Editors: JS Meyer, SJ Clearwater, TA Doser, MJ Rogaczewski, JA Hansen
For decades, researchers have demonstrated that the toxicity of cationic metals (e.g., Cd, Cu, Ni, Pb, Zn) to aquatic organisms is affected by a variety of water chemistry parameters, including pH, alkalinity, hardness, dissolved organic matter, and suspended solids. Yet until recently, only water hardness was explicitly incorporated as a toxicity-modifying factor in the regulation of cationic-metal discharges. However, rapid advances in several areas of aquatic chemistry and toxicology during the past decade have opened the possibility of incorporating into regulatory decisions a mechanistic understanding of the availability and toxicity of metals to aquatic organisms. Specifically, advances in the ability to model interactions between metals and dissolved organic matter; to model interactions of metals at the surface of or in organisms; and to relate accumulation of metals at biological surfaces to toxicity, are being used to develop a "next-generation approach” to establishing acceptable metal concentrations.
This book reviews the history of the regulation of cationic-metal discharges, the variety of water quality conditions into which metals can be discharged, the different types of geochemical speciation models that are used to predict cationic-metal availability over a range of water quality conditions, and the large amount of research related to the effects of water chemistry on the physiology and toxicity of cationic metals to aquatic organisms. The authors argue that biotic ligand models should be incorporated into the regulation of discharges of cationic metals, and they suggest additional research needed to support and advance this approach. This book is a unique and valuable resource for members of academia, government, and business who conduct research on or are involved in the regulation of cationic metals.