Masters Theses

Date of Award

5-1998

Degree Type

Thesis

Degree Name

Master of Science

Major

Life Sciences

Major Professor

T. Wayne Schultz

Committee Members

A. Eric Shultze, Arthur J. Stewart

Abstract

Site-specific permit limits for copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) were determined for four outfalls at the Paducah Gaseous Diffusion Plant (PGDP) in Paducah, KY. These revised limits were derived using a procedure issued by the Kentucky Division of Water (KDOW). The KDOW's method is a cost-effective alternative to the water-effect ratio (WER) method for developing site-specific numeric criteria for metals. Both methods (KDOW' s and WER) require toxicity testing and chemical-specific analyses. With the WER method, site water is spiked with the metal of interest so that a concentration-effect curve can be evaluated. No metal-spiking is required with the KDOW method; therefore, all metals of interest may be analyzed simultaneously. This difference makes the KDOW method much less expensive than the WER method. I estimated that the analytical costs required for the KDOW method were 10-20% of those required for the WER method.

Toxicity tests with Ceriodaphnia dubia and Pimephales promelas (fathead minnow) larvae showed that the concentrations of metals in the effluents were not great enough to be toxic to the test organisms. Also, the concentrations of Cu, Ni, Pb, and Zn in the outfalls were below the permit limits and federal numeric water quality criteria. For this reason, metals in the effluents at PGDP are not likely to cause compliance-related problems. Levels of total recoverable and dissolved Cu, Ni, Pb, and Zn were measured in the effluents. These data were used to calculate the final mean ratio of dissolved metal to total recoverable metal for each effluent. Applying the equation in the KDOW method, the measured total recoverable metal concentration is adjusted downward by the portion of the metal in the effluent that is biologically relevant (dissolved metal); this value is then reported to determine compliance with numeric limits. By using the KDOW recalculation method, the total recoverable metal concentrations of Cu, Ni, Pb, and Zn in the effluents were reduced from 4.7% to 54.1%.

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