Groundwater arsenic and antimony mobility from an antimony mining area: Controls of sulfide oxidation, carbonate and silicate weathering, and secondary mineral precipitation.

Sulfide mineral oxidation has been recognized as the key driver of arsenic (As) and antimony (Sb) mobility in mining-impacted groundwater. However, the role of carbonate and silicate weathering and secondary mineral precipitation in this process remain unknown. A comprehensive geochemical study of groundwater was conducted in an Sb-mining area, Hunan, China, with samples collected from aquifers of the Xikuangshan Formation (Dx), the Shetianqiao Formation (Ds ), and the Lower Carboniferous Formation (Cy).

[Hydrochemical Characteristics and Genesis Mechanism of Groundwater in the Dry Period in the Zhangjiakou Area].

In order to better support the construction of the capital water conservation functional area and ecological environment support area， research on the chemical characteristics of groundwater and its formation mechanism in the dry period in the Zhangjiakou area can provide a great reference for the rational development and utilization of groundwater resources. A total of 41 groups of groundwater samples were collected， and the hydrochemical types， composition characteristics， and control factors of groundwater in the study area were analyzed by using the combined method of descriptive statistical analysis， Piper triplot， correlation analysis， Gibbs plot， and ion ratio. The results showed that the groundwater in the study area was weakly alkaline， with the total hardness and （TDS） ranging from 105.

[Evaluation and Source Analysis of Soil Heavy Metal Pollution in a Planting Area in Wanquan District, Zhangjiakou City].

Taking the soil of a vegetable planting area in Wanquan District of Zhangjiakou City as the research object, 132 surface and 80 deep soil samples were collected to test and analyze the contents of eight heavy metals such as As, Cd, Cr, Hg, Cu, Ni, Pb, and Zn and the occurrence forms of Cr and Ni. By applying geostatistical analysis and the PMF receptor model and combining three heavy metal pollution evaluation methods, the spatial distribution characteristics of soil heavy metals in the study area, the degree of heavy metal pollution, and the distribution of Cr and Ni fugitive forms in the vertical layer were clarified, and the sources and contribution rates of soil heavy metal pollution were analyzed. The results showed that the average contents of Cd and Pb in surface soils were higher than the background values of soils in Hebei Province, and the spatial distribution characteristics of Cr, Ni, Cu, Cd, Pb, and Zn in surface soils were similar.

[Characteristics and Causes of Ge Enrichment in Vegetable Growing Areas of Beixintun Town, Zhangjiakou City].

The vegetable planting base in the Beixintun area of Zhangjiakou City was selected as the study area, divided into the focus area and regional range as well as the upstream area. A total of 132 surface soil samples, 16 vertical soil profiles, 3 groups of surface profiles, and 4 samples each of colored pepper fruit, purple kale fruit, and corn fruit were collected. From the soil, rock, and crop sample Sc, Cr, Mo, Cd, V, Zn, Sr, Pb, Co Ni, Cu, Ge, and REE on the basis of the referenced germanium (Ge) enrichment standards and enrichment factor levels, it was found that the regional Ge enrichment rate was not high (19.

Effects of calcium ion and pH on the adsorption/regeneration process by activated carbon permeable reactive barriers.

Activated carbon (AC) is widely used in groundwater remediation, more specifically, for the activated carbon permeable barriers (AC-PRBs). However, the long-term use of AC-PRBs is limited by the AC's adsorption capacity. In this work, a Fenton-combined persulfate system (Fe/HO/SO ) was used to treat activated carbon that was saturated with organic compounds, such as trichloroethylene (TCE), to promote the oxidation of the adsorbed contaminants and the regeneration of AC.