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Could gas flaring from Woodfibre LNG pose a health threat to Squamish residents?

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Monday, November 25, 2024

As construction begins on the Woodfibre LNG facility in Squamish, B.C., residents are worried about air pollution and health impacts from flaring — the process of burning off excess gas. Missing environmental assessment data doesn’t quell their fears

As construction begins on the Woodfibre LNG facility in Squamish, B.C., residents are worried about air pollution and health impacts from flaring — the process of burning off excess gas. Missing environmental assessment data doesn’t quell their fears

As construction begins on the Woodfibre LNG facility in Squamish, B.C., residents are worried about air pollution and health impacts from flaring — the process of burning off excess gas. Missing environmental assessment data doesn’t quell their fears
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We may finally know what a healthy gut microbiome looks like

Our gut microbiome has a huge influence on our overall health, but we haven't been clear on the specific bacteria with good versus bad effects. Now, a study of more than 34,000 people is shedding light on what a healthy gut microbiome actually consists of

The trillions of microscopic bacteria that reside in our gut have an outsized role in our healthTHOM LEACH/SCIENCE PHOTO LIBRARY We often hear talk of things being good for our microbiome, and in turn, good for our health. But it wasn’t entirely clear what a healthy gut microbiome consisted of. Now, a study of more than 34,000 people has edged us closer towards understanding the mixes of microbes that reliably signal we have low inflammation, good immunity and healthy cholesterol levels. Your gut microbiome can influence your immune system, rate of ageing and your risk of poor mental health. Despite a profusion of home tests promising to reveal the make-up of your gut community, their usefulness has been debated, because it is hard to pin down what defines a “good” microbial mix. Previous measures mainly looked at species diversity, with a greater array of bacteria being better. But it is difficult to identify particular communities of interacting organisms that are implicated in a specific aspect of our health, because microbiomes vary so much from person to person. “There is a very intricate relationship between the food we eat, the composition of our gut microbiome, and the effects the gut microbiome has on our health. The only way to try to map these connections is having large enough sample sizes,” says Nicola Segata at the University of Trento in Italy. To create such a map, Segata and his colleagues have assessed a dataset from more than 34,500 people who took part in the PREDICT programme in the UK and US, run by microbiome testing firm Zoe, and validated the results against data from 25 other cohorts from Western countries. Of the thousands of species that reside in the human gut, the researchers focused on 661 bacterial species that were found in more than 20 per cent of the Zoe participants. They used this to determine the 50 bacteria most associated with markers of good health – assessed via markers such as body mass index and blood glucose levels – and the 50 most linked to bad health. The 50 “good bug” species – 22 of which are new to science – seem to influence four key areas: heart and blood cholesterol levels; inflammation and immune health; body fat distribution; and blood sugar control. The participants who were deemed healthy, because they had no known medical conditions, had about 3.6 more of these species than people with a condition, while people at a healthy weight hosted about 5.2 more of them than those with obesity. The researchers suggest that good or bad health outcomes may come about due to the vital role the gut microbiome plays in releasing chemicals involved in cholesterol transport, inflammation reduction, fat metabolism and insulin sensitivity. As to the specific species that were present, most microbes in both the “good” and “bad” rankings belong to the Clostridia class. Within this class, species in the Lachnospiraceae family featured 40 times, with 13 seemingly having favourable effects and 27 unfavourable. “The study highlights bacterial groups that could be further investigated regarding their potential positive or negative impact [on] health conditions, such as high blood glucose levels or obesity,” says Ines Moura at the University of Leeds, UK. The link between these microbes and diet was assessed via food questionnaires and data logged on the Zoe app, where users are advised to aim for at least 30 different plants a week and at least three portions a day of fermented foods, with an emphasis on fibre and not too many ultra processed options. The researchers found that most of the microbes either aligned with a generally healthy diet and better health, or with a worse diet and poorer health. But 65 of the 661 microbes didn’t fit in. “These 65 bacteria are a testament to the fact that the picture is still more complex than what we saw,” says Segata, who also works as a consultant for Zoe. “The effects may depend on the other microbes that are there, or the specific strain of the bacterium or the specific diet.” This sorting of “good” versus “bad” bacteria has enabled the researchers to create a 0 to 1000 ranking scale for the overall health of someone’s gut microbiota, which is already used as part of Zoe’s gut health tests. “Think of a healthy gut microbiome as a community of chemical factories. We want large numbers of species, we want the good ones outnumbering the bad ones, and when you get that, then you’re producing really healthy chemicals, which have impacts across the body,” says team member Tim Spector at King’s College London and co-founder of Zoe. This doesn’t mean the ideal healthy gut microbiome has been pinned down, though. “Defining a healthy microbiome is a difficult task, as the gut microbiome composition is impacted by diet, but it can also change with environmental factors, age and health conditions that require long-term medication,” says Moura. “We really need to think about our body and our microbiome as two complex systems that together make one even more complex system,” says Segata. “When you change one thing, everything is modified a bit as a consequence. Understanding what is cause and effect in many cases can be very intricate.” Bigger studies are needed to tease out these links and cover more of the global population, says Segata. However, once we have established the baseline of your health and microbiome, it should become possible to recommend specific foods to tweak your gut bacteria, he says.

How eating oysters could help restore South Australia’s algal-bloom ravaged coast

South Australians are heartbroken about the state’s unprecedented algal bloom. But eating oysters, donating shells and restoring lost reefs will boost ocean health.

South Australians are suddenly hearing a lot about oyster reefs — from government, on the news and in conversations, both online and in person. It’s not accidental. Their state is grappling with an unprecedented and harmful algal bloom. The crisis has drawn attention to another, long-forgotten environmental disaster beneath the waves: the historical destruction of native shellfish reefs. Reefs formed by native oysters, mussels and other aquatic mollusks carpeted more than 1,500 kilometres of the state’s coastline, until 200 years ago. In fact, they went well beyond the state border, existing in sheltered waters of bays and estuaries from the southern Great Barrier Reef to Tasmania and all the way around to Perth. These vast communities of bivalves, which feed by drawing water over their gills, would have helped clean the ocean gulfs and supported a smorgasbord of marine life. Their destruction by colonial dredge fisheries — to feed the growing colony and supply lime for construction — has left our contemporary coastlines more vulnerable to events like this algal bloom. And their recovery is now a central part of South Australia’s algal bloom response. Dominic Mcafee snorkels over a restored oyster reef at Coffin Bay. Stefan Andrews, CC BY-ND Rebuilding reefs South Australia’s A$20.6 million plan aims to restore various marine ecosystems, with two approaches to restore shellfish reefs. The first is building large reefs with limestone boulders. These have been constructed over the past decade with some positive results. Four have been built in Gulf St Vincent near Adelaide. Boulder reefs provide hard, stable substrate for baby oysters to settle and grow on. When built at the right time in early summer, when oyster babies are abundant and searching for a home, oyster larvae can settle on them and begin growing. But these are large infrastructure projects – think cranes, barges and boulders – and therefore take years to plan and execute. So alongside these large reef builds, the public will have the chance to help construct 25 smaller community-based reefs over the next three years. From Kangaroo Island to the Eyre Peninsula, these reefs will use recycled shells collected from aquaculture farms, restaurants and households using dedicated shell recycling bins. There will soon be a dedicated website for the project. The donated shells will be cleaned, sterilised by months in the sun, and packaged into biodegradable mesh bags and degradable cages to provide many thousands of “reef units”. From these smaller units, big reefs can grow. This combined approach — industrial-scale reefs and grassroots restoration — reflects both the scale of the ecological problem and the appetite for public participation. A 3D model of a community-based reef underwater with panels to monitor oyster settlement. Manny Katz, EyreLab, CC BY-ND What about the algal bloom? Little can be done to disperse an algal bloom of this magnitude once it has taken root. Feeling like powerless witnesses to the disaster, the ecological grief and dismay among coastal communities is palpable. Naturally, attention turns to recovery – what can be done to repair the damage? This is where oysters come in. They cannot stop this bloom. And their restoration is not a silver bullet for addressing the many stressors facing the marine environment. But healthy ecosystems recover faster and are more resilient to future environmental shocks. For shellfish reefs, South Australia already has some impressive runs on the board. Over nearly a decade we have undertaken some of the largest shellfish restorations in the Southern Hemisphere. Millions of oysters have found a home on our extant reefs, providing filtration benefits and supporting diverse marine life. And although the algal bloom has decimated many bivalve communities, thankfully native oysters have been found to have a level of resilience. During a dive last week we witnessed new baby oysters that had recently settled on the reefs, seeding its recovery. In the past decade we have built a scientific evidence base, practical knowledge, and community enthusiasm for reef restorations that benefits the broader marine ecosystem. This is why shellfish reefs feature so prominently in the algal bloom response plan. A site of oyster reef restoration in South Australia. Stefan Andrews, CC BY-ND Where will these new reefs go? We need time to identify the best sites for big boulder reefs. For now, the priority is monitoring the ecological impacts and resilience to the ongoing algal bloom. But work on community-based reef projects has already begun . These reefs will broaden our scientific understanding of how underwater animals and plants find them. Sites will be chosen based on ecological knowledge and community interest in ongoing marine stewardship. There are many ways communities can take part. Community involvement and education is a cornerstone of the work, and individuals can recycle their oyster, scallop and mussel shells. The public can also volunteer time to join shell bagging and caging events, and even get involved building the reefs. In time, there will opportunities for the community to help with monitoring and counting the oysters and other critters settled on the recycled shell. A native oyster reef in Coffin Bay, South Australia. Stefan Andrews, CC BY-ND Future built from the past The impact of this harmful algal bloom is real and ongoing. But in responding to it, South Australians are rediscovering a forgotten marine ecosystem. Rebuilding shellfish reefs won’t fix it — but alongside catchment management, seagrass restoration, fisheries management and improved monitoring and climate action, it is a powerful tool. With the help of communities, reefs that were once broken, forgotten and functionally extinct, can be returned. It will take time for these reefs to support cleaner waters and richer marine life. But these community initiatives can show people that we all have a role to play in caring for coastlines. Dominic McAfee receives funding from the South Australian Department for Environment and Water. Sean Connell receives funding from The Australian Research Council and South Australian Department for Environment and Water. He is a Director of AusOcean, a non-profit organisation in South Australia that develops and deploys open-source, low-cost marine technology to help solve ocean science and conservation challenges.

Tijuana River sewage still pollutes the San Diego Coast. She’s fighting to clean it up

The Tijuana River’s sewage contamination continues to sicken communities in southern San Diego County. San Diego County Supervisor Paloma Aguirre has become a leading force in pushing for binational fixes and emergency funding to protect public health.

In summary The Tijuana River’s sewage contamination continues to sicken communities in southern San Diego County. San Diego County Supervisor Paloma Aguirre has become a leading force in pushing for binational fixes and emergency funding to protect public health. Hours after a November storm, the Tijuana River flooded a grove of trees in Imperial Beach, gushed through a row of calverts and exploded into mounds of fetid foam.  This is ground zero for the contaminated river, which sickens thousands of people in southern San Diego County. “The Tijuana River is one of, if not the most polluted, river in the entire United States,” said San Diego County Supervisor Paloma Aguirre, who viewed the overflowing river wearing black rain boots and a hot pink respirator mask. “The river is carrying dangerous chemicals, pollutants, pathogens and toxic gases that are impacting South San Diego communities.” The site, known as the Saturn Boulevard hot spot, is part of a system of polluted waterways and failed sewage treatment plants in the cross-border region. In the ocean, the contamination leaves swimmers and surfers with breathing problems, digestive illness and rashes. Unsafe conditions have closed parts of the Imperial Beach shoreline for three years. Last year, researchers discovered that the pollution is airborne as well. Foul-smelling hydrogen sulfide emissions near the river sometimes rise hundreds of times higher than the state’s odor threshold. At those levels the gas triggers headaches, nausea, eye irritation and respiratory distress. And there are other chemicals, viruses and bacteria in the mix.  For children, the effects are worse, said Tom Csanadi, an Imperial Beach physician who has been active in the issue. Their lung surface area to body size is higher, which means they absorb more toxins. Children breathe faster than adults and they’re still growing, so it can affect their body tissues more severely. There are 11 schools within three kilometers of the hot spot. “It could lower IQ, stunt cognitive development,” Csanadi said. As a surfer, activist and elected leader, Aguirre has spent two decades tackling this problem, which she considers one of the worst environmental crises in the country. “She’s been at the forefront of the advocacy side of this for a long, long time, before her political career even started,” said Falk Feddersen, an oceanographer with Scripps Institution of Oceanography who has mapped sewage flows up the coast from Mexico. A cocktail of chemicals While storm water seeped across the road at the hot spot, a swiftwater rescue truck drove through puddles, scanning for stranded motorists. The culverts under the crossing were installed to keep flooding under control, but they also churn the water, spewing noxious gas and other pollutants.  “The unintended consequence is that it’s exacerbating the release of all the molecules and aerosols into the air,” Aguirre said. “It’s literally rocketing them into the environment.” Hydrogen sulfide, with its distinctive rotten egg odor, is an indicator of that toxic brew, said Kim Prather, an atmospheric chemist at Scripps Institution of Oceanography. She raised the alarm about airborne pollution from the Tijuana River last year. Flooding caused by the Tijuana River covers a section of Saturn Boulevard after a rainy day in San Diego on Nov. 21, 2025. Photo by Adriana Heldiz, CalMatters Layers of foam caused by sewage and chemicals bubble up along a section of the Tijuana River after a rainy day in San Diego on Nov. 21, 2025. Photo by Adriana Heldiz, CalMatters Layers of foam caused by sewage and chemicals bubble up along a section of the Tijuana River after a rainy day in San Diego on Nov. 21, 2025. Photo by Adriana Heldiz, CalMatters “That’s one in a cocktail of thousands of compounds,” she said. “It’s a blessing that it smells. I know it sounds strange, but it tells you to get away.” Aguirre described her own struggles with Tijuana River pollution, including migraines, chest pain, shortness of breath, and waking in the middle of the night to an odor she likened to a “porta potty.” Recent improvements to wastewater treatment plants in the U.S. and Mexico have reduced water pollution by keeping tens of millions of gallons of sewage out of the ocean each day. Aguirre and others celebrate that news, but note the river still contaminates surrounding areas. More big upgrades are in the works on both sides of the border, but fixing the Saturn Boulevard hot spot quickly could offer immediate relief, Aguirre said. “This is a very specific and low hanging fruit that will at least begin to mitigate the amount of gases being released into the air and benefit tens of thousands of people that live here,” she said. Waves of pollution Tijuana River pollution dates back to at least the 1930s, when the U.S. and Mexican governments built the first cross-border sewage plants. As Tijuana’s population soared with its booming industry, the city’s waste outstripped its treatment systems. Plant failures and sewage spills became common in the early 2000s, along with frequent beach closures along the south San Diego coast. That’s when Aguirre encountered cross-border pollution in the surf at Imperial Beach. Growing up in Puerto Vallarta Mexico, she was used to surfing in muddy water after rains, so the discolored waves didn’t seem worrisome.  “I remember going out here in Imperial Beach while the water was chocolate brown, not knowing that it’s nothing like what I was used to, because that was sewage,” she said. She was the only one at the beach that day, except for a man posting signs stating “Clean water now.” He was Serge Dedina, executive director of the environmental group WildCoast, and he enlisted her in the fight against sewage pollution. Aguirre first volunteered for the organization and soon joined its staff. She worked there for more than a decade, while earning a master’s degree in marine biodiversity and conservation at Scripps Institution of Oceanography. At WildCoast she organized a citizens’ group, advocated for improved water testing using DNA analysis, and served on working groups for a binational agreement on cross-border pollution, called Minute 320. When Dedina was elected mayor of Imperial Beach in 2014, Aguirre saw a path to solving the sewage problem. “I thought, well, if he can do it I can do it,” she said. “And I built on the momentum that he was able to create on this issue.” San Diego County Supervisor Paloma Aguirre wears a respiratory filter mask while standing near a section of the Tijuana River in San Diego on Nov. 21, 2025. Photo by Adriana Heldiz, CalMatters A warning sign about sewage and chemical contamination is posted along the shore of Imperial Beach on Nov. 21, 2025. Photo by Adriana Heldiz, CalMatters Aguirre won a seat on the Imperial Beach City Council in 2018 and was elected mayor in 2022, when Dedina left office. With a bigger platform, she called on California and the federal government to declare a state of emergency over the border pollution problem and lobbied to classify the area as a Superfund site. Those efforts haven’t gained traction, but other angles yielded results. Imperial Beach sued the International Boundary and Water Commission with the city of Chula Vista and Port of San Diego in 2018, alleging that it violated the Clean Water Act and other federal laws by failing to control coastal sewage pollution. They settled the lawsuit in 2023 with a promise of more resources and binational cooperation.  “My tenure as mayor of IB really focused on advocating and working in a bipartisan fashion to secure the additional funding that was needed,” to fix cross-border pollution, she said. A person walks their dog near the Imperial Beach Pier in Imperial Beach on Nov. 21, 2025. Photo by Adriana Heldiz, CalMatters Aguirre led delegations of local officials to Washington, D.C. to drum up money for costly infrastructure upgrades needed to get the sewage problem under control. She met with White House officials in both the Biden and Trump administrations, and with lawmakers who had served as Navy SEALS and had experienced the pollution problem at BUD/S, the Navy SEAL training program in Coronado. In July, Aguirre won a special election for an open San Diego County Board of Supervisors seat. She immediately led county plans to study the health effects of cross-border pollution and asked the state for $50 million to fix the Saturn Boulevard hot spot.  “She’s moved a problem that has been stuck, when other people could not,” Prather, the Scripps atmospheric chemist, said. Sewage spills prompt quick fixes The long-standing pollution problem came under new scrutiny in 2017, when a spill from a damaged line in Mexico dumped an estimated 143 million gallons of wastewater into the Tijuana River, sending foul odors wafting through the region. That accident revealed just how dilapidated the aging infrastructure had become. “That’s one of the reasons why things are so horrific, because they’re playing catch up on fixing these things when they have catastrophic failures,” said Feddersen, the Scripps oceanographer. In early 2022, another major spill released hundreds of millions of gallons of sewage-tainted water across the border for two and a half weeks.  That summer, San Diego congress members freed up more than $300 million that had been authorized for wastewater treatment upgrades through the United States-Mexico-Canada Agreement. Mexico committed $144 million to replace failing sewage treatment facilities in Tijuana, with an updated treaty between the two countries known as Minute 328. In 2024, the lawmakers persuaded the Biden administration to add another $370 million to repair the aging South Bay International Wastewater Treatment Plant near the border, Rep. Scott Peters said. After decades of deterioration, major improvements came online this year. The South Bay International Wastewater Treatment Plant, which was barely operable, is now fully functioning and expanded its capacity from 25 million to 35 million gallons of wastewater per day. The project was expected to take two years, but was completed in 100 days, according to the U.S. International Boundary and Water Commission. An aerial view shows a treated wastewater river heading to the Pacific Ocean near Real Del Mar in Tijuana, Baja California, Mexico on Aug. 12, 2025. Photo by Guillermo Arias, AFP via Getty Images By the end of next year that will climb to 50 million gallons per day, with higher capacity for peak wastewater surges. The commission, which manages the wastewater systems, has spent $122 million on the first series fixes, and the full project will cost $650 million. Although the Trump administration has clawed back federal funding for many projects, it has doubled down on the cross-border sewage problem, Aguirre said. In July U.S. Environmental Protection Agency Administrator Lee Zeldin met with his Mexican counterpart to seal the environmental deal. In April Mexico repaired its Punta Bandera plant, located on the coast about six miles south of the border. The plant had failed completely in 2020 and was dumping raw sewage into the ocean. It now handles 18 million gallons of wastewater per day. That’s a big boost for beach safety, said Feddersen, whose research tracked the flow of sewage in ocean currents and modeled scenarios for reducing it. “The best bang for the buck, the greatest reduction in beach closure and reduction in human illness, was fixing Punta Bandera,” he said. Yet, the Tijuana River still threatens residents in its watershed with untreated sewage and industrial chemicals from maquiladoras in Tijuana. That includes solvents, heavy metals and toxins known as PFAS, or “forever chemicals,” Prather said. “The river right now is a wastewater treatment plant without any processing,” she said. Removing the culverts would eliminate the turbulence that sprays out hydrogen sulfide and other toxins. The county plans to finish a feasibility study on the project by January. That project would keep contaminants out of the air, but not out of the water. Aguirre also wants new infrastructure to clean up the Tijuana River on the U.S. side. The recent binational Treaty, Minute 328, includes that option, and the International Boundary and Water Commission is exploring what it would take to divert and treat the river flows. There’s no funding for the project yet, but Aguirre says it’s on her agenda. “Rivers are diverted up and down,” she said.  “It’s doable. Is it expensive? Yes. Are our lives in South San Diego worth it? Yes.”

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