title: Ecotoxicity of binary mixtures of Microcystis aeruginosa and insecticides to Daphnia pulex.
abstract: In aquatic ecosystems, mixtures of chemical and natural stressors can occur which may significantly complicate risk assessment approaches. Here, we show that effects of binary combinations of four different insecticides and Microcystis aeruginosa, a toxic cyanobacteria, on Daphnia pulex exhibited distinct interaction patterns. Combinations with chlorpyrifos and tetradifon caused non-interactive effects, tebufenpyrad caused an antagonistic interaction and fenoyxcarb yielded patterns that depended on the reference model used (i.e. synergistic with independent action, additive with concentration addition). Our results demonstrate that interactive effects cannot be generalised across different insecticides, not even for those targeting the same biological pathway (i.e. tebufenpyrad and tetradifon both target oxidative phosphorylation). Also, the concentration addition reference model provided conservative predictions of effects in all investigated combinations for risk assessment. These predictions could, in absence of a full mechanistic understanding, provide a meaningful solution for managing water quality in systems impacted by both insecticides and cyanobacterial blooms.
authors.affiliation: Laboratory of Environmental Toxicology and Aquatic Ecology, Ghent University, J. Plateaustraat 22, B-9000 Gent, Belgium. Electronic address: jana.asselman@ugent.be.
authors.forename: J
authors.initials: J
authors.lastname: Asselman
authors.affiliation: Laboratory of Environmental Toxicology and Aquatic Ecology, Ghent University, J. Plateaustraat 22, B-9000 Gent, Belgium.
authors.forename: C R
authors.initials: CR
authors.lastname: Janssen
authors.affiliation: Laboratory of Agrozoology, Ghent University, Belgium.
authors.forename: G
authors.initials: G
authors.lastname: Smagghe
authors.affiliation: Laboratory of Environmental Toxicology and Aquatic Ecology, Ghent University, J. Plateaustraat 22, B-9000 Gent, Belgium.
authors.forename: K A C
authors.initials: KA
authors.lastname: De Schamphelaere
mesh_terms: D000818:Animals; D004390:Chlorpyrifos / Q000633:toxicity*; D003621:Daphnia / Q000187:drug effects; D007306:Insecticides / Q000633:toxicity*; D052998:Microcystins / Q000633:toxicity*; D046931:Microcystis / Q000254:growth & development*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D007306:Insecticides; D052998:Microcystins; D014874:Water Pollutants, Chemical; D004390:Chlorpyrifos
keywords: Daphnia; Insecticides; Microcystis aeruginosa; Mixture toxicity