A study on distribution pattern of trace elements in chungnam coal mine area using factor analysis and GIS

Abstract

In order to examine the contamination levels of trace elements in stream sediments in the Chungnam Coal Mines area, stream sediment and water samples were collected and analyzed by ICP-AES. The pH of stream water was neutral or weak-alkaline because of low concentrations of sulfur from bedrock geochemistry, and the mobility of metal in stream sediments was considered to be low. To compile the drainage-based geochemical maps, catchment basins were calculated with aspects from DEM (Data Elevation Model) and stream-line segments. The constructed DEMs with 3 kinds of resolution were examined, and should be properly used for well-shaped and accurate catchment basins. The stream-line segments and sampling points were also considered as a target image for watershed segments and it was found that streamline segments as target images played a better role to reflect its catchment area than sampling points. It is important that geochemical database were manipulated to present the various phenomena. The factor analysis in R-mode was used to integrate geochemical data, and the input data for factor analysis were the concentrations of 12 trace elements in stream sediment and 3 anion concentrations and pH in stream water. Using maximum likelihood scheme, eingenvalues that explained about 90% of total variance were established and 4 factors were selected. The factors 1 and 2 indicated relative enrichment of trace elements, factor 3 were explained as human activities of residents and factor 4 were related with pH of stream water. The drainage-based geochemical maps with 4 kinds of factor scores were compiled. © 1998 Taylor & Francis Group, LLC.