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ice seedlings, and the Cd2+ flux rate in the elongation zone of T705 and X24 roots decreased by 36.0% and 35.0% in 3-day-old seedlings, as well as by 44.6% and 24.9% in 10-day-old seedlings, respectively. In conclusion, Burkholderia sp. Y4 inoculation inhibited the toxic effects of Cd on rice seedling growth through alleviating oxidative stress and damage caused by Cd. Furthermore, the root application of Burkholderia sp. Y4 effectively decreased the Cd2+ flux rate in the elongation zone of roots to inhibit the Cd uptake and accumulation in roots and shoots of rice seedlings. This study provides theoretical basis and data support for the application of Burkholderia sp. Y4 as a Cd-reducing and growth-promoting agent for rice in contaminated farmland.In this study, a field experiment of soil passivation and low accumulation-crops was carried out for typical northern alkaline cadmium and lead compound-polluted farmland soil. Calcite was used as the main passivation material, and a small amount of slaked lime, zeolite powder, and biochar were combined to form a group passivation agent. The effects of passivators on soil physicochemical properties, bioavailability of the heavy metals Cd and Pb, and the yield and plant (stalk and seed) content of heavy metals Cd and Pb in low-accumulation maize were investigated under different grouping conditions of calcite+slaked lime (CL), calcite+zeolite (CZ), calcite+biochar (CB), and calcite+slaked lime+zeolite+biochar (CLZB). The results showed that① all applications of passivating agent ensured the normal growth of maize and slightly increased the 1000 grain weight and maize yield. ② The effects of different calcite-based passivators on soil physical and chemical properties were different. The CL, CZ, CB, and CLZB tress then 0.01). The results showed that the combined use of combination passivators and low-accumulation crop varieties can obtain better restoration effects in the remediation of cadmium and lead combined-polluted farmland in the middle alkaline soil in northern China.Exploring the spatial distribution characteristics and variation law of soil pH and analyzing the impact of environmental factors on the spatial differentiation of soil pH are of great significance to the accurate management of soil pH and the sustainable utilization of soil resources in the complex mountainous environment of Anshun City. Based on 22 851 field sampling points, using the methods of global Moran's I index, cold and hot spot analysis, semi-variance function, and Kriging interpolation, the spatial structure characteristics and distribution law of soil pH in Anshun City were revealed from different angles, and the influence of environmental factors on its spatial differentiation was analyzed with the help of geographic detectors. The results showed that① the variation range of topsoil pH value in Anshun City was 3.56-8.61, the mean value was 6.28, and the coefficient of variation was 16.33%. ② In the global space, soil pH showed aggregation distribution; in the local space, the west and northwest herefore, soil type and parent rock type were the main controlling factors of soil pH spatial variation in Anshun City.In order to study the current status of heavy metal pollution, the accumulation capacity of farmland Sphagnum for heavy metals and the source of heavy metal pollution in the soil near Gaozhai Reservoir in Maojian Tea Town, Duyun City, Guizhou Province were assessed. Sphagnum and topsoil near this area were selected as the research object to measure the content of heavy metals. Spatial analysis and multivariate statistical analysis methods were used to conduct pollution evaluation and source analysis of heavy metals. The results showed that the heavy metal content in topsoil and farmland Sphagnum were V>Zn>Cr>Pb>Cu>Ni>As>Cd>Hg and Zn>Cr>Ni>Cu>Pb>V>As>Cd>Hg, respectively. The dominant species of Sphagnum in the study area were Sphagnum palustre L. ssp. palustre and Sphagnum ovatum Hamp.C.Muell, both of which had a strong ability to accumulate soil Cd, Ni, Cu, and Zn; however, the S. ovatum enrichment capacity of soil heavy metals was generally higher than that of the latter. Both the single pollution index (Cf) and the geo-accumulation index (Igeo) indicated that the Cd and Hg content in soil were at the highest levels, and the average comprehensive pollution index RI was 87.75, which indicates a slight ecological risk. The sources of heavy metals in soil and Sphagnum included transportation, domestic sewage, agricultural activities, and natural soil-forming processes.In order to explore the spatial distribution and ecological risk of heavy metals in farmland soil around Tongguan Mining area, surface soil samples from Tongguan Mining area were collected in September 2020, and the contents and distribution characteristics of eight heavy metals (Pb, Cu, Cd, Hg, Cr, Ni, Zn, and As) in the samples were analyzed. The Nemerow comprehensive pollution index and potential ecological risk index were used to evaluate soil pollution. The results showed that the contents of the eight types of heavy metal elements in this area exceeded the standard, and the exceeding rates were 97.91%, 84.79%, 100%, 95.41%, 96.87%, 98.54%, 91.45%, and 28.95%, respectively. The variation coefficients of the eight heavy metals were ranked as Hg>Pb>Cu>Cd>Zn>As>Ni>Cr. The variation coefficients of Hg, Pb, Cu, Cd, and Zn were all greater than 1. Correlation analysis showed that these five heavy metals were obviously correlated. In terms of spatial distribution, Pb, Cd, Cu, Hg, Zn, and As were distributed in data support for regional pollution control, soil remediation, and ecological protection. It is suggested that the state of soil heavy metal pollution and its transformation in various media should be monitored continuously in the future.The high geological background and the residual pollution of historical zinc smelting in the karst area of northwest Guizhou has led to serious soil heavy metal pollution. In order to understand the characteristics of soil heavy metal pollution in agricultural land, wasteland, and forestland, 126 surface and profile soil samples were collected from a typical zinc powder factory-polluted small watershed in Weining County, Northwest Guizhou Province. The concentrations and distribution characteristics of Cd, As, Pb, Cu, and Zn in soils were studied. The results showed that the average ω(Cd), ω(As), ω(Pb), ω(Cu), and ω(Zn) in the surface soil were 8.14, 45.07, 263.97, 41.36, and 716.98 mg·kg-1, respectively, which were 1.29-12.33 times higher than the background values. The content of heavy metals in soil of different land uses in descending order was agricultural land, wasteland, and forestland. From the perspective of spatial distribution, the soil with high heavy metal concentration was concentrated around th agricultural land was higher than that in wasteland and forestland. BRD0539 In the karst high geological background area, the influence of lead and zinc smelting on the distribution and accumulation of heavy metals in soils was greater than that of land use; soil heavy metal pollution was serious, and ecological risk was high in this area. Therefore, strict control of heavy metal-contaminated soil should be strengthened.Carbonatite and basalt are widely distributed in southwest China, and potentially toxic elements (PTEs) are associated with the naturally high background properties. It is important to carry out ecological risk assessments and identify potential sources of PTEs. A total of 3180 soil samples (0-20 cm) were collected in Hezhang county, a typical high background area of PTEs with the parent lithology of carbonatite and basalt. Samples were obtained from 18 large lead-zinc mines, which belong to a multi-ecological risk superimposed area with high ecological risk. The concentration of PTEs (Cd, Cr, As, Hg, Pb, Cu, Zn, and Ni) in the topsoil were analyzed, and statistical analysis (SA), geographic information system (GIS), enrichment factor (EF), potential ecological risk index (RI), and positive matrix factorization (PMF) methods were used to assess the ecological risk and quantify sources of PTEs. The mean values of PTEs concentrations in topsoil were 24.55, 2.25, 176.40, 89.60, 0.19, 64.20, 102.00, and 257.00 mge mining areas expectedly contained high ratios of Zn/Cd and Pb/Cd, which confirmed that PTEs in the soil were mainly derived from the smelting wastes. The contents of metal oxides such as Fe, Mn, and Si were the influencing factors of PTEs enrichment. On the contrary, soil samples exhibited much lower Zn/Cd and Pb/Cd ratios in non-mining areas, indicating that the main origin of these metals in soil was the smelting flue gas dusts and geological background.The concentrations of rare earth elements (REEs) in protected vegetable soils in Wuqing district of Tianjin City, Jinzhong district of Shanxi Province, Shenyang district of Liaoning Province, and Wulanchabu district of Inner Mongolia Autonomous Region in northern China were measured to analyze the change characteristics of soil REEs in the process of protected vegetable cultivation. Additionally, we sought to use the REEs parameters to trace the feasibility of characterizing the interference of human activities on the soil ecological environment. The results showed that the total content of REEs (REE) in the topsoil of protected vegetable fields ranged from 146.52 to 158.76 mg·kg-1, with an average of 152.34 mg·kg-1 in Shenyang; 92.16 to 137.69 mg·kg-1, with an average of 115.03 mg·kg-1in Wuqing; 91.38 to 118.84 mg·kg-1, with an average of 108.03 mg·kg-1 in Wulanchabu; and 97.62 to 111.27 mg·kg-1, with an average of 102.43 mg·kg-1in Jinzhong. The REEs distribution patterns in the soils of the four areas, stanmong light rare earth elements in soil. Higher δCe values and lower δEu values suggested that Ce and Eu were relatively enriched and depleted, respectively, during vegetable planting. The REE, LREE, (La/Sm)N, and δEu in protective soil decreased with the number of cultivation years, whereas the (Gd/Yb)N and δCe increased, but the HREE values did not change significantly. There was a significant correlation between δCe, δEu, (La/Yb)N, (Gd/Yb)N, and soil bulk density, soil moisture content, and soil organic matter in Tianjin protected vegetable soils, showing preliminarily that rare earth elements can be used as tracer elements to characterize the interference intensity of human activities on soil.The Yangtze River Economic Belt is one of the areas with rapid economic development in China, although the intensive industrial activities have aggravated the emissions of soil pollutants in this area. Industrial activities are important sources of soil heavy metal contamination; however, the spatial distribution and main emission sources of soil heavy metal contamination in industrial regions of the economic belt remain unclear. Here, we collected data on the concentrations of eight heavy metals (Cd, Cr, Cu, Pb, Ni, Hg, As, and Zn) in the surface soils of 193 industrial regions covering 11 provinces and cities of the Yangtze River Economic Belt from China National Knowledge Infrastructure (CNKI), Web of Science, and other public databases. On this basis, we analyzed the spatial distribution characteristics of heavy metals and the contamination characteristics of typical industries. The results showed that the heavy metal contamination in agricultural land was more serious than that in industrial land. A total of 58.