Microplastic fragment and fiber contamination of beach sediments from selected sites in Virginia and North Carolina, USA

摘要

Microplastic particles (< 5 mm) constitute a growing pollution problem within coastal environments. This study investigated the microplastic presence of estuarine and barrier island beaches in the states of Virginia and North Carolina, USA. Seventeen sediment cores were collected at four study sites and initially tested for microplastic presence by pyrolysis-gas chromatography-mass spectrometry. For the extraction, microplastic particles were first separated from the sediment using a high-density cesium chloride solution (1.88 g/mL). In a second step, an oil extraction collected the remaining microplastic particles of higher densities. Under the light microscope, the extracted microplastic particles were classified based on their morphologies into fragments and fibers. Raman microspectroscopy chemically identified a subset of microplastic particles as polypropylene, polyethylene terephthalate, poly(4-vinylbiphenyl), polystyrene, polyethylene, and nylon. The results show a concentration of microplastic particles (1410 +/- 810 per kg of dry sediment) even in protected and ostensibly unpolluted estuarine and beach sediments of Virginia and North Carolina.