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Back to Press ReleasesSource: Charles Tseng (219)989-2403 FOR IMMEDIATE RELEASE
May 31, 2002 After a cold and wet spring, it is finally time to get to the serious business of going to the beach. However, water contamination, which happens with some frequency during the summer along the southern Lake Michigan shoreline, can lead to beach closings and cancelled plans. Illinois-Indiana Sea Grant (IISG) scientists are using the precision of DNA fingerprinting to pinpoint sources of E. coli that can lead to water contamination and beach closings. In Lake Michigan, high levels of E. coli are the main cause of area beach closures during the summer. By knowing the exact source of the outbreaks, municipalities can direct their prevention efforts where they may be most effective. This knowledge may also help local officials as they assess the risk of an outbreak. New thinking holds that wildlife bacteria is less of a health threat to people than bacteria from other humans. Charles Tseng and Evert Ting, biologists at Purdue University Calumet, have tracked the specific host species from over 500 E. coli samples. "These E. coli DNA fingerprints of known sources will be used to determine the source of E. coli from environmental samples. To date, DNA fingerprints of over 600 insolates from beach sand and lake water have been prepared," said Tseng. "The goal is to create a comprehensive E. coli database that will eventually have over 1,000 samples." E. coli is a bacterium found in the digestive tract of humans, farm animals, birds and other wildlife animals. When the bacterium is detected in water in significant numbers it indicates fecal contamination. While E. coli itself is harmless in most cases, its presence indicates that more harmful bacteria are also likely to be present in the water. "Children, senior citizens and those who have weakened immune systems are most at risk from these bacteria," said Leslie Dorworth, IISG aquatic ecology specialist, at Purdue University Calumet, who is also IISG's representative on the E. coli Interagency Task Force, and its outreach chair. "High E. coli counts are frequently caused by overflowing storm-water and sewage systems. Sewage treatment plants often do not have sufficient capacity to retain and process excess water from heavy rains," explained Dorworth. But, she added, many times we have beach closings when there is little rain. In these cases, contamination may come from any number of sources, including failed septic systems, marinas or wildlife in or near the water. "Municipalities have only so much money to spend on prevention. It helps to know where it will do the most good," said Dorworth. For educators and concerned organizations, IISG and the E. coli Task Force have created a series of posters that provide clear and concise information about a range of beach and water quality issues, such as How does E. coli get into the lake?, along with ideas to help protect the lake. They can be accessed on the IISG Web site at http://www.iisgcp.org/water/beach/beach.htm. IISG has also developed water quality fact sheets that can be ordered online at http://www.iisgcp.org/water/wic/wic.htm . --30-- The Illinois-Indiana Sea Grant College Program is one of 30 National Sea Grant College Programs. Created by Congress in 1966, Sea Grant combines university, government, business and industry expertise to address coastal and Great Lakes needs. Funding is provided by the National Oceanic Atmospheric Administration (NOAA), U. S. Department of Commerce, Purdue University at West Lafayette, Indiana, and the University of Illinois at Urbana-Champaign.
Irene Miles |
