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Pollution Solution: Scientists Develop Living Plastics That Degrade in Compost or Erosion

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Saturday, August 31, 2024

Plastics are widely used but difficult to degrade, posing an ecological challenge. A team from SIAT developed degradable “living plastics” using synthetic biology and polymer engineering. They engineered Bacillus subtilis spores to produce Burkholderia cepacia lipase (BC-lipase), an enzyme that breaks down plastic. These spores were mixed with poly(caprolactone) (PCL) to create the plastics, maintaining the material’s physical properties. When the plastic surface is eroded, the spores release the enzyme, leading to a nearly complete breakdown of the plastic. Credit: Dai ZhuojunScientists developed engineered spores embedded in plastics that remain stable during use but degrade rapidly when exposed to specific environmental triggers. This innovative approach could significantly mitigate plastic pollution. The findings, led by Dr. Dai Zhuojun’s research group at the Shenzhen Institute of Advanced Technology (SIAT), Chinese Academy of Sciences (CAS), were recently published in Nature Chemical Biology. The study leverages the natural resilience of spores, which can endure extreme environmental conditions, by programming them to secrete plastic-degrading enzymes under specific circumstances. These spores are embedded into plastic matrices through standard plastic processing methods, such as high temperature, high pressure, or the use of organic solvents. In normal conditions, the spores remain dormant, ensuring the plastic’s stable performance. However, when exposed to specific triggers like surface erosion or composting, the spores activate and initiate the degradation process, leading to the plastic’s complete breakdown. Research Background The invention of plastics has improved our daily lives, but the massive production and improper disposal of plastic waste have made plastic pollution a major environmental issue. In 2016, Yoshida et al. discovered a bacterium, Ideonella sakaiensis, in poly (ethylene terephthalate) (PET)-contaminated soil near a recycling facility in Japan. This bacterium can grow using PET as its main carbon source by producing two key enzymes: PETase and MHETase. Since then, numerous synthetic biology research has been focused on discovering, designing, and evolving the relevant plastic-degrading enzymes, but there has been little exploration of innovative methods for creating degradable plastics. Dormant Spores and Living Plastics Microorganisms have developed intrinsic mechanisms to defend against harsh conditions over billions of years. One classical example is the formation of spores that are resilient to dryness, high temperatures, and high pressure (similar conditions in plastics processing). Using synthetic biology, the research team engineered Bacillus subtilis with a genetic circuit to control the secretion of a plastic-degrading enzyme (lipase BC from Burkholderia cepacia). Under stress from heavy metal ions, Bacillus subtilis forms spores. The team mixed these engineered spores with poly (caprolactone) (PCL) plastic granules and produced spore-containing plastics through high-temperature extrusion or solvent dissolution. Tests showed that these “living plastics” had similar physical properties to regular PCL plastics. During daily use, the spores remain dormant, ensuring the plastic’s stable performance. Spore Release and Degradation Initiation The first key step in plastic degradation is to release the spores embedded in the living plastic for cell revival. Researchers have first demonstrated two methods of spore release. One method uses an enzyme (lipase CA) to erode the plastic surface. These released spores then germinated and expressed the lipase BC, which bound to the ends of PCL polymer chains and near-completely degraded the PCL molecules (final molecular weight <500 g/mol). The results showed that living plastic could degrade efficiently within 6-7 days, while ordinary PCL plastic subjected only to surface damage (lipase CA) still had a large amount of plastic debris after 21 days. Another method for spores release is composting. In the absence of any additional exogenous agents, living plastics in soil could completely degrade within 25-30 days, while traditional PCL plastic took about 55 days to degrade to a level that was invisible to the naked eye. Beyond PCL Plastics As mentioned earlier, PCL’s processing conditions are relatively ‘mild’ among plastics. To verify the system’s general applicability, the team continued to test other commercial plastic systems. They mixed spores carrying GFP expression plasmids with PBS (polybutylene succinate), PBAT (polybutylene adipate-co-terephthalate), PLA (polylactic acid), PHA (polyhydroxyalkanoates), and even PET (poly (ethylene terephthalate)) and processed the mixture at temperatures as high as 300oC. By releasing the spores through physical grinding, they surprisingly found that the spores could still revive and expressed the GFP. These results have laid a solid foundation for extending the method with other types of plastics. To validate the potential for scaling up the system, the research team also conducted a small-scale industrial test on PCL system using a single-screw extruder. The generated living PCL still exhibited rapid and efficient degradation property (degrade within 7 days). In the absence of external factors, the living PCL maintained a stable shape, demonstrating its robustness during the service (stable in Sprite for two months). This study provides a novel method for fabricating green plastics that can function steadily when the spores are latent and decay when the spores are aroused and shed light on the development of materials for sustainability. Reference: “Degradable living plastics programmed by engineered spores” by Chenwang Tang, Lin Wang, Jing Sun, Guangda Chen, Junfeng Shen, Liang Wang, Ying Han, Jiren Luo, Zhiying Li, Pei Zhang, Simin Zeng, Dianpeng Qi, Jin Geng, Ji Liu and Zhuojun Dai, 21 August 2024, Nature Chemical Biology.DOI: 10.1038/s41589-024-01713-2

Scientists developed engineered spores embedded in plastics that remain stable during use but degrade rapidly when exposed to specific environmental triggers. This innovative approach could significantly mitigate plastic pollution. The findings, led by Dr. Dai Zhuojun’s research group at the Shenzhen Institute of Advanced Technology (SIAT), Chinese Academy of Sciences (CAS), were recently published in [...]

Living Plastics Degradation
Plastics are widely used but difficult to degrade, posing an ecological challenge. A team from SIAT developed degradable “living plastics” using synthetic biology and polymer engineering. They engineered Bacillus subtilis spores to produce Burkholderia cepacia lipase (BC-lipase), an enzyme that breaks down plastic. These spores were mixed with poly(caprolactone) (PCL) to create the plastics, maintaining the material’s physical properties. When the plastic surface is eroded, the spores release the enzyme, leading to a nearly complete breakdown of the plastic. Credit: Dai Zhuojun

Scientists developed engineered spores embedded in plastics that remain stable during use but degrade rapidly when exposed to specific environmental triggers. This innovative approach could significantly mitigate plastic pollution.

The findings, led by Dr. Dai Zhuojun’s research group at the Shenzhen Institute of Advanced Technology (SIAT), Chinese Academy of Sciences (CAS), were recently published in Nature Chemical Biology.

The study leverages the natural resilience of spores, which can endure extreme environmental conditions, by programming them to secrete plastic-degrading enzymes under specific circumstances. These spores are embedded into plastic matrices through standard plastic processing methods, such as high temperature, high pressure, or the use of organic solvents.

In normal conditions, the spores remain dormant, ensuring the plastic’s stable performance. However, when exposed to specific triggers like surface erosion or composting, the spores activate and initiate the degradation process, leading to the plastic’s complete breakdown.

Research Background

The invention of plastics has improved our daily lives, but the massive production and improper disposal of plastic waste have made plastic pollution a major environmental issue. In 2016, Yoshida et al. discovered a bacterium, Ideonella sakaiensis, in poly (ethylene terephthalate) (PET)-contaminated soil near a recycling facility in Japan.

This bacterium can grow using PET as its main carbon source by producing two key enzymes: PETase and MHETase. Since then, numerous synthetic biology research has been focused on discovering, designing, and evolving the relevant plastic-degrading enzymes, but there has been little exploration of innovative methods for creating degradable plastics.

Dormant Spores and Living Plastics

Microorganisms have developed intrinsic mechanisms to defend against harsh conditions over billions of years. One classical example is the formation of spores that are resilient to dryness, high temperatures, and high pressure (similar conditions in plastics processing).

Using synthetic biology, the research team engineered Bacillus subtilis with a genetic circuit to control the secretion of a plastic-degrading enzyme (lipase BC from Burkholderia cepacia). Under stress from heavy metal ions, Bacillus subtilis forms spores. The team mixed these engineered spores with poly (caprolactone) (PCL) plastic granules and produced spore-containing plastics through high-temperature extrusion or solvent dissolution. Tests showed that these “living plastics” had similar physical properties to regular PCL plastics. During daily use, the spores remain dormant, ensuring the plastic’s stable performance.

Spore Release and Degradation Initiation

The first key step in plastic degradation is to release the spores embedded in the living plastic for cell revival. Researchers have first demonstrated two methods of spore release. One method uses an enzyme (lipase CA) to erode the plastic surface.

These released spores then germinated and expressed the lipase BC, which bound to the ends of PCL polymer chains and near-completely degraded the PCL molecules (final molecular weight <500 g/mol). The results showed that living plastic could degrade efficiently within 6-7 days, while ordinary PCL plastic subjected only to surface damage (lipase CA) still had a large amount of plastic debris after 21 days.

Another method for spores release is composting. In the absence of any additional exogenous agents, living plastics in soil could completely degrade within 25-30 days, while traditional PCL plastic took about 55 days to degrade to a level that was invisible to the naked eye.

Beyond PCL Plastics

As mentioned earlier, PCL’s processing conditions are relatively ‘mild’ among plastics. To verify the system’s general applicability, the team continued to test other commercial plastic systems. They mixed spores carrying GFP expression plasmids with PBS (polybutylene succinate), PBAT (polybutylene adipate-co-terephthalate), PLA (polylactic acid), PHA (polyhydroxyalkanoates), and even PET (poly (ethylene terephthalate)) and processed the mixture at temperatures as high as 300oC.

By releasing the spores through physical grinding, they surprisingly found that the spores could still revive and expressed the GFP. These results have laid a solid foundation for extending the method with other types of plastics.

To validate the potential for scaling up the system, the research team also conducted a small-scale industrial test on PCL system using a single-screw extruder. The generated living PCL still exhibited rapid and efficient degradation property (degrade within 7 days). In the absence of external factors, the living PCL maintained a stable shape, demonstrating its robustness during the service (stable in Sprite for two months). This study provides a novel method for fabricating green plastics that can function steadily when the spores are latent and decay when the spores are aroused and shed light on the development of materials for sustainability.

Reference: “Degradable living plastics programmed by engineered spores” by Chenwang Tang, Lin Wang, Jing Sun, Guangda Chen, Junfeng Shen, Liang Wang, Ying Han, Jiren Luo, Zhiying Li, Pei Zhang, Simin Zeng, Dianpeng Qi, Jin Geng, Ji Liu and Zhuojun Dai, 21 August 2024, Nature Chemical Biology.
DOI: 10.1038/s41589-024-01713-2

Read the full story here.
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The bid to make Illinois a leader on electric trucking

A coalition of environmental justice advocates is pushing Illinois to become the first Midwest state to adopt California’s Advanced Clean Trucks standards designed to spur a transition to zero-emission heavy-duty vehicles over the next decade. “Air pollution is an equity issue,” Griselda Chavez, an environmental…

A coalition of environmental justice advocates is pushing Illinois to become the first Midwest state to adopt California’s Advanced Clean Trucks standards designed to spur a transition to zero-emission heavy-duty vehicles over the next decade. “Air pollution is an equity issue,” Griselda Chavez, an environmental justice organizer with Warehouse Workers for Justice, said at a recent press conference. The group represents workers and residents in communities heavily impacted by warehouses, including the Chicago-area town of Joliet, a major logistics hub. “Black, brown, and low-income communities in and around Joliet are disproportionately affected by diesel pollution, large amounts of truck traffic, and increasing growth of the warehouse industry,” Chavez said. ​“Those workers also go home to their families and go to schools that are surrounded by large amounts of truck traffic and poor air quality.” The Illinois Pollution Control Board is considering adopting not only California’s clean truck standards but also the Golden State’s Advanced Clean Cars II program, which would phase out the sale of most non-electric passenger vehicles by 2035, and its stricter nitrogen oxide limits on heavy-duty vehicles. The deliberations are happening as the Trump administration seeks to block California’s unique authority to set vehicle emission standards that exceed federal rules. Illinois advocates have focused mostly on the clean trucks program because of the health and environmental justice implications of diesel-powered trucks throughout the state. They are especially concerned about places like Joliet and Chicago’s Little Village neighborhood, a largely immigrant community where warehouses have also proliferated. In 2023, the Little Village Environmental Justice Organization worked with the Center for Neighborhood Technology on a truck-counting study that showed on one June day, an average of 1.5 heavy-duty trucks per minute drove along a residential street in the heart of the community. Sally Burgess, downstate lead organizing representative for Sierra Club’s Illinois chapter, told the Pollution Control Board during a March 10 hearing that she counted more than 300 diesel-burning semi-trucks during the 65-mile drive between her home in central Illinois and the state’s capitol. “All along our route, on both sides of the highway, farm fields, rustic barns, cows and other farm animals, some homes,” said Burgess. ​“Some would refer to it as a bucolic rural setting — clogged with diesel trucks.” Stimulating Illinois’ EV markets The Advanced Clean Trucks program would require manufacturers selling in Illinois to ensure that between 40% and 75% of their heavy-duty vehicle sales are zero-emissions by 2035, with the percentage depending on type of vehicle. They would have to sell higher percentages of electric medium-sized non-tractor trucks than pickup trucks and vans as well as larger tractor-trailers. Manufacturers could also comply by purchasing credits from other companies that go beyond those targets, or by shifting credits from types of vehicles where they exceed the mandates. “If, for example, a truck-maker sells a lot of zero-emission delivery vans but doesn’t offer a zero-emission version of their box trucks, they can convert their extra [pickup and van] credits into [midsize truck] credits and still maintain compliance,” said Trisha DelloIacono, head of policy for Calstart, a national nonprofit focused on clean transportation policy and market development, by email. DelloIacono said demand for zero-emissions heavy-duty vehicles is so high that manufacturers should not have trouble meeting the sales targets if they make the inventory available. After a certain number of years, those that don’t comply either through electric vehicle sales or credit purchases could be fined. Advocates say that the state mandates benefit people nationwide since they motivate manufacturers to increase their EV offerings.

Could electric drones you can sit in take off?

Skyfly's aircraft promises the flexibility of a helicopter without the cost, noise or emissions.

Could electric drones you can sit in take off?Katharine Da CostaReporting fromOxfordshireBBCThe Skyfly Axe can take off vertically like a helicopter or land on a runwayImagine an electric drone mixed with a fixed wing plane - that is the concept behind a new two-seater aircraft being developed by start-up company, Skyfly.The Axe promises the flexibility of a helicopter but without the cost, noise pollution or carbon emissions.It is a vertically capable aircraft, or Electric Vertical Take-off and Landing (eVTOL) aircraft, which means it can take off like a helicopter.It also has two fixed wings that allows it to take off and land from a runway.The company claims the Axe has a top speed of 100mph, it can carry up to 172kg - approximately the weight of two 13.5st adults - and has a range of 100 miles, about the distance from Oxford to the Isle of Wight.Michael Thompson, CEO of Skyfly, is optimistic the new model will be delivered to customers early next yearThe team, based near Banbury in Oxfordshire, has taken five years to fine tune the design."Compared to a conventional aircraft it's got eight motors which is very strange," says Dr Bill Brooks, Skyfly's chief technical engineer."And it's a tail-first layout called a canard so it's got the tail at the front. The all up weight is 750kg but 240kg of that are batteries so all the structure is carbon fibre to keep it as light as possible," Dr Brooks says.Safety is an important part of the design too. 'Environmental benefits'The large wings help it to glide in the event of power failure and there are two motors at the end of each wing so that if one fails the other can compensate.It is also equipped with an emergency ballistic parachute to bring the aircraft and passengers down safely.As well as being safer and cleaner than conventional aircraft, Michael Thompson, Skyfly's chief executive, says electric models are significantly quieter too."When you're taking off, you're no longer annoying everyone around you from a noise perspective, so I do think electric propulsion brings not only environmental benefits but from a noise pollution point of view, it's a huge benefit as well," he says.Dr Bill Brooks is the chief engineer and test pilot at SkyflyWho is it marketed at?Other eVTOLs under development include those looking to provide an electric flying-taxi service like Bristol-based Vertical Aerospace (VA) . VA, as well as Archer and Joby in the US, are designing electric powered aircraft to carry up to four passengers.Skyfly's Axe, by comparison, is more compact and aimed at the private market.The do-it-youself kit-plane comes with a price tag of £250,000.It is aimed at existing pilots who want to transition away from diesel piston engines.Jason Pritchard, executive editor of eVTOL Insights, says it is also likely to appeal to flying clubs in order to train new members:"The eVTOL aircraft industry is still in its infancy with initial operations a few years away, but it also needs to train large numbers of pilots in the coming years," he says."Additionally, the Axe's design can also train pilots with the skills and controls necessary to land an aircraft without power, which is a necessary tool."SkyflyThe two-seater light aircraft has a range of around 100 milesWhat about charging infrastructure?While the Axe can be charged up overnight with a conventional three-pin plug, just like EV cars, electric aircraft will need the charging infrastructure to be scaled up. Aerovolt, based in West Sussex, has installed rapid chargers at seven UK airports with 40 more in the pipeline.Its founder, Philip Kingsley-Dobson, says demand is growing. "A lot of piston aircraft can't use leaded fuel in the future so they're looking for alternatives and ways we can decarbonise the lower end of aviation," he says.'Cutting edge'There are no eVTOL aircraft currently permitted to fly in the UK.Skyfly's Axe has successfully completed manned test flights in both hover and forward flight modes but still needs to be certified by the Civil Aviation Authority (CAA).With 40 pre-orders from buyers all over the world, the company hopes to deliver the new model to customers early next year.A CAA spokesperson said: "We are working with innovators to test and fly brand new forms of aviation that keeps the UK at the cutting edge of flight technology and supports the sector to grow."New technology comes with new challenges and safety remains our priority in all this work."

Record number of illegal sewage spills in Windermere last year

Campaigners identified 140 illegal spill days into the beauty spot in 2024

Record number of illegal sewage spills in Windermere last yearJonah FisherBBC environment correspondentReutersSewage spilled illegally into Britain's largest lake on a record number of days last year, an analysis of water company data by campaigners suggests.The analysis, which the BBC had exclusive access to, used United Utilities operational data to establish when the company was discharging sewage into Windermere when it should by law have been treating some of it.The campaigners from Windrush Against Sewage Pollution (WASP) and Save Windermere identified 140 illegal spill days in 2024, more than in any of the three previous years. United Utilities told BBC News that the campaigners' findings were "inaccurate" and some of the data "erroneous". The company declined to put in writing, despite repeated requests, any specific examples of mistakes or omissions. Regulators Ofwat and the Environment Agency are both currently investigating United Utilities operations. PAWindermere is one of Britain's most loved beauty spotsLast week the Environment Agency said United Utilities had spilled 77,817 times in 2024, the highest figure of all England's water companies. Many of the spills will have been legal. All water companies are legally allowed to discharge raw sewage to stop the network getting overwhelmed and this now happens regularly during periods of heavy rain.But almost all pumping stations and treatment plants operate under an environmental permit which specify that they must process or "pass forward" a certain amount of sewage and rainwater before spilling starts.The campaigners cross-referenced United Utilities datasets showing when an asset was spilling against how much sewage it was treating at the time. The campaigners' analysis – which has been shared with and scrutinised by the BBC - found days when illegal spills appear to have occurred at each of six sewage facilities around the lake, which combined to 140 days in 2024. That's more than in any of the previous three years, as the chart below shows.The longest illegal spill the analysis identified was for 10 days from Hawkshead pumping station, which flows into Windermere via Cunsey Beck."This is an indication that their works have not been maintained properly or they're not being watched over properly," says Prof Peter Hammond, a mathematican and retired academic from campaign group Windrush Against Sewage Pollution. Prof Hammond's analysis of water company data has been cited by regulators and he has been praised in Parliament by water company executives for bringing problems to light they were previously unaware of. The latest analysis covers four years of data from six sites that discharge sewage into the Lake Windermere catchment.Comparisons over a longer time period are impossible as United Utilities has only had made full data sets available since 2021.Prof Hammond's analysis of water company data has been praised in ParliamentThe regulators Ofwat and the Environment Agency have since 2021 been investigating whether the water companies have been treating enough sewage before they start to spill. The EA call it a "major criminal investigation" while Ofwat call it "the largest and most complex Ofwat has ever undertaken". Last week Yorkshire Water agreed to a £40m "enforcement action" after Ofwat uncovered "serious failures" in how it operated its treatment plant and network. Ofwat declined to comment on the campaigner's findings as their investigation into United Utilities is ongoing. In response to concerns about United Utilities the Environment Agency last year reviewed all of its environmental permits in the Windermere catchment and says this led directly to the water company tripling its investment plans for the area to £200m."We are currently carrying out investigations into suspected pollution incidents on the Windermere catchment and are unable to comment on these in detail until they have reached a conclusion," an EA spokesperson said when the campaigners' analysis was shared with them."Where we find breaches of environmental permits, we will take the appropriate enforcement action up to and including a criminal prosecution."Save WindermereSewage has been blamed for turning parts of the lake green – so called "algal blooming"United Utilities, which provides services to more than seven million people across north-west England, is more than £9bn in debt. Its chief executive Louise Beardmore confirmed to parliament in February that she was last year paid £1.4m including a bonus of £420,000."The methodology used by the campaigners is different to that used by the Environment Agency for its compliance assessments," the water company said in a statement."On top of that, erroneous data has been used, tags and naming conventions in data sets appear to have been misunderstood, and assumptions seem to have been made on whether different types of flow meters have been installed.""The methodology fails to use other corroborating information from the sites which would prove that spills did not occur. As a result, the numbers quoted are inaccurate."BBC News presented United Utilities with five examples of illegal spills the campaigners' analysis had identified using the company's data and asked for any evidence or explanation as to why they were not illegal. United Utilities repeatedly declined to do so in writing or on camera."What we're seeing is the failure of privatisation. We're seeing a prioritisation of dividend returns over the long-term environmental protection of places like Windermere" says Matt Staniek from Save Windermere."The bill payer has paid for a service that has never fully been provided, and the illegality demonstrates that for all to see."Over the next five years bills in the United Utilities area will go up by 32% above the rate of inflation. On average that will mean a rise of £86 for the year that starts in April. Louise Beardmore said the rises will fund the "largest investment in water and wastewater infrastructure in over 100 years". For Windermere that's set to mean nine wastewater treatment works, including two that were included in the campaigners' analysis being upgraded and a reduction in the number of overflows discharging into the lake.

Cadia goldmine operators fined $350,000 for breaches of NSW clean-air laws

Testing had previously revealed the mine was emitting more than 11 times the legal limit of dust containing heavy metalsElection 2025 live updates: Australia federal election campaignGet our breaking news email, free app or daily news podcastThe operators of Cadia goldmine have been ordered to pay $350,000 in fines and convicted of three offences after a prosecution by the New South Wales Environmental Protection Authority.Cadia Holdings Limited, trading as Cadia Valley Operations, pleaded guilty to three offences under the environmental protection act relating to breaches of clean air regulations at the mine in central west NSW.Sign up for Guardian Australia’s breaking news email Continue reading...

The operators of Cadia goldmine have been ordered to pay $350,000 in fines and convicted of three offences after a prosecution by the New South Wales Environmental Protection Authority.Cadia Holdings Limited, trading as Cadia Valley Operations, pleaded guilty to three offences under the environmental protection act relating to breaches of clean air regulations at the mine in central west NSW.Justice Sarah Pritchard handed down her judgment in the land and environment court on Monday.The mine operator was fined $150,000 for offences in November 2021 and March 2022, and $200,000 for an offence in May 2023, but given a reduction in its penalty because of its guilty plea and other mitigating factors.It must also pay the EPA’s legal costs, and cover the cost of installing a new “dust tracking system” in Mudgee.Pritchard ordered that Newmont Australia, the owner of the mine, also had to publicise the ruling in a print advertisement in three newspapers, and on its Facebook and X accounts.Newmont acquired the previous owner, Newcrest, in November 2023.The EPA began investigating the central-west mine in 2023 after a community-driven water testing program that found elevated levels of heavy metals in the rainwater tanks of some nearby residences.It subsequently found that these levels were caused by dust emissions. The mine operator was exceeding the standard concentration for solid particles being emitted from mine surface exhaust fans at its main vent, known as Ventilation Rise 8 (VR8).In June 2023, the head of the NSW EPA criticised the operators of Australia’s largest goldmine for “completely unacceptable” levels of air pollution after testing revealed it was emitting more than 11 times the legal limit of dust containing heavy metals.skip past newsletter promotionSign up to Breaking News AustraliaGet the most important news as it breaksPrivacy Notice: Newsletters may contain info about charities, online ads, and content funded by outside parties. For more information see our Privacy Policy. We use Google reCaptcha to protect our website and the Google Privacy Policy and Terms of Service apply.after newsletter promotionThe EPA ordered the operators to take immediate action to reduce air pollution after they had provided preliminary air pollution test results to the EPA.That report found that VR8, also known as the “crusher vent” because it extracts contaminated air from where the ore is crushed deep underground, was expelling between 200 and 570 milligrams per cubic metre of dust – more than 11 times the regulatory limit for air pollution.This was despite a new ventilation system that included installing a bag house, which catches 1 tonne of dust an hour.The EPA chief executive officer, Tony Chappel, said at the time that the level of pollution recorded in those test results was “completely unacceptable” and that the mine had fallen well short of its legal obligations to meet clean air standards.“The clean air regulation states that for any point source of pollution, which that vent is, the maximum allowable standard of dust is 50 milligrams per cubic metre,” he said. “That’s the standard we’re talking about when we say they have to immediately comply.”

Mysterious foam on South Australian beaches caused by bloom of tiny but toxic algae

Algae blooms can be a problem for marine life and people but it’s not yet clear if warmer oceans and nutrient runoff are causing more of themConfronting images of dead seadragons, fish and octopuses washed up on South Australian beaches – and disturbing reports of “more than 100” surfers and beachgoers experiencing flu-like symptoms after swimming or merely breathing in sea spray – attracted international concern last week.Speculation about the likely cause ranged from pollution and algae to unusual bacterial infections or viruses. We can reveal the culprit was a tiny – but harmful – type of planktonic algae called Karenia mikimotoi. Continue reading...

Confronting images of dead seadragons, fish and octopuses washed up on South Australian beaches – and disturbing reports of “more than 100” surfers and beachgoers experiencing flu-like symptoms after swimming or merely breathing in sea spray – attracted international concern last week.Speculation about the likely cause ranged from pollution and algae to unusual bacterial infections or viruses. We can reveal the culprit was a tiny – but harmful – type of planktonic algae called Karenia mikimotoi.The South Australian government sent us water samples from Waitpinga beach, Petrel Cove beach, Encounter Bay boat ramp and Parsons Headland on Tuesday. We studied the water under the microscope and extracted DNA for genetic analysis.Our results revealed high numbers of the tiny harmful algal species – each just 20 microns in diameter (where one micron is one thousandth of a millimetre). While relatively common in Australian coastal waters, blooms of K. mikimotoi occur only sporadically. But similar harmful algal blooms and fish kills due to K. mikimotoi have happened in the past, such as the 2014 bloom in Coffin Bay, South Australia. And this latest one won’t be the last.Harmful algal bloomsSingle-celled, microbial algae occur naturally in seawater all over the world.They are also called phytoplankton because they float in the water column and photosynthesise like plants. “Phyto” comes from the Greek word for plant and “plankton” comes from the Greek word for wanderer, which relates to their floating movement with ocean currents and tides.Like plants on land, the microalgae or phytoplankton in the ocean capture sunlight and produce up to half the oxygen in our atmosphere. There are more than 100,000 different species of microalgae. Every litre of seawater will normally contain a mixed group of these different microalgae species.But under certain conditions, just a single species of microalgae can accumulate in one area and dominate over the others. If we are unlucky, the dominant species may be one that produces a toxin or has a harmful effect.This so-called “harmful algal bloom” can cause problems for people and for marine life such as fish, invertebrates such as crabs, and even marine mammals such as whales and seals.K. mikimotoi causes harmful deadly algal blooms in Asia, Europe, South Africa and South America, as well as Australia and New Zealand. Photograph: Anthony RowlandThere are hundreds of different species of harmful algae. Each produces its own type of toxin with a particular toxic effect.Most of these toxic chemical compounds produced by harmful algae are quite well known, including neurotoxins that affect the brain. But others are more complicated, and the mechanisms of toxicity are poorly understood. This can make it more difficult to understand the factors leading to the deaths of fish and other marine life. Unfortunately, the toxins from K. mikimotoi fall into this latter category.Introducing Karenia mikimotoiThe species responsible for recent events in South Australia, K. mikimotoi, causes harmful algal blooms in Asia, Europe, South Africa and South America, as well as Australia and New Zealand. These blooms all caused fish deaths, and some also caused breathing difficulties for some beachgoers.The most drastic of these K. mikimotoi blooms have occurred in China over the past two decades. In 2012, more than 300 sq km of abalone farms were affected, causing about A$525m in lost production.Explaining the toxic effectsMicroalgae can damage the gills of fish and shellfish, preventing them from breathing. This is the main cause of death. But some studies have also found damage to the gastrointestinal tracts and livers of fish.Tests using fish gill cells clearly show the dramatic toxic effect of K. mikimotoi. When the fish gill cells were exposed to intact K. mikimotoi cells, after 3.5 hours more than 80% of the fish cells had died.Leafy seadragons were among the dead sea creatures that washed up on South Australian beaches. Photograph: Anthony RowlandFortunately, the toxin does not persist in the environment after the K. mikimotoi cells are dead. So once the bloom is over, the marine environment can recover relatively quickly.Its toxicity is partly due to the algae’s production of “reactive oxygen species”, reactive forms of oxygen molecules which can cause the deaths of cells in high doses. K. mikimotoi cells may also produce lipid (fat) molecules that cause some toxic effects.Finally, a very dense bloom of microalgae can sometimes reduce the amount of dissolved oxygen in the water column, which means there is less oxygen for other marine life.The human health effects are not very well known but probably relate to the reactive oxygen species being an irritant.K. mikimotoi cells can also produce “mucilage”, a type of thick, gluey substance made of complex sugars, which can accumulate bacteria inside it. This can cause “sea foam”, which was evident on beaches last week.Unanswered questions remainA question for many people is whether increasing water temperatures make blooms of K. mikimotoi more likely.Another concern is whether nutrient runoff from farms, cities and aquaculture could cause more harmful algal blooms.Unfortunately, for Australia at least, the answer to these questions is we don’t know yet. While we know some harmful algal blooms do increase when nutrient runoff is higher, others actually prefer fewer nutrients or colder temperatures.We do know warmer water species seem to be moving farther south along the Australian coastline, changing phytoplankton species abundance and distribution.While some microalgal blooms can cause bioluminescence that is beautiful to watch, others such as K. mikimotoi can cause skin and respiratory irritations.If you notice discoloured water, fish deaths or excessive sea foam along the coast or in an estuary, avoid fishing or swimming in the area and notify local primary industry or environmental authorities in your state.

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