Tons of Plastic Trash Enter the Great Lakes Every Year – Where Does It Go?

Subsequent simulationshave also found no evidence for a Great Lakes garbage patch. Initially this seems like good news. But we know that a lot of plastic is entering the lakes. If it is not accumulating at their centers, where is it?

Using our models, we created maps that predict the average surface distribution of Great Lakes plastic pollution. They show that most of it ends up closer to shore. This helps to explain why so much plastic is found on Great Lakes beaches: In 2017 alone, volunteers with the Alliance for the Great Lakescollected more than 16 tons of plasticat beach cleanups. If more plastic is ending up near shore, where more wildlife is located and where we obtain our drinking water, is that really a better outcome than a garbage patch?

Searching for missing plastic

We estimate that over four tons of microplastic are floating in Lake Erie. This figure is only a small fraction of the approximately 2,500 tons of plastic that we estimate enter the Lake each year.

Similarly, researchers have found that their estimates of how much plastic is floating at the ocean’s surface account for only around 1 percent of estimated input. Plastic pollution has adverse effects on many organisms, and to predict which ecosystems and organisms are most affected, it is essential to understand where it is going.

We have begun using more advanced computer models to map the three-dimensional distribution of plastic pollution in the Great Lakes.

Assuming that plastic simply moves with currents, we see that a large proportion of it is predicted to sink to lake bottoms. Mapping plastic pollution this way begins to shed light on exposure risks for different species, based on where in the lake they live.

According to our initial simulations, much of the plastic is expected to sink. This prediction is supported by sediment samples collected from the bottom of the Great Lakes, which can contain high concentrations of plastic.

In a real lake, plastic does not just move with the current. It also can float or sink, based on its size and density. As a particle floats and is “weathered” by sun and waves, breaks into smaller particles, and becomes colonized by bacteria and other microorganisms, its ability to sink will change.

Better understanding of the processes that affect plastic transport will enable us to generate more accurate models of how it moves through the water. In addition, we know little so far about how plastic is removed from the water as it lands on the bottom or the beach, or is ingested by organisms.

Prediction informs prevention

Developing a complete picture of how plastic pollution travels through waterways, and which habitats are most at risk, is crucial for conceiving and testing possible solutions. If we can accurately track different types of plastic pollution after they enter the water, we can focus on the types that end up in sensitive habitats and predict their ultimate fate.

Of course, preventing plastic from entering our waterways in the first place is the best way to eliminate the problem. But by determining which plastics are more toxic and also more likely to come into contact with sensitive organisms, or end up in our water supply, we can target the “worst of the worst.”

With this information, government agencies and conservation groups can develop specific community education programs, target cleanup efforts and work with industries to develop alternatives to products that contain these materials.

*SOURCE: This article was published in The Conversation. Go to ORIGINAL. 

2018 Human Wrongs Watch