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Abstract A high geological background can increase the ecological and health risks associated with crop production; therefore, it is essential to assess the heavy metals and their impact. In this study, ecological and health risk impacts of heavy metal contamination, in combination with positive matrix factorization was assessed for an area with high geological background with wheat–maize cropping system, to provide a quantitative understanding of the effects of heavy metals, enabling its prevention and control. This study revealed that the comprehensive ecological risk (RI wheat–maize ) is 56.21 (low), with industries being the biggest contributors (34.22%). Comprehensive health risk (non-carcinogenic) assessment showed that industrial (40.98–49.30%) and natural (23.96–37.64%) factors were the primary (particularly of Cd and Zn) and secondary (particularly of Cr and Ni) contributors, respectively in eastern China. Comprehensive health risk (HI wheat–maize ) for children and adults were 0.74 and 0.42, respectively, indicating that non-carcinogenic risks were at an acceptable level. Soil ingestion was the primary pathway for health risks (62.23–73.00%), especially for children. Based on soil heavy metal sources and crop systems, source-ecological risk assessment and source-health risk assessment were used to provided valuable insights on making strategies to protect human health in high geological background areas.

Qilian Mountain is the only permafrost area in China where natural gas hydrates have been obtained through scientific drilling. Many studies have been performed on natural gas hydrates in permafrost regions from the perspectives of sedimentology and petroleum geochemistry, especially on reservoir forming conditions and exploration methods. However, there are still more divergences in its evolutionary process, time, and accumulation mechanism. In this study, a total of 500 core samples were collected in the gas hydrate drilling wells DK-8, DK13-11, and DK12-13 in the Qilian Mountain permafrost. Gas components, carbon isotopes of methane, total organic carbon (TOC), chloroform bitumen “A,” concentrations of kerogen element, and vitrinite reflectance (Ro) are analyzed. The results show that the hydrocarbon source rocks in the Middle Jurassic Muli formation and the Upper Triassic Galedesi formation are good source rocks, with good total organic carbon content and chloroform bitumen “A.” The rocks of Muli formation are at the mature stage of organic matters, and the organic matter types are mainly Ⅱ1 and Ⅱ2 and the peak of generating crude oil with immense petroleum-associated gas. Also, the rocks of the Galedesi formation are in a highly mature stage, producing more gas and offering efficient gas for the natural gas hydrate, and the organic matter types are mainly Ⅲ and Ⅱ1. Laboratory experiments and numerical analysis indicate that the formation of natural gas hydrates in the Qilian Mountain has experienced three phases: gas migration and aggregation in the Late Jurassic to Early Cretaceous, overall uplift in the Middle and Late Miocene to Pliocene, and free gas to natural gas hydrate deposits in the Quaternary. The experimental results show that gas sources, permafrost thickness, and structural conditions played a key role in controlling the occurrence and distribution of gas hydrates.

Chishui River is an important ecological security barrier area in the upper reaches of the Yangtze River in China. Therefore, it is of great significance to conduct research on soil and water ecological risks in the Chishui River basin. In this paper, the risk of heavy metals pollution and its control factors was evaluated systematically by using surface water and soil samples from 16 tributaries in the Yunnan section of the Chishui River basin. The method of soil environmental capacity and ecological risk index were studied. The results showed that the average concentration of heavy metals in the surface water of the main stream was in the order of Fe > Mn > Zn > Cu > Pb > Cd > Hg. Except for Hg, all the concentrations of heavy metals were far lower than the Class I water limits in the Environmental Quality Standards for Surface Water (GB3838-2002) issued by the Ministry of Ecology and Environment, PRC. The average concentration of Hg concentration was 0.056 μg·L−1, which was slightly higher than the limit value of Class II. Heavy metals in the surface water were distributed in a point-like manner in the main stream of the Chishui River, which was mainly affected by mining drainage, township sewage, and human production activities. Meanwhile, the environmental capacity study showed that the heavy metals in soil were in the order of Zn > Pb > Cr > Ni > As > Hg > Cu > Cd, and the environmental capacity were significant differences among different soils: purple soil > limestone soil > loess > yellow-brown soil. Soil Cd tended to migrate out of the soil under the control of the occurrence form, vegetation coverage, and human production activities, while Cr, Cu, and Ni tended to accumulate in the soil. The average comprehensive ecological risk index (RI) of heavy metals in all tributaries ranged from 44.86 to 154.15, mainly distributed in medium and low ecological risk. Therefore, it is recommended to dynamically monitor and control these pollution points in the Chishui River basin to prevent the risk of heavy metals from escalating.

Triassic granitoids are abundant on the northwestern margin of the Tibetan Plateau. The Dahongliutan pluton, located in the eastern Western Kunlun orogen, formed in the Late Triassic.Previous field studies have identified potential mixing of crustal and mantle magmas. In this study, we used zircon U–Pb ages and major and trace elemental analyses to investigate the tectonic evolution of the pluton, and to determine whether any exchange of mantle-derived material occurred between the pluton and the source area. We found that the pluton has relatively high SiO2 contents, and the aluminum saturation index is consistent with peraluminous high-K calc-alkaline granite. The pluton is enriched in light rare earth elements; both light and heavy rare earth elements are highly fractionated. The magma that formed the pluton was predominantly derived from the crust; however, a small amount of upper mantle material was involved in the early stages of magma formation. The pluton underwent composite emplacement as a result of tectonic extension and magmatic emplacement, which may have occurred in the late Triassic post-collisional orogenic stage. Late Triassic magmatism provided heat and ore-forming material for Pb–Zn, Cu, Fe, and rare metal mineralization, which is of considerable importance for geological prospecting.

This study collected 1135 topsoil samples of cultivated land in Laiyang County, eastern China, to analyze the distribution, pollution and health risks of heavy metals (As, Cd, Cu, Cr, Hg, Ni, Pb and Zn). The results show that: (1) the levels of eight heavy metals at some sites were higher than the risk screening values in China, and there was heavy metal pollution. (2) An improved geoaccumulation index was used to evaluate soil pollution. The average value of Igeo before and after improvement was 0.32 (Iml, no pollution to medium pollution) and −0.04 (Iol, no pollution), respectively. (3) Hg and Cd were identified as the main contributors to ecological risk in this study, with a cumulative ecological risk contribution percentage > 65%. The results of the potential ecological risk index (PERI) show that 9.3% of the sampling sites were considered to have moderate ecological risk. (4) As, Pb, Ni and Cu made a contribution of >95% in terms of non-carcinogenic risk to adults and children through different exposure routes, and different soil intake routes posed no non-carcinogenic risk to adults; there was a sampling site with HQChildren > 1, which was consistent with the non-carcinogenic risk site, indicating that children in this location and surrounding areas are more likely to face dual health risks. Therefore, it is necessary to promote the risk management of heavy metals in the study area in order to safely use soil resources.

Heavy metal pollution of soil in agricultural areas is the most prominent environmental pollution problem in China, seriously affecting human health and food security. It has become one of the environmental problems to which all sectors of society attach great importance. Soil heavy metals in the weathering area of hazardous geological bodies in southwest China have naturally high background attributes. Therefore, ecological risk assessment and analysis of potential sources of soil heavy metals in southwest China is of great significance for soil health management, soil heavy metal pollution control and territorial spatial planning. In this study, we collected 787 soil samples (0–20 cm) in Xuanwei County in China and analyzed the concentrations of As, Cd, Cr, Cu, Hg, Ni, Pb and Zn in soils. Igeo, RI, HI and CR were used to calculate the pollution levels, ecological risks and human health risks. Additionally, the PMF model and one-way ANOVA were used to identify the potential sources and discuss the factors affecting the enrichment of heavy metals. The results showed that the mean contents of the surface soils were 1.190 (Cd), 139.4 (Cr), 96.74 (Cu), 0.081 (Hg), 56.97 (Ni), 46.66 (Pb) and 130.1 (Zn) mg/kg. All heavy metals exceeded the background values of the A layer soil in Yunnan Province. The Igeo showed that Cd was the most hazardous element in the study area, followed by Cu, Cr, As, Ni and Pb. The RI showed that low ecological risks, moderate ecological risks, considerable ecological risks and strong ecological risks accounted for 3.81%, 55.27%, 37.74% and 3.18%, respectively, of the total samples, and Cd was the main dominant element. The HI values of the As element in children were greater than 1, indicating a non-carcinogenic risk, and other elements’ risks were acceptable. The CR values of Cr and Ni were higher than their limits (1 × 10−4), and both had carcinogenic risks in children and adults, as did As in children. According to the PMF model, four heavy metals sources were identified: geological sources (32%), sources from mining activities (19.38%), atmospheric deposition sources (17.57%) and agricultural sources (31.05%). Thereinto, As and Pb were mainly derived from agricultural sources, Cd and Cr were mainly associated with geological sources, Cu was largely from mining activity sources, Hg was mainly from atmospheric deposition sources and Ni and Zn were mainly from geological sources, mining activities and agricultural activities. The parent material has a significant influence on the enrichment of heavy metals in the soil, and the heavy metals are significantly enriched in the carbonate parent material and quaternary parent material. Topography also plays a role in heavy metal accumulation; Cd, Cr, Cu, Ni and Zn gradually decreased with the increase in altitude, and As and Pb increased with the increase in altitude. Mn-oxide played a crucial part in the enrichment of Cu and Zn, while SOC, K2O and pH had little influence on the accumulation of heavy metals.

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 (1.0 × 10−4); people face a higher threat to heavy metals in soils in Zhenxiong, Ludian, Huize, Weixin, and Zhaoyang. The evaluation result of the EPA PMF model shows that the soil heavy metals are mainly composed of five sources, of which basalt, Permian, and Triassic carbonate rock parent material constitute the natural background source, while the mining activities of lead–zinc mines and the emissions of coal burning by residents constitute the anthropogenic source. The contribution was ranked in order of lead–zinc mining (26.7%) > Triassic carbonate (23.7%) > basalt (20.9%) > coal burning and automobile emissions (16.1%) > Permian carbonate (12.6%).

Various human production activities have caused tremendous damage to the soil ecological environment of cultivated land. Regional ecological risk assessments and the safe use of cultivated land have received widespread attention. The ecological risk assessment of heavy metals based on soil geochemical zoning has not been reported in the past. Using 14,389 topsoil samples, considering comprehensive geological background information, Yishui County in northern China was divided into three soil geochemical areas and 14 soil geochemical sub-regions by means of principal component factor superposition. The results of environmental quality and risk assessments of eight heavy metals based on soil geochemical zoning show that the single pollution index was greater than 1.0 and the Nemerow pollution index was greater than 0.7 for Ni in a sub-region, indicating that Ni pollution had reached the early warning limit, which demonstrates that Ni has a certain enrichment trend. Meanwhile, the geoaccumulation index of Ni and Cr was greater than zero in some sub-regions, indicating a slight pollution level. In addition, the potential ecological risk factor of the measured heavy metals was greater than 40 in 9 sub-regions, indicating a moderate ecological hazard, and the risk index was greater than 150 in a sub-region, revealing moderate ecological intensity, in which Hg and Cd were leading contributors to potential ecological hazards with a contribution rate between 58% and 76%. This method is suitable for the evaluation of soil environmental quality and safety for medium and large scales, and can provide a scientific basis for further zoning and grading prevention and control of soil pollution in cultivated land.

Gold content of a low-grade gold ore in Guangxi is 1.29 g/t, the gangue minerals are mainly quartz, and the content of non-ferrous metals such as copper, lead, zinc and other harmful elements arsenic is extremely low. The cyanide gold leaching test was carried out on the ore, and the effects of grinding fineness, pH value of solution, cyanide dosage, stirring speed and leaching time on the gold leaching effect were investigated respectively; The leaching aids with better leaching effect were mixed in the same proportion, and three new leaching aids A, B and C were obtained; for a low-grade gold ore in Guangxi, a cyanide leaching aid leaching test was carried out. The results show that the sample fineness of -0.074 mm accounts for 93.27%, the pH value of the solution is 10.5, the dosage of potassium cyanide is 4 kg/t, the stirring speed is 1500 r/min, and the leaching time is 24 h, the gold leaching rate is 24 h. 92.58%; the amount of potassium cyanide was reduced to 3 kg/t, and the other conditions remained unchanged, after adding the new leaching aid A for 18 h, the leaching rate of gold could reach more than 93%. The addition of the new leaching aid effectively improves the leaching rate of gold, reduces the loss of cyanide by 25%, and shortens the leaching time by more than 6 h.

The high-precision calibration results of the petroleum underground layer are of great significance for oil production efficiency. This study uses the gravity magnetic model to retrieve the bedrock depth. The results of the basement structure and sedimentary rock distribution through the gravity and magnetic geology in the petroleum underground prospect of the Tongbai basin were also obtained. On this basis, the geological data, logging data, seismic data, and the Vertical Seismic Profile (VSP) data has been comprehensively used, as the layered calibration method was used to calibrate the petroleum underground layer. Considering the seismic datum and the core elevation in the area, the rock formation is divided by various logging curves. The average time difference and density of the divided rock layers are interpolated at equal depth intervals to obtain velocity sequences and density sequences at equal time intervals and finally realize time-depth conversion. When the drilling geological horizon is unified, the synthetic record of the seismic reflection layer is compared with the geological horizon to realize the horizon calibration of the seismic reflection layer. When the local stratification is not uniform, the seismic reflection layer is calibrated by tracking the seismic reflection layer, high-precision velocity analysis, and various synthetic records to verify the reliability of the geological horizon. The results show that the proposed method can accurately survey the geological conditions of the Tongbai basin. It detected 14 basement faults, and that the NW-trending and NE-trending faults controlled the basin, while the North-South faults controlled the later evolution of the basin. The method can be used for the horizon calibration of inclined wells, which is suitable not only for anisotropic media but also for formations with a less lateral variation of local formation lithology. Moreover, its usage is flexible, and it can be corrected by multiple speed data. [ABSTRACT FROM AUTHOR]