Sewer Slime can Hang on to SARS-CoV-2 RNA from Wastewater

From the ACS Press Room Sewer Slime can Hang on to SARS-CoV-2 RNA from Wastewater

“Accumulation of SARS-CoV‑2 RNA in Sewer Biofilms”

ACS ES&T Water

During the COVID-19 pandemic, monitoring the levels of SARS-CoV-2 RNA in wastewater entering treatment plants has been one way that researchers have gauged the disease’s spread. But could the slimy microbial communities that line most sewer pipes affect the viral RNA they encounter? In a first-of-its-kind study, researchers report in ACS ES&T Water that sewer slime can accumulate SARS-CoV-2 RNA, which could decompose or slough off later, potentially impacting the accuracy of wastewater epidemiology studies. As the water and sludge from people’s homes converge in sewers, some of the solids settle out, and gooey microbial biofilms build up within the pipes. Previous researchers have shown that RNA viruses, such as poliovirus, enteroviruses and noroviruses, can get trapped and collect in this slime. Yet whether the sticky material can also accumulate SARS-CoV-2 viral particles or RNA from wastewater is unknown. Nicole Fahrenfeld and colleagues previously detected the virus’s RNA in sewer deposits from a university dormitory with a low number of COVID19 cases, but the amount was too low to accurately assess. So, the team wanted to see if biofilms could incorporate SARS-CoV-2 RNA from untreated wastewater during times

of low and high COVID-19 incidence. To grow a simulated sewer slime, the researchers continuously pumped raw wastewater into a cylindrical tank with removable pieces of polyvinyl chloride (PVC) inside. They conducted two 28-day experiments, removing PVC plates every few days to assess the biofilm’s composition. Then the team used the method called reverse transcription quantitative polymerase chain reaction to measure the abundance of SARS-CoV -2 RNA and pepper mottle virus (an indicator of human feces) RNA in the untreated wastewater and the biofilms.

In August and September 2020, the levels of SARSCoV-2 RNA were too low to accurately measure in both the simulated sewer slime and the wastewater from which it grew. These results align with a low incidence of COVID-19 infections at that time, the researchers say. Then, during November and December 2020, although SARS -CoV-2’s presence in the wastewater itself was still low, its RNA levels increased in the slime. The amount of pepper mottle virus RNA plateaued within the first week of growth, indicating that the rise of SARS-CoV

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The Doherty Award is given for excellence in chemical research or chemistry teaching, meritorious service to ACS, new chemical methodology (for the industry), solution of pollution problems, and advances in curative or preventive chemotherapy. Nominees may come from industry, academia, government, or small business. The nominee should be a resident member in the area served by the ACS DFW Local Section, and the work should have been performed here. The award is $1500 and an engraved plaque. The Schulz Award is given to high school chemistry teachers, who, like the late Dr. Werner Schulz, bring that something extra to the teaching of chemistry. The nominee and/or nominator need not be ACS members. Nominees should show excellence in chemistry teaching, as demonstrated by testimonials from students and fellow teachers, results in student competitions, and diligence in updating and expanding scientific/ teaching credentials. The award is $1500 and an engraved plaque. The DFW Section instituted the Chemistry Ambassador Award to recognize an outstanding Section member who has made a significant impact by promoting chemistry to the community. The 2022 Chemistry Ambassador of the Year award is based on peer or self-nominations to the selection committee. Submissions should be one page in length and address the community outreach activities either through teaching, service, or working with legislators to affect public policy. Submissions will be evaluated on the impact made, which may include but not limited to how many people were reached, impact on individual people in the community, and exemplary commitment to the promotion of chemistry in the community. The award is $1000. Each nomination should contain a completed nomination form, a cover letter highlighting the nominee’s accomplishments, and a copy of the CV. One or two additional letters may accompany nominations. The nomination package should be sent by email as a single pdf file Dr. Gabriele Meloni at gabriele.meloni@utdallas.edu. Nominations remain active for five years but should be updated annually.

The deadline is May 01, 2022

From the ACS Press Room Why Some Stony Coral Species are Better at Surviving Ocean Acidification

“Faster Crystallization during Coral Skeleton Formation Correlates with Resilience to Ocean Acidification” Journal of the American Chemical Society

Hard corals grow by generating calcium carbonate (CaCO3) from seawater and adding it to their skeletons, where it crystallizes. This process — and coral survival — are threatened by ocean acidification. However, scientists report in the Journal of the American Chemical Society that corals produce the CaCO3 in compartments protected from seawater and not, as previously believed, in exposed locations. The findings, and differing crystallization rates, could explain why some species are more resilient to this threat. Stony corals extract calcium and carbonate ions from seawater to make CaCO3, which is then attached to the growing skeleton in the form of amorphous particles that gradually harden into the lesssoluble “aragonite” crystal structure. Conventional wisdom holds that the particles form and grow in a 2-micron-thick layer of liquid on the skeleton surface known as the extracellular calcifying fluid (ECF). Because of photosynthesis by symbiotic organisms in the coral, the ECF’s pH rises in the daytime and then drops again each night. Normally, that wouldn’t be a problem, but because it is partly exposed to seawater, the ECF also acidifies to some degree when seawater pH declines. That would interfere with CaCO3 formation and deposition, and kill corals that are most sensitive to a drop in pH, according to Pupa U. P. A. Gilbert and colleagues. If, instead, nucleation and growth of CaCO3 particles occur in intracellular compartments protected from seawater and the ECF — as Gilbert’s group had recently hypothesized — then even sensitive species could have a chance at surviving acidification, as long as the pH doesn’t go too low. The researchers decided to settle this question. In coral samples, the team detected amorphous CaCO3 particles in a layer of cells that lie above the ECF. This finding is consistent with the growth of the particles inside closed vesicles — or tiny sacs — within these cells, the researchers say. That means the particles are formed safely away from seawater and not in the ECF. However, once attached to the growing skeleton surface, they’re exposed to the ECF, where they’re at risk of dissolving before they crystallize. The team found that crystallization rates vary significantly across species. For instance, the freshly added CaCO3 crystallizes more quickly, and therefore remains soluble for a shorter time, in Stylophora pistillata, a species known to be less vulnerable to ocean acidification.

The authors acknowledge funding from the U.S. Department of Energy, U.S. National Science Foundation and the European Research Council.