According to a new study by researchers from the National University of Singapore, plastic nanoparticles — extremely small plastic particles measuring less than 1 micrometer in size, the length of a typical bacterium — could pollute food chains and eventually affect human health.

The research found that these particles are easily ingested by marine organisms, with a risk of being transferred up the food chain, threatening food safety and posing health risks.

This news adds to the ever-growing problem of plastic pollution in the oceans. According to multiple reports, plastic in oceans is almost as proliferate as the sea life living in them, with possibly more than 150 million tons of plastic in the seas in total. Each year, about 8 million more tons are added.

Plastics do not degrade easily, and are usually broken down by the sun and movement from the ocean currents upon them, wind, and microbial action. Regarding the plastic specs that do break down into microfragments, they can be ingested by filter-feeding marine organisms, like barnacles, tube worms and sea-squirts, the researchers say.

"Using the acorn barnacle Amphibalanus amphitrite as a model organism, the research team demonstrated for the first time that nanoplastics consumed during the larval stage are retained and accumulated inside the barnacle larvae until they reach adulthood," a National University of Singapore release observed.

"We opted to study acorn barnacles as their short life cycle and transparent bodies made it easy to track and visualize the movement of nanoplastics in their bodies within a short span of time," said Samarth Bhargava, a Ph.D. student from the Department of Chemistry at the university, and the first author of the research paper.

Barnacles are found in all oceans, so they make for an easy test vehicle since plastics, too, are in all oceans, increasing the likelihood that the organisms will ingest them. For this specific project, researchers incubated the barnacle larvae in solutions of their regular food mixed with plastics that are "about 200 nanometres in size with green fluorescent tags."

The larvae were exposed to two treatment types: "acute" and "chronic." For the acute one, the barnacle larvae were kept for three hours in a solution that contained 25 times more nanoplastic than the oceans' current estimates. Under the chronic treatment, the larvae were exposed to a solution consisting of low concentrations of nanoplastics for up to four days.

The results found that the barnacles in both treatments ingested the plastic particles and had tiny particles of plastic distributed throughout their bodies. The team continued to find nanoplastics inside the barnacles throughout their growth into adulthood.

"Barnacles may be at the lower levels of the food chain, but what they consume will be transferred to the organisms that eat them," said marine biologist Dr. Neo Mei Lin in a statement.

Nanoplastics don’t necessarily enter the oceans as small microparticles. For example, during the 2011 International Coastal Cleanup, volunteers in multiple countries’ shorelines picked up every kind of trash imaginable. They kept a tally of the most common items that washed up on shore. Among them were plastic lids and bottles, straws and cups, plates, knives and spoons.

"Our volunteers picked up enough food packaging for a person to get takeout for breakfast, lunch and dinner every day for the next 858 years," Vikki Spruill, Ocean Conservancy’s former president and CEO, said at the time. "Ocean trash is human-generated, preventable and one of the biggest threats to our ocean and waterways."

According to the National Ocean Service, microplastics come from a variety of sources, including microbeads, a type of microplastic-manufactured polyethylene plastic that are “added as exfoliants to health and beauty products, such as some cleansers and toothpastes. These tiny particles easily pass through water filtration systems and end up in the ocean and Great Lakes, posing a potential threat to aquatic life.”

Plastic microbeads first appeared in personal care products more than five decades ago and replaced many natural ingredients; however, on Dec. 28, 2015, President Obama signed the Microbead-Free Waters Act of 2015, banning plastic microbeads in cosmetics and personal care products.

Regarding the National University of Singapore research, the scientists admitted that more research is required to better understand how plastics may affect long-term effects on marine ecosystems.

They are now looking into how nanoplastics affect other invertebrates, in order to understand the impact of plastics on marine ecosystems. The findings were first published online in the journal ACS Sustainable Chemistry & Engineering.