Plastics break into microplastics and move through the food chain. Inland lakes are common places where microplastics are deposited from a variety of sources, including highway runoff from road surfaces, brake pads, car tires, and road paint. Heavy metals and other contaminants have long been regulated pollutants in stormwater, but plasticizers and rubber-related contaminants are among a growing list of emerging contaminants. 6 p-phenylenediamine (6PPD) is used by every major tire manufacturer as an additive, which prevents cracking of the rubber in the tires. When 6PPD is released into the environment, it transforms into 6PPD-quinone (6PPD-Q). Multiple studies have identified aquatic toxicity of 6PPD-Q on several species of trout and salmon, for example.
In this study, the research team examined Michigan surface waters heavily impacted by road salt applications and highway stormwater runoff. ISTC scientists will analyze water samples for microplastics and perform polymer analysis to target tire wear and roadway paint particles. They will also develop methods to analyze 6PPD-Q and use them to measure 6PPD-Q in the Michigan surface water samples. ISTC’s partner, the Annis Water Resources Institute (AWRI), will examine biofilm abundance and taxonomic composition growing on different microplastics in the upper and lower levels of those same waters. Findings from this study will shed light on how biofilms grow on microplastics and change the microecosystems in urban lakes.
This project is expected to be finished by April 2023. Funds were provided by AWRI.