Why Should I Care About Microplastics?

Microplastics come from larger plastic items, breaking down to sizes so small we cannot see them with our bare eyes. These microplastics can be found everywhere, ranging from our oceans to even the food that we eat. Not only are they everywhere, but they are so hard to completely break down that they can last our entire lifetime. The real problem is that these tiny pieces can excrete harmful chemicals into their surroundings. Their small sizes makes them easily ingestible, making their way into wildlife and humans alike. This means that said chemicals can be transferred from the microplastics to their hosts.

The Salton Sea

The Salton Sea was once a beautiful lake surrounded by resorts. Now, after decades of pollution and the decrease of water levels, it is filled with toxic metals and runoff from neighboring agricultural sites. Due to recent findings of microplastics in agricultural runoff, this raises three important questions : are microplastics being found in high amounts in the Salton Sea? If so, what types of microplastics are they? Lastly, are these microplastics coming from neighboring agricultural areas?

Assessing for Microplastics

We collected water samples from five sites, including drainage canals, clean irrigation canals, a main source of runoff into the Salton Sea called the Alamo River, a still ditch near the river, and the Salton Sea. These sampling sites can be seen in the image below. The water was filtered and, using different microscopes, the types of plastics that were found were categorized. Thousands of microplastics were found and categorized their possible sources, such as polypropylene, which is a common plastic used for every day materials like takeout food containers.

What Did We Find?

We were quite shocked by what we found! We saw that the Alamo River, which collects water from multiple agricultural sites, had the highest microplastic count. This wouldn’t have been too surprising if we hadn’t also found that the Salton Sea had the lowest amount of microplastics out of all the sites. On top of this, the irrigation water that was supposed to be clean had more microplastics than the water that came from agricultural sites! In terms of which microplastics we found, we saw that polypropylene, a common plastic used in agriculture, was the most common microplastic found throughout our samples.

The irrigation water having more microplastics than the water coming from agricultural sites hints that the irrigation water might be bringing microplastics into the fields. This could lead to the microplastics settling into the dirt of these areas.

Our Data

So What Now?

Our study suggests that the soil in agricultural fields might be working like a filter, trapping microplastics before they can make their way into the Salton Sea. While this is good news for the Salton Sea, this brings up the question of what happens now that these microplastics are getting stuck in the soil where food grows?

Our research suggests a need for better control and management of water sources and plastics use in agricultural areas, as this might lead to problems down the road if it is not addressed now. Microplastics haven proven to be a serious issue, and understanding them is how we can best prevent this environmental concern.

Did you enjoy this post? Do you want to learn more about the growing issue of microplastic pollution in the environment? Check out this study on the presence of microplastics in commercial fish in Malaysia!