Impact of urbanization on nutrients and heavy metal pollution of Napahai Wetland, Shangri-La County, China

This study investigated the nutrients and heavy metal contents in water body and sediment of the Napahai Wetland during summer through fluorescence spectroscopy and inductively coupled plasma optical emission spectrometer analysis. Results indicated that most of the heavy metal contents in water body are derived from municipal sewage when the stream passes through the town center. The primary organic compounds in the water body of the Nachi River and the Napahai Wetland were hydrophobic acid, fulvic acid, and aromatic protein-like compounds. Cr, Ni, Cd, As, Pb, and V contents in wetland sediments significantly differ from sampling sites and depths, and varied in the following order: V > Cr > Ni > Pb > As > Cd. Principal component analysis showed that the distribution of heavy metals was primarily affected by urbanization and secondarily affected by other abiotic factors.