This is Eileen Wray-McCann for Circle of Blue. And this is What’s Up with Water, your “need-to-know news” of the world’s water, made possible by support from people like you.
In the United States, federal researchers expect the size of the annual low-oxygen dead zone in the Gulf of Mexico to be above the long-term average but smaller than last year. There’s a similar forecast for Lake Erie, where the annual harmful algal bloom is expected to be less severe than last year. Both the Gulf of Mexico and Lake Erie have polluted coastal waters that are caused by an influx of nutrients in the spring and early summer. Rivers carry nutrients such as nitrate and phosphorus which wash into them, mostly from farm fields. The Gulf dead zone is tied to fluctuations in the Mississippi River and it is fatal to fish and marine life. The Lake Erie algal bloom is linked with the Maumee watershed and the bloom is a toxic threat to communities that draw their drinking water from Lake Erie.
In New Jersey, state regulators formally adopted some of the strictest drinking water standards in the nation for two of the so-called “forever chemicals.” The new limits are 14 parts per trillion for PFOA and 13 parts per trillion for PFOS. The two chemicals are among the more than 3,000 compounds known as forever chemicals because they do not break down in the environment. These chemicals are used in flame retardants, nonstick surfaces, and water-repellent clothing. They are linked to cancer, liver disease, and developmental defects. Under the new rule, all public water systems in New Jersey must begin testing for the two chemicals in the first quarter of 2021. Beginning December of 2021, certain private wells must also be tested. That includes testing before a home is sold and periodic testing for rental properties that are served by a well. National standards for PFOA and PFOS are in development, but the U.S. Environmental Protection Agency says that the rulemaking process will take at least two years.
In Brazil, the government of São Paulo state announced that residents would not have their water, electricity, or gas turned off during the coronavirus pandemic if they cannot afford to pay their bills. The shutoff moratorium extends through July 31, according to Reuters news service. Water access for handwashing is considered an important defense against the coronavirus. Brazil is now the epicenter of the pandemic, registering more new cases each day than any other country. Its total case count of nearly 615,000 is second only to the United States.
This week, Circle of Blue reports on sewage surveillance as a way to monitor the new coronavirus. It’s attracting a lot of attention, but has some obstacles to overcome before it is widely used for public health decisions.
In hundreds of cities worldwide, health departments and researchers are turning to sewage to better understand the spread of the virus in their communities. This is possible because people infected with SARS-CoV-2 shed particles of the virus in their stool. Generally these are non-infectious strands of genetic material rather than active viruses, but the information is useful nonetheless.
Advocates for sewage surveillance hope that data gleaned from the sewers could serve as an early-warning system for outbreaks — a system that would perceive community spread of the virus well before cities reached the crisis levels experienced in February and March. In places like the United States where testing of residents has lagged, a central sampling point has the added appeal of simplicity, compared to the rigors of clinical testing. Why jab thousands of people per day with nasal swabs if sewage holds the same answers?
Jay Garland is a U.S. Environmental Protection Agency scientist. He said that sewage could give a broad perspective for public-health decisions about shutdowns and re-openings. In effect, he said, sewage testing could be a community swab. Sewage data has been used in the past to track polio viruses and assess illegal drug use. But for all its benefits, there are still many hurdles before sewage surveillance can be scaled up to meet the coronavirus pandemic.
Among the scores of facilities that are doing testing, there are a number of different analytical and sampling methods. The hodgepodge complicates comparison of results. In the journal Science of the Total Environment, a group of leading wastewater scientists argued for standardizing protocols. And sewage surveillance is a complicated business. Garland noted that the dynamics within sewers need to be taken into account. How do the virus particles behave within the pipes? How long do they take to degrade? What about the effect of stormwater flows and seepage? Do they mask virus particles that would otherwise be visible?
Other obstacles are in the translation of the results. Vincent Hill is with the U.S. Centers for Disease Control and Prevention. Like other health experts, he says the key issue is reliability. Public officials make serious choices about opening buildings and mandating quarantines. For that reason, says Hill, they need to be confident that sewage data is telling them something that reflects reality. Ideally, scientists would be able to measure virus concentrations in sewage and translate that into a number representing its prevalence within a community.
The science supporting SARS-CoV-2 surveillance in sewage is developing rapidly, but it is not to that point yet. Krista Wigginton, an associate professor of environmental engineering at the University of Michigan, says there’s quite a bit of work until that is a possibility. Wigginton added that there are testing refinements: samples could be taken not only from the treatment plant, but also from various points within the sewer network. Samples divided by neighborhoods could point to a variation within a city. These neighborhood samples could then be matched with clinical data to validate the findings. Wigginton was awarded a National Science Foundation grant in March to investigate the coronavirus. She is tracking sewage from 25 utilities in California.
Interest in sewage surveillance is high and growing. Biobot, a Boston-area startup, is testing sewage from about 400 facilities in 42 U.S. states. Researchers and public health authorities in the Netherlands are analyzing sewage from more than two dozen cities in that country. A team from Syracuse University is investigating sewage in Onondaga and Cayuga counties, in New York. An international research collective is using the networking tool Slack to collaborate. Its website notes sewage surveillance studies from nine countries.
Garland of the EPA said the agency is working with the state of Ohio to develop a pilot testing program. He said that Gov. Mike DeWine wants to implement such a program statewide. Other states are waiting. Kristen Maki, speaking for the Washington State Department of Health, says it is aware of the sewage surveillance methods but does not have any plans to use them at this time. She said that her department’s priority is controlling the virus in order to reopen the economy, and that it was focusing on testing, contact tracing and health system support. Scaling up sewage testing by adding more locations and increasing the frequency of sampling will require more resources than are currently available.
But even relatively small investments could be worthwhile, argues David Sedlak. He’s an environmental engineer at the University of California, Berkeley. He said “When you think on the scale of shutting down cities, spending tens of millions of dollars might be sensible.”
And that’s What’s Up With Water from Circle of Blue, which relies on your support for independent water news and analysis. Please visit circleofblue.org
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