The Levels and Risks of Heavy Metals, Polycyclic Aromatic Hydrocarbons, and Polychlorinated Biphenyls in Hun River in Northeastern China

The Hun River Basin is one of the most important heavy industrial and agricultural production bases of China. Its pollution level has exerted negative effects on human health. In order to investigate pollution levels and estimate the cancer risk of water in the river, water samples were collected in both the flood and dry periods. Pollution indicators were detected in terms of heavy metals, polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs). The mean concentrations of chromium (Cr), cadmium (Cd), PAHs, and PCBs were, respectively, 7.96 mu g/L, 0.08 mu g/L, 2597.22, and 21.21 ng/L in the flood period, and 19.02 mu g/L, 1.10 mu g/L, 1212.91, and 16.69 ng/L in the dry period. The concentrations of heavy metals were lower in the flood period than those in the dry period. However, in the meantime, contamination by PAHs and PCBs was heavier in the flood period than those in the dry period the most abundant being four ring PAHs and three-Cl PCBs in the flood period, and three-ring PAHs, four-ring PAHs, and four-Cl PCBs in the dry period. The carcinogenic contribution rate was in the order: Cr > PAHs >PCBs > Cd. The mean lifetime value of carcinogenic risk was 8.200 x 10(-4), which indicated that there was a risk of cancer associated with drinking Hun River water.