Evaluation of the Acute Toxicity of Lead, Zinc, and Cadmium in Missouri Ozark Groundwater


In order to establish appropriate guidelines for the Lead Industry in Missouri's New Lead Belt, the toxicity of common compounds of Pb, Zn, and Cd was evaluated using water similar to that found in Ozark rivers and streams. Acute, non-renewal toxicological tests of 96-hour or 48-hour duration were performed using fathead minnows (Pimephales promelas) or water fleas (Daphnia magna), respectively. Test organisms were subjected to varying amounts of the chloride, sulfate, sulfide, oxide, and carbonate salts of Pb, Zn, and Cd mixed in typical Ozark groundwater. Median Lethal Concentrations (LC50) were calculated using nominal vs measured metal concentrations in the following fractions: (a) `Dissolved' metal determined on aliquots of suspensions or solutions passed through a 0.45 μm membrane filter; (b) `Available' metal obtained following pH adjustment to 4.0, standing for 24 hours and filtration; (c) `Easily dissolved' metal obtained following pH adjustment to 1.8-2.0, standing for 24 hours and filtration; and (d) `Total' recoverable metal as defined by standard USEPA procedures (nitric acid digestion). Values for observed LC50 are compared and discussed, with consideration for site-specific environmental conditions, known properties of the metal compounds, and thermodynamic equilibrium data which allow useful prediction of possible chemical speciation and identification of chemical forms responsible for toxic effects.


Biological Sciences

Second Department

Civil, Architectural and Environmental Engineering

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Article - Conference proceedings

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Publication Date

01 Jan 1994

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