Source-specific ecological and health risks of polycyclic aromatic hydrocarbons in the adjacent coastal area of the Yellow River Estuary, China.

Industrialization and urbanization have led to increasing levels of PAH pollution in highly urbanized estuaries and their adjacent coastal areas globally. This study focused on the adjacent coastal area of the Yellow River Estuary (YRE) and collected surface seawater, surface sediment, and clams Ruditapes philippinarum and Mactra veneriformis at four sites (S1 to S4) in May, August, and October 2021 to analyze the source-specific ecological and health risks and bioeffects. The findings revealed that the main sources of PAHs were traffic emission (25.2% to 28.5%), petroleum sources (23.3% to 29.5%), coal combustion (24.7% to 27.5%), and biomass combustion (19.8% to 20.7%). Further, the PMF-RQ and PMF-ILCR analyses indicated that traffic emission was the primary contributor to ecological risks in seawater and health risks in both clam species, while coal combustion was the major contributor in sediment. Taken together, it is recommended to implement control strategies for PAH pollution following the priority order: traffic > coal > petroleum > biomass, to reduce the content and risk of PAHs in the YRE.

Characterizing VOCs emissions of coal chemical enterprise in China: a case study in five coal chemical enterprises.

Coal chemical-induced climate change has become a global concern. However, the dearth of comprehensive case studies and fundamental data has obstructed the accurate quantification of volatile organic compounds (VOCs) emissions. This has failed to equip coal chemical industries with the necessary guidelines to implement effective emission reduction strategies. In response to this, the present study meticulously examined and contrasted the VOCs emissions from five distinct coal chemical enterprises in China. This was achieved through the application of life cycle assessment (LCA), a tool used to discern the primary factors influencing VOCs emissions and to identify potential avenues for VOCs emissions reduction. The analysis revealed that BT exhibited the highest emission intensity (5.58E-04 tons/ton), followed by ED (4.89E-04 tons/ton), YL (4.23E-04 tons/ton), XJ (2.94E-04 tons/ton), and SM (1.74E-04 tons/ton). Among these enterprises, coal-to-olefins enterprises predominantly discharged VOCs via sewage treatment (average 69.12%), while coal-to-methanol enterprises primarily emitted VOCs during circulating water cooling (40.02%). In coal-to-oil enterprises, storage and blending emerged as the principal source of VOCs emissions (56.83%). As a result, this study advocates that coal chemical enterprises concentrate on curbing VOCs emissions from highly concentrated wastewater, regulating the concentration of purgeable organic carbon in circulating water cooling systems, and instituting effective treatment methods for methanol storage tank emissions. These findings proffer invaluable insights for devising VOCs control measures in regions affected by intensive coal chemical production.

Examining the residual radiological footprint of a former colliery: An industrial nuclear archaeology investigation.

Nuclear industrial archaeology utilises radiation mapping and characterisation technologies to gain an insight into the radiological footprint of industrial heritage sites. Increased concentrations of naturally occurring radioactive materials at legacy mine sites are the result of elemental enrichment during coal mining and subsequent combustion. Public safety is of concern around these sites, and therefore, an increased understanding of their associated hazard is essential. Using coincident laser scanning and gamma detection technologies, this study sought to assess the radiological legacy of a coal mine located in Bristol, UK. From this, we can increase our understanding of the residual footprints associated with the local coal mining industry. Samples taken from inside the site were characterised using high resolution gamma spectrometry, wherein the radionuclide content and activities of samples were then quantified. An area of elevated low-level radioactivity was observed at and around buildings believed to belong to the colliery, while Th, U, and K are confirmed at the site from photopeak's of daughter radionuclides. Activities of the radionuclides K-40, U-238, and Th-232 were further quantified during subsequent laboratory analysis. Results highlight an enrichment of naturally occurring radionuclides when compared with global averages for unburned coal. Employing these techniques at further legacy sites would enable an increased understanding of the lasting traces of the coal mining industry, with a focus on NORM enrichment in residual fly ash.

Preparation and characterization of ZSM-5 molecular sieve using coal gangue as a raw material via solvent-free method: Adsorption performance tests for heavy metal ions and methylene blue.

Coal gangue is a kind of solid waste produced in the process of coal mining and washing. Its silicon aluminum silicon aluminum oxide content is high, respectively, which are suitable for resource utilization as raw materials for Si-Al molecular sieving. In this paper, a novel, simple, low-cost, and environmentally friendly process was carried out to prepare ZSM-5 zeolite by solvent free method after calcination, acid leaching, and alkali melting. The obtained samples were characterized by Energy Dispersive Spectrometer (EDS), Inductively Coupled Plasma (ICP), Thermo-gravimetry Analysis (TG), X-ray Photoelectron Spectroscopy (XPS), Fourier Transform Infrared Spectrometer (FTIR) X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM) and N2 adsorption isotherm. The characteristics of the raw materials and the adsorption mechanism of the prepared samples were characterized. Through a series of pretreatment such as calcined acid leaching and alkali melting of the raw materials, the silicon-aluminum ratio of the sample reaches 1.749, and the maximum specific surface area of the sample can reach 252.59 m2/g. The obtained samples were used to adsorb heavy metal ions and methylene blue solution, and the removal rate of lead ions and methylene blue solution was more than 95%. The theoretical maximum adsorption capacity of Pb ion, methylene blue solution and copper ion can reach 232.56 mg/g and 118.34 mg/g. The adsorption process is mainly chemical adsorption. The product could be suitable for removing both heavy metal ions and cationic dyes from the wastewater and had broad application prospects.

Technical-economic and environmental protection performance evaluation of a novel hybrid solar-nuclear thermally coupled power and desalination plant.

Clean energy complementary system can reduce environmental pollution effectively and is considered as a future energy development direction. In this paper, an innovative solar-nuclear thermally coupled power and desalination plant for electricity and freshwater productions is proposed. As solar power and nuclear power are combined, this multi-energy system is a clean energy system and basically has no emissions of soot, sulfur oxides, carbon dioxide, and nitrogen oxides. The operating behavior assessment results of the multi-energy system show that the power generation and freshwater production systems can operate synergistically. The electric power and corresponding efficiency of the multi-energy system are 290.7 MW and 38.2%, in which the solar proportion is about 38.1%. The daily freshwater production of the multi-energy system is 3761.3 t. The economic assessment results reveal that the levelized costs of electricity and freshwater of the multi-energy system are 0.361 yuan/(kWh) and 1.645 yuan/t. The environmental protection analysis results show that in contrast with a coal-fired system, the annual emission reductions of soot, sulfur oxides, carbon dioxide, and nitrogen oxides of the multi-energy system are 7350.94 t, 12,634.42 t, 513,034.14 t, and 11,945.28 t, revealing a significant environmental protection performance.

Coal fly ash application as an eco-friendly approach for modulating the growth, yield, and biochemical constituents of Withania somnifera L. plants.

The solid waste known as fly ash, which is produced when coal is burned in thermal power plants, is sustainably used in agriculture. It is an excellent soil supplement for plant growth and development since it contains some desired nutrients (macro and micro), as well as being porous. The present study was done to evaluate the effect of different fly ash levels on Withania somnifera. The present study aimed to assess the impact of various fly ash (FA) concentrations on growth, yield, photosynthetic pigments, biochemical parameters, and cell viability of W. somnifera. The results showed that FA enhanced physical and chemical properties of soil like pH, electric conductivity, porosity, water-holding capacity, and nutrients. The low doses of FA-amended soil (15%) significantly increased the shoot length (36%), root length (24.5%), fresh weight of shoots and roots (107.8 and 50.6%), dry weight of shoots and roots (61.9 and 47.1%), number of fruits (70.4%), carotenoid (43%), total chlorophyll (44.3%), relative water content (109.3%), protein content (20.4%), proline content (110.3%), total phenols (116.1%), nitrogen (20.3%), phosphorus (16.9%), and potassium (26.4%). On the other hand, the higher doses, i.e., 25% of fly ash showed a negative effect on all the above parameters and induced oxidative stress by increasing lipid peroxidation (33.1%) and hydrogen peroxide (102.0%) and improving the activities of antioxidant enzymes and osmolytes. Compared to the control plants, the plants growing in soil enriched with 15 and 25% fly ash had larger stomata pores when examined using a scanning electron microscope. In addition, according to a confocal microscopic analysis of the roots of W. somnifera, higher fly ash concentrations caused membrane damage, as evidenced by an increase in the number of stained nuclei. Moreover, several functional groups and peaks of the biomolecules represented in the control and 15% of fly ash were alcohols, phenols, allenes, ketenes, isocynates, and hydrocarbons. Gas chromatography-mass spectrometry analysis of the methanol extract of W. somnifera leaves cultivated in soil amended with 15% fly ash shows the presence of 47 bioactive compounds. The most abundant compounds in the methanol extract were cis-9-hexadecenal (22.33%), n-hexadecanoic acid (9.68%), cinnamic acid (6.37%), glycidyl oleate (3.88%), nonanoic acid (3.48%), and pyranone (3.57%). The lower concentrations of FA (15%) can be used to enhance plant growth and lower the accumulation of FA that results in environmental pollution.

Research on the evolution law of hot spots in the field of coal seam hydraulic fracturing based on bibliometric analysis: review from a new scientific perspective.

As an unconventional natural gas, the calorific value of coal seam gas (CSG) is equivalent to that of natural gas. It is a high-quality, clean, and efficient green low-carbon energy source. Coal seam hydraulic fracturing is an important permeability enhancement measure in the process of CSG drainage. In order to further understand the overall research progress in the field of coal seam hydraulic fracturing, the Web of Science (WOS) database is used as a sample source, and the bibliometric analysis of the literature is carried out by CiteSpace software. The visual knowledge maps of the number of publications, the research countries, institutions, and keyword clustering are drawn. The research shows that it has gone through two stages of slow development and rapid growth in terms of time distribution. In terms of cooperation networks, the main active countries include China, the USA, Australia, Russia, and Canada, composed of China University of Mining and Technology, Chongqing University, Henan Polytechnic University, and China University of Petroleum as the core research institutions. Taking keywords as the theme, the coal seam hydraulic fracturing research field mainly involves high-frequency keywords such as hydraulic fracturing, permeability, model, and numerical simulation. The hotspot evolution law and frontier development trend of keywords with time are analyzed and obtained. On this basis, from a new perspective, the "scientific research landscape map" in the field of coal seam hydraulic fracturing is outlined, in order to provide a scientific reference for the research in this field.

Regional Sources and Sinks of Atmospheric Particulate Selenium in the United States Based on Seasonality Profiles.

Selenium (Se) is an essential nutrient for humans and enters our food chain through bioavailable Se in soil. Atmospheric deposition is a major source of Se to soils, driving the need to investigate the sources and sinks of atmospheric Se. Here, we used Se concentrations from PM2.5 data at 82 sites from 1988 to 2010 from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network in the US to identify the sources and sinks of particulate Se. We identified 6 distinct seasonal profiles of atmospheric Se, grouped by geographical location: West, Southwest, Midwest, Southeast, Northeast, and North Northeast. Across most of the regions, coal combustion is the largest Se source, with a terrestrial source dominating in the West. We also found evidence for gas-to-particle partitioning in the wintertime in the Northeast. Wet deposition is an important sink of particulate Se, as determined by Se/PM2.5 ratios. The Se concentrations from the IMPROVE network compare well to modeled output from a global chemistry-climate model, SOCOL-AER, except in the Southeast US. Our analysis constrains the sources and sinks of atmospheric Se, thereby improving the predictions of Se distribution under climate change.

Vertical distribution, environmental occurrence, and risk assessment of organic pollutants in lacustrine sediments in southeast China.

To clarify the impact of human activities on the natural environment, as well as the current ecological risks to the environment surrounding Zhushan Bay in Taihu Lake, the characteristics of deposited organic materials, including elements and 16 polycyclic aromatic hydrocarbons (∑16PAHs), in a sediment core from Taihu Lake were determined. The nitrogen (N), carbon (C), hydrogen (H), and sulfur (S) contents ranged from 0.08 to 0.3%, 0.83 to 3.6%, 0.63 to 1.12%, and 0.02 to 0.24%, respectively. The most abundant element in the core was C followed by H, S, and N, while elemental C and the C/H ratio displayed a decreasing trend with depth. The ∑16PAH concentration was in the range of 1807.48-4674.83 ng g-1, showing a downward trend with depth, with some fluctuations. Three-ring PAHs dominated in surface sediment, while 5-ring PAHs dominated at a depth of 55-93 cm. Six-ring PAHs appeared in the 1830s and gradually increased over time before slowly decreasing from 2005 onward due to the establishment of environmental protection measures. The ratio of PAH monomers indicated that PAHs in samples from a depth of 0 to 55 cm were mainly derived from the combustion of liquid fossil fuels, while the PAHs in the deeper samples mainly originated from petroleum. The results of a principal component analysis (PCA) showed that the PAHs in the sediment core of Taihu Lake were mainly derived from the combustion of fossil fuels, such as diesel, petroleum, gasoline, and coal. The contributions of biomass combustion, liquid fossil fuel combustion, coal combustion, and unknown source were 8.99%, 52.68%, 1.65%, and 36.68%, respectively. The results of a toxicity analysis indicated that most of the PAH monomers had little impact on the ecology, and the annual increase of a small number of monomers might have toxic effects on the biological community, resulting in a serious ecological risks, that requires the imposition of control measures.

Environmental Impacts of Coal Combustion Residuals: Current Understanding and Future Perspectives.

On-site solid-waste impoundments, landfills, and receiving water bodies have served as long-term disposal sites for coal combustion residuals (CCRs) across the United States for decades and collectively contain billions of tons of CCR material. CCR components include fine particulate material, minerals, and trace elements such as mercury, arsenic, selenium, lead, etc., which can have deleterious effects on ecosystem functioning and public health. Effects on communities can occur through consumption of drinking water, fish, and other aquatic organisms. The structural failure of impoundments, water infiltration, leakage from impoundments due to poor construction and monitoring, and CCR effluent discharges to water bodies have in the past resulted in harmful environmental impacts. Moreover, the risks posed by CCRs are present to this day, as coal continues to account for 11% of the energy production in the United States. In this Critical Review, the legacy of CCR disposal and the concomitant risks posed to public health and ecosystems are assessed. The resiliency of CCR disposal sites in the context of increased frequency and intensity of storm events and other hazards, such as floods and earthquakes, is also evaluated. We discuss the current state of knowledge on the environmental fate of CCR-derived elements, as well as advances in and limitations of analytical tools, which can improve the current understanding of CCR environmental impacts in order to mitigate the associated risks. An assessment of the 2015 Coal Ash Final Rule is also presented, along with needs to improve monitoring of CCR disposal sites and regulatory enforcement.

Application of Pb Isotopes and REY Patterns in Tracing Heavy Metals in Farmland Soils from the Upper-Middle Area of Yangtze River.

Farmland heavy metal pollution-caused by both human activity and natural processes-is a major global issue. In the current study, principal component analysis (PCA), cluster analysis (CA), rare earth elements and yttrium (REY) analysis, and isotope fingerprinting were combined to identify sources of heavy metal pollution in soil from different farmland types in the upper-middle area of the Yangtze River. The concentrations of Zn and Cu were found to be higher in the vegetable base and tea plantation soil compared with their concentrations in the orangery soil. On the other hand, greater accumulation of Cd and Pb was observed in the orangery soil versus the vegetable base and tea plantation soils. Influenced by the type of bedrock, REY was significantly enriched in the orangery soil and depleted in the vegetable base soil, as compared with the tea plantation soil. The Pb isotopic compositions of the tea plantation (1.173-1.193 for 206Pb/207Pb and 2.070-2.110 for 208Pb/206Pb) and vegetable base (1.181-1.217 for 206Pb/207Pb and 2.052-2.116 for 208Pb/206Pb) soils were comparable to those of coal combustion soil. The compositions of 206Pb/207Pb (1.149-1.170) and 208Pb/206Pb (2.121-2.143) in the orangery soil fell between those observed in soils obtained from coal combustion and ore smelting sites. Using the IsoSource model, the atmospheric Pb contributions of the vegetable base, tea plantation, and orangery soils were calculated to be 66.6%, 90.1%, and 82.0%, respectively, and the bedrock contributions of Pb were calculated to be 33.3%, 9.90%, and 18.1%, respectively. Based on the PCA, CA, and REY results, as well as the Pb isotope model, it appears that heavy metals in the orangery soil may be derived from atmospheric deposition and bedrock weathering, while heavy metals in the vegetable base and tea plantation soils may be derived from mining and the use of fertilizer.

Characteristics and health risk assessment of heavy metal pollution in atmospheric particulate matter in different regions of the Yellow River Delta in China.

To understand the characteristics, temporal and spatial variation, and health risks of atmospheric heavy metal pollution in different areas of the YRD (Yellow River Delta), atmospheric particles samples were collected in the YRD in China during 2016-2017. A total of 10 monitoring points were chosen in different areas (industrial parks, main urban areas, and rural areas) in the YRD, heavy metals were monitored using atomic fluorescence spectrometry and graphite furnace atomic absorption spectrometry. The results showed that TSP (total suspended particulate), PM10 (particulate matter with an aerodynamic diameter less than 10 µm), and PM2.5 (particulate matter with an aerodynamic diameter less than 2.5 µm) contents were higher in the Kenli EDZ (economic development zone) and Kenli urban areas than those in other points. The concentration range of heavy metals in atmospheric samples at 10 points was different, with a difference of five orders of magnitude, of which the content of copper (Cu) was the highest, with the highest concentration of 4.375 µg/m3, and the content of particulate mercury (Hg) was the lowest, with the minimum concentration of 0.00001 µg/m3. Among the nine heavy metals, the contents of cadmium (Cd), lead (Pb), and Hg were higher in winter than in summer, and chromium (Cr), nickel (Ni), Cu, and manganese (Mn) were higher in summer than in winter. In addition to Hg, the contents of the other eight heavy metals in particulate matter showed a trend that urban areas and EDZs had higher concentrations than cities and towns and nature reserves, which can be attributed to industrial activities and coal-fired fuel emissions. Health risk assessment was carried out for adults and children, respectively, and the results showed that carcinogens have no obvious carcinogenic risk, but As and Cr have major potential carcinogenic risk. Among the noncarcinogenic substances, Mn has the greatest noncarcinogenic risk, and urban areas and economic development zones have the greatest risk. This study investigated the characteristics and health risk assessment of atmospheric heavy metal pollution in different areas in the YRD to supplement the research contents of atmospheric particulate heavy metals in the YRD in domestics and overseas. It is also critical to study the pollution and migration of heavy metals in China.

Impacts of carbon markets and subsidies on carbon capture and storage retrofitting of existing coal-fired units in China.

Carbon capture and storage (CCS) is a feasible technology option to reduce carbon emission in the power industry. However, the high cost of CCS deployment in power plants precludes its large-scale application. Carbon markets may act as an incentive for CCS, but the impact of auction and quota allocation mechanisms in carbon markets on CCS is unclear. In order to investigate the roles of the auction and quota allocation mechanism on the CCS retrofitting in coal-fired units, the life-cycle cost method was used to evaluate the CCS retrofitting cost of China's coal-fired units in the carbon market after supplementing the existing database. The impact of subsidies on stimulating CCS retrofitting was jointly considered. The results show that most units have a CCS retrofit Levelized additional cost of electricity (Lacoe) of $25.24/MWh to $64.57/MWh, making the CCS retrofitting burdensome, even for ultra-supercritical unit that has a low cost. The combination of grandfathering quota allocation mechanism and subsidy will effectively promote CCS retrofitting of coal-fired units, especially when the auction ratio is 30%-40%, about 400-540 GW units will be retrofitted under the carbon market using grandfathering and 12.05$/MWh-22.77$/MWh subsidies. Additionally, there are significant differences among provinces in terms of the lifetime costs of the CCS retrofitting of coal-fired units. Xinjiang, Guangdong, and Jiangsu, with retrofitting potentials of respectively 20.68 GW, 10.58 GW-43.00 GW and 15.00 GW-52.27 GW are best suited for the CCS retrofitting of coal-fired units.

Chemical association of copper and selenium in coals of Sindh by time saving single step strategy and their impact on groundwater.

The aim of the present study is to estimate the different chemical fractionations of copper (Cu) and selenium (Se) in coal samples of different coal mining areas. The Cu and Se bound to various chemical fractions of coal collected from two mining fields of Sindh, Pakistan, have been determined by BCR sequential extraction scheme (BCR-SES). The long duration of the BCR sequential scheme (51 h) was reduced by a time-saving shaking device (ultrasonic bath) termed as ultrasonic-assisted extraction (USE) depending on the same operating conditions and extracting solutions used for BCR sequential extraction scheme. The both trace elements were determined in aquifer water, sampled from different depth of both coal mining fields. In addition, the groundwater of dug well in the vicinity of coal mining areas were also analyzed for Cu and Se using reported extraction methodologies. The partitioning of Cu and Se bound with different chemical fractions of coal was successfully made by proposed USE, within 2 h as compared to long duration of BCR-SES (51 h). The Cu and Se concentrations in acid-soluble fractions of coal samples were > 10%, enhanced by USE extraction procedure than those values gained via BCR-SES (p < 0.01). About 67 to 69% of Cu were found in the first three fractions, whereas their remaining amount corresponding to 31 to 33%, respectively bound with crystalline/residual fraction, while up to 66.1 to 71.1% of total Se contents extracted in three extractable phases, followed up to 28.9 to 33.8% of it was bound with residual phase. The concentrations of Cu and Se in groundwater of different aquifers were found in decreasing order as AQ1 > AQII > AQIII; the same trend was observed for two aquifers of Lakhra coal mining, whereas the groundwater samples have two to three folds higher levels of Se than WHO limit. The Cu levels in water samples were significantly lower than the recommended limit of WHO for drinking water (p < 0.01).

Basic characteristics of magnesium-coal slag solid waste backfill material: Part I. preliminary study on flow, mechanics, hydration and leaching characteristics.

The environmental damage caused by surface subsidence and coal-based solid waste (CBSW) is a common problem in the process of coal mining. Backfill mining can control the mining-induced subsidence and solve the problem of bulk solid waste storage. In the present work, a magnesium-coal slag solid waste backfill material (MCB) with modified magnesium slag (MS) as binder and CBSW (fly ash (FA), flue gas desulfurization gypsum (FDG) and coal gasification slag (CGS)) as supplementary cementitious material/aggregate was proposed to meet the needs of coal mining in Northern Shaanxi, China, to realize the comprehensive treatment of goaf and CBSW. The results show that: (1) The rheological curve of the fresh MCB slurry is highly consistent with the Herschel-Bulkley (H-B) model, and its fluidity meets the basic requirements of mine backfill pumping. With the addition of FDG and MS, the yield stress, apparent viscosity and thixotropy of MCB slurry increase, while the pseudoplastic index and slump decrease. (2) The strength of MCB develops slowly in the early stage (0∼14 days) and increases rapidly in the later stage (14∼90 days). Except for the ratio of M20F1 and FDG = 0%, the strength of samples at other ratios (at 28 days) is between 6.06∼11.68 MPa, which meets the strength requirement of 6 MPa for coal mine backfill. The addition of MS and appropriate amount of FDG is beneficial to the development of strength. In contrast, MS exhibits a significant improvement in early strength, and FDG has a significant improvement in late-age strength. (3) Corresponding to the compressive strength, the hydration products C-S(A)-H and AFt of MCB are less in the early stage and greatly increased in the later stage. The active substance in FA/CGS will undergo pozzolanic reaction with the MS hydration product CH. The addition of FDG and MS can promote the reaction and increase the amount of hydration product, but in contrast, the promotion effect of FDG is more significant. (4) The amount of heavy metal leaching of MCB meets the requirements of national standards. The hardened MCB has a solidification/stabilization effect on heavy metal elements, which can significantly reduce the amount of heavy metal leaching. The results imply that MCB is a safe, reliable, and eco-friendly solid waste backfill material, and its application is conducive to the coordinated development of coal resource mining and environmental protection.

An improved hybrid model on source-risk of polycyclic aromatic hydrocarbon in soils of the Yangtze River Delta urban agglomeration.

The source, exposure and risks of polycyclic aromatic hydrocarbons (PAHs) in soil environments are of great importance to evaluate soil quality. However, understanding the risks of specific sources of PAHs in soils remains poorly understood. In this study, we determined the source, exposure and risks of PAHs in the Yangtze River Delta urban agglomeration. The source analysis receptor model combined with land use types significantly increased the identification of pollution sources and improved the prediction accuracy of PAH concentrations. There is a strong correlation between the measured and predicted values of high ring PAH. The correlations of BbF, InP and Pyr are 0.947, 0.896 and 0.906 respectively, which is significantly higher than the unmodified model. By combining the ecological risk assessment and health risk assessment models of PAHs, we established an improved mixed source-risk model. The PAHs in urban soils had the highest ecological risk and health risk, with risk probabilities of 56.3 % and 28.2 %, respectively. The average contamination severity index values of PAHs caused by oil combustion sources, coal combustion sources, coking furnace sources, and fuel (biomass, petroleum, and diesel) combustion sources were 0.13, 0.10, 0.16 and 0.17, respectively. The average noncarcinogenic risks of PAHs from oil combustion sources, coal combustion sources, coking furnace sources and biomass, petroleum volatilization and diesel combustion sources to children were 0.12, 0.11, 0.08 and 0.13, respectively. Approximately half of the PAH pollution risk in forestland and grassland soil were associated with the combustion of petroleum fossil fuels. This study quantitatively analyzed the contribution of different PAHs pollution sources in different land types of soils, further calculated the risks of each pollution source to the ecological environment and human health, and proposed corresponding treatment measures, which provided scientific and systematic methods and technologies for soil pollution management in other regions of the world.

Spatio-temporal association mining of intercity PM2.5 pollution: Hubei Province in China as an example.

The complex interaction between emissions, meteorology, and atmospheric chemistry makes accurate predictions of particulate pollution difficult. Advanced data mining techniques can reveal potential laws, providing new possibilities for understanding the evolution and causes of air pollution. Based on the Granger method and block modeling analysis, this paper explored the intercity spillover effects of hourly PM2.5 in Hubei Province, China, to determine the specific role (i.e., overflow, limited overflow, bilateral, inflow, and limited inflow) of each city on regional pollution formation. Furthermore, a dynamic Apriori algorithm considering time-lag effects was used to mine the spatio-temporal associations of extreme PM2.5 pollution events among different cities. Results suggest that the northern and central cities with high-level PM2.5 concentration in Hubei have a significant spillover effect, whereas the eastern and southern cities generally play a role as the sink of pollutants. Based on the association rules of extreme PM2.5 pollution, four main pollutant transport channels were excavated and well matched with the trajectories extracted by the atmospheric model. This paper provides new insights for exploring the interaction of intercity particulate pollution, which is a supplement and cross-validation of the model results.

Does exposure to weathered coal ash with an enhanced content of uranium-series radionuclides affect flora? Changes in the physiological indicators of five referent plant species.

Coal ash deposited in open landfills is a potential source of environmental pollutants due to the contained toxic element content. The weathered coal ash used in this study additionally contains enhanced activity concentrations of 238U series radionuclides. This study aimed to determine the physiological effects of enhanced ionizing radiation and toxic elements on five plant species (smilo grass, sticky fleabane, blackberry, mastic and pine tree) inhabiting the coal ash disposal site. Among the potentially toxic measured elements, contents of Sb, As and especially V significantly exceeded their respective levels at the control site, as well as the content of 238U and its progenies. Significant changes in photosynthetic pigments were recorded following chronic exposure to the plants growing on the coal ash site. Different responses were also observed in the plant species regarding the activity of catalase and glutathione-S-transferase (GST). The level of lipid peroxidation markedly increased in plants from the disposal site, except in blackberry, wherein GST activity was the strongest, indicating an important role of that enzyme in the adaptation to coal ash pollutants. The results of this study suggest that the modulation of the studied biochemical parameters in plants growing on coal ash is primarily species-dependent.

Immobilization of Pb and Zn in Contaminated Soil Using Alumina-Silica Nano-Amendments Synthesized from Coal Fly Ash.

To apply coal fly ash to the remediation of heavy-metal-contaminated soil, an alumina-silica nano-amendment (ASNA) was synthesized from coal fly ash and was used for the immobilization of lead and zinc in contaminated soil. The investigation on the synthesis of the ASNA shows that the ASNA can be obtained under a roasting temperature of 700 °C, a ratio of alkali to coal fly ash of 1.2:1, and a molar ratio of silicon to aluminum of 1:1. The ASNA could increase the soil pH and cation exchange capacity (CEC) and decrease the bioavailability of Pb and Zn. When the ASNA addition increased from 0 to 2%, the bioavailability (extracted by CaCl2) of Pb and Zn decreased by 47% and 72%, respectively. Moreover, the addition of the ASNA facilitated the transformation of Pb from a reducible fraction to oxidizable and residual fractions and Zn from an exchangeable fraction to a residual fraction. The correlation analysis and cluster analysis verify that the ASNA modulates the chemical speciation of heavy metals by increasing the soil's CEC and pH, thereby immobilizing heavy metals. It is expected that this study can provide a new method for the remediation of Pb- and Zn-contaminated soil.

Potentially hazardous metals in the sediment of a subtropical bay in South China: Spatial variability, contamination assessment and source apportionment.

Potentially hazardous metals (PHMs) in the coastal environment have become a great concern due to their easy bioaccumulation, poor biodegradability and high toxicity. Surface sediment samples were collected in a subtropical bay in South China to analyse the spatial variations, contamination level and potential sources of PHMs. The results indicated that the order of average contents of PHMs in Qinzhou Bay sediment was Zn > Pb > Cr > Cu > As > Hg > Cd. The most important potential ecological risk factor was Hg pollution in the Qinzhou Bay sediments. The positive matrix factorization (PMF) model results indicated that Cu, Pb, Zn, Cd and Cr mainly originated from natural sources while Hg and As were related to coal fired industrial inputs and petroleum production activities. The results could provide a basis for marine management to formulate relevant pollution prevention and control measures.