[Evaluation and Source Analysis of Soil Heavy Metal Pollution in a Planting Area in Wanquan District, Zhangjiakou City].

Taking the soil of a vegetable planting area in Wanquan District of Zhangjiakou City as the research object, 132 surface and 80 deep soil samples were collected to test and analyze the contents of eight heavy metals such as As, Cd, Cr, Hg, Cu, Ni, Pb, and Zn and the occurrence forms of Cr and Ni. By applying geostatistical analysis and the PMF receptor model and combining three heavy metal pollution evaluation methods, the spatial distribution characteristics of soil heavy metals in the study area, the degree of heavy metal pollution, and the distribution of Cr and Ni fugitive forms in the vertical layer were clarified, and the sources and contribution rates of soil heavy metal pollution were analyzed. The results showed that the average contents of Cd and Pb in surface soils were higher than the background values of soils in Hebei Province, and the spatial distribution characteristics of Cr, Ni, Cu, Cd, Pb, and Zn in surface soils were similar. The ground accumulation index method showed that the study area was mainly free of pollution, with a small number of lightly polluted sites, and most of them were polluted with Cd. The enrichment factor method showed that the study area was mainly free-weakly polluted, with medium pollution of all elements; the significantly polluted elements in the background area were As, Pb, and Hg, and the significantly polluted element in the key area was Cd. The potential ecological risk index method showed that the study area was mainly lightly polluted, with local distribution. The potential ecological risk index method showed that the study area was mainly lightly polluted, with a local distribution of "medium" and "strong" risk points, with "very strong" risk points for Hg in the background area and "very strong" risk points for Cd in the focus area. These three evaluation results indicated that the background area was dominated by Cd and Hg pollution, whereas the focus area was dominated by Cd pollution. The study on the fugitive morphology of vertical soil showed that Cr was dominated by the residue state (F4) and supplemented by the oxidizable state (F3), and the vertical direction was dominated by the surface aggregation type and supplemented by the weak migration type. Ni was dominated by the residue state (F4) and supplemented by the reducible state (F2), and the vertical direction was dominated by the strong migration type and supplemented by the weak migration type. The sources of heavy metals in the surface soil were divided into three categories; Cr, Cu, and Ni were mainly from natural geological background sources. The contributions of Cr, Cu, and Ni were 66.9%, 66.9%, and 76.1%, respectively. As, Cd, Pb, and Zn were mainly from anthropogenic sources, with contributions of 77.38%, 59.2%, 83.5%, and 59.5%, respectively. Hg was mainly from dry and wet atmospheric deposition, with a contribution of 87.8%.

[Characteristics and Causes of Ge Enrichment in Vegetable Growing Areas of Beixintun Town, Zhangjiakou City].

The vegetable planting base in the Beixintun area of Zhangjiakou City was selected as the study area, divided into the focus area and regional range as well as the upstream area. A total of 132 surface soil samples, 16 vertical soil profiles, 3 groups of surface profiles, and 4 samples each of colored pepper fruit, purple kale fruit, and corn fruit were collected. From the soil, rock, and crop sample Sc, Cr, Mo, Cd, V, Zn, Sr, Pb, Co Ni, Cu, Ge, and REE on the basis of the referenced germanium (Ge) enrichment standards and enrichment factor levels, it was found that the regional Ge enrichment rate was not high (19.7%), whereas the key area had a high Ge enrichment rate (52%). The spatial distribution of Ge and rare earth elements in the soils of the regional scope and the focal area showed a more obvious consistency, and further comparison of the correlation characteristics of Ge and rare earth elements in soil and crops showed that the ranking of rare earth content was purple kale>colored pepper>maize, whereas the ranking of the Ge element uptake intensity was maize (weak uptake)>purple kale (very weak uptake)>colored pepper (very weak uptake), and there was no obvious synergy between the uptake of Ge and rare earth elements by crops. The PMF and RDA analysis of 28 elements and indicators of soil in the study area showed that the source of regional Ge was dominated by natural geological background factors (66.3%), supplemented by anthropogenic activity-influenced factors (27%) and river deposition factors (6.7%). The source of Ge in the focal area was dominated by natural geological background factors (33.8%) and anthropogenic activity-influenced factors (27.2%), with river sedimentation factors (18.5%) and atmospheric dry and wet deposition factors Ge (20.5%) being supplemented. Soil Ge was positively correlated with rare earth elements and trace elements such as Cd, Zn, Mn, Ni, V, Co, and Cr and negatively correlated with the main elements CNa2[KG-*2/5]O, SiO2, and K2[KG-*2/5]O and pH. Finally, by combining the analysis of soil lateral profiles with vertical profiles, it was found that the Ge migrating from the source area to the area was primarily in the main river pathway, supplemented by the secondary river and flood flow pathways.

Spatiotemporal evolution of nutrients and the influencing factors in Laizhou Bay over the past 40 years.

The nutrient status in Laizhou Bay has changed in composition and structure as a result of anthropogenic activities and climate change, which has led to several environmental problems (e.g., eutrophication, organic pollution and red tides). To better understand the spatiotemporal variations in dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP), and eutrophication in the Laizhou Bay, we collected historical research data and conducted four cruises in 2021. The highest surface DIN was found to occur in autumn and predominantly concentrated in the southwestern bay. The highest surface DIP content was found in winter and distributed in the northwestern bay. Surface organic pollution showed estuaries as the most polluted areas. In the past 40-60 years, the DIN, DIP, and eutrophication have shown an inverted U-shaped trend, and the bay has changed from N limitation to P limitation. Economic development, phytoplankton absorption, and bottom mineral release are factors influencing the content and distribution of nutrient in the bay.

Processing of dissolved organic matter from surface waters to sediment pore waters in a temperate coastal wetland.

Coastal wetlands are active transitional ecotones between land and ocean, and are considered as hot spots of organic matter processing within the global carbon cycle, which dissolved organic matter (DOM) plays a critical role. In this study, combined use of ultrahigh-resolution mass spectrometry (FT-ICR MS) and complementary optical techniques was conducted to assess the detailed molecular composition of DOM in the temperate Liaohe coastal wetland (LCW), NE China in respect to the differences in DOM composition from surface water to sediment pore water. Significant positive correlations between salinity and dissolved organic carbon (DOC) concentrations were observed in both surface waters and pore waters. Pore water DOM is generally characterized by lower protein-like fluorescence and biological index, but higher humification and humic-like fluorescent components than those in surface water DOM. Corresponding to the optical properties, FT-ICR MS measurements show that pore water DOM has higher proportions of heteroatoms, aromaticity index, O/C ratios, unsaturated aliphatics, and peptides, but lower average H/C ratios compared to surface water DOM across locations with different marsh plant species (rice (Oryza sativa), reed (Phragmites australis), Seablite (Suaeda Salsa)) and salinity (0.5 to 51.5 psu). The results suggest that selective preservation for polyphenols, lignin degradation intermediates (highly unsaturated compounds), and microbial resynthesis of heteroatomic compounds are involved in the processing of DOM from surface water to pore water, leading to the formation of higher molecular weight and sulfur-containing molecules. The abundant CHOS compounds could be related to the early diagenetic sulfurization of DOM in sediments. Our unique data set should provide new clues for a comprehensive understanding of the molecular dynamics of DOM in coastal wetlands.

Assessment of heavy metal contamination in surface sediments of the west Guangdong coastal region, China.

Heavy metals (As, Cd, Cr, Cu, Hg, Pb, Zn), organic carbon and grain size of 237 surface sediment samples and one sediment core, taken from the west Guangdong coastal region in January 2008, were analyzed to evaluate the spatial distribution and pollution status. Results show that the ranges of the measured heavy metal concentrations in sediments are as follows: 8.33-39.49mg/kg for As, 0.1-1.49mg/kg for Cd, 33-108mg/kg for Cr, 11.5-78.8mg/kg for Cu, 0.04-0.26mg/kg for Hg, 21-73mg/kg for Pb, 56-248mg/kg for Zn. The heavy metal enrichment is closely associated with Corg and grain size. Both the metal enrichment factor and geoaccumulation index indicate that there was no detected pollution on metals As, Cr, Cu, Pb in our study area and a slight to moderate contamination of Cd, Hg and Zn. However, As, Cr and Cu have showed a certain risk.