HARPETH RIVER SEDIMENT STUDY

One of the few sites of serious environmental concern in this area of middle Tennessee is the General Battery site [subsequently operating as Metallico], which is located on the banks of the Harpeth River in College Grove, Tennessee. Serious lead contamination has been identified in the Harpeth River downstream of the facility. The U.S. Environmental Protection Agency [USEPA] conducted emergency removal actions of lead battery chips from residential sites in the College Grove area during 2000-2001. The Agency for Toxic Substances and Disease Registry [ATSDR] has also conducted a Health Consultation in the College Grove area due to concerns over lead poisoning.(1) Lead battery casings continue to be discovered in and around the Harpeth River, and the site remains a concern to both federal and state environmental agencies.

During the 2004-05 school year, we are continuing the Harpeth River study by the analysis of river sediments for lead. River sediments tend to accumulate heavy metals, which associate with particulate matter in the water column and then are deposited on the river bottom. The bioavailability of these heavy metals to surface water and benthic organisms is of concern.

Of novel interest is the use of microwave-assisted leaching techniques for the analysis of the river sediments. Traditional methods of analysis for solid environmental samples have major limitations, including lengthy digestion/extraction times [up to 8 hours for digestion and 18 hours for extraction], which make these methods difficult to implement in an academic laboratory. In recent years, the USEPA has developed and validated several microwave-assisted extraction procedures for both solid and liquid samples. (2,3) These methods are considered superior, not only in the reproducibility of the results, but also in the time required for total sample preparation [less than 1 hour]. (4,5) The methods are now commonly performed in commercial environmental, medical, and industrial analytical laboratories. We are implementing the use of this technology for the current research study.

Three students are involved in this research. One student is performing sediment biodiversity studies, by collecting, identifying, and counting benthic macroinvertebrates at the site. Another student is concentrating on the political and public policy decisions and enforcement actions that have been taken at the site. The third is focusing on the lab and field aspects of the project.

BIBLIOGRAPHY

1. ATSDR, Harpeth River Site, College Grove, Williamson County, Tennessee, CERCLIS NO. TND004048690, March 14, 2000.
2. U.S. EPA, Test Methods for Evaluating Solid Waste, Physical/Chemical Methods, SW-846, 3rd Ed.; U.S. Government Printing Office: Washington, DC, 1995.
3. U.S. EPA, Federal Register, 1995, 60, 37974-37980.
4. Link, D.D.; Walter, P.J.; Kingston, H.M., Environ. Sci. Technol., 1999, 33, 2469-2473.
5. Leppard, G.G.; Flannigan, D.T.; Mavrocordatos, D.; Marvin, C.H.; Bryant, D.W.; McCarry, B.E., Environ. Sci. Technol., 1998, 32, 3633-3639.