocosm studies should be incorporated into water quality guideline derivation for pesticides where available. Also, interspecific differences in susceptibility should be accounted for more accurately to ensure water quality guidelines are adequately protective against the adverse effects of pesticide exposure.
authors.affiliation: Strategic Policy Branch, Environment Canada, 4th Floor, Les Terrasses de la Chaudière, 10 Wellington Street, Gatineau, Quebec K1A 0H3, Canada. martha.guy@ec.gc.ca
authors.forename: Martha
authors.initials: M
authors.lastname: Guy
authors.forename: Lucina
authors.initials: L
authors.lastname: Singh
authors.forename: Pierre
authors.initials: P
authors.lastname: Mineau
mesh_terms: D000818:Animals; D003247:Conservation of Natural Resources / Q000379:methods*; D003445:Crustacea / Q000187:drug effects*; D017753:Ecosystem; D054750:Ecotoxicology / Q000379:methods*; D005618:Fresh Water; D017408:Guidelines as Topic; D007753:Laboratories; D010573:Pesticide Residues / Q000633:toxicity*; D011786:Quality Control; D013997:Time Factors
chemical_list: D010573:Pesticide Residues