A review on microbial contaminants in stormwater runoff and outfalls: Potential health risks and mitigation strategies

Abstract

Editor: Patricia HoldenDemands on global water supplies are increasing in response to the need to provide more food, water, and energy for a rapidly growing population. These water stressors are exacerbated by climate change, as well as the growth and urbanisation of industry and commerce. Consequently, urban water authorities around the globe are exploring alternative water sources to meet ever-increasing demands. These alternative sources are primarily treated sewage, stormwater, and groundwater. Stormwater including roof-harvested rainwater has been considered as an alternative water source for both potable and non-potable uses. One of the most significant issues concerning alternative water reuse is the public health risk associated with chemical and microbial contaminants. Several studies to date have quantified fecal indicators and pathogens in stormwater. Microbial source tracking (MST) approaches have also been used to determine the sources of fecal contamination in stormwater and receiving waters. This review paper summarizes occurrence and concentrations of fecal indicators, pathogens, and MST marker genes in urban stormwater. A section of the review highlights the removal of fecal indicators and pathogens through water sensitive urban design (WSUD) or Best Management Practices (BMPs). We also discuss approaches for assessing and mitigating health risks associated with stormwater, including a summary of existing quantitative microbial risk assessment (QMRA) models for potable and non-potable reuse of stormwater. Finally, the most critical research gaps are identified for formulating risk management strategies.Crown

Response to the comments by Mr. William Minervini on “Organism Detection in Permeable Pavement Parking Lot Infiltrates at the Edison Environmental Center, New Jersey”

“…Also, it was never claimed curb cut runoff values were absolute, just representative. Our mean values are within the range reported in the literature (Ahmed, Hamilton, Toze, Cook, & Page, 2019). It should also be noted that sampling was done for research purposes only and not for regulatory permits.…”

What do we know about the SARS-CoV-2 coronavirus in the environment?

“…If this virus is not eradicated, we should think on further screening focusing on wastewater (Martínez-Puchol et al, 2020 -have recently published a paper dealing with related aspects), but also on sewage sludge (as shown by Nag et al, 2020 -evaluating survival of bacteria and viruses causing different diseases, as well as in previous papers, such as that by Zhao and Liu, 2019), soils and sediments (Katz et al, 2018;Nag et al, 2020;Zhao and Liu, 2019), crops (Ahmed et al, 2019;Nag et al, 2020;Zhao and Liu, 2019), animals (Pruvot et al, 2019), surface and ground-waters (Corsi et al, 2014;Givens et al, 2016). Further research should also focus on eventual technical treatments, including biosorbents and other materials to retain and/or inactive this and other pathogens circulating in these environmental compartments, before and after going out from wastewater treatment plants (in case of these treatment systems existing, as it could be worse, with spreading of untreated wastes).…”

Human Fecal Pollution Monitoring and Microbial Risk Assessment for Water Reuse Potential in a Coastal Industrial–Residential Mixed-Use Watershed

“…The Chak Mak Canal runs through the Map Ta Phut Sub-district, which hosts 20,980 households, while the Nam Hu Canal passes by the Nean Phra Sub-district, which has 13,991 households. Stormwater runoff during rainfall events, even though not yet characterized in this study, potentially carries additional general or animal fecal microorganisms into the receiving water (Ahmed et al, 2019;Lee et al, 2020;Powers et al, 2020). However, the already-high level of fecal contamination in dry weather, as shown in this study, and especially the high percentage of samples exceeding the total coliform standards, has raised the attention for water quality mitigation strategies for expected higher pollution levels in the rainy season.…”