Residues of toxaphene in finfish and shellfish from Terry and Dupree Creeks, Georgia, U.S.A.

Abstract

To better characterize human health risks associated with potentially contaminated seafood, 56 composite samples of edible tissue of several finfish and shellfish species were analyzed for residues of toxaphene using gas chromatography with electron capture and negative ion mass spectrometric detection (GC-ECD and GC-ECNI-MS). Toxaphene in these samples, collected in 1997 near a former toxaphene plant in Brunswick, Georgia, were previously reported as non-detectable using non-selective techniques. Estimated total toxaphene concentrations (ΣTOX) ranged from less than 0.01 to 26 μ g⁻¹ on a wet tissue basis. Smaller, bottom dwelling finfish such as croaker, mullet, and spot exhibited the highest ΣTOX (0.76–26 μg g⁻¹), larger predatory fish including seatrout contained intermediate levels (0.08–4.4 μg g⁻¹), and shellfish (blue crab and shrimp) contained the lowest levels (<0.01 to 0.27 μg g⁻¹). For a given species, samples from the site furthest from the toxaphene plant had lower ΣTOX than samples from the other 3 sites. On a congener specific basis, levels ranged from <0.0025 to 3.5 μg g⁻¹. Congener distributions were, in general, dominated by 2-exo, 3-endo, 6-exo,8,9,10-hexachlorobornane (Hx-Sed) and 2-endo,3-exo,5-endo,6-exo,8,9,10-heptachlorobornane (Hp-Sed), breakdown products of Cl₈−Cl₁₀ toxaphene homologs. Other prominent congeners confirmed by GC-ECNI-MS included Parlar numbers 26, 40/41, 42, 44, 50, 62, and 63, as well as several unidentified Cl₆−Cl₉ homologs. Minor differences in congener distribution among species and sampling locations suggested that exposure regimes and/or intrinsic biotransformation capabilities were not uniform. These results indicate that toxaphene residues were detectable in all species surveyed and at concentrations higher than estimated previously.