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United States Department of Agriculture

Agricultural Research Service

Title: Fish Tissue Contamination in Regions of the Yalobusha River and Grenada Reservoir Watershed

Authors
item Cooper, Charles
item Testa, Sam
item Knight, Scott
item Welch, Terry

Submitted to: Mississippi Water Resources Research Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: August 27, 2003
Publication Date: October 8, 2003
Citation: Cooper, C.M., Testa III, S., Knight, S.S., Welch, T.D. 2003. Fish Tissue Contamination in Regions of the Yalobusha River and Grenada Reservoir Watershed. Mississippi Water Resources Research Conference Proceedings. Mississippi Water Resources Research - Geo Resources Institute, Mississippi State University, pp. 57-67. CD-ROM.

Interpretive Summary: The Yalobusha River watershed is currently receiving major modifications designed to remedy widespread channel instability and flooding in the Calhoun City region caused by a large debris jam that has occluded the river channel in that area. Another possible benefit may be a reduction in fish contamination by decreased contaminant inputs. This is important to many resident and non-resident citizens, as the river and its downstream recipient, Grenada Reservoir, are frequently used by recreational and subsistence fishermen. We analyzed available data on metals, persistent pesticides, and PCB concentrations from over 400 fish taken from the Yalobusha River Watershed. DDT and metabolites (summed) were observed in highest average concentrations in fish tissues from the Yalobusha River upstream of the debris jam (327 ppb), in the new channel bypassing the debris jam (251 ppb), the river downstream of the debris jam (243 ppb) and in the spillway channel below the reservoir (224 ppb). Lowest average DDT concentrations were observed from fish in tributaries, either upstream (14 ppb) or downstream (5 ppb) of the debris jam, and in the main body of Grenada Reservoir (20 ppb). Of all fish sampled during our study of Grenada Reservoir, only one large Largemouth Bass (460 mm length, weight 1.53 kg) had a flesh concentration of mercury above the USFDA action level of 1 ppm, and that single fish was only slightly (1.032 ppm) above the level. PCBs were never detected in fish from Grenada Reservoir or watershed tributaries, and were only rarely detected from fish of the Yalobusha River. The persistent pesticide toxaphene was detected in only one fish at low levels, and chlordane, the third most common cause of advisories in the U.S., was never detected in fish during our study.

Technical Abstract: The Yalobusha River and its recipient, Grenada Reservoir, are frequently used by recreational and subsistence fishermen. The watershed is currently receiving major modifications designed to remedy widespread channel instability and flooding in the Calhoun City, MS, region caused by a large debris jam that has occluded the river channel. These remedial actions should decrease future fisheries contamination by decreasing contaminant inputs. To provide a base line of current contaminant concentrations in the system, we analyzed available data on metals, persistent pesticides, and PCB concentrations from 462 fish. Highest average arsenic (11.8 ppm), copper (2.26 ppm), and lead (0.318 ppm) tissue concentrations (viscera, flesh, and whole fish) were observed in the river downstream of the debris jam, while highest average concentrations of iron (137 ppm), chromium (0.308 ppm), cadmium (0.163 ppm) and zinc (18.46 ppm) occurred in Grenada Reservoir. Mercury was observed in similar concentration in fish from most watershed divisions (average 0.269 ppm) but was much lower in the Yalobusha River (0.065 ppm). DDT and metabolites (summed) were observed in highest average concentrations in fish tissues from the Yalobusha River upstream of the debris jam (327 ppb). Lowest average DDT concentrations were observed from fish in tributaries, either upstream (14 ppb) or downstream (5 ppb) of the debris jam, and in the main body of Grenada Reservoir (20 ppb). PCBs were never detected in fish from Grenada Reservoir or watershed tributaries, and were only rarely detected from fish of the Yalobusha River. Chlordane, the third most common cause for advisories in the U.S., was never detected in fish during our study.

Last Modified: 12/20/2014
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