Plastic Consumed by Fish Hooks Researchers to Probe Deeper

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By Amena H. Saiyid

Swallowing small pieces of plastic in water found in lakes, rivers and oceans may harm fish and other aquatic organisms. How harmful is a question that scientists say needs further research.

The global production of plastics in 2014 was 311 million tons. In 2010 alone, between 4.8-12.7 million metric tons of plastic found their way into our oceans, according to a 2016 United Nations Environment Programme report.

“Plastics in the waterways are increasing. There is reason to believe that these tiny pieces of plastics could have a substantial impact on the natural environment and on the aquatic life,” said Sherri Mason, an environmental chemistry professor at the State University of New York at Fredonia whose research uncovered microplastics inside 25 species of Great Lakes fish including perch and trout.

Mason told Bloomberg BNA the risk of chemical exposure posed to fish by swallowing plastics that adsorb pollutants on their surface like a sponge is something that requires further examination, funding and attention at the national level.

The Environmental Protection Agency’s white paper summarizing the latest research on the risks to aquatic life from ingesting plastics provides the national attention the issue warrants, Mason said.

The paper acknowledges the potential for plastics to be a source of contaminants, from both the chemical constituents of the manufactured plastic itself and contaminants sorbed onto the surface of plastics in the aquatic environment. Given this potential, the EPA said “there is growing concern about the toxicological impacts of chemicals associated with plastics on aquatic organisms, as well as, aquatic-dependent wildlife, such as seabirds.”

More Research on Harm

The EPA said the following questions need to be resolved to understand the extent of harm posed by plastic pollution in water:

  •  To better understand the fate of chemicals both sorbed to and in plastics under differing environment conditions and within an organism after ingestion;
  •  To research the relative role plastics play in chemical contaminant transfer to the tissues of organisms compared to other exposure pathways (aqueous dermal exposure and ingestion from natural prey);
  •  To understand the relative impacts of physical and chemical effects of ingested plastic particles on a wide range of organisms;
  •  To determine whether the relatively high surface area of nanoplastics compared to microplastics and their potential to permeate membranes with increased retention time may increase their toxicological risk to organisms.
“Yes, macroplastics are bad,” but “still missing is the answer to half of the ecological risk question: What is the exposure in the field?” said G. Allen Burton Jr., a professor with the Natural Resources and Environment and Earth and Environmental Sciences departments at the University of Michigan at Ann Arbor. He has questioned the rush of environmental scientists to correlate harm with ingestion of plastics, both smaller and larger than 5 millimeters in size.

He pointed to the Baldwin study that documented the exposure concentration of microplastics in Great Lakes fish, but failed to mention that microplastics reported per cubic meter equates to 1,000 liters.

“This paper supports the numbers I came up with and means the exposure to microplastics in the worst areas cannot be an ecological risk,” Burton told Bloomberg BNA.

Mason, who was a co-author of the Baldwin paper, is a bit perplexed by Burton’s critique of scientists who want to investigate the linkage between microplastics and chemical exposure. On the one hand, Burton said there’s no evidence that microplastics are harmful, a conclusion that Mason said would require funding and studies to prove. On the other hand, Burton criticizes scientists for wanting to study whether there is a potential for harm, Mason said.

“If there isn’t data to indicate there is an ecological consequence, there also isn’t data to indicate there isn’t,” Mason said. “We need funding and time to do those studies.”

The San Francisco Estuary Institute, an ecosystem and aquatic science nonprofit that helps implement the bay area’s regional water quality monitoring program, plans to examine the extent of microplastic pollution problem in the Bay and surrounding ocean through a two-year grant they have just received, Rebecca Sutton, the institute’s senior scientist, told Bloomberg BNA.

Not in a Marine Environment

The American Chemistry Council’s Keith Christman agrees that plastics don’t belong in a marine environment, though as marketing director for plastic products he is quick to point out to Bloomberg BNA the vital role plastics play in society.

Christman pointed to the 2016 Koelmans’ study, which the EPA paper also highlighted, that discusses the many exposure pathways to which marine animals are exposed to persistent organic pollutants. This study finds that bioaccumulation of chemical pollutants found on plastics inside aquatic life is one of many pathways by which exposure can occur. The other pathways include direct chemical exposure via water, sediment, or ingestion of contaminated prey.

The EPA maintains throughout the paper that the challenge with field studies, such as the Koelmans’ study is that it is difficult to definitively link bioaccumulation of chemicals to the ingestion of plastics versus other uptake pathways.

Limited Evidence

The UNEP too in its 2016 report on marine plastic debris and microplastics concluded from the limited evidence present that the microplastics in seafood do not currently represent a human health risk “although many uncertainties remain” about the potential risk that such products could pose.

The plastics industry is aware of the potential that bioaccumulation of chemicals could pose, and has taken steps both globally and domestically to reduce plastic pollution, according to Christman.

In 2011, the Plastics Industry Association as well as the American Chemistry Council joined 67 other plastics groups and allied industry associations in 35 countries in signing a global declaration to voluntarily take steps to reduce marine litter, including plastics. Christman said the American Chemistry Council has been involved in the international state-of-the-science report on microplastics.

“The industry itself is constantly involved in research around innovation, working to reduce impacts of plastics and improve their environmental performance, making them more recyclable,” Christman said.

The EPA made it very clear to Bloomberg BNA that it has no plans for attempting to regulate plastics, saying its voluntary Trash-Free Waters is working well in states. The program that works in concert with local officials and volunteers is designed to reduce the huge volumes of trash entering the nation’s waters. The agency dispelled all questions about its intention, saying the paper’s goal was to provide the latest research, and that’s it.

The Center for Biological Diversity, which successfully advocated for a federal legislation in 2014 to phase out the use of plastic microbeads in face washes, toothpastes, said the key is to eliminate the use of plastic altogether because plastic pollution is turning the ocean into a “toxic mess.”

“It’s horrible,” said Abel Valdivia, the center’s ocean scientist, told Bloomberg BNA. “We agree with the EPA that more research into ocean plastic pollution is needed. But we also must attack this problem now by choosing tap water over plastic water bottles and taking steps to keep microplastics found in clothing and beauty products out of our oceans.

To contact the reporter on this story: Amena H. Saiyid in Washington at asaiyid@bna.com

To contact the editor responsible for this story: Larry Pearl at lpearl@bna.com

For More Information

An EPA state-of-the science white paper on the chemical toxicity of plastic pollution on aquatic life is available at https://www.epa.gov/sites/production/files/2016-12/documents/plastics-aquatic-life-report.pdf

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