Could the plastic floating in our oceans be harming more than just marine life?

A new study suggests that people living in coastal areas with high levels of microplastics may be at a greater risk of disabilities affecting memory, mobility, and self-care.

Microplastics and Disability Risk in Coastal Areas

Tiny plastic particles in the ocean may be linked to a higher risk of disability among people living in coastal areas with high microplastic levels, according to a preliminary study released today (February 25, 2025). The research, set to be presented at the American Academy of Neurology’s 77th Annual Meeting (April 5-9, 2025), examines disabilities related to memory, thinking, mobility, and self-care.

While the study does not prove that microplastics cause disabilities, it identifies a significant association between high microplastic exposure and increased disability rates.

Marine microplastics are tiny plastic fragments — less than 5 millimeters in size — found in oceans and seas. They originate from broken-down plastic waste, as well as products like face scrubs, fishing nets, food wrappers, and takeout containers.

The Link Between Pollution and Health

“The environment can play a crucial role in our health, and factors such as pollution may impact a person’s risk of developing cognitive decline and other neurological disabilities,” said Sarju Ganatra, MD, of Lahey Hospital and Medical Center in Burlington, Massachusetts. “Our study found in coastal communities with higher levels of microplastics in the water, there were higher rates of disabilities that can affect a person’s life in many ways through thinking and memory, movement, and their ability to take care of themselves and live independently.”

The study looked at 218 coastal counties in the United States across 22 states.

Sorting Microplastics by Concentration

Researchers looked at marine microplastic levels across the counties, sorting them into four groups based on marine microplastic levels in the nearby ocean surface. Counties in the low group had zero to 0.005 microplastic pieces per cubic meter (pieces/m³) of ocean water, the medium group had 0.005 to one pieces/m³, the high group had between one and 10 pieces/m³ and the very high group had 10 or more pieces/m³. On average, counties with very high levels had more than 1,000 microplastic pieces/m³ of ocean water, while those with low levels had fewer than 10.

They then looked at the amount of disability among residents in these categories: memory and thinking, mobility, self-care, and independent living. Self-care disabilities include difficulty performing activities such as dressing, bathing, or getting around inside the home. Independent living disabilities include difficulty performing tasks such as managing finances, shopping, or using transportation.

Findings: Higher Microplastics, Higher Disabilities

Researchers found in counties with the highest levels of marine microplastics, the average prevalence of thinking and memory disabilities was 15.2% compared to 13.9% in counties with the lowest levels. The average prevalence of mobility disabilities was 14.1% in counties with the highest levels compared to 12.3% in counties with the lowest levels. The average prevalence of self-care disabilities was 4.2% in counties with the highest levels compared to 3.6% in counties with the lowest levels. The average prevalence of self-care disabilities was 8.5% in counties with the highest levels compared to 7.7% in counties with the lowest levels.

Adjusting for Other Health Factors

After adjusting for factors that could affect the rate of disability such as heart disease, stroke, depression, air pollution, and wealth and resource distribution, researchers found that counties with the highest marine microplastic levels showed a 9% higher rate of disability in memory and thinking, a 6% higher disability in mobility, a 16% higher disability in self-care, and an 8% higher disability in independent living when compared to counties with the lowest levels.

“These findings provide insights into how marine microplastics might affect brain health,” Ganatra said. “More research is needed to explore this connection further and examine the overall public health implications of microplastic pollution.”

Complex Factors at Play

Ganatra also noted, “The amount of plastic in different areas can vary due to ocean currents, which can carry and concentrate plastic in certain regions. Other factors, like population density, local waste management, and industrial activities, may also play a role. The reasons are complex and likely involve multiple environmental- and human-related factors working together, but this relationship needs further investigation to be fully understood.”

A limitation of the study was that it was a snapshot in time. Researchers did not follow coastal residents and marine microplastic levels over time.