We developed an integrated analytical procedure for organochlorine contaminants that enables quantitation of toxaphene residues as low as 0.1 gg/g in fish tissue. Preparation of the sample requires extraction of ground tissue with dichloromethane, cleanup of the extract by gel permeation chromatography, and fractionation by Florisil and silica gel chromatography. Toxaphene residues are then characterized and quantified by capillary-column gas chromatography with electron capture. An automated data system is used to select and quantitate peaks and to eliminate interference from the high-resolution chromatograms. Selected components are then confirmed by gas chromatography-negative-ion mass spectrometry (NIMS).This procedure consistently yields results within 1% of spike concentrations. Substitution of conventional packed-column gas chromatography into the procedure reduces accuracy slightly; values average 7% below spiked concentrations. We also evaluated several confirmation techniques and other methods for eliminating analytical interferences. Nitration of the toxaphene-containing fraction before gas chromatography successfully eliminated interferences from the DDT complex but not from chlordane components. This procedure also altered the composition of the toxaphene mixture. Among the gas chromatography-mass spectrometry confirmation procedures evaluated, NIMS proved superior to the more conventional electron-impact mass spectrometry because toxaphene components were far more sensitive to NIMS.
Chemical contaminants and bone development were investigated in young‐of‐year striped bass collected in spring, summer, and fall from the Nanticoke, Potomac, and Hudson rivers and Edenton National Fish Hatchery, North Carolina. Polychlorinated biphenyls (PCB) were the most prevalent organic contaminants found in striped bass; relatively lesser amounts of DDT, DDD, DDE, and chlordane were detected. Among the four locations, striped bass from the Hudson River contained the greatest amount of PCB; concentrations significantly increased with collection date in fish from the Hudson and Potomac rivers. Total organochlorine residues in striped bass from the Edenton Hatchery and the Nanticoke River were less than those from the Hudson and Potomac rivers, and the contaminants did not increase significantly with collection date. Arsenic, lead, cadmium, and selenium were the major inorganic contaminants in striped bass in the Hudson, Nanticoke, and Potomac rivers. Cadmium in fish from the Hudson River, and selenium in fish from the Potomac River, increased significantly with collection date; other such correlations were not significant. Mechanical properties of striped bass vertebrae were significantly different among the four locations in both the spring and fall collections. Vertebrae from Hudson River fish had the least strength, stiffness, and toughness, and ruptured under the lowest force. Hatchery striped bass had the strongest and least flexible vertebrae. We suggest from previous laboratory toxicity studies that contaminants such as PCB, cadmium, and lead could weaken vertebral structure, and thus affect survival of larvae and abundance of striped bass stocks.
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