Common questions about microplastics and our work on the St. Johns River.
Yes, Microplastics MATTER.
Single use plastics traveling into our river is generally considered "bad," but why is it bad other than making our water dirty? In short, these plastics cause microplastics to be in our river, and microplastics have ripple effects. They can be detrimental to the health of humans, alter soil structure and plant growth, reduce marine phytoplankton activity, absorb and carry pollutants with them up the food chain, and even influence the weather. The fact that particles smaller than a sesame seed can do this is astounding, and they will continue to unless we stop them.
They are tiny pieces of plastic, most times invisible to the naked eye. They are categorized as smaller than 5 millimeters (the size of a sesame seed), and they circulate globally through water, air, and food. They pose environmental and health concerns.
Primary microplastics are made for industrial use, such as microbeads in face washes and laundry powders. Secondary microplastics come from single-use plastics (for example plastic bags) when they are exposed to the sun and waves, and small pieces break off over time.
Similarly to how many seeds travel, microplastics travel through water, air, and animals. When animals consume microplastics in the water, they travel up the food chain and can eventually reach humans. Researchers are still studying what happens when people are exposed through ingestion, inhalation, or skin contact. A 2024 study published in the New England Journal of Medicine found that people with microplastics and nanoplastics detected in artery plaque had a higher risk of heart attack, stroke, and death compared to those without — one of several studies now examining possible health effects. Early research has also detected microplastics in human blood and other tissues, but scientists are still working to understand what this means for long-term health.
Our river is very slow moving, with very few elevation drops, which causes very slow circulation. Most microplastics sink and accumulate. The northernmost 100 miles of the river act as a tidal estuary. Ocean tides and strong north winds push against the river's current, sometimes causing it to flow backward or stand still. This trapping mechanism forces microplastics to settle into the sediment. This somewhat mirrors the phenomenon of garbage ocean patches, which accumulate in the ocean because of currents.
Many governments and environmental groups see microplastics as an "emerging issue," especially compared to issues like algae blooms. This does not mean it's unimportant. To the contrary, the world of conservation is huge, meaning different groups can work on different issues at the exact same time, in a group effort that ensures we protect the planet in all aspects instead of waiting for the next big crisis. "Emerging" does not mean it's a distant issue either, it means that right now is the best time to stop it. It is much easier to stop microplastic now before it becomes an even more urgent issue than it already is.