Applying Our Environmental Modeling Tools in the Fight Against COVID-19
There is no doubt that the ongoing COVID-19 pandemic has impacted all of us, to varying degrees, either directly or indirectly. While 2020 will live on in history as a year of epidemiological and economic devastation, a silver lining can be found in how the pandemic has shaped the course of scientific research: insights and collaboration within the scientific community progressed on a global scale at a pace we have never quite seen before. It did not take long for us to realize that our tools and expertise in environmental modeling could play a role in the arms race between the SARS-CoV-2 virus and scientific research.
Waterborne’s Raghu Vamshi and Scott Dyer, in collaboration with the American Cleaning Institute, LeTourneau University, and the University of Arkansas, have been working to analyze the fate and transport of SARS-CoV-2 in U.S. wastewater and surface waters using iSTREEM®. This is a novel application of iSTREEM®, which is a public, web-based and spatial model designed to estimate concentrations of down-the-drain materials in wastewater effluent, receiving waters, and drinking water.
It seemed like everyone and everything was asked to pivot during the pandemic, and iSTREEM® was no different; the application of this fate and transport model was investigated as a new tool for COVID-19 tracking efforts. Since the viral RNA is excreted from infected individuals, wastewater-based epidemiology can provide valuable insights into upstream positive caseloads considering the physical and economic challenges of clinical testing for viral infection. iSTREEM® was deemed a suitable application for this research due to its up-to-date waterway connection to the U.S. population, wastewater treatment infrastructure, and river network.
One way that iSTREEM® was used in COVID-19 detection was to estimate wastewater and surface water concentrations of the virus for the continental U.S. The monitoring data (i.e., viral loads taken from highly significant regressions of measured influent concentrations from numerous Ohio wastewater treatment plants (WWTPs)) was paired with 10-day cumulative positive COVID-19 caseloads for inputs into the model. Removal of SARS-CoV-2 via WWTPs was determined and estimated from recent studies conducted by the University of Arkansas and augmented from literature search, which also considered surrogate viruses and organic chemicals. First-order decay rates were based on loss rates of various viruses in surface waters and expert knowledge of highly biodegradable materials. All this information was used for iSTREEM® modeling of the continental U.S. over multiple temporal scales during the course of the pandemic. The analysis of results at the national scale clearly indicated that WWTPs are highly efficient in removing SARS-CoV-2.
Fortunately, this research showed that residual RNA fragments that remained in wastewater effluent were diluted in the surface waters, resulting in concentrations below current detection limits. It can be expected that treatment of drinking water will result in even greater loss of viral fragments leading to a highly confident assessment that SARS-CoV-2 does not pose a health risk to the population in the U.S. via drinking water. This is the first study to provide quantitative data at a national scale to support these claims. Stay tuned to our future newsletter for release of the publication describing this project!
The incorporation of wastewater data in epidemiology may not be a brand new concept, but the COVID-19 pandemic is certainly solidifying wastewater epidemiology as critical tool. In fact, The University of California Center for Information Technology Research in the Interest of Society (CITRIS) and researchers of UC Merced have developed a global dashboard for SARS-CoV-2 wastewater monitoring efforts. The aptly named “COVID19Poops Dashboard” enables global collaboration in the wastewater epidemiology efforts being used in the fight against COVID-19. Check out the dashboard and see what monitoring efforts are taking place near you!