December 8, 2011
Keeping Our Beaches Safe
New wireless sensor device rapidly detects E. coli in water samples
Fecal contamination of public beaches caused by sewage overflow is both dangerous for swimmers and costly for state and local economies. Current methods to detect Escherichia coli, a bacterium highly indicative of the presence of fecal matter in water, typically require 24-48 hours to produce a result. A new, accurate, and economical sensor-based device capable of measuring E. coli levels in water samples in less than 1-8 hours could serve as a valuable early warning tool and is described in an article in Environmental Engineering Science, a peer-reviewed journal published by Mary Ann Liebert, Inc. (http://www.liebertpub.com). The article is available online at http://www.liebertpub.com/mcontent/files/EES-2011-0148-Nijak_5P.pdfThe article provides a detailed description of the autonomous, wireless, in-situ (AWISS), battery-powered device, which contains a prototype optical sensor that can measure changes in fluorescence intensity in a water sample. In the presence of E. coli bacteria an enzymatic reaction will cause an increase in fluorescence. The AWISS can detect high concentrations of bacteria in less than 1 hour and lower concentrations in less than 8 hours.
Jeffrey Talley (Johns Hopkins University, Baltimore, MD) and colleagues (Environmental Technology Solutions, Gilbert, AZ, and the U.S. Army Corps of Engineers, Vicksburg, MS), present the results of a 7-day demonstration project using the AWISS device. The detection system developed is able to collect and analyze a water sample every 6 hours and to employ wireless transmission to send the data collected to remote monitoring stations. The authors compare the effectiveness of the AWISS to other E. coli detection methods currently approved by the U.S. Environmental Protection Agency (EPA).
"Pathogens in the aquatic environment pose significant human and ecological health risks. The work of Professor Talley and his colleagues in developing a remote sensing instrument to detect and transmit pathogen water quality information is a major advance in helping safeguard human health," says Domenico Grasso, PhD, Editor-in-Chief and Vice President for Research, Dean of the Graduate College, University of Vermont (Burlington).
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