| Massive Microbiological Groundwater Contamination Associated with a Waterborne Outbreak in Lake Erie, South Bass Island, Ohio Theng-Theng Fong,1 Linda S. Mansfield,2 David L. Wilson,3,4 David J. Schwab,5 Stephanie L. Molloy,6 and Joan B. Rose1,6 1Department of Crop and Soil Science, 2Department of Microbiology and Molecular Genetics, 3National Food Safety and Toxicology Center, and 4Department of Food Science and Human Nutrition, Michigan State University, East Lansing, Michigan, USA; 5National Oceanic and Atmospheric Administration Great Lake Environmental Research Laboratory, Ann Arbor, Michigan, USA; 6Department of Fisheries and Wildlife, Michigan State University, East Lansing, Michigan, USA Abstract
Background: A groundwater-associated outbreak affected approximately 1,450 residents and visitors of South Bass Island, Ohio, between July and September 2004. Objectives: To examine the microbiological quality of groundwater wells located on South Bass Island, we sampled 16 wells that provide potable water to public water systems 15–21 September 2004. Methods: We tested groundwater wells for fecal indicators, enteric viruses and bacteria, and protozoa (Cryptosporidium and Giardia) . The hydrodynamics of Lake Erie were examined to explore the possible surface water–groundwater interactions. Results: All wells were positive for both total coliform and Escherichia coli. Seven wells tested positive for enterococci and Arcobacter (an emerging bacterial pathogen) , and F+-specific coliphage was present in four wells. Three wells were positive for all three bacterial indicators, coliphages, and Arcobacter ; adenovirus DNA was recovered from two of these wells. We found a cluster of the most contaminated wells at the southeast side of the island. Conclusions: Massive groundwater contamination on the island was likely caused by transport of microbiological contaminants from wastewater treatment facilities and septic tanks to the lake and the subsurface, after extreme precipitation events in May–July 2004. This likely raised the water table, saturated the subsurface, and along with very strong Lake Erie currents on 24 July, forced a surge in water levels and rapid surface water–groundwater interchange throughout the island. Landsat images showed massive influx of organic material and turbidity surrounding the island before the peak of the outbreak. These combinations of factors and information can be used to examine vulnerabilities in other coastal systems. Both wastewater and drinking water issues are now being addressed by the Ohio Environmental Protection Agency and the Ohio Department of Health. Key words: Arcobacter, groundwater, microbiological contamination, outbreak, viruses, waterborne. Environ Health Perspect 115:856–864 (2007) . doi:10.1289/ehp.9430 available via http://dx.doi.org/ [Online 6 February 2007]
Address correspondence to J.B. Rose, Department of Fisheries and Wildlife, 15 Natural Resources, Michigan State University, East Lansing, MI 48824-1222 USA. Telephone: (517) 432-4412. Fax: (517) 432–1699. E-mail: rosejo@msu.edu We thank J. Linz for providing guidance in the culturing of Campylobacter and Arcobacter ; the Ohio Environmental Protection Agency for their funding and assistance in sampling ; and R. Ives, T. Jenkins, and M. Wong for assisting with samples processing. This study was supported by the NOAA Center of Excellence for Great Lakes and Human Health (CA4/III-08) and the Centers for Emerging Infectious Diseases and Microbial Pathogenesis at Michigan State University. The authors declare they have no competing financial interests. Received 16 June 2006 ; accepted 6 February 2007.
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