四国・高知県梶が森山頂の冬期降雨，降雪，樹氷及び雨氷中の鉛とカドミウム濃度

摘要

日本の国土の7割近くが酸素の生産，二酸化炭素吸収機能をはじめ土砂流出の防止，水源滴養，野生動物の生息地など多種多様な役割を担っている森林に覆われており，湿性降下物の酸性化だけではなく，ブラックカーボン，多環芳香族炭化水素類及び種々の大気汚染物質などの調査研究も実施されている．%For the determination of trace-level elements in metallic samples, several chemical procedures for the separation and pre-concentration from the matrix metals have been employed. However, troublesome problems are frequently encountered in the chemical separation procedure. Especially, the analytical values may contain errors due to contamination of the analyte from several experimental situations ; this phenomenon results in an increase and the variance in a blank value in analysis. For decreasing the blank value, it is necessary to evaluate the cause for contamination through the analytical procedure. The authors investigated the effects of contaminants attributed to the experimental tools, reagents and an environment on the blank value for the trace analysis of silicon in metallic samples in molybdosilicate blue spectrophotometry after silicon tetrafluoride separation. For analyzing trace silicon with better precision, the experimental instruments have to be cleaned and reagents containing the lowest concentration of silicon have to be selected and employed. Moreover, the analytical operations should be carried out in a short time and amounts of the reagents should be reduced as much as possible.