Distribution, enrichment and sources of heavy metals in surface sediments of Hainan Island rivers, China

Heavy metal concentrations in 36 samples of surface sediments from Hainan Island rivers were determined to evaluate the level of contamination in the region. Heavy metal concentrations (mg/kg) of Hainan Island rivers were in the range of 0.01-0.58 mg/kg for Hg, 0.09-0.70 mg/kg for Cd, 1.80-36.87 mg/kg for As, 15.33-69.32 mg/kg for Pb, 4.46-150.89 mg/kg for Cu, 6.64-104.95 mg/kg for Cr and 22.11-199.11 mg/kg for Zn. Contamination indices including contamination factor, enrichment factor, and geoaccumulation index, and multivariate statistical analyses indicated that Wenlan River was relatively at a considerable pollution level; Nandu, Changhua, Lingshui, Wanquan and Zhubi rivers were at a low-to-moderate pollution level; Beimen and Ningyuan rivers were at a level of relatively low pollution. Principal component analysis indicated that Cd, Pb, Cr and Zn were predominantly sourced from anthropogenic sources; whereas, Cu, As and Hg were from lithogenic sources. This study would be helpful for sustainable land use and marine management in the region.