[Pollution of Heavy Metals in Topsoil of Remote Mountainous Areas in Western Yunnan-Guizhou Plateau].

Heavy metals from anthropogenic emissions have had a negative impact on the ecological environment in remote regions. A total of 69 topsoil samples were collected from 13 remote mountainous areas in the western Yunnan-Guizhou Plateau at altitudes of 2 563-4 037 m, and the concentrations of ten heavy metals in the samples were determined. Enrichment characteristics and pollution sources of heavy metals in topsoil were discussed by referencing the enrichment factor （EF）, positive matrix factorization （PMF）, and Pb isotopes.

[Spatial-temporal Variations and Pollution Assessment of Heavy Metals in Sediments of Qionghai Lake in Xichang City].

Based on the analysis of the total concentrations of 10 metals in the sediment core and total concentrations and chemical fractions of seven metals in the surface sediments of Qionghai Lake in Xichang City, Sichuan Province, the spatial-temporal characteristics of metal accumulation and pollution over the past century and the potential ecological risk of metals in surface sediments were studied. Before the 1970s, metal concentrations in the sediment core were stable. The total concentrations of Al, Fe, K, and Cr in the sediment core exhibited visible peaks in the 1970s, which were related to the enhanced input of fine-grained topsoil caused by increasing precipitation, lake reclamation, and deforestation.

[Historical Trends of Atmospheric Trace Metal Pollution in Northern Guizhou Province as Reconstructed from Alpine Lake Sediments].

Atmospheric trace metal pollution is a striking environmental problem globally. Because of the limitations in monitoring data, our knowledge of the historical processes and sources of atmospheric trace metal pollution in China and its influence on remote terrestrial environmental quality is limited. The historical variations in atmospheric trace metal (Cd, Cr, Cu, Hg, Ni, Pb, and Zn) pollution during the past 400 years in the Fanjing Mountain area, northern Guizhou Province were studied by analyzing the metal concentrations and Pb isotopes in lake sediments.

[Contamination and Potential Ecological Risk Assessment of Heavy Metals in the Sediments of Yilong Lake, Southwest China].

The concentrations of Al, Ti, As, Cd, Cr, Cu, Ni, Pb, Zn, and Hg and chemical speciation of Cd, Cr, Cu, Ni, Pb, and Zn in four short cores sampled from the Yilong Lake, Yunnan Province were analyzed. The vertical and spatial features in the pollution levels and potential ecological risks of heavy metals in the sediments were studied. Except for the wide concentration ranges of Cd, the metals in the sediments showed narrow variations in their concentrations with coefficients of variation less than 0.

[Spatio-temporal Variations, Contamination and Potential Ecological Risk of Heavy Metals in the Sediments of Chenghai Lake].

Heavy metals pollution in the sediments is one of the main factors impacting the water quality and ecosystem health. In this study, concentrations of ten metals in nine sediment cores from the Chenghai Lake were determined. Chronology of a typical core (CH2012) was constructed by the Pb and Cs dating method.

[Effects of anthropogenic organic matter inputs on stable carbon and nitrogen isotopes in organisms from microbial food chain in Taihu Lake].

Stable isotope analyses of carbon and nitrogen were used to evaluate autochthonous versus allochthonous contribution to the main microbial food loop components in the four sampling sites based on different trophic status in Taihu Lake. On average, the delta13 C and delta15 N values of organic matter (OM) sources (bacteria, cladocera, particulate and sedimentary organic matter) and the delta13 C of dissolved inorganic carbon (DIC), which are the main components in microbial food chain, showed the lowest values at estuary location compared with the other three sites, reflecting a strong influence by terrestrially derived nutrients and organic matter. The mean delta13 C value of dissolved organic matter (DOM) that we measured was close to the estimated terrestrial delta13 C - 26 per thousandd, suggesting an allochthonous-derived organic C pool.