Assessment of Water Quality in Roof-Harvested Rainwater Barrels in Greater Philadelphia

Abstract

A study of water quality parameters was conducted in 38 small-scale roof-harvested rainwater barrels (RHRB) located in urban and peri-urban Philadelphia, USA in winter (November-December) 2014 and summer (June-August 2016). Parameters included two fecal indicator bacteria (FIB) (Escherichia coli and Enterococcus spp.) measured using culture-based methods, eight potential enteric and opportunistic pathogens (Campylobacter jejuni, Acanthamoeba spp., Legionella spp., L. pneumophila, Naegleria fowleri, Pseudomonas aeruginosa, Mycobacterium avium and Mycobacterium intracellulare) measured using quantitative polymerase chain reaction (qPCR), and two metals (lead and zinc) using inductively coupled plasma mass spectrometry (ICP-MS). Fecal indicator bacteria were detected in greater than 60% RHRB samples and concentrations (up to >10 3 per 100 mL) exceeded US Food and Drug Administration (USFDA) irrigation water quality standards. Among the enteric and opportunistic pathogens tested, 57.9, 44.7, 21.1, 18.4, 5 and 3% were PCR positive for Legionella spp., M. intracellulare, M. avium, Acanthamoeba spp., P. aeruginosa, and C. jejuni, respectively. N. fowleri and L. pneumophila were not detected in any sample. The concentrations of enteric and opportunistic pathogens ranged from 10 2 to 10 7 gene copies/L of barrel water. Lead and zinc were each observed in 88.5% of RHRB but the concentrations did not exceed US Environmental Protection Agency (USEPA) standards for irrigating produce, with the exception of one zinc observation (2660 µg/L). Based on these data, it appears that the risk associated with metals in RHRB is likely to be low, as these barrels are only used for gardening and non-potable purposes. However, risks due to fecal and opportunistic pathogens may be higher due to exposure to aerosols during gardening activities and produce consumed raw, and should be investigated further.

Characterization of roof runoff microbial quality in four U.S. cities with varying climate and land use characteristics

“…More data on microbial quality of roof runoff is needed to inform treatment requirements for safe use of roof runoff. Consequently, roof runoff remains underutilized as an alternate water resource in the United States (Hamilton et al, 2018).…”

“…Previous studies assessed the occurrence and concentrations of fecal indicator organisms and potentially human-infectious pathogens in roof runoff. Most of these studies were conducted in Australia (Thomas and Greene, 1993;Verrinder and Keleher, 2001;Spinks et al, 2006;Chapman et al, 2008;Evans et al, 2006;Ahmed et al, 2008;Ahmed et al, 2010a;Ahmed et al, 2010b;Ahmed et al, 2011b), with fewer studies in the U.S. (Isquith and Winters, 1987;Kim et al, 2016;Kirs et al, 2017;Hamilton et al, 2018). Fecal indicator bacteria are usually abundant in roof runoff due to the access of small mammals and birds to roof surfaces (Bae et al, 2019;Ahmed et al, 2011b).…”

“…Both opportunistic pathogens and human enteric pathogens have been reported to exist in roof runoff (Crabtree et al, 1996;Kim et al, 2016;Kirs et al, 2017;Hamilton et al, 2018;Bae et al, 2019). Studies conducted in the U.S. focused mostly (Hamilton et al, 2018) or entirely (Kim et al, 2016) on the detection and quantification of opportunistic pathogens.…”

“…Both opportunistic pathogens and human enteric pathogens have been reported to exist in roof runoff (Crabtree et al, 1996;Kim et al, 2016;Kirs et al, 2017;Hamilton et al, 2018;Bae et al, 2019). Studies conducted in the U.S. focused mostly (Hamilton et al, 2018) or entirely (Kim et al, 2016) on the detection and quantification of opportunistic pathogens. Studies investigating the occurrence of human enteric pathogens in the U.S. are few, and these studies examined only 1 to 3 human enteric pathogens at a time, e.g., Salmonella (Isquith and Winters, 1987), Cryptosporidium spp.…”

Assessments of Roof-Harvested Rainwater in Disctrict Dir Lower, Khyber Pakhtunkhwa Pakistan

“…A suitable scheme should be implemented to remove the initial runoff from the storage tank to improve rainwater quality. At the same time, this process also reduces the quantity of roof-collected rainwater [23,24]. Many machine learning techniques are used to assess water [25][26][27][28][29][30].…”