High levels of nitrates in groundwater pose a risk to human health. Hence, groundwater-human health risk assessment and sources analysis are essential. The article aims to assess risk level and identify sources of nitrate in shallow groundwater of the Liujiang basin by using a human health risk assessment (HHRA) model, Factor analysis (FA) and GIS spatial analysis. The results indicated that the most serious pollution was distributed in southern region of the basin; about 60% of the samples exceeded the recommended limit of nitrate as per the World Health Organization limit. Moreover, ingants' health risk were greater than those of adults and children, and about 56% of the groundwater samples will put the infants at risk of health. FA was used to identify various underlying natural and anthropogenic processes that created these distinct risk levels. The FA results can be categorized by two major factors: (1) Organic fertilizers and sewage discharge contamination in central region. (2) Blocking effect of granite and redox conditions in southern parts. This study demonstrates that the great variation of nitrate risk levels in the basin should be attributed to both natural and anthropogenic processes.

Active fault zones are critical pathways for the migration of deep fluids to the Earth’s surface, carrying gases such as He, Rn, and CO₂ that provide evidence for the physical and chemical dynamics of the Earth’s interior. This review examines the geochemical characteristics of fault zone gases and their implications for understanding fault activity and seismic events. Fault zones with high activity levels exhibit significant gas release, and variations in soil and hot spring gas concentrations can serve as indicators of seismic activity. Changes in gas concentrations and isotopic ratios, particularly before and after earthquakes, reflect the dynamic interplay between deep-sourced and shallow-sourced fluids. Seismic-induced stress alterations enhance gas release along fault zones, leading to observable anomalies that can aid in earthquake monitoring and prediction. The study underscores the importance of isotope tracing in deciphering fluid sources, migration pathways, and the evolution of fault zones, providing valuable information for assessing tectonic activity and mitigating seismic risks.

Concentrations of NO₃⁻(nitrate), NO₂⁻(nitrite), NH₄⁺(ammonia nitrogen), Mn, Fe, Ba, As, Se, Cd, Pb, Cr⁶⁺, estrone (E1), estradiol (E2), ethinylestradiol (EE2), estriol (E3), bisphenol A (BPA), nonylphenol (NP) and 4-tert-octylphenol (OP) had been estimated in water and sediments of Wenyu River. Using single factor, ecological risk assessment, geoaccumulation index, human health risk assessment and multivariate statistical analysis, we described the current situation of river contamination, human health risks of different age groups and possible sources of pollutants as well as their transformation characteristics. The results showed that main contaminants were NH₄⁺, NO₃⁻, NO₂⁻, EE2 and E3, E1 in water, while sediments have been slightly polluted by heavy metals, whose order of polluting degree is Zn>Cr⁶⁺>Cd>Cu. Residents in the study area are exposed to the risk, and EE2 made the greatest contribution to it. E1, As, and NO_3^- also affect negatively on the health of the residents, and NO_2^- only do harm to juveniles. Human activities and industrial production are main sources of contaminants, also they can transform into each other between water and sediments. Heavy metal ions can be easily precipitated by Ferric oxide or hydroxide, E2 and EE2 are also transformed into E3 in natural 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.