[Hydrochemical Characteristics of Surface Water and Groundwater in Shiyan Urban Area and Sources of Nitrate].

Nitrate pollution in water bodies is a worldwide environmental problem, and identifying the sources of nitrate is of great significance to guarantee the sustainable use of water resources. A variety of water chemistry indicators and nitrate nitrogen and oxygen isotopes （N-NO and O-NO） were used to analyze the water chemistry characteristics of water bodies in Shiyan to identify the sources of nitrate in the water bodies and to calculate the contribution rate of nitrate from different pollution sources of the water bodies using the SIMMR model. The results showed that the hydrochemical types of surface water and groundwater in the study area were dominated by the HCO-Ca·Mg type, and the formation of nitrate in the water body was mainly affected by nitrification, with non-obvious denitrification.

Integrated impacts of mariculture on nitrogen cycling processes in the coastal groundwater of Beihai, southern China.

Groundwater nitrogen (N) contamination in coastal zones is becoming an increasingly serious global issue. Mariculture, as a major anthropogenic activity, has profound impacts on coastal groundwater and constitutes an important source of coastal N contamination. However, a comprehensive understanding of the impact of mariculture on N cycling (especially N removal) is still lacking.

Seasonal Dynamics of Methane Fluxes from Groundwater to Lakes:Hydrological and Biogeochemical Controls.

Methane (CH) inputs to lakes through lacustrine groundwater discharge (LGD-derived CH) represent a potentially important but often overlooked source of lake methane emissions. Although great efforts have been made to quantify LGD-derived CH fluxes and their spatial variablity, the underlying mechanisms controlling seasonal LGD-derived CH fluxes and their influence on lake CH emissions remain poorly understood, particularly in humid inland areas. To address this gap, we applied the Rn mass balance model, as well as hydrological, isotopic and microbial methods to assess seasonal LGD-derived CH fluxes and their influence on the seasonal variability of lake methane emissions in a typical oxbow lake, central Yangtze River.

Experimental test and mechanism analysis of soil crust erosion resistance of rammed earth Great Wall in rainy season.

Rammed earth is a kind of cleaning material, widely used in all kinds of buildings in the world. The Great Wall of ancient China is a typical world cultural site built from rammed earth. The rammed earth Great Wall of Shanhaiguan is close to Bohai Bay, which has suffered from long-term erosion by rain, causing a series of problems such as soil loss, collapse and gully flushing.

Development of three chalcopyrites and one copper metal as potential reference materials for copper isotopic analysis by LA-MC-ICP-MS.

Rationale: Laser ablation multicollector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) has become a powerful technique for in situ Cu isotopic analysis in natural geological samples. Cu isotopic compositions in natural chalcopyrites have been used to reveal aspects of the mineralization processes directly. However, internationally or commercially available matrix-matched chalcopyrite reference materials for mass fractionation correction or quality control purposes are still lacking for in situ Cu isotopic analysis using LA-MC-ICP-MS.

Coupled effects of sedimentary iron oxides and organic matter on geogenic phosphorus mobilization in alluvial-lacustrine aquifers.

The organic matter (OM) biodegradation and reductive dissolution of iron oxides have been acknowledged as key factors in the release of geogenic phosphorus (P) to groundwater. However, the coupled effects of natural OM with iron oxides on the mobilization of geogenic P remain unclear. Groundwater with high and low P concentrations has been observed in two boreholes in the alluvial-lacustrine aquifer system of the Central Yangtze River Basin.

Degradation of Typical Reverse Sand-Mudstone Interbedded Bank Slope Based on Multi-Source Field Experiments.

The bank slopes in the Three Gorges Reservoir area (TGRA) have experienced obvious deterioration under the action of the periodic fluctuations in the reservoir water level. Generally, laboratory tests have been used to reveal the evolution trend of the slope banks. However, this method has a certain degree of cross-scale problem, especially for the mechanical state in a complex environment.

Distribution, Risk Assessment and Source of Heavy Metals in Mangrove Wetland Sediments of Dongzhai Harbor, South China.

Heavy metals are common environmental contaminants that are toxic, non-biodegradable, and bioaccumulative. They can bioaccumulate through the food chain and present a risk to both public health and ecology. Therefore, this study takes the mangrove wetland of Dongzhai Harbor as an example.

Ecological Health Risk Assessment and Source Identification of Heavy Metals in Surface Soil Based on a High Geochemical Background: A Case Study in Southwest China.

A total of 28,095 surface soil samples were collected in areas with high natural background levels; the potential ecological risk is generally low, and the high-risk area is small and mainly affected by lead−zinc mines. The contribution to the potential ecological risk factor (RI) is as follows: Hg > Cd > As > Pb > Cu > Ni > Cr > Zn, with noncarcinogenic chronic risks of Cr > As > Cd > Pb > Ni > Cu > Hg > Zn; furthermore, dermal contact is the main pathway of exposure causing health risks. The total carcinogenic risks caused by heavy metals were as follows: Cr > Cd > As > Pb; and the risks posed by Cr, Cd, and As were higher than the threshold value (1.