The Ohio Water Resources Center (Ohio WRC) is coordinating with the Ohio Department of Health (ODH), Ohio EPA, the U.S. Environmental Protection Agency in Cincinnati wastewater study to monitor trends and changes of COVID-19 in communities. The study includes statewide sampling from Ohio’s municipal wastewater treatment systems to determine the presence of coronavirus ribonucleic acid (RNA) fragments.
The sampling is being coordinated in partnership with wastewater utility departments in Ohio’s largest municipal areas, as well as medium and small communities. The samples are analyzed at the local Universities including Ohio State University, University of Toledo, Kent State University, University of Akron and Bowling Green State University in addition to US EPA lab and commercial labs. Since there is no standard method developed for this type of monitoring, each lab uses their optimized sample processing, RNA extraction and RT-PCR or dd-PCR, leveraging the lab resources. The laboratory network is monthly validating the comparability of the results in the network by splitting one sample and sending it to all the laboratories for analysis.
Other common QA/QC protocols are followed by all the participating utilities and laboratories, including chain of custody forms, negative and positive controls, internal processing controls, BSL2+ protocols and other.
The goal of the wastewater analysis is to provide an early warning of gene copies increasing in the sewage from communities, therefore our methods are trying to minimize the known virus decay due to time and increased temperatures. We collect 24-hour composite sample (or grab composite in wastewater treatment facilities without composite sampler) and keep it at 4oC until processing. We process the fresh samples (no pasteurization) as soon as possible (within 24 hours of collection) in order to avoid further RNA fragments degradation.
The results are being normalized for flow during the sample collection and being presented as million gene copies (MGC) per day. No other data normalization is performed - data are not being corrected for inhibition or percent recovery. Not normalizing for wastewater flow could lead to drop of RNA signal due to wastewater dilution during rain events, but it is not ideal due to different inputs into the collection systems that can affect the RNA fragments concentrations (industrial inputs and other). We are working on developing method that will enable us to recalculate the RNA fragments numbers to grams of human fecal material in the wastewater.