title: Synergistic toxic effects of zinc pyrithione and copper to three marine species: Implications on setting appropriate water quality criteria.
abstract: Zinc pyrithione (ZnPT) is widely applied in conjunction with copper (Cu) in antifouling paints as a substitute for tributyltin. The combined effects of ZnPT and Cu on marine organisms, however, have not been fully investigated. This study examined the toxicities of ZnPT alone and in combination with Cu to the diatom Thalassiosira pseudonana, polychaete larvae Hydroides elegans and amphipod Elasmopus rapax. Importantly, ZnPT and Cu resulted in a strong synergistic effect with isobologram interaction parameter lambda>1 for all test species. The combined toxicity of ZnPT and Cu was successfully modelled using the non-parametric response surface and its contour. Such synergistic effects may be partly due to the formation of copper pyrithione. It is, therefore, inadequate to assess the ecological risk of ZnPT to marine organisms solely based on the toxicity data generated from the biocide alone. To better protect precious marine resources, it is advocated to develop appropriate water quality criteria for ZnPT with the consideration of its compelling synergistic effects with Cu at environmentally realistic concentrations.
authors.affiliation: The Swire Institute of Marine Science, Division of Ecology and Biodiversity, School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China. weiwei.bao@gmail.com
authors.forename: Vivien W W
authors.initials: VW
authors.lastname: Bao
authors.forename: Kenneth M Y
authors.initials: KM
authors.lastname: Leung
authors.forename: Kevin W H
authors.initials: KW
authors.lastname: Kwok
authors.forename: Amy Q
authors.initials: AQ
authors.lastname: Zhang
authors.forename: Gilbert C S
authors.initials: GC
authors.lastname: Lui
mesh_terms: D033304:Amphipoda / Q000187:drug effects*; D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects; D003300:Copper / Q000633:toxicity*; D017377:Diatoms / Q000187:drug effects*; D004357:Drug Synergism; D007928:Lethal Dose 50; D008386:Marine Biology; D009942:Organometallic Compounds / Q000633:toxicity*; D011077:Polychaeta / Q000187:drug effects*; D011725:Pyridines / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000592:standards* / Q000633:toxicity*
chemical_list: D009942:Organometallic Compounds; D011725:Pyridines; D014874:Water Pollutants, Chemical; D003300:Copper; C010423:pyrithione zinc