Soil Ecological Risk Research Articles

Heavy Metal Pollution Characteristics and Risk Assessment of Soil-crop System in Gold Mine Activity Area

A contamination analysis was conducted on the soil and crops in the Liu Jia Dian gold mining area of the Pinggu District, Beijing, utilizing the contents and seven-step forms of heavy metals （Hg, Cd, Cr, Pb, and As） in soil and the heavy metal contents in crops at the same location. An assessment of ecological risk caused by heavy metal contamination in the soil and crops was carried out using the enrichment coefficient method and the risk assessment coding method. The study investigated the process of heavy metal absorption and enrichment in the soil-crop system, aiming to establish a scientific foundation for preventing and controlling soil pollution, as well as ensuring the safety of edible crops in the study area. Evidence indicated the presence of soil contamination by heavy metals in the study area, with Cd, Pb, and As being the primary pollutants. Moreover, the distribution of pollution levels could be categorized as severe, moderate, and mild, with proportions of 26.09%, 4.35%, and 10.87%, respectively. The content of each heavy metal decreased following the implementation of environmental governance； however, the ecological risk remains present. Hg, Cr, Pb, and As posed minor ecological risks； however, Cd had a high ecological risk, making it the primary soil ecological risk factor. Fruits, nuts, and cereals in the Pinggu gold mining area remained uncontaminated. Various degrees of contamination were found in melons, rhizomes, and leafy vegetables. The Chinese cabbage, Chinese chive, radish, and eggplant were heavily contaminated, with Cd and Pb being the primary sources of contamination. The accumulation of heavy metals in crops was intricately linked to gold mines and their mining operations. The accumulation of Cd in crops was mainly influenced by the high availability of Cd in soil, whereas the accumulation of Pb was mainly influenced by the high concentration of Pb in the soil. The concentration of heavy metals in the soil and their bioavailability in the Pinggu gold mining area indicated the accumulation of metal elements in crops and impacted the geographical distribution of heavy metal pollution in crops. The physiological characteristics of crops could affect the degree of heavy metal enrichment in the gold mining area. The order of heavy metal accumulation, from highest to lowest, was as follows： leafy vegetables, melons, rhizomes, cereal, fruits, and nuts. Peppers and eggplants were limited in their planting variations for melons, while leeks and cabbages were restricted for leafy vegetables, given the current agricultural planting conditions in the study area.

New mechanistic insights into soil ecological risk assessment of arsenite (III) and arsenate (V)：Cellular and molecular toxicity responses in Eisenia fetida

Inorganic arsenic (iAs) is a persistent bioaccumulation carcinogen that is most abundant in soils in the form of arsenite-As (III) and arsenate-As (V). However, there is currently very little explicit evidence about cytotoxicity of As on soil organisms. Moreover, toxicological data for iAs and proteotoxicity is shortage. The purpose of the present work is to elucidate the cytotoxicity mechanism of As (III) and As (V) to earthworms, a soil ecological sentinel species, and the molecular mechanisms by which As (III)/As (V) directly bind to antioxidative enzyme Cu/Zn-superoxide dismutase (Cu/Zn-SOD). Results indicate that iAs triggered cell membrane injury and genotoxicity. As (V) (56.15 %) induced lower cell viability than As (III) (61.88 %). Higher ROS and lipid peroxidation level in As (V) support greater cytotoxicity. Differences in cellular uptake due to valence induced diverse levels of oxidative stress and cytotoxicity. At the molecular level, As (III) (129.33 %) induced higher Cu/Zn-SOD activity than As (V) (110.75 %). Changes in backbone, secondary structure, amino acid microenvironment and particle size of Cu/Zn-SOD further revealed the mechanisms of differential molecular toxicity of As (III) and As (V). Binding reactions with Cu/Zn-SOD explain differences in molecular toxicity. Collective research showed that iAs-induced oxidative stress and binding reactions determine the difference of SOD activity between As (III) and As (V) at the cellular level. This work offers new insights into the health risk assessment of As.

Effects of land use types on the soil physicochemical characteristics of Inyi community, Enugu State, Nigeria: Application of multivariate statistical, and eco-toxicological and human risk model approaches

The constant and increased use of arable lands for cultivation has led to its degradation; hence the impacts of different land-use patterns on the soil physical and chemical properties were investigated. Soil samples (n = 36) were collected from the oil palm plantation (OPP), cashew plantation (CP) and untampered forest (UF), in Inyi community, Enugu State, Nigeria. They were air-dried, sieved, and analyzed for their physicochemical properties. The results revealed that the average soil pH ranged from 5.9 to 8.2. Moisture and carbon contents ranged from 6.3 to 35.4, and 3.5 to 6.7 % respectively. Low CEC values were recorded for all the soil samples. The total mean soil textural fractions decreased as follows: sand > clay > silt. Also, the total mean concentrations of N, P, K, and Mg in the study area decreased in the order: OPP>UF>CP, OPP>UF>CP, UF>OPP>CP, and OPP>UF>CP respectively while the S, NO3-, NO2-, and HCO3- followed the order; OPP>UF>CP, UF>OPP>CP, OPP>CP>UF, and CP>OPP>UF respectively. The soil ecological risk index was < 40 in all sample locations, indicating slight contamination of the study area. Therefore, regular monitoring and soil nutrient management practices should be maintained and encouraged.

Characteristics of soil microplastics and ecological risks in the Qilian Mountains region, Northeast Tibetan Plateau

Microplastics (MPs) pollution has become a vital global environmental issue. However, comprehensive understanding of the ecological risks of MPs in soils of Northeast Tibetan Plateau still requires further study. In this study, we used the Agilent 8700 Laser Direct Infrared (LDIR) spectroscopy to analyze the characteristics of 10–1000 μm MPs in soils of different vegetation types throughout the Qilian Mountains basin, and to comprehensively explore the ecological risks of MPs in various ecological environments. The results indicate that MPs abundance is highest in soil of shrub areas (26,369 ± 32,147 items kg−1-dry weight (dw)), followed by woodland (22,215 ± 22,544 items kg−1-dw), desert (17,769 ± 9,040 items kg−1-dw), grassland (16,462 ± 12,872 items kg−1-dw), and forest (15,662 ± 13,857 items kg−1-dw). MPs in soils of different vegetation types show similar physical and chemical characteristics, with the shape dominated by fragments (93%–96%), followed by fibers and a few beads, with dominant sizes of 10–30 μm (63%–76%), and polymers dominated by polyamide (PA) and polyethylene terephthalate (PET). Additionally, the environmental risks posed by the fundamental characteristics of MPs have been quantified through the Pollution Load Index (PLI), Pollution Hazard Index (PHI), and Potential Ecological Risk Index (PERI) models. According to the PLI assessment, the current levels of MPs in the environment have not yet imposed significant burdens on the ecosystem. However, the results of PHI and PERI indicate a higher risk of MPs pollution in the Qilian Mountains. This study offers vital information for MPs pollution in the whole Qilian Mountains regions and their potential environmental risks in remote areas’ soil.

Predicting the ecological risk thresholds of soil metals in Europe using the quantitative ion character-activity relationships (QICAR) model

Metal pollutants have become increasingly diverse. Therefore, managing the ecological risks associated with these elements in soil is urgently required. However, determining the soil ecological risk thresholds of elements through routine toxicological tests is time-consuming and laborious, establishing prediction models is vital to risk management. Accordingly, this study aimed to predict the element toxicity to soil organisms by collecting the toxicological data of eight elements to soil organisms at 18 European and 17 Chinese sites through literature and toxicology databases, using the quantitative ion character-activity relationship (s-QICAR) model. Firstly, the toxicity values (logEC10) of eight elements to five biological species and three microbial processes were obtained through clustering and soil normalization methods in three typical soil scenarios. Correlation analysis revealed that for different species and microbial processes, there are three to six physicochemical properties of elements related to their toxicity, among which, the covalent radius of the element was the best significantly correlated with logEC10 of all organisms (R2 = 0.77–0.95). Based on this, the s-QICAR model was established and used to predict the logEC10 of Sc, Ti, V, Cr, Co, Ni, Cu, and Zn to eight organisms. Furthermore, along with the species sensitivity distribution curve, the HC5 values (i.e., 95% species protection level) for the above eight elements were calculated. Following correction, the predicted no-effect concentrations of these elements ranging from 9 to 189 mg/kg, and the ecological risk threshold map has been produced. In summary, we present a new method to quantify the ecological risk of metal-induced pollution in European soils without routine toxic measurements, and provide important insights into soil pollution risk assessment and management.

Rapid detection and risk assessment of soil contamination at lead smelting site based on machine learning

A general prediction model for seven heavy metals was established using the heavy metal contents of 207 soil samples measured by a portable X-ray fluorescence spectrometer (XRF) and six environmental factors as model correction coefficients. The eXtreme Gradient Boosting (XGBoost) model was used to fit the relationship between the content of heavy metals and environment characteristics to evaluate the soil ecological risk of the smelting site. The results demonstrated that the generalized prediction model developed for Pb, Cd, and As was highly accurate with fitted coefficients (R2) values of 0.911, 0.950, and 0.835, respectively. Topsoil presented the highest ecological risk, and there existed high potential ecological risk at some positions with different depths due to high mobility of Cd. Generally, the application of machine learning significantly increased the accuracy of pXRF measurements, and identified key environmental factors. The adapted potential ecological risk assessment emphasized the need to focus on Pb, Cd, and As in future site remediation efforts.

Soil pollution identification and human health risk assessment of soil heavy metals in an abandoned mine area in the Republic of Korea

ABSTRACT In this study, the Geo-accumulation index (Igeo), Human Health Risk Assessment (HRA), and Ecological Risk Index (ERI) were utilized to examine the risks associated with the soils at the DaeyangYeongseong mine. Brassica juncea and Raphanus sativus were employed in the ecological toxicity test. In all soil samples, the mean Igeo value of arsenic measured 3.15, and cadmium measured 6.63, indicating a very high level of heavy metal contamination. The carcinogenic risk of cadmium and arsenic for adults was 4.30×10−3 and 1.43×10−5, respectively. For children, these values were 3.92 × 10−2 and 1.33 ×10−4, exceeding the acceptable level (1×10−6). In all soils, cadmium showed extremely high ecological risk levels, and arsenic had extremely high risk levels in 34.8% of the total area. This was also confirmed in toxicity assessments using plants. Therefore, arsenic and cadmium were found to be the main causes of soil contamination and ecological risk.

Unraveling the Distribution, Metabolization, and Catabolism of Foliar Sprayed Carbon Dots in Maize and Effect on Soil Environment.

The enormous potential of carbon dots (CDs) in agriculture has been widely reported, whereas their accurate distribution, transformation, and metabolic fate and potential soil health effects are not clearly understood. Herein, 13C-labeled CDs (13C-CDs) were sprayed on maize leaf, accumulated in all tissues, and promoted photosynthesis. Specifically, 13C-CDs were internalized to participate in the synthesis of glucose, sucrose, citric acid, glyoxylate, and chlorogenic acid, promoting tricarboxylic acid cycle (TCA) and phenylalanine metabolism. Additionally, the catabolism of 13C-CDs in vivo was mainly mediated by O2•- produced by oxidative stress. 13C-CDs did not have an obvious impact on the soil environment at the overall level. The detection of 13C signals in soil fauna suggested 13C-CDs in soil food chain transmission. This study systematically described the exact fate of CDs in plants and potential soil ecological risks and provided a more comprehensive analysis and support for the potential advantages of CDs in agricultural application.

Assessment of heavy metal(oid) pollution and related health risks in agricultural soils surrounding a coal gangue dump from an abandoned coal mine in Chongqing, Southwest China

The coal gangue dump may introduce heavy metal(oid)s (HMs) into surrounding agricultural soils, posing potential health risks to nearby communities. This study evaluated heavy metal(oid) pollution in agricultural soils adjacent to a gangue dump at an abandoned coal mine in Chongqing, Southwest China. The concentrations of HMs (As, Cd, Cr, Cu, Ni, Pb, and Zn) were quantified using ICP-MS, and the contamination status was assessed using the Geoaccumulation Index (Igeo), Contamination Factor (CF), Pollution Load Index (PLI), and Potential Ecological Risk Index (RI). Heavy metal(oid) contamination was detected in soils across a depth of 0–30 cm, particularly pronounced in the topsoil layer (0–10 cm and 10–20 cm depths). Cu emerged as the predominant contaminant across all examined depths, with average Igeo values of 1.20, 1.21, and 1.16 for the 0–10 cm, 10–20 cm, and 20–30 cm depths, respectively, indicating moderate contamination. The CF for Cu was 3.55, 3.55, and 3.50 for these respective depths, classifying it as considerable contamination. The PLI values ranged from 1.61 to 2.50, with a mean value of 2.12, indicating overall contamination. The ecological risk assessment indicated that the soil's ecological risk was low at all depths. Cd was the major contributor to the RI, accounting for 48%, 47%, and 42% at 0–10 cm, 10–20 cm, and 20–30 cm depths, respectively. Health risk assessments revealed significant non-carcinogenic risks to children (mean HI = 1.30) and unacceptable carcinogenic risks to both adults and children (mean TCR = 3.26 × 10–4 and 1.53 × 10–3, respectively). This study underscores the critical need for comprehensive risk assessments using multiple indicators to prioritize remediation efforts for HMs, providing a scientific basis for effective environmental management and public health protection in the Three Gorges Reservoir Area.

Hazards of toxic metal(loid)s: Exploring the ecological and health risk in soil–crops systems with long-term sewage sludge application

Sewage sludge (SS) is commonly used as agricultural fertilizer worldwide. However, the toxic metal(loid)s in SS raises concerns about soil contamination and the potential risks to human health. This study, conducted since 2007 on the North China Plain, examines the impact of SS use on crops. An experiment was designed with five treatments: conventional fertilization (CK) and four levels of SS application (W1, W2, W3, and W4: 4.5, 9.0, 18.0, and 36.0 t ha−1, respectively). Soil concentrations of eight toxic metal(loid)s (Zn, Cu, Cr, Cd, Ni, Pb, As, and Hg) were analyzed to assess pollution risk using various indices. Health risks associated with maize and wheat grains were also evaluated. Additionally, the impact of long-term SS application on crop yield, soil quality, and human health within a wheat-maize rotation system was examined. SS application increased wheat and maize yields by 5.37 to 19.08 % and 6.97 to 17.94 %, respectively, across treatments W2 to W4. Despite the toxic metal(loid)s in the grains remaining within safe limits, their concentrations showed an upward trend, especially under the W4 treatment. Moreover, SS application significantly increased the soil Zn, Cu, Cr, Cd, Pb, and Hg levels (P < 0.05) without exceeding the national standards. The geo-accumulation index values revealed rising pollution levels for Zn, Cu, Cd, and Hg, which shifted from no contamination to moderate contamination and then to moderate-to-high contamination, yet the overall pollution level remained safe. Soil ecological risks increased from moderate to serious, with Hg posing the greatest risk, particularly under the W4 treatment. Long-term crop intake from the area significantly exposed children and adults to As, contributing 42.12 % and 34.62 % to hazard index (HI), respectively. The HI values for toxic metal(loid)s in these grains surpassed one in both age groups, suggesting health risks from long-term SS cultivated crops.

Native plant species growing on the abandoned Zaida lead/zinc mine site in Morocco: Phytoremediation potential for biomonitoring perspective.

This study aims to assess the level of metal contamination and the ecological risk index at the abandoned Zaida Pb/Zn mining site in eastern Morocco and identify native plant species found on the site that can be used in site rehabilitation through phytoremediation strategies. Samples from seven native and abundant plant species at the site, along with their rhizospheric soils, were collected and analyzed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) to determine the concentrations of various metal(loid)s, including As, Cu, Ni, Cd, Sb, Zn, and Pb. Indicators of soil pollution and ecological risks were also assessed, including the enrichment factor (EF), pollution index (PI), and ecological risk index (ERI). The Biological Accumulation Coefficient (BAC), Translocation Factor (TF), and Biological Concentration Factor (BCF) of plant samples were calculated. The results reveal polymetallic soil contamination, with notably higher concentrations of Pb, Cu and Zn, reaching respectively 5568 mg kg-1 DW, 152 mg kg-1 DW, and 148 mg kg-1 DW, indicating a significant potential ecological risk. The enrichment factor (EF) was also assessed for each metal(loid)s, and the results indicated that the metal contamination was of anthropogenic origin and linked to intensive mining activities in Zaida. These findings are supported by the pollution index (PI) ranging from 1.6 to 10.01, which reveals an extremely high metal(loid)s pollution level. None of the plant species exhibited a hyperaccumulation of metal(loid)s. However, Artemisia herba alba demonstrated a strong capacity to accumulate Pb in its aboveground parts, with a concentration of 468 mg kg-1 DW. Stipa tenacissima, Retama spherocarpa, and Astragalus armatus, showed a significant Pb accumulation in their roots reaching 280, 260, and 256 mg kg-1 DW.respectively. Based on BAC, TF, and BCF, Stipa tenacissima exhibited potential for Ni and Cd phytostabilization, as well as the ability for Zn phytoextraction. Additionally, Artemisia herba alba displayed the capability to phytoextract Cd and had a high propensity to translocate all the studied metal(loid)s. Astragalus armatus has the potential to be used in the phytostabilization of Zn and Ni, as well as for the phytoextraction of As and Sb. These native species from the Zaida site, although not hyperaccumulators, have the potential to contribute significantly to the phytoextraction or phytostabilization of potentially toxic elements (PTEs). Moreover, they can serve as vegetative cover to mitigate the erosion and dispersion of metal(loid)s.

Soil ecological risk assessment of ten industrial areas in China based on the TRIAD and VIKOR methods

The TRIAD approach is widely used as a scientific methodology available to deal with site-specific contamination scenarios. In this study, a soil environmental risk assessments (SERA) of ten industrial sites in China was conducted by ranking risks across multiple sites based on the TRIAD method, and attempted to provide an alternative method for risk ranking, the VIKOR method, when reference screening values for assessing individual indicators are unavailable. The VIKOR method was developed to address ranking and selection problems in multi-criteria decision-making, particularly in complex decision environments. The present assessments analyzed 33 chemical analysis indicators, 14 ecotoxicological indicators, and 5 ecological indicators related to soil microbial diversity, subsequently compared and discuss the differences in risk ranking results obtained using the two methods. The results of the TRIAD approach showed that six sites (including F, G, E, B, J and I) were ranked high in the risk order, which were in the moderate-risk range (Integrated risk value, 0.5–0.75). While the results of the VIKOR method showed that four sites (including F, G, H, and E) were ranked high in the risk order, followed by another four sites (including D, A, B, and C). Although there were differences in the assessment results, both methods consistently identified three sites (including F, G, and E) with relatively higher risks. The results indicated that when the TRIAD method is not applicable in special cases, the VIKOR comprehensive evaluation can be used to infer the relative ecological risk of the assessed site.

A Monte Carlo simulation-based health risk assessment of heavy metals in soils of the tropical region in southern China.

The disturbance of ecological stability may take place in tropical regions due to the elevated biomass density resulting from heavy metal and other contaminant pollution. In this study, 62 valid soil samples were collected from Sanya. Source analysis of heavy metals in the area was carried out using absolute principal component-multiple linear regression receptor modelling (APCS-MLR); the comprehensive ecological risk of the study area was assessed based on pollution sources; the Monte-Carlo model was used to accurately predict the health risk of pollution sources in the study area. The results showed that: The average contents of soil heavy metals Cu, Ni and Cd in Sanya were 5.53, 6.56 and 11.66 times higher than the background values of heavy metals. The results of soil geo-accumulation index (Igeo) showed that Cr, Mo, Mn and Zn were unpolluted to moderately polluted, Cu and Ni were moderately polluted, and Cd was moderately polluted to strongly polluted. The main sources of heavy metal pollution were natural sources (57.99%), agricultural sources (38.44%) and traffic sources (3.57%). Natural and agricultural sources were jointly identified as priority control pollution sources and Cd was the priority control pollution element for soil ecological risk. Heavy metal content in Sanya did not pose a non-carcinogenic risk to the population, but there was a carcinogenic risk to children. The element Zn had a high carcinogenic risk to children, and was a priority controlling pollutant element for the risk of human health, with agricultural sources as the priority controlling pollutant source.

Heavy metal spatial distribution, source analysis, and ecological risks in the central hilly area of Hainan Island, China: results from a high-density soil survey.

The presence of heavy metals in soil has gained considerable attention due to their potential risks to ecosystems and human health. In this study, a thorough soil investigation was performed in the hilly region of central Hainan, which was formerly regarded as an area with the highest ecological environmental quality. A total of 7094 soil samples were systematically collected with high density over a large area. Simultaneously, a detailed investigation was conducted on the surrounding environment of each sampling point, including environmental factors such as soil, land use and crop types. The soil samples were analysed for heavy metals, pH, organic matter, and other parameters. The soil heavy metal pollution level, ecological risk and health risk were evaluated using the geo-accumulation index and the potential ecological risk index. The findings showed that the average contents of the heavy metals As, Cd, Cr, Cu, Hg, Ni, Pb and Zn in the soil were 1.68, 0.042, 24.2, 6.49, 0.0319, 7.06, 29.6 and 49.8mg·kg-1 respectively. Except for Hg, the mean values of the other heavy metals were either lower than or similar to the background values of Hainan. Also, only a few localised areas showed contamination by heavy metals. The primary sources of heavy metals, identified by a positive matrix factorisation model, could be categorised into four types: natural sources related to the soil formation process from acidic intrusive rocks (such as granite); natural sources primarily influenced by atmospheric deposition; anthropogenic sources associated with agricultural activities; and natural sources related to the soil formation process from middle-mafic intrusive rocks and black shales. The correlation analysis and variance analysis findings suggested that the content of heavy metals in the soil was primarily associated with the parent rock. The study area generally had low heavy metal levels and was not significantly polluted. However, agricultural activities still affected the enrichment of heavy metals. Therefore, it is imperative to remain vigilant about the ecological risks linked to soil heavy metals while continuing land development and expanding agricultural activities in the future. These findings indicate that conducting high-density soil surveys can enhance our understanding of regional soil heavy metals and enable reliable recommendations for agricultural planning. Whether in areas with low pollution risk or potential pollution risk, it is recommended that high-density soil surveys be conducted provide scientific guidance for further agricultural development.

Comparative assessment of copper pollution, bioavailability, and ecological risks in soil-cacao systems under organic versus conventional management

The continuous use of fertilizers and fungicides has triggered copper (Cu) contamination in cacao soils in Ghana, which is a critical issue for the ecological risk and health safety of cacao products. In this study, we investigated Cu pollution, bioavailability, and ecological risk in soil and determined the Cu levels in the cacao nib, shell, and pod husk. Soils were collected at two soil depths (0–15 ​cm and 15–30 ​cm) from 20 cacao farms, under conventional (CCM: chemical-based fertilizers) and organic (OCM: organic-based fertilizers) management practices together with pods. The total Cu concentration ranged from 67.6 to 96.8 ​mg ​kg−1 in OCM and 28.5–33.9 ​mg ​kg−1 in CCM soil, which decreased with soil depth. The enrichment factor revealed minimal Cu enrichment, which was attributed to anthropogenic activity (fungicide and fertilizer applications). The contamination factor and geoaccumulation index values were low for the CCM soils, and moderate for the OCM soils. Both management systems pose a low potential ecological risk to soil biota activity. Bioavailable Cu extracted with CaCl2, NH4OAc, and DTPA was dominant in CCM soil and decreased with soil depth. The Cu concentration in cacao plants decreased in the order of shell > pod husk > nib, with nib-Cu being below the threshold (50.0 ​mg ​kg−1) of contamination. The results from the pairwise correlation analysis show that CaCl2-available Cu is better for evaluating the Cu content in cacao plants. This study reveals the pollution levels associated with cacao management practices, thus providing valuable insights for developing appropriate mitigation strategies.

Assessment of Heavy Metal Contamination and Ecological Risk in Soil within the Zheng–Bian–Luo Urban Agglomeration

As urbanization accelerates, the contamination of urban soil and the consequent health implications stemming from urban expansion are increasingly salient. In recent years, a plethora of cities and regions nationwide have embarked on rigorous soil geological surveys with a focus on environmental quality, yielding invaluable foundational data. This research aims to develop scientifically robust and rational land-use planning strategies while assessing the levels of heavy metal pollution and associated risks. The urban agglomeration encompassing Zhengzhou, Luoyang, and Kaifeng (referred to as Zheng–Bian–Luo Urban Agglomeration) in Henan Province was designated as the study area. Leveraging the Nemerow comprehensive index method alongside the Hakanson potential ecological risk assessment method, this study delved into the pollution levels and potential ecological ramifications of nine heavy metals, namely Cr, Mn, Ni, Cu, Zn, As, Cd, Pb, and Co. Research indicates that the hierarchy of individual potential ecological risks ranges from most to least significant as follows: Cd &gt; Pb &gt; Cr &gt; Ni &gt; Cu &gt; Zn &gt; As &gt; Mn &gt; Co. The concentrations of Cd in both Zhengzhou and Kaifeng surpassed the established background levels. Furthermore, the mean single-factor pollution index values for the heavy metals Cd and Zn exceeded 1, signifying a state of minor pollution. The Nemerow comprehensive index P of Cd and Zn is between 1 &lt; Pcomp ≤ 2, which is considered mild pollution. The comprehensive P values of the other seven metal elements are all less than 0.7, reaching a clean (alert) level. Predominantly, the primary potential risk factor in the superficial soil of the Zheng–Bian–Luo urban agglomeration is Cd, while the ecological risk implications associated with other heavy metal elements are comparatively minimal. The soil environmental quality within the designated study area remains secure, although certain localized areas pose potential risks of heavy metal pollution. A comprehensive assessment of the current state of soil heavy metal pollution is essential to establish a theoretical foundation and provide technical support for soil environmental protection, pollution mitigation, and sustainable utilization.

Ecological Risk Assessment of Three Pesticide Additives in Soil and Application to the Remediation of Contaminated Soil.

Pesticide additives (PAs) are auxiliary ingredients added to the pesticide manufacturing and use processes, constituting 1% to 99% of the pesticide and often composed of benzene and chlorinated hydrocarbons. We selected three typical PAs, toluene, chloroform, and trichloroethylene, to evaluate their retention function toxicity and ecological risk in soil. Soil immobilization techniques and aquatic model organisms were used to demonstrate the effectiveness of the immobilized soil method to determine the ecological risk of chemicals. The 48-h median lethal concentrations of toluene, chloroform, and trichloroethylene alone in spiked soil on Daphnia magna were 10.5, 2.3, and 1.1 mg/L (medium, high, and high toxicity, respectively). The toxicity of the three-PA mixtures showed an antagonistic effect. The risk levels of toluene, chloroform, and trichloroethylene in the soil were evaluated as moderate to high, low to high, and high risk, respectively. The toxicity of two pesticide-contaminated sites in the Yangtze River Delta before and after remediation was successfully evaluated by immobilized soil technology. The toxicity of two soil sampling points was reduced from medium toxic to low toxic and no toxic, respectively, after remediation. The results of our study give a rationale for and prove the validity of the aquatic model organisms and soil immobilization techniques in assessing the soil retention functions toxicity of PAs. Environ Toxicol Chem 2024;43:1677-1689. © 2024 SETAC.

Spatiotemporal distribution, sources, and ecological risk of soil polycyclic aromatic hydrocarbons in Chinese urban agglomerations from 2000 to 2020

To investigate the spatial and temporal distribution, sources, and ecological risk of soil polycyclic aromatic hydrocarbons (PAHs) in China’s urban agglomerations from 2000 to 2020, a comprehensive search strategy was employed using the keywords “soil”, “PAHs”, and “city”. A total of 122 relevant studies that provided information on individual PAH content during the specified time period were collected. These studies encompassed 20 urban agglomerations in China, which were further categorized into two distinct periods: 2000 to 2010 and 2011 to 2020. The diagnostic ratio method and principal component analysis were employed to identify the sources of PAHs, and a risk quotient model was used to evaluate the soil ecological risk. The results revealed the average PAH content in the 20 urban agglomerations in China from 2011 to 2020 was 2,439 ± 4,633 ng·g-1, which exceeded the severe pollution level cut-off (&amp;gt; 1,000 ng·g-1). The soil PAH content in the period from 2011 to 2020 decreased by 28% compared to the soil PAH content in the period from 2000 to 2010. Soil PAH pollution was more severe in the northern urban agglomerations than in the southern urban agglomerations. Diagnostic ratios and principal component analysis demonstrated that the principal sources in most urban agglomerations in China were traffic and coal combustion. GeoDetector found that coal and fuel oil consumption were the main factors affecting the spatial differentiation of PAHs. The ecological risk quotient showed that approximately 80% of the urban agglomerations were at a medium-high ecological risk from 2000 to 2010, compared with 72% from 2011 to 2020. Thus, it is necessary to deepen energy structure reform to alleviate the threat of serious pollution caused by coal and fuel oil in urban agglomerations.

Health risk assessment of soil heavy metals in a typical mining town in north China based on Monte Carlo simulation coupled with Positive matrix factorization model

The accumulation of heavy metals (HMs) in soil caused by mineral resource exploitation and its ancillary industrial processes poses a threat to ecology and public health. Effective risk control measures require a quantification of the impacts and contributions to health risks from individual sources of soil HMs. Based on high-density sampling, soil contamination risk indexes, positive matrix factorization (PMF) model, Monte Carlo simulation and human health risk analysis model were applied to investigate the risk of HMs in a typical mining town in North China. The results showed that As was the most dominant soil pollutant factor, Cd and Hg were the most dominant soil ecological risk factors, and Cr and Ni were the most dominant health risk factors in the study area. Overall, both pollution and ecological risks were at low levels, while there were still some higher hazard areas located in the central and south-central part of the region. According to the probabilistic health risk assessment (HRA), children suffered greater health risks than adults, with 21.63% of non-carcinogenic risks and 53.24% of carcinogenic risks exceeding the prescribed thresholds (HI > 1 and TCR>1E-4). The PMF model identified five potential sources: fuel combustion (FC), processing of building materials with limestone as raw materials (PBML), industry source (IS), iron ore mining combined with garbage (IOG), and agriculture source (AS). PBML is the primary source of soil HM contamination, as well as the major anthropogenic source of carcinogenic risk for all populations. Agricultural inputs associated with As are the major source of non-carcinogenic risk. This study offers a good example of probabilistic HRA using specific sources, which can provide a valuable reference for strategy establishment of pollution remediation and risk prevention and control.

Dissipation kinetics, residue level, and risk assessment of chlorantraniliprole in Rosa roxburghii and its residue removal using household decontamination technique

Rosa roxburghii (R. roxburghii) is edible and medicinal fruit rich in vitamin C. Residues and potentially ecological risks of chlorantraniliprole (CAP) in the R. roxburghii orchard have aroused concern considering its extensive use for controlling oriental fruit moth, aphid, and whitefly of R. roxburghii. In this study, an effective UPLC–MS/MS method was developed for quantitation of CAP in R. roxburghii and soil using modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) dispersive solid-phase extraction with average recoveries of 73.89–96.63% and a relative standard deviation of &lt;15%. Dissipation dynamics and terminal residue trials under the field conditions in 2021 and 2022 showed that half-lives of CAP in R. roxburghii (2.64–2.70 days) were shorter than those in soil (3.58–3.80 days), and its terminal residues in R. roxburghii and soil were 0.034–0.818 mg kg-1 and 0.003–0.015 mg kg-1, respectively. Long-term dietary and soil ecological risk assessments indicated that the risk quotient was significantly less than 100%, meaning that the use of CAP on R. roxburghii at the recommended dosage was safe to consumers and soil ecology system, and that maximum residue limits (MRLs) and safe pre-harvest intervals of CAP in R. roxburghii were recommended as 0.7 mg kg-1 and 14 days, respectively. Removal experiments of CAP residues from R. roxburghii using simple household processing approaches exhibit that 2% baking soda water had the highest removal efficiency (56.04–60.33%). This study provides the basic data for establishing MRL, the safe and rational use of CAP in R. roxburghii production as well as the household decontamination prior to consumption of R. roxburghii fruits.