AWWA SYM53629

In order to ensure compliance with the filtration waiver granted to theMassachusetts Water Resources Authority under the Environmental ProtectionAgency's Surface Water Treatment Rule, the Metropolitan District Commission (MDC)has endeavored to develop an extensive plan for watershed protection. Landdevelopment around the Wachusett Reservoir watershed has resulted in increasingpressure for prevention of reservoir contamination. With development comes ahigher risk of non point source fecal contamination that includes septic systems,dairy/cattle farms and horse stables. Wildlife native to the watershed can alsoresult in fecal inputs. Enhanced watershed management could utilize microbialindicators of fecal pollution that are source-specific. The ability todiscriminate between sources of microbial inputs would enable the watershedmanagement division of the MDC to target preventative and corrective actionsappropriately, thus conserving resources. Tools that allow source water managersto target remedial activities toward the appropriate microbial input sources arenecessary. Two promising bacteriologically-based testing methods that might beused in conjunction with standard coliform testing are the alternative indicatorssorbitol-fermenting Bifidobacteria and Rhodococcus coprophilus. Promising viralindicators are male-specific or F+coliphages. These organisms have been studiedfor their association with source animal feces and sewage. Laboratory testmethods were developed to determine the effectiveness of sorbitol-fermentingBifidobacteria, Rhodococcus coprophilus, and F+ RNA coliphages as source-specificindicators of fecal contamination. The bacteriologically-based indicator organismtests were examined in a yearlong survey of three sampling sites within the MDCmanaged Wachusett Reservoir watershed. Samples were collected monthly from March1998 through March 1999. Sorbitol- fermenting Bifidobacteria were monitored as anindicator of recent human sewage contamination, and Rhodococcus coprophilus weremonitored as an indicator of agricultural grazing animal fecal contamination. F+RNA coliphages were isolated and serotyped to distinguish between human andnon-human sources of fecal contamination. A comparison of the bacteriologicallybased indicator organisms against the established F+ RNA coliphage serotypingmethod was conducted to validate their utility. Several water quality parameterswere measured as part of the survey, including total and fecal coliforms,temperature, pH, total and dissolved organic carbon and turbidity. Includes 18 references, figures.