Heavy metal refers to any metal element with a density above 4.5 g/cm 3 , such as cadmium (Cd), mercury (Hg), lead (Pb), copper (Cu), zinc (Zn), chrome (Cr), nickel (Ni), antimony (Sb), and arsenic (As) [1][2]. Elevated heavy metal content in soil has a huge impact on the growth of plants, including changes in the appearance of the plants (such as color, leaf shape, and size) and even death [3]. Heavy metal pollution in soil has become a worldwide environmental problem,

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To date, few systematic studies of the spatial distribution, formation mechanism, and health risks of high-fluoride (F−) shallow groundwater in humid and semi-humid areas of the Xikuangshan antimony mine, Hunan Province, China. In this study, during March and April 2022, a total of 39 shallow groundwater samples were collected and analyzed using factor analysis, principal component analysis, and health risk assessment. F− concentrations in the shallow groundwater were found to range from 0.08 to 15.00 mg/L (mean: 1.21 mg/L), with 25.64% of the samples having F− concentrations higher than in the Chinese national standard for drinking water (1.00 mg/L). Principal component analysis revealed that the main source of F− in the shallow groundwater samples is cation exchange, accounting for 73.40%, followed by the dissolution and precipitation of F-bearing minerals (15.10%), and human influence (11.50%). Among different age groups, children had the highest percentage of individuals (36.38%) with an F− intake above the health risk quotient safety limit, followed by adult males (23.12%), teenagers (22.21%), and infants (21.22%). The findings of this study will contribute to devising strategies for the provision of safe drinking water and management of the geological environment.

The origin and composition of dissolved organic matter (DOM) is crucial for fate of antimony (Sb) in aquatic systems. However, there are in which DOM compositional properties, that may better explain the biogeochemical process of Sb, have been absent. This study aimed to understand the fraction, spatial distribution, and spectral characteristics of DOM in high-Sb groundwater (commonly: >0.005 mg/L) from the Xikuangshan Mine in Lengshuijiang, Hunan, China, and explore the characteristics of DOM associated with the formation process of high-Sb groundwater. Inductively coupled mass spectrometry and excitation/emission matrix-parallel factor analysis were used to determine the Sb content, DOM composition, and fluorescence characteristics of 25 shallow groundwater samples collected in May 2021. The dissolved organic carbon (DOC) values in the shallow groundwater varied from 0.38±1.89 to 9.90±1.89 mg/L, with a mean of 2.49 mg/L. The DOM consisted of the following four components: C1, terrestrial humus; C2, microbial humus; C3, fulvic acid; and C4, tryptophan. DOM in high-Sb groundwater usually has a high humification index, low biological index, and low fluorescence intensity values. This result will help to understand the effect of DOM on the accumulation and migration of antimony in groundwater during biogeochemical cycling.

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