堆積物コア中鉛同位体比を用いた環境鉛汚染の歴史的な由来の識別

抄録

Pollutants are emitted into the atmosphere by human activity and are later deposited partly in the hydrosphere such as in ponds and lakes. Sediments in the hydrosphere retain the environmental pollutants over a long time. Using this property of sediments, many studies have revealed the historical changes in environmental pollution by sampling columnar sediment cores from the hydrosphere and estimating the deposition age of the core materials.
The sources of lead can be determined using lead isotope ratios, which vary depending on the source mine. The measurement of lead isotope ratios in sediment cores is therefore very useful for identification of the historical source of environmental lead pollution.
Lead in sediments is however derived from both anthropogenic sources and natural input and the lead isotope ratios of the sediment therefore consist of values averaged from the two sources. The present review describes a useful method of extracting anthropogenic lead from sediment and estimating its isotope ratios. This method can be used to estimate the isotope ratios of anthropogenic lead at the time of deposition in the environment of the sampling site. It also enables comparison of the isotope ratios of anthropogenic lead in one sediment with those in other sediments.