Beach Pollution Disappears Within a Very Short Distance
Ann Arbor, MI — Summer is a time for many Great Lakes residents to enjoy one of the regions best amenities, the beaches. However, in recent years, beaches have been closed up and down the Great Lakes coast, a cause for concern for not only the beach, but the Great Lakes as a whole. Many questions have arisen as to the source and extent of pollution.
Beaches are tested for fecal pollution using an indicator organism, the bacterium Escherichia coli (E. coli). When levels exceed a certain value, a water quality advisory or closing is issued. In this study, a public beach with chronic water quality problems was monitored side by side with a second beach site only 150 meters to the south. The public beach had several features that were suspect sources of pollution, including a large two-city block parking lot that sent stormwater runoff to the beach area and a snack bar with open garbage cans that attracted gulls and other birds. To make matters worse, the beach was located within a marina breakwall, resulting in low water circulation. The second beach site was free of these features.
"We were very surprised that a second beach only a short distance down the shoreline had very little pollution compared to the current public beach site," says Sandra McLellan, an Assistant Scientist at the University of Wisconsin-Milwaukee. Overall, the public beach exceeded the EPA recommended limit for E. coli 30% of the days tested, but the second site was only out of limit 10% of the time. This work shows that pollution sources very close to the beach can greatly influence water quality, and beach closings do not always reflect water quality in Lake Michigan as a whole.
One possible solution for beaches with similar pollution sources may be some simple coastal management strategies. Covering garbage cans and educating beach goers about the consequences of feeding gulls may reduce the negative impact these birds have on water quality. Mitigating stormwater that directly drains to beach areas could also improve water quality because stormwater is known to carry bacteria and other pollutants. If possible, beaches with a history of closings could be moved to a site with fewer pollution inputs, or these factors considered when new beach sites are planned.
Original Publication Information
Results of this study "Influence of Nearshore Water Dynamics and Pollution Sources on Beach Monitoring Outcomes at Two Adjacent Lake Michigan Beaches," are reported by Caitlin O. Scopel, Josh Harris and Sandra L. McLellan in the latest issue (Volume 32, No. 3, pp. 543-552) of the Journal of Great Lakes Research, published by the International Association for Great Lakes Research, 2006.
Contacts
For more information about the study, contact Sandra McLellan, Great Lakes WATER Institute, University of Wisconsin-Milwaukee, Milwaukee, WI 53204; mclellan@uwm.edu; (414) 382-1700.
For information about the Journal of Great Lakes Research, contact Marlene Evans, Editor, National Water Research Institute, Environment Canada, 11 Innovation Boulevard, Saskatoon, SK, S7N 3H5, Canada; jglr@ec.gc.ca; (306) 975-5310.
Links
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