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Intensified industrial activities significantly threaten farmland soil integrity, particularly in salinized regions. However, comprehensive evaluations of soil fertility and contamination by polycyclic aromatic hydrocarbons (PAHs) remain limited. In this study, we assessed soil quality in China’s Yellow River Delta (YRD) by quantifying 13 indicators of soil physicochemical and biological properties, along with 11 PAHs. Our findings reveal that the minimum data set approach provides a robust and comprehensive representation of overall soil fertility. Salinity emerged as the primary limiting factor, with strong correlations between salinity and key ions, highlighting its adverse effects on soil structure and function. Additionally, significant PAH contamination was detected, particularly from benzo[a]anthracene (BaA), fluoranthene (Flu), and chrysene (Chr), as indicated by the Nemerov pollution index. A pronounced negative correlation between the soil quality index (SQI) and the soil environmental index (SEI) underscores the substantial role of PAH pollution in soil degradation. Notably, the SQI integrates both SEI and soil fertility, providing a holistic assessment of soil health. These findings highlight the utility of SQI as a diagnostic tool for evaluating soil degradation and emphasize the need for targeted remediation strategies to address salinity and PAH contamination, thereby promoting soil restoration and agricultural sustainability. [ABSTRACT FROM AUTHOR]

Abstract Intensified industrial activities significantly threaten farmland soil integrity, particularly in salinized regions. However, comprehensive evaluations of soil fertility and contamination by polycyclic aromatic hydrocarbons (PAHs) remain limited. In this study, we assessed soil quality in China’s Yellow River Delta (YRD) by quantifying 13 indicators of soil physicochemical and biological properties, along with 11 PAHs. Our findings reveal that the minimum data set approach provides a robust and comprehensive representation of overall soil fertility. Salinity emerged as the primary limiting factor, with strong correlations between salinity and key ions, highlighting its adverse effects on soil structure and function. Additionally, significant PAH contamination was detected, particularly from benzo[a]anthracene (BaA), fluoranthene (Flu), and chrysene (Chr), as indicated by the Nemerov pollution index. A pronounced negative correlation between the soil quality index (SQI) and the soil environmental index (SEI) underscores the substantial role of PAH pollution in soil degradation. Notably, the SQI integrates both SEI and soil fertility, providing a holistic assessment of soil health. These findings highlight the utility of SQI as a diagnostic tool for evaluating soil degradation and emphasize the need for targeted remediation strategies to address salinity and PAH contamination, thereby promoting soil restoration and agricultural sustainability.

In this study, geostatistical techniques were used to investigate spatial variability of physico-chemical properties of soil samples from farming- and artisanal gold mining-affected areas. Based on coefficients of variation, chemical properties, except pH, had high variability compared to physical properties. This could be attributed to the local lithology, vegetation cover and land-use. Spatial distribution patterns of silt, clay, total nitrogen, pH and C/N could be controlled by extrinsic factors such as biological activity and land-use patterns, whereas those of electrical conductivity, organic matter (SOM) and sand were governed by both intrinsic and extrinsic factors. Because of the dominance of clay type, the distribution of cation exchange capacity (CEC) was spatially correlated with clay. About 80% of the area had acidic to circumneutral pH, which may increase mobility and toxicity of most cationic heavy metals. Distribution maps showed that microbial activities, expressed as C/N ratios, tend to be weak around farmlands, reflecting the impacts of soil management practices. In contrast, abundance of clay around the river bank is an indication of soil erosion and its redistribution from upland to depositional areas. Mean error and root mean square error of kriging were higher than those of cokriging for SOM, suggesting that cokriging was more reliable for spatial interpolation of this variable. The work reported in this study indicated that that 29%, 77% and 75% of the area had high probabilities to have pH, CEC and SOM contents below which most cationic heavy metals would be mobile and bioavailable in the soils.

BackgroundHeavy metal pollution in cultivated land will affect crop yield and quality, as well as groundwater quality, ecological security, and human health.ObjectiveTo analyze the pollution status of heavy metal elements such as chromium (Cr), copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd), and lead (Pb) in cultivated soils of the Donghe River Basin in Chenzhou City, and to evaluate the environmental quality of local cultivated soil.MethodsA total of 16 samples of cultivated soil from the Donghe River Basin in Chenzhou City were collected, and the contents of Cr, Cu, Zn, As, Cd, and Pb in the samples were determined by inductively coupled plasma mass spectrometry. The Nemerow comprehensive pollution index method (the evaluation indicators included both Nemerow comprehensive pollution index and single pollution index), the geological accumulation index method, and the potential ecological risk index method were used to evaluate the soil environmental quality.ResultsThe average levels of Cr, Cu, Zn, As, Cd, and Pb in the soil samples in the study area were 58.25, 49.50, 273.88, 137.76, 2.92, and 672.29 mg·kg−1, respectively. The average values of Cu, Zn, As, Cd, and Pb were all exceeded the background values of soil elements in Hunan Province. The single pollution indices of As, Cd, Pb, and Zn in soil were 4.40, 9.74, 5.85, and 1.15 respectively. The contamination of As and Pb reached 93.75% and 81.25% respectively. The geological accumulation indices of soil As, Cd, Pb, and Zn were 2.11, 3.71, 2.97, and 0.58, respectively, which showed heavy Cd pollution, moderate As and Pb pollution, and slight Zn pollution. The potential ecological hazard indices of soil Cr, Cu, Zn, As, Pb, and Cd were 1.63, 9.07, 2.90, 87.75, 113.18, and 695.76. 81.Twenty five percent of Cd samples showed heavy pollution and above, and 62.50% of Pb samples had moderate pollution and above. The Nemerow comprehensive pollution index was 7.72, which belonged to heavy pollution; and the comprehensive potential ecological risk index was 910.29, which belonged to high ecological risk.ConclusionThere are certain differences in the results of different evaluation methods. The cultivated soils of the Donghe River Basin in Chenzhou City, is seriously polluted by heavy metals, and Cd, As, and Pb are the main polluting elements.

Trace elements in farmland soil are important indicators of soil quality and farmland health, and also maintain the nutrient balance and promote the healthy growth of plants. In this study, taking Conghua District of Guangzhou city as the study area, the effects of topography, soil, land use, and other factors on trace elements in soil were investigated, and the spatial variability of boron (B), manganese (Mn), molybdenum (Mo), copper (Cu), and zinc (Zn) in farmland soil in a typical red soil region were mapped using a geographically weighted regression (GWR) method. The pH and land economic index (LEI) were important factors affecting the changes in trace element concentrations in the five soils, and the Cu and Zn concentrations were clearly affected by human factors. In the study area, 86.99% of B measurements were classified as low and very low levels, 50.61% and 49.20% of Mo measurements were also low and very low, 71.79% of Mn measurements were classified as moderate, while 91.02% of Cu and 52.95% of Zn measurements were classified as high. After a cross validation, the GWR Kriging (GWRK) model results of each element were relatively stable, and the order of the fitting coefficient (R2) was Cu > Zn > B> Mn > Mo. This study clarifies the spatial distribution and influencing factors of soil microelements in the studied region. This information can be used to improve the nutrient imbalance, further guide agricultural production, strengthen the management of farmland, and improve the healthy productivity of cultivated land.

This study assessed soil pollution in the Varanasi environs of Uttar Pradesh in India. Assessing the concentration of potentially harmful heavy metals in the soils is imperative in order to evaluate the potential risks to human. To identify the concentration and sources of heavy metals and assess the soil environmental quality, 23 samples were collected from different locations covering dumping, road and agricultural area. The average concentrations of the heavy metals were all below the permissible limits according to soil quality guidelines except Cu (copper) and Pb (lead) in dumping and road soils. Soil heavy metal contamination was assessed on the basis of geoaccumulation index (Igeo), pollution index (PI) and integrated pollution index (IPI). The IPI of the metals ranged from 0.59 to 9.94, with the highest IPI observed in the dumping and road soils. A very significant correlation was found between Pb and Cu. The result of principal component analysis suggested that PC1 was mainly affected by the use of agrochemicals, PC2 was affected by vehicular emission and PC3 was affected by dumping waste. Meanwhile, PC4 was mainly controlled by parent material along with anthropogenic activities. Appropriate measures should be taken to minimize the heavy metal levels in soils and thus protect human health. [ABSTRACT FROM AUTHOR]

Abstract: Over the past few decades, numerous concerns have been raised in China over the issue of environmental sustainability. Various soil survey and monitoring programs have been carried out in China to study soil quality, and to provide a scientific basis for environment policy making. This paper provides an overview of past and current soil quality surveys and monitoring activities in China. This paper includes a summary of concerns over background concentrations of elements in soil, and soil environmental standards and guidelines in China. Levels of pollution in urban soil, agricultural soil, and soil in mining and smelting areas were compared using the concentrations and pollution indexes. In addition to soil surveys, soil monitoring is essential to study the data and to examine the effects of contaminants in soils. However, the current soil quality monitoring system was insufficient to accurately determine the soil quality status of soils across China. For accurate soil monitoring in China, it will be necessary to set up routine monitoring systems at various scales (national, provincial, and local scales), taking into consideration monitoring indicators and quality assurance. This is currently an important priority for the environmental protection administration of China. [Copyright &y& Elsevier]

Identifying the driving factors of soil environmental quality is critical in raising countermeasures for managing the soil environment efficiently and precisely. In 2018, China issued risk control standards to divide soil environmental quality into three classes to meet the demands of environment management. However, there is a lack of knowledge of this new standard. An intensive field-sampling research (2598 top-soil samples were analyzed) was conducted in the agricultural land of Hubei province, central China, to find the driving factors of pollutants based on this new standard. According to the standard, the proportion of classes 1, 2, and 3 in the overall quality grade was 57.3%, 41.7%, and 1%, respectively. The standardized index showed that the pollution levels of cadmium, arsenic, lead, and chromium were higher than that of mercury. The first component of the principal component analysis explained 56.4% of the total variance, and the loading of cadmium, arsenic and lead were -53.5%, -52.1%, and -51.2%, respectively. The general linear modeling found that cadmium and arsenic showed positive and significant effects ( p < 0.001) on the grading results of soil environmental quality. Based on the random forest algorithm, cadmium showed the greatest importance on soil environmental quality (increase in mean squared error = 32.5%). Overall, this study revealed that cadmium, arsenic, and lead were driving pollutants affecting soil environment quality grade. The large data size increased the reliability and robustness of the study's conclusions, and it provided reference methods for future studies investigating China's new standard for assessing soil environmental quality.

Trace elements in farmland soil are important indicators of soil quality and farmland health, and also maintain the nutrient balance and promote the healthy growth of plants. In this study, taking Conghua District of Guangzhou city as the study area, the effects of topography, soil, land use, and other factors on trace elements in soil were investigated, and the spatial variability of boron (B), manganese (Mn), molybdenum (Mo), copper (Cu), and zinc (Zn) in farmland soil in a typical red soil region were mapped using a geographically weighted regression (GWR) method. The pH and land economic index (LEI) were important factors affecting the changes in trace element concentrations in the five soils, and the Cu and Zn concentrations were clearly affected by human factors. In the study area, 86.99% of B measurements were classified as low and very low levels, 50.61% and 49.20% of Mo measurements were also low and very low, 71.79% of Mn measurements were classified as moderate, while 91.02% of Cu and 52.95% of Zn measurements were classified as high. After a cross validation, the GWR Kriging (GWRK) model results of each element were relatively stable, and the order of the fitting coefficient (R2) was Cu > Zn > B> Mn > Mo. This study clarifies the spatial distribution and influencing factors of soil microelements in the studied region. This information can be used to improve the nutrient imbalance, further guide agricultural production, strengthen the management of farmland, and improve the healthy productivity of cultivated land. [ABSTRACT FROM AUTHOR]

Considering the biomagnification in food chains, cadmium (Cd) contamination in paddy fields has become concerning. The remediation of soil cadmium by the addition of amendments is a common agricultural practice. However, it remains ambiguous whether amendment use decreases soil environmental quality (SEQ) and sustainability. In this study, five compound amendments with different pH were utilized in long-term Cd-contaminated paddy soils. The SEQ of all treatments was quantitatively assessed according to a comprehensive evaluation mathematical model (Criteria Importance Through Inter-criteria Correlation (CRITIC)–Technique for Order Preference by Similarity to Ideal Solution (TOPSIS)), and the indicators involved in microbial functional gene (MFG) abundance, soil physicochemical and microbiological properties (CMP) and soil microbial function (N-related enzyme and transformation rate, N-ET) were measured. The results show that the SQE and remediation effect (expressed by the decrease in available Cd (A Cd), %) in our treatments were alkaline > natural > acidic except for D alkaline treatment. The significant contradiction between soil SQE and remediation effect in D treatment attribute to its dose effects, which inhibiting microbial nitrogen assimilation and dissimilation and therefore counteracts the promoting effect of the decrease in A Cd. Based on this discussion, three alkaline amendments (A, B and D) with similar effective remediation effect were employed in four other Cd-contaminated soils. Results indicated that both negative effect (D treatment) and promoting effect (A and B treatment) existed in the next 3 years. [Display omitted] • The new evaluation method effectively reduced the redundancy among indicators. • Underestimating the contribution of microbial functional genes to SEQ assessment. • A significant discrepancy was found between remediation effect and SEQ. • The impact of amendments on SEQ exists for a long time. [ABSTRACT FROM AUTHOR]

Soil pollution has become one of the most important environmental issues in China. It is very important to evaluate soil environmental quality comprehensively and objectively. This paper proposes a soil environment quality assessment model based on the Driving Force-Pressure-State-Impact-Response (DPSIR) model and data fusion. At first, 18 evaluation indicators are selected, including complex indexes, such as the industrialization index, heavy metal pollution index, organic pollution index, potential ecological risk index, and human health risk index, and single indexes such as population density, fertilizer/pesticide application intensity, annual average air quality index, etc. Then, hierarchical analysis model is constructed, and the weight of each indicator is calculated based on Analytic Hierarchy Process (AHP) method. According to the quartile of indicator values of 32 provincial administrative divisions on the Chinese mainland, the values of each indicator are standardized and graded. Finally, the soil environmental quality index (SEQI) is calculated by the weighted average of the standard values of the 18 indicators. The assessment model is then applied in evaluating soil quality of Hebei Province, China. The results show that the soil environmental quality of Hebei's agricultural land is in a medium state, and the industrial land is approaching the alert state. The pressure of soil pollution mainly comes from the discharge of industrial pollutants and the application of pesticides and fertilizers. Soil pollutants, such as lead, copper, zinc, benzo[a]pyrene, and benzo[a] should be especially controlled. [ABSTRACT FROM AUTHOR]