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Septic systems and rainfall influence human fecal markers and indicator organisms occurrence in private wells in southeastern Pennsylvania

February 19, 2020

In the United States approximately 48 million people are served by private wells. Unlike public water systems, private well water quality is not monitored and there are few studies on the extent and sources of contamination of private wells. We extensively investigated five private wells to understand the variability in microbial contamination, the role of septic systems as sources of contamination, and the effect of rainfall on well water quality. From 2016-2017, weekly or biweekly samples (n= 105) were collected from 5 private wells in rural Pennsylvania. Samples were tested for general water quality parameters, conventional and sewage-associated microbial indicators, and human pathogens. Total coliforms, human Bacteroides (HF183), and pepper mild mottle virus were detected at least once in all wells. Regression revealed significant relationships between HF183 and rainfall 8-14 days prior to sampling and between total coliforms and rainfall 8-14 or 0-14 days prior to sampling. Dye tracer studies at 3 wells confirmed the impact of household septic systems on well contamination. Microbiological measurements, chemical water quality data, and dye tracer tests provide evidence of human fecal contamination in the private wells studied, suggesting that household septic systems are the source of this contamination.

Publication Year 2020
Title Septic systems and rainfall influence human fecal markers and indicator organisms occurrence in private wells in southeastern Pennsylvania
DOI 10.1021/acs.est.9b05405
Authors Heather Murphy, Shannon McGinnis, Ryan Blunt, Joel P. Stokdyk, Jingwei Wu, Alexander Cagle, Donna Denno, Susan K. Spencer, Aaron Firnstahl, Mark A. Borchardt
Publication Type Article
Publication Subtype Journal Article
Series Title Environmental Science & Technology
Index ID 70208832
Record Source USGS Publications Warehouse
USGS Organization Upper Midwest Water Science Center