Experts Weigh in on Waterborne Coronavirus Transmission
By Kelly A. Reynolds, MSPH, PhD
At the time of this writing, a global effort in social distancing is underway to minimize the spread of SARS-CoV-19 (the virus) and COVID-19 (the disease). Restaurants, bars and other businesses where people congregate are encouraged or mandated to close, while only essential services remain open. With water being a foundational element of good health and nutrition, water treatment and purification should be considered as essential services and remain in operation. Therefore, protection of water treatment professionals must be considered relative to the potential spread of highly infectious viruses via the waterborne route.
Recently the Water Research Foundation (WRF) assembled a panel of experts to discuss the potential for waterborne transmission of coronaviruses. The panel included representatives from the water and wastewater treatment industries, the Centers for Disease Control and Prevention (CDC) and academia. The webcast, available at the WRF website, focused on the latest research on CoV-19 and was attended by over 4,000 participants from 30 countries.1
Highlights from the March session included discussions on the potential spread of CoV-19 via the fecal-oral route, opening up the possibility for transmission routes to include water, wastewater and food. While person-to-person contact appears to be the primary route of transmission, more research is needed on the potential for other routes to be involved. Coronaviruses are known to be shed in stools of infected individuals in high concentrations.
Questions such as the survival times and disinfection efficacy of standard water and wastewater treatment works are also being considered. Speakers pointed participants to an updated guidance from the World Health Organization (WHO), specifically targeting water and sanitation practitioners and providers.2 WRF also announced a follow-up communication planned on April 16 from 3:30-5:00 p.m. EDT.
COVID-19 originally emerged from Wuhan, China, linked to large seafood and live-animal markets. On January 21, the first case was identified in the US and was determined to be exported from China following recent travel to the region. Since then, the infection has been identified as a global pandemic and cases have been reported in all 50 US states.
Scientists are scrambling to characterize important traits of the virus that may lead to mitigation of its spread.
Coronaviruses are not new. In fact, CoV-19 is the seventh known human strain. We are, however, still evaluating if this newly mutated strain has the same characteristics as other coronaviruses or the more extensively studied influenza viruses. While COVID-19 exhibits some similarity to the flu, there are also critical differences, in particular, the presence of CoV-19 viruses in the feces of some infected individuals.3,4 Fecal shedding has been observed with other coronavirus illnesses, such as SARS and MERS, but the CoV-19 virus does not appear to be as deadly as its genetic relatives.
We know that the CoV-19 can be transmitted from aerosols and also from direct contact with mucus membranes of the mouth, nose or eyes. Symptoms include fever, cough and shortness of breath and the estimated incubation time may range from two to 14 days. Infected individuals may exhibit no symptoms at all or the illness may range from mild to severe and even deadly. Deaths are usually due to advanced pneumonia and respiratory or multi-system organ failure.
The immunocompromised and elderly are most at risk for more severe adverse outcomes.
Water management options
Despite communications from multiple sectors, including government officials, health agencies and media outlets, consumers flocked to grocery stores to stock up on bottled water, citing fear about the safety of drinking water supplies. To date, data indicate that the municipal drinking-water supply is safe and that standard treatment protocols, such as filtration and disinfection, are effective against the coronavirus. Coronavirus is known to be more sensitive to disinfectants than other waterborne microbes, including our water quality indicator monitoring standard, E. coli. This includes common disinfectants such as chlorine, UVC light, chlorine dioxide, paracetic and peroxyacetic acids and quaternary ammonium compounds.
While there is a chance that CoV-19 can persist for long periods of time (perhaps hours to days or longer) in water, wastewater and septic tank effluent, properly functioning systems are considered low-risk scenarios. CoV-19 has not been detected in drinking water or treated wastewaters. As with any waterborne pathogen, however, maintenance of proper treatment levels, including chlorine residuals, is important to ensure water safety. Free chlorine dosed to achieve residuals of 0.2 to 0.5 mg/L have been found to readily inactivate other coronaviruses and are likely to be effective against the current pandemic strain.
Given that outbreaks from other fecal pathogens have occurred due to lack of proper drinking or wastewater treatment, POU devices offer additional assurances to consumers that effective treatments are maintained to reduce exposures. For more information on community mitigation practices, the CDC provides a guidance on standard infection control practices targeting hand hygiene, surface disinfection and wastewater, drinking water and recreational water treatment.5
Although properly treated water sources are expected to be low risk, worker exposures to untreated waste waters or filters with potentially concentrated hazards may be a valid concern. Contaminated wastewater that is not properly collected and treated has been associated with a number of drinking-water outbreaks in the US. Protective measures and effective practices are in place for wastewater treatment and worker protection, and should be diligently adhered to.
There is no evidence that water and wastewater treatment and service workers need additional protection beyond current practices; however, now is a good time to provide a refresher and instill renewed compliance with current recommendations. CDC and OSHA guidelines are available for workers handling hazardous, infectious wastes and have been updated with coronavirus specific information.6
Basic hygiene practices for workers include7:
• Wash hands with soap and water immediately after handling human waste or sewage.
• Avoid touching face, mouth, eyes, nose or open sores and cuts while handling human waste or sewage.
• After handling human waste or sewage, wash your hands with soap and water before eating or drinking.
• After handling human waste or sewage, wash your hands with soap and water before and after using the toilet.
• Before eating, removed soiled work clothes and eat in designated areas away from human waste and sewage-handling activities.
• Do not smoke or chew tobacco or gum while handling human waste or sewage.
• Keep open sores, cuts and wounds covered with clean, dry bandages.
• Gently flush eyes with safe water if human waste or sewage contacts eyes.
• Use waterproof gloves to prevent cuts and contact with human waste or sewage.
• Wear rubber boots at the worksite and during transport of human waste or sewage.
• Remove rubber boots and work clothes before leaving worksite.
• Clean contaminated work clothing daily with 0.05-percent chlorine solution (one part household bleach to 100 parts water).
Preparedness over fearfulness
Participants from the WRF webcast urged individuals and communities to “replace fear with preparedness,” recognizing that panic and fear may cause unintended adverse health consequences in the future. As individuals we can support common prevention measures (such as to avoid touching areas of your face with unwashed hands), practice social distancing (some studies are suggesting up to 12 feet) and stay home when ill.
The coronavirus pandemic reveals a level of uncertainty related to public-health response that has never been seen before. Details are changing daily, if not hourly. We are being inundated with information and in some cases, misinformation. The CDC website is frequently updated with information from new research and monitoring information and is a primary source for the most current information on COVID-19 (www.cdc.gov/COVID19).
(1) Coronavirus Research Update. The Water Research Foundation. https://www.waterrf.org/event/coronavirus-research-update. Accessed March 21, 2020.
(2) Water, sanitation, hygiene and waste management for COVID-19. https://www.who.int/publications-detail/water-sanitation-hygiene-and-waste-management-for-covid-19. Accessed March 21, 2020.
(3) Yeo C, Kaushal S, Yeo D. Enteric involvement of coronaviruses: is faecal–oral transmission of SARS-CoV-2 possible? Lancet Gastroenterol Hepatol. 2020;5(4):335-337. doi:10.1016/S2468-1253(20)30048-0
(4) Zhang W, Du RH, Li B, et al. Molecular and serological investigation of 2019-nCoV infected patients: implication of multiple shedding routes. Emerg Microbes Infect. 2020;9(1):386-389. doi:10.1080/22221751.2020.1729071
(5) Municipal Water and COVID-19. https://www.cdc.gov/coronavirus/2019-ncov/php/water.html. Accessed March 21, 2020.
(6) Safety and Health Topics | COVID-19–Control and Prevention. Occupational Safety and Health Administration. https://www.osha.gov/SLTC/covid-19/controlprevention.html#solidwaste. Accessed March 21, 2020.
(7) Guidance for Reducing Health Risks to Workers Handling Human Waste or Sewage | Global Water, Sanitation and Hygiene | Healthy Water. CDC. https://www.cdc.gov/healthywater/global/sanitation/workers_handlingwaste.html. Accessed March 21, 2020.
About the author
Dr. Kelly A. Reynolds is a University of Arizona Professor at the College of Public Health; Chair of Community, Environment and Policy; Program Director of Environmental Health Sciences and Director of Environment, Exposure Science and Risk Assessment Center (ESRAC). She holds a Master of Science Degree in public health (MSPH) from the University of South Florida and a doctorate in microbiology from the University of Arizona. Reynolds is WC&P’s Public Health Editor and a former member of the Technical Review Committee. She can be reached via email at firstname.lastname@example.org