Source-based health risk assessment of heavy metal contamination in soil: a case study from a polymetallic mining region in Southeastern Hubei, Central China.

To conduct a precise health risk assessment of heavy metals (HMs) in soil, it is imperative to ascertain the primary sources of potential health risks. In this study, we conducted comprehensive measurements of HMs, specifically focusing on the accumulation of Cu, Cd, Sb, Zn, and Pb in local soil, which may pose threats to environmental quality. To achieve our objective, we employed a method that combines positive matrix factorization with a health risk assessment model to quantify the health risks associated with specific sources. The results obtained from the geo-accumulation index indicate that the majority of HMs found in the local soil are influenced by anthropogenic activities. Among these sources, local industrial-related activities contributed the largest proportion of HMs to the soil at 34.7%, followed by natural sources at 28.7%, mining and metallurgy-related activities at 28.2%, and traffic-related activities at 8.40%. Although the non-carcinogenic and carcinogenic risks associated with individual HMs were found to be below safety thresholds, the cumulative health risks stemming from total HMs exceeded safety limits for children. Moreover, the unacceptable health risks for children originating from industrial-related activities, natural sources, and mining and metallurgy-related activities were primarily concentrated in proximity to mining sites and industrial areas within the local region. This investigation furnishes valuable insights that can aid governmental authorities in formulating precise control policies to mitigate health threats posed by soils in polymetallic mining areas.

The Predominant Sources of Heavy Metals in Different Types of Fugitive Dust Determined by Principal Component Analysis (PCA) and Positive Matrix Factorization (PMF) Modeling in Southeast Hubei: A Typical Mining and Metallurgy Area in Central China.

To develop accurate air pollution control policies, it is necessary to determine the sources of different types of fugitive dust in mining and metallurgy areas. A method integrating principal component analysis and a positive matrix factorization model was used to identify the potential sources of heavy metals (HMs) in five different types of fugitive dust. The results showed accumulation of Mn, Fe, and Cu can be caused by natural geological processes, which contributed 38.55% of HMs. The Ni and Co can be released from multiple transport pathways and accumulated through local deposition, which contributed 29.27%. Mining-related activities contributed 20.11% of the HMs and showed a relatively high accumulation of As, Sn, Zn, and Cr, while traffic-related emissions contributed the rest of the HMs and were responsible for the enrichment in Pb and Cd. The co-applied source-identification models improved the precision of the identification of sources, which revealed that the local geological background and mining-related activities were mainly responsible for the accumulation of HMs in the area. The findings can help the government develop targeted control strategies for HM dispersion efficiency.

Pollution Characteristics and Human Health Risk Assessment of Heavy Metals in Street Dust from a Typical Industrial Zone in Wuhan City, Central China.

This study aimed to assess the pollution levels, sources, and human health risks of heavy metals in street dust from a typical industrial district in Wuhan City, Central China. In total, 47 street dust samples were collected from the major traffic arteries and streets around Wuhan Iron and Steel (Group) Company (WISC) in Qingshan District, Wuhan. The concentrations of heavy metals (Cr, Mn, Ni, Zn, Fe, Cu, and Cd) in street dust were determined by atomic absorption spectroscopy. Results indicated that the mean concentrations of Zn (249.71 mg/kg), Cu (51.15 mg/kg), and Cd (0.86 mg/kg) in street dust were higher than their corresponding soil background values in Hubei Province. Heavy metal enrichment is closely related to urban transportation and industrial production. The pollution level of heavy metals in street dust was assessed using the geo-accumulation method (Igeo) and potential ecological risk assessment (PERI). Based on the Igeo value, Cr, Mn, Fe, and Ni showed no pollution, Zn and Cu showed light to moderate contamination, and Cd showed moderate contamination. The PERI values of heavy metals in street dust ranged between 76.70 and 7027.28, which represents a medium to high potential ecological risk. Principal component analysis showed that the sources of heavy metals in street dust were mainly influenced by anthropogenic activities. Among the studied metals, Cu, Cr, Zn, Fe, and Mn mainly come from industrial processes, while Ni and Cd come from traffic exhaust. The non-carcinogenic risk indexes of heavy metals for children and adults are ranked as Cr > Cu > Ni > Cd > Zn. The health risks to children through the different exposure pathways are higher than those for adults. Hand-to-mouth intake is the riskiest exposure pathway for non-carcinogenic risk. In addition, Cr, Ni, and Cd do not pose a carcinogenic risk for the residents.

Impact of short-term control measures on air quality: A case study during the 7th Military World Games in central China.

The 7th Military World Games held in Wuhan (WH) in Oct 2019 provided an opportunity to clarify the impact of short-term control measures on air quality. Fine particulate matters (PM2.5) were collected in WH, Huangshi (HS), and Huanggang (HG) during the control (Oct 13-28, 2019) and non-control periods (Oct 29- Nov 5, 2019). The results showed that air quality was good during the control period, with the concentrations of PM2.5 and gaseous pollutants being below the Grade Ⅱ of China Ambient Air Quality Standard. Concentrations of PM2.5 and its major chemical components in the control period were significantly lower than those in the non-control period, with reductions ranging from 17% (trace elements) to 46% (elemental carbon). However, higher contributions of secondary components such as SO42-, NO3-, NH4+ and secondary organic carbon (SOC) to PM2.5 were observed during the control period, suggesting the important role of secondary transformation. Potential source contribution function (PSCF) of PM2.5 showed that the main source regions were potentially located in surrounding cities Hubei Province, but regional transport can't be ignored. Six sources were identified by positive matrix factorization (PMF) for both control and non-control period. The contributions of combustion emissions and vehicle emissions were amplified in the control period, while the contribution of construction dust increased significantly when the control measures ended. Emission reductions contributed more to PM2.5 concentration decrease in WH (55%) than that in HS (51%) and HG (49%), which was consistent with the stricter control measures implemented in WH. These results indicated that short-term controls were effective at lowering PM2.5 concentration. However, the elevated contributions of secondary aerosols and the influence of regional transport on the study areas also need to be paid attention for air quality improvement in the future.

Pollution Characteristics and Associated Risk Assessment of Heavy Metals in Farmland Soils From a Typical County of Hubei Province, Central China.

Knowledge from the negative impacts of the counties' anthropogenic activities on soil pollution was of great significance in China, and valuable information was urgently needed for the control and remediation of soil pollution. The current pollution levels of heavy metals (Cu, Pb, Cd, Zn, Ni, and Cr) in farmland soils were investigated in Yangxin County, Hubei Province, central China. The comprehensive results of quantitative comparison and evaluation in this study showed that Cu (144.9 ± 298.6 mg kg-1), Cd (2.9 ± 1.6 mg kg-1), and Ni (137.0 ± 111.0 mg kg-1) posed higher pollution risks to public and ecosystem health, which were higher than the corresponding soil background values. The combined results of geostatistics, spatial and statistical analysis indicated that studied heavy metals were mainly attributed to agricultural, traffic and industrial induced pollution. Overall, urgent attention should be paid to the risk reduction and management of soil Cu, Cd, and Ni pollution in the study area.

Hazardous Heavy Metals Accumulation and Health Risk Assessment of Different Vegetable Species in Contaminated Soils from a Typical Mining City, Central China.

Heavy metal poisoning has caused serious and widespread human tragedies via the food chain. To alleviate heavy metal pollution, particular attention should be paid to low accumulating vegetables and crops. In this study, the concentrations of five hazardous heavy metals (HMs), including copper (Cu), chromium (Cr), lead (Pb), cadmium (Cd), and arsenic (As) were determined from soils, vegetables, and crops near four typical mining and smelting zones. Nemerow's synthetical pollution index (Pn), Potential ecological risk index (RI), and Geo-accumulation index (Igeo) were used to characterize the pollution degrees. The results showed that soils near mining and metal smelting zones were heavily polluted by Cu, Cd, As, and Pb. The total excessive rate followed a decreasing order of Cd (80.00%) > Cu (61.11%) > As (45.56%) > Pb (32.22%) > Cr (0.00%). Moreover, sources identification indicated that Cu, Pb, Cd, and As may originate from anthropogenic activities, while Cr may originate from parent materials. The exceeding rates of Cu, Cr, Pb, Cd, and As were 6.7%, 6.7%, 66.7%, 80.0%, and 26.7% among the vegetable and crop species, respectively. Particularly, vegetables like tomatoes, bell peppers, white radishes, and asparagus, revealed low accumulation characteristics. In addition, the hazard index (HI) for vegetables and crops of four zones was greater than 1, revealing a higher risk to the health of local children near the mine and smelter. However, the solanaceous fruit has a low-risk index (HI), indicating that it is a potentially safe vegetable type.

Assessment of Elemental Components in Atmospheric Particulate Matter from a Typical Mining City, Central China: Size Distribution, Source Characterization and Health Risk.

Atmospheric particulate matters in nine size fractions were sampled at Huangshi city, Hubei province. Elemental concentrations occurred unimodal size distribution for Zn, Pb and Ni, dimodal distribution for Ca, S, Fe and Ti, and trimodal distribution for Cl, K, Mn, Cu and Cr. Enrichment factor and principal component analysis identified the main sources from crustal material, biomass burning, waste incineration, vehicular and industrial emission. As for the non-carcinogenic health risk through inhalation, there were certain potential risks for Mn and Sb for children, and Pb for children and adults in PM2.5. It showed certain potential risks for Mn, Sb and Pb for children and adults in PM10. As for the carcinogenic health risk through inhalation, Cr in PM2.5 and Ni, Co and Cr in PM10 indicated unacceptable risk for children and adults. Meanwhile, Co and Ni in PM2.5 represented acceptable risk for children.

Polycyclic aromatic hydrocarbons in railway stations dust of the mega traffic hub city, central China: Human health risk and relationship with black carbon.

Twenty dust samples collected from Wuchang and Wuhan Railway Stations, the biggest transport stations in the mega traffic hub city in Central China, were analyzed for polycyclic aromatic hydrocarbons (PAHs) to investigate the concentration, sources apportionment, and relationship with black carbon (BC) and assess the health risk. The results suggested that the concentrations of PAHs, BC and TOC in Wuhan Railway Station (WHRS) (PAHs = 5940 ± 1920 ng g-1, BC = 53.2 ± 23.1 mg g-1 and TOC = 80.7 ± 44.4) were twice higher than those in Wuchang Railway Station (WCRS) (PAHs = 2580 ± 1630 ng g-1, BC = 20.4 ± 14.3 mg g-1 and TOC = 33.9 ± 20.1 mg g-1). Moreover, the 3 - and 4 - rings PAHs were major PAHs in railway station dust. The composition pattern of PAHs in these railway station dusts had a common characteristic with HMW-PAHs contribution. The results of source identification revealed that different local development features and energy consumption of trains would influence the sources of PAHs and BC. PAHs and BC were most likely related to industrial activities in WHRS. Coal and biomass combustion may influence the PAHs components and BC distribution in WCRS. Moreover, BC had played an important role in retaining PAHs in urban railway stations. Especially in WHRS, BC would more likely to absorb the high molecular weight PAHs, such as 4 -ring (p<0.05), 5 -ring (p<0.05) and 6 -ring (p<0.05) PAHs; while BC just played limited roles in the binding of volatile and semi-volatile organic pollutants, such as 2 -ring and 3 -ring PAHs. With the coexistence of BC and PAHs, passengers would face significant potential health risks by exposure to toxic dust in railway stations, especially for children. The cancer risk in WHRS was almost twice higher than that in WCRS, and it would tend to be stable by a semi-confined structure in the platform area.

Asian inland wildfires driven by glacial-interglacial climate change.

Wildfire can influence climate directly and indirectly, but little is known about the relationships between wildfire and climate during the Quaternary, especially how wildfire patterns varied over glacial-interglacial cycles. Here, we present a high-resolution soot record from the Chinese Loess Plateau; this is a record of large-scale, high-intensity fires over the past 2.6 My. We observed a unique and distinct glacial-interglacial cyclicity of soot over the entire Quaternary Period synchronous with marine δ18O and dust records, which suggests that ice-volume-modulated aridity controlled wildfire occurrences, soot production, and dust fluxes in central Asia. The high-intensity fires were also found to be anticorrelated with global atmospheric CO2 records over the past eight glacial-interglacial cycles, implying a possible connection between the fires, dust, and climate mediated through the iron cycle. The significance of this hypothetical connection remains to be determined, but the relationships revealed in this study hint at the potential importance of wildfire for the global climate system.

Atmospheric Concentrations and Air-Soil Exchange of Polycyclic Aromatic Hydrocarbons (PAHs) in Typical Urban-Rural Fringe of Wuhan-Ezhou Region, Central China.

During the summer of 2015, polycyclic aromatic hydrocarbons (PAHs) in the atmosphere were collected by passive air samplers in typical urban-rural fringe of Wuhan-Ezhou region, Central China. The results showed that 16 kinds of PAHs were ubiquitous with the concentrations of ∑16PAHs from 14.69 to 136.30 ng·m-3 and the mean concentration of 43.03 ng·m-3. Phenanthrene (Phe), fluoranthene (Fla) and pyrene (Pyr) were major components, which accounted for 81% of ∑16PAHs. PAHs atmospheric concentrations presented obvious spatial variation, being significantly related to geographical environment and influenced by anthropogenic activity. Air-soil exchange status of PAHs was discussed according to the fugacity fraction (ff). The results showed that HMW-PAHs behaved as net deposition, while LMW-PAHs were more likely to establish dynamic equilibrium between atmosphere and soil than MMW-PAHs and HMW-PAHs. For some PAHs, such as acenaphthylene (Acy) and anthracene (Ant), the soil acted as second sources of them.

A critical review on environmental implications, recycling strategies, and ecological remediation for mine tailings.

Mine tailings, generated from the extraction, processing, and utilization of mineral resources, have resulted in serious acid mine drainage (AMD) pollution. Recently, scholars are paying more attention to two alternative strategies for resource recovery and ecological reclamation of mine tailings that help to improve the current tailing management, and meanwhile reduce the negative environmental outcomes. This review suggests that the principles of geochemical evolution may provide new perspective for the future in-depth studies regarding the pollution control and risk management. Recent advances in three recycling approaches of tailing resources, termed metal recovery, agricultural fertilizer, and building materials, are further described. These recycling strategies are significantly conducive to decrease the mine tailing stocks for problematic disposal. In this regard, the future recycling approaches should be industrially applicable and technically feasible to achieve the sustainable mining operation. Finally, the current state of tailing phytoremediation technologies is also discussed, while identification and selection of the ideal plants, which is perceived to be the excellent candidates of tailing reclamation, should be the focus of future studies. Based on the findings and perspectives of this review, the present study can act as an important reference for the academic participants involved in this promising field.

Polycyclic aromatic compounds (PAHs, oxygenated PAHs, nitrated PAHs and azaarenes) in soils from China and their relationship with geographic location, land use and soil carbon fractions.

The assessment of risks arising from polycyclic aromatic compounds (PACs), particularly from the polar PACs [azaarenes (AZAs), oxygenated PAHs (OPAHs), nitrated PAHs (NPAHs)] requires us to understand the drivers of their spatial distribution. We determined the concentrations of 29 PAHs, 4 AZAs, 15 OPAHs and 11 NPAHs and their relationships with land use (urban vs. rural and forest vs. agriculture), climate (Qinghai-Tibetan plateau, temperate, sub tropical and tropical) and three C fractions (soil organic C, char, soot) in 36 mineral topsoils (0-5 cm) of China. The average concentrations±standard deviation of the Σ29PAHs, Σ16PAHs, Σ4AZAs, Σ15OPAHs and Σ11NPAHs were 352 ±â€¯283, 206 ±â€¯215, 5.7 ±â€¯3.7, 108 ±â€¯66.8 and 3.2 ±â€¯3.4 ng g-1, respectively. PAH, OPAH, NPAH and AZA concentrations were frequently not correlated within or across the regions reflecting different sources and turnover of PAHs and their derivatives. Temperate urban soils showed the highest and tropical rural soils the lowest concentrations of PACs. Forest soils had higher PACs concentrations than agricultural soils. Longitude correlated positively with the ∑29PAHs concentrations, because of increasing emissions of PAHs from East to West. The tropical and plateau regions with the lowest PAH concentrations, were dominated by low molecular weight PAHs (LMW-PAHs) with LMW/high molecular weight (HMW)-PAHs ratios >1, while the other two climatic regions with more industrial sites showed the opposite. Latitude correlated with NPAHs likely because of enhanced formation by photochemical reactions during transport in the atmosphere. The concentrations of the ∑29PAHs, ∑4AZAs, ∑15OPAHs, ∑11NPAHs and their individual components were only occasionally correlated with those of carbon fractions (soil organic C, soot and char) suggesting a small role of soil C pool properties in driving PACs concentrations. Our results demonstrate that the strongest drivers of PACs concentrations are land use and distance to PAC emission sources followed by climate and size and properties of the soil organic C pool.

Historical variation of black carbon and PAHs over the last ~200 years in central North China: Evidence from lake sediment records.

As the largest coal-producing province in China, the coal production of Shanxi Province accounts for one third of the country's total. Thus it is of great importance to study the pollution history of typical pollutants in Shanxi Province and their links with energy usage in North China. Sediment cores from two relatively remote lakes in central North China were retrieved to investigate historical evolutions of black carbon (BC) and polycyclic aromatic hydrocarbons (PAHs) in the last ~200 years. The two records show several-fold increases in both concentrations and depositional fluxes of BC, char, soot, and PAHs in recent five decades, which were associated with the influence of anthropogenic activities resulting from socio-economic development in Shanxi Province. However, after ~2000 their fluxes decreased sharply due to China's effort on environmental protection. These changes indicate that atmospheric BC and PAHs loads in the region were affected significantly by recent anthropogenic activities and environmental policies. Ratios of individual PAHs and char/soot indicate pyrogenic sources of these increased pollutants in recent decades, with coking industry and coal combustion as the two major sources. Significant positive correlations between BC and PAHs were observed in both cores of Lake Gonghai and Lake Mayinghai, indicating that they were likely co-transported by BC particles from similar sources. This study provides new and important understanding of the atmospheric pollution history of BC and PAHs in North China.

Characterization of carbonaceous fractions in PM2.5 and PM10 over a typical industrial city in central China.

Aerosol samples of PM2.5 and PM10 were collected every 6 days from March 2012 to February 2013 in Huangshi, a typical industrial city in central China, to investigate the characteristics, relationships, and sources of carbonaceous species. The PM2.5 and PM10 samples were analyzed for organic carbon (OC), elemental carbon (EC), char, and soot using the thermal/optical reflectance (TOR) method following the IMPROVE_A protocol. PM2.5 and PM10 concentrations ranged from 29.37 to 501.43 µg m-3 and from 50.42 to 330.07 µg m-3, with average levels of 104.90 and 151.23 µg m-3, respectively. The 24-h average level of PM2.5 was about three times the US EPA standard of 35 µg m-3, and significantly exceeds the Class II National Air Quality Standard of China of 75 µg m-3. The seasonal cycles of PM mass and OC concentrations were higher during winter than in summer. EC and char concentrations were generally highest during winter but lowest in spring, while higher soot concentrations occurred in summer. This seasonal variation could be attributed to different seasonal meteorological conditions and changes in source contributions. Strong correlations between OC and EC were found for both PM2.5 and PM10 in winter and fall, while char and soot showed a moderate correlation in summer and winter. The average OC/EC ratios were 5.11 and 4.46 for PM2.5 and PM10, respectively, with individual OC/EC ratios nearly always exceeding 2.0. Higher char/soot ratios during the four seasons indicated that coal combustion and biomass burning were the major sources for carbonaceous aerosol in Huangshi. Contrary to expectations, secondary organic carbon (SOC) which is estimated using the EC tracer method exhibited spring maximum and summer minimum, suggesting that photochemical activity is not a leading factor in the formation of secondary organic aerosols in the study area. The contribution of SOC to OC concentration for PM2.5 and PM10 were 47.33 and 45.38%, respectively, implying that SOC was an important component of OC mass. The serious air pollution in haze-fog episode was strongly correlated with the emissions of pollutants from biomass burning and the meteorological conditions.

Dicarboxylic acids and related compounds in fine particulate matter aerosols in Huangshi, central China.

PM2.5 (particulate matter with an aerodynamic diameter <2.5 µm) samples were collected in Huangshi, central China, from March 2012 to February 2013 and were analyzed for dicarboxylic acids (diacids) and related compounds (DARCs). Oxalic acid (C2; 416 ng m-3) was the most abundant species, followed by phthalic (Ph; 122 ng m-3), terephthalic (tPh; 116 ng m-3), succinic (C4; 70.4 ng m-3), azelaic (C9; 67.9 ng m-3), and adipic (C6; 57.8 ng m-3) acids. Relatively high abundances of Ph and tPh differed from the distribution in urban and marine aerosols, indicating contributions from nearby anthropogenic sources. Glyoxylic acid (ωC2; 41.4 ng m-3) was the dominant oxoacid, followed by 9-oxononanoic (ωC9; 40.8 ng m-3) and pyruvic (Pyr; 24.1 ng m-3) acids. Glyoxal (Gly; 35.5 ng m-3) was the dominant α-dicarbonyl. Highest average concentrations were found for C2, ωC2, and C9 in autumn, for C4, for Pyr and C6 in spring, for Ph, ωC9, and Gly in summer, whereas the lowest values were observed in winter. Seasonal variations and correlation coefficients of DARCs demonstrate that both primary emissions and secondary production are important sources. Principal component analysis of selected DARCs species suggests that a mixing of air masses from anthropogenic and biogenic sources contribute to the Huangshi aerosols. Implications: Both primary emissions and secondary production are important sources of diacids and related compounds in PM2.5 from Huangshi, central China. Principal component analysis of selected diacids in Huangshi aerosols suggests that mixing of air masses from anthropogenic and biogenic sources contribute to ambient aerosols in central China.

Contamination characteristics and potential environmental implications of heavy metals in road dusts in typical industrial and agricultural cities, southeastern Hubei Province, Central China.

In November 2013, the total concentration of selected heavy metals in 43 urban dust samples, collected from two small-sized cities of industrial E'zhou and agricultural Huanggang, located in the southeastern Hubei province, central China, was detected quantitatively by flame atomic absorption spectrometric (FAAS) for ultimate purpose of pollution monitoring and risk evaluation. Results indicated that the mean concentrations exceeding their respective background values were observed for all the investigated metals, with the exception of Co (13.08mg kg-1) and Fe (38635.02mg kg-1) in Huanggang road dusts, whose average concentrations were close to the background levels. In comparison with the reference data reported from the selected cities worldwide, the urban road dusts were seriously polluted by heavy metals to diverse degrees. The contour distribution maps implied that obviously higher values zones were found between two different types of urban areas, located to both sides of the coastline of Yangtze River. Multivariate statistical analysis revealed that the enriched heavy metals had emanated from the combined effects of both natural sources and anthropogenic sources. Three pollution indices indicated that the riskiest element mainly comprising Cr, Ni, Cu, and Pb appeared to be the major contributors to the urban environmental pollution. Avoiding continuous damage requires, the riskiest metallic contaminants should be paid preferential attention to.

[Distribution, Sources and Risk Assessment of the PAHs in the Surface Sediments and Water from the Daye Lake].

8 surface sediments and 8 water samples were collected from the Daye Lake in August 2015.The 16 kinds of EPA control polycyclic aromatic hydrocarbons (PAHs) were analyzed by GC-MS.The results showed that the PAHs concentrations of surface sediments and water ranged from 35.94 ng·g-1 to 2032.73 ng·g-1 and from 27.94 ng·L-1 to 242.95 ng·L-1,with average contents of 940.61 ng·g-1 and 107.77ng·L-1,respectively.The distribution of PAHs in surface sediments indicated that the contents in the center samples were higher than those in the bank samples,but the water showed nearly the opposite tendency.The 4-5 rings high molecular weight PAHs were the main components in the surface sediments,and the 2,4 and 5 rings PAHs were given priority in water.Compared with the other domestic and oversea lakes,the PAHs pollution of the Daye Lake was at a moderate level.Source apportionment showed that the PAHs in surface sediments and water from the Daye Lake came from the combustion source,HWM-PAHs were the dominant part of the PAHs in the sediment,reflecting the sediment PAHs pollution under the effects of mining and smelting over a long period;All monomer PAHs and total PAHs content in sediment did not exceed the ERM and FEL limiting values,showing that there was no particularly serious ecological risk caused by PAHs in the surface sediments from the Daye Lake;the incremental lifetime cancer risks assessment showed that the uptake risk of PAHs in Daye Lake water through the ingestion and dermal absorption were both in the acceptable range recommended by the USEPA,but all sites had higher risk than the acceptable risk level recommended by the Sweden environmental protection agency and Royal society.The pollution of seven carcinogenic PAHs needs prevention and control.

[Pollution Characteristics and Risk Assessment of Heavy Metals in Water and Sediment from Daye Lake].

The surface water and surface sediments were collected from Daye Lake in April 2014. The concentrations of heavy metals were determined by atomic absorption spectroscopy. The pollution potential health risk and ecological risk of heavy metals in water and sediment were assessed by the health risk assessment model and the potential ecological risk index method. The results showed that the concentrations of the heavy metals (Ni, Cd, Cu and Pb) was 49.27 µg·L-1, 2.19 µg·L-1, 12.18 µg·L-1, 12.13 µg·L-1(water) and 78.46 mg·kg-1, 77.13 mg·kg-1, 650.13 mg·kg-1 and 134.22 mg·kg-1 (sediment). Enrichment coefficient indicated that the enrichment of Cd, Cu and Pb was more serious, especially the accumulation of Cd was the most obvious. Compared to typical lakes in China, the contents of heavy metals in water and sediment were relatively high. The spatial pollutant distribution of the heavy metals in water and sediment all presented that the concentrations of the heavy metals were relatively higher in east and west of Daye Lake, relatively more uniform in the middle, and their origins were mainly from human activities. The results of environmental risk indicated that the carcinogens and chemical non-carcinogens health risk values of heavy metals by drinking water pathway were 9.77E-08~1.63E-05a-1. Therefore, the pollution of Ni and Cd should be the primary control target for environmental health risk management. The descending order of pollution degree of four metals in sediment was Cd> Cu> Pb> Ni, and Cd was the main contributor of the potential ecological risk elements.

[Characteristics and Sources of Elements of a PM10 Measurements from a Typical Industrial City in Eastern Hubei Province].

In order to investigate the characteristics and sources of elements in atmospheric aerosols (PM10) measurements, samples were collected between April 2012 and February 2013 in Huangshi, a typical industrial city in the east of Hubei province, China. These samples were analyzed for seventeen elements using wavelength dispersive X-ray fluorescence spectrometry. In addition, the pollution characteristics of fourteen elements were analyzed by an enrichment factor (EF) method, and the sources of these elements were studied by a principal component analysis (PCA) and positive matrix factorization (PMF) method. The result from the EF indicated that the concentration of the seventeen elements in the PM10 measurements varied from 0.01-9.83 µg·m-3. The elemental concentration of S was the highest and Ni and V was the lowest during the monitoring period in Huangshi. Daily levels of Pb and Cd exceeded the annual reference values set by the National Ambient Air Quality Standard (GB3095-2012) by 36.4% and 89.1%, respectively. An analysis of EF showed that Ti, V, Mn, and Ni elements were mildly enriched, indicating they were affected by both natural and anthropogenic sources. Ca, Cr, and Ba elements were moderately enriched and Cu, Zn, Pb, Sn, Sb, and Fe were highly enriched or hyper accumulated, suggesting they are mainly sourced from human activities. There were four sources significantly contributing to the elements in the PM10measurement, which were determined using PCA and PMF analysis. These were soil and fugitive dust, coal combustion, industry exhausts, and motor vehicle emissions. The results of the two models supported each other and had good consistency.

[Concentration and Size Distribution of Bioaerosols in Indoor Environment of University Dormitory During the Plum Rain Period].

Bioaerosols of university dormitory can spread through air and cause a potential health risk for student staying in indoor environment. To quantify the characteristics of bioaerosols in indoor environment of university dormitory, concentration and size distribution of culturable bioaerosols were detected during the plum rain period, the correlations of culturable bioaerosol with concentration of particulate matter, the ambient temperature and relative humidity were analyzed using Spearman's correlation coefficient and finally the changes of size distribution of culturable bioaerosol caused by activities of students were detected. The results showed that the mean concentrations of culturable airborne bacteria and fungi were (2133 +/- 1617) CFUm' and (3111 +/- 2202) CFU x m(-3). The concentrations of culturable airborne bacteria and fungi exhibited negative correlation with PM1, PM2.5, and PM10, respectively. The respirable fractions of bacteria exhibited positive correlation with PM2.5, and the respirable fractions of fungi exhibited significant positive correlation with PM10. Ambient temperature had positive correlation with culturable airborne bacteria and fungi, and relative humidity had negative correlation with culturable airborne bacteria and fungi. In the afternoon, concentrations of culturable airborne fungi in indoor environment of university dormitory significantly increased, and the size distribution of culturable hioaerosols was different in the morning and afternoon.