Pictured: Katherine Landwehr gets ready to test a biodiesel sample
In a world being urged to embrace renewable options, biodiesel fuels – made from plants and animal byproducts – are increasingly touted as a greener, cleaner choice than traditional diesel.
But world-first evidence being produced by a The Kids Research Institute Australia and Curtin University researcher has raised questions about the health impacts of these seemingly friendly products.
Dr Katherine Landwehr’s work has, for the first time, shown not all biodiesel fuels are equal, with the exhaust from some – especially biodiesel made from beef fat – producing more toxic health effects than others.
“Prior to my research, all biodiesel was treated as interchangeable and there was virtually no consideration of its potential to impact health,” Dr Landwehr said.
“My work has shown not only that there is a spectrum of toxicity depending on the type of oil or fat used to make the biodiesel, but that some types are even more toxic than mineral diesel – a known carcinogen.”
Her findings have revealed even short exposures to diesel and biodiesel exhaust can have toxic effects.
In a study published this year, mice exposed for just two hours a day for eight days to diesel and beef tallow biodiesel exhaust, at levels typical of a mining setting or alongside a busy road, exhibited a dampened immune response and showed evidence of lung damage and ‘hyperreactivity’ – a response similar to that seen in asthma.
“We saw a decrease in some types of immune cells and immune cell signalling, which suggests immune dysregulation in the lungs after breathing in exhaust for this long – and that’s a concern,” Dr Landwehr said.
“They’re effectively using up their reserves of immune function to handle the exhaust, which means they are less likely to be able to deal in the normal way with, say, a virus or cancerous cells that may appear.
“Exposure to tallow diesel also led to some airway damage. Our imaging found slightly increased space in the lungs, which suggests some alveolar deterioration – the same kind of irreversible damage you see from longterm cigarette smoking.”
Conversely, mice exposed to canoladerived biodiesel displayed less severe negative effects in the lungs and immune cells – evidence which backs up Dr Landwehr’s earlier findings that canola biodiesel consistently produces fewer toxic side effects, while beef tallow produces the most.
Dr Landwehr said the next step would be to explore better biodiesel regulations, including labelling.
“Current regulations are more about how biodiesels impact vehicle engines and how well they lubricate the fuel, rather than broader impacts. We urgently need to start paying more attention to the health impacts of these fuels.”
Miners breathe more easily thanks to research
Researcher Katherine Landwehr’s world-leading exhaust toxicology research, being conducted at Curtin University and the Wal-yan Respiratory Research Centre – a powerhouse partnership between The Kids Research Institute Australia, Perth Children’s Hospital and the Perth Children’s Hospital Foundation – has already led to policy changes aimed at protecting the health and safety of Australian workers.
In 2019 she was part of a working group commissioned by the WA Department of Mines which found diesel exhaust concentrations in underground mining exceeded safe levels.
The group’s report – written by Dr Landwehr as part of her PhD thesis – led directly to the establishment of occupational diesel exhaust limits in mining in Western Australia in 2020, with similar limits introduced in New South Wales in 2021.
“Prior to this, Australia had no occupational limits for diesel exhaust exposure, despite it being an acknowledged carcinogen since 2012,” Dr Landwehr said.
Diesel-powered machinery is ubiquitous in the mining industry, so these changes have the potential to benefit nearly 200,000 workers every year in WA and NSW, by reducing the amount of diesel exhaust they’re exposed to daily.
The Australian Council of Trade Unions wants to see regulators go even further, using Dr Landwehr’s research in a 2020 submission to Safe Work Australia calling for the establishment of national occupational diesel limits across all sectors.
Dr Landwehr has also presented her work to WA government departments and mining professionals, discussing which oil crops make the best biodiesel and outlining the devastating health effects that can follow occupational exposure to diesel exhaust – including cardiovascular disease and lung, bladder and brain cancers.