Heavy Metal Contamination in Urban Soils II Comparison of Urban Park Soils Between Two Cities with Different City and Industrial Activities

摘要

A comparative investigation on the state of heavy metal contamination in park soils of two cities with different city and industrial activities was carried out. Sakai and Kishiwada, both situated in southern Osaka Prefecture, were chosen as the investigated cities which had similar natural conditions but different human activities. Park soils were regarded as suitable sites for the investigation of heavy metal problem in urban environments. Samples were taken at 34 parks distributed widely in urban area in each city. Zinc level in park soils in Sakai was notably high and showed an increasing trend among areas in agreement with the extent of general air pollution in the areas. In Kishiwada, an increasing trend from inland area to near the shore was observed in zinc level. In the distribution of copper concentrations similar patterns as, but less significant than, in the case of zinc were observed in both cities. In manganese distribution rather different patterns from above two metals were found, and soils with higher manganese content were located irregularly in inland areas. Comparing the corresponding mean values of metal contents in soils in each city, it was considered that metal contamination in urban soils in Kishiwada, with less human activities than Sakai, had not so progressed as far in Sakai.