BBC News reports birds living on river banks are ingesting plastic at the rate of hundreds of tiny fragments a day, according to a new study. Scientists say this is the first clear evidence that plastic pollutants in rivers are finding their way into wildlife and moving up the food chain. Pieces of plastic 5mm or smaller (microplastics), including polyester, polypropylene and nylon, are known to pollute rivers. Researchers at Cardiff University looked at plastic pollutants found in a bird known as a dipper, which wades or dives into rivers in search of underwater insects.