New Approach to the Determination of Bioavailable Metals in Surface Waters

摘要

The goal of this research was to develop analytical methods capable ofdetermining the concentration of toxic (bioavailable) forms of copper in natural surface waters. The approach should also be applicable to other metals. The approach was: (1) to determine the apparent binding affinity of the gills of fish and other aquatic biota for copper using novel competition bioassay and copper residue accumulation techniques; and (2) to modify the performance of commercial cation exchange resins or synthesize custom-made cation exchange resins, to match the copper binding affinity of fish and other aquatic biota. Using a range of procedures, the apparent copper binding affinities (log of the Apparent Binding Affinity (ABA)) were determined for rainbow trout gills (6.4-7.2), brook trout gills (7.1-7.2), trout mucus (6.97.7), and Daphnia magna (6.6-8.1). Based on these results an acceptable value for log ABA would be 7.6 for cation-exchange chromatography procedures to measure the bioavailable fraction of copper. Commercially available resins under a variety of conditions consistently had copper binding affinities that were 2 to 3 orders of magnitude higher than the measured values for aquatic biota. Custom cation exchange resins were synthesized and yielded binding affinities closer to that of aquatic biota, but additional work is needed to standardize and validate this approach. Bioavailability, Metals, Water quality, Copper, Aquatic biota, Toxicity, Fish.