title: Metal-Polycyclic Aromatic Hydrocarbon Mixture Toxicity in Hyalella azteca. 1. Response Surfaces and Isoboles To Measure Non-additive Mixture Toxicity and Ecological Risk.
abstract: Mixtures of metals and polycyclic aromatic hydrocarbons (PAHs) occur ubiquitously in aquatic environments, yet relatively little is known regarding their potential to produce non-additive toxicity (i.e., antagonism or potentiation). A review of the lethality of metal-PAH mixtures in aquatic biota revealed that more-than-additive lethality is as common as strictly additive effects. Approaches to ecological risk assessment do not consider non-additive toxicity of metal-PAH mixtures. Forty-eight-hour water-only binary mixture toxicity experiments were conducted to determine the additive toxic nature of mixtures of Cu, Cd, V, or Ni with phenanthrene (PHE) or phenanthrenequinone (PHQ) using the aquatic amphipod Hyalella azteca. In cases where more-than-additive toxicity was observed, we calculated the possible mortality rates at Canada's environmental water quality guideline concentrations. We used a three-dimensional response surface isobole model-based approach to compare the observed co-toxicity in juvenile amphipods to predicted outcomes based on concentration addition or effects addition mixtures models. More-than-additive lethality was observed for all Cu-PHE, Cu-PHQ, and several Cd-PHE, Cd-PHQ, and Ni-PHE mixtures. Our analysis predicts Cu-PHE, Cu-PHQ, Cd-PHE, and Cd-PHQ mixtures at the Canadian Water Quality Guideline concentrations would produce 7.5%, 3.7%, 4.4% and 1.4% mortality, respectively.
authors: Faculty of Natural Resources Management, Lakehead University , Thunder Bay, Ontario, Canada P7B 5E1.
authors: Patrick T
authors: PT
authors: Gauthier
authors: Aquatic Contaminants Research Division, Environment Canada , Burlington, Ontario, Canada L7S 1A1.
authors: Warren P
authors: WP
authors: Norwood
authors: Faculty of Natural Resources Management, Lakehead University , Thunder Bay, Ontario, Canada P7B 5E1.
authors: Ellie E
authors: EE
authors: Prepas
authors: Department of Biological Sciences, University of Lethbridge , Lethbridge, Alberta, Canada T1K 3M4.
authors: Greg G
authors: GG
authors: Pyle
mesh_terms: D033304:Amphipoda / Q000187:drug effects*; D000818:Animals; D058448:Biota; D002170:Canada; D055669:Ecological and Environmental Phenomena; D008670:Metals / Q000633:toxicity*; D011084:Polycyclic Aromatic Hydrocarbons / Q000633:toxicity*; D012307:Risk Factors; D018675:Toxicity Tests
chemical_list: D008670:Metals; D011084:Polycyclic Aromatic Hydrocarbons