The ingestion of debris we discard into aquatic environments, specifically pervasive plastic materials, by marine fauna is an unavoidable reality. A critical question arises: at what consumption level does this pose a fatal risk?
A recently published investigation, released on Monday, suggests that the tolerance threshold is remarkably low. For instance, avian species such as Atlantic puffins can succumb to ingesting an amount of plastic equivalent to less than three sugar cubes.
“This critical point is considerably smaller than our initial estimations,” commented Erin Murphy, a specialist in ocean plastics research affiliated with the Ocean Conservancy, a non-profit organization that spearheaded this research initiative.
The comprehensive report, disseminated through The Proceedings of the National Academy of Sciences, involved an in-depth analysis of necropsy records from over 10,000 marine organisms. The objective was to develop predictive models illustrating the diverse impacts of various plastic types on marine life and to pinpoint the dosage that leads to mortality.
“The scientific evidence is unequivocal,” stated Murphy in remarks to AFP. “It is imperative that we curtail our production of plastic materials. Enhancing collection and recycling infrastructures is essential, alongside concerted efforts to remediate existing environmental contamination.”
Academics meticulously compiled necropsy findings from numerous global studies and repositories. This data was specifically selected for instances where both the cause of death and the extent of plastic consumption were documented. The specimens generally consisted of animals that had been washed ashore or were incidentally captured.
Through sophisticated modeling, the researchers established correlations between the quantity of ingested plastic and the probability of fatality. This analysis considered both the total number of plastic items consumed and the volume of plastic relative to the capacity of the animal’s digestive system.
Furthermore, the study investigated the differential susceptibility of various animal groups to distinct plastic compositions. Seabirds, for example, demonstrated pronounced adverse effects from ingesting rubber and rigid plastic fragments.
The research indicated that as few as six small plastic fragments, each no larger than a pea, carried a 90% likelihood of proving fatal to these bird species.
Chelonians, commonly known as sea turtles, encountered significant peril from pliable plastic items, such as discarded bags.
These particular types of debris also proved exceptionally lethal to marine mammals, as did discarded fishing apparatus.
“In one instance, a whale’s stomach contained an object comparable to a three-gallon receptacle,” Murphy disclosed.
A substantial proportion, precisely half, of the individual animals examined belonged to species classified as threatened, vulnerable, or endangered.
The ‘Existential Threat’ Posed by Plastics
The authors of this study express hope that their findings will contribute to the enhancement or establishment of monitoring frameworks designed to mitigate plastic pollution.
“This research furnishes valuable insights into materials that may present particularly severe dangers, potentially warranting policy interventions,” Murphy explained, citing examples such as balloons and plastic bags.
The core focus of the investigation was on mortality events occurring shortly after gastrointestinal tract trauma, which represents only one facet of a more extensive environmental crisis.
It is crucial to recognize that this study addresses but a single component of a larger issue; the research did not encompass the chronic health implications of plastic-associated chemicals or the dangers of entanglement, both of which constitute significant hazards.
“The pervasive presence of plastic pollution represents an existential peril to oceanic fauna, and this assessment likely underestimates the totality of this threat,” Murphy asserted.
Kara Lavender-Law, an oceanography professor at the Sea Education Association, characterized the study as “remarkable” and “an exceptionally systematic and meticulous examination of existing data,” enabling a more precise comprehension and prediction of risks.
According to data compiled by the OECD, six million tonnes of plastic entered the global network of rivers, lakes, and oceans in the year 2019.
More recently, considerable attention has been directed towards the ubiquitous distribution of microplastics, which have been detected in the deepest oceanic trenches and found throughout the human body.
This research serves as a potent reminder that the problem of plastic contamination in our environment is multifaceted, Lavender-Law conveyed to AFP.
While a justifiable shift in focus towards micro- and nanoplastics, and from wildlife to human health, has occurred, she emphasized, “this does not negate the fact that the dangers posed by larger debris to larger animals remain a substantial concern.”
