Microplastics, tiny plastic particles found in everyday products from face wash to toothpaste, are an emerging threat to health and ecology, prompting a research team to identify what keeps them trapped in stream ecosystems. Everyday actions like washing synthetic clothing and driving, which wears down tires, contribute to an accumulation of microplastics in environments from city dust to waterways. These plastics often carry toxic chemicals that can threaten the health of humans and wildlife.”We are the key source of microplastics,” said Shannon Speir, assistant professor and researcher in the Dale Bumpers College of Agricultural, Food and Life Sciences, and for the Arkansas Agricultural Experiment Station, the research arm of the University of Arkansas System Division of Agriculture.