n ^ GEOGRAPHIC DISTRIBUTION OF MERCURY IN ASIATIC CLAMS, CORBICULA FLUMENEA, •i FROM THE NORTH FORK HOLSTON RIVER, VIRGINIA CHESAPEAKE BAY U.S. Fish and Wildlife Service JANUARY 1993 AKO UUI GEOGRAPHIC DISTRIBUTION OF MBRCORY IN ASIATIC CLAMS, CORBICPLA FLUMINEA. FROM THE NORTH FORK HOLSTON RIVER, VIRGINIA U.S. Fish and Wildlife Service Environmental Contaminants Division Virginia Field Office White Marsh, VA 23183 Prepared by: Louis D. Seivard David A. Stilwell Stephen O. Rice and Kenneth R. Seeley Under the Supervision of: Karen L. Mayne, Supervisor Virginia Field Office and John P. Wolflin, Supervisor Chesapeake Bay Field Office • 1993 flR300J50 TABLE OP CONTENTS LIST OF TABLES ............................. ii LIST OF FIGURES ............................ iii ABSTRACT ................................. iv EXECUTIVE SUMMARY ............................ v INTRODUCTION .............................. 1 MATERIALS AND METHODS .......................... 5 RESULTS AND DISCUSSION ......................... 7 CONCLUSIONS AND RECOMMENDATIONS ..................... 9 LITERATURE CITED ............................ 15 APPENDIX A LABORATORY QUALITY CONTROL INFORMATION AND ANALYTICAL METHODS .... A-l AR300I5 LIST OF TABLES PAGE Table 1. Historic and recent records of Federally listed species and candidate species in the North Fork Holston River, Virginia .......... 3 Table 2. Mercury concentrations in Asiatic clams, Corbicula fluminea, from the North Fork Holston River, Virginia, June 1990 ............. .10 Table 3. Summary statistics for methylmercury concentrations in Asiatic clams, Corbicula fluminea from the North Fork Holston River, June 1990. ......... 11 Table 4. Summary statistics for total mercury concentrations in Asiatic clams, Corbicula fluminea from the North Fork Holston River, June 1990. ......... 12 AR300152 LIST OF FIGURES Figure 1. Sampling sites for Asiatic clams, Corbicula fluminea. North Fork Holston River, June 1990 ................. Figure 2. Total mercury and methylraercury concentrations in Asiatic clams, Corbicula fluminea from the North Fork Holston River .................. 13 Figure 3. Comparisons among sites for methylmercury concentrations in the Asiatic clam, Corbicula fluminea. from the North Fork Holston River, June 1990 ......................... 14 Figure 4. Comparisons among sites for total mercury concentrations in the Asiatic clam, Corbicula fluminea from the North Fork Holston River, June 1990 ......................... 14 ^8300153 ABSTRACT Title: Geographic distribution of mercury in Asiatic clams, Corbieula fluminea, from the North Fork Holston River, Virginia Abstract: A study was conducted quantifying mercury concentrations in the Asiatic clam, Corbicula fluminea, from the North Fork Holston River, Virginia. The purpose of this study was to determine the downstream extent of mercury contamination in aquatic biota caused by a former chlor-alkali processing plant that has been designated as a Superfund Site under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA). Results of this study would be useful in determining the limits of the riverine area that should be considered for assessment and remediation of this Superfund Site under the CERCLA process. c. fluminea were collected from one upstream (reference) site and eight sites downstream of the Superfund Site. Tissue samples from these clams were analyzed for total mercury and methylmercury. Results of these analyses show statistically significant elevations of mercury in clams from all downstream sites when compared to the upstream reference site, with the furthest site downstream being 75.2 miles below the Superfund site. Since remedial investigations conducted by the Olin Corporation have only extended 23 miles'; downstream of the Superfund Site, it is recommended that future Superfund activities define the full geographic extent of mercury contamination in the Holston River system. Key words: Environmental Contamination, Mercury, Corbicula fluminea, Asiatic clam, North Fork Holston River, Virginia, Tenessee. iv AR3QOI5U EXECUTIVE SUMMARY The North Fork Holston River is located in southwest Virginia and northeast Tennessee and comprises one of the headwater systems of the Tennessee River basin. Natural salt deposits located near the river at Saltville, Virginia have been used since the late 1800s for the production of soda ash (sodium carbonate). In 1950, production of chlorine gas and sodium hydroxide by the chlor-alkali process was begun on this site. Operation of this facility continued for 21 years. During this period an estimated 2,000 tons of salt and as much as 75 pounds of mercury were lost daily as waste. The mercury was either discharged directly to the river, or was deposited on plant grounds or in settling ponds. Although soils on the original plant site have been remediated, the settling ponds continue to discharge mercury into the North Fork Holston River to this day. Mercury concentrations in fish downstream of the chlor-alkali plant exceeded the Food and Drug Administrations action level for human consumption, resulting in the 1970 enactment of a fishing ban in Virginia and Tennessee waters. In 1982, this site was included on the National Priorities List to be addressed under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) of 1980. It is now identified as the Saltville Superfund Site. As part of the CERCLA process, a Sampling and Analytical Plan was submitted and approved by the U.S. Environmental Protection Agency (EPA}~ in 1989. This document limited the study area to a downstream limit of 30 miles below the Superfund Site. The U.S. Fish and Wildlife Service is concerned that this geographic limit does not adequately consider contaminant impacts to the lower portion of the river. The purpose of this study was to: 1. To determine whether mercury contamination from the Saltville Superfund Site extends beyond the bounds of the 30 mile study reach by measuring mercury body burdens in the Asiatic clams, Corbieula fluminea. 2. To establish baseline data to compare future sampling and document trends in the river. 3. To determine if information exists to correlate Corbicula fluminea body burden data to deleterious physiological and reproductive effects in unionid mussel species. Corbicula fluminea were collected at nine sites at approximately 10 mile intervals, from a reference site 1.7 miles upstream of the Superfund Site to a location 75.2 miles downstream near the Virginia/Tennessee state border, c. fluminea tissue was analyzed for both total mercury and methyImercury. statistically significant differences in mercury levels were observed between the upstream reference and all other sites. Concentrations of total mercury at the furthest downstream site, located 75.2 miles downstream of the Saltville Superfund Site, were over 8 times higher than levels at the reference site. Mean methyImercury concentrations at the furthest downstream site were 0.679 ppm dry weight, over 6 times control levels. AR300I55 Results of this study demonstrate that elevated levels of total and methyIraercury are found in the North Fork Holston River biota at least 75.2 miles downstream of the Saltville Superfund Site. Thus, it is very likely that remedial investigations carried out by the Olin Corporation in the North Fork Holston River have not fully quantified the extent of mercury contamination there, as these studies were limited to a downstream distance from the site of only 23 miles. It is recommended that future CERCLA activities define the full geographic extent and levels of mercury contamination in the Holston River- system. vo. AR300I56 INTRODUCTION The North Fork Holston River is located in southwest Virginia and northeast Tennessee. In 1894, the Mathieson Alkali Works began production of soda ash utilizing naturally occurring salt deposits located in the Town of Saltville in Smyth County, Virginia. In 1950, the Mathieson Chemical Company facility began producing chlorine gas and sodium hydroxide by the electrolytic chlor- alkali process, which used a mercury cell as a cathode. Olin Corporation merged with Mathieson Chemical in 1954 and took over operation of the facility. The plant ceased operation in 1972 (U.S.E.P.A. 1987; Young-Morgan 1990). In the final 21 years of plant operation, about 2000 tons of salt and as much as 75 pounds of mercury were lost daily to the soils and settling ponds at the plant site, and the North Fork Holston River (Anonymous 1983; Powell 1983; Sheehan et al. 1989). This chronic contamination resulted in the extirpation of over 30 species of freshwater mussels, a ban on the consumption of fish from this river in both Virginia and Tennessee waters, and degradation of the sport fishery and aquatic ecosystem in the North Fork Holston River (Young- Morgan 1990). Growing concern over the environmental and public health effects of mercury •*" pollution in the mid-1960s led to a site investigation of the Olin Corporation facility. High levels of mercury in fish tissue and sediments in the North Fork Holston River were discovered. After this problem was discovered, Olin made process design modifications to their facility to reduce mercury discharges into the river to approximately 113 grams per day. In 1970, the Virginia State Water Control Board adopted a Total Dissolved Solids Standard of 500 (mg/1) which Olin was unable to meet. The Saltville plant was closed in 1972 partially as a result of this standard (U.S.E.P.A. 1987). In response to evidence that fish