Environmental assessment reveals high microplastic contamination in urban waterways, indicating significant particle flux into riverine ecosystems.
Key Points
To assess microplastic abundance, morphological distribution, and polymer composition in urban canals and quantify the associated ecological risk and discharge flux into peripheral rivers.
Sampled 30 sites (15 water and 15 sediment samples) across five major urban canals during the dry season to establish a worst-case contamination baseline.
Characterized particle morphology and surface degradation using scanning electron microscopy (SEM) and identified polymer types via Fourier-transform infrared spectroscopy (FTIR).
Evaluated environmental risk using the Nemerow Pollution Index (NPI) and estimated daily microplastic flux into downstream river networks.
Sediment microplastic concentrations ranged from 162 to 1188 items/kg, while surface water concentrations ranged from 13 to 185 items/L, dominated by fibers (33.93%) and fragments (22.99%).
Transparent particles (28.54% in water, 28.7% in sediment) and sizes between 0.5 and 1 mm were most frequent, with FTIR identifying polyethylene and polypropylene as dominant weathered polymers.
Canals scored between low and high contamination on the Nemerow Pollution Index, generating an estimated downstream flux of 50 to 189 billion microplastic particles per day.