title: Site-specific water quality criteria for lethal/sublethal protection of freshwater fish exposed to zinc in southern Taiwan.
abstract: There were considerable concerns about the zinc (Zn) pollution caused by electroplating, chemical, and computer-related high-tech industrial discharges in Kaohsiung Rivers situated at south Taiwan. There is, however, a lack of site-specific water chemistry based toxicity assessment and little is known about the sublethal toxicity on freshwater fish. This study proposes an integrated framework to link experimental and mechanistic model-based data analysis of lethal and sublethal Zn toxicities for grass carp (Ctenopharyn odon idellus) populations for providing the site-specific Zn water quality threshold in Kaohsiung Rivers. A biotic ligand model (BLM) that relates toxicity impairment of physiological active sites impacted by Zn species was used to elucidate the site-specific water chemistry affecting the bioavailability and biological response of grass carp exposed to Zn. Results indicated that 96-h LC50 for mortality and 28-d EC50 for growth inhibition were 474.7 ± 1.3 (mean ± SE) and 149 ± 23.5 μg L(-1), respectively. Here the BLM-based predicted steady-state LC50s for mortality were 2110.7, 818.2, 1303.6, 563.3, and 497.1 μg L(-1), whereas measured steady-state EC50s for growth inhibition were 726.8, 326.2, 373.4, 193.9, and 170.5 μg L(-1) for the Agongdian, Houling, Love, Fengshan, and Gaoping Rivers, respectively. A positive correlation between Mg(2+) and EC50 values were found in both acute (r = 0.94, p < 0.01) and chronic (r = 0.97, p < 0.01) Zn exposures. This study suggests that the use of site-specific water chemistry data and ecophysiological traits would enhance the predictive capacities to assess the potential effect of metal toxicity posed to aquatic organisms.
authors.affiliation: Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung 80708, Taiwan, ROC. Electronic address: f9662016@ntu.edu.tw.
authors.forename: Wei-Yu
authors.initials: WY
authors.lastname: Chen
authors.affiliation: Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung 80708, Taiwan, ROC.
authors.forename: Tzu-Yin
authors.initials: TY
authors.lastname: Chen
authors.affiliation: Institute of Labor, Occupational Safety and Health, Ministry of Labor, New Taipei City 22143, Taiwan, ROC.
authors.forename: Nan-Hung
authors.initials: NH
authors.lastname: Hsieh
authors.affiliation: Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung 80708, Taiwan, ROC.
authors.forename: Yi-Ting
authors.initials: YT
authors.lastname: Ju
mesh_terms: D000818:Animals; D002347:Carps / Q000254:growth & development*; D007928:Lethal Dose 50; D008962:Models, Theoretical; D045483:Rivers / Q000737:chemistry*; D013624:Taiwan; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity*; D060753:Water Quality; D015032:Zinc / Q000032:analysis / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical; D015032:Zinc
keywords: Biotic ligand model; Ecotoxicology; Freshwater fish; Site-specific water quality; Zinc