Accession Number : ADA322639
Title : Effects of Contaminants on Naiad Mollusks (Unionidae): A Review,
Corporate Author : FISH AND WILDLIFE SERVICE WASHINGTON DC
Personal Author(s) : Havlik, Marian E. ; Marking, Leif L.
PDF Url : ADA322639
Report Date : 1987
Pagination or Media Count : 27
Abstract : Although the uptake, storage, and elimination of contaminants by naiad mollusks has been studied, relatively little information is available on toxicity. Contaminants appear to have destroyed some populations directly by exerting toxic effects, or indirectly by causing or contributing to the elimination of essential food organisms or host fish. The most frequently studied contaminants are Cd, Cu, Mn-Mn54, Pb-Pb210, and Zn-Zn65. Manganese seems to be most readily taken up and stored in tissues; no apparent damage has been reported from tissue concentrations of thousands of parts per million (ppm) and the element appears to be essential to metabolism. Zinc and cadmium also accumulate at high levels in tissues. Lead was never found to be lethal in the studies reviewed. Various common contaminants have been reported to be toxic at the following concentrations (ppm): cadmium, 2; copper sulfate, 2 to 18.7; ammonia, 5; potassium, 11; chromium, 12.4; arsenic trioxide, 16; copper, 19; and zinc, 66. In long-term exposures, concentrations of copper as low as 25 parts per billion (ppb) were lethal. Fry of fish infected with 20-35 glochidia were more sensitive than uninfected fish to toluene, naphthalene, and crude oil. Although few specific adverse impacts of contaminants have become clearly evident, circumstantial evidence leaves little doubt that contaminants have been responsible for decreases in population density, range, and diversity. Stresses that have been responsible for the disappearance of naiad mollusks in contaminated areas have not generally been identified, and the components of the stresses have seldom been quantitatively and qualitatively correlated with the composition and size of the naiad fauna. Often two or more factors appear to work in combination to produce the total stress that adversely affects populations.
Descriptors : *TOXICITY, *FOOD, *FISHES, *MICROORGANISMS, *TOXIC DISEASES, *MOLLUSCA, STRESSES, DAMAGE, METABOLISM, AMMONIA, OXIDES, COPPER COMPOUNDS, CONCENTRATION(COMPOSITION), CONTAMINANTS, ZINC, CADMIUM, ANIMALS, CHROMIUM, STORAGE, SULFATES, CONTAMINATION, ARSENIC, POTASSIUM, MANGANESE, CRUDE OIL, TOLUENES, NAPHTHALENES.
Subject Categories : Biology
Solid Wastes Pollution and Control
Water Pollution and Control
Distribution Statement : APPROVED FOR PUBLIC RELEASE