Ecological Safety Of Environment Research Articles

Ultra-thin FeCoNi-LDH hollow nanoflower as solid-phase microextraction coating for targeted capture of six pesticides by electrostatic adsorption

Pesticides are common pollutants that cause detriment to the ecological environmental safety and health of human due to their toxicity, volatility and bioaccumulation. In this work, an ultra-thin polymetallic layered double hydroxide (FeCoNi-LDH) with hollow nanoflower structure composite was synthesized using ZIF-67 as a self-sacrificial template, which was used as solid-phase microextraction (SPME) coating for the targeted capture pesticides, which could be combined with high-performance liquid chromatography (HPLC) to sensitive inspection pesticides in real water samples. Orthogonal experimental design (OAD) was applied to ensure the best SPME condition. Additionally, the adsorption properties were evaluated by chemical thermodynamics and kinetics. Under the optimized conditions, high adsorption capacity was obtained (117.0–21.5 mg g−1). A wide linear range (0.020–1000.0 μg L−1), low detection limit (0.008–0.172 μg L−1) and excellent reproducibility were obtained under the established method. This research provided a new strategy for designing hollow materials with multiple cations for the adsorption of anion or organic pollutants.

Morphological distribution and risk assessment of soil heavy metals in the Belly of the Three Gorges Reservoir area in Chongqing-A Case Study of Fengdu

The study of the morphological distribution and pollution risk of heavy metals in the hinterland of the Three Gorges Reservoir area in Chongqing can be used to provide data support for soil pollution prevention and control, ecological environment safety risk control and agricultural healthy development in the region. In this paper, Fengdu County, the hinterland of the Three Gorges Reservoir Area in Chongqing, was taken as the study area. The total amount and morphology of 8 heavy metal elements in the surface soil of agricultural land were analyzed and determined. The geocumulative index method was used to evaluate the pollution degree. The risk assessment coding method is used to evaluate the potential risk level. The results showed that the average contents of heavy metal elements As, Hg, Cu and Cr in the soil in the study area were relatively low. The average contents of Cd, Zn, Pb and Ni were higher than those in the Three Gorges Reservoir area. The mean value of Cd content was 1.71 times that of the background value. Cd in the soil heavy metal form is dominated by ion exchange state. The proportion of carbonate-bound state and iron-manganese bound state is relatively high. The proportion of bioavailable state was 46.36%, and the biological activity was strong. The other elements are mainly in the stable residue state. The results of the geoaccumulation index method showed that Cd was mainly mild pollution level. The other elements are mainly clean and pollution-free levels. The evaluation results of the risk assessment coding method showed that the risk of Cd contamination was the highest, and the risk of contamination of other elements was relatively low. On the whole, there is a certain degree of potential pollution risk in the soil Cd in the study area. Attention needs to be paid to the prevention and control of Cd.

Defective nitrogen doped carbon material derived from nano-ZIF-8 for enhanced in-situ H2O2 generation and tetracycline hydrochloride degradation in electro-Fenton system

Tetracycline hydrochloride (TC) accumulates in large quantities in the water environment, causing a serious threat to human health and ecological environment safety. This research focused on developing cost-effective catalysts with high 2e- selectivity for electro-Fenton (EF) technology, a green pollution treatment method. Defective nitrogen-doped porous carbon (d-NPC) was prepared using the metal-organic framework as the precursor to achieve in-situ H2O2 production and self-decomposition into high activity ·OH for degradation of TC combined with Co2+/Co3+. The d-NPC produced 172.1 mg L−1 H2O2 within 120 min, and could degrade 96.4% of TC in EF system. The self-doped defects and graphite-nitrogen in d-NPC improved the oxygen reduction performance and increased the H2O2 yield, while pyridine nitrogen could catalyze H2O2 to generate ·OH. The possible pathway of TC degradation was also proposed. In this study, defective carbon materials were prepared by ball milling, which provided a new strategy for efficient in-situ H2O2 production and the degradation of pollutants.

Adsorption kinetics of phosphorus on a calcium silicate hydrate based adsorbent

Phosphorus (P) is a fundamental element for plant and animal growth; however, an excessive amount of phosphorus can cause a threat to ecological environmental safety and human health. Therefore, this study aims to synthesize an adsorbent based on calcium silicate hydrates using mixture of polonite and calcium oxide and to determine its adsorption capacity for phosphorus ions. Additionally, pseudo-first- and pseudo-second- order kinetic models were employed to understand the adsorption process.The adsorbent based on calcium silicate hydrate was synthesized in a mixture of CaO and Polonite (CaO/SiO2 molar ratio 1.5) under hydrothermal conditions (16 h, 200 °C). It was determined that during hydrothermal treatment two crystalline (tobermorite and α-C2SH) and semicrystalline type calcium silicates hydrates were formed. Batch adsorption experiments were carried out at temperatures of 25, 35, and 45 °C in a thermostatic absorber by stirring 10 g of synthetic adsorbent in 1 l of KH2PO4 solution containing 0.2 g of P5+/L (20 mg of P5+ per gram of adsorbent) of phosphate ions. The duration of adsorption lasted up to 168 h. It was determined that adsorption capacity of synthetic adsorbent for phosphorus ions depends on the reaction duration and adsorption temperature. Synthetic adsorbent showed an extremely high adsorption capacity (>18 mg P5+/g) for phosphorus ions under all adsorption conditions. The most intensive adsorption occurred at a temperature of 35 °C as within 1 h 1 g of adsorbent adsorbed 16.6 mg of phosphorus. The equilibrium was reached after 48 h, when adsorption capacity reached 18.7 mg P5+/g. The kinetic calculations and the results of X-ray diffraction showed that chemisorption occurred during the experiments.

Influence of buffer distance on environmental geological hazard susceptibility assessment.

Previous researches seldom studied the selection of buffer distance between geological hazards (positive samples) and non-geological hazards (negative samples), and its reasonable selection plays a very important role in improving the accuracy of susceptibility zoning, protecting the environment and reducing the cost of hazard management. Based on GIS technology and random forest (RF) and frequency-ratio random forest (FR-RF) models, this study innovatively explored the influence of randomly selected non-geological hazard samples outside different buffer distances on the susceptibility evaluation results, with buffer distances of 100 m, 500 m, 1000 m and 2000 m in sequence. The results show that through the confusion matrix and ROC curve test, the accuracy of the model increases first and then decreases with the increase of buffer distance. Both RF and FR-RF models have the highest accuracy when the buffer distance is 1000 m, and the accuracy of the RF model is generally higher than that of the FR-RF model under the same buffer distance. Similar attribute values of positive samples and randomly selected negative samples or "extreme" attribute values of negative samples are the main reasons for the differences in evaluation results of different buffer distances. According to the weight analysis of causative factors, the distance from road, the distance from river and the normalized vegetation index (NDVI) are the main factors affecting the occurrence of hazards. The high and very high susceptibility areas in the study area are mainly distributed on both sides of roads and water systems, which are the key areas for hazard prevention and reduction. The HMC of RF-1000m decreased by 3.55% on average compared with other models. The results of this study improve the accuracy of geological hazard susceptibility assessment, maintain the safety of ecological environment, and provide a scientific basis for the selection of buffer distance index in local and surrounding areas in the future.

Effect of ligands regulation on Al-based metal organic frameworks for selective adsorption of xenon from spent fuel

Effective separation of inert gas such as Xe and Kr from used nuclear fuel is significant for maintaining ecological environment safety and recycling nuclear fuel. In this study, Al-CDC and Al-BDC with similar linear ligands were synthesized to reveal the influence of ligand regulation on Xe separation under different pressure conditions. The results displayed that the adsorption capacity of Al-BDC for Xe could reach 2.66 mmol g-1 under normal pressure, which is 1.11 times higher than that of Al-CDC, depending on its higher specific surface area and bigger pore volume. On the contrary, the Xe adsorption capacity of Al-CDC with the feature of narrow micropore structure and saturated C-H or oxygen-containing functional groups reached 1.44 mmol g−1 at 0.1 bar, which was 2.82 times higher than that of Al-BDC, resulting in a remarkable difference in Xe working capacity between Al-CDC (0.43 mmol g−1) and Al-BDC (0.073 mmol g−1) through dynamic breakthrough experiments. Meanwhile, the Henry’s selectivity of Al-CDC for Xe/Kr and Xe/N2 was up to 13.97 and 110.31, Compared with most porous adsorbents in previous reports, Al-CDC exhibits both high adsorption capacity and high selectivity. Innovatively, we analyzed the advantage in capacity and selectivity by the perspective of ligands, and the calculation results of the complete cell also proved that the saturated C-H group and benzene ring center on cyclohexane are the main adsorption sites of Al-CDC and Al-BDC for Xe, respectively. Therefore, a higher polar ligand in Al-CDC could lead to strong static binding energy and single cell binding energy which attribute to a high selective Xe adsorption. These results revealed the key structural characteristics for selective Xe adsorption under different pressure conditions, providing valuable suggestions for the design of separation materials from spent fuel.

Discriminative semisupervised dictionary learning method with graph embedding and pairwise constraints for crop disease image recognition

Crop diseases are serious biological disasters that affect agricultural production and ecological environment safety. Accurate detection and identification of disease types can effectively reduce the harm caused by diseases. However, there are various types of crop diseases and labeling them consumes a lot of labor and material resources. A discriminative semisupervised dictionary learning method with graph embedding and pairwise constraints (DSDL-GEPC) is proposed in this study. DSDL-GEPC adopts semisupervised dictionary learning as the baseline model, which combines the reconstruction error of all training samples and the classification error of labeled training samples. DSDL-GEPC consists of three learning terms. The graph embedding term is constructed based on dictionary atoms to obtain global geometric structural information of data samples. Using the pairwise constraint information of similar/heterogeneous images, the pairwise constraints term is constructed to enhance the dictionary's discriminability in terms of within-class similarity and between-class separability. In addition, the relaxed low-rank classification term is constructed, which introduces the ε-draggings technique and low-rank constraint on the relaxed label matrix to learn a discriminative classifier. Experiments are performed to compare the classification performance of DSDL-GEPC on the PlantVillage dataset. The results validate the effectiveness of DSDL-GEPC for crop disease image recognition.

Diffusion mechanism of solid waste product utilization pulping and fracture network grouting

China's commitment to achieving carbon neutrality by 2060 has highlighted the pressing need for effective solid waste recycling. The reinforcement of mine water hazards has led to increased production costs due to the significant consumption of slurry. This study focuses on the development of mine crack grouting sealing and reinforcement materials using mine slag powder and waste rubber particles, along with cement reinforcement and alkali slag stimulation. The impact of water-cement ratio, rubber particle content, and slag mass fraction on slurry performance is analyzed, and the optimal values for these parameters are determined. A two-phase seepage simulation using COMSOL is conducted to investigate the flow and diffusion of slurry in a fractured network rock mass. The findings indicate that a water-cement ratio of 0.7 and a slag and rubber particle mass fraction of 70% and 30% respectively result in the slurry with favorable fluidity and mechanical properties. The diffusion pattern of the slurry in the fractured rock mass is characterized by vortex-like diffusion. The stability of the fractured rock mass is influenced by both grouting time and pressure, which should be carefully considered during on-site operations. This research has significant implications for the integrated prevention and control of mine water hazards and the large-scale utilization of high-dosage solid waste, thereby ensuring production safety, ecological environment safety, and sustainable development in mining areas.

Degradation of bisphenol A by Fe-doped BiOBr enhanced UV/persulfate system: Significant role of superoxide radicals

Widely diffused pollution of endocrine disrupting chemicals (EDCs) has indeed threatened the safety of ecological environment and human health. A hydrangea-like Fe doped BiOBr (Fe-BiOBr) microsphere was synthesized and used to enhance the performance of UV/persulfate (PS) system using bisphenol A (BPA) as the targeted contaminant. The photochemical characterization of Fe-BiOBr showed that Fe doping markedly improved the separation efficiency of photoelectron and hole, and enhanced the utility rate of luminous energy of BiOBr. Degradation test demonstrated that with the assistance of Fe-BiOBr, the efficiency of UV/PS system was increased by 1.8 times, while 85.7% of BPA can be degraded within 10 min. Through scavenging experiments, sulfate radical (SO4•−), superoxide radical (O2•−), and hole were demonstrated as the dominate reactive species (RSs) in UV/Fe-BiOBr/PS system. Then, the role and mutual transformation of RSs was further clarified by radicals steady-state concentrations estimation and X-ray photoelectron spectroscopy (XPS) analysis. Based on the results, the produced O2•− can be subdivided into confined O2•− and free O2•− from the UV induced oxygen vacancy and photoelectron, respectively. Of which, SO4•− and confined O2•− were symbiotic via the redox cycle of Fe species. Significantly, only 2.6% of TOC can be simultaneously removed within 10 min treatment time, suggesting the incomplete degradation of BPA. For this, 16 organics was detected using LC-MS and the degradation route of BPA was also determined based on the intermediates analysis. Finally, the application possibility of the system was evaluated from the perspective of ecotoxicity by ECOSAR and T.E.S.T. softwares. This study investigates the dual effect of transition metal doped semiconductor on coupling system, and provides new insights into the role of O2•−.

Multifunctional Nanoparticles and Nanopesticides in Agricultural Application

The unscientific application of pesticides can easily cause a series of ecological environmental safety issues, which seriously restrict the sustainable development of modern agriculture. The great progress in nanotechnology has allowed the continuous development of plant protection strategies. The nanonization and delivery of pesticides offer many advantages, including their greater absorption and conduction by plants, improved efficacy, reduced dosage, delayed resistance, reduced residues, and protection from natural enemies and beneficial insects. In this review, we focus on the recent advances in multifunctional nanoparticles and nanopesticides. The definition of nanopesticides, the types of nanoparticles used in agriculture and their specific synergistic mechanisms are introduced, their safety is evaluated, and their future application prospects, about which the public is concerned, are examined.

Gene drive system based on CRISPR-Cas9 in mosquito control

Malaria, which is primarily transmitted by female mosquitoes, is increasing recognized as a global public health problem. Since the number of malaria cases remains high, with more than 200 million cases globally in 2019 alone, the development of new drugs and corresponding prevention and control measures are in urgent need. With the development of CRISPR/Cas9 technology in recent years, gene editing technology plays an increasingly significant role in mosquito control. A new generation of gene drive based on CRISPR/Cas9 has been applied into improving the heritability of specific genes in mosquito populations, which can be exploited to control mosquito and combat diseases transmitted by mosquito. However, this technology still faces challenges of ecological environment safety, ethical safety and technical effectiveness. This review introduces the current research status of gene drive systems for mosquito control using the CRISPR/Cas 9 system, and summarizes the current problems and solutions in this research field.

Evaluation of heavy metal contamination of soil and the health risks in four potato-producing areas

Areas polluted by heavy metals in soil may pose a major risk to human health and ecological environment safety. In this study, 89 soil samples were collected from four potato producing areas (Libo, Chishui, Panxian and Weining) in Guizhou Province, China, and the concentrations of 9 soil heavy metals were analyzed and measured. The aims of this study was to evaluate the human health risk and pollution index of heavy metals in the soil of some potato-producing areas in Guizhou Province by using the geoaccumulation index method, pollution load index method and health risk assessment method. The results revealed that Igeo<0 in Libo and Chishui, Igeo>0 in Panxian except Pb, The Igeo of As and Sb were less than 0 in Weining, and other elements were polluted to varying degrees. The pollution load index is Panxian (1.47) > Weining (1.39) > Libo (0.67), Chishui (0.67), Libo and Chishui were generally no polluted, soils in Panxian and Weining were polluted. The health risks of potatoes through food ingestion are less than 1. In terms of carcinogenesis, the risk of human in each study area through the ingestion was Cr > As > Cd. Cr and As would be produced certain carcinogenic risk to human through the dermal contact. Cr had a strong carcinogenic risk to adults through the inhalation. In terms of non-carcinogenesis, children in each study area had a strong risk under the each pathways. The risk of carcinogenesis in adults through inhalation pathway is greater than that in children, and the risk of carcinogenesis and non-carcinogenesis in children through Ingestion and dermal contact pathway is greater than adults. The results of this study suggest that attention should be paid to the remediation of heavy metals in contaminated soil to protect human health.

Effect of organophosphate esters on microbial community and proteomics in constructed wetlands and its removal mechanism

Organophosphorus esters (OPEs) may cause potential risks to human health and ecological environment safety when they enter water. In this study, A lab-scale vertical flow constructed wetlands (VFCWs) exposed to dichlorvos (DDVP) was carried out to reveal removal effect and mechanism of DDVP in VFCWs. The findings indicated CWs can remove DDVP with 94%–95% average removal efficiency in long-term operation. Besides, soluble phosphate (SRP) and total phosphorus (TP) were removed by VFCWs with 48.60%–64.10% average removal efficiency, and the addition of DDVP enhanced the effect of CWs on nitrogen removal. High-throughput sequencing demonstrated that Massiilia (2.67%–18.06%), Denitratisoma (2.07%–3.80%) and SM1A02 (2.85%–4.67%) played an important role in the removal process of DDVP in VFCWs. Proteomics of plant root showed that A0A3B6ARQ4 (increased 29.53 times) and LOC_Os11g38050.1 protein (decreased 0.001 times) responsed more sensitive to OPEs which suggested DDVP enhancesenhancing plants energy production and hydrolyase synthesis, thereby promoting it hydrolysis. Therefore, the use of VFCWs to treat organic phosphate wastewater has future prospects.

Safety assessment of fragile environment in Badain Jaran Desert and its surrounding areas based on the DPSIR model

An objective and comprehensive understanding of the safety conditions of the ecological environment is of great significance for regional social economic development and ecological environmental protection. Based on the Driving force-Pressure-State-Impact-Response (DPSIR) model, 40 indicators were selected to construct an ecological environment safety assessment system, and to evaluate ecological environment safety status for the Badain Jaran Desert and its surrounding areas (BJDCA) from 2001 to 2019. The results show that 1) From 2001 to 2019, the ecological and environmental security situation in the BJDCA showed a benign development trend. After 2010, the safety level reached the basic safety level as a medium stage out of five safety level stages. 2) The improvement of ecological and environmental security level resulted from the joint actions of socio-economic development and ecological restoration measures. In the future, the BJDCA may continue to face a series of ecological and environmental pressures brought by socio-economic developments. Therefore, we recommend an active adjustment of the development mode and proportion of the three major industries, adhering to the direction of sustainable development and ensuring the benign development of socio-economic conditions and the ecological environment. This study can provide data to support for regional ecological environment restitution and policy formulation.

Enhanced degradation of bisphenol A: Influence of optimization of removal, kinetic model studies, application of machine learning and microalgae-bacteria consortia

Bisphenol A (BPA), a typical endocrine disruptor and a contaminant of emerging concern (CECs), has detrimental impacts not only on the environment and ecosystems, but also on human health. Therefore, it is essential to investigate the degrading processes of BPA in order to diminish its persistent effects on ecological environmental safety. With this objective, the present study reports on the effectiveness of biotic/abiotic factors in optimizing BPA removal and evaluates the kinetic models of the biodegradation processes. The results showed that BPA affected chlorophyll a, superoxide dismutase (SOD) and peroxidase (POD) activities, malondialdehyde (MDA) content, and photosystem intrinsic PSII efficiency (Fv/Fm) in the microalga Chlorella pyrenoidosa, which degraded 43.0 % of BPA (8.0 mg L−1) under general experimental conditions. The bacteria consortium AEF21 could remove 55.4 % of BPA (20 mg L−1) under orthogonal test optimization (temperature was 32 °C, pH was 8.0, inoculum was 6.0 %) and the prediction of artificial neural network (ANN) of machine learning (R2 equal to 0.99 in training, test, and validation phase). The microalgae-bacteria consortia have a high removal rate of 57.5 % of BPA (20.0 mg L−1). The kinetic study revealed that the removal processes of BPA by microalgae, bacteria, and microalgae-bacteria consortia all followed the Monod's kinetic model. This work provided a new perspective to apply artificial intelligence to predict the degradation of BPA and to understand the kinetic processes of BPA biodegradation by integrated biological approaches, as well as a novel research strategy to achieve environmental CECs elimination for long-term ecosystem health.

Integrated ecosystem management and regulation strategies in the South China Sea

In order to improve the coupling degree between ecosystem and environmental security in the South China Sea Gulf and enhance the ecological environment security, the integrated management and regulation strategies of the Gulf ecosystem were proposed. Firstly, the coupling relationship between the safety culture of the South China Sea Gulf and the ecological environment safety is determined. Secondly, the grey correlation analysis method is used to calculate the correlation coefficient between the safety culture of the Gulf in the South China Sea and the ecological environment safety, and the calculation formula of the arithmetic mean value is used to deal with the correlation coefficient, so as to complete the construction of the grey correlation degree model of the ecological environment safety. On the basis of value calculation and SLOPE trend change research method, the variation of rural ecosystem service value was obtained. Finally, through the analysis of the coupling time sequence law of ecological environment security, the regulation strategy of the South China Sea Gulf ecosystem was pointed out. The proposed method has the most obvious decreasing trend in the complexity of the South China Sea Gulf, and the proposed method has a better effect, and the coupling degree of ecological environment safety is closely related.

An evaluation of the spatial rationality of provincial territory: a case study of Gansu Province.

In China, utilization and evaluation of territorial space have become national strategic issues. Evaluating the rationality of urban, ecological, and agricultural space is significant in the development of territorial space and provides a theoretical basis for the optimization of provincial territorial space. The strategic positioning of Gansu Province as a national ecological environment safety barrier is significant to the protection of the ecological environment of northwest China. This study used the entropy method to evaluate the rationality of territorial space development in 14 cities in Gansu Province in 2019, using 50 indicators of urban, ecological, and agricultural space. Results reveal that in the evaluation of these three spaces, the most important influencing indicators are water supply penetration rate, proportion of desert area, and proportion of agricultural population, respectively. In the total evaluation of territorial space rationality, the city with the highest comprehensive index is Qingyang (2.0521), followed by Zhangye (1.5635), while Lanzhou (1.1553) has the lowest evaluation. In Gansu, cities with the best territorial spatial conditions are concentrated in the east, whereas those with poor territorial spatial environmental security are located in central Gansu and the Hexi Corridor. Collectively, these findings suggest that the equity and rationality of urban, ecological, and agricultural space in territorial space should be considered in territorial space planning strategies. The balance and harmony of these three spaces play a positive role in the sustainable development of the economy, society, and the environment in urban areas.

Lightweight ceramsite made of recycled waste coal gangue & municipal sludge: Particular heavy metals, physical performance and human health

Large amounts of coal gangue and municipal sludge are generated from coal mining and municipal sewage. Some scholars have studied their use in ceramics, concrete, land reclamation and so on. However, in current study, heavy metals in coal gangue and municipal sludge in utilization have not been safely controlled, and there are potential risks to the ecological environment and human health. Therefore, this study systematically investigated the basic physical and chemical properties of coal gangue and municipal sludge samples, the ecological environment safety risk of heavy metals and other harmful substances (soluble phosphorus and fluorine). The results showed that the main compositions of coal gangue and municipal sludge samples were cristobalite, hematite and anorthite, which can be used as raw material for ceramsite preparation. The characteristic heavy metals in coal gangue and municipal sludge were As, Cd, Cu, Ni and Zn, which had certain environmental risks. When the optimum proportion of coal gangue: sludge = 70: 30, adding clay and blowing agent as auxiliary materials to make ceramsite, its properties, including bulk density, cylinder pressure strength and other physical properties, meet the Chinese standard “light aggregate and its test method” (GB/T 17431). The heavy metal environment and human health assessment model of the product was constructed, in which the risk assessment results are, that the content of characteristic heavy metals in ceramsite was significantly reduced, and this content conformed to the requirements of heavy metals in the Chinese standard “technical specification of cement kiln cooperative disposal of solid waste” (GB/T 30760), riskless to the human body and external environment. The compressive strength of the two kinds of ceramsite concrete can reach LC35, and the density grade was 1400–1650 N/m3, which meets the requirements of Chinese standard “technical specification for lightweight aggregate concrete” (JGJ 51). All the properties of this product meet the corresponding standards and there was no risk to the external environment, to provide theoretical guidance for the harmless and resource utilization of urban sludge and coal gangue.

Human carcinogenic risk analysis and utilization of shale gas water-based drilling cuttings in road materials.

Water-based drilling cuttings (WDC) generated during shale gas development will endanger human health and ecological security. The modern analytical techniques are used to analyze the organic pollutants in WDC, and the human health and ecological security risks of harmful pollutants in WDC under specific scenarios are evaluated. The results showed that the content of organic pollutants in WDC was evaluated by human health and safety risk assessment. The comprehensive carcinogenic risks of all exposure pathways of single pollutant benzo(a)anthracene, benzo(a)pyrene, benzo(k)fluoranthene, and indeno(1,2,3-cd)pyrene were acceptable. However, the cumulative carcinogenic risk of exposure to dibenzo(a,h)anthracene particles via skin exposure was not acceptable. It was considered that only dibenzo(a,h)anthracene had carcinogenic effect, and the risk control limit of dibenzo(a,h)anthracene in WDC was 1.8700 mg/kg by calculation. As well as, the “WDC-cement” gel composite structure was deeply analyzed, and the physical and chemical properties and mechanism of organic pollutants in cement solidified WDC were analyzed, which provided theoretical support for the study of WDC pavement cushion formula. Based on the above conclusions and combined with the actual site, by studying and adjusting the formula of WDC pavement cushion, the WDC pavement cushion was finally designed by 6% cement + 50% WDC + 44% crushed stone. The 7d unconfined compressive strength met the requirements of the Chinese standard “Technical Guidelines for Construction of Highway Roadbases” (JTG/T F20-2015). Also, the process route of WDC as road cushion product was sampled and analyzed. In addition, the leaching concentration of main pollutants all met the relevant standards of China. Therefore, this study can provide a favorable way for the efficient, safe, and environmentally friendly utilization of WDC, and ensure the ecological environment safety and human health safety of WDC in resource utilization.

Pozzolanic activity and environmental risk assessment of water-based drilling cuttings of shale gas

• The pozzolanic activity of WDC was comprehensively studied. • A systematic study of human carcinogenic risk and ecological security risk assessment were carried out. • The risk control values of heavy metals were presented In order to evaluate the application potential of water-based drilling cuttings (WDC) as cementitious materials for building material admixtures, the physical and chemical properties of WDC were studied, and the environmental risk and human health risk of heavy metals in WDC were also systematically studied. The results showed that the particle pitch diameter is 26.70 µm, mineral types of WDC are mainly limestone, calcium hydroxide and quartz. The 28-day compressive strength of WDC is 27.6 MPa. The strength activity index of WDC cement mortar is 58.3 %, and the amorphous phase content is 23 %. At 80 °C, the weight loss rate and bound water content of “ WDC-CaO-H 2 O ” hydrate were 5 % and 0.13, respectively. It is found that WDC has certain pozzolanic activity, can not only participate in the secondary reaction of the system as active mineral admixtures, but also reduce harmful holes in the system by filling compaction. According to the calculation and analysis, only Hg reached moderate pollution in WDC, As and Cr had carcinogenic risks to human health, so Hg, As and Cr were used as characteristic heavy metal pollutants in WDC. As well as, under the analysis results of characteristic heavy metals and the limits of relevant standards, the risk control values of heavy metals in different exposure scenarios were obtained. The expected existence of arsenic ions, chromium ions and mercury ions in XPS spectra and their corresponding binding energy and orbital state were analyzed. After analysis and fitting, these values are basically consistent with the reference values cited in the document, and the resource utilization direction and environmental safety control measures of WDC were proposed. The above research results will further promote the basic technical support of shale gas WDC resource utilization, and ensure the ecological environment safety and human health safety in the process of resource utilization.