Metal toxicity to freshwater organisms as a function of pH: A meta-analysis.
Acidification caused by climate change and seasonal fluctuation can have profound implications for chemical toxicity to freshwater organisms. The present study aims to address this challenging issue through a comprehensive meta-analysis by comparing acute median lethal or effect concentration data (LC50 or EC50) for 10 metals and metalloids for various freshwater species obtained at different pH values. Our results revealed that element toxicity generally follows three different models, including Model-I: decreasing toxicity with increasing pH, Model-II: increasing toxicity with increasing pH, and Model-III: minimal toxicity at intermediate (optimal) pH (pH(opt)) with increasing toxicity as pH increases or decreases from pH(opt). We further examined these observations by constructing pH-dependent species sensitivity distributions (SSDs). The results indicated that the 10(th) percentile hazardous concentrations (HC10s) for copper, lead, selenium and silver generally exhibited a positive linear relationship with pH, following the Model-I. The ability to accurately predict toxicity of elements to biota in natural waters as a function of pH may be limited, however, the pH-dependent SSD approach presented in this study facilitates and helps characterize the role of pH in water quality guidelines and ecological risk assessment.
The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China.
Zhen
Z
Wang
Ecotoxicology and Fish Health Program, Environmental and Fisheries Sciences Division, Northwest Fisheries Science Center, National Oceanic and Atmospheric Administration, 2725 Montlake Boulevard East, Seattle, WA 98112, USA.
James P
JP
Meador
The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China; State Key Laboratory in Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong, China. Electronic address: kmyleung@hku.hk.
Kenneth M Y
KM
Leung
D000818:Animals; D059001:Aquatic Organisms / Q000187:drug effects*; D005618:Fresh Water / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008670:Metals / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D008670:Metals; D014874:Water Pollutants, Chemical
Ecological risk assessment; Metal; Species sensitivity distributions; Water quality guidelines; pH