Exposure Assessment of Benzotriazole Ultraviolet Absorbers in Plastic Sports Field Dust and Indoor Dust: Are Plastic Sports Fields High Exposure Scenarios?

Benzotriazole ultraviolet absorbers (BUVs), as emerging contaminants of extensive use, especially in plastic sports fields, have aroused increasing concern due to their potential human and environmental impacts. However, BUV exposure from plastic sports field dust is still unknown. This study compared BUVs in plastic sports field dust and indoor dust for the first time. The order of the geometric mean concentrations of the total BUVs (ΣBUVs) in plastic sports field dust was indoor badminton courts (11023 ng g-1) > basketball courts (4777 ng g-1) > plastic tracks (3779 ng g-1) > synthetic turf (1920 ng g-1) > tennis courts (689 ng g-1). The geometric mean concentrations of ΣBUVs in indoor dust (1150 ng g-1) were lower than those in most plastic sports field dust. The dominant BUV was 2-hydroxy-4-(octyloxy)benzophenone (UV-531) in plastic sports field dust, while 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-2H-benzotriazole-2-yl)phenol] (UV-360) was the dominant BUV in indoor dust. Releases from plastic track materials, sneaker soles, and friction between them might be important BUV sources in plastic track dust. The average estimated daily intakes of ΣBUVs from plastic sports field dust for general exercisers were lower than those from indoor dust, but those for exercisers with long time or professional athletes might be higher, potentially posing health risks.

Spatial distributions, behaviors, and sources of PCDD/Fs in surface water and sediment from the Yangtze River Delta.

The Yangtze River Delta (YRD), one of the most economically developed and industrialized regions in China, is confronted with challenges arising from rapid urbanization, particularly environmental pollution. The collection of surface water and sediment samples from forty-nine sites in the YRD was conducted to analyze 2378-substituted polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) congeners. The detected concentrations of PCDD/Fs were 0-5.3 pg TEQ/L in water and 0.12-1493 pg TEQ/g dw in sediment. The PCDD/Fs contamination in the sediment was widespread in the YRD. There were variations in the congener characteristics of PCDD/Fs in surface water and sediment. The proportion of OCDD was significantly lower in surface water samples compared to sediment, while the less chlorine-substituted homologs were found in larger proportions. To understand the partitioning and behavior of dioxins within the water-sediment system, we calculated the organic carbon normalized partition coefficients and fugacity fraction (ff) of PCDD/F congeners. The results revealed that the PCDD/Fs had not attained a state of distributional equilibrium, and the non-specific hydrophobic effect seemed minimally influential on their partitioning between sediment and water. The average ff values, which varied between 0.06 and 0.63, indicated differing migration directions for the PCDD/F congeners. Source identification analysis provided evidence that the dioxins in the river water were primarily attributed to industrial thermal processes. Iron and steel smelting, along with pesticide production and use, were likely responsible for the sediment contamination. This comprehensive analysis underscores the complex nature of PCDD/Fs pollution in the YRD and highlights the necessity for targeted environmental management strategies.

Concentrations and distributions of fluorotelomer alcohols and perfluoroalkane sulfonamido substances in the atmosphere in the Pearl River Delta, China.

Per and polyfluoroalkyl substances (PFASs) have attracted major global concerns because some of them are environmentally persistent, bioaccumulative, and toxic. Perfluoroalkyl acids (PFAAs) have been well-characterized in water, soil, and sediment; however, fluorotelomer alcohols and perfluoroalkane sulfonamido substances have been overlooked. In this study, concentrations of three fluorotelomer alcohols and four perfluoroalkane sulfonamido substances were determined in the air at nine locations representing urban, rural-urban transect, and urban areas in the Pearl River Delta region, China to investigate their seasonal and spatial distributions and potential sources. At least two of the targeted PFASs were detected in all air samples in the Pearl River Delta region, with concentrations ranging from 371 pg/sampler to 18700 pg/sampler. Fluorotelomer alcohols were dominant compounds (contributing 46% to the ∑7PFAS concentration on average) in the atmosphere in the Pearl River Delta region. The total concentrations of the seven targeted PFASs were significantly higher in summer than in other seasons in urban areas. PFAS concentrations were positively related to the population density in the Pearl River Delta region. Local diffusive emission and long range transport could be sources of the seven PFASs in the air in the Pearl River Delta region.

Pollution level, spatial distribution, and congener fractionation characteristics of low-brominated polybrominated diphenyl ethers (PBDEs) in sediments around Chaohu Lake, China.

As new persistent organic compounds, polybrominated diphenyl ethers (PBDEs) have aroused important concern because of their potential bioaccumulation and possible ecological and health risk. To examine the sources and temporal variation of PBDEs in Chaohu Lake in eastern China, the surface sediments from Nanfei River (NFR) and core sediments from four estuaries were measured. It showed that low-brominated congeners were dominant, from MonoBDEs to HeptaBDEs (referred to as Σ39PBDE). Concentrations of ∑39PBDE and the ratios of (BDE-47 + BDE-99 + BDE-100)/(BDE-153 + BDE-154) were much greater in surface sediments than in core sediments. The highest concentration was observed in a site close to the outfall of a municipal sewage treatment plant (MSTP), and the ratio was significantly correlated with ∑39PBDE. These results suggested that PentaBDE and OctaBDE commercial mixtures were widely used around Chaohu Lake and the effluent of municipal sewage was a dominant source of PBDEs to surface sediment. Compared to data from other freshwater systems around the world, the concentrations of BDE-47 and BDE-99 in this study were in the middle of the range of global data, but BDE-183 concentrations were at the high end of the range. Due to restrictions on the usage of PentanBDE and OctaBDE commercial mixtures, reductions of PBDE levels from subsurface to superficial layer were observed in all estuaries. Elevated contribution by MonoBDEs to ∑39PBDE in the estuary of the only outflow river suggests significant congener fractionation. TriBDEs, TetraBDEs, and HexaBDEs appeared to pose low risks in all surface sediments, but moderate to high risks may be expected for PentaBDEs. Overall, the results would contribute to a better understanding of the sources and environmental fate of PBDEs in the studied eutrophicated lake.

Investigating the spatial distribution of polychlorinated biphenyls in sediment in the Pearl River Delta, South China.

One hundred forty-three surface sediment (0-5 cm depth) samples were collected from locations representing industrialized areas, less-industrialized areas, and e-waste recycling areas in the Pearl River Delta (PRD). The spatial distribution of polychlorinated biphenyls (PCBs) and their potential adverse effects on aquatic organisms were investigated. The average PCB concentration in the less-industrialized areas (background) in the PRD was approximately 10 ng/g dry weight (dw), which was generally half that found in the industrialized areas (approximately 22 ng/g dw). Severe PCB contamination, with concentrations ranging from 1000 to 26500 ng/g dw, was found in pond sediments collected from e-waste recycling areas. It is very likely that such contamination would have had adverse effects on the aquatic biota there. PCBs in the e-waste recycling areas were dominated by penta- and hex-PCB congeners, which made them significantly different from those found in other regions, where tri- and tetra-PCB congeners were predominant. Higher abundances of less chlorinated congeners were seen in the less-industrialized areas compared to the industrialized areas. Differences in the transport abilities of different congeners, together with dechlorination of higher chlorinated congeners, is the most likely reasons for this.

Contamination profiles and risk assessment of per- and polyfluoroalkyl substances in groundwater in China.

Per- and polyfluoroalkyl substances (PFASs) have attracted attention due to the potential risk they pose to ecosystems and human health. A total of 169 groundwater samples were collected from four representative regions in order to analyze PFASs concentrations in China. The total concentration of PFASs (∑PFASs) in groundwater ranged from 0.05 to 198.80 ng L-1, with an average of 3.97 ng L-1. All targeted PFASs were detected in the studied areas. The detection frequency and average concentration of perfluorooctanoic acid (PFOA) were the highest (79.29% and 1.61 ng L-1, respectively). The contamination profiles of PFASs in each study area varied due to natural geographical conditions and human activities. According to the results of the potential source identification, the point sources of perfluorooctane sulfonate (PFOS) were mainly concentrated in Lanzhou, and the distribution of PFASs was slightly affected by atmospheric deposition in all the studied areas. The obtained concentrations of PFOA and PFOS may pose no threat to the residents due to water consumption.

Persistent halogenated compounds in fish from rivers in the Pearl River Delta, South China: Geographical pattern and implications for anthropogenic effects on the environment.

Three fish species, mud carp (Cirrhinus molitorella), tilapia (Tilapia nilotica), and plecostomus (Hypostomus plecostomus), from rivers in the Pearl River Delta (PRD) were analyzed for dichlorodiphenyltrichloroethane and its metabolites (DDTs), hexachlorocyclohexanes (HCHs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), decabromodiphenyl ethane (DBDPE), and Dechlorane Plus (DP). The concentrations of DDTs, HCHs, PCBs, PBDEs, DBDPE, and DP ranged from 380-57,000, 5.5-100, 30-4200, 6.9-690, 0.29-460, and 0.09-20ng/g lipid weight, respectively. Congener profiles or chemical compositions of PBDEs, DPs, DDTs, and HCHs in plecostomus differed significantly from those in the other two fish species, which can be ascribed to species-specific metabolism. DDTs derived from historical residue and land erosion remained the predominant pollutants in the PRD, while industrial and urban activities resulted in elevated levels of PCBs and PBDEs in the metropolitan area. E-waste recycling activities have greatly impacted on the adjacent aquatic environment, and the potential point source for DBDPE was also revealed.

Atmospheric mercury species at Nam Co (4730 m a.s.l.), a highland background site in the inland Tibetan Plateau: implications of mercury potential sources.

A field survey was conducted in the central Tibetan Plateau (Nam Co) in China for high-time resolution measurements of gaseous elemental mercury (GEM), gaseous oxidized mercury (GOM), and particle-bound mercury (PBM). Average concentrations (± 1 SD) of GEM, PBM, and GOM from November 2014 to March 2015 were 1.11 ± 0.20 ng m-3, 50.8 ± 26.5 pg m-3, and 3.6 ± 3.2 pg m-3, respectively. During the monitoring period, both GEM and GOM exhibited relative stability in their monthly variations, whereas PBM concentrations were significantly higher in winter compared to those in later autumn and early spring. In terms of diurnal variations, the maximum concentration of GEM was typically observed after sunrise, while PBM reached its peak before sunrise, and the highest concentration of GOM was recorded in the afternoon. Vertical convection conditions, photochemical production, and gas-particle partitioning were responsible for the diurnal cycle of atmospheric mercury. Based on modeling results, it was determined that the air mass transported from South Asia significantly impacted atmospheric mercury levels at Nam Co Station. The regions of western and central Nepal, central and eastern Pakistan, and northern India were identified as potential sources of atmospheric mercury at Nam Co.

Microplastics in glaciers of Tibetan Plateau: Characteristics and potential sources.

Microplastics (MPs) in glaciers of remote areas are a hot topic linking the global transport of atmospheric MPs. The Tibetan Plateau (TP) holds large volume of glaciers, providing an effective way to trace MPs transport. Moreover, MPs in glaciers may have adverse effects on the local ecosystem and human health. In this study, we investigate MPs in snowpits collected from six glaciers across the different domain of the TP. The average abundance of MPs in six snowpits is 339.22 ± 51.85 items L-1 (with size ≥10 µm) measured by Agilent 8700 Laser Direct Infrared Chemical Imaging System (LDIR), represented by relatively high MPs abundance in the southern TP and low in the northern TP. The polymers with lower density, namely polyethylene (PE), polyamide (PA), and rubber, are the main MPs types, which are predominated by fragments with sizes smaller than 100 µm in each snowpit. Sources of MPs on glaciers include local tourism and vehicle traffic emissions of MPs. Meanwhile, long-range atmospheric transport of MPs from surrounded regions cannot be ignored. Backward trajectory analysis indicates cross-boundary transport of atmospheric MPs from South Asia play an important role on MPs deposited onto TP glaciers. Analysis further reveals that MPs in glaciers are associated with atmospheric mineral dust deposition. This study provides new data for the investigation of MPs in glaciers of remote areas, and a reference for studying MPs in the ice cores of TP glaciers.

Characteristics, sources, and health risk assessment of atmospheric particulate mercury in Guanzhong Basin.

Mercury (Hg) has received increasing public attention owing to its high toxicity and global distribution capability via long-range atmospheric transportation. Guanzhong Basin (GB) is vital for the industrial and economic development of Shaanxi Province. To determine the concentration, spatial distribution, seasonal variation, sources, and health risks of particulate-bound mercury (PBM), PM2.5 samples were collected at three sampling sites representing urban, rural, and remote areas during winter and summer in GB. The three sampling sites were in Xi'an (XN), Taibai (TB), and the Qinling Mountains (QL). The mean PBM concentrations in XN, TB, and QL in winter were 130 ± 115 pg m-3, 57.5 ± 47.3 pg m-3, and 53.6 ± 38.5 pg m-3, respectively, higher than in summer (13.7 ± 7.11 pg m-3, 8.01 ± 2.86 pg m-3, and 7.75 ± 2.85 pg m-3, respectively). PBM concentrations are affected by precipitation, meteorological conditions (temperature and mixed boundary layer), emission sources, and atmospheric transport. During the sampling period, the PBM dry deposition in XN, TB, and QL was 1.90 µg m-2 (2 months), 0.835 µg m-2 (2 months), and 0.787 µg m-2 (2 months), respectively, lower than the range reported in national megacities. According to backward trajectory and potential source contribution factor (PSCF) analysis, mercury pollution in XN is mainly affected by local pollution source emissions, whereas the polluted air mass in TB and QL originates from local anthropogenic emissions and long-distance atmospheric transmission. The non-carcinogenic health risk values of PBM in XN, TB, and QL in winter and summer were less than 1, indicating that the risk of atmospheric PBM to the health of the residents was negligible.

Pollution Characteristics and Health Risks of Polycyclic Aromatic Compounds (PACs) in Soils of a Coking Plant.

Coke production is an important source of environmental polycyclic aromatic compounds (PACs), including parent polycyclic aromatic hydrocarbons (PAHs) and their derivatives. The focus near coking plants has primarily been on parent-PAH contamination, with less attention given to highly toxic derivatives. In this study, soil samples were collected from both within and outside of a coking plant. The concentrations of parent-PAHs and their derivatives, including methylated-PAHs, oxygenated-PAHs, and nitrated-PAHs, were examined. Spatial interpolation was employed to determine their spatial distribution patterns. Methods for identifying potential sources and conducting incremental lifetime cancer risk analysis were used. This could achieve a comprehensive understanding of the status of PAC pollution and the associated health risks caused by coke production. The concentrations of total PACs inside the plant ranged from 7.4 to 115.8 mg/kg, higher than those outside (in the range of 0.2 to 65.7 mg/kg). The spatial distribution of parent-PAH concentration and their derivatives consistently decreased with increasing distance from the plant. A significant positive correlation (p < 0.05) among parent-PAHs and their derivatives was observed, indicating relatively consistent sources. Based on diagnostic ratios, the potential emission sources of soil PACs could be attributed to coal combustion and vehicle emissions, while principal component analysis-multiple linear regression further indicated that primary emissions and secondary formation jointly influenced the PAC content, accounting for 60.4% and 39.6%, respectively. The exposure risk of soil PACs was dominated by 16 priority control PAHs; the non-priority PAHs' contribution to the exposure risk was only 6.4%.

Regional differences in molecular characteristics of atmospheric water-soluble organic carbon over northern China: Comparison of remote, rural, and urban environments.

Atmospheric water-soluble organic carbon (WSOC) is a critical component of airborne particulates. It significantly affects the Earth's energy balance, air quality, and human health. Despite its importance, the molecular composition and sources of WSOC remain unclear, particularly in non-urban areas. In this study, we collected total suspended particulate (TSP) samples from three sites in northern China: Erenhot (remote site), Zhangbei (rural site), and Jinan (urban site). The WSOC components were analyzed using high-performance liquid chromatography coupled with high-resolution mass spectrometry. The results showed that the formula numbers of identified compounds exhibited a decreasing trend of Jinan (2647) > Zhangbei (2046) > Erenhot (1399). Among the assigned formulas, CHO compounds were the most abundant category for all three sites, accounting for 33 %-38 % of the identified compounds, followed by the CHON compounds with contributions of 27 %-30 %. In the remote site of Erenhot, CHO compounds were dominated by oxidized unsaturated organic compounds, and CHON compounds were mainly low-oxygenated aliphatic compounds, suggesting a significant influence of primary emissions. In contrast, the urban site of Jinan showed higher contributions of CHO and CHON compounds with elevated oxidation degrees, indicating the influence of more extensive secondary oxidation processes. Atmospheric WSOC in Erenhot and Zhangbei had abundant reduced sulfur-containing species, likely from coal or diesel combustion, while that in Jinan was characterized by aliphatic organosulfates and nitrooxy-organosulfates, which are mainly associated with traffic emissions and biogenetic sources, respectively. These findings reveal significant differences in the molecular composition of WSOC in different atmospheric environments and improve our understanding of the chemical properties, potential sources, and transformations of organic aerosols.

Spatial and temporal variability and risk assessment of organophosphate esters in seawater and sediments of the Yangtze River estuary.

Organophosphate esters (OPEs) as substitutes for PBDEs have been widely detected in the marine environment, while little is known about the pollution characteristics and variation of OPEs in estuarine environments with complex hydrodynamic conditions and land-based input. Yangtze River Estuary (YRE) is a typical highly urbanized and industrialized estuary, with a complex hydrological environment and geochemical behavior. This study found that the concentrations of OPEs in both seawater and sediments in the YRE were higher in spring than in summer. Alkyl OPEs were the first contributor, with TnBP and TiBP as the main components, where the contribution of alkyl OPEs had exceeded 75 % in both seawater and sediments in spring, and 60 % in summer seawater, and even 80 % in sediments. In spring, OPEs peaked in the central to southern region near the YRE. In summer, OPEs were mainly concentrated in the southern branch waterway and southern nearshore area of the YRE and showed a decreasing trend to the northeast. The OPEs in the sediments were mainly concentrated in the Yangtze River Mud Area (YREMA) and the Zhe-Min Coastal Mud Area (ZMCMA). Based on the fugacity model and principal component analysis, sediments could be released into the aquatic environment as an endogenous source, and exogenous sources were mainly municipal and industrial sewage discharge sources, urban and marine traffic discharge sources, and atmospheric deposition sources. The ecological risk analysis showed that the Σ14OPEs had exhibited a low to moderate ecological risk in the southern branch waterway and the south-central region offshore.

Vertical distributions and potential contamination assessment of seldom monitored trace elements in three different land use types of Yellow River Delta.

The Yellow River Delta (YRD) is the second largest petrochemical base in China and the impact of human activities has been continuously increasing in recent decades, however, the contamination status of seldom monitored trace elements (SMTEs) in YRD has rarely been reported. This study evaluated the levels, vertical distributions, contamination status and sources of SMTEs in soil samples of three different land use types in YRD. The results indicated that the vertical distributions of SMTEs contents showed a gradually upward increasing trend for the soil profiles of black locust forest, while the SMTEs contents displayed a gradually upward decreasing trend for the soil profiles of cotton field. However, the SMTEs contents in the oil field area showed no significant difference among different depths. The vertical distributions of SMTEs were very likely related to the anthropogenic disturbance in the later stage. The environmental pollution status assessment of SMTEs showed obvious enrichment of Cs, Sn, and U in the soils of YRD. Moreover, the potential source analysis based on multivariate statistical methods indicated that Ga, Rb, Cs, Sc, Sn, Tl, Be, Bi, Ca and Mo were clustered together and positively correlated with Al, Fe, Mg and K, and may be mainly associated with geochemical weathering process, while the Ce, La, Th, U, Nb, Ta, and Hf may be impacted by both natural process and human activities. Though the SMTEs pollution status was not very serious, our results highlighted the non-negligible influence of anthropogenic activities on vertical distributions of SMTEs in three different land use types from YRD. Our results provide valuable information for understanding the vertical distribution and pollution status of SMTEs in YRD.

[Meteorological Formation Mechanisms and Potential Sources of an Ozone Pollution Process in Winter of 2022 in Guangdong Province].

Meteorological conditions play an important role in seasonal ozone variations. In order to understand the meteorological formation mechanisms of ozone pollution in Guangdong Province in winter, the moderate ozone pollution process in Guangdong Province from January 3-6, 2022 was selected for comparison with that in autumn (high pollution season) of 2015 to 2021. The research was based on ground and vertical sounding data and reanalysis data of air quality and meteorological elements. Eight cities exceeded the standard during the pollution process, among which Zhaoqing showed moderate pollution (219 µg·m-3) on January 4th. The average O3-8h concentration in Guangdong Province was 123 µg·m-3, which was 21% higher than that in historical autumn. However, its scope of pollution was less than the historical pollution processes in autumn. Lower wind speed, longer sunshine hours, and airflow reflux effect under local circulation were the most important ground-level meteorological conditions for the ozone pollution process, whereas lower temperature might be an important reason for its small scope of pollution. Vertical detection analysis showed that the combined effect of low-level temperature inversion layer, stronger downdraft, and lower wind speed kept the NO2 concentrations at a high level, and further induced a higher increment of ozone concentration in the morning (34.2 µg·m-3 higher than that in the non-pollution period). The downward transport of ozone in the residual layer aggravated the ozone pollution on January 4th. The accumulation of ozone and its precursors was an important factor of the aggravation of ozone pollution the following day. Airflow trajectory analysis revealed that the ground-level ozone was affected by horizontal transport and vertical mixing of pollutants. Potential sources at 10 m were mainly distributed in the coastal areas from Fujian to Guangdong, and the scope of potential sources was concentrated in Guangdong as the height increased. Airflow backward trajectories at different heights during the ozone process passed over the areas of potential sources in Guangdong, which indicated that the local emissions in Guangdong had a greater impact on the ozone pollution process.

Organic ultraviolet absorbents in soils and typical plants from an industrial metropolis in China: Concentrations, profiles and environmental implications.

There is accumulating evidence of the toxicity of organic ultraviolet absorbers (OUVAs); however, limited information is available regarding the presence of OUVAs in terrestrial environments and organisms. Therefore, this study was conducted to investigate the occurrence of 11 OUVAs in soils and typical plant species from an industrial metropolis in China. Total OUVA concentrations in soils ranged from 1.30 to 80.3 ng g-1 DW. Based on comparison with previously reported data, OUVA contamination in soil was not severe. Benzophenone and octocrylene were the dominant OUVAs in soils, with median contributions to total concentrations of 25% and 15%, respectively. Source assessment revealed that the observed OUVA contamination primarily originated from industrial activities and the use of personal care products. The concentration of 11 OUVAs in plants ranged from 159 to 4470 ng g-1 DW, at high levels. Our findings imply that great attention should be given to the presence of these chemicals in plants because of the risk they could pose as well as the potential for biomagnification as plants are eaten by insects and birds. Our results also indicate the necessity to further study the geochemical behavior of these chemicals in urban ecosystems in order to better manage the harmfulness to terrestrial ecological health caused by their exposure through the food chains.

Characteristics and provenances of rare earth elements and Nd isotopes in surface sediments of mangrove wetlands in the Jiulong River Estuary, China.

Rare earth elements (REEs) and Nd isotopes are frequently employed to determine provenance, although their characteristics and provenances in the surface sediments of mangrove wetlands are rarely analyzed. In this study, a thorough analysis of the characteristics and provenances of REEs and Nd isotopes in the surface sediments of mangrove wetland in the Jiulong River Estuary was carried out. According to the results, the mean concentration of REEs in the surface sediments was 290.9 mg·kg-1, which was greater than the background value. Unpolluted to moderately polluted for La and Ce, as well as a moderate ecological risk for Lu, were indicated by the geoaccumulation index (Igeo) and potential ecological risk of individual factors ([Formula: see text]), respectively. The surface sediments showed substantial negative Eu anomalies but no significant Ce anomalies. The enrichments in LREE and flat HREE patterns are visible in the chondrite-normalized REE patterns. REEs in the surface sediments might be attributed to both natural sources (granite and magmatic rocks) and anthropogenic activities, including coal combustion, vehicle exhaust, steel smelting, and fertilizer, based on the (La/Yb)N-∑REE and ternary (La/Yb)N-(La/Sm)N-(Gd/Yb)N plots. The three-dimensional ∑LREE/∑HREE-Eu/Eu*-εNd(0) plot, when combined with the Nd isotope, further demonstrated that the REEs in the surface sediments appeared to have come from additional nonlocal potential sources.

Understanding heavy metal distribution in timberline vegetations: A case from the Gongga Mountain, eastern Tibetan Plateau.

To quantify impacts of vegetation and topographic factors on heavy metal accumulation in montane forests, we assessed the spatial distribution and determined the sources of mercury (Hg), cadmium (Cd), lead (Pb), chromium (Cr), copper (Cu) and zinc (Zn) in timberline forests of Gongga Mountain. Our results show that vegetation type has little impact on the soil Hg, Cd and Pb concentrations. The soil concentrations of Cr, Cu and Zn are controlled by litter return, moss and lichen biomass, and canopy interception, with the highest concentrations in shrub forest. In contrast to other forests, the soil Hg pool in coniferous forest is significantly high due to the elevated Hg concentration and greater biomass production in litter. However, the soil pool sizes of Cd, Cr, Cu and Zn show a distinct increase along the elevation, which are attributed to the elevated heavy metal inputs from litter and moss, as well as the greater cloud water-induced atmospheric heavy metal depositions. The highest Hg concentrations of the aboveground parts of plant are in the foliage and bark, while the concentrations of Cd, Pb, Cr, Cu and Zn in the branch and bark are the highest. The decreased biomass density leads to a downward trend in the total vegetation pool sizes of Hg, Cd, Pb, Cr, Cu and Zn by 0.4-4.4 times with increasing elevation. The statistical analysis finally suggests that Hg, Cd and Pb mainly originate from anthropogenic atmospheric deposition, whereas Cr, Cu and Zn are mainly from natural sources. Our results highlight the importance of vegetation types and terrain conditions on distribution patterns of heavy metal in alpine forests.

[Potential Source Identification and Ecological Risk Assessment of Heavy Metals in Surface Soil of Heze Oil Peony Planting Area Based on PMF-PCA/APCS and PERI].

To study the sources and potential risks of heavy metals in soils of characteristic agricultural product producing areas is of great significance for the scientific management and safe utilization of soil and crop resources. The contents of heavy metals As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn in the 254 surface soil samples collected from the Heze oil peony planting area were determined. The content characteristics and correlation of heavy metals were analyzed using multivariate statistical methods. The sources of heavy metals in topsoil were analyzed using Igeo, PMF, and PCA/APCS. The ecological risks of the eight heavy metals were assessed through the potential ecological risk index (PERI). The results showed that the average contents of seven heavy metals in the soil were basically consistent with the background values of soil elements in Heze City, except that the average value of Cd was 1.44 times higher than the background value in Heze City. Correlation analysis and cluster analysis revealed that Pb, Hg, and Cd elements in the soil were greatly affected by human activities in the later period. The sources of eight heavy metals in the study area were natural sources, agricultural fertilizer sources, industrial coal sources, and domestic transportation sources, with the contribution rates of 81.31%, 15.45%, 2.74%, and 0.50%, respectively; 84.25% of the sites in the study area were at slight ecological risk, whereas the moderate risk and strong risk sites accounted for 14.96% and 0.79%, respectively. Among them, Cd and Hg were the dominant elements of ecological risk in the study area.

PSCF and CWT methods as a tool to identify potential sources of 7Be and 210Pb aerosols in Granada, Spain.

This research is focused on studying the preferred source regions and the pathways of the air masses with high particulate concentrations impacting on the activity concentrations of 7Be and 210Pb aerosols in Granada atmosphere. For this purpose, three different source-receptor methods have been used: Cluster Analysis, Potential Source Contribution Function (PSCF), and Concentration Weighted Trajectory (CWT). Air filter samples were weekly collected and analysed in Granada university (Spain 37.177N, 3.598 W, 687m a.s.l.) during 12 years (2006-2017) for the activity concentration of 7Be, and during 5 years (2010-2014) for the one of 210Pb. The time series of the collected data indicate that the concentration of both radiotracers present a cyclical and seasonal pattern, in association with their origins and atmospheric conditions. Clustering analysis showed that the air masses arriving to Granada can be classified as: (1) tropical continental air masses coming from the Mediterranean Sea, (2) tropical and warm polar maritime air masses produced over the Atlantic Ocean, and (3) continental air masses originated over Europe and Northern Africa. The PSCF and CWT methods confirmed that the main source areas of 7Be are located in the Atlantic coast of southern Morocco, and Northern Africa. On the other hand, southern France and the Algerian desert were found to be the main region sources of 210Pb. In addition, the Mediterranean Basin has been postulated as a strong source region for 7Be and 210Pb. Furthermore, the PSCF and CWT models show that the regions with larger 7Be/210Pb ratios are located in the Atlantic Ocean, due to frequent stratospheric intrusions specially during the winter months.