[Multiproxy Comprehensive Analysis for Source Apportionment and Pollution of Heavy Metals in Urban Drinking-water Source Soils from the Lanzhou Reach of the Yellow River].

To elucidate the pollution characteristics and sources of heavy metals in the soil of drinking water sources in urban areas of the Yellow River Basin, the soil in the water source areas for urban drinking water in the Lanzhou section of the Yellow River was selected as the research object. The content characteristics of heavy metals, including As, Cd, Cr, Hg, and Pb, were analyzed. The pollution degree of heavy metals was quantified systematically using the geo-accumulation index, contamination factor, pollution load index, and improved Nemerow comprehensive pollution index.

[Identification Priority Source of Heavy Metals in Urban Soils Based on Source-specific Ecological Risk Analysis in a Typical Tourist City].

To understand the pollution status, distribution characteristics, and pollution sources of soil heavy metals in tourist cities in northwest China, the soil content of heavy metals As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn in the main areas of Dunhuang City was collected and analyzed. The soil heavy metal pollution level was quantitatively evaluated by the methods of the geo-accumulation index and improved Nemerow pollution index, and the sources of heavy metal pollution were quantitatively analyzed using cluster analysis and the positive matrix factorization （PMF） model. The contribution rate of each pollution source to ecological risk was determined by combining the PMF model and comprehensive ecological risk index.