Contamination by toxic substance of soil and groundwater originating ina great earthquake disaster

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The possibility of heavy metal contamination of urban park soils caused by a big fire originating in the Great Hanshin Awaji Earthquake was examined. The behavior of heavy metals in park soil of the stricken area and the change in time of sorption forms of heavy metals were studied with various extraction methods. The following conclusions were obtained :1. Some heavy metals temporally changed their sorption forms from exchangeable forms to hydrochloric acid extraction forms, and finally to the forms unextractable even by nitric acid.2. Zn and Sb were nominated for the element spread during the earthquake disaster, because they showed high concentration in soil in the Nagata district where the influence of the big fire was significant. The highest concentrations of Zn and Sb were some times larger than those in Kyoto or Yokohama respectively. Some of the other heavy metals showed another possibility of their contamination by the normal urban activities.3. The correlation coefficients of the couples of elements, I.e. Cr-Cu, Cr-Pb, Mn-Co, Co-Cu, Co-Zn, Co-Pb Cu-Cd, and Cu-Pb, showed temporally decreasing trends, however, those of the couples of Mn-Cu, Mn-Zn, Mn-Cd, and Mn-Pb showed temporally increasing trends. This meant that the slow repartitioning of those metals in soil caused the changes of correlation coefficients of them. The cluster analyses also showed this possibility clearly.4. The results of this study could be compared to the reported investigation results about air and rain.