Field Evidence for Asian Outflow and Fast Depletion of Total Gaseous Mercury in the Polluted Coastal Atmosphere.

Atmospheric mercury (Hg) cycling in polluted coastal atmosphere is complicated and not fully understood. Here, we present measurements of total gaseous mercury (TGM) monitored at a coastal mountaintop in Hong Kong downwind of mainland China. Sharp TGM peaks during cold front passages were frequently observed due to Asian pollution outflow with typical TGM/CO slopes of 6.8 ± 2.2 pg m-3 ppbv-1. Contrary to the daytime maximums of other air pollutants, TGM exhibited a distinct diurnal variation with a midday minimum. Moreover, we observed four cases of extremely fast TGM depletion after sunrise, during which TGM concentrations rapidly dipped to 0.3-0.6 ng m-3 accompanied by other pollutants on the rise. Simulated meteorological fields revealed that morning upslope flow transporting anthropogenically polluted but TGM-depleted air masses from the mixed layer caused morning TGM depletion at the mountaintop location. The TGM-depleted air masses were hypothesized to result mainly from fast photooxidation of Hg after sunrise with minor contributions from dry deposition (5.0%) and nocturnal oxidation (0.6%). A bromine-induced two-step oxidation mechanism involving abundant pollutants (NO2, O3, etc.) was estimated to play a dominant role, contributing 55%-60% of depleted TGM and requiring 0.20-0.26 pptv Br, an amount potentially available through sea salt aerosol debromination. Our findings suggest significant effects of the interaction between anthropogenic pollution and marine halogen chemistry on atmospheric Hg cycling in the coastal areas.

Atmospheric wet deposition of mercury in urban Jinan, eastern China: Speciation, scavenging process and potential sources.

Understanding the speciation and related influence factors of Hg in wet deposition is important to predict the fate and transport of mercury in the atmosphere. In this study, event-based samples of rainwater were collected for one year in Jinan, a northern city in eastern China. The volume-weighted mean concentration of total mercury (THg) in rainwater was 34.8 ng L-1, comparable to levels in some inland cities in China and were significantly higher than those in North America, Korea and Japan. Most of the Hg in rainwater was associated with particulates, accounted for 15.2-92.9% of THg with a mean of 66.9%, which might be attributed to the scavenging effects of high particulate-bound mercury concentrations in ambient air in urban Jinan. Dissolved mercury (DHg) accounted for 33.1% of THg, in which Hg(OH)2, HgClOH, HgCl2 and Hg(NH3)22+ are the dominant species based on the chemical equilibrium modeling simulations. THg concentrations in rainwater decreased as the rainfall amount increased owing to the dilution effect and 5 mm rainfall might be a threshold for the full wash-out capability of atmospheric Hg. For a continuous rain event, the proportion of DHg in THg could increase from 7.1% to 84.8% with the rainfall processing, especially for the species of HgClOH and HgCl2 under the influence of rainwater pH. Positive matrix factorization (PMF) analysis suggested that the major sources of Hg in rainwater were combustion emissions, marine sources, industrial emissions, as well as complexation process, which contributed to 51.4%, 24.7%, 12.2%, and 11.7% of the THg, respectively. For the specific species, the main sources varied with different Hg species, in which combustion emissions contributed one third to one half of each species sum to particulate mercury (PHg), HgClOH, HgCl2, HgBrOH and HgBrCl followed by marine sources and industrial emissions. Cluster analysis of backward trajectories revealed that polluted air masses, transported from southeast Shandong, Anhui and Jiangsu Provinces, as well as Beijing-Tianjin-Hebei region, contributed to high Hg concentration in rainwater in Jinan.

Atmospheric mercury in an eastern Chinese metropolis (Jinan).

Urban emissions are a major contributor to atmospheric Hg budgets. Continuous measurements of total gaseous mercury (TGM) and particulate-bound mercury (PHg) in PM2.5 were conducted from October 2015 to July 2016 in a metropolis, Jinan, in eastern China. Average TGM and PHg concentrations were 4.91 ± 3.66 ng m-3 and 451.9 ± 433.4 pg m-3, respectively, in the entire study period. During the winter heating period (HP), mean concentrations of TGM and PHg were 5.79 ng m-3 and 598.7 pg m-3, respectively, twice higher than those during the non-heating periods (NHPs). During the HP, TGM exhibited a distinct diurnal pattern with a peak in the morning and a minimum in the afternoon on less polluted days but a singular peak at midday on heavily polluted days. The diurnal variation of TGM during the NHPs was predominantly influenced by the variation in boundary layer height while during the HP by anthropogenic emissions. The ratio of PHg/PM2.5 in Jinan was one to two orders of magnitude larger than those elsewhere worldwide and those in soil and coal, which suggested the high enrichment of PHg in PM2.5 in Jinan. Correlation and principle component analysis results suggested that PHg and TGM had common combustion sources during the HP, whereas PHg resulted mainly from biomass burning and meteorological variations during the NHPs. High Hg concentrations in Jinan were mostly caused by emissions from coal-fired power plants, especially for those situated east of the sampling site. In addition, TGM and PHg concentrations significantly increased during haze and fog episodes, but decreased during a dust episode due possibly to strong ventilation conditions combined with partitioning of Hg between adsorption to PM2.5 and coarse dust particles.

SP94 Peptide-Functionalized PEG-PLGA Nanoparticle Loading with Cryptotanshinone for Targeting Therapy of Hepatocellular Carcinoma.

To achieve improved drug delivery efficiency to hepatocellular carcinoma (HCC), biodegradable poly (ethylene glycol)-poly (lactic-co-glycolic acid) (PEG-PLGA) nanoparticles (NP), surface-modified with SP94 peptide, were designed for the efficient delivery of cryptotanshinone to the tumor for the treatment of HCC. Cryptotanshinone NP and SP94-NP were prepared by using nanoprecipitation. The physicochemical and pharmaceutical properties of the NP and SP94-NP were characterized, and the release kinetics suggested that both NP and SP94-NP provided continuous, slow release of cryptotanshinone for 48 h. The in vitro cellular experiment demonstrated that SP94-NP significantly enhanced the cellular uptake of cryptotanshinone and induced high cytotoxicity and cellular apoptosis of hepatocellular carcinoma (HepG2) cells. The in vivo detecting results of targeting effect using the Cy5.5 probe evidenced that SP94-NP showed an accumulation in tumor more efficiently than that of unconjugated ones. Meanwhile, SP94-NP exhibited the smallest tumor size than other groups and showed no toxicity to body. The results of this study provide a promising nanoplatform for the targeting of HCC.

Insights on Chemistry of Mercury Species in Clouds over Northern China: Complexation and Adsorption.

Cloud effects on heterogeneous reactions of atmospheric mercury (Hg) are poorly understood due to limited knowledge of cloudwater Hg chemistry. Here we quantified Hg species in cloudwater at the summit of Mt. Tai in northern China. Total mercury (THg) and methylmercury (MeHg) in cloudwater were on average 70.5 and 0.15 ng L-1, respectively, and particulate Hg (PHg) contributed two-thirds of THg. Chemical equilibrium modeling simulations suggested that Hg complexes by dissolved organic matter (DOM) dominated dissolved Hg (DHg) speciation, which was highly pH dependent. Hg concentrations and speciation were altered by cloud processing, during which significant positive correlations of PHg and MeHg with cloud droplet number concentration ( Nd) were observed. Unlike direct contribution to PHg from cloud scavenging of aerosol particles, abiotic DHg methylation was the most likely source of MeHg. Hg adsorption coefficients Kad (5.9-362.7 L g-1) exhibited an inverse-power relationship with cloud residues content. Morphology analyses indicated that compared to mineral particles, fly ash particles could enhance Hg adsorption due to more abundant carbon binding sites on the surface. Severe particulate air pollution in northern China may bring substantial Hg into cloud droplets and impact atmospheric Hg geochemical cycling by aerosol-cloud interactions.

[Simultaneous determination of 6 cyclohexanedione herbicides residues in potatoes by ultra-performance liquid chromatography-tandem mass spectrometry].

OBJECTIVE: To establish a method for analysis of 6 cyclohexanedione herbicides residues in potatoes by ultra-performance liquid chromatography coupled with electrospray tandem mass spectrometry( UPLC-MS/MS). METHODS: The target compounds in samples were extracted ultrasonically with acetonitrile. After centrifugation, the supernatant was cleaned up with Envi-carb column. The sample solution was separated on an Dionex C_(18) column( 2. 1 mm × 100 mm, 2. 2 µm) with gradient elution using acetonitrile -5 mmol/L ammonium acetate and 0. 1% formic acid in water as mobile phase. The identification was performed with tandem mass spectrometer, with electrospray ionization( ESI) in positive mode under multiple reaction monitoring. The quantification was based on external standard curves. RESULTS: The method showed good linearity in the range of 2-100 µg/L( r ≥ 0. 9923). The limit of quantitation were 2. 0 µg/kg. The detection limits of the method were 0. 6 µg/kg. The recoveries were within 67. 5%-95. 8% at the spiked levels of 2. 0-10. 0 µg/kg, and the relative standard deviations were all less than 8. 5%. Six cyclohexanedione herbicides residues were detected in 6. 7% of 30 potatoes samples which was determined by the method. CONCLUSION: The method is rapid, specific, accurate, and it is suitable for detection of quinolone and tetracycline residues.

[Assessment on exposure of dietary aluminium among residents in Shaanxi Province during 2013-2015].

OBJECTIVE: To investigate the contamination condition of the aluminium in commercial foods in Shaanxi Province, and evaluate aluminium dietary intake level in Shaanxi population and its potential health risks. METHODS: 1331 samples in Shaanxi Province were collected from 2013 to 2015. The aluminium contents were detected by National Food Contamination and Harmful Factors in Risk Monitoring Manual, and data of total diet study in Shaanxi Province in 2007, to calculate dietary intake of aluminium in Shaanxi population. RESULTS: Average dietary intake of aluminium was 0. 358 mg/( kg·d), accounted for 125% of PTWI. The dietary intake of aluminium in children aged 2 to7 years old was highest, followed children aged 8 to 12 years old and men aged 13 to 19 years old. Grain products and potato products were the main sources of aluminium exposure compared with others. CONCLUSION: The dietary intake of aluminium in Shaanxi population is more than the PTWI. The children aged 2 to 7 years old, children aged 8 to12 years old and men aged 13 to 19 years old is high. Grain products and potato products are the main sources of aluminium exposure in Shaanxi population. The effective measureto control the intake of aluminium is to normalize and rationalize the use of additives containing aluminium.

[Dietary exposure and health risk assessment of heavy metal in grains of Shaanxi Province].

OBJECTIVE: To investigate heavy metal contamination of grains, and to assess the health risk of the contamination on local inhabitants. METHODS: The contents of 6 heavy metals of grains were detected, according to the food contamination monitor plan of Shaanxi Province. The levels of heavy metal contamination on grains were evaluated by pollution indices. Health risks associated with the daily dietary intake of heavy metals were assessed using USEPA health risk assessment model. RESULTS: 562 grain samples were randomly collected from 94 representative sites in Shaanxi Province. The contaminations of Cd and Pb were more seriously than the other metals. The pollution indices of Cd, As, Cr, Hg, Ni and Pb in 4 kinds of grains were less than 0.7, they were safe to eat. The dietary expose doses of Cd, As, Cr, Hg, Ni and Pb were also at the level of safety. The individual health risk of heavy metal pollution was 3.08 x 10(-4)/year for Cr, which was exceed the standard (5.0 x 10(-5)/year) of Inernational Commission on Radiological Protection (ICRP). The individual health risks of the other five metals were lower than the standard of ICRP. CONCLUSION: The most of grains are considered safe to eat for consumers, excepting a few samples are polluted by lead and cadmium. The individual health risk of Cr is higher than the standand of ICRP.

[Survey and evaluation of heavy metal in the major vegetables in Shaanxi Province].

OBJECTIVE: To evaluate the contamination condition of the Pb, Cd, Hg and As in ten kinds of vegetables in Shaanxi Province. METHODS: The Pb and Cd contents were determined by inductively coupled plasma mass spectrometry, and the As contents were determined by hydride generation-atomic fluorescence spectrometry, and the Hg contents were determined by mercury vapourmeter. One factor contamination index was employed to evaluate the metal pollution situation of different types of vegetables. Moreover, the health risk after intake of those heavy metals through vegetables were described. RESULTS: In ten kinds of vegetables of Shaanxi Province, the Pb contents in cowpea reached the alertness level, while the contents of Cd, Hg and As were below the safety level. What' s more, the contents of the Pb, Cd, Hg and As were below the safety level in other nine vegetables, and the over standard rate of were Hg > Pb > Cd > As. CONCLUSION: The contamination extents of Pb, Cd, Hg and As in ten kinds of vegetables in Shaanxi Province were low.

[Investigation on contamination situation of malachite green in freshwater fish and its dietary exposure assessment of Shaanxi Province].

OBJECTIVE: To investigate the residue levels of malachite green (MG) in freshwater fish and assess the dietary MG exposure of Shaanxi residents. The second aim was to assess the health risk of intaking MG from freshwater fish for Shaanxi residents. METHODS: The samples were determined by UPLC-MS/MS after purified by neutral alumina SPE cartridges and separated by waters-BEH C18 column (2.1 mm x 100 mm, 2.5 µm). The MOE method was used to assess the risk of intaking MG from freshwater fish for Shaanxi residents. RESULTS: The average detection rate of MG in freshwater fish in Shaanxi province was 7.32% and the highest residue level was 428 µg/kg. The detection rate was quite different in different fish species. The catfish devoted the highest detection rate which was 28.57%. In ten cities of Shaanxi, the highest detection rate was obtained from Yulin which was 33.33%. CONCLUSION: The health risk of intaking MG from freshwater fish is quite low for Shaanxi residents, however the contamination of illegal use of MG in freshwater fish was severe in Shaanxi Province. Supervision and inspection of MG should be strengthened in fish farming.

Photoreduction and origin of dissolved and particulate mercury in cloud water: Insights from stable mercury isotopes.

The photoreduction of mercury (Hg) in clouds is crucial for determining global Hg cycling. The recently-developed isotope approach provides new insight into the fate of atmospheric Hg, however, limited data have been reported on the dynamics of Hg isotopes in clouds. This study presented the isotopic compositions of dissolved mercury (DHg) and particulate mercury (PHg) in cloud water collected at Mt. Tai (1545 m a.s.l.) in eastern China during summer 2021. Both DHg and PHg exhibited positive mass-independent fractionation of odd isotopes (odd-MIF, denoted as Δ199Hg), with averaged Δ199Hg values of 0.83 ± 0.34‰ and 0.20 ± 0.11‰, respectively. This high odd-MIF likely resulted from aqueous photoreduction in clouds, with DHg being more susceptible to photolysis than PHg. Our findings indicated that the photoreduction was promoted by sunlight and influenced by the chemical compositions of cloud water that controlled the Hg(II) speciation. The isotope mixing model estimation revealed that particulate-bound Hg and reactive gaseous Hg constituted the principal sources of Hg in cloud water, accounting for 55% to 99% of the total, while gaseous element Hg also made a notable contribution. Additionally, cloud water samples with faster reduction rates of Hg(II) were located outside of the isotope mixing models, which indicated an enhanced photoreduction process in cloud water.

Changed mercury speciation in clouds driven by changing cloud water chemistry and impacts on photoreduction: Field evidence at Mt. Tai in eastern China.

Chemical speciation of mercury (Hg) in clouds largely determines the photochemistry of Hg in the atmosphere and consequently influences Hg deposition on the surface through precipitation. Cloud water chemistry has notably changed over the last decade in response to global changes, however, the effects on Hg speciation remain poorly understood. During summer 2021, we collected sixty cloud water samples at Mt. Tai in eastern China and compared the cloud chemistry and Hg speciation with our previous findings during summer 2015. The results showed that although there were no statistically significant differences in the concentrations of total Hg (THg), dissolved Hg (DHg), and particulate Hg (PHg), there was a distinct shift in DHg species from the predominated Hg-DOM (78.6% in 2015 campaign) to the more homogeneously distributed Hg(OH)2 (28.4% in 2021 campaign), HgBr2 (26.5%), Hg-DOM (17.3%) and HgBrOH (17.0%). Changes in cloud water chemistry, particularly the significant increase in pH values to 6.49 ± 0.27 and unexpectedly high levels of bromide ions (Br-, 0.19 ± 0.22 mg L-1), were found to drive the changing of Hg speciation by enhancing Hg(II) hydrolysis and binding by Br-. Elevated Br- originating primarily from the continent likely caused noticeable differences in the dominating DHg species between cloud water sourced from marine and continental regions. The changes in chemical speciation of DHg were estimated to result in a 2.6-fold decrease in Hg(II) photoreduction rate between 2015 and 2021 campaigns (0.178 ± 0.054 h-1 vs. 0.067 ± 0.027 h-1), implying a shortened lifetime of atmospheric Hg and increased ecological risks associated with Hg wet deposition.

Weighted gene co-expression network analysis and drug-gene interaction bioinformatics uncover key genes associated with various presentations of malaria infection in African children and major drug candidates.

Malaria is a fatal parasitic disease with unelucidated pathogenetic mechanism. Herein, we aimed to uncover genes associated with different clinical aspects of malaria based on the GSE1124 dataset that is publicly accessible by using WGCNA. We obtained 16 co-expression modules and their correlations with clinical features. Using the MCODE tool, we identified THEM4, STYX, VPS36, LCOR, KIAA1143, EEA1, RAPGEF6, LOC439994, ZBTB33, PTPN22, ESCO1, and KLF3 as hub genes positively associated with Plasmodium falciparum infection (ASPF). These hub genes were involved in the biological processes of endosomal transport, regulation of natural killer cell proliferation, and KEGG pathways of endocytosis and fatty acid elongation. For the purple module negatively correlated with ASPF, we identified 19 hub genes that were involved in the biological processes of positive regulation of cellular protein catabolic process and KEGG pathways of other glycan degradation. For the salmon module positively correlated with severe malaria anemia (SMA), we identified 17 hub genes that were among those driving the biological processes of positive regulation of erythrocyte differentiation. For the brown module positively correlated with cerebral malaria (CM), we identified eight hub genes and these genes participated in phagolysosome assembly and positive regulation of exosomal secretion, and animal mitophagy pathway. For the tan module negatively correlated with CM, we identified four hub genes that were involved in CD8-positive, alpha-beta T cell differentiation and notching signaling pathway. These findings may provide new insights into the pathogenesis of malaria and help define new diagnostic and therapeutic approaches for malaria patients.

CFCs measurements at high altitudes in northern China during 2017-2018: Concentrations and potential emission source regions.

Northern China was simulated as the main contributor to global chlorofluorocarbon (CFCs) that slowed down the recovery of stratospheric ozone layer in most recent studies. An atmospheric campaign was carried out from June 2017 to April 2018 to register the concentrations of typical chlorofluorocarbons (CFCs) (i.e., CFC-11, CFC-12, CFC-113, and CFC-114) at the top of Mount Tai, northern China. The mixing ratios of CFC-11 CFC-12, CFC-113, and CFC-114 were 257, 577, 80, and 18 pptv, respectively. These values are similar to the reported data 10 years ago at Mount Tai. CFC concentrations correlated well with those of benzene (an anthropogenic tracer) and were not affected by either humidity, temperature, or solar radiation. However, CFC concentrations were considerably influenced by regional transport: their backward trajectory and the PSCF (potential source contribution function) analysis suggested that higher concentrations (CFC-12, CFC-113 and CFC-114) were detected under the influence of air mass from the industrial regions in mid-eastern China and CFC-11 was through long-range transport from northwestern (i.e., from the higher atmosphere in western China) air masses. Overall, the findings of this study suggested that CFCs still have emissions in China, but no significant increase in recent years. Mid-eastern China might be responsible for the CFC emissions. The conclusions also highlight the need for the enforcement of effective control policies and the management of emissions, in order to avoid increasingly severe scenarios.

Glycyrrhetinic Acid and TAT Peptide Modified Dual-functional Liposomes for Treatment of Hepatocellular Cancer.

BACKGROUND: Surgery remains the front-line therapeutic strategy to treat early hepatocellular carcinoma (HCC). However, the 5-year recurrence rates of HCC patients are high. 10- Hydroxycamptothecin (10-HCPT) is a known anti-HCC agent but its poor solubility and bioavailability have limited its clinical use. OBJECTIVE: In this study, we developed a novel nanoliposome encapsulated 10-hydroxycamptothecin modified with glycyrrhetinic acid (GA) and TAT peptide (GA/TAT-HCPT-LP) for the treatment of HCC. Dual modified GA and TAT can enhance tumor targeting and tumor penetration. METHODS: The GA/TAT-HCPT-LP NPs were synthesized using the thin-film dispersion method. GA/TAT-HCPT-LP were characterized for particle size, zeta potential and morphology. Drug release from the GA/TAT-HCPT-LP liposomes was measured by dialysis. Cell-uptake was assessed by microscopy and flow cytometry. Cell proliferation, migration and apoptosis were measured to evaluate in vitro antitumor activity of GA/TAT-HCPT-LP via CCK-8 assays, Transwell assays, and flow cytometry, respectively. The in vivo distribution of GA/TAT-HCPT-LP was evaluated in HCC animal models. Tumor- bearing mouse models were used to assess the in vivo therapeutic efficacy of GA/TAT-HCPT-LP. RESULTS: The mean particle size and mean zeta potential of GA/TAT-HCPT-LP were 135.55 ± 2.76 nm and -4.57 ± 0.23 mV, respectively. Transmission electron micrographs (TEM) showed that the GA/TAT-HCPT-LP had a near spherical shape and a double-membrane structure. GA/TAT-HCPT-LP led to slow and continuous drug release, and could bind to HepG2 cells more readily than other groups. Compared to control groups, treatment with GA/TAT-HCPT-LP had a significantly large effect on inhibiting cell proliferation, tumor cell migration and cell apoptosis. In vivo assays showed that GA/TATHCPT- LP selectively accumulated in tumor tissue with obvious antitumor efficacy. CONCLUSION: In conclusion, the synthesized GA/TAT-HCPT-LP could effectively target tumor cells and enhance cell penetration, highlighting its potential for hepatocellular cancer therapy.

PM2.5-Bound Toxic Elements in an Urban City in East China: Concentrations, Sources, and Health Risks.

Concentrations of PM2.5-bound trace elements have increased in China, with increasing anthropogenic emissions. In this study, long-term measurements of PM2.5-bound trace elements were conducted from January 2014 to January 2015 in the urban city of Jinan, east China. A positive matrix factorization model (PMF) and health risk assessment were used to evaluate the sources and health risks of these elements, respectively. Compared with most Chinese megacities, there were higher levels of arsenic, manganese, lead, chromium, and zinc in this city. Coal combustion, the smelting industry, vehicle emission, and soil dust were identified as the primary sources of all the measured elements. Heating activities during the heating period led to a factor of 1.3⁻2.8 higher concentrations for PM2.5 and all measured elements than those during the non-heating period. Cumulative non-carcinogenic and carcinogenic risks of the toxic elements exceeded the safety levels by 8⁻15 and 10⁻18 times, respectively. Arsenic was the critical element having the greatest health risk. Coal combustion caused the highest risk among the four sources. This work provides scientific data for making targeted policies to control air pollutants and protect human health.

Rhodamine B in spices determined by a sensitive UPLC-MS/MS method.

Rhodamine B (RhB) is a banned food additive and has been classified as illegal colourant. Therefore, the risk of RhB contamination should be strictly monitored. In this study, a sensitive UPLC-MS/MS method was applied to monitor RhB in 292 various spices such as chilli, pepper and tomato products. The results showed 22.7% of chilli powder samples, 18.5% of pepper powder samples, 11.1% of chilli oil samples and 9.1% of pepper oil samples were contaminated with RhB. Chilli powder contained RhB up to 44,935 µg/kg with an average of 743 µg/kg, pepper powder up to 65.9 µg/kg with an average of 4.1 µg/kg, chilli oil up to 14.6 µg/kg with an average of 1.0 µg/kg and pepper oil up to 1.1 µg/kg with an average of 0.2 µg/kg, respectively. Considering the common consumption of chilli products and pepper products by so many consumers, RhB exposure is significant and should be decreased.

Polycyclic aromatic hydrocarbons (PAHs) associated with PM2.5 within boundary layer: Cloud/fog and regional transport.

A study of PM2.5-associated PAHs analysis at Mount Lushan (1165m) was conducted to investigate the distributions of PAHs in PM2.5 and influences of cloud/fog. The main purpose was to quantify the main emission sources of PAHs and estimate regional transport effects within the boundary layer. Mount Lushan is located between the boundary layer and troposphere, which is an ideal site for atmosphere transport investigation. The concentrations of PAHs in PM2.5 were analyzed with GC-MS. The results showed that the volume concentration was 6.98ng/m3 with a range from 1.47 to 25.17ng/m3 and PAHs mass were 160.24µg/g (from 63.86 to 427.97µg/g) during the sampling time at Mount Lushan. The dominant compounds are BbF, Pyr and BP. In terms of aromatic-ring PAHs distributions, 4-6-ring PAHs are predominant, indicating that the high-ring PAHs tend to contribute more than low-ring PAHs in particulates. Due to frequent cloud/fog days at Mount Lushan, PAHs concentrations in the PM2.5 were determined before and after cloud/fog weather. The results demonstrated that the cloud/fog and rain conditions cause lower PAHs levels. Regression analysis was used for studying the relationship of PAHs distributions with meteorological conditions like temperature, humidity and wind. The results showed that the temperature and wind speed were inversely related with PAHs concentration but humidity had no significant relationship. Furthermore, backward trajectories and PCA combined with DR (diagnostic ratio analysis) were employed to identify the influences of regional transport and main emission sources. The results revealed that PAHs in PM2.5 were mainly affected by regional transport with the main emissions by mobile vehicle and steel industry, which contributed about 56.0% to the total PAHs in the area of Mount Lushan. In addition, backward trajectories revealed that the dominant air masses were from the northwest accounting for about one third of total PAHs.

Characteristics and impacts of trace elements in atmospheric deposition at a high-elevation site, southern China.

To investigate the regional background trace element (TE) level in atmospheric deposition (dry and wet), TEs (Fe, Al, V, Cr, Mn, Ni, Cu, Zn, As, Se, Mo, Cd, Ba, and Pb) in 52 rainwater samples and 73 total suspended particles (TSP) samples collected in Mt. Lushan, Southern China, were analyzed using inductively coupled plasma-mass spectrometry (ICP-MS). The results showed that TEs in wet and dry deposition of the target area were significantly elevated compared within and outside China and the volume weight mean pH of rainwater was 4.43. The relative contributions of wet and dry depositions of TEs vary significantly among elements. The wet deposition fluxes of V, As, Cr, Se, Zn, and Cd exceeded considerably their dry deposition fluxes while dry deposition dominated the removal of pollution elements such as Mo, Cu, Ni, Mn, and Al. The summed dry deposition flux was four times higher than the summed wet deposition flux. Prediction results based on a simple accumulation model found that the content of seven toxic elements (Cr, Ni, Cu, Zn, As, Cd, and Pb) in soils could increase rapidly due to the impact of annual atmospheric deposition, and the increasing amounts of them reached 0.063, 0.012, 0.026, 0.459, 0.076, 0.004, and 0.145 mg kg-1, respectively. In addition, the annual increasing rates ranged from 0.05% (Cr and Ni) to 2.08% (Cd). It was also predicted that atmospheric deposition induced the accumulation of Cr and Cd in surface soils. Cd was the critical element with the greatest potential ecological risk among all the elements in atmospheric deposition.

Characteristics and potential sources of atmospheric particulate mercury in Jinan, China.

Measurements of atmospheric particulate mercury (PHg) were conducted at a suburban site in Jinan, China from June 2014 to December 2015. The average PHg concentration was 508.5±402.7pgm-3, and the average Hg content in PM2.5 (particles with a diameter of 2.5µm or less) was 6.60±5.82µgg-1. Both PHg and Hg content in PM2.5 aerosols were comparable to levels in some cities in China and were much higher than in cities in North America and Europe. Weak correlations were found between PHg and meteorological parameters. The correlations between PHg and other pollutants in ambient air, including SO2, CO and NOχ, together with their wind dependence were used for source analysis, which suggested coal-fired industries, cement plants and traffic emissions as potential local sources for the site. Cluster analysis of 36-h backward trajectories suggested that the regional transport from southwestern Shandong Province also contributed to PHg in Jinan.