Herong Gui’s research while affiliated with Suzhou University and other places

The geochemical baseline is an essential reference for distinguishing natural and anthropogenic environmental impacts. It is of great significance for evaluating the changes in chemical substance (element) content and concentration before and after human development, as well as the evolution of environmental quality. Using background values such as the “Background Values of Chinese Soil Elements” and expanding the research scale can easily lead to “over protection” or “under protection” when guiding pollution control and governance. The article takes Wushan County, Chongqing City, in the Yangtze River Basin, as an example to collect 100 surface soils and construct a heavy metal environmental geochemical baseline. Analysis shows that the average values of As, Hg, Co, Cd, Pb, Cu, Ni, Zn, and Mn in the soil of the study area are 14.06, 0.09, 19.39, 0.99, 31.01, 37.08, 47.77, 121.10, and 960.20 mg/kg, respectively; The ground accumulation index indicates that heavy metals are mainly pollution-free and lightly polluted, but Cd, Hg, Cu, Ni, Zn, and Mn have a certain proportion of moderate pollution (43, 7, 2, 3, 2, and 1 point, respectively). Hg and Ni each have 1 medium to strong pollution level soil site, while Cd has 6 strong pollution sites, 4 strong to extremely strong pollution sites, and 5 extremely strong pollution sites. Based on the cumulative frequency curve method, the geochemical baseline values of Hg, As, Co, Cd, Pb, Cu, Ni, Zn, and Mn were obtained as 0.06, 12.69, 16.47, 0.22, 30.15, 24.61, 34.54, 104.40 mg/kg, and 628.32 mg/kg, respectively. The constructed soil heavy metal environmental geochemical baseline determines the evaluation criteria for small-scale spatial areas, which can scientifically and accurately identify the current soil pollution status in the region.

The migration, transformation, and accumulation of dissolved organic matter (DOM) in pore water of sediment cores play a pivotal role in lacustrine carbon cycling. In order to understand the dynamics of DOM in the sediments of large shallow eutrophic lakes, we examined the vertical profiles of DOM and the benthic fluxes of dissolved organic carbon (DOC) in sediment cores located in algae accumulated, dredged, and central areas of eutrophic Lake Taihu, China. Optical properties showed the significant influence of terrestrial inputs on the DOM components of pore water in the algae accumulated area but an abundant accumulation of autochthonous DOM in the central area. The benthic fluxes of DOC ranging from −458.2 to −139.4 mg·m−2·d−1 in the algae accumulated area displayed an opposite diffusion direction to the other two areas. The flux ranges of 9.5–31.2 mg·m−2·d−1 in the dredged area and 14.6–48.0 mg·m−2·d−1 in the central area were relatively smaller than those in the previously reported lake ecosystems with low trophic levels. Dredging engineering disturbed the pre-dredging distribution patterns of DOM in sediment cores. The deposition, accumulation, and transformation of massive algae scums in eutrophic lakes probably promoted the humification degree of sediments.

The scientific and reasonable evaluation of heavy metals pollution in estuarine sediments is crucial for characterizing the environmental quality of the lake, however, it is still unavailable due to the lack of local geochemical baseline concentrations (GBCs) and thus applying background values of soils. In this study, the statistical method of cumulative frequency was employed to obtain the GBCs, which were applied as reference standards for the pollution assessment of heavy metals and source apportionment in estuary sediments of northwestern Taihu Lake. The results showed that the GBCs of Cd, Cu and Zn were higher than soil background values in Jiangsu Province while Ni and Pb displayed a small gap between GBCs and background values. Cd, Ni and Zn presented a degree of moderate pollution or moderate to strong pollution according to geo-accumulation index (Igeo). The pollution load index (PLI) showed that 75% of samples ranged from non-pollution to moderate pollution level while 2.94% of samples exhibited a moderate to high pollution level. The possible sources of heavy metals in the estuary sediments were quantitatively identified by positive matrix factorization (PMF), including agricultural source (23%), the combined contribution of natural sources and traffic emissions (36%) and industrial source (41%).

Shale gas resource is heterogeneously distributed in Permian Gufeng Formation in the Xuancheng area, Anhui Province. This research aims to investigate the pore size distri- bution of the Permian Gufeng shales via 16 core samples analyses, combined with x-ray diffraction, low-pressure nitrogen gas adsorption (N2-GA), CO2 gas adsorption (CO2-GA) and scanning electron microscopy (SEM). N2-GA shows that the nanopores (diameter < 10 nm) are dominated and developed in the samples. The Brunauer– Emmett–Teller (BET) specific surface area (SSA) of the samples ranges from 6.7051 to 29.4384 m2/g, with a mean of 16.0931 m2/g. CO2-GA results illustrate that micropore is well developed, especially the pores with a diameter of 0.5–0.6 and 0.8 nm. The total organic carbon (TOC) content of the Gufeng shale ranges from 0.42% to 12.82% with an average content of 6.44%, which has both positive correlation with pore SSA and pore volume, while carbonate mineral content has a positive correlation with pore SSA and the volume of macropore and mesopore. Clay mineral content is a negative corre- lation with pore SSA and micropore volume. Therefore, the high-maturity Permian Gufeng shale could be more preferential high-quality gas shale reservoir for further exploration and development in the Xuancheng area, which has more than 4% TOC content, relatively higher carbonate mineral content and relatively lower clay mineral content.

Soil is the foundation of agricultural green development and human survival; the study of local environmental geochemical baselines can guide soil management and ensure the safe use of soil. In this study, a total of 100 shallow farmland soil samples were collected in each township of Yongqiao District, Suzhou City, Anhui Province, China. Herein, the contents of 10 heavy metal elements including As, Hg, Cd, Pb, Cr, Cu, Mn, Ni, Zn and Fe were determined. In addition, the geochemical baseline of heavy metals was calculated based on the relative cumulative frequency curve method, and the soil pollution status was evaluated. The results show that the average contents of As, Hg, Cd, Cu, Mn and Zn exceeded the soil background values of Anhui Province by 3.82%–64.74% (1.04–1.65 times), meanwhile, the average contents of Pb and Cr were lower than the soil background values of Anhui Province. The average contents of Cd, Cr, Cu, Mn and Ni exceeded the Chinese soil background values by 1.61%–64.74% (0.98–1.65 times). The geochemical baseline values of As, Hg, Cd, Pb, Cr, Cu, Mn, Ni, Zn and Fe were 9.585 mg/kg, 0.028 mg/kg, 0.112 mg/kg, 21.59 mg/kg, 53.66 mg/kg, 19.31 mg/kg, 543.8 mg/kg, 24.93 mg/kg, 50.57 mg/kg and 2.654%, respectively. The pollution assessment results also showed that most of the farmland soil samples in the study area were non-polluting or slightly polluted based on geochemical baselines. Hg and Cu in a few samples were moderately polluted, and Cd in only one sample was moderately intensely polluted. Combined with the distribution of pollution and field investigation, it is considered that Hg comes from atmospheric deposition and agricultural non-point source pollution of industrial pollution. Cu comes from animal husbandry and agricultural pollution. Meanwhile, Cd is related to natural sources, wood processing and agricultural fertiliser application. The study demonstrated that the calculation of soil geochemical background value should take full account of the differences between the various regions, combined with the current state, particularly the pre-consideration of the distribution of elements or pollutants. Then, reasonably select the evaluation standard value so that the evaluation results can truly reflect the state of soil pollution.

Spreading magnetic anomalies recorded the paleo-geomagnetic field variation that has great significance in the investigation of the extension process of ocean basins. Interpreting spreading magnetic anomalies under complex geological environments is challenging, especially for marginal sea basins. We proposed nested elliptical directional filters to separate the spreading magnetic anomalies of the South China Sea (SCS). The results show that the spreading magnetic anomalies separated by the nested elliptical directional filters depict the expansion process of the oceanic crust, and the interference magnetic anomalies are effectively suppressed. The separated spreading magnetic anomalies indicate that the expansion process of the SCS is affected by the interactions between the surrounding plates. The spreading magnetic anomalies of the SCS are warped, interrupted, and not strictly parallel. The pattern of the spreading magnetic anomalies reflects multiple ridge jumps during the expansion process and the post-spreading magmatic disturbances. The long-wavelength magnetic anomalies indicate lithospheric fractures and Curie surface variations in the SCS, which are affected by the post-spreading magmatic rejuvenation. The magnetic anomalies of the SCS resulted from the superposition of magnetic anomalies in the ocean crust and the uppermost mantle.

The shifting of livestock and poultry production systems from traditional small householder farms to semi-intensive and intensive farms has led to a gradual deterioration in the quality of shallow groundwater, which has attracted considerable attention from researchers. In this study, a combination of self-organizing map technology was used to identify the effects of livestock and poultry farms on shallow groundwater hydrochemistry. NO3–N content in the livestock and poultry farm water samples in summer and winter, as well as the NH4–N and NO2–N content in the water samples of livestock and poultry farm, respectively, in winter, were more vulnerable to external influences. Agricultural and industrial activities were important sources of Cl− and SO42− leaching in shallow groundwater in the study area. Silicate weathering is an important source of conventional ions in the shallow groundwater at these two sites. The water quality at livestock farms was mainly affected by farm activities and agricultural pollution in summer and winter, whereas that at poultry farms was mainly affected by industrial sources and natural sources.