A nurdle, also called a pre-production plastic pellet or plastic resin pellet, is a plastic pellet typically under 5mm in diameter. Approximately 60 billion pounds (27 million tonnes) of nurdles are manufactured annually in the United States alone.
One pound of pelletized HDPE contains approximately 25,000 nurdles (approximately 20 mg per nurdle).
Nurdles that escape from the plastic production process into waterways or oceans have become a significant source of ocean and beach pollution, frequently finding their way into the digestive tracts of various marine creatures. Nurdles also can carry two types of micropollutants in the marine environment: native plastic additives and hydrophobic pollutants adsorbed from seawater. Concentrations of PCBs and DDE on nurdles collected from Japanese coastal waters were found to be up to 1 million times higher than the levels detected in surrounding seawater.