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(329) Chronic silver toxicity: water quality parameters as modifying factors. Stubblefield, William1, Hockett, J.1, Kramer, J.2, Kramer, C.2, Paquin, P.3, Gorsuch, J.3, 1 2 3 ABSTRACT- A multi-tiered research program, sponsored by the Photographic and Imaging Manufacturers Association, is currently underway to evaluate the chronic toxicity of Ag to freshwater organisms. Ag acute and chronic toxicities has been shown to be substantially affected by various water quality parameters. The goal of this effort is to quantify the magnitude of these effects. Specifically, the importance of water hardness, chloride, meta-stable sulfide, and dissolved organic carbon as modifying factors of Ag toxicity are examined. The program consists of 3 tiers, Tier 1 evaluates the fathead minnow short-term chronic toxicity test as a predictor of long-term Ag chronic effects. Tier 2 examines the effects of each of the water quality parameters on Ag chronic toxicity using the fathead 7-d study; these data will be used, in turn, to develop a predictive model of silver chronic toxicity. Tier 3 will attempt to validate the results of the Tier 2 efforts using a limited number of early life-stage toxicity tests with fathead minnows and rainbow trout, and an aquatic invertebrate. Results of Tier 1 and 2 studies will be presented and implications for chronic Ag ambient water quality criteria discussed. Key words: silver, chronic, chloride, hardness |
