Plastic pollution leaves even seemingly healthy seabird chicks with signs of cell rupture, damaged stomach linings and even brain damage “akin to Alzheimer’s disease.”
New research, published in the journal Science Advances, offers a look into the impacts of plastic pollution on a group of sable shearwater chicks on Lord Howe Island, a popular nesting site between Australia and New Zealand, revealing that even healthy-looking chicks are suffering from severe damage to multiple organs.
Less than a gram of plastic consumed translated to serious impacts, including a decline in a crucial protein known as brain-derived neurotrophic factor (BDNF) that was similar to levels associated with Alzheimer’s, Parkinson’s and dementia in other animals.
Plastics and lower BDNF “interrupts the development of [the chicks’] song control system,” Alix de Jersey, a University of Tasmania PhD student and lead researcher on the study, told the science research centre. De Jersey explained that it could have severe consequences for the shearwaters if they survive to adulthood.
“These birds don’t appear to be ill from the outside, but samples of their blood contain a variety of indicators of cell damage and death,” study co-author Dr Alex Bond, a bird expert from the UK’s National History Museum, explained. Finding evidence of brain damage as well was “surprising.”
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Over 20 percent of all plastic waste produced annually enters the environment as litter, creating plastic pollution on land and in the sea. Researchers focused their work on Lord Howe Island as its seabirds are among the most plastic contaminated birds on Earth, bringing back an average of 688,000 pieces of plastic every year, which is then fed to their chicks. These bits of plastic take up space in the digestive tract, leaving less room for actual food, and cause inflammation and scarring known as plasticosis, which can impact the birds’ growth, digestion and survival.
Researchers, aiming to get a more complete picture of the impacts of plastic, took blood samples from over 30 different young birds that showed no signs or symptoms of disease. The 90-day-old chicks were then divided into low and high impact groups depending on the amount of plastic ingested, which was assessed by flushing their stomachs and measuring the plastic content.
Blood analysis revealed a quarter of all protein expression was different between the groups, with high-impact chicks showing signs of damage to their kidneys, stomachs and other organs. Low levels of the antioxidant GPX3, the study warns, will have serious impacts for the sable shearwaters’ flight capabilities. Flying is a stressful experience for the body and without sufficient antioxidants to mitigate the damage, these birds may not be able to survive long-distance flights over the ocean.
While the findings are concerning for seabirds, the sable shearwaters should also be seen as canaries in the coalmine of what plastic pollution means for all species. The spectre of a plastic health crisis was raised by the World Economic Forum last month, as evidence mounts of unprecedented pollution levels in our bodies and the environment.
Research on humans has found microplastics throughout the human body, including evidence of nano- and microplastics in our brains. The full health impacts on humans are yet unknown, although studies point to increased incidence of heart attack, stroke and death – findings not out of line with the organ damage and altered blood chemistry seen in sable shearwaters.
