Plastic Ingestion Risk
Modeling Wildlife Mortality Risk From Ingested Plastics
Widespread concern about plastics being swallowed by marine life—which can lead to their deaths—has fueled calls to determine how much and which types of plastic are riskiest for ocean wildlife. This has never successfully been done for a broad number of marine species until now.
Ocean Conservancy researchers and our academic collaborators around the world have developed scientific models that quantify the risk of marine wildlife deaths associated with the ingestion of macroplastics (greater than 5mm in size or the diameter of a pencil eraser), including many single-use plastic products that are commonly encountered in Ocean Conservancy’s International Coastal Cleanup®. These models are based on more than 10,000 necropsy datapoints and determine the likelihood of mortality for sea turtles, seabirds and marine mammals based on the amount of plastic found in their gastrointestinal tracts.
This research, published in November 2025 in the scientific journal Proceedings of the National Academy of Sciences (PNAS), represents the most comprehensive mortality risk assessment conducted for macroplastic ingestion to date, building extensively on previous work both in terms of the sample size of individuals considered, and the complexity of the modeling approach. Most important for policy, this work emphasizes the risk macroplastic pollution poses to animal health, and that risk varies by animal and plastic type. The significance of this study is underscored by its selection for the Cozzarelli Prize—awarded to just six papers out of more than 3,600 published in 2025 in the Proceedings of the National Academy of Sciences (PNAS). It was recognized as the top paper in Applied Biological, Agricultural, and Environmental Sciences.
Wildlife Impact Calculator
The Wildlife Impact Calculator is a free, publicly-available tool that illuminates the real-life positive impacts that cleaning up plastics from our coastlines can have on marine life. With the click of a button, the Wildlife Impact Calculator will quantify the direct, positive impact individuals can have on helping protect wildlife by participating in plastic pollution cleanups—helping to unleash broader engagement in the fight to reduce ocean plastic pollution and inspire more people to join the movement against it.
Our Plastic-Wildlife Impact Database contains information on macroplastic ingestion for more than 10,000 marine animals that informed our science. This database can be filtered and downloaded by location, species, and other variables of interest to users.
Together, the Wildlife Impact Calculator and Plastics-Wildlife Impact Database can help us understand how plastic pollution cleanups can benefit marine life and guide policies to reduce plastic pollution.
“The lethal dose varies based on the species, the animal’s size, the type of plastic it’s consuming, and other factors, but overall it’s much smaller than you’d think, which is troubling when you consider that more than a garbage truck’s worth of plastics enters the ocean every minute.”
“This study reminds us that plastic bags, fishing gear, and other items continue to threaten animals big and small.”