Abstract:

The research investigated the distribution and correlation of heavy metals in groundwater of sewage irrigation area in Pearl River Delta. 14 groundwater samples and five surface water samples were collected in August 2008, and the groundwater samples were filtrated through 0.45 μm membranes in the field site. The results showed that the amount of Ni and As in some groundwater samples exceeded the standards for drinking water quality in China, and the over standard rates were 14.3% and 42.9%, respectively. The concentration of Cr, Pb, Cu, Zn, Se and Cd in all groundwater samples was lower than the upper limits for drinking water quality in China. There was a good relationship between the contents of these eight heavy metals in surface water, industrial wastewater and groundwater of sewage irrigation area. Furthermore, there was a significant or remarked significant positive correlation between Cd, Cu, Zn and Pb in groundwater, a remarked significant positive correlation between Cu and Pb in groundwater, a remarkable positive correlation between Cu and Cd in groundwater, a significant positive correlation between Cr and Ni in groundwater and no significant correlation between As and other seven heavy metals. The result of cluster analysis showed that these eight heavy metals can be divided into four categories: Pb and Cu;  Se, Cd, Ni and Zn; Cr； As. Pb and Cu had a good similarity with Fe. Se, Cd, Ni and Zn had a good similarity with Mg²⁺. Cr and HCO^－₃ had a good similarity, and As and SO^2－₄ had a certain similarity.

Key words: Pearl River delta, sewage irrigation area, groundwater, heavy metals