A few weeks ago, I summarized information from a study about the alarming amount of microplastics created when water is shaken in plastic baby bottles. Consumers have understood that plastics used for food and drink containers and many other items are resilient and unchanging. However, studies continue to show that some microplastics are released from most plastic products. Since there continues to be an increase in the production of plastics, living systems are increasingly exposed to these non-biodegradable materials and their chemical additives. 

Recently, my research group observed an even greater degree of disintegration of plastics in the water. We have shown that plastics in water and in the presence of certain other compounds form smaller micro and nanoplastics when shaken. We mixed a piece of polyethylene from a milk bottle with a small amount of kerosene in water. After shaking in the same manner as mixing baby formula, plastic pieces less than 10 micrometers in size formed. This was observed as cloudiness and was proven to be tiny pieces of polyethylene. We have shown that this behavior applies to many different plastic materials using substances other than kerosene. 

At home, I mostly emptied the PET plastic bottle containing vegetable oil except for some residual oil. I filled the bottle about a third full with water, replaced the cap, and shook the bottle for about 20 seconds. I let the mixture settle, and the small amount of vegetable oil left in the bottle floated to the top of the water. The water was cloudy (and remains cloudy), signifying the presence of nanoplastics. 

This work is now published as an open-access paper (https://www.sciencedirect.com/science/article/pii/S0269749122013859?via%3Dihub). Many researchers are more concerned with the interactions of the smaller nanoplastics in the human body, which have the ability to cross membranes and disrupt biological functions.  The ease of formation of nanoplastics in water should be added to the list of reasons to reduce plastic use.

Julie Peller, Ph.D., is an environmental chemist (Professor of Chemistry at Valparaiso University ). Julie has been writing a weekly column for the past ~6 years called the Green Junction and is helping to move the call of Laudato Si to action forward. Her Research Interests are advanced oxidation for aqueous solutions, water quality analyses, emerging contaminants, air quality analyses, Lake Michigan shoreline challenges (Cladophora, water, and sediment contaminants), and student and citizen participation in environmental work.