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Biomedical subjects

W W Johnson

Publications and source records attributed to W W Johnson.

At least 127 records · Page 7Linked to original sources

Environmental contaminant concentrations in biota from the lower Savannah River, Georgia and South Carolina.

Planned harbor expansion and industrial developments may adversely affect the economically important aquatic resources of the lower Savannah River, including those at the Savannah National Wildlife Refuge. To establish the present level of chemical contamination in this system, we collected a total of 102 samples of nine species of fish and fiddler crabs (Uca pugilator) from eleven sites in the lower Savannah River and on the Savannah National Wildlife Refuge, and analyzed them for concentrations of organochlorine chemicals, aliphatic and aromatic petroleum hydrocarbons, and 13 elemental contaminants: aluminum, arsenic, cadmium, chromium, cobalt, copper, iron, lead, manganese, mercury, nickel, selenium, and zinc. Residues of DDT (mainly as DDE), trans-nonachlor, dieldrin, Aroclor 1260, mirex, and petroleum hydrocarbons were common in fish from the lower Savannah River, but concentrations were below those warranting environmental concern. In general, the concentrations of elemental contaminants also were low; however, arsenic, cadmium, and chromium concentrations were elevated in fish from river stations near the city of Savannah, and lead was elevated in samples from the National Wildlife Refuge. Contamination of the lower Savannah River by organic and elemental contaminants, as indicated by concentrations in fishes and fiddler crabs, did not appear to pose a hazard.

Animals↗

Residues of organochlorine insecticides, polychlorinated biphenyls, and heavy metals in biota from Apalachicola River, Florida, 1978.

Seventy-seven composite samples composed of largemouth bass ( Micropterus salmoides ), channel catfish ( Ictaluras punctatus), threadfin shad ( Dorosoma petenense ), Asiatic clam (Corbicula fluminea ), burrowing mayfly ( Hexagenia sp.), water snake ( Natrix spp.), and little green heron ( Butorides virescens ) were collected from upper and lower reaches of the Apalachicola River, Florida, in 1978 for residue analysis of organochlorine insecticides, PCBs (polychlorinated biphenyls), and metals. Compared with data from the National Pesticide Monitoring Program and criteria recommended for the protection of aquatic life, residue concentrations were moderately high in the Apalachicola River. Biota from the upper river generally had higher organic and lower metal residues than those from the lower river. Highest residues in the biota were total DDT, total PCBs, and toxaphene. Although individual mean concentrations were below 2 micrograms/g and total organic contaminant residues never exceeded 5 micrograms/g, residue concentrations of DDT, PCBs, and toxaphene (particularly from the upper river) exceeded recommended permissible levels for the protection of aquatic life. Metal residues were generally below 1 microgram/g. Exceptions were arsenic residues in threadfin shad (1.07 micrograms/g) and Asiatic clams (1.75 micrograms/g), and selenium in eggs of channel catfish (1.39 micrograms/g). The residues observed in the biota, particularly from the upper station, indicated moderate contamination of the Apalachicola River system at the time samples were collected.

Animals↗