Human-associated indicator bacteria and human-specific viruses in surface water: a spatial assessment with implications on fate and transport

Authors: LENAKER, PETER - U.S. GEOLOGICAL SURVEY (USGS); CORSI, STEVEN - U.S. GEOLOGICAL SURVEY (USGS); OLDS, HAYLEY - U.S. GEOLOGICAL SURVEY (USGS); MCLELLAN, SANDRA - UNIVERSITY OF WISCONSIN; BORCHARDT, MARK; DILA, DOBORAH - UNIVERSITY OF WISCONSIN; SPENCER, SUSAN; BALDWIN, AUSTSIN - U.S. GEOLOGICAL SURVEY (USGS)

Submitted to: Environmental Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/26/2018
Publication Date: 10/15/2018
Citation: Lenaker, P.L., Corsi, S.R., Olds, H.T., McLellan, S.L., Borchardt, M.A., Dila, D.K., Spencer, S.K., Baldwin, A.K. 2018. Human-associated indicator bacteria and human-specific viruses in surface water: a spatial assessment with implications on fate and transport. Environmental Science and Technology. 52(21):12162-12171. https://doi.org/10.1021/acs.est.8b03481.
DOI: https://doi.org/10.1021/acs.est.8b03481

Interpretive Summary: In rivers polluted with fecal material the question often asked is to what extent are human sources, like sanitary sewers and septic systems, responsible for the fecal pollution. We studied the Menomonee River Basin in southeastern Wisconsin, where the land use ranges from mostly agriculture upstream to mostly urban downstream. Microorganisms that are only found in humans were used to quantify the amount of human fecal pollution in the river. Using this approach we were able to identify the specific watersheds within the river basin that were contributing the most fecal pollution. During rainy periods the amount of fecal pollution added by each watershed varied by a factor of one million. The difference among watersheds was not as great during dry periods. The results of this study can be used by water resource managers to understand the land use patterns, environmental factors and watershed properties that lead to human fecal pollution in rivers.

Technical Abstract: Fecal pollution from human sources was spatially quantified by measuring two human-associated indicator bacteria (HIB) and eight human-specific viruses (HSV) at six stream locations in the Menomonee River watershed in Milwaukee, Wisconsin from April 2009 to March 2011. A custom, automated pathogen sampler was deployed at each location providing unattended, flow-weighted, large-volume (30-913 L) sampling. In addition, 70 wastewater influent samples were composited over discrete seven-day periods from the two Milwaukee water reclamation facilities (WRF). Of the eight HSV only three were detected, present in up to 38% of the 228 stream samples, while at least one HSV was detected in all WRF influent samples. HIB occurred significantly more often with higher concentrations than the HSV in stream and WRF influent samples. A negative HSV yield from the most downstream sub-watershed of the Menomonee River, and in contrast, a positive HIB yield from this same sub-watershed emphasizes the complexity in fate and transport properties between HSV and HIB. This warrants the need for continued site-specific evaluations to fully explain fate and transport properties of HSV and HIB. This study demonstrates the utility of analyzing multiple pathogens for a more complete assessment of fecal contamination at the watershed level.