Author
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Griffin, Billy |
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SCHLENK, DANIEL - UNIV OF MISSISSIPPI |
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Submitted to: U.S. FDA Public Master File No. 5590
Publication Type: Popular Publication Publication Acceptance Date: 7/28/1997 Publication Date: N/A Citation: N/A Interpretive Summary: The amount of copper introduced into the environment as a result of use of copper sulfate to control fish diseases is miniscule compared to other sources. Due to it chemical nature, spread in the air is limited and transport in surface waters is restricted to near its source. This is because copper is rapidly removed from water and is, for all practical purposes, irreversibly bound in the sediments that fall from the water to the bottom. Aquatic and land plants have developed high tolerances to environmental copper and animals have developed ways to limit the uptake of copper of to rapidly eliminate copper once it is absorbed. The possibility of environmental contamination resulting from its use as a fish disease treatment is small. Technical Abstract: Cupric sulfate pentahydrate (copper sulfate) has been used for decades for the treatment of fish diseases caused by aquatic parasites, bacteria and fungi. The biocidal effects of copper delivered by treatment of water with copper sulfate are acute effects and not chronic effects. The Cu++ ion is regarded as the ion species most responsible for copper's biocidal effect. Copper, as the free Cu++ ion, added to fish culture water is quickly adsorbed by soil particles, by organic ligands, or other inorganic or organic ligands and is absorbed by planktonic species. Toxicity of copper decreases with increasing water hardness and alkalinity. Copper in sediments of fish culture ponds is, for all practical purposes, irreversibly bound. Flux of elemental copper from aquatic sediments is extremely slow and is essentially non-existent in the range of pH values commonly found in fish culture. Transport of copper from fish culture ponds by way of discharge of copper-carrying water can occur only if pond water is discharged within hours after use of copper sulfate as a disease treatment. Such a discharge would defy common practices and physical possibilities in fish production. Introduction of copper from copper sulfate treated fish culture ponds can occur only if sediments are discharged during draw down for repair or if sediments are dredged and applied to terrestrial areas. Rooted and non-rooted aquatic plants have high copper tolerances and many have developed mechanisms to limit copper |
