Heavy metal pollution in children playgrounds in Hong Kong and its health implications

Due to the scarcity of land in Hong Kong, most of the children playgrounds are being built on marginal lands which may be subjected to serious atmospheric emission. Hence, children playing in these playgrounds are exposed to a potential health risk. The aim of this study was to evaluate heavy metal pollution in children playgrounds using surface dusts and soils as indicators. Surface dust and soil samples were collected from seven selected playgrounds with different levels of traffic volume and urban development for the determination of total Cd, Cu, Pb and Zn concentrations. The mean Cd, Cu, Pb and Zn concentrations of surface dusts were 2.63, 201, 302 and 1517 mg kg(-1) respectively, whereas for soils they were 2.30, 28.4, 195 and 237 mg kg(-1). The results indicated elevated concentrations of Cd, Cu, Fb and Zn in both dust and soil samples especially for those samples collected from busy commercial and industrial areas i.e., Mei Foe, Tsim Sha Tsui and North Point. Surface dusts were enriched relative to soils in each metal, on average, by factors ranging from 1.1 to 7.1. The metal contents in dust and soil samples were significantly correlated with traffic volume. Significant correlations were also noted among all the metals studied indicating that Pb and Zn in the samples may be due to the same source i.e., automobile. The soil Pb and Zn contents of Mei Foo and North Point were higher than the investigation level of the Dutch Criteria for these two metals which indicated that further investigation is required to confirm their health hazard on children playing in these playgrounds.