N.B. wastewater data suggests some COVID-19 cases went undetected in 2021

Thu, July 14, 2022

Gen Erjavec conducts COVID-19 wastewater monitoring outside Risley Hall, a residence at Dalhousie University. The City of Moncton has been doing its own COVID-19 wastewater testing in partnership with Dalhousie University since fall 2020. (Submitted by Graham Gagnon - image credit)

Public Health officials have raised questions around whether some COVID-19 cases in New Brunswick went undetected in early 2021, after an apparent mismatch between the amount of COVID-19 appearing in wastewater and the province's own COVID-19 testing.

The wastewater data shows four apparent spikes of COVID-19 in 2021: on Feb. 8, March 18, April 29 and June 28, all times when there were "minimal cases or positive tests" reported and PCR testing was widely offered.

The wastewater testing is conducted by the City of Moncton, which has a partnership with Dalhousie University, and is provided to New Brunswick Public Health. CBC News obtained a copy of the test results, and discussion within the Department of Health about the results, through access to information.

Emails from this past April show health officials tried to find an explanation for the differences in the 2021 data, such as increased occupancy at hotels around March break, a difference in the boundaries between the health zone and the area covered by the wastewater treatment plant, and the role of temporary foreign workers who were quarantining in local hotels.

But they couldn't find an easy answer.

'Things do not seem to be lining up'

"The points that you have mentioned are all things that we have considered, but things do not seem to be lining up," Shannon LeBlanc, the manager of surveillance for the Department of Health, wrote in an April 7, 2022 email.

"We have taken into accounts cases in areas outside of Moncton, and cases among the temporary foreign worker population. It is possible that we had cases that went undetected (how many is not clear)."

Duk Han Lee/CBC News Graphics

No one from Public Health was made available for an interview to explain the apparent mismatch.

In an emailed statement, Department of Health spokesperson Valerie Kilfoil said the government is still assessing the benefits of the wastewater testing pilot in Moncton.

"The materials provided to you should be considered working documents – not a formal surveillance program by the province," Kilfoil wrote.

She didn't provide any explanation about why the data seemed to show some cases of COVID-19 went undetected.

Raywat Deonandan said the province shouldn't dismiss the wastewater results.

"It is so objective, more so than PCR testing, that I think we have to hang our hats on it more confidently," said Deonandan, who is an epidemiologist and associate professor in the faculty of health sciences at the University of Ottawa.

Without widespread random testing, which can capture people who are asymptomatic, Deonandan said it's common to under-detect COVID-19 cases.

"If random testing is not being done, as it isn't anywhere frankly, the PCR testing is not a good indication of the true extent of disease burden," Deonandan said.

"That's why I would err on the side of wastewater data to get a true sense of prevalence, not on PCR testing data."

Most provinces in Canada aren't detecting the full scope of COVID-19 infections because there's not enough testing being done, according to Tara Moriarty, an associate professor and infectious disease researcher at the University of Toronto.

New Brunswick offered widespread PCR testing in early 2021, but PCR tests are now only available to people over age 50 or under age two, people who are pregnant or immunocompromised, or people who work in a vulnerable setting, such as a hospital.

"We tend to prioritize testing for people who are higher risk," Moriarty said.

"So that means that we sometimes do have quite a few more infections than we think, as would be suggested by wastewater data. But we're simply not capturing them because we're not testing enough."

Kilfoil said the province is "no longer seeking to confirm and detect every single case occurring in the province or within specific communities."

Province considering COVID-19 wastewater monitoring

Dalhousie University's Centre for Water Resources Studies has been measuring COVID-19 in wastewater in partnership with the City of Moncton for about 18 months, according to Graham Gagnon, the centre's director.

He said it's not surprising to see a mismatch between the wastewater data and public health's testing data. The two bodies aren't coordinating when collecting their data, so there could be differences in how they're collecting information and reporting it.

CBC

"For the wastewater work that we've done in Nova Scotia and New Brunswick, it's been a research scheme, not a public health reporting mechanism," Gagnon said.

"As a result, it was never intended to be coordinated, so you end up with gaps from a wastewater standpoint."

Last month, Chief Medical Officer of Health Dr. Jennifer Russell said the province is considering implementing COVID-19 wastewater monitoring, but didn't provide any details on who will conduct the testing and whether it will sample the entire province or just certain centres.

Other jurisdictions, such as Ottawa Public Health, post results of their COVID-19 wastewater data online. The federal government also has a COVID-19 wastewater surveillance dashboard, but it doesn't include data from New Brunswick.

Deonandan, the epidemiologist, sees value in sharing wastewater testing data with the public.

"This is the kind of thing that should be made publicly available, because we're in an era now where there's so much distrust of authority, that the only way forward is maximum transparency at all times."

Capturing the impact of human sewage on Earth’s coastal ecosystems

New worldwide mapping analysis identifies key exposure hotspots in unprecedented resolution

Peer-Reviewed Publication

PLOS

 

IMAGE: A) GLOBAL MAP OF THE TERRESTRIAL SOURCES (GREEN TO BLUE) AND COASTAL DIFFUSION OF INPUTS (YELLOW TO PURPLE) OF TOTAL WASTEWATER N, MEASURED IN LOG10(GN) IN BOTH. COASTAL PLUMES HAVE BEEN BUFFERED TO LINE SEGMENTS TO EXAGGERATE PATTERNS TO BE VISIBLE AT THE GLOBAL SCALE. INSETS SHOW ZOOMED-IN VIEWS OF THE B) GANGES, C) DANUBE, AND D) CHANG JIANG (YANGTZE) RIVERS, SHOWING WASTEWATER PLUMES AT HIGH RESOLUTION. view more 

CREDIT: TUHOLSKE ET AL., 2021, PLOS ONE, CC-BY 4.0 (HTTPS://CREATIVECOMMONS.ORG/LICENSES/BY/4.0/)

A first-of-its-kind, high-resolution mapping analysis estimates the amounts of nitrogen and pathogens released into coastal ecosystems from human wastewater sources around the world. Cascade Tuholske (now affiliated with the Columbia Climate School) and colleagues at the University of California, Santa Barbara, present this research in the open-access journal PLOS ONE on November 10, 2021. The researchers have created a visual representation of this, available here.

Human sewage can introduce disease-causing pathogens and nitrogen into the ocean, potentially impacting human health as well as coastal ecosystems and the communities that depend on them for such purposes as fishing. However, most research into humans’ impact on coastal ecosystems has focused on agricultural runoff, while investigations on human sewage have been limited.

To better capture the impact of sewage on coastal ecosystems, Tuholske and colleagues conducted a novel analysis in which they estimated and mapped nitrogen and pathogen inputs into the ocean from sewage for about 135,000 watersheds around the world at a resolution of 1 kilometer. The assessment employed newly available, high-resolution data on global human populations and modeled how wastewater plumes entering the ocean would overlap with different ecosystems.

The analysis suggests that wastewater from human sewage introduces 6.2 teragrams of nitrogen into coastal ecosystems per year—for comparison, that is about 40 percent of estimated inputs from agriculture. Sixty-three percent of the nitrogen is from sewage systems, 5 percent from septic systems, and 32 percent from untreated, direct input.

Of the watersheds that appear to release the most nitrogen from sewage, most are located in India, Korea, and China, with the Chang Jiang (Yangtze) River contributing 11 percent of the global total. The researchers also identified hotspots for coral reef exposure to nitrogen in China, Kenya, Haiti, India, and Yemen. Seagrass exposure hotspots were found in Ghana, Kuwait, India, Nigeria, and China. The Chang Jiang and Brahmaputra Rivers have the highest input of pathogens.

Further research will be needed to refine the model and its estimates. Nonetheless, this work provides a new resource that could play a key role in efforts to mitigate harm to ecosystems and human health—such as by highlighting locations where tradeoffs between managing nitrogen and pathogen levels are particularly important to consider.

The authors add: "The sheer scale of how much wastewater is impacting coastal ecosystems worldwide is staggering. But because we map wastewater inputs to the ocean across more than 130,000 watersheds, our results identify target priority areas to help marine conservation groups and public health officials to work together and reduce the impacts of wastewater on coastal waters across the planet."  

CAPTION

The global total wastewater input is 6.2Tg N, with 3.9Tg from sewers, 0.3Tg from septic, and 2Tg from direct input. The top 40 countries are shown in the horizontal bar chart; remaining countries are in the pinwheel, grouped by continent or larger geographical region. Values for all countries are also reported in S5 Table in S1 File. Note that the Netherlands is shown in both places (in red) to help connect the scale of the two parts of the figure.

---

 

CAPTION

Maps show where A) coral reefs and B) seagrass beds are heavily impacted (raster cells in top 2.5% of exposure; red dots), not impacted (no exposure to wastewater N; dark blue dots), or impacted but not in the top 2.5% (yellow dots). Raster cells are represented as points which visually over-represents the habitat; red is overlaid on top which makes it visually dominant; blue points are transparent and overlaid on green/yellow points such that higher densities of unimpacted areas are brighter blue.

10.1371/journal.pone.0258898 

METHOD OF RESEARCH

Computational simulation/modeling

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Mapping global inputs and impacts from of human sewage in coastal ecosystems

ARTICLE PUBLICATION DATE

10-Nov-2021

COI STATEMENT

The authors have declared that no competing interests exist.

What’s in the water?

Researchers take a granular look at global inputs and impacts of human wastewater in coastal ecosystems

Peer-Reviewed Publication

UNIVERSITY OF CALIFORNIA - SANTA BARBARA

 

IMAGE: EXCESS NITROGEN AND OTHER NUTRIENTS CONTRIBUTE TO HARMFUL ALGAL BLOOMS view more 

CREDIT: NICHOLAS AUMEN/UCGS

The tendency for most of us when it comes to human wastewater is out of sight, out of mind. Rarely do we consider what happens after we flush that toilet or turn off that tap.

However, researchers at UC Santa Barbara have turned their attention and considerable computational power to the subject and its impacts on global coastal ecosystems. The results aren’t pretty, but they are enlightening.

“The motivation behind this research was a desire to have a fine-grain understanding of how wastewater is impacting coastal waters worldwide,” said Cascade Tuholske, the lead author of a paper that appears in the journal PLOS One. While research on terrestrial threats to coastal marine ecosystems often focuses on agricultural runoff and what happens when fertilizer and livestock waste winds up in the ocean, he said, few studies investigate what happens when human sewage does the same.

“This isn’t the first study to produce a global wastewater model, but it is the first study to map the inputs of nitrogen and pathogens from wastewater across 130,000 watersheds across the planet,” Tuholske said. “And this is important because there are trade-offs in the intervention space.” Information from this model, he added, could make those trade-offs clearer and management decisions easier to make.

The Scale of the Problem
The majority of human wastewater is discharged into the ocean around the world in a variety of treated and untreated states from sewage, septic and direct input sources. Not surprisingly, major human wastewater sources are also places with dense human populations, which tend to aggregate around major watersheds.

“We estimate that 25 watersheds contribute approximately 46% of global nitrogen inputs from wastewater into the ocean,” said Tuholske, a postdoctoral researcher at Columbia University who conducted this study as a graduate student at UC Santa Barbara. “Nearly half as much nitrogen comes from wastewater as agricultural runoff globally,” he added, “which is a huge fraction.” Coastlines all around the world are affected by increased nitrogen, according to the paper.

Tuholske and an interdisciplinary group of fellow UCSB scientists — Ben Halpern, Gordon Blasco, Juan Carlos Villasenor, Melanie Frazier and Kelly Caylor — have created a data visualization that maps globally the sources and destinations of nitrogen, a common element in both agricultural and human wastewater that causes eutrophication. It’s a phenomenon in which excessive nutrients create phytoplankton blooms just offshore that produce toxins and deprive the waters in the area of oxygen. These so-called “dead zones” not only suffocate the sea life unfortunate enough to be trapped in them, but also can cause problems in the food chain, including for humans.

“Many coastal ecosystems, such as coral reefs and seagrass beds, are particularly sensitive to excess nutrients, even if you don’t have a dead zone,” said Halpern, a professor in the Bren School of Environmental Science & Management and the director of the National Center for Ecological Analysis & Synthesis at UCSB. “The whole ecosystem can tip into a highly degraded state when nutrient levels are too high. Coral reefs can be converted into fields of algae that overgrow and kill the corals below them. Our work here helps map where nutrients from wastewater are likely putting these ecosystems at greatest risk.”

For Tuholske, whose research focuses on food systems, the model puts into stark relief the impact of modern diets on coastal ecosystems.

“What was really surprising through this research is how diets shifting to animal-based proteins are impacting marine ecology,” he said. As countries get wealthier and incorporate more meat into their food systems, he explained, the more nitrogen shows up in the wastewater, in addition to the already high levels generated by agriculture.

“The more burgers people are eating, the more nitrogen is getting into the ocean,” he said.

Two Targets
Excessive nitrogen isn’t the only concern with the growing amount of human wastewater being discharged into the ocean; where wastewater goes, so too go pathogens. But the removal of nitrogen or pathogens can require very different methods, which can make it difficult for decisionmakers with finite resources and varying priorities to weigh their options between improving public health and protecting coastal ecosystems.

With the fine-scale estimates of nutrient and pathogen inputs provided by this model, the aim is to provide information that can lead to local solutions that together can tackle a complex global problem.

“These top-down, fine resolution hotspot maps can be matched with bottom-up approaches, and we can transfer knowledge across geographies,” Tuholske said. “Adaptation and mitigation really come from the bottom up, and having a global map helps to target priorities and share knowledge.

“While we map the scale of this problem, we can do something about it,” he added. “We can protect both public health and coastal ecosystems.”

###

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JOURNAL

PLoS ONE

 State officials not planning to test wastewater in New Mexico for avian flu

IRRESPONSIBLE & LAZY

Danielle Prokop
Thu, May 16, 2024 

An aeration basin at the Southside Water Reclamation Plant in Albuquerque. A CDC contractor tested for the presence of COVID-19 at this and four other sewer systems in New Mexico. New Mexico health officials say there are no plans at this time to test for avian flu in wastewater.

 (Courtesy Albuquerque Bernalillo County Water Utility Authority)

Experts around the country have called on federal officials to use wastewater testing for the avian influenza strain H5N1, which has broken out in more than 33 dairies across eight states, including New Mexico.

While there are only two documented cases of viral crossover to humans documented in the U.S. since 2022, scientists said that wastewater testing is a crucial tool in watching for emerging threats to public health, including avian flu.

Marc Johnson, a virologist at the University of Missouri, developed a probe to track avian flu in wastewater over a year ago, as he was concerned about avian flu spread in U.S. birds in 2022.

“What wastewater does is gives you an unbiased readout of a community. It will tell you what is circulating, whether it’s showing up in the clinic or not,” he said.

Testing for virus material in wastewater is often cheaper than commercial tests, because states are already collecting the samples, and it just means adding an additional test. He said the federal government or other health agencies could implement a probe and test for H5N1 in sewage. The fact that it has spread so widely in cows before, is cause for concern.

“I just want to know where we’re at. I am astounded that this got this far, and no one noticed,” Johnson said.

The H5N1 probe is currently not being used in his job, which includes wastewater surveillance for SARC-coV-2 and other influenza strains in wastewater in Missouri.

Instead, many communities are using flu probes, which would pick up all variants of Influenza A, including the specific avian flu strain H5N1. But that means even if detected, avian flu would be indistinguishable from other strains.

Without more specific testing, health officials “don’t know whether the signal was actually H5N1 or something else,” Johnson explained.

There’s a need to know how widespread avian influenza is, he said, and the current plan isn’t cutting it.

“Since we’ve already demonstrated our lack of ability to track this lineage using our standard surveillance, it seems prudent to expand the other types of surveillance,” Johnson said.

New Mexico health officials have no plans to implement further wastewater testing for H5N1, said State Public Health Veterinarian Erin Phipps with the Department of Health.

New Mexico has not been asked to be involved in any wastewater-testing plans for avian flu at this point, Phipps said, “although I am aware of many conversations happening amongst many different entities about wastewater.”

There is no standardized probe for avian flu, yet. Researchers from Baylor College of Medicine and University of Texas Health Sciences Center published preliminary findings using their own probe last week. They found H5N1 in wastewater samples from nine Texas cities.

“A variant analysis suggests avian or bovine origin but other potential sources, especially humans, could not be excluded,” the study stated. The data still needs peer-review.

Johnson, who is not involved with the Texas study, said there’s still more to learn from testing for the avian flu in wastewater.

“Most sewersheds in the United States are closed, and you don’t get a lot of wild bird feces in the sewage. But the concern that probes are detecting milk that’s been poured down the drain, or dairy byproducts, is legitimate,” he said. “You won’t know whether it’s circulating in humans or not just from wastewater.”

After several days’ delay, the Centers for Disease Control and Prevention launched a dashboard Tuesday, showing national wastewater data for Influenza A, since the past two weeks have shown higher levels of Influenza A in wastewater.

The data can’t tell us specifically how much of that is caused by the bird flu strain H5N1, which is currently indistinguishable from other types of Influenza A.

New Mexico has insufficient data to make any determination on Influenza A levels, according to the dashboard.
Protections for workers

The state has set up additional personal protective equipment for farmworkers in Curry County — where eight herds were confirmed to have been infected by avian flu — as well as in public health offices and the New Mexico State University Extension Office.

Local offices in Curry and Roosevelt counties were also supplied with tests for workers, as well as antiviral treatments for any positive cases.

Anyone who’s been exposed or had contact with an animal that is suspected or confirmed to have avian flu and has symptoms could be tested quickly, Phipps said.

While risk to the general public is still low, she said, people who come in close contact with birds or cows have a higher risk. If experiencing cold or flu-like symptoms and conjunctivitis — that’s a reddening of eyes — they can reach the department, she said, and test for avian flu.

COVID-19 wastewater testing proves effective in new study

Research offers much-needed guidance for early detection in nursing homes, dorms, barracks

UNIVERSITY OF VIRGINIA HEALTH SYSTEM

Research News

 

IMAGE: UVA HEALTH'S AMY MATHERS, MD, LED A STUDY TO DETERMINE THE STRENGTHS AND LIMITATIONS OF WASTEWATER TESTING TO DETECT COVID-19 IN DORMS, NURSING HOMES, PRISONS AND OTHER CONGREGATE SETTINGS.... view more 

CREDIT: SANJAY SUCHAK | UVA COMMUNICATIONS

Wastewater testing is an effective way to identify new cases of COVID-19 in nursing homes and other congregate living settings, and it may be particularly useful for preventing outbreaks in college dormitories, a new University of Virginia study finds.

The research, a collaboration of UVA's School of Medicine and School of Engineering, was led by UVA Health's Amy Mathers, MD. It offers some of the first clear guidance on the most effective methods to perform testing to detect COVID-19 in wastewater.

The researchers evaluated and compared sampling and analysis techniques by testing them within buildings with known numbers of positive cases. They were then able to determine wastewater testing's strengths and limitations as a tool for monitoring COVID-19 in a building population. For example, the technique proved better at detecting initial infections than determining the number of occupants infected or how long they had been infected.

One important answer revealed by the research: Wastewater testing can detect even small numbers of asymptomatic cases, something not previously documented.

"This work could be applied to surveillance in buildings where people live in groups, where transmission may be hard to control but the risk of spread could be high," said Mathers, an infectious disease expert in the School of Medicine's Department of Pathology. "Since we can identify new infections with high sensitivity, it provides an early warning signal of when to test everyone in the building to find and isolate the newly infected persons before an outbreak becomes large."

Wastewater Testing for COVID-19

To evaluate the effectiveness of wastewater testing for detecting COVID-19, Mathers collaborated with Lisa Colosi-Peterson, PhD, an associate professor in UVA Engineering's Department of Engineering Systems and Environment, who connected with Mathers through UVA's Center for Engineering in Medicine. They and their colleagues monitored wastewater from two student dormitory complexes for eight weeks. The researchers found that the wastewater testing caught more than 96% of cases.

One limitation of wastewater testing: It could not distinguish between new infections and virus found in stool from those who had recovered and were no longer contagious. That means the wastewater testing detected both active and former cases. "The inability to distinguish recently infected but no longer contagious persons from new contagious infections within a building is an important finding, as it means that wastewater testing would be best for identifying new cases and isolating individuals in groups without recent infections," Mathers said.

UVA's new research also establishes useful protocols for wastewater testing. In a scientific paper outlining their findings, the researchers describe how they collected and tested the samples, noting that refrigerating the samples on ice adequately preserved them for testing that same day. Institutions that plan to send their samples elsewhere for testing, however, may need to take additional steps to preserve the samples for longer, the researchers note. Cleansers and disinfectants used in the facilities could also degrade the viral RNA over time, they caution.

While the researchers are urging further study, they conclude that wastewater testing holds great promise for detecting and controlling COVID-19 in places where people live in close quarters. "Passive pooled surveillance of wastewater is now serving as an early warning system in many dormitories, barracks and prisons to identify new cases in situations where transmission risk is high," Mathers said. "Applications for wastewater surveillance to inform and control infectious disease transmission will continue to evolve, but it is hard to believe how far and how fast we have come in the last year."

###

Findings Published

The project was a collaborative effort of UVA's School of Medicine, School of Engineering, School of Data Science and UVA Health's Facilities Management. The research team consisted of Colosi-Peterson, Katie E. Barry, Shireen M. Kotay, Michael D. Porter, Melinda D. Poulter, Cameron Ratliff, William Simmons, Limor I. Steinberg, D. Derek Wilson, Rena Morse, Paul Zmick and Mathers.

The researchers have published their findings in the scientific journal Applied and Environmental Microbiology.

The work was supported by a UVA Engineering in Medicine Seed Grant and support from the University Reopening Committee.

To keep up with the latest medical research news from UVA, subscribe to the Making of Medicine blog at http://makingofmedicine.virginia.edu.

The secrets hidden in sewage

Wastewater can help us monitor Covid-19. 

What else can it tell us?

By Dylan Scott@dylanlscottdylan.scott@vox.com Apr 13, 2022, 

The potential for human waste to tell us about what is happening with our community’s health extends far beyond Covid-19. Getty Images/EyeEm

The first signs of the most recent Covid-19 waves have often been detected in our sewers instead of nasal swabs.

But in the future, the potential for human waste to tell us about what is happening with our community’s health could extend far beyond the novel coronavirus.

“This has been its coming-out party. We’ve realized the power in this pandemic,” John Dennehy, a biologist at the City University of New York who has been assisting with NYC’s wastewater surveillance program, told me. “Now there’s great interest in developing an infrastructure to sustain this capability beyond the pandemic.”

Sewage surveillance is becoming more valuable right now as conventional testing is becoming less transparent. More people have been using rapid at-home tests and might not report results to a public health agency. That means the number of positive cases being reported by official sources might not actually provide a full picture of what’s happening with the pandemic.

But no matter how or if they’re testing, infected people — whether they have symptoms or not — flush out the virus when they go to the bathroom, leaving viral RNA that can be detected in wastewater samples. It requires careful collection and testing, but sewage can provide a less biased look at the viral trends in a given community.

Science has not yet reached the point where we can say that X amount of viral load in a community’s sewage means Y number of people are infected in that community. But still, knowing which way viral loads are trending is useful. If they are going up, even before the number of positive tests starts increasing, it could in theory allow public health authorities and the local health system to start preparing for a surge. If they are going down, public health officials (and the general public) can be confident that any waning in official case numbers is real and not the byproduct of, say, less testing.

So far, health authorities have not been using wastewater levels to trigger a public health response — ordering people to mask up again once viral loads hit a certain level, for example. But experts say a more direct link between sewage surveillance and public health policies might be established in some places in the coming year.
Covid-19 has shown the value of public health sewage surveillance

The pandemic has revealed the potential for wastewater surveillance — and the shortcomings in the current US infrastructure.

Dennehy told me that his team in NYC had noticed an unusual iteration of the virus back in November, but it wasn’t until South Africa announced the presence of the omicron variant in people there a month later that they realized they had been seeing the mutations that would soon start a new wave of infections worldwide.

South Africa has been commended for its genomic surveillance system, which is what allowed it to be the first to identify omicron as a threat, even though, as the New York example shows, the variant was likely already present in other parts of the world. The US, on the other hand, lagged behind other countries for much of the pandemic in that work, and integrating sewage into that surveillance system remains a work in progress.

Before the pandemic, using wastewater for disease surveillance was not unheard of, but it was generally limited to monitoring for diseases like polio, where the appearance of any amount of virus would be cause for alarm.

Covid-19 has shown that wastewater can provide an even more nuanced and varied picture of a community’s health. Since researchers showed the ability to detect the coronavirus in sewage in early 2020, wastewater surveillance has spread across the globe. More than 470 sites in the US and nearly 3,400 sites worldwide are reporting the amount of virus they are detecting in the waste we flush.

Wastewater has its limitations, including challenges with proper collection and adjusting for the concentration of human waste in the sewage. Some rural areas don’t have a community wastewater system, relying instead on individual homes’ septic tanks, which makes broad monitoring impossible. Across Montana, Wyoming, North and South Dakota, and Nebraska, only two wastewater sites are reporting their coronavirus levels to the CDC.

Setting up a strong wastewater monitoring program also requires political support and coordination between public health departments, environmental agencies, and local water authorities, which may not be accustomed to working together.

In spite of those obstacles, sewage monitoring has become more integrated into the global pandemic response over time. And experts don’t expect it to stop there. They are already imagining how else we might use all the information that can be gleaned from our waste to get ahead of future outbreaks and target public health interventions.

“Most people believe wastewater testing is not going away,” Marc Johnson, a University of Missouri virologist who has helped lead that state’s wastewater monitoring program, told me. “It’s too nice of a tool. It can give us an unbiased readout of a community’s health, without having to worry about individual patient confidentiality.”
All the ways wastewater surveillance could help us improve public health

For the foreseeable future, sewage surveillance could help the country keep ahead of Covid-19. Not only can the general trends — an increasing or decreasing amount of virus being found — give a warning about emerging or fading waves, but wastewater can also provide scientists clues about new variants that may soon appear.

After wastewater is collected and taken to a laboratory, scientists run the same kind of test that is conducted for an individual diagnostic PCR test. Beyond identifying whether or not the virus is present, the lab can also determine how much of it there is depending on how many testing cycles they need to run to detect it. (Fewer cycles means more virus.)

Then scientists can also take the sample and analyze the genetic make-up of the virus found therein. If it’s different from the most common variant at the time, that may be a signal that another variant is lurking out there with the potential to take over. Johnson said that, in Missouri, his team has seen Covid-19 variants that have not been detected in humans yet. They may have found their way into the wastewater system from animals, he told me, and we know that animal-to-human transmission is one way for new variants to emerge.

US scientists are also starting to use wastewater in more targeted ways to combat Covid-19. Dennehy said an NYC hospital had asked his team if they could start analyzing the sewage coming out of their facility specifically so they could get an early warning if the virus was appearing more frequently in their patients and staff. Continuous diagnostic testing would be expensive to maintain, and this population-level surveillance would allow the hospital to institute more rigorous testing only when the viral load in the wastewater suggests that it’s necessary.

That kind of creative approach can be applied to other public health problems as well.

Johnson described a similar proposal in Missouri prisons that want to monitor for tuberculosis outbreaks. They have asked for their sewage to be regularly tested for TB, which they could use to determine when to conduct individual diagnostic tests, which are both costly and logistically cumbersome.

“They don’t have to waste money on testing when they know there is nothing there,” he said.

Surveillance programs could watch for other pathogens, too, such as influenza, hepatitis, and norovirus for early warnings of emerging outbreaks. Julianne Nassif, an expert on wastewater surveillance with the Association of Public Health Labs, said we could also monitor for bacteria, viruses, and other microbes that are resistant to current treatments. Public health officials could try to get ahead of an outbreak of antibiotic-resistant bacteria in a nursing home, for example, with the information gleaned from downstream sewage.

Johnson envisioned communities monitoring for narcotics, to better tailor their public health campaigns. Wastewater could be tested to determine whether cocaine or opioid use is rising in a given sewage shed. It could even determine what kind of opioids are being used, which could be helpful to health departments. Widespread heroin use might require a different intervention than diverted prescription opioids or black-market fentanyl.

The possibilities sound almost endless, extending to research that could help us better understand human health. Dennehy described to me one hypothetical experiment that could be run with sewage monitoring, looking for the viral markers associated with colon cancer. By comparing the results from one community with, say, a nearby nuclear power plant and another community somewhere else, we could get a better understanding of how the surrounding environment affects people’s health.

But for all of this potential to be realized, these efforts would require sustained support. The CDC bet on the wastewater boom, launching a national Covid-19 surveillance system in the fall of 2020. But dedicated investments in infrastructure and a workforce would be necessary if the country were to begin conducting wastewater surveillance on a more permanent basis.

In general, the US has not appeared willing to make big investments in public health. Scientists working on these programs hope that the same may not be true of wastewater surveillance, given the opportunities it presents.

“We learned a lot of hard-won lessons with the Covid pandemic. We got caught with our pants down at the beginning. A lot of things that we did were too late,” Dennehy told me. “The hope is we can remember these lessons for the next time this comes around, which may not be that long.”

Why scientists say wastewater surveillance needs to continue, despite low COVID-19 levels

Story by Jennifer La Grassa • CBC -  Jul 19, 2023

Despite a majority of wastewater sites across the country reporting some of the lowest levels of COVID-19 since analysis began, some researchers say this type of surveillance should continue so Canada can be prepared for the next pandemic.

Wastewater surveillance gained prominence in recent years by providing health officials with a summary of the degree of disease among Canadians during peaks in the pandemic. But its value beyond the coronavirus was quickly realized as a crucial public health tool that could help protect people from future harmful infections.

Of the 39 sites tracked by Canada's COVID-19 wastewater surveillance dashboard, recent data shows that about 60 per cent are reporting decreasing levels of the virus. The rest of the sites are stable or slightly lower than their previous readings.

"In the past, I would say, several weeks, we've seen a relatively consistent downward trend," said Dr. Guillaume Poliquin, vice-president of the National Microbiology Laboratory, part of the Public Health Agency of Canada (PHAC).

Wastewater reporting began in 2020, not long after the pandemic was declared by the World Health Organization, with more sites added as it continued.

Even though the amount of the virus at many of PHAC's sites appears to be at its lowest point since reporting began, Poliquin said it comes with a caveat.



Dr. Guillaume Poliquin, vice-president of the Public Health Agency of Canada's National Microbiology Laboratory, says ongoing conversations are taking place and work is being done to sustain and expand the wastewater surveillance system. 

"The techniques that are used, how accurate they are, how sensitive they are, has generally been getting better over time," he said.

"Monitoring has changed over time. It's not all the time comparable, but the trend is certainly reassuring."

It became apparent during the pandemic that COVID-19 levels will fluctuate based on the time of year. Disease spread tends to be lower in the warm summer months, with one reason being that people spend more time outdoors.

At the same time, 80.5 per cent of Canadians are fully vaccinated against the virus and more than 4.6 million have been infected, according to PHAC data — although its website notes that due to changes in testing, the number of cases might actually be higher.

How important is surveillance?

The practice of gathering wastewater from different communities and analyzing it for COVID-19 is a public health tool that researchers have said is useful to predict disease trends and support decisions around public health policies. But it's also a strong indicator of what's to come, as experts can see whether a new strain of the virus has emerged.

Initially, 21 per cent of Canada's population was being monitored, but it's now grown to more than 60 per cent across the country, Poliquin said.

Survey results published last month in The Lancet journal show that Canada was one of the top countries, among 43 that participated, whose wastewater surveillance efforts covered the majority of the population. The article goes on to emphasize how significant this sort of testing tool has proven to track current and emerging health threats.



People receive a dose of the COVID-19 vaccine at a mass vaccination clinic at Scotiabank Arena in Toronto on June 27, 2021. The pandemic was recently downgraded from global emergency status. 

(Cole Burston/The Canadian Press)

Although the COVID-19 pandemic was recently downgraded from global emergency status, continued wastewater surveillance is still very important, said Eric Arts, Canada Research Chair in viral pathogenesis and control at Western University in London, Ont.

"It's too easy for the general public to see it and say, 'Well, [COVID-19] is no longer here, so why are we bothering with this?' And it's getting the information out that says ... 'You don't listen to the weatherman most of the time, but when you see a storm rolling in, you really wish you would have listened,'" Arts said in an interview with CBC News.

"It's preparing our health-care system for an impending wave."

Whether that's a new subvariant of COVID-19 or a range of other infectious diseases, Arts said advance warning could help the health-care system get ahead by rolling out protections and preventative measures.

Wastewater could indicate next pandemic

The federal government is also routinely monitoring wastewater for polio, mpox (formerly known as monkeypox), the flu and respiratory syncytial virus (RSV).

But Arts said he's most interested in using wastewater to get ahead of the unknown.

"[There are] new pathogens that might jump into the human population that we're not fully aware of," he said.

But if scientists don't know what they're looking for, how will they be able to tell it's in the wastewater?



This graph shows the standardized concentration of SARS-CoV-2 in Ontario's wastewater systems. Across Canada, the provinces and territories actively monitoring their wastewater for COVID-19 all display it in different ways, making it hard to draw comparative conclusions across each region. Creating a national strategy would help with the way this data is presented, researchers say. 

(Public Health Ontario)

"There's rapid advancement in technologies, and we can now monitor things that are novel and that are coming into the population, as long as we maintain these surveillance programs," he said.

Arts said he's part of a program that is looking at a way to monitor all of the possible strains of coronaviruses and influenza viruses that have the potential to infect humans.

"The tools we have at hand make the surveillance of those tens of thousands of strains actually not that difficult and not that cost prohibitive," he said.

"So when something does appear that shouldn't be in human wastewater, we can say, 'Hmm, that's something to keep an eye on,' and then alert the public health agencies."

Governments and health officials, he said, could prepare vaccines for these other possibly infectious strains and have them on hand to mass produce should a pandemic arise.

But there is some concern among those in the wastewater surveillance field that despite how essential this new technology is, monitoring could be cut if governments tighten their budgets.

Will monitoring continue?

The federal government's national wastewater monitoring system currently works with local researchers and labs to collect information from key sites. Additionally, some provinces and territories are funding their own efforts to monitor wastewater at a more local level.

At this time, there's no requirement for provinces to collect this data, nor is there any firm national strategy around a standardized procedure or collaborative database to hold this information.

Wastewater researchers are calling on Ottawa to create a national strategy that will consolidate this data and better inform the country's public health status.

While Poliquin, of the National Microbiology Laboratory, said he doesn't have a "definitive" answer on the next steps for this surveillance system, he told CBC News that ongoing conversations are taking place and work is being done to sustain and expand it.

"The technology has proven its value," he said. "There's a lot of potential here, and now that the network and infrastructure has been put in place, we are looking to continue to support it."

Poliquin said the scale of it is also cost-effective, with an individual PCR test costing $50 to $100 a person and a wastewater sample test costing $100 to $200.

In order for a national strategy to be effective, Arts said, the government needs to get all public health agencies on board, look at standardizing the procedure across the country and ensure that it consolidates the work out of specific centres.

Border surveillance top priority, say researchers

But if governments decide to scale back this type of warning system, researchers say it's most important to keep monitoring Canada's points of entry, such as borders and airports.

"Twenty-five to 30 per cent of Canada-U.S. trade crosses the border at Windsor-Detroit, making it the strategic location to place resources to be monitoring for diseases emerging in the country," said Mike McKay, executive director of the Great Lakes Institute for Environmental Research (GLIER) at the University of Windsor, in Windsor, Ont.



Mike McKay, executive director of the Great Lakes Institute for Environmental Research at the University of Windsor, says Canada's borders are an important place to continue wastewater surveillance for any incoming illnesses. 

(Dale Molnar/CBC)
McKay, who has been monitoring the wastewater in southwestern Ontario and parts of the United States since the early months of the pandemic, said this type of surveillance will also help the private sector so that supply chains become more resilient.

He said GLIER is working alongside groups at the University of Guelph, University of Waterloo, York University and University of Toronto to pitch a cross-border surveillance program to the federal government.

This would include monitoring in Ohio, Michigan and into Windsor, as well as the Fort Erie, Ont., and Buffalo, N.Y., areas, he said.

The application will be submitted by September, and Ottawa is expected to to make a decision early next year. If accepted, the program would be part of a government-funded initiative around pandemic preparedness.

Artificial sweetener as wastewater tracer

New study by the University of Vienna shows what the sweetener acesulfame reveals about groundwater flows

Peer-Reviewed Publication

UNIVERSITY OF VIENNA

Acesulfame is a sweetener in sugar-free drinks and foods. As it cannot be metabolised in the human body, the sweetener ends up in wastewater after consumption and remains largely intact even in sewage treatment plants. A new study by the University of Vienna shows that the persistence of the sweetener varies with temperature as the concentration of the sweetener in wastewater varies with the seasons. The environmental geosciences team analysed how groundwater flows can be traced based on these seasonal fluctuations. Since residues of the sweetener end up in drinking water, acesulfame serves as an indicator of the origin and composition of our drinking water. The study has now been published in the journal Water Research.

The sugar substitute acesulfame is one of the most commonly used sweeteners in Europe. It is almost 200 times sweeter than sugar and temperature-stable, making it suitable for sugar-free baking and for sweetening most diet lemonades. Because the human body does not metabolise the substance, it ends up in wastewater when consumed in large quantities and remains there even after treatment, but in fluctuating concentrations. The new study by the University of Vienna shows that the substance is broken down to varying degrees over the year depending on the temperature. "For a long time, it was assumed that the potassium salt of acesulfame is not degraded at all in wastewater treatment plants. This is still true, but only in the cold season," explains Thilo Hofmann, deputy head of the Centre for Microbiology and Environmental Systems Science at the University of Vienna. "There were already initial indications that at least partial biodegradation takes place in summer. We can prove this in our study and systematically show for a longer period of time how the concentration of the sweetener in the water changes with the seasons."

Sweetener acesulfame: indicator for the flow paths of wastewater treated in sewage treatment plants

Acesulfame is a widely used indicator of wastewater discharges into surface waters and groundwater: since this sweetener is not completely degraded both in wastewater treatment plants and in the environment – after it has been discharged into water bodies with the treated wastewater – a detection of the substance in water indicates that and how much treated wastewater has entered groundwater, rivers or lakes. "If you follow the traces of the substance, you can ultimately trace flow paths of the wastewater and its mixing with groundwater," Hofmann explains. With the knowledge of seasonal fluctuations in the degradation of the substance, acesulfame becomes an even more meaningful tracer.

Computer models of groundwater flows enable risk prevention

"Our study shows that the seasonally fluctuating concentration of acesulfame can be used to better visualise and understand the processes in the subsurface, i.e. groundwater flows," says Hofmann. Wastewater components in drinking water can be recorded as well as the flow velocity of the groundwater and the mixing ratios of groundwater and river water. The environmental geoscientists evaluated river and groundwater samples that were collected regularly over eight years in a pre-alpine catchment. The research team linked their analyses to computer models that calculate water flows in the subsurface. "Such computer models are the key to risk prevention, because they can be used to understand how much river water and how much groundwater end up in the population's drinking water and how to optimise the operation of waterworks," adds the head of the research group. 

Traces of the sweetener end up in drinking water

The sweetener acesulfame thus lays a tracer trail from wastewater to river and groundwater and finally to our drinking water. "The fact that acesulfame is not degraded is basically a good thing for us hydrogeologists, because we can draw valuable information from it," says Hofmann. He adds: "However, this fact also makes us aware of our lifestyle being reflected in the wastewater and thus also in the drinking water: The sugar substitute we consume ends up back in our drinking water – albeit heavily diluted, of course."

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JOURNAL

Water Research

DOI

10.1016/j.watres.2023.119670 

ARTICLE TITLE

Seasonal biodegradation of the artificial sweetener acesulfame enhances its use as a transient wastewater tracer

As Alberta’s oilsands continue leaking toxic wastewater, aquatic wildlife face new risks


Diane Orihel, Assistant Professor, Department of Biology & School of Environmental Studies, Queen's University, Ontario, 

Chloe Robinson, Junior Research Associate, Experimental Ecology 

and Ecotoxicology Research Team, Queen's University, Ontario, 

Chris K. Elvidge, Postdoctoral Researcher in Freshwater Ecology, Carleton University

TE CONVERSATION

Sun, May 7, 2023

Three months ago, 5.3 million litres of industrial wastewater was reported to have overflowed from an Imperial Oil storage pond into a muskeg and forested area. This industrial wastewater could have filled more than two Olympic-sized swimming pools, and is now one of the largest known spills of its kind in Alberta’s history.

Then came news of a separate incident where an unknown amount of industrial wastewater has been leaking from an Imperial Oil tailings pond for the last 12 months. The leakage flows underground and then resurfaces to contaminate surface waters outside the Kearl Oil Sands Processing Plant and Mine.

These waters flow into the Athabasca River, which is part of an important waterway that supports communities in Alberta and the Northwest Territories. In addition to its significance to the Indigenous communities here, this waterway also provides crucial habitats for endangered wildlife species.

While Imperial Oil and Alberta’s energy regulator have reported no impacts on wildlife or waterways yet, the federal government believes the leaking waste is harmful to aquatic life, and has ordered Imperial Oil to take immediate action in preventing any further seepage of toxic water.

Scientists, including our group at Queen’s University, have been studying the chemicals in oilsand tailings ponds for decades to better understand their dangers and to protect wildlife from their effects.
Fish struggle to survive in contaminated waters

The mining and extraction of bitumen — a heavy crude oil with the consistency of cold molasses — produces industrial wastewater with high concentrations of several dangerous components, including salts, dissolved organic compounds and heavy metals like cadmium and lead.

Wastewater chemicals are toxic to fathead minnows, an important prey species in the oilsands region. (NOAA Great Lakes Environmental Research Laboratory), CC BY-SA

Research and real-world incidents have found that oilsands wastewater is toxic to wildlife including mammals, fish, frogs and birds.

A group of organic compounds, referred to as naphthenic acids, are responsible for most of the toxicity of wastewater. These compounds exist naturally in the region, but accumulate to harmful, unnatural levels in wastewater during the mining process. Despite this, environmental guidelines for “safe” naphthenic acid concentrations do not exist.

The concentrations of these acids in wastewater are studied to determine the extent of the threats to wildlife, and in particular to aquatic species, as their habitats are extremely susceptible to accumulating harmful pollutants.

Studies have found that fathead minnow, walleye and yellow perch experience increased mortality, physical deformities and reduced growth when exposed to naphthenic acids. These are all species commonly found in the oilsands region.

A researcher samples tanks as a part of a field experiment testing the effects of oilsands wastewater on aquatic animals. (Chloe Robinson), Author provided

In one investigation, these chemicals altered hormone levels and reduced spawning success in fish. This effect could have population-level consequences in the wild. Meanwhile, in another study, the fish showed reduced survival and abnormal swimming behaviours, even after being held in clean lake water for one month following a week-long exposure to sublethal levels of naphthenic acids.

The science clearly suggests that fish are negatively impacted by wastewater contaminants and even short-term contact can have lasting effects on animals in the affected area.

Canada’s declining amphibians face new threats

Amphibians are one of the most rapidly disappearing groups of animals in Canada, as their wetland habitats often face the threat of pollution, among other stressors. Research on wood frogs and Northern leopard frogs has raised numerous concerns.

Like with fish, studies have found that exposure to wastewater and naphthenic acids can interfere with sexual development and impair breeding in adult frogs. Tadpoles exposed to these chemicals are more likely to die, behave abnormally when escaping predators and are less likely to develop into frogs.

One of our studies found that exposure to these chemicals can also cause developing frogs to develop striking malformations, including kinked spines and missing toes.

Tadpoles exposed to wastewater chemicals (right) show malformations not present in tadpoles raised in clean water (left) like shorter limbs, swollen bodies, and missing toes. (Chloe Robinson), Author provided

Science suggests that if pollutants reach dangerous levels due to spills, it could impair the survival and health of aquatic wildlife in affected areas. Over time, these impacts could cause wildlife population declines and even local species extinctions. Long-term monitoring will be crucial to determine the full impact of these spills.
A need for transparent oilsands waste management

In addition to wildlife, industrial activities in the oilsands region have affected the Indigenous communities over the years as well.

Indigenous Nations located downstream of recent oil spills in Alberta — including the Athabasca Chipewyan First Nation and Mikisew Cree First Nation — voiced their concern over this pollution and its impact on the plants and animals they harvest for food.

While these communities rely on the lands and waters near the spill, they were only notified of the contamination when the provincial regulator issued an environmental protection order in February.

The lack of transparency and delayed responses surrounding these current spills raises questions about how many undocumented incidents could be taking place every year.

In April, while Alberta continued to deal with the aftermath of these incidents, another 6 million litres of water spilled from a Suncor settling pond into the Athabasca River. The current method of managing wastewater is neither safe nor sustainable.

Change is needed to ensure that economic activities do not jeopardize the environment further. As government, industry and Indigenous partners begin the process of building new management and monitoring plans, which will likely include guidelines for treating and releasing oilsands wastewater back into waterways, it is important that the science is not forgotten.

Evidence-informed policies, built on what we know about the toxic extent of wastewater, have the potential to make accidental spills, and the environmental and social injustices they perpetuate, a thing of the past.

This article is republished from The Conversation, an independent nonprofit news site dedicated to sharing ideas from academic experts. 

It was written by: Diane Orihel, Queen's University, Ontario; Chloe Robinson, Queen's University, Ontario, and Chris K. Elvidge, Carleton University.

Read more:

New technology makes wastewater from the oilsands industry safer for fish

How plants can help clean up oilsands tailing ponds

Diane Orihel received funding from Environment and Climate Change Canada for her lab's research on the effects of oilsands contaminants on aquatic biota.

Chloe Robinson received funding from Queen's University (Craigie Fellowship), and the Government of Ontario (Ontario Graduate Scholarship).

Chris K. Elvidge is affiliated with the Fish Ecology and Conservation Physiology Laboratory at Carleton University.