Transcript

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, rising seas around San Francisco are threatening billions of dollars of commercial property and transportation infrastructure, as well as housing for tens of thousands of low-income residents, and habitat for endangered species. That’s according to the first comprehensive regional evaluation of the impact of sea-level rise on the nine counties that ring San Francisco Bay.
The report says that one of the country’s most populated metropolitan areas is nearing a tipping point. The bay is beginning to see irreversible damage from rising waters. However, the knowledge and tools for adaptation and response are available for use.
The report focused on risks to four key areas: transportation infrastructure, vulnerable communities, ecosystems, and lands targeted for future urban growth. The study identified 18 hot spots along the bay. Hot spots are highly vulnerable in several of the key areas. The analysis was informed by 10 sea-level rise scenarios. At the low end is a 1-foot increase above the current high-tide line by the year 2100. At the high end is a 9-foot rise, which represents an extreme scenario.
The result of the study is an expansive picture of flood risks in this century, but it does not cover everything. Factors that were not included in the analysis include groundwater, which rises in tandem with the bay, and flooding from rainfall and urban runoff.
The report says that adapting to these changes will require strong partnerships across political jurisdictions and between government agencies. The report was prepared by the Bay Conservation and Development Commission, a state regulatory body. Partners in the project included regional and state agencies.
In Australia, the government of New South Wales approved the expansion of longwall coal mining beneath a drinking water reservoir in the Sydney metropolitan area. Such a decision has not been made in two decades.
Longwall mining is a mining technique that cuts away long, continuous seams of coal. Some longwall mines extend horizontally two miles or more underground. After each segment in the seam is removed, the roof above that segment is allowed to collapse. This disruption of the earth below can damage structures on the land above and alter the flow of water.
The Sydney Morning Herald reports that the New South Wales Planning Department will allow the coal company Peabody Energy to develop three new longwall mines. Two of the mines will tunnel beneath Woronora reservoir. Scientists warned about the potential long-term effects on the water catchment. Peter Turner of the National Parks Association said that cracks in the ground could cause the reservoir to leak, and there is no reliable way to measure reservoir leakage caused by longwall mines.
In Mexico, roughly 36,000 residents in the border town of Mexicali voted on the fate of a large brewery being constructed by the U.S.-based Constellation Brands. About three-quarters of voters called for the project to be cancelled. Residents worry that the water demands for the $1 billion brewery would have worsened water scarcity in an already dry region. Constellation Brands accepted the decision last week, according to Reuters news service. Mexico’s president said government officials were in discussions with the company about potential new sites for the brewery but Constellation representatives would not provide details about the talks.
This week Circle of Blue reports on the virus detectives who are studying urban sewage for clues to the spread of the coronovirus. 
Even before medical tests of infected residents confirmed it, the story of the new coronavirus in the city of Amersfoort was being recorded in water. Scientists from KWR Water Research Institute in the Netherlands detected genetic traces of the SARS-CoV-2 virus in wastewater samples from Amersfoort’s sewage treatment plant on March 5, a day before the first confirmed case of Covid-19 in the city. Covid-19 is the disease caused by the virus. That discovery, the researchers say, means that urban sewage systems could act as “a sensitive tool” for monitoring the spread of the virus thorough a city before it is detected in individuals. Similar sewage-sleuthing methods have been used to detect polioviruses or to assess illegal drug use.
How sensitive a tool? The study, which was published online before peer review, looked at wastewater samples from seven cities in the Netherlands and from Amsterdam’s Schiphol Airport. Samples taken in the first week of February did not reveal any trace of the virus, but in the second round of sampling, on March 4 and 5, samples from four wastewater plants showed evidence. At the time, there were only 82 confirmed cases in a country of 17 million people. A rough estimate — based on the observed number of confirmed cases in the cities — is that a virus signal starts to show up in wastewater when between one and four people per 100,000 are infected. The range depends on the virus protein that was analyzed.
Zhugen Yang specializes in biomedical diagnostics at the Cranfield Water Science Institute in the United Kingdom. He said that an early-warning system with this level of acuity could provide government authorities with useful data about the potential for infection. It is especially difficult, for instance, to track the prevalence of cases in which infected people show only mild symptoms and thus do not get tested.
Yang told Circle of Blue “If the sewage test comes back negative, there could be confidence that there is less risk of infection.”
Other organizations are jumping into sewage tracking, a scientific field also known as wastewater epidemiology.
In the United States, the leading group is Biobot, a Boston-based startup founded in 2017. The tech firm is partnering with researchers at MIT, Harvard, and Brigham and Women’s Hospital to test wastewater samples for SARS-CoV-2 and incorporate the data into forecast models. The data could make the models more accurate and potentially provide a real-time map of infection across the country.
Biobot’s call for samples has been so successful since it opened enrollment on March 17 that the company is at capacity and working hard to scale up, according to Mariana Matus, the company CEO and founder. Matus told Circle of Blue that she launched the campaign with a goal of getting 100 utilities to participate. Within two weeks, she said, the campaign “was already oversubscribed,” having fielded more than 130 requests from nearly every state.
There are drawbacks to lab-based approaches. For Biobot, testing kits are sent to participating utilities, water samples are collected over a 24-hour period, and then returned to Biobot for laboratory testing. It’s a cumbersome process that requires sophisticated analytical equipment and time  — an estimated three days once the sample is collected. Yang, who is a water sensor specialist, would like to see broader use of portable paper-based tests. These devices, like a litmus test in concept but significantly more complex in practice, reduce the time and cost of testing. Yang has already used them to evaluate malaria in Uganda, but he said that it would take a lot more to develop a SARS-CoV-2 paper-based test from a lab concept to field use.
Knowledge about SARS-CoV-2, just a few months into the outbreak, is limited but growing rapidly. Initial findings were connected to the behavior of other coronavirus, such as the closely related virus responsible for the 2003 SARS outbreak.
Finding genetic traces in feces does not mean that those viral remnants are able to reproduce and cause additional infections. Disinfection, either with chlorine or ultraviolet light, kills the virus, so it is not expected to be present after sewage is treated. SARS-CoV-2 belongs to a class of viruses known as enveloped viruses, a category named for the fatty coat that protects the inner genetic material. Disinfection has been shown to be particularly effective on enveloped viruses. At this point, treated sewage does not seem to be a significant source of Covid-19 transmission, but the research field is moving quickly and looking into the virus’s ability to survive in raw sewage. Researchers in China were able to isolate a live virus from the feces of two Covid-19 patients. What that means for potential disease transmission is still being assessed.
And that’s What’s Up With Water from Circle of Blue, which depends on your support for independent water news and analysis. Please visit circleofblue.org and make a difference through your tax-deductible donation.