An Investigation into Heavy Metals Pollution in a Landfill of Guangzhou

Abstract

The aim of the present study was to investigate the pollution situation of a closed landfill located in Likeng village, Guangzhou. Soil samples in different depths were collected from the studied area. Among of them, total 108 samples (0~10 cm) of surface soil were analyzed for Cd, Cr, Hg, Ni, Pb and Zn investigation. The samples were digested with HNO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> and HF and HClO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> . The concentrations of Cd, Cr, Hg, Ni, Pb and Zn were analyzed with ICP-MS. The chemical analysis showed that the metals concentration were varied over a range of 0.023~0.31 mg/kg for Cd, 15.8~702.6 mg/kg for Cr, 0.007~1.77 mg/kg for Hg, 0.6~79.5 mg/kg for Ni, 10.1~82.7 mg/kg for Pb, and 17.4~247.1 mg/kg for Zn, with an average concentration of 0.072 mg/kg, 77.1 mg/kg, 0.091 mg/kg, 20.5 mg/kg, 31.6mg/kg and 60.1mg/kg respectively. The average concentrations of Cr, Hg, Ni and Zn were higher than the background values of soils in Guangdong province. In particular, the average concentrations of Cr and Ni were even higher than the average values of polluted soils in suburb of Guangzhou. The data indicated that the soils in the studied area had been polluted by heavy metals. Further more, the distribution of heavy metals were varying in different areas. The metal concentrations of Hg and Cd were higher in the agricultural land near-by the landfill than others. But there was no evidence to show that the agricultural land had been polluted heavily by now. Moreover, the metal contents of Cr, Ni and Zn in the soil samples were higher than other metals, with significantly positive correlation each other, especially in the areas of L1, L2 and L9, the south-east part of the landfill. From the fact infers an unknown fact that some hided geo-damages might exist in the landfill site, which allowed leachate diffusing to soils and underground water causing potential dangerous to resident's health. The whole landfill site would become a huge dangerous source of pollution if no appropriate action were taken to solve the problems. So it is necessary to take a further research on remedial actions, protection measures or scientific problems on related fields.