[Quantifying the influence of different matrices on Pb accumulation in the soil from Nanjing and suspended matter from the lower of the Yangtze River with Pb isotopic technique].

Lead pollution and its geochemical behavior have an influence on ecological environment and human health. It is of significance to study the characteristics and mechanism of Pb accumulation and to quantify the contributions of different environmental matrices to Pb accumulation in soils and river suspended matter in the representative fluvial delta area, such as the lower of the Yangtze River. The results showed that lead was enriched in the urban topsoil in Nanjing and the suspended matter in the lower of the Yangtze River. The urban topsoil and the river suspended matter showed higher 206Pb/207Pb and lower 208Pb/206Pb relative to the natural matrices, and this was resulted from the influence of the anthropogenic lead. The relative contribution of separate Pb sources was assessed with the Pb geochemical model, 18%-56% (average 35%) Pb in Nanjing urban soil was derived from the anthropogenic matrices, and anthropogenic Pb contributed 22%-46% (average 32%) of total Pb in the Yangtze River suspended matter.

Reflectance spectroscopy study of Cd contamination in the sediments of the Changjiang River, China.

Sediments of the Changjiang River have been found in recent studies to be enriched in cadmium (Cd). The possibility and mechanisms for evaluating total Cd concentration and its binding form using reflectance spectroscopy within the visible-near-infrared (VNIR) region (400-2500 nm) have been investigated. Bottom sediments (69 samples) in the lower reaches of the river were collected for chemical analyses and spectral measurements. Total Cd concentration in the sediments was found to be exponentially related to the spectral proxies for organic matter(spectral reflectance at 400-530 nm), clay minerals (first derivative (FD) values at the shoulders related to absorption bands near 1400, 1900, and 2200 nm), and Fe oxides (FD values at 560-760 nm). The results indicated that the spectrally featureless Cd was mostly bound to these spectrally active materials, which made it possible for Cd concentration to be determined from reflectance spectra. This conclusion was also confirmed bythe results of chemically sequential extraction of Cd. This study has demonstrated the usage and theoretical basis of reflectance spectroscopy, which is a rapid and inexpensive analytical method, for evaluating contamination by heavy metals and their binding forms in sediments.