For many Mainers, the defining characteristic of our community is our relationship with the sea. It is a source of livelihood, of food, of recreation and of sanctuary. But today we are facing a new and very serious threat: plastics.

Most of us have heard about the plastic gyres twice the size of Texas in the Pacific Ocean, and how plastic debris is choking marine mammals, filling the stomachs of seabirds, and suffocating coral reefs. The fact is, our oceans today contain more than 8 million metric tons of plastic waste.

To Mainers, this may seem like a problem far from our shores. It is not.

What we didn’t realize is what we could not see: microplastics. Microplastics are the most abundant form of solid-waste pollution on Earth and are increasingly a threat to the citizens of Maine.

In the ocean, plastics degrade into particles smaller than 5 millimeters, which are consumed by marine wildlife and contaminate the food we eat. Invisible to the naked eye, microplastics pose a serious risk to ocean and human health, from the Pacific coast to the beautiful waters of Maine.

Since 2012, scientists from the Marine & Environmental Research Institute in Blue Hill have been monitoring plastics and microplastics in our local waters. Our findings were surprising to us, and they may surprise you.

Among the many reasons that Mainers should care about plastic pollution, here are three:

1. There are staggering amounts of microplastics in Maine coastal waters. Using a specially designed sampling method, we found an average of 27 plastic fragments in every liter of seawater from Blue Hill Bay — amounts typically found in heavily industrialized regions.

More surprising: The main source of the microplastics are consumer products coming through our wastewater — abrasive microbeads in beauty products released into sinks and shower drains, and microplastics from synthetic clothing released during washing. These tiny plastic fragments are too small to be captured by existing wastewater treatment processes and wind up in the ocean.

2. Microplastics are a threat to Maine seafood and the economy of Maine. In 2014, our researchers found large numbers of microplastic fragments in the tissues of oysters and mussels. Oysters had the highest number of fragments, averaging 177 pieces per oyster. Both rope-grown and wild-caught mussels had similar levels.

The presence of plastic fragments in Maine seafood could threaten the industry and the livelihood of thousands of Mainers.

3. People who eat Maine seafood could be ingesting microplastics. Not only are we eating plastic fragments, what is worse is that these plastics contain toxic chemicals that are harmful to our health. More than half of the plastics produced on a global level are associated with hazardous plasticizer additives and chemicals that cause endocrine disruption, reproductive effects, neurodevelopmental effects and cancer.

When marine animals ingest microplastics they can concentrate plasticizer chemicals as well as organic pollutants absorbed from the surrounding seawater. The bottom line is, if current trends continue, our seafood may be less of a healthy food choice than we think.

You may be asking, “What can be done?” We need to change. We must change our relationship with plastics, the convenience of plastics, our reliance on plastics in our daily lives. We need to think hard about our use of plastics and how we can reduce it by substituting safe materials. We also need and deserve protection from tougher legislation to protect human health and our environment from plastic pollution.

There are encouraging signs. Like cities across the country, many Maine communities are starting to take actions to reduce plastic pollution by seeking to ban the use of single-use plastic bags and re-use bags used in supermarkets. These and other social changes can and will make a difference.

Legislation to reduce plastic pollution in Maine is also moving forward. Our findings have helped alert legislators to the issues and inform policy decisions. In February, Maine’s Environment and Natural Resources Committee heard testimony on “An Act To Prohibit Synthetic Plastic Microbeads in Personal Care Products and Over-the-counter Drugs.” We presented our research findings, and the bill passed unanimously and became state law in March.

Later that month, we were again asked to testify on three new bills now before the committee. This legislation would impose a tax on single-use plastic bags, improve recycling and reduce plastic waste.

The possible crippling effect of microplastic pollution on the Maine seafood industry and the health of consumers drives us to accelerate our research efforts. The advancement of microplastics research is critical to the future health of our marine species and the health of people in Maine.

As Rachel Carson said, “The aim of science is to discover and illuminate truth.”

With a deeper understanding of microplastic pollution and its effect on people, marine life and the environment, we can all work together to protect our oceans and the people who rely on them.

Susan Shaw is director and founder of the Marine & Environmental Research Institute, and a professor at the School of Public Health, SUNY-Albany. Contact MERI at or 374-2135.