Mingguo Wang

Analyzing the hydrochemical characteristics and formation mechanism of metasilicic acid (H₂SiO₃) enrichment in the groundwater of Sanjiang Plain is conducive to guiding the rational development and utilization of mineral water resources in this region. Taking the groundwater in the typical black soil area of the northeastern Sanjiang Plain (from Qindeli Farm to Chuangye Farm) as an example, 104 groups of groundwater samples were collected to analyze enrichment and controlling factors of H₂SiO₃ by comprehensive methods such as hydrochemical analysis, rock geochemistry, water–rock interaction analysis, and ion ratio analysis. The results showed that the groundwater was generally in a reducing environment with low mineralization and weak acidity. The main cations were Ca²⁺ and Mg²⁺, and the main anion was HCO₃⁻. The hydrochemical types were mainly HCO₃–Ca and HCO₃–Ca·Mg, followed by HCO₃·Cl–Ca·Mg mixed type, and the H₂SiO₃ enrichment rate of groundwater reached 80.77%. The enrichment of H₂SiO₃ in the groundwater was related to the local geological structure and specific hydrogeochemical processes, and mainly controlled by the hydrolysis process of silicate rock minerals (such as albite, plagioclase, and olivine). The silicates and aluminosilicates contained in the basalt, diorite, and gneiss distributed in the area provided a rich material basis for the enrichment of H₂SiO₃. Its migration and distribution were simultaneously affected by leaching and cation exchange, while NO₃⁻ and SO₄²⁻ input from anthropogenic sources also participated in the rock weathering, specifically the enrichment process of H₂SiO₃ in the groundwater. From the perspective of mineralization conditions, Qinglongshan Farm and Qindeli Farm are potential areas for developing H₂SiO₃-rich mineral water. However, the main direction for the development and utilization of groundwater in this area should be to explore natural H₂SiO₃-rich groundwater with good comprehensive water quality.

Understanding groundwater quality and its controlling mechanisms is vital for the sustainable use of water resources in agriculturally intensive regions. This study evaluates the hydrochemical characteristics, controlling geochemical processes, and overall water quality of 226 groundwater samples collected from a typical agricultural reclamation area in the Sanjiang Plain, northeastern China. Major ion compositions indicate that groundwater is predominantly of the Ca–HCO₃ type, with bicarbonate, calcium, and magnesium as the dominant constituents. Spatial and statistical analyses reveal that rock weathering—particularly the dissolution of carbonates and silicates—is the primary natural process influencing groundwater chemistry, while cation exchange contributes moderately. Anthropogenic inputs, especially from fertilizers, livestock waste, and wastewater discharge, were found to elevate concentrations of NO₃⁻, Cl⁻, and SO₄²⁻ in localized zones. The entropy-weighted water quality index (EWQI) was applied to assess overall groundwater suitability. Results show that 89.8% of samples fall into “excellent” or “good” categories, though 6.6% of samples indicate poor to very poor water quality. This study identified the hydrochemical characteristics, sources of substances, and water quality of groundwater in the reclamation area, providing a basis for scientific prevention and control, rational utilization, and protection of groundwater resources.

Strontium (Sr) is one of the essential trace elements in the human body, which has important biological significance for human physiological function. In this paper, 41 groundwater samples collected from Shengli Farm in the eastern Sanjiang Plain were used to study the hydrochemical characteristics of Sr ²⁺ enrichment and its control factors by correlation analysis, principal component analysis, and Gibbs model, which is helpful to guide the rational development and utilization of local groundwater resources and ecological environment protection.The findings indicate that the groundwater exists in a reducing environment characterized by acidity and low salinity, with predominant cations being Ca ²⁺ and Mg ²⁺ , and predominant anions being HCO ₃ ⁻ . The predominant hydrochemical type is HCO ₃ ‐Ca·Mg, secondly by SO ₄ ·Cl‐Ca·Mg type. Principal component analysis identifies three primary elements influencing the evolution of groundwater quality. The weathering and dissolution of silicate and carbonate rocks are the primary forces influencing the chemical composition of water, secondly by the dissolution of evaporites. Groundwater with a Sr content over 0.40 mg/L constituted 7.32% of the total samples. The siliceous rocks and basalts present in this region supply the foundational material for Sr ²⁺ enrichment. Sr ²⁺ is correlated and coenriched with Ca ²⁺ and Mg ²⁺ , and the liberation of Sr ²⁺ from adjacent rock during cation exchange is one of the sources of Sr ²⁺ in groundwater. Regular agricultural and livestock practices are the primary contributors to the elevation of SO ₄ ^2- levels in adjacent groundwater, as well as the enhancement of Sr ²⁺ concentrations.

Groundwater is vital to local human life and agricultural irrigation, and the quality of the water is critical to human health. As a result, it is critical to investigate the hydrochemical evolution and water quality of groundwater in the Sanjiang Plain. There were 259 samples obtained. Furthermore, hydrogeochemical simulation was performed to highlight groundwater’s hydrochemical features, evolution process, and water quality. The analytical results show that the groundwater in the study area is somewhat alkaline with a mean TDS of 285.94 mgL⁻¹ and the primary contributing ions being Ca²⁺ and HCO₃⁻. The closer the concentration of TDS and NO₃⁻ is to the city, the higher the concentration, indicating that the chemical composition of the water body has been affected by certain human activities. The Piper diagram, Gibbs diagram, and correlation analysis results demonstrate that the chemical type of groundwater is mostly HCO₃-Ca and the hydrochemistry is primarily regulated by weathering and carbonate and silicate dissolution. According to the entropy-weighted water quality index, the groundwater quality in this location is pretty acceptable. This study could help strengthen groundwater quality monitoring based on local conditions, identify the source of nitrate, provide data support for the safe use of local water resources, and serve as a reference for global water chemical evolution and water quality evaluation in cold regions.

Groundwater resources are an essential component of global water resources. Long-term consumption of groundwater exceeding the standard levels for iron and manganese can lead to chronic diseases, posing a threat to human health. The Sanjiang Plain is the largest swamp wetland area in China and has high levels of iron and manganese in the groundwater, but the cause still needs to be clarified. Based on the results of water quality tests of 41 groundwater samples in the Eastern Sanjiang Plain, this paper analyzes the distribution characteristics and causes of iron and manganese from the perspectives of the original strata environment, redox conditions, pH conditions, and hydrochemical indicator factors in the research area, using statistical methods and GIS technology. The results show that high iron and manganese content in groundwater is prevalent in the Eastern Sanjiang Plain, and the exceedance rate of manganese is higher than that of iron (87.80% and 82.90%, respectively). The primary sources of iron and manganese in groundwater are iron and manganese minerals in the original strata environment. Influenced by factors such as acidic conditions, reducing environment, and rich organic matter, insoluble high-valent iron and manganese oxides are reduced to low-valent and soluble divalent iron and manganese. At the same time, groundwater’s high mineralization and evaporation concentration are conducive to increased iron and manganese content, while the influence of human activities is small.

With the rapid development of the economy, heavy metal soil pollution causes ecosystem deterioration and raises serious concerns. Topsoil samples (n = 205) were collected to investigate the pollution characteristics, risk levels, and pollution sources of heavy metals in the topsoil of eastern Tibet. Heavy metal contents, such as As, Hg, Pb, Cr, Mn, Mo, Ni, Cu, Zn, and Cd, in the soil were tested, and the potential sources were analyzed using correlational and principal component analysis. The results showed high content levels of Cd and Hg, which were 1.42 and 2.45 times higher than the background values of the Tibet Plateau at the beginning of this century, respectively. The enrichment factor (EF), geoaccumulation index (Igeo), and Nemero composite index (PN) showed that Cd and Hg were the main pollutants due to higher traffic flow and mining activities, but the pollution degree was generally not high and was relatively concentrated in the central and northern parts. The results of the principal component analysis showed that the heavy metals in the soil of eastern Tibet were mainly affected by natural factors and traffic factors, and mining activities and agricultural activities also played a certain role. Mn, Cr, Ni, As, Hg, and Cu were mainly affected by natural factors, while Pb, Zn, Cd, and Mo were affected by multiple factors, such as nature and traffic.

Rivers play an essential role in the global matter transport and hydrogeochemical cycle. Hydrogeochemical research is significant to developing and protecting water resources in the Qinghai-Tibet Plateau and its lower reaches. This study aimed to identify the hydrochemical characteristics and controlling factors of Daqu River and Gaqu River in Dingqing County, two tributaries of the upper Nujiang River. This study used spatial analysis, trilinear diagram analysis, and ion ratio analysis of hydrochemical indexes to investigate the hydrochemical characteristics and controlling factors. Results show that Ca²⁺ and Mg²⁺, and HCO₃⁻ and SO₄²⁻ are the main cations and anions of these two rivers. HCO₃·SO₄-Mg·Ca and HCO₃·SO₄-Ca·Mg are the primary hydrochemical types for the surface water of Daqu and Gaqu Rivers, respectively. The influence of atmospheric precipitation and anthropogenic activities is weak. The carbonated water–rock reaction is the main Ca²⁺, Mg²⁺, and HCO₃⁻ source, and hot springs act as the primary source of SO₄²⁻ and supplements Ca²⁺, Mg²⁺, and HCO₃⁻. Mg²⁺ from magnesite dissolution exists in the Daqu River basin. Weak reverse cation exchange occurs in both rivers. Daqu River receives more low-mineralized glacier meltwater along the flow, whereas Gaqu River receives more high-mineralized hot spring water.