An exploration of an integrated stochastic-fuzzy pollution assessment for heavy metals in urban topsoil based on metal enrichment and bioaccessibility

Revealing the Sources of Cadmium in Rice Plants under Pot and Field Conditions from Its Isotopic Fractionation

The highly excessive uptake of cadmium (Cd) by rice plants is well known, but the transfer pathway and mechanism of Cd in the paddy system remain poorly understood. Herein, pot experiments and field investigation were systematically carried out for the first time to assess the phytoavailability of Cd and fingerprint its transfer pathway in the paddy system under different treatments (slaked lime and biochar amendments), with the aid of a pioneering Cd isotopic technique. Results unveiled that no obvious differences were displayed in the δ114/110Cd of Ca(NO3)2-extractable and acid-soluble fractions among different treatments in pot experiments, while the δ114/110Cd of the water-soluble fraction varied considerably from -0.88 to -0.27%, similar to those observed in whole rice plant [Δ114/110Cdplant-water ≈ 0 (-0.06 to -0.03%)]. It indicates that the water-soluble fraction is likely the main source of phytoavailable Cd, which further contributes to its bioaccumulation in paddy systems. However, Δ114/110Cdplant-water found in field conditions (-0.39 ± 0.05%) was quite different from those observed in pot experiments, mostly owing to additional contribution derived from atmospheric deposition. All these findings demonstrate that the precise Cd isotopic compositions can provide robust and reliable evidence to reveal different transfer pathways of Cd and its phytoavailability in paddy systems.

Ecological pollution features and health risk exposure to heavy metals via street dust and topsoil from Nkpor and Onitsha in Anambra, Nigeria

The manuscript presents the investigation results on the pollution and risk of metal mines, and it is considered an important report on environmental pollution near mines in Nigeria, with archival value. The research involved soil sampling and heavy metal analysis for about 12 months in three metal mines. Based on these results, the paper provides information on pollution levels and hazards using well-known methods like pollution and ecological risk indexes. The increasing population in urban communities attracted by various industrial, economic and social activities causes contamination of atmospheric environment that can affect human health. We investigated heavy metal distributions, correlation coefficient among elements, ecological indices and probable health risk assessment in street dust and topsoil from Nkpor and Onitsha urban suburb, Nigeria. The mean concentration of heavy metals in car dust from Onitsha and Nkpor suburb follows thus: Fe > Mn > Cu > As > Pb > Ni > Cr. The decreasing trend of heavy metal in rooftop dust from both area: Fe > Mn > Cu > Pb > As > Ni > Cr whereas metal contents in topsoil were: Fe > Mn > Cu > Pb > Ni > Cr > As for both areas. The degree of pollution indices was characterized by contamination factor (CF), geo-accumulation factor (I-geo), pollution load index (PLI), Nemerow (PN), ecological and potential ecological risk index (ER and PERI) which indicated low pollution in the urban street environment. The results of Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) showed that the estimated heavy metals displayed sources from atmospheric deposition, natural origin and anthropogenic sources. Risk assessment revealed that ingestion of dust and soil was the significant route for heavy metals exposure to the populace followed by inhalation, then dermal contact. Considering all factors, non-cancer risk was more prominent in children than adults and no significant health hazard could be attributed to both aged groups as of the period of study except for As and Ni that needs constant monitoring to avoid exceeding organ damaging threshold limit of 1 × 10-4.

Risk assessment of heavy metals in agricultural soil based on the coupling model of Monte Carlo simulation-triangular fuzzy number

Soils in areas wherein agriculture and mining coexist are experiencing serious heavy metal contamination, posing a great threat to the ecological environment and human health. In this study, heavy metals (As, Cd, Cr, Cu, Ni, Pb, and Zn) in agricultural soil samples from mining areas were analyzed to explore pollution status, bioavailability, potential sources, and ecological/health risks. Particularly, the coupling model of Monte Carlo simulation-triangular fuzzy number (MCS-TFN) was established to quantify ecological/health risks accurately. Results showed that Cd was heavily enriched in soil and had the highest bioavailability based on both geo-accumulation index (Igeo) and chemical speciation analysis. Pollution sources apportioned with the absolute principal component score-multiple linear regression (APCS-MLR) model demonstrated that heavy metals were mainly derived from agricultural activities, followed by mining activities and natural sources. The MCS-TFN ecological risk assessment classified Cd into the high-risk category with a probability of 40.96%, whereas other heavy metals were categorized as the low risk. Cd was regarded as the major pollutant for the ecosystem. Moreover, the MCS-TFN health risk assessment indicated that As showed high noncarcinogenic risk (0.07% probability) and moderate carcinogenic risk (1.87% probability), and Cd presented low carcinogenic risk (80.19% probability). As and Cd were identified as the main heavy metals that pose a threat to human health. The MCS-TFN risk assessment is superior to the traditional deterministic risk assessment since it can obtain the risk level and the corresponding probability, and significantly reduce the uncertainty in risk assessment.

Assessing the environmental effects of ICT and renewable energy: roles of financial development, innovation, and trade

In today's world of rapidly expanding economies, the fundamental aim of most nations is to raise the quality of living for their citizens. The investigation aims to analyze how environmental rules affect the emergence of environmentally conscious economies. This research focused on China's 26 provinces to investigate the elements influencing green economic development. These components included information and communication technology (ICT), industrial structure (IND), human capital (EDU), and foreign direct investment. Spatial modeling and SBM methods were utilized to show that there is still a connection between the variables after all these years using yearly time series data that began in 2000. Overall, the results suggest that environmental regulation helps green economic development (GDE), whereas industrial structure significantly hinders. Similar to the previous point, information and communication technology has a favorable influence on building a sustainable economy. The problem of ensuring long-term economic growth via information and communication technology is complicated and has scholars engaged in exciting discussion. The expansion of the green economy is also affected by factors such as human capital and foreign direct investment. This study's findings illuminate the economic effects of environmental regulations and support the contention that such laws are necessary for accomplishing the win-win goals of green economic development and environmental protection. This means that the research provides a fresh perspective to consider the monetary effects of environmental restrictions.

Digital technology and its application in supply chain management: new evidence from China's economy

The purpose of this article is to investigate the influence that practices using information technology (IT) have on the development of a competitive advantage across the supply chain. An organization has a competitive advantage when it has qualities that give the required foundations for it to separate itself from other organizations that are also in its industry. Pressure is applied to the corporate environment as a result of competition and ongoing changes, such as the introduction of new products and technical advancements, the decline of product lifestyles, and the proliferation of products. In order to maintain a competitive edge and achieve financial success in business, organizations are necessary for responding to changes in the market. Through the use of supply chain markets, companies are able to react quickly to unforeseen shifts in the market, and these shifts may be turned into lucrative business possibilities. One of the most significant things that firms can do to assist themselves is make use of information technology to improve their supply chain management agility. From March 2021 through January 2022, the area of China will have a total sample size of 247 persons fill out a questionnaire as part of the data collection process. In each and every questionnaire, the measurements were taken using a Likert scale with five points. The partial least square-structural equation modeling (PLS-SEM) approach is used to the causal model in order to assess the model's reliability and validity. This technique is used to evaluate the causal model. The findings indicate that information technology has a favorable impact on the adaptability of supply chain management systems. In addition, the findings that were collected have shown that there are four factors that influence the SCM systems. These factors are the IT skills and knowledge, the integration of IT-based systems, the IT infrastructure, and the design of global position system and geographic information systems. In addition, this research offers practitioners recommendations for implementing digital technology for supply chain management and building suitable business strategies at various stages of digitalization.

Heavy metals and their sources, potential pollution situations and health risks for residents in Adıyaman province agricultural lands, Türkiye

In this study, the contents of heavy metals (HMs) such as Al, Cd, Co, Cr, Cu Fe, Mn, Ni, Pb and Zn in soil samples collected from 403 sampling locations of the agricultural lands of Adıyaman Province (Türkiye) were determined by Inductively Coupled Plasma‒Optical Emission Spectrometry (ICP‒OES). The mean concentrations of Al, Cd, Co Cr, Cu Fe, Mn, Ni, Pb and Zn HMs were detected 28,986, 3.60, 15, 127, 52.67, 45,830, 817, 62.40, 10.75 and 66.25 mg kg^-1, respectively. These results showed that the average concentrations of Cd, Cr, Cu, Fe, Mn and Ni exceeded the Upper continental crust average. To determine and to evaluate the contamination status and distribution of HMs in agricultural soils, metal pollution parameters such as enrichment factor (EF), geoaccumulation index (I_geo), contamination factor (Cf), pollution load index, potential ecological risk factor (Er), and potential ecological risk index (RI) were used. Factor analyses (FA) and principal component analyses (PCA) indicated that Cd, Cr and Ni levels were influenced by anthropogenic sources, Fe by both lithological and anthropogenic sources, and other HMs by lithogenic origins. For both children and adults, the hazard index (HI) and total hazard index (THI) values of HMs were < 1, suggesting that non-carcinogenic health risks to residents through ingestion, inhalation pathways, and dermal contact were currently absent. In addition, the cumulative carcinogenic risk (CCR) results were within the acceptable risk range (10^-4 to 10^-6). The results showed that children were more sensitive to the non-carcinogenic and carcinogenic effects of HMs.

The spillover of tourism development on CO2 emissions: a spatial econometric analysis

Climate change and tourism's interaction and vulnerability have been among the most hotly debated topics recently. In this context, the study focuses on how CO₂ emissions, the primary cause of global warming and climate change, respond to changes in tourism development. In order to do so, the impact of tourism development on CO₂ emissions in the most visited countries is investigated. A panel data from 2000 to 2017 for top 70 tourist countries are analysed using a spatial econometric method to investigate the spatial effect of tourism on environmental pollution. The direct, indirect, and overall impact of tourism on CO₂ emissions are estimated using the most appropriate generalized nested spatial econometric (GNS) method. The findings reveal that tourism has a positive direct effect and a negative indirect effect; both are significant at the 1% level. The negative indirect effect of tourism is greater than its direct positive effect, implying an overall significantly negative impact. Further, the outcome of financial development and CO₂ emissions have an inverted U-shaped and U-shaped relationship in direct and indirect impacts. Population density, trade openness, and economic growth significantly influence environmental pollution. In addition, education expenditure and infrastructure play a significant moderating role among tourism and environmental pollution. The results have important policy implications as they establish an inverted-U-shaped relationship among tourism and CO₂ emissions and indicate that while a country's emissions initially rise with the tourism industry's growth, it begins declining after a limit.

Sustainable development and pollution: the effects of CO2 emission on population growth, food production, economic development, and energy consumption in Pakistan

Population growth has been a leading driver of global CO2 emissions over the last several decades. CO2 emission and greenhouse gas emissions are a key issue in the world that affects food production and also causes the climate change. The core purpose of this study was to inspect the influence of carbon dioxide emission to population growth, food production, economic growth, livestock and energy utilization in Pakistan. The STIRPAT (Stochastic Impact by Regression on Population, Affluence and Technology) model with the extension of an ARDL (Autoregressive Distributed Lag) method was utilized to demonstrate the linkage amid variables. Outcomes during short-run investigation reveal that variables population growth, economic growth, rural population growth, livestock production uncovered a productive association with CO2 emission. Furthermore, via long-run population growth, economic growth, rural population growth, livestock production and energy utilization have positive interaction with CO2 emission, while the variables food production and urban population growth demonstrated an adverse influence to CO2 emission during long- and short-run interaction. Similarly, the error correction model exposed that population growth, economic progress, livestock and energy utilization have constructive interaction to CO2 emission, while the variables food production, urban and rural population growth exposed an adverse impact to CO2 emission. On the basis of this analysis, we will address the strategic consequences.

Microplastics as a vehicle of heavy metals in aquatic environments: A review of adsorption factors, mechanisms, and biological effects

Microplastics (MPs) have recently attracted much attention due to their widespread distribution in the aquatic environment. Microplastics can act as a vector of heavy metals in the aquatic environment, causing a potential threat to aquatic organisms and human health. This review mainly summarized the occurrence of microplastics in the aquatic environment and their interaction with heavy metals. Then, we considered the adsorption mechanisms of MPs and heavy metals, and further critically discussed the effects of microplastics properties and environmental factors (e.g., pH, DOM, and salinity) on the adsorption of heavy metals. Finally, the potential risks of combined exposure of MPs and heavy metals to aquatic biota were briefly evaluated. This work aims to provide a theoretical summary of the interaction between MPs and heavy metals, and is expected to serve as a reference for the accurate assessment of their potential risks in future studies.

Rethinking of Environmental Health Risks: A Systematic Approach of Physical-Social Health Vulnerability Assessment on Heavy-Metal Exposure through Soil and Vegetables

In the field of environmental health risk assessment and management research, heavy metals in soil are a constant focus, largely because of mining and metallurgical activities, and other manufacturing or producing. However, systematic vulnerability, and combined research of social and physical vulnerability of the crowd, have received less attention in the research literature of environmental health risk assessment. For this reason, tentative design modelling for comprehensive environmental health vulnerability, which includes the index of physical and social vulnerability, was conducted here. On the basis of experimental data of heavy-metal pollution in soil and vegetables, and population and societal survey data in Daye, China, the physical, social, and comprehensive environmental health vulnerabilities of the area were analyzed, with each village as an evaluation unit. First, the polluted and reference areas were selected. Random sampling sites were distributed in the farmland of the villages in these two areas, with two sampling sites per village. Then, 204 vegetable samples were directly collected from the farmland from which the soil samples had been collected, composed of seven kinds of vegetables: cowpea, water spinach, amaranth, sweet potato leaves, tomato, eggplant, and pepper. Moreover, 400 questionnaires were given to the local residents in these corresponding villages, and 389 valid responses were obtained. The results indicated that (1) the average physical vulnerability values of the population in the polluted and reference areas were 3.99 and 1.00, respectively; (2) the village of Weiwang (WW) had the highest physical vulnerability of 8.55; (3) vegetable intake is exposure that should be paid more attention, as it contributes more than 90% to physical vulnerability among the exposure pathways; (4) arsenic and cadmium should be the priority pollutants, with average physical vulnerability value contributions of 63.9% and 17.0%, respectively; (5) according to the social vulnerability assessment, the village of Luoqiao (LQ) had the highest social vulnerability (0.77); (6) for comprehensive environmental health vulnerability, five villages near mining activities and two villages far from mine-affected area had high physical and social vulnerability, and are the urgent areas for environmental risk management. In order to promote environmental risk management, it is necessary to prioritize identifying vulnerable populations in the village-scale dimension as an innovative discovery.

Probabilistic-fuzzy risk assessment and source analysis of heavy metals in soil considering uncertainty: A case study of Jinling Reservoir in China

Considering the uncertainty caused by the random error of the sample measurement, the heterogeneity of spatial and temporal distribution of pollutants, and the traditional method of selecting a single parameter for evaluation, based on fuzzy theory, Hakanson potential ecological risk index (considering heavy metal enrichment, ecotoxicity and bioavailability) and United States Environmental Protection Agency health risk assessment system, the fuzzy ecological risk and health risk assessment methods for of heavy metals in soil were established. In the soil of the Jinling Reservoir area, Cd, which has high bioavailability, had the highest average contribution rate to RI, and thus was, regarded as a priority metal for ecological risk. Sites JL9 and JL11 were the priority areas. The heavy metals did not pose a clear hazard to human health, but children had a higher health risk. Pb and As were regarded as the priority metals for health risk. Fuzzy evaluation provided the risk interval and membership degree, contained more parameter information, quantified and reduced the uncertainty of parameters, provided more comprehensive results, and compensated for the deficiency of deterministic evaluation. As the main source of heavy metals, the intensity of agricultural activities in the study area must be controlled to avoid excessive input and accumulation of heavy metals, which may damage the ecological environment and endanger human health.

Divergent patterns of heavy metal accumulation in paddy fields affect the dietary safety of rice: a case study in Maoming City, China

The objective of this work was to study the impact of large petrochemical plants and mining operations on the accumulation of heavy metals in farmland and rice, as well as assess their potential risks on human health. The contents of seven heavy metals, Cd, Pb, Cr, Ni, Co, Cu, and Mn, were monitored in a typical polluted paddy soil-rice system near a petrochemical plant and mining area in Maoming, China. The results showed that the content of Cd in the soil exceeds the standard rate by 100%, and the single factor pollution index of Cd was 5.12, which is considered heavy pollution. Excessive heavy metals can inhibit and poison the growth of rice plants. Rice plants can maintain a certain level of heavy metal content by reducing the absorption or interception in the root cells, leading to great differences in the distribution of different heavy metals in plant tissues. Cadmium, Cu, Co, and Mn are easily absorbed from the soil by rice roots, while other heavy metals are relatively difficult to absorb by rice roots. Cuprum, Cd, Co, Pb, and Cr were mainly accumulated in the root of rice, but Mn and Ni migrate to the above ground plant tissues quickly. The brown rice produced in the paddy fields in the study area was seriously polluted. The concentration of Cd, Pb, and Ni in brown rice exceeded the standard by 100%, and Cr in brown rice also exceeded the standard by 80%. If residents consume rice from the study area, their daily intake of Cr and Cd will be 1.02 and 3.24 times higher, respectively, than the standard limit recommended by the FAO/WHO. The irrigation streams were polluted due to the discharge of petrochemical plants and mining wastewater, causing the serious pollution of heavy metals in the surrounding paddy fields. The rice produced in this area poses a serious risk to consumers, and so this problem of pollution should be addressed.

Exploring human health risk assessment based on the screening of primary targeted metal and chemical balance simulation of ionic speciation in an industrial area, China

A comprehensive human health risk assessment methodology based on major hazard element screening and morphological evolution simulation is proposed. The primary targeted metal (PTM) screened by classical health risk assessment was introduced into chemical balance simulation to obtain speciation distribution and corresponding risk. According to the results of risk assessment of morphological evolution of primary targeted metal (PTM), a potential methodology for the remediation is proposed, which could reduce the risk level efficiently and quickly by changing the pH of soil environment with additional acid and alkali substances. A case study was performed in a dye factory in Suzhou city, Jiangsu Province, China. The results of classical health risk assessment showed that the regional health risk index for children exceeded tolerance value of 1, in which Cr accounted for high risk level of 61%. Chemical balance simulation results showed that CrO₄^2- and CaCrO₄ had the highest risk index, and the change of pH value would affect the proportion of CrO₄^2- and CaCrO₄ in Cr⁶⁺ ionic speciation, which may indirectly change the risk level. It is recommended to adjust the pH of the soil environment to quickly reduce regional human health risk. This study will provide a theoretical basis for public health protection and site restoration management.

Exploring the multi-dimensional coordination relationship between population urbanization and land urbanization based on the MDCE model: A case study of the Yangtze River Economic Belt, China

The rapid development of urbanization has had a dramatic impact on the economy, society and environment in China. In this context, the coordination relationship between population urbanization and land urbanization is essential for achieving sustainable urbanization. Based on the statistical data from 2007-2017 in the Yangtze River Economic Belt (YEB), this paper established the multi-dimensional coordination evaluation (MDCE) model by using the speed coordination evaluation (SCE) model, the level consistency evaluation (LCE) model, the entropy method and the space matching evaluation (SME) model to evaluate the coordination relationship between population urbanization and land urbanization from the speed-level-space perspective. The results showed that from 2007 to 2017: 1) the development speed of population urbanization and land urbanization in the YEB were more and more coordinated, and the speed of population urbanization lagged behind that of land urbanization. In addition, the overall development speed of the 11 provinces declined, and most of them were characterized by excessive development of land urbanization. 2) the development level of population urbanization and land urbanization in the YEB were all high, but the development level of population urbanization was lower than that of land urbanization. Further, the development level of the 11 provinces remained stable and high, and continuously improved. 3) the space matching of population urbanization and land urbanization in the YEB had a high degree of coordination, and the space matching degree of population urbanization was higher than that of land urbanization. Moreover, the space matching of most provinces in the region had declined, but the change was small. Finally, this paper proposes the policy recommendations on the coordinated development of population and land urbanization at the institutional, market and management levels to achieve coordinated and sustainable urbanization.

Spatial-temporal characteristics, source-specific variation and uncertainty analysis of health risks associated with heavy metals in road dust in Beijing, China

Based on the concentrations of ten heavy metals (As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, Zn, Fe) in 144 road dust samples collected from 36 sites across 4 seasons from 2016 to 2017 in Beijing, this study systematically analyzed the levels and main sources of health risks in terms of their temporal and spatial variations. A combination of receptor models (positive matrix factorization and multilinear engine-2), human health risk assessment models, and Monte Carlo simulations were used to apportion the seasonal variation of the health risks associated with these heavy metals. While non-carcinogenic risks were generally acceptable, Cr and Ni induced cautionary carcinogenic risks (CR) to children (confidence levels was approximately 80% and 95%, respectively).. Additionally, fuel combustion posed cautionary CR to children in all seasons, while the level of CR from other sources varied, depending on the seasons. Heavy metal concentrations were the most influential variables for uncertainties, followed by ingestion rate and skin adherence factor. The values and spatial patterns of health risks were influenced by the spatial pattern of risks from each source.

Ecological risk, health risk assessment, and pollution source analysis of Xinli Lake wetland based on triangular fuzzy number

Wetland environmental pollution has become a global problem involving the ecological environment and human health. This study measured the concentration of seven potentially toxic elements (PTEs Hg, Cd, Zn, Cu, Cr, Pb, and As) in the soil upstream of the Xinli Lake wetland in China. Based on the fuzzy theory, the sources, spatial distribution, ecological risks, and health risks of pollutants are studied. The result shows that the concentrations of the seven potentially toxic elements are close to or exceed the background value, and their spatial distribution showed irregular changes. The soil upstream of the wetland has not been seriously polluted, and Cd, which has higher bioavailability, is the priority element for ecological risk. Pollutants do not harm human health; children face higher health risks; Pb and As have the highest carcinogenic and non-carcinogenic risks, respectively. Zn, Cu, Cr, Pb, and As in the study area are derived from agricultural activities, while Hg and Cd are mainly affected by soil-forming parent materials. Attention should be paid to controlling the intensity of agricultural activities to avoid excessive input and accumulation of pollutants that would harm the ecological environment and human health.

Effects of dry-wet cycles on mechanical and leaching characteristics of magnesium phosphate cement-solidified Zn-contaminated soils

Although magnesium phosphate cement (MPC) is conventionally deemed effective in heavy metal-contaminated soil remediation, the variations of its mechanical and leaching characteristics under the action of dry-wet cycles remain unclear as yet. This paper primarily addressed the effect of dry-wet cycles and fly ash on MPC-solidified zinc-contaminated soil via a disparate group of experiments. In this study, solidified cylindrical samples were subjected to different drying-wetting cycles ranging in times from 0 to 10 with varying content of fly ash. We then measured the mass loss, the unconfined compressive strength, and the Zn²⁺ leaching concentration of the leachate for the samples undergoing specified cycles. In addition, X-ray diffraction (XRD) and scanning electron microscopy (SEM) tests were conducted to explore the mechanism of MPC-solidified zinc-contaminated soil with fly ash. The results indicate that the Zn²⁺ concentration in the leaching solution increases rapidly with the number of cycles for 0-3 cycles and then tends to flatten out. Moreover, the unconfined compressive strength of the samples without fly ash decreases with an increasing dry-wet cycles. For the samples with various fly ash contents, in contrast, their unconfined compressive strength experiences an initial rise and a subsequent decline owing to the development of dry-wet cycles. With the purpose of facilitating practical applications, the appropriate fly ash content (approximately 20%) was estimated in terms of the enhanced dry-wet cycles durability of the solidified soil and unconfined compressive strength, according to the limited experimental measurements undertaken (for the Zn²⁺ concentration of 0.5). The role of dry-wet cycles in the physical and leaching properties of MPC-solidified soil may be of major practical significance.

Elucidating the distribution and sources of street dust bound PAHs in Durgapur, India: A probabilistic health risk assessment study by Monte-Carlo simulation

Spatial and seasonal distribution of PAHs, source identification, and their associated carcinogenic health risk was investigated in street dust of Durgapur, India. Street dust is an important indicator to detect the quality of the environment as well as the sources of pollutants. The obtained results showed fluctuation in PAHs concentrations from 2317 ± 402 ng/g to 5491 ± 2379 ng/g along with the sampling sites. Seasonal variation revealed higher PAHs concentrations in the winter season (5401 ± 993 ng/g) with the maximum presence of 4-ring PAHs. Two-way analysis of variance (ANOVA) exposed that the sites, seasons and site-season interactions were vividly affected by dissimilar PAHs. The PAHs source identification was investigated by principal component analysis (PCA), positive matrix factorization (PMF), diagnostic ratios, and they revealed pyrogenic, diesel, gasoline, wood and coal combustion to be the key sources of the PAHs in street dust. Obtained results from incremental lifetime cancer risk (ILCR) model exhibited the carcinogenic risk for children ranged from 2.4E-06 to 3.8E-06 while 2.1E-06 to 3.4E-06 for adults which were above the baseline value 1.0E-06. The Monte Carlo simulation model identified cumulative cancer risk of sixteen PAHs in 50th percentile were 2.8 and 1.7 times more while in 95th percentile, the values were 8.8 and 7.8 times higher than the acceptable value of 1E-06 for child and adult respectively.

Potentially toxic elements in the Middle East oldest oil refinery zone soils: source apportionment, speciation, bioaccessibility and human health risk assessment

In this research, fifteen potentially toxic elements (PTEs) (Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sb, Sc and Zn) were analysed and quantified in samples collected at 44 sites in an urban area of Iran. Sources were apportioned using enrichment factors (EFs), modified pollution index (MPI), principal component analysis (PCA), multivariate linear regression of absolute principal component scores (MLR-APCS) and speciation, with a focus on anthropogenic PTEs in the urban and industrial soils of the Arvand Free Zone area, an oil-rich zone in the country. Furthermore, the bioaccessibility and the human health risks of PTEs were investigated. The EF revealed a significant enrichment for elements such as Cd, Cu, Hg, Mo, Pb, Sb and Zn. Values of MPI showed that Abadan industrial district and Abadan petrochemical complex are the most polluted sites in the study area.The PCA/MLR analysis revealed four main sources: natural sources, fossil fuel combustion, traffic and oil derivatives and petroleum waste. The relative contribution of each source to PTE concentration varied from 32.3% of the natural sources to 30.6% of traffic and from 20.1% of petroleum waste to 17% of fossil fuel combustion. The source apportionment of metals generated using MLR-APCS receptor modelling revealed that 85.0% of Hg was generated by oil products. Chemical speciation results were compatible with the results obtained from PCA. Bioaccessibility of PTEs decreased from gastric to intestinal phase except Mo and Sb due to their different geochemical characteristics. Hazard index (HI) for non-cancer risk of PTEs for both children and adults based on total element concentrations was estimated to range from 2-fold to more than 10-fold higher than that of bioaccessible phases.

Speciation and migration of heavy metals in sediment cores of urban wetland: bioavailability and risks

To examine the status and risk of heavy metal pollution in an urban wetland in China, the distribution and speciation of chromium (Cr) and other metals (Cd, Cu, Pb, and Zn) were examined. We investigated the impact of three major land uses (residential and industrial (RI), orange plantation (OP), and mixed OP and RI (OPRI)) on the heavy metal characteristics using sediment cores (0-60 cm below water/sediment interface) collected in Sanyang Wetland, China. It was found that all the metals (Cr, Cd, Cu, Pb, and Zn) had lower concentrations in the top layers but higher contents in the bottom layers of sediments. Species of metals in sediments were dominated by their secondary phase (i.e., exchangeable and carbonate bound, Fe-Mn bound and organic bound) with relatively low contents of primary phase (i.e., residual form), except for Cr in RI affected river sediments that had a relatively high content of primary phase (20.97-36.07%). The ratio of secondary phase to primary phase (RSP) and risk assessment code (RAC) methods were applied to assess environmental risk. The results implied that the metal mobility and bioavailability could significantly cause urban wetland environmental quality decline, and thus enhanced strategies should be required to target the capture and removal of metals.

Source-specific ecological risk analysis and critical source identification of heavy metals in road dust in Beijing, China

To explore the spatial variation of source-specific ecological risks and identify critical sources of heavy metals in road dust, 36 road dust samples collected in Beijing in March 2017 were analyzed for heavy metals. A new method that takes into consideration the heavy-metal toxic response and is flexible to changes in the number of calculated heavy metals, called the Nemerow integrated risk index (NIRI), was developed for ecological risk assessment. The NIRI indicated that heavy metals posed considerable to high risks at the majority of sites, and 22 % of the sites suffered extreme risk in spring (NIRI > 320). Four main sources were identified based on positive matrix factorization (PMF): traffic exhaust, fuel combustion, construction, and use of pesticides and fertilizers. Owing to the lower toxic response factors of representative heavy metals of fuel combustion than those of other sources, although fuel combustion had the highest contribution (34.21 %) to heavy metals in spring, it only contributed 5.57 % to ecological risks. Critical sources and critical source areas were determined by considering the contributions to both heavy metals and ecological risks. The use of pesticide and fertilizer and traffic-related exhaust were identified as critical sources of heavy metals in spring. Source-specific ecological risks and critical sources of heavy metals changed with the changing seasons, which suggests that different strategies should be adopted in different seasons.

Source apportionment of soil contamination based on multivariate receptor and robust geostatistics in a typical rural–urban area, Wuhan city, middle China

In this study topsoil samples were collected from 57 sites of Dongxihu District which is a typical Chinese urban–rural combination area, to analyze the causes and effects of 6 heavy elements. (Ni, Pb, As, Cu, Cd, and Hg) Pollution of Enrichment factor, multivariate statistics, geostatistics were adopted to study the spatial pollution pattern and to identify the priority pollutants and regions of concern and sources of studied metals. Most importantly, the study area was creatively divided into central urban, semi-urbanized, and rural areas in accordance with the characteristics of urban development and land use. The results show that the pollution degree of potential ecological risk assessment is Hg>Ni>Cu>As>Cd>Pb, and semi-urban regions> city center> rural areas. Results based on the proposed integrated source identification method indicated that As was probably sourced from agricultural sources (33.99%), Pb was associated with atmospheric deposition (50.11%), Cu was related to industrial source 1 (45.97%), Cd was mainly derived from industrial source 2 (42.97%) and Hg come mainly from industrial source 3 (56.22%). The pollution in semi-urban areas in urbanization need more attention.

Environmental, ecological and health risks of trace elements, and their sources in soils of Harran Plain, Turkey

Soil pollution with trace elements (TEs) has become an increasingly serious environmental concern, however, assessment of ecological and human health risks especially in intensive agricultural regions remains limited. In this study, the contents of ten TEs (Al, As, Pb, Cr, Cu, Zn, Ni, Co, Mn and Fe) in soil samples from 204 sampling sites in the Harran Plain (Turkey) were examined to evaluate possible sources, pollution status and environmental, ecological and health risks of these elements. Only As and Ni exceeded the upper continental crust concentrations. Among ten TEs, Ni and As had the highest mean values of enrichment factor (EF) and contamination factor (Cf), indicating that soils showed moderate enrichment and moderate contamination with these elements. Ecological risk factor and ecological risk index values of all samples were <40 and <150, respectively, indicating low ecological risk in the study area. Factor analysis and correlation analysis indicated that Al, Pb, Cr, Cu, Zn, Co, Mn and Fe mainly originated from natural sources, Ni from mixed sources of anthropogenic and lithogenic origins, while arsenic primarily originated from anthropogenic activities. The hazard quotient values for both adults and children did not exceed 1, suggesting that all TEs in soil through ingestion, dermal contact and inhalation pathways had no significant non-carcinogenic risks. Children were more susceptible to non-carcinogenic health effects of TEs in soils. The carcinogenic risk values of As, Co, Cr and Ni were within the acceptable risk range, indicating that carcinogenic risks were not expected.

Health risk assessment and bioaccessibilities of heavy metals for children in soil and dust from urban parks and schools of Jiaozuo, China

Urban parks and schools sever as the mainly activity areas for children, but risk assessment posed by heavy metals (HMs) from soil and dust in these area has rarely been investigated. In this study, six urban parks and seven schools in Jiaozuo, China, were taken as research objects to understand the contamination level and bioaccessibility of HMs from soil and dust in urban parks and schools. The results indicated that Zn, Cu, Pb, Cd, As, Ni and Co from soil and dust were above the background values, especially Zn and Cd in dust, and As and Cd in soil. Serious Cd pollution was discovered, and respective Cd concentrations in soil and dust were 17.83 and 7.52 times the background value. Additionally, the average concentration and bioaccessibility of Zn, Mn, Pb, Cd, Cr, Ni and Co in dust were both higher than in soil. High concentration and high bioaccessibility of HMs in dust suggested that HMs contamination were serious and universal in Jiaozuo. The concentrations of most HMs were higher in the gastric phase, except for Cu and Cd which remained higher in the intestinal phase. Both in the gastric phase and intestinal phase, Mn, As and Cd in soil and dust both have high bioaccessibility which all exceed 10%. The carcinogenic and non-carcinogenic risks base on the total HMs for children (soil: 7.93, 1.96E-05; dust: 6.44, 3.58E-05) were greater than those for adults (soil: 6.35E-01, 1.32E-05; dust: 5.06E-01, 2.42E-05), and urban parks and schools posed high potential risk for children. Therefore, assessment the risk posed by HMs contamination of soil and dust in urban parks and schools is vital and urgent for children.

Environmental Risk Perception, Risk Culture, and Pro-Environmental Behavior

Mixed evidence exists regarding the relationship between environmental risk perception and pro-environmental behavior. This study uses an existing online survey conducted by the Center of Ecological Civilization (CEC) of China University of Geosciences from December 2015 to March 2016 and examines how cultural bias influences environmental risk perception and behavior. We found that an individual’s pro-environmental behavior is not only influenced by environmental risk perception, but also by his or her cultural worldviews. Built on culture theory (CT), our empirical results suggest that young Chinese people are more located in “high-group” culture, where egalitarian culture and hierarchical culture dominate. The higher scores of hierarchical and egalitarian cultures of Chinese youth, the more likely they are to protect the environment. Moreover, the relationship between cultural worldviews and pro-environmental behaviors are mediated by perceived environmental risks.

Insight into the cadmium and zinc binding potential of humic acids derived from composts by EEM spectra combined with PARAFAC analysis

To investigate the characteristics of humic acids (HAs) and the combined effects of HAs on heavy metals, three HAs derived from kitchen waste compost (KW), pig manure compost (PM), and green waste compost (GW) were exposed to Cd(II) and Zn(II). The elemental contents and functional groups of HAs were different due to different raw materials. Fulvic-, humic-like content C1, humic-like content C4, and two protein-like contents C2 and C3 were identified in three HAs by EEM-PARAFAC analysis. The effects of HAs on heavy metals were associated with the metal species and HA source. Our results reveal that titrating Cd(II) caused stronger fluorescence quenching compared to titrating Zn(II) for all HAs. C1 and C4 of KW-HAs and PM-HAs showed fluorescence quenching after Cd(II) was added, whereas negligible fluorescence quenching was found when Zn(II) was added. In addition, C1 and C4 in the GW-HAs did not show obvious fluorescence quenching regardless of whether Cd(II) or Zn(II) was added. C3 in all HAs caused significant fluorescence quenching, suggesting that C3 plays an important role affecting the mobility of heavy metals. Consequently, these results suggest that HAs from KW and PM have greater potential for Cd-contaminated soil remediation than those from GW.

The mechanisms of PM2.5 and its main components penetrate into HUVEC cells and effects on cell organelles

Atmospheric particulate matter (PM_2.5) is associated with the morbidity and mortality of cardiovascular diseases. However, whether PM_2.5 penetrates into the cells and the potential mechanisms are unknown. Hence, the study firstly indicated that PM_2.5 could penetrate into the HUVEC cells, and phagocytosis, micropinocytosis, caveolin as well as clathrin mediated the internalization of PM_2.5 into HUVEC cells. Particularly, the components of PM_2.5-Metal, PAHs and WSC could enter into HUVEC cells mainly via the micropinocytosis, clathrin and caveolin mediated endocytosis, respectively. The current data of environmental assessments indicated that PM_2.5-Metal were extremely harmful to the ecological environment and human health. Moreover, accompanying with mitochondrial fusion gene Mfn1 was increased and fission genes Opa1 and Drp1 were decreased, and the lysosome related genes LAMP2 and LAMP3 were decreased, the phenomenon that the morphology of mitochondrial and lysosome injured was observed in HUVEC cells treated with PM_2.5 and/or PM_2.5-Metal. These data suggest that PM_2.5 and its main components depend on different endocytosis penetrate into HUVEC cells and cause the mitochondrial and lysosomal damages. Thereby, our study provides the potential mechanism of haze particles penetration into HUVEC cells and damage to organelles.

A potential reusable fluorescent aptasensor based on magnetic nanoparticles for ochratoxin A analysis

An aptasensor for the detection of ochratoxin A (OTA) in environmental samples was developed. It displayed high sensitivity and good selectivity. Factors such as specific binding between a FAM (5-carboxyfluorescein)-labeled aptamer (f-RP) and OTA, and a magnetic property of a streptavidin magbeads-modified capture probe (bm-CP) resulted in aptasensor’s linear relationship between fluorescence intensity and the concentration of OTA. This characteristic is present at the OTA concentration ranges from 0.100 μM to 25.00 μM with a LOD (limit of detection) of 0.0690 μM. The bm-CP can be reused through melting, washing and magnetic separation, which contributes to cost reduction. In addition, the proposed method is simple and detection process is fast. The aptasensor can be used in real samples.

Fuzzy synthetic evaluation and health risk assessment quantification of heavy metals in Zhangye agricultural soil from the perspective of sources

Heavy metals in agricultural soil receive much attention because they are easily absorbed by crop into the ecosystem. Managing the discharge of heavy metals from the source is an effective way to prevent and control heavy metals pollution. Grouped principal component analysis (GPCA) and Positive Matrix Factorization (PMF) receptor models were utilized in this study to conduct source apportionment, and the former was optimal because of the accuracy of predicting. Based on the source contribution by GPCA/APCS, heavy metals were evaluated by fuzzy synthetic evaluation model and health risk assessment model. The results of source apportionment showed that heavy metals in Zhangye agricultural soil were mainly affected by steel industry, traffic, agrochemicals, manures, mining activities, leather industry and metal processing industry source. Fuzzy synthetic evaluation showed that the pollution levels of Chromium (Cr) derived by leather industry and metal processing industry and Nickel (Ni) derived by steel industry and traffic source were higher. Health risk assessment revealed that the non-carcinogenic and carcinogenic risks of Cr derived by leather industry and metal processing industry and Lead (Pb) derived by steel industry and traffic source were higher.

Environmental risk assessment in livestock manure derived biochars

Livestock-manure-derived biochar is one of major products obtained from the pyrolysis of livestock manure. This study quantitatively assesses the pollution level and ecological risks associated with heavy metals in livestock manure and the biochar produced by its pyrolysis. The geo-accumulation index (GAI) values of heavy metals in livestock manure were significantly decreased (P < 0.05) and indicated to be at the grade of uncontaminated expected for Zn in pig-manure-derived biochar (PMB, 0.94, 800 °C) via pyrolysis. Therefore, Zn should be paid more attention in PMB. The risk factors (E r i ) result shows that heavy metals in biochars were significantly decreased (P < 0.05) with increasing pyrolysis temperature. Potential ecological risk index values revealed that the integrated risks from the heavy metals were significantly decreased (P < 0.05) after pyrolysis. Similarly, the risk assessment code values indicated that the risks from the heavy metals in livestock-manure-derived biochars were significantly decreased (P < 0.05) after pyrolysis. In summary, pyrolysis represents an effective treatment method for livestock manure and can provide an effective method to reduce the risks of environmental pollution.

Geochemical determination and pollution assessment of heavy metals in agricultural soils of south western of Iran

Soil contamination with heavy metals due to the application of fertilizers and biocides in agricultural activities is a potential threat for human health through the food chain. The present work was designed to study the spatial distribution of heavy metals, pollution level and possible reasons for their contamination in agricultural soils of Aghili plain, Khuzestan, Iran. The median concentrations of As, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, V, Zn, and Hg were 2.90, 0.29, 8.10, 39.0, 17.75, 354.0, 0.97, 58.35, 5.90, 34.0, 42.0, and 0.01 mg/kg, respectively. The results revealed that average concentrations of all studied heavy metals with an exception of Co, Cu, and Ni, were lower than background values. Analysis of source identification showed that Zn, Pb, and Cu (P < 0.01, r > 0.9) and Co, Cr, Mn, Ni, and V (P < 0.01, r > 0.7) were mainly from anthropogenic. In addition, Cd probably was originated from agricultural activities (application of manure and phosphorous fertilizers). Enrichment factor values of all metals (except Ni), were in the range of non to moderate enrichment (EF < 5). According to the degree of contamination (C_d) and ecological risk factor (ERF), all stations were categorized as low to moderate contaminated sites (4.5 < C_d < 17), and biological communities in some locations may be at risk (ERF >65). Results indicate that application of fertilizers, herbicides and pesticides in agricultural soils has led to soil contamination and special management and educational plans are needed for public and farmers to prevent further adverse effects.

Scenario Analysis on Energy Consumption and CO2 Emissions Reduction Potential in Building Heating Sector at Community Level

Energy consumption and carbon emissions of building heating are increasing rapidly. Taking Liaobin coastal economic zone as an example, two scenarios are built to analyze the potential of energy consumption and CO2 emissions reduction from the aspects of laws, regulations, policies and planning. The baseline scenario refers to the traditional way of energy planning and the community energy planning scenario seeks to apply community energy planning within the zone. Energy consumption and CO2 emission are forecast in two scenarios with the driving factors including GDP growth, changes in population size, energy structure adjustment, energy technology progress, and increase of energy efficiency. To improve accuracy of future GDP and population data prediction, an ARIMA (Autoregressive Integrated Moving Average model) (1,1,1) model is introduced into GDP prediction and a logistics model is introduced into population prediction. Results show that compared with the baseline scenario, energy consumption levels in the community energy planning scenario are reduced by 140% and CO2 emission levels are reduced by 45%; the short-term and long-term driving factors are analyzed. Policy implications are given for energy conservation and environmental protection.

Distribution, Ecological Risk Assessment, and Bioavailability of Cadmium in Soil from Nansha, Pearl River Delta, China

Background: Cadmium (Cd) pollution poses a threat to human health. Examination of the spatial distribution of Cd in soils can be used to assess the risks posed to humans and the environment. Objective: This study determined the enrichment rules and factors influencing Cd pollution in Nansha, and evaluated the pollution characteristics and bioavailability of Cd in quaternary sediments through 7 deep soil profiles (0-200 cm), 4 boreholes, and 348 topsoil (0-20 cm) samples. Methods: The geo-accumulation index (Igeo) and the potential ecological risk index (Er) were used to assess ecological risk, and bioavailability was determined using multivariate, spatial distribution, and correlation matrix analyses. Results: From the Er, 52% of Nansha was classed as being at very high risk of Cd pollution; a further 36% was classed as dangerous. Cadmium was more abundant in clay soils than in sandy soils. Bioavailable Cd in quaternary sediments was significantly affected by the total Cd, and labile Cd accounted for more than half of the total Cd. Changes in pH mainly affected bioavailable Cd rather than total Cd, affecting the overall bioavailability of Cd. Conclusions: Nansha soils are commonly and seriously contaminated with Cd. An appropriate remediation treatment approach should be used to reduce Cd bioavailability. Furthermore, planting structures in farmland should be adjusted to avoid the impact of heavy metals on human health.

Rare earth elements in paddy fields from eroded granite hilly land in a southern China watershed

There are large amounts of ion-adsorption rare earth resources in the granite red soil region of southern China, and exploitation of rare earth elements (REEs) has caused serious soil erosion and soil pollution in the area. In this study, the spatial variability of soil REEs in Zhuxi watershed, Changting County, southern China, was analyzed using a geostatistics method. The analysis produced several important results: (1) The content of total rare earth elements (TREEs) in the soil samples ranged from 56.04 to 951.76 mg kg-1, with a mean value of 255.34 mg kg-1, which was higher than the background value of soil in China. The REE variables showed strong positive Ce anomalies and strong negative Eu anomalies, with mean values of 2.26 and 0.44, respectively. (2) The contents of TREEs in five subtypes of the soils were different, but they had broadly similar curves of chondrite-normalized REE patterns, with steeper patterns from La to Eu and flatter patterns from Eu to Y. (3) The spatial variability of light rare earth elements (LREEs) was mainly affected by natural factors, but the spatial variabilities of heavy rare earth elements (HREEs) and TREEs were influenced by the combination of natural factors and anthropogenic factors. Soil erosion can contribute significantly to REE migration, especially for HREEs. (4) The distribution of TREEs showed that the high content of TREEs was in the lowland of the western watershed. By comparing the distributions of TREEs in paddy fields and hilly land, we found that the area with a high content of TREEs was greater in paddy fields than in hilly land, so we deduced that REEs migrate from hilly land to the paddy field and accumulate in the soil there.

Nonlinear and Spatial Effects of Tourism on Carbon Emissions in China: A Spatial Econometric Approach

Reducing carbon emissions is crucial to the sustainable development of tourism. However, there are no consistent conclusions about the nexus between tourism and carbon emissions. Considering the possible nonlinear and spatial effects of tourism on carbon emissions, this paper employed spatial econometric models combined with quadratic terms of explanatory variables to explore the nexus between them using Chinese provincial panel data from 2003 to 2016. The main results are as follows: (1) There is a significant inverse U-shaped relationship between tourism development and carbon emissions. In the provinces whose tourism receipts are relatively low, the effects of tourism on carbon emissions are positive but decrease gradually as the tourism receipts increase and then shifts to negative and continues decreasing gradually when the tourism receipts beyond the critical value. (2) For the geographical proximity and industrial relevance, one province’s tourism development not only affects its carbon emissions but also affects its neighbors’ carbon emissions through spatial lag effect (indirect effect) which is also inverse U-shaped. (3) Carbon reduction policies, sustainable education, and transportation infrastructure all have significant moderating effects on the relationship between tourism and carbon emissions, but the moderating effect of the management efficiency of tourism is not statistically significant. Furthermore, improvements to the sustainable education and transportation infrastructure not only strengthen the direct negative effect of tourism on carbon emissions but also strengthen the indirect negative effect of tourism on carbon emissions. This study not only advances the existing literature but is also of considerable interest to policymakers.

The Effects of Energy Consumption, Economic Growth and Financial Development on CO2 Emissions in China: A VECM Approach

As one of the largest energy consumers and the greatest emitter of CO2 in the world, China now confronts the dual challenge of reducing energy use while continuing to foster economic growth. To overcome this issue, there is a need of comprehensive economic, financial, and energy policy reforms to promote sustainable development. The objective of this paper is to examine the effects of economic growth, financial development and energy consumption on carbon dioxide emission (CO2) in China from 1982 to 2017. The study applies Johansen cointegration test and vector error correction model (VECM) to investigate the long-term equilibrium and short-term causality relationship among the four variables. The causality is also checked by using the innovative accounting approach (IAA). The empirical results show the long-term cointegration relationship between them. Evidence shows that a unidirectional Granger causality running from energy consumption to financial development. Financial development and energy consumption have a statistically significant positive impact on CO2 emissions. In the long run, economic growth can curb CO2 emissions. Hence, financial innovation should be encouraged in the country to meet the demand of sustainable development. Nevertheless, optimizing energy structure and increasing the efficiency of energy utilization can never be left out from the process of development. We add light to policy makers with the construction of carbon trading to effectively address greenhouse effects in China.

Application of Set Pair Analysis in a Comprehensive Evaluation of Water Resource Assets: A Case Study of Wuhan City, China

With the rapid development of the social economy, China is suffering from severe water scarcity due to improper management. Evaluation of water resource value is a crucial issue for innovative management in regional water resources. In this paper, in consideration of the complexity and uncertainty of water resources, 15 indicators were selected to establish the assessment system for its value in Wuhan City from the following three aspects, namely the environment, resources, and society. The analytic hierarchy process (AHP) and Entropy Weight Method were combined to calculate the comprehensive weight. An improved set pair analysis (SPA) model was applied to evaluate water resource assets in the period of 2013–2017. For the sake of the dependability of these results, the James Pollution Loss model was utilized to compute loss of water resource value caused by the decline of water quality in the water pollution environment. The results show that the amount of water resource through physical quantitative accounting in Wuhan City fluctuates greatly. The initial change is relatively stable, then surges in 2015 and 2016, but slumps in 2017. The total water resource assets for Wuhan City from 2013 to 2017 are 14.221, 14.833, 28.375, 75.558, and 21.315 billion RMB, respectively. Therefore, water resource value accounting plays an indispensable role in the environmental protection and sustainable development of water, as well as provides a support for comprehensive calculation and management of various valuable natural resources.

How to Maintain a Sustainable Environment? A Spatial Evolution of Urban Atmospheric Pollution and Impact Factors in China

Urban pollution has significantly contributed to the spread of diseases and global warming. The analysis of spatial distribution characteristics of atmospheric pollutants is crucial for making sustainable industrial policy, and environmentally friendly urban planning. In this paper, GeoDa software is used to analyze how sulfur dioxide (SO2), nitrogen oxides (NOx), and smoke dust (DUS) are spatially distributed in various provinces of China. Then, global spatial correlation test and cluster analysis are carried out to obtain the spatial evolution characteristics of three pollutants. Afterward, the spatial panel data model is applied to explore the factors that affect the spatial evolution of SO2, NOx and smoke dust (DUS) nationwide. MATLAB is used to estimate the Spatial Lag Model (SLM) and the Spatial Error Model (SEM) of the three pollutants, respectively. According to our analysis, SEM is more applicable for SO2 and NOx, whereas SLM is optimal for smoke dust (DUS). The results show that foreign direct investment (FDI), industrial structure, and urbanization aggravate environmental pollution, while per capita gross domestic products (per capita GDP) has a negative relationship with the cluster of pollutants. The study concludes by informing public policy makers on environment friendly policies for a more sustainable development.

Can Environmental Tax Policy Really Help to Reduce Pollutant Emissions? An Empirical Study of a Panel ARDL Model Based on OECD Countries and China

Under the background that environmental tax has increasingly become the main means of environmental governance in various countries, it is particularly important to study the effect of environmental tax on reducing pollutants and then put forward suggestions for building a scientific and rational environmental tax system. The novelty of this paper is the investigation of the pollutant emission reduction effects of environmental taxes in Organization for Economic Cooperation and Development (OECD) countries and Chinese provinces at the same time, and further comparison of the pollutant emission reduction effects of environmental taxes in OECD and China under different environmental tax collection scales, industrial added value levels, and economic development conditions based on Auto-Regressive Distributed Lag Modelling Approach (ARDL). The data are derived from environmental taxes and pollutants of OECD countries from 1994 to 2016 and Chinese provinces from 2004 to 2016. The results show that from the overall regression results, environmental taxes really help to reduce pollutant emissions, both in OECD countries and China. From the grouping regression results, the OECD countries and Chinese inland provinces with small-scale or medium-level of environmental tax revenue and higher level of economic growth all show better emission reduction effects, while OECD countries with low industrial added value and Chinese inland provinces with high industrial added value have more significant effects on pollutant emission reduction via environmental taxes.

Spatial distribution and ecological risk assessment of heavy metals in soil from the Raoyanghe Wetland, China

Wetlands are recognized as one of the most important natural environments for humans. At the same time, heavy metal pollution has an important impact on wetlands. China's Raoyanghe Wetland is one of the most important natural wild species gene banks in China. Eight heavy metal elements (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) in surface layer and deep layer soils were analyzed using statistical-, pollution index-, and Nemerow index-based methods, the Hakanson potential ecological risk index method, and principal component and cluster analyses. The results showed that the maximum concentrations of heavy metals exceeded the background values in the core area and buffer zone of the wetland, but the heavy metal content of the soils was generally low and did not exceed 30%. With the exception of Hg, heavy metal concentrations showed strong spatial differentiation. The differences between the surface layer and deep layer soils of the core area were smaller than in the buffer zone. With the exception of Cd, a clear vertical zonation in the buffer zone soils was observed, showing greater evidence of external influences in this zone than the core. With the exception of partial surface soils, which indicated a safe level of pollution in the core area, all other soils were classified as having a ‘mild’ level of pollution. Thus, the wetland is moderately polluted, with both the core area and the buffer zone presenting a low level of potential ecological risk. According to the results of the present study, heavy metal contaminants in the wetland soils were found to be derived mainly from the natural sources.

Does Environmental Tax Affect Energy Efficiency? An Empirical Study of Energy Efficiency in OECD Countries Based on DEA and Logit Model

OECD countries are the largest energy consuming economies in the world, improving energy efficiency and reducing pollution emissions is one of the important goals of the environmental tax policies of OECD countries. Based on the total factor energy efficiency index, this paper establishes an epsilon based measure-data envelopment analysis (EBM-DEA) model to measure the energy efficiency levels of 32 OECD countries during 1995–2016 when undesired outputs are included and not included. The effect of environmental factors on energy efficiency evaluation is compared by efficiency analysis and projection value analysis. On this basis, a Panel Logit model was established to empirically examine the impact of energy taxes on energy efficiency in 32 OECD countries. This paper finds that undesired output has a large impact on the energy efficiency level of OECD countries. Measuring energy efficiency levels without considering undesired outputs tends to lead to overestimation of the energy efficiency level of environmentally friendly countries and underestimate the energy efficiency level of countries that value environmental protection. The collection of energy tax has an important impact on energy consumption efficiency. Without considering the unexpected output, the energy tax has a significant impact on improving the efficiency of coal energy consumption. When considering the unexpected output, the energy tax has a significant impact on improving the efficiency of oil energy consumption. Regardless of the expected output or not, the energy tax has a positive effect on improving the efficiency of natural gas energy consumption. The experimental results also show that the energy structure and energy price have a negative impact on energy efficiency, while the progress of environmental protection technology and industrial structure have a positive impact on energy efficiency. Energy taxes have a “double dividend”. This paper argues that when evaluating a country’s energy efficiency, it should consider the undesired output factors of environmental constraints; governments should pay attention to the role of energy taxes in improving energy efficiency, improve the energy tax system, optimize industrial structure upgrades, stabilize energy prices and support the development of environmental technologies and improve energy efficiency.

Soil organic carbon mineralization in relation to microbial dynamics in subtropical red soils dominated by differently sized aggregates

The dynamics of eroded and retained soil organic carbon (SOC) may provide critical clues for evaluating impacts of soil erosion on global carbon cycling. Distribution patterns of soil aggregates in eroded and deposited environments are shaped by selective transport of water erosion. Therefore, detecting the pattern of SOC mineralization in soils dominated by aggregates of different sizes is essential to accurately explore the dynamics of eroded and retained SOCs in eroded and deposited environments. In the present study, the characteristics of SOC mineralization and its relationship to microbial dynamics in subtropical red soils dominated by different sizes of soil aggregates were investigated. The results demonstrated that the SOC mineralization rate of soils dominated by graded aggregates were significantly different, indicating that SOC mineralization in eroded and deposited environments are shaped by selective transport of water erosion. The highest mineralization rate was found in soils containing 1-2 mm aggregates at the initial stage of the experiment, and the daily average mineralization rate of the < 0.5 mm aggregates was significantly higher than that of the 2-3 mm aggregates. During the incubation, fungal communities exhibited a low dynamic character, whereas the composition of bacterial communities in all treatments changed significantly and had obvious differences relative to each other. Bacterial species diversities and relative abundances in the <0.5mm and the 2-3mm aggregates showed opposite dynamic characteristics. However, there were no statistical interactions between the dynamics of microbial communities and the changes of SOC or soil water content. Changes in bacterial community structure had no significant impact on the mineralization of SOC, which might be related to the quality of SOC or the specific utilization of carbon sources by different functional groups of microorganisms. Mineralization of the eroded and retained SOCs with specific qualities in relation to their functional microorganisms should be further explored in the future.

Fiscal Decentralization, Local Competitions and Sustainability of Medical Insurance Funds：Evidence from China

Local governments are responsible for the management of social medical insurance for urban and rural residents in China. Under the background of fiscal decentralization between the central government and local governments, the strengthening of supervision on medical insurance funds by local governments leads to a reduction in the expenditure of the medical insurance fund, which contributes to its sustainability. By employing the provincial level panel data during 2004–2014, we used a fixed effect model and a spatial autoregression model to investigate whether fiscal decentralization has had a negative influence on the expenditure of China’s new rural cooperative medical system (NCMS) fund. We found that fiscal decentralization has had a significant influence over its per capita expenditure. Our results also indicate that higher fiscal decentralization leads to higher financial aid in the NCMS provided by local governments. Additionally, the expenditure of the NCMS and the local financial aid are influenced by nearby governments. Our results suggest that appropriate fiscal decentralization, which helps to maintain the sustainability of social medical insurance funds, should be encouraged.

A comprehensive risk assessment of metals in riverine surface sediments across the rural-urban interface of a rapidly developing watershed

Metal contamination in aquatic environments is a severe global concern to human health and aquatic ecosystems. This study used several risk assessment indices, to evaluate metal (Cu, Zn, Pb, Cd and Cr) environmental risk of riverine surface sediments across the rural-urban interface of the rapidly developing Wen-Rui Tang River watershed in eastern China. Risk assessments were determined for 38 sites based on the potential ecological risk index (RI), consensus-based sediment quality guidelines (SQGs) and risk assessment code (RAC). Land-use cluster analysis showed that sediments were severely contaminated, especially for Cd, whose concentrations were ∼100 times higher than background levels and had a high proportion in the bioaccessible fraction. According to RI, E_r^Cd was identified with extremely high risk potential, resulting in the highest ecological risk of Cluster 4 (industrial). Similarly, risk within Cluster 4 (industrial) was also ranked highest by SQGs assessment due to the high proportion of industrial land use. Zinc was determined with high risk due to its high concentration compared to its effect range medium (ERM) value. Discrepancies in predicting environmental risks from metals among the three indices were mainly attributed to the contrasting definitions of these metrics. Environmental risk uncertainty derived from spatial variation was further estimated by Monte Carlo simulation and ranked as: Zn > Cd > Cr > Pb > Cu. This comprehensive environmental risk assessment provides important information to guide remediation strategies for management of metal contamination at the watershed scale.

A Fuzzy Comprehensive Assessment and Hierarchical Management System for Urban Lake Health: A Case Study on the Lakes in Wuhan City, Hubei Province, China

Environmental assessment of eutrophication or heavy metals in urban lakes is an important reference for identifying the pollution degree and formulating pollution prevention strategies. At present, the most research on lake health states is often evaluated from a single angle for toxic metals pollution or eutrophication using the standard comparison method for both, the comprehensive trophic level index (TLI), and the health risk assessment for toxic metals. Moreover, the above deterministic methods probably lead to biased or unreliable assessment due to the randomness and fuzziness in environment system caused by natural change and human activities. In this paper, a fuzzy comprehensive lake health assessment method (FCLHAM) was established to evaluate comprehensive lake health states more comprehensively and accurately, which integrates quantitative eutrophication and health risk considerations. To test and verify FCLHAM, 21 lakes, scientifically selected from the total 143 lakes in the Chinese Wuhan city as study case, were investigated and analyzed for their state of eutrophication and the health risk posed by heavy metals. According to the FCLHAM, the average comprehensive lake health state decreased in the sequence of L20 (considerate risk level) > L1⁻L17, L19, L21 (moderate risk level) > L18 (low risk level). Based on the result, lakes were classified into three categories: general management (L18), enhanced management (L1⁻L17, L19, L21), and priority management (L20). If the 143 lakes in Wuhan were classified by the "area-region-function" classification, they would be assigned to the same category as the representative lakes of the same type. At this point, we will attribute all of Wuhan's lakes to the three types. Depending on the characteristics of each type, a targeted approach to different types of management for each type of lake is a more efficient way to manage many of Wuhan's lakes. This management mode also serves as an effective reference for the environmental management of urban lakes both at home and abroad. In other words, according to the FCLHAM, a hierarchical management system based on lake characteristics classification was obtained.