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CAN RAPID MEASURES OF RECREATIONAL WATER QUALITY PREDICT SWIMMING ASSOCIATED GASTROINTESTINAL ILLNESS?
Citation:
WADE, T. J., R. L. CALDERON, E. A. SAMS, M. BEACH, K. P. BRENNER, A. H. WILLIAMS, AND A. P. DUFOUR. CAN RAPID MEASURES OF RECREATIONAL WATER QUALITY PREDICT SWIMMING ASSOCIATED GASTROINTESTINAL ILLNESS? ENVIRONMENTAL HEALTH PERSPECTIVES. National Institute of Environmental Health Sciences (NIEHS), Research Triangle Park, NC, 114(1):24-28, (2004).
Impact/Purpose:
The objectives of this research are: (1) to evaluate rapid state-of-the-art measuement methods of pathogens that may indicate the presence of fecal pollution in recreational waters (beaches); (2) to obtain, jointly with a sister laboratory (NHEERL), a new set of water quality data and related health effects data at a variety of beaches across the U.S., in both marine and non-marine waters; (3) to analyze the research data set to evaluate the utility of the tested measurement methods, the new EMPACT monitoring protocol, and the health effects data / questionnaire, in order to establish a relationship between measured pathogens and observed health effects; and (4) to communicate the results to the Office of Water in support of their efforts to develop new state and/or federal guidelines and limits for water quality indicators of fecal contamination, so that beach managers and public health officials can alert the public about the potential health hazards before exposure to unsafe water can occur.
Description:
Standard methods to measure recreational water quality require at least 24 hours to obtain results making it impossible to assess the quality of water within a single day. Methods to measure recreational water quality in two hours or less have been developed. Application of rapid methods could give considerably more accurate and timely assessments of recreational water quality. A prospective study of beach-goers was conducted at two Great Lakes beaches to examine the association between recreational water quality, obtained using rapid methods, and gastrointestinal (GI) illness following swimming. Beach-goers were asked about swimming and other beach activities and ten to twelve days later were asked about the occurrence of gastrointestinal symptoms. Water samples were tested for Enterococci and Bacteroides using the quantitative polymerase chain reaction method. Significant trends between increased GI illness and Enterococci were observed at the Lake Michigan beach, and a positive trend was observed for Enterococci at the Lake Erie beach. The association remained significant for Enterococci when the two beaches were combined. A positive trend was observed for Bacteroides at the Lake Erie beach, but no trend was observed at the Lake Michigan beach. Enterococci samples collected at 8:00 am were predictive of gastrointestinal illness that day. The association between Enterococci and illness strengthened as time spent swimming in the water increased. This is the first study to show that water quality measured by rapid methods can predict swimming-associated health effects.