Origin traceability of Cordyceps sinensis based on trace elements and stable isotope fingerprints.

Cordyceps sinensis is a kind of valuable Chinese herbal medicine, and its quality and price depend on the place of origin. Building a traceability system for Cordyceps sinensis products is an effective way to protect Cordyceps sinensis geographical indication products and consumers. In this study, concentrations of 45 trace elements and stable C, N, and Pb isotopes were used to distinguish Cordyceps sinensis samples from different habitats and different varieties (natural and artificial). The results showed that there were significant differences in the isotope compositions of N and Pb and trace elements contents in the Cordyceps sinensis samples from different sources. Stepwise discriminant analysis was used to select effective traceability indicators, and three discriminant models were successfully established. A combination of Co, Sr, Cu, Tl, and Zr indexes was selected to distinguish the naturally grown samples from the artificially cultivated ones, with an overall cross-validation correctness rate of 90.0 %; while a combination of As, Cu, Rb, Tl, W, and Zr indexes was adopted to distinguish the naturally grown samples from different regions, with a corresponding 100.0 % overall cross-validation correctness rate. To simultaneously distinguish samples between natural and artificial and between different regions, a combination of As, Cu, Rb, Tl, U, W, and δ15N indexes was employed, with an overall cross-validation correctness rate of 89.3 %.

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.

Concentrations, Speciation, and Potential Release of Hazardous Heavy Metals from the Solid Combustion Residues of Coal-Fired Power Plants.

Hazardous heavy metal-laden coal combustion byproducts exposed to precipitation or surface/groundwater are of environmental concern. This study analyzed fly ash (FA) and desulfurization gypsum (FGD gypsum) samples obtained from 16 coal-fired power plants in Guizhou Province, China. A combination of field and laboratory studies was used to investigate the binding forms of lead (Pb), cadmium (Cd), and chromium (Cr) and their leaching characteristics under natural storage conditions. The results showed that there were significant proportions of residual states of these elements in FA (84-99% for Pb, 83-91% for Cd, and 73-97% for Cr), indicating a lack of migration to other environmental media. FGD gypsum contained high proportions of metals in migratable states, but the environmental risks were low due to their very low concentrations. The release of Pb, Cd, and Cr from FA and FGD gypsum into extracts varied according to pH. This is related to the form of each element in the solid and the series of reactions that occurs during the leaching process. However, aside from Cr in FA, all heavy metals in FA and FGD gypsum samples were present in concentrations below the relevant standards for landfill leachate, indicating very low release rates. The Cr levels (206-273 µg/L) in some of the FA extracts were higher than the limits for water pollution from domestic landfill, indicating that Cr in FA poses a leaching risk. The results of field leachate sampling and indoor simulated rainfall experiments further validated these findings, indicating that the release of Cr from stockpiled coal FA is a cause for concern.

Effects of hydrological connectivity project on heavy metals in Wuhan urban lakes on the time scale.

Metal pollution in lakes threatens the ecological environment and human health. When environmental conditions change, heavy metals (HMs) in lake sediments can cause secondary pollution. At present, the implementation of the Hydrological Connectivity Project (HCP) is a significant means of lake governance. In this study, the accumulation, potential ecological risk, and sources of HMs in Four lakes (Houguan Lake, Tangxun Lake, Moshui Lake, and Chen Lake) in Wuhan city were compared before and after the completion of the HCP. The results indicated that the HCP reduced the enrichment factor of HMs and the potential ecological risk in the heavily polluted Moshui Lake but caused secondary pollution in the less polluted Houguan Lake. Moreover, the degree of purification of lakes that took a longer time to complete the HCP (Moshui Lake) was significantly higher than that of lakes with a shorter HCP completion time (Tangxun Lake). Water exchange caused by the HCP leading to exchange of the primary pollution source between Houguan Lake and Moshui Lake to a certain extent. This study provides a reference for evaluating the implementation effect of the HCP on HM pollution in lakes and for future governance planning.

Inputs and sources of Pb and other metals in urban area in the post leaded gasoline era.

The contamination status of heavy metals in urban environment changes frequently with the industrial structure adjustment, energy conservation and emission reduction and thus requires timely investigation. Based on enrichment factor, multivariate statistical analysis and isotope fingerprinting, we assessed comprehensively the inputs and sources of heavy metals in different samples from an urban area that was less impacted by leaded gasoline exhaust. The road dust contained relatively high levels of Cr, Pb and Zn (with enrichment factor >2) that originated from both exhaust and non-exhaust traffic emissions, while the moss plants could accumulate high levels of Pb and Zn from the deposition of traffic exhaust emission. This suggest that the traffic emission is still an important source of metals in the urban area although gasoline is currently lead free. On the contrary, the occurrences of metals in the urban soils were controlled by natural sources and non-traffic anthropogenic emission. These findings revealed that different samples would receive different inputs of metals from different sources in the urban area, and the responsiveness and sensitiveness of these urban samples to metal inputs can be ranked as moss ≥ dust > soil. Taken together, our results suggested that in order to avoid generalizing and get detail source information, multi-samples and multi-measures must be adopted in the assessment of integrated urban environmental quality.

Pine needles as urban atmospheric pollution indicators: Heavy metal concentrations and Pb isotopic source identification.

Pine needles are reliable passive bio-samplers that can be used to monitor atmospheric pollution levels. This study applied Pb isotope and multivariate statistical analyses to pine needles to examine the characteristics, sources, and ecological risks of atmospheric heavy metal pollution in the cities of the middle reaches of the Yangtze River, China. The heavy metal concentrations were higher than those measured in pine needles elsewhere in the world. They were higher in the metropolitan city (Wuhan) than in the medium-sized city (Yichang) and lowest in the natural setting (Shennongjia Forestry District), which is consistent with trends in urbanization and industrialization. Principal component analysis grouped the metals into three main sets associated with industrial activities and traffic sources. The Pb composition determined the main anthropogenic Pb sources were vehicle exhaust and industrial activities related to the lead-zinc ore, only a few of which were coal combustion. Three risk assessment indexes (pollution load index, ecological risk index, and bioconcentration factor) suggest that atmospheric heavy metals in the study area pose moderate environmental and health risks.

Effect of particle size on the colonization of biofilms and the potential of biofilm-covered microplastics as metal carriers.

Upon release into the aquatic environment, the surface of microplastics (MPs) can be readily colonized by biofilms, which may enhance the adsorption of contaminants. In this study, industrial-grade polystyrene (PS) of about 4 mm in size (MP4000-1), food-grade PS of about 4 mm in size (MP4000-2), and Powder PS of about 75 µm in size (MP75) were co-cultured with a model freshwater fungus, namely Acremonium strictum strain KR21-2, for seven days to form biofilms on their surface. We also determined the changes in surface physicochemical properties of the biofilm-covered MPs (BMPs) and the heavy metal adsorption capacity of the original MPs and BMPs. The results revealed that the biofilms improve the adsorption of heavy metals on MPs, and the particle size of MPs plays a crucial role in biofilm colonization and adsorption of heavy metals by BMPs. MP75 can carry more biofilm on its surface than that of the two MP4000s and form heteroaggregates with biofilms. In addition, there were more functional groups on the surface of BMP75 than on the surface of the two BMP4000s, which could promote the electrostatic interaction and chemical association of heavy metals. Moreover, BMP75 exhibited a higher capacity to adsorb Cu and reduce Cr (VI), which may be related to the functional groups in its biofilm. Overall, this study showed that after biofilms colonization, BMPs of smaller size have more significant potential as a metal vector, and the particle size deserves more scientific attention during the risk assessment.

Psychological Capital, College Adaptation, and Internet Addiction: An Analysis Based on Moderated Mediation Model.

Using data from a baseline survey of college students, this study examined the possible mechanism by which psychological capital influences college students' internet addiction through the mediation effect of their individual college adaptability. The study constructed a parallel multiple mediation effect model to help understand the effect mechanisms among these factors. The results indicated that psychological capital had a triple effect on internet addiction: (1) Psychological capital had a direct effect of helping reduce college students' internet addiction; (2) emotional, learning, and interpersonal adaptation not only reduced internet addiction directly but also played mediating roles in the relationship between psychological capital and internet addiction; and (3) the mediation effects of emotional and interpersonal adaptation were moderated by psychological capital, leading to two different modes of mediation effects. As a whole, psychological capital imposes a quadratic effect on internet addiction. The campus policy implications of these findings are discussed.

Heavy Metal in Rice and Vegetable and Human Exposure near a Large Pb/Zn Smelter in Central China.

Non-ferrous metal smelting is a significant source of anthropogenic heavy metal emission and has led to severe environmental pollution that ultimately threatens the health of local residents. In this study, we determined concentrations of copper (Cu), zinc (Zn), cadmium (Cd) and lead (Pb), as well as Pb isotopic compositions in rice, vegetables and human hair in areas surrounding the Zhuzhou Pb/Zn smelter in Hunan, China and we assessed the health risks associated with rice and vegetable consumption for local residents. Results showed that rice and vegetable samples were significantly contaminated by Cd and Pb. Age and source of rice were important factors for the enrichment of heavy metal concentrations in human hair. The ratios of Pb isotopes in human hair (1.164-1.170 for 206Pb/207Pb and 2.102-2.110 for208Pb/206Pb) were comparable to those in rice (1.162-1.172 for 206Pb/207Pb and 2.098-2.114 for208Pb/206Pb) and were slightly lower than those in vegetables (1.168-1.172 for 206Pb/207Pb and 2.109-2.111 for208Pb/206Pb), indicating that Pb in human hair mainly originated from food ingestion. A non-carcinogenic risk assessment showed that Cd exposure was the dominant health risk for local residents. This study suggested that crops planted surrounding the smelter were seriously contaminated with Cd and human exposure was related to dietary intake.

Health lifestyles and Chinese oldest-old's subjective well-being-evidence from a latent class analysis.

BACKGROUND: Previous research on the associations between lifestyle behaviors and health has largely focused on morbidity, mortality and disease prevention. More attention should be paid to examining relationships between lifestyle behaviors and positive health outcomes such as well-being. The aim of the study was to classify Chinese oldest-old's health lifestyles and evaluate the manner in which health lifestyles have impacted Chinese oldest-old's subjective well-being. METHODS: Analyzing the 2014 Chinese Longitudinal Healthy Longevity Survey (CLHLS), latent class analysis was applied to identify predominant health lifestyles among Chinese oldest-old aged 85 to 105. Ordinary Least Square (OLS) regression models were used to assess the effects of health lifestyles on Chinese oldest-old's subjective well-being, adjusting for socio-demographic characteristics. RESULTS: Four distinct classes representing health lifestyles emerged. Health lifestyles were found to be strongly associated with Chinese oldest-old's subjective well-being, even after controlling for demographic features as well as individual and parental socioeconomic disadvantage. Findings showed that healthy lifestyle behaviors stimulated Chinese oldest-old's positive feelings and led to better evaluative subjective well-being. In contrast, less healthy lifestyle behaviors can be a predictor of negative feelings. CONCLUSIONS: The regression results highlighted the importance of integrating health lifestyle choices in promoting oldest-old's psychological well-being. Elders can tackle healthier lifestyle behaviors in their daily lives to reduce the risk of mental health problems. Practicing healthy lifestyles should be integrated in programs for mental health promotion.

Heavy metal pollution caused by cyanide gold leaching: a case study of gold tailings in central China.

It is known that the tailings of gold mines have brought serious heavy metal pollution; however, the heavy metal pollution caused by gold tailings in specific geological environments and extraction processes still must be studied. This study investigated the distribution, speciation, bioaccumulation, and pollution of heavy metals in soils from the Yueliangbao gold tailings area in central China, where gold was extracted by cyanidation. The results show that the concentrations of Cu, Pb, Zn, Mn, Mo, and Cd in the soils of the tailings pond were higher than those in the local background. The concentrations of heavy metals related to mineralization activities, such as Cu, Pb, Zn, and Mo, varied with the distance to the tailings pond center. There was a decreasing trend of tailings pond center > tailings pond entrance > surrounding environment. This study's gold tailings pond differed from those of other regions because of its high content of unextracted Cu remaining in the pond. The proportion of non-residual Cu in the tailing pond soil was much higher than that of residual Cu, indicating it was likely to migrate to the surrounding environment. The pollution assessment indicated that the tailings pond soils were heavily polluted by Cu, and the level of heavy metal pollution in soils was positively correlated with the distance to the tailings pond center. Consequently, this tailings pond may become a source of Cu pollution in the surrounding environment, thus endangering environmental safety and human health. The study of heavy metal concentrations in the dominant plants showed that Chinese brake (Pteris vittata L.), Ramose scouring rush (Equisetum ramosissimum), and Manyflower silvergrass (Miscanthus floridulus) had the potential to be used for the phytostabilization of Cu.

Heavy Metal(loid)s Contamination in Ground Dust and Associated Health Risks at a Former Indigenous Zinc Smelting Area.

Indigenous zinc smelting (IZS) is a backward technique that releases a great deal of heavy metal(loid)s into the environment. However, the contamination of heavy metal(loid)s in ground dust and the associated health risks in such areas are poorly known. In this study, a former IZS area in Guizhou, China, was surveyed during 2008-2018 with 15 elements (Ag, As, Bi, Cd, Co, Cr, Cu, Hg, In, Ni, Pb, Sb, Sn, Tl, Zn) being analyzed. The results indicate that most elements (e.g., Ag, As, Cd, Cu, Pb, Sb, Sn, Zn) in ground dust decreased significantly after the cessation of the IZS in 2006; nevertheless, some elements still remained at relatively high levels in 2018, e.g., Pb (average: 762 ± 647 mg/kg), Zn (average: 1287 ± 753 mg/kg), Cd (average: 7.76 ± 5.06 mg/kg), and As (average: 41.9 ± 34.8 mg/kg), indicating they might come from the local contaminated soils, slag residues and smelting potteries. In terms of the impacts on human health, children have both higher non-carcinogenic and carcinogenic risks than that of adults, with the latter subpopulation having a lower risk than the threshold values. Pb and As were the two elements with the highest non-carcinogenic risk for children, the hazard index of local children was still higher than the threshold of 1 (e.g., 1.43 for As, 2.09 for Pb) in 2018. The carcinogenic risk of As exposure to children dropped more than two times to 6.42 × 10-7 in 2018, which falls below the tolerable range (10-6-10-4). This study revealed that although the concentration of heavy metal(loid)s in ground dust and linked health risk in the IZS area has reduced dramatically after the cessation of IZS, continued removal of slag residues and smelting potteries is necessary for further decreasing the human health risk.

Partitioning behaviors of zinc in eight coal-fired power plants with different fueled coals and air pollution control devices.

Emissions from coal-fired power plants (CFPPs) have a negative impact on the environment and metals are one of the categories of substances that have received considerable attention. In the present study, atmospheric zinc (Zn) emissions from eight CFPPs with different kinds of boilers and air pollution control devices (APCDs) in Guizhou Province, Southwest China, were investigated as well as the partitioning of this metal among boilers and APCDs. During the investigation of a CFPP, samples were taken of input and output materials during the same period. Our results give a Zn content of 32-165 mg kg-1 for feed coal, 52-237 mg kg-1 for bottom ash, 108-725 mg kg-1 for fly ash, 1.2-6.0 mg kg-1 for limestone, 1.6-7.3 mg kg-1 for gypsum, and 1.39-7.06 µg Nm-3 for stack gas. Most of the zinc content in the feed coal goes with the flue gas after combustion and amounts to 94.2-96.1% and 60.5-78.1% for pulverized coal-fired boilers (PC) and circulating fluidized bed boilers (CFB), respectively. Based on input Zn, a larger share (80.8-96.4%) ends up the captured fly ash of PC boilers than the case of CFB boilers (66.1-73.6%). In turn, a minor portion is captured into the flue gas desulfurization gypsum, while we found a maximum of 0.05‰ is emitted into the atmosphere. The atmospheric emission factors (EMFs) of Zn for the eight CFPPs are 7.55-57.22 mg ton-1 coal, 4.17-22.75 µg (kWh)-1, or 0.39-2.36 g TJ-1 using different benchmarks. Overall, the calculated emission factors here are distinctively low with the upgrading of APCDs in recent years. An estimation of 1276 ± 1047 kg year-1 (range: 498-3777 kg year-1) of Zn is emitted into the atmosphere from the CFPPs of Guizhou Province in 2017 by coupling the EMFs obtained from this study and the coal consumption by this category of power plants.

Geochemical cycle of mercury associated with wet deposition and inflows in a subalpine wetland.

Subalpine wetland is a mercury (Hg) sensitive ecosystem, but there is poor understanding of Hg behavior in this typical wetland. Here, distribution and speciation of Hg in waters of a subalpine wetland (Dajiuhu) in China were investigated, and an initial model of the Hg geochemical cycle in the wetland was established based on Hg mass balance calculations. Concentrations of both total Hg (THg, 9.52 ± 6.61 ng L-1) and total methyl mercury (TMeHg, 0.34 ± 0.44 ng L-1) in the waters during the wet season were higher than in the dry season. The majority of THg was in dissolved form whereas most TMeHg was in particle form. The geochemical models suggested that, due to the wet deposition and surface runoff, the input of THg and TMeHg into the wetland in the wet season (222 and 2.74 g year-1, respectively) was higher than that in the dry season (57.9 and 1.15 g year-1, respectively). The output of THg and TMeHg from the wetland underground runoff in the wet season was estimated to be 154 and 2.51 g year-1, respectively, and in the dry season was 15.9 and 0.43 g year-1, respectively. Other losses of Hg were due to volatilization of Hg0 from the sediment water (30.5 and 12.5 g year-1 in the wet and dry seasons, respectively). The flux of the settling of particulate Hg in the wet season was higher than that in the dry season. The fluxes of Hg diffusion from the porewater were relatively low in comparison to the fluxes of inflows and wet deposition. The flux of oxidation was higher than reduction, while the flux of methylation was higher than demethylation. These results indicated that the elevated levels of THg and MeHg in the Dajiuhu wetland are a consequence of rainfall and surface runoff inputs.

Distribution patterns and sources of heavy metals in soils from an industry undeveloped city in Southern China.

The accumulations of heavy metals in urban soils are derived from natural parent materials and complex anthropogenic emission sources. This paper investigated metal contamination in urban soils at an industry undeveloped city (Haikou) in southern China, an ideal place to quantitatively assess the contribution of metals from different sources. The concentrations of most heavy metals in the urban soils of Haikou were much lower than their guideline values and that of those from other big cities in China. In contrast, the chemical speciation of metals in this study was similar to those from other cities. The spatial distributions of heavy metals and principal component analysis (PCA) revealed that basaltic parent materials, traffic emissions, and coal combustion were the main factors controlling the distribution of metals in the soils. The Pb isotope signatures of the Haikou soils were greatly different from those of the Beijing and Shanghai soils, but similar to those of the Guangzhou soils, suggesting the common sources of Pb in southern China cities. The results of ternary mixing model of Pb isotopes showed that the contributions of Pb from natural background, coal combustion and traffic emission sources were 5.3-82.4% (mean: 39.7 ± 21.1%), 0-85.7% (mean: 25.5 ± 24.6%), and 1.9-64% (mean: 34.8 ± 22.9%), respectively. This suggests that traffic emission is still the most important anthropogenic source of Pb in Haikou.

Effects of exogenous dissolved organic matter on the adsorption-desorption behaviors and bioavailabilities of Cd and Hg in a plant-soil system.

Dissolved organic matter (DOM) is one of the most active soil components and plays critical direct and indirect roles in heavy metal migration, transformation, bioavailability, and toxicity in soils. In this study, isothermal adsorption/desorption experiments and pot experiments were performed and samples were physically characterized to study the effects of different sources of DOM on adsorption and desorption behavior and bioavailability of Cd and Hg in a plant-soil system. The results showed that microbial DOM promoted Cd and Hg adsorption in soil and decreased Cd and Hg bioavailability to pak choi (Brassica chinensis Linn.). In contrast, straw DOM and farmyard manure DOM decreased Cd and Hg adsorption and improved Cd and Hg migration and bioavailability. These results might be explained by the different types of DOM having different molecular weights and degrees of aromaticity. Cd was more readily desorbed by the soil and was more phytoavailable than Hg. We concluded that exogenous microbial DOM can inhibit Cd and Hg migration and bioavailability in soil but straw DOM and farmyard manure DOM can activate Cd and Hg in soil and promote Cd and Hg accumulation in plants. The results could help in developing rational agricultural fertilization regimes.

Risks related to heavy metal pollution in urban construction dust fall of fast-developing Chinese cities.

Urban construction is a major contributor to air pollution, but few studies have examined heavy metal pollution in urban areas caused by construction dust fall. We measured the concentrations of Cr, Ni, Cu, Zn, Pb, Cd, and Hg and particle size distribution in dust fall from various construction activities in seven fast-developing cities in China and conducted a health risk assessment. Mean metal concentrations in construction dust fall were on the order of Zn (246.3 mg/kg) > Cr (94.2 mg/kg) > Pb (56.5 mg/kg) > Cu (53.6 mg/kg) > Ni (22.8 mg/kg) > Cd (0.68 mg/kg) > Hg (0.08 mg/kg). Cu and Zn were positively correlated in areas of subway and building construction, and Pb and Cd were positively correlated in areas of road construction, likely because of the materials specific to these activities. Enrichment factors for heavy metals at all sampling sites were on the order of Cd (10.4) > Zn (6.37) > Cu (4.25) > Pb (3.84) > Hg (2.41) > Cr (2.02) > Ni (1.32). The enrichment factors for all metals except Zn indicated that heavy metal pollution was highest in road construction, followed by building and subway construction. Non-carcinogenic risks to children (hazard index >1) were 1.01-1.08 in four of the seven sampling sites, indicating possible risk from deposition of construction dust fall. In contrast, the hazard index for adults was <1 at the seven cities and total carcinogenic risks (<1 × 10-6) were at acceptable levels. An integrated ecological risk assessment demonstrated that heavy metal particles in construction dust fall in two of the cities (Shijiazhuang and Qingdao) were likely to be suspended in the atmosphere. Our study of heavy metal pollution in construction dust fall provides data on ecological and human health impacts and suggests that extensive measures are required to control construction dust fall in China.

Levels, sources, isotope signatures, and health risks of mercury in street dust across China.

Spatial distribution and isotope signature of mercury (Hg) in street dusts across China were investigated by collecting dust samples from 14 cities and reviewing previously published data from an additional 46 cities. Potential sources of street dust and the associated health risks to humans were also assessed. The total Hg (THg) concentrations in street dust ranged from 0.020-39.1 mg kg-1 with an average of 0.433 ±â€¯0.185 mg kg-1 in the 60 cities. Street dust samples collected from 14 cities were characterized by slightly negative δ202Hg (-0.61 ±â€¯0.92‰) and near-zero Δ199Hg (-0.03 ±â€¯0.08‰) values, and coal combustion and industrial activities were estimated to be the major sources of Hg in street dust. The estimated average probable daily intake (PDI) of THg from street dust exposure for adults and children (1.36E-03 and 1.27E-02 µg d-1 kg-1, respectively) were comparable to their respective exposures via rice consumption in China. Children being exposed to THg in dust is a major concern in mercury mining areas (e.g., Wangshan and Xunyang), and may also be a concern in cities with major coal-based industries and nonferrous metal smelting. Results from this study suggest that exposure to street dust is not a primary MeHg exposure pathway in China.

Magnetic mineral constraint on lead isotope variations of coal fly ash and its implications for source discrimination.

Coal fly ash in the atmosphere affects air quality and potentially influences the global climate by promoting oceanic productivity. Although accurately tracing the sources of fly ashes is vital for emission control, it remains a challenging task. Stable lead (Pb) isotope analysis is a useful tool for tracing atmospheric pollution but it fails to accurately address coal combustion emissions due to the broad range of Pb isotopic composition of coal. Environmental magnetic parameters can be used as a rapid and economical proxy for tracing atmospheric pollutants (including coal fly ashes) and have the potential for discriminating emission sources. In this study, we combined magnetic parameters with Pb isotopic signatures in order to better discriminate the sources of coal fly ash. Both magnetic particles and Pb are highly concentrated in the fly ashes compared with the feed coals. Most of the fly ashes exhibit higher 206Pb/207Pb and lower 208Pb/206Pb ratios than those of the feed coals. Furthermore, the Pb isotopic compositions of the fly ashes are highly correlated (p < 0.01) with the concentrations of magnetic particles (especially hematite), suggesting that the variation of Pb isotopes in the fly ashes is controlled by the adsorption of Pb on magnetic minerals. Based on the established relationship between magnetic minerals and Pb isotopes within coal fly ashes, we re-analyzed previously reported magnetic and Pb isotopic data from atmospheric dust and demonstrated the effectiveness of the combined method in discriminating coal fly ash in the atmosphere.

Profiles, source identification and health risks of potentially toxic metals in pyrotechnic-related road dust during Chinese New Year.

Potentially toxic metal (PTM) pollution in road dust is of great concern, however, our understanding of PTMs released by pyrotechnic displays and their adverse impacts on human health in road dust is limited. Here, we studied PTM pollution levels and Pb isotope signatures in pyrotechnic ash and road dust (aged dust and pyrotechnic-influenced dust) samples from eight cities in China during Chinese New Year and carried out a human health risk assessment. Pyrotechnic ash had higher values of Cr, Co, Ni, Cu, Zn, As, Sr and Pb but lower values of Mn and Cd than Chinese background soil. Pyrotechnic-influenced dust had significantly higher Cu and Cr values than aged dust, with enrichment of Sr, Cu, Pb, Cr and Ni in road dust after pyrotechnic displays. Both 208Pb/206Pb and Sr values were used to confirm the presence of pyrotechnic ash in road dust. A positive matrix factorization demonstrated that pyrotechnic events contributed 70.1%, 50.4%, 36.6% and 35.5% of the Sr, Cu, Cr and Pb values to these road dust, respectively. We found that non-carcinogenic and carcinogenic risks related to PTMs in road dust were at safe levels during the Chinese New Year, although both risks were elevated following pyrotechnic events. Typically, PTM pollutants related to pyrotechnic events contributed 33.99% to non-carcinogenic and 21.83% to carcinogenic risks, suggesting that more attention needs to be paid to this source of PTM pollution in China. Current results improve our understanding of PTM pollution in pyrotechnic-influenced road dust and health risks related to pyrotechnic displays in China.