Observations on the fish population of a lake contaminated by radioactive wastes. Bulletin of the AMNH ; v. 110, article 4

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New York : [American Museum of Natural History]
"A three-year study of the fish population of White Oak Lake, Roane County, Tennessee, was made in 1950-1953. That lake received the radioactive waste effluent, the chemical waste effluent, and the primary-treated sewage effluent from the Oak Ridge National Laboratory. Six semi-annual estimates of the size and composition of the fish population were made by the mark-and-recapture method. Immediately following the last semiannual netting study, the lake was partially drained and treated with emulsifiable rotenone. Approximately 60 percent of the fish that had been marked during the last semi-annual netting study were recovered following the treatment with rotenone. The estimated total weight of the fish population was approximately 985 pounds per acre. The data from the mark-and-recapture studies were not quantitatively sound but did provide good qualitative information on the composition of the fish population. They indicated that white crappies and redhorse were gradually disappearing from the population; these findings were corroborated by the data from the rotenone study. Age and growth data, supplemented by data on length frequencies, indicated that the fish of White Oak Lake grew more slowly and did not live so long as fish of the same species in near-by reservoirs of the Tennessee Valley Authority. Dissection of fishes provided data on the percentage composition, by weight, of the various tissues in the body. A year-round study of the food habits of the black crappie revealed that it fed primarily on larval Chaoborus and other midges and to a certain extent on copepods and cladocerans. The bluegill, on the other hand, was very omniverous and showed no such preference for certain food items. Radioassay of samples of the various tissues of the black crappie and the bluegill indicated that radiomaterials were selectively concentrated in all tissues of the body. The hard tissues selectively concentrated radiostrontium in amounts 20,000 to 30,000 times that of the water in which they lived. Some radiophosphorus was also concentrated in the hard tissues. The soft tissues selectively concentrated cesium and the rare earths. The total body burden carried by a 7-inch black crappie during the summer of 1952 was more than a microcurie, whereas that for a 6-inch bluegill was only slightly less. There were definite seasonal changes in the accumulation of radiomaterials which corresponded, to some extent, with the seasonal changes in water temperature. However, the accumulation of radiomaterials stopped when the temperature of the water reached its maximum about August 1. The rapid loss of radiomaterials during August and September indicated that both species of fish probably entered a period of summer dormancy during that time. The total radiation dose received by the fish in White Oak Lake was estimated to be at least 57 rep per year from external irradiation and was probably several times that amount from internal irradiation. As a result of this irradiation, it is believed that the fish population of White Oak Lake may have suffered deleterious effects, as manifested by the shortened life span, the slowed growth rate, and possibly the decreased fertility of the breeding stock of the redhorse"--P. 365.
p. 281-367, [1] folded leaf of plates : ill., map ; 28 cm.
Includes bibliographical references (p. 365-367).