Researchers have long known that plastic pollution reaches the ocean. But how much plastic is trapped, and where, before it reaches the ocean is far less understood.

As professors of environmental engineering, geography and environmental studies, and oceanography at Penn State, we recently led studies mapping how microplastics move through bodies of water across Pennsylvania. What we found was striking: Microplastics are nearly everywhere, their concentration in sediment has been doubling every 20 years, and some of the most common types are among the most toxic.

Plastic is everywhere, including inside us

Since the 1950s, global plastic production has doubled about every 20 years. The world now produces over 500 million tons annually - roughly the combined weight of every person on Earth.

Today, more than half of plastic waste ends up in landfills, and less than one-tenth is recycled globally. The U.S. generates over 48 million tons of plastic waste annually, and approximately 86% is sent to landfills. The domestic recycling rate is roughly 5% to 6%, making the U.S. a leading producer of plastic pollution. The rest enters the environment, where it breaks down slowly, potentially over hundreds to thousands of years, into microplastics. These particles range in size from 5 millimeters, which is about the size of a pencil eraser, to 1 nanometer - for reference, a single strand of human hair is about 80,000 nanometers wide.

Microplastics are now found in the air, water, soil, food and living organisms, including humans. Microplastics enter the body through ingestion via what we drink, inhalation and skin contact. Studies have found........

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