Metals In PM2 Research Articles

Association between personal exposure to metals in fine particulate matter and urinary metals: baseline results from a panel study

To investigate the associations between 21 metals in fine particulate matter (PM2.5) and their corresponding concentrations in urine in the general population. Between April and May 2011, this panel study enrolled 120 residents using random sampling approach in Wuhan communities which contained 3 035 subjects. Participants were aged 18 to 80 years and had lived in the sampling buildings for at least 5 years. Data from basic questionnaires, physical examinations, and morning blood and urine samples under fasting conditions were collected. Participants with missing data were excluded. Finally, 83 particpants included. Participants were instructed to use personal air samplers to continuously monitor PM2.5 for 24 h. The following 21 metals were measured in PM2.5 and urine by inductively coupled plasma mass spectrometry: aluminum, titanium, vanadium, chromium, manganese, cobalt, nickel, copper, zinc, arsenic, selenium, rubidium, strontium, molybdenum, cadmium, tin, antimony, barium, tungsten, thallium and lead. The associations between PM2.5 metals and urinary metals were investigated using generalized linear regression models. The age of the study population was (51.5±6.3)years. After adjusting for age, sex, smoking status, BMI, education and income, elevated urinary chromium was significantly associated with increased chromium concentrations in personal PM2.5. The least square means (standard deviation) of urinary chromium in participants classified as having low exposure (<12.491 ng/m(3)), intermediate exposure (12.491-32.388 ng/m(3)) and high exposure (>32.388 ng/m(3)) were (-1.334±0.756), (-1.114±0.813) and (-0.718±0.645) μg/mmol creatinine, respectively (P=0.009). However, the association between urinary and personal PM chromium was not observed after additionally adjusting for false discovery rate (P>0.05). Furthermore, the results demonstrated that other metals in PM2.5 were not related to their corresponding concentrations in urine of subjects. Urinary concentrations of metals did not reflect human exposure to metals in air, and may not be appropriate as an index to assess personal exposure to metals in particulate matter.

Atmospheric pollution from point and diffuse sources in a National Interest Priority Site located in Italy

The purpose of this paper is the assessment of the environmental air pollution in a very densely inhabited area in the southern Italy, which is characterised by serious general contamination. Because the air pollution may have an impact on human health, this area was identified in 1998 as a National Interest Priority Site and comprises a large part of agricultural lands belonging to over 60 municipalities between Naples and Caserta provinces. This study characterises the air pollution affecting this area by estimating the total annual emissions of the major pollutants (CO, NOX, VOC, PM and heavy metals) and showing their municipal spatial disaggregation. In this study a bottom-up methodology was employed, then focusing at regional level instead of national and comprising local and specific parameters. The pollutants emitted from several sources in the area under investigation were obtained by direct measurements of the principal industrial point sources, whereas the emissions from diffuse sources were calculated on the basis of local activity indicators and specific emission factors concerning the relevant activities in this area. The results obtained in this research have identified local critical factors.

Chemical composition and source apportionment of PM2.5 during Chinese Spring Festival at Xinxiang, a heavily polluted city in North China: Fireworks and health risks

Twenty-four PM2.5 samples were collected at a suburban site of Xinxiang during Chinese Spring Festival (SF) in 2015. 10 water-soluble ions, 19 trace elements and 8 fractions of carbonaceous species in PM2.5 were analyzed. Potential sources of PM2.5 were quantitatively apportioned using principal component analysis (PCA)-multivariate linear regressions (MLR). The threat of heavy metals in PM2.5 was assessed using incremental lifetime cancer risk (ILCR). During the whole period, serious regional haze pollution persisted, the average concentration of PM2.5 was 111±54μgm−3, with 95.8% and 79.2% of the daily samples exhibiting higher PM2.5 concentrations than the national air quality standard I and II. Chemical species declined due to holiday effect with the exception of K, Fe, Mg, Al and K+, Cl−, which increased on Chinese New Year (CNY)'s Eve and Lantern Festival in 2015, indicating the injection of firework burning particles in certain short period. PM2.5 mass closure showed that secondary inorganic species were the dominant fractions of PM2.5 over the entire sampling (37.3%). 72-hour backward trajectory clusters indicated that most serious air pollution occurred when air masses transported from the Inner Mongolia, Shanxi and Zhengzhou. Health risk assessment revealed that noncancerous effects of heavy metals in PM2.5 of Xinxiang were unlikely happened, while lifetime cancer risks of heavy metals obviously exceeded the threshold, which might have a cancer risk for residents in Xinxiang. This study provided detailed composition data and first comprehensive analysis of PM2.5 during the Spring Festival period in Xinxiang.

Particles in different indoor microenvironments-its implications on occupants

Changes over recent decades in outdoor concentrations of air pollutants are well documented. However, the impacts of air pollution on an individual’s health actually relate not to these outdoor concentrations, but to their personal environment in indoors where they spend most of their time. For this a campainage study was conducted in three different microenvironments, i.e., offices, shops and commercial centers; for each site, we choose two different locations to examine the coarse particles (PM10 & PM5.0) and fine particles (PM2.5, PM1.0, PM0.5 & PM0.25) concentrations which varied from 288 to 327 μg m-3 for PM10, 201.58–272.98 for PM5.0, 185.68–227.44 for PM2.5, 105.85–139.17 for PM1.0, 52.78–101.33 for PM0.5 and 36.48–56.13 for PM0.25. Metal concentration of Zn, Pb, Ni, Fe, Cr, Cd, Mg and Cu in PM2.5 and for their related health effects have also been analysed. The concentration values of heavy metals in PM2.5 were measured using Atomic Absorption spectrophotometry. The exposure factor and health risk assessment for carcinogenic effects due to heavy metal contaminants like (Cr, Cd, Ni and Pb) have been calculated for adults working in different indoor environment by following the methodology prescribed by US EPA. Ni had the highest Excess Cancer Risks followed by Cd and Cr in the different indoor environment. Three factors each in different indoor environment have been identified using Positive Matrix Factorization. The campainage study was carried from September 2011 to December 2011.

Sources of trace metals in PM10 from a petrochemical industrial complex in Northern Mexico

Concentrations, sources, and relative contributions of Cd, Cr, Cu, Fe, Mn, Pb, Ni, Ti, V, and Zn observed in PM10 in the petrochemical industrial zone of Altamira in Northern Mexico are reported for the first time. Results show that oil refining, alloys, fertilizer, mining, metallurgical processes, and steel production industries are important contributions to PM10 and metal concentrations. PM10 concentrations ranged from 21 to 92 μg m−3 and exceeded the revised 24-h average Mexican standard NOM-025-SSA1-2014 of 75 μg m−3 12 % of the study period. The highest metal concentrations were Fe (1.64 μg m−3), Mn (0.57 μg m−3), and Ti (0.29 μg m−3) and were associated with two dominant wind directions. Ti and Fe were associated with NNW winds (natural sources), and Mn and Fe were associated with SSW winds (ferromanganese industry). An average V/Ni ratio of 8.5 was found in this study with highest ratios associated to two dominant wind directions, NNW-NW and SE-SSE, suggesting origins from a fuel oil thermoelectric power plant and a refinery fuel oil, respectively. Pb was associated with industrial activity and never exceeded the Mexican standard of 1.5 μg m−3 in 24 h. Zn and Cd were correlated with a dominant easterly wind, suggesting the presence of vehicle exhaust pollutants. The study of the size and shape of PM10 particles by scanning electronic microscopy and energy-dispersive spectroscopy (SEM-EDS) allowed us to confirm the presence of trace metals associated to natural soils and clays, combustion, and industrial processes. The results presented here constitute the first efforts to evaluate toxic metals in a heavily industrialized area in Mexico and can be used to develop air quality management programs.

몽골 울란바토르 시 전통 주거공간의 실내공기 오염 기초조사

Objectives: The traditional type of residence in used in Mongolia, called a ger, is an important residential form and applies coal combustion for cooking and heating. The combustion of coal in ger is the major source of indoor air pollution. The purposes of this study were to measure indoor air pollution in ger and determine the effect of cooking and heating activities. Methods: Indoor temperature, relative humidity, particulate matter less than 2.5 μm (PM2.5) and black carbon (BC) were continuously measured for 24 hours in eight ger. The measurements were conducted in January or February 2015. Heavy metals in PM2.5 filter samples were analyzed by ICP-MS. Results: Average indoor temperature and relative humidity were 19.6 ±4.6°C and 21.4±5.2%, respectively. The average indoor PM2.5 concentration in the eight ger was 119.8 μg/m 3 and ranged from 69.4 to 202.7 μg/m. The peak concentrations of PM2.5 and BC during cooking and heating periods were several times higher than the 24hour average concentration. Conclusion: The major contributor to indoor PM2.5 and BC concentrations in the ger was coal combustion for cooking and heating.

Heavy metals in PM2.5 and in blood, and children's respiratory symptoms and asthma from an e-waste recycling area

This study was to investigate the levels of heavy metals in PM2.5 and in blood, the prevalence of respiratory symptoms and asthma, and the related factors to them. Lead and cadmium in both PM2.5 and blood were significant higher in Guiyu (exposed area) than Haojiang (reference area) (p < 0.05), however, no significant difference was found for chromium and manganese in PM2.5 and in blood. The prevalence of cough, phlegm, dyspnea, and wheeze of children was higher in Guiyu compared to Haojiang (p < 0.05). No significant difference was found for the prevalence of asthma in children between Guiyu and Haojiang. Living in Guiyu was positively associated with blood lead (B = 0.196, p < 0.001), blood cadmium (B = 0.148, p < 0.05) and cough (OR, 2.37; 95% CI, 1.30–4.32; p < 0.01). Blood lead>5 μg/dL was significantly associated with asthma (OR, 9.50; 95% CI, 1.16–77.49). Higher blood chromium and blood manganese were associated with more cough and wheeze, respectively. Our data suggest that living in e-waste exposed area may lead to increased levels of heavy metals, and accelerated prevalence of respiratory symptoms and asthma.

Size resolved metal distribution in the PM matter of the city of Turin (Italy)

A work on the characterization of the air quality in the city of Turin was carried out in different sampling periods, reflecting early autumn and winter conditions, including a snow episode during the early 2012 European cold wave.The concentrations of 13 elements in eight size fractions of the aerosol were determined using inductively coupled plasma-mass spectrometry. The collection was carried out with a Andersen MkII cascade impactor.The size distribution of elements allowed the identification of three main behavioural types: (a) elements associated with coarse particles (Cd, Cr, Cu, Fe, Mn, Mo and Sn); (b) elements found within fine particles (As, Co, Pb and V) and (c) elements spread throughout the entire size range (Ni and Zn).Principal Component Analysis allowed to examine the relationships between the inorganic elements and to infer about their origin. Chemometric investigation and assessment of similarity in the distribution led to similar conclusions on the sources.The concentration of gaseous trace pollutants (O3, NOx and VOCs) was determined. The concentrations of these pollutants are scarcely correlated with the metal contents of all the size classes of the PM. The differences found in the O3, NO2 and VOCs levels of the two winter campaigns due to the high photochemical reactivity in the period after the snow episode, do not reflect in differences in the metals distribution in the PM. Since PM metals, NOx and VOC have common sources, this behaviour is due to relevant differences in the transformation and deposition processes.

Fine particulate matter in the tropical environment: monsoonal effects, source apportionment, and health risk assessment

Abstract. The health implications of PM2.5 in the tropical region of Southeast Asia (SEA) are significant as PM2.5 can pose serious health concerns. PM2.5 concentration and sources here are strongly influenced by changes in the monsoon regime from the south-west quadrant to the north-east quadrant in the region. In this work, PM2.5 samples were collected at a semi-urban area using a high-volume air sampler at different seasons on 24 h basis. Analysis of trace elements and water-soluble ions was performed using inductively coupled plasma mass spectroscopy (ICP-MS) and ion chromatography (IC), respectively. Apportionment analysis of PM2.5 was carried out using the United States Environmental Protection Agency (US EPA) positive matrix factorization (PMF) 5.0 and a mass closure model. We quantitatively characterized the health risks posed to human populations through the inhalation of selected heavy metals in PM2.5. 48 % of the samples collected exceeded the World Health Organization (WHO) 24 h PM2.5 guideline but only 19 % of the samples exceeded 24 h US EPA National Ambient Air Quality Standard (NAAQS). The PM2.5 concentration was slightly higher during the north-east monsoon compared to south-west monsoon. The main trace metals identified were As, Pb, Cd, Ni, Mn, V, and Cr while the main ions were SO42−, NO3−, NH4+, and Na. The mass closure model identified four major sources of PM2.5 that account for 55 % of total mass balance. The four sources are mineral matter (MIN) (35 %), secondary inorganic aerosol (SIA) (11 %), sea salt (SS) (7 %), and trace elements (TE) (2 %). PMF 5.0 elucidated five potential sources: motor vehicle emissions coupled with biomass burning (31 %) were the most dominant, followed by marine/sulfate aerosol (20 %), coal burning (19 %), nitrate aerosol (17 %), and mineral/road dust (13 %). The hazard quotient (HQ) for four selected metals (Pb, As, Cd, and Ni) in PM2.5 mass was highest in PM2.5 mass from the coal burning source and least in PM2.5 mass originating from the mineral/road dust source. The main carcinogenic heavy metal of concern to health at the current location was As; the other heavy metals (Ni, Pb, and Cd) did not pose a significant cancer risk in PM2.5 mass concentration. Overall, the associated lifetime cancer risk posed by the exposure of hazardous metals in PM2.5 is 3–4 per 1 000 000 people at this location.

Ambient Air Heavy Metals in PM2.5 and Potential Human Health Risk Assessment in an Informal Electronic-Waste Recycling Site of China

ABSTRACTIn this study, we characterized the concentration of heavy metals in PM2.5 in the community with e-waste dismantling, Guiyu, China and assessed potential public health risk associated with heavy metal composition of PM2.5 for local residents. Daily samples of PM2.5 were collected with Harvard Impactors on the roof of 3-story buildings from March 2012–April 2013 in Guiyu (n = 133) and seasonal samples were collected in a reference site, Haojiang (n = 33). The concentrations of PM2.5 mass and heavy metals were analyzed gravimetrically and by graphite furnace atomic absorption spectrometry, respectively. The geometric mean concentrations of PM2.5, Pb and Cd in Guiyu were higher than in the reference area (PM2.5: 49.9 µg m–3 vs. 37.6 , p 0.05; Mn: 17 ng m–3 vs. 16 ng m–3, p > 0.05). The metal concentrations in PM2.5 from Guiyu were also higher when compared to other Asian cities. We observed higher heavy metal concentrations during winter and spring than summer and fall. Human health risk assessment showed that the total potential cancer risk for both adults and children are higher than the safe acceptable range recommended by the US EPA. Furthermore, the carcinogenic and non-carcinogenic elements in PM2.5 pose higher public health risk to children than adults. The results indicate that air pollution emitted from informal e-waste recycling activities might be affecting the health of local residents, especially children.

A Case Study of PM2.5 Characterization in Bangi, Selangor, Malaysia during the Southwest Monsoon Season

A case study was carried out to characterize the ambient PM_(2.5) based on ground-based sampling in Bangi, Selangor, Malaysia in September, 2013 during the southwest monsoon season. We determined the total mass concentration, organic carbon, elemental carbon (EC), and metals in PM_(2.5) samples. The mean PM_(2.5) mass concentration was 44.5 μg m^(-3), showing that it exceeded the national air quality standard of 35 μg m^(-3) for 24-hour PM_(2.5) by the U.S. Environmental Protection Agency. Relatively high OC and EC concentrations of this study compared to those of other Southeast Asian countries were observed, which indicate that significant sources of OC and EC exist. The results of char-EC/soot-EC ratios strongly suggest that biomass burning is the main contributor to ambient EC concentrations compared to coal combustion and motor vehicle emissions. From calculations using the mass closure model, organic matter was the most abundant component in PM_(2.5) mass at 22.4 ± 6.65 μg m^(-3), followed by nss-sulfate at 4.84 ± 2.49 μg m^(-3), and EC at 4.11 ± 0.916 μg m^(-3). This result indicates that targeting the sources of carbonaceous PM_(2.5) is a crucial step to improve the air quality in this study field.

Freight Transport Pollution Propagation at Urban Areas Based on Szczecin Example

Transport is one of the main sectors of the economy, which has a significant impact on the economic development of the country. The increase in the development of transport and transport infrastructure itself definitely develops the economic potential of the country, strengthens its economic, social cohesion and economic competitiveness. Depending on the type of emitted substances, transport pollution is of local or global nature. Considering the emission of pollutants in urban agglomeration, emitted toxic compounds mainly impact the local pollution of the environment. The primary toxic pollutants emitted into the environment from combustion of fuels include mainly: carbon monoxide CO, aliphatic and aromatic hydrocarbons (including benzo(a)pyrene), sulphur dioxide SO2, nitric oxide NOx and particulate matter PM (soot, tar) and heavy metals. The paper is focused on model of urban freight transport influences on city environment. The road, as a line source of pollution, is included in the model with a set of emitters and concerns finite straight line with a constant source of emissions per unit length and a constant effective source height. In order to perform modelling it is necessary to divide vehicles into categories, which forms the basis for determining the characteristics of the emission. The model will cover simulation of the distribution of pollutants for vehicle traffic stream in a communication network of the city. In the first case, study will be conducted for the straight sections of road, and then combined into a junction, which will allow for identification of the impact of traffic on air quality in different parts of the urban area. The example area of analysis includes chosen streets in Szczecin city centre. The basis of the analysis are the data collected during the survey and using traffic detectors.

Impact of maritime traffic on polycyclic aromatic hydrocarbons, metals and particulate matter in Venice air.

Harbours are important hubs for economic growth in both tourism and commercial activities. They are also an environmental burden being a source of atmospheric pollution often localized near cities and industrial complexes. The aim of this study is to quantify the relative contribution of maritime traffic and harbour activities to atmospheric pollutant concentration in the Venice lagoon. The impact of ship traffic was quantified on various pollutants that are not directly included in the current European legislation for shipping emission reduction: (i) gaseous and particulate PAHs; (ii) metals in PM10; and (iii) PM10 and PM2.5. All contributions were correlated with the tonnage of ships during the sampling periods and results were used to evaluate the impact of the European Directive 2005/33/EC on air quality in Venice comparing measurements taken before and after the application of the Directive (year 2010). The outcomes suggest that legislation on ship traffic, which focused on the issue of the emissions of sulphur oxides, could be an efficient method also to reduce the impact of shipping on primary particulate matter concentration; on the other hand, we did not observe a significant reduction in the contribution of ship traffic and harbour activities to particulate PAHs and metals. Graphical abstract Impact of maritime traffic on polycyclic aromatic hydrocarbons, metals and particulate matter and evaluation of the effect of an European Directive on air quality in Venice.

The Current Status of Traffic Nitrogen Oxides Pollution in Cluj – Napoca

Assessing air quality in high urbanized areas and finding solution for most important pollutants (NOx, CO, SO 2 , VOC, PM, O 3 , and heavy metals emissions) remains a challenge for authorities and public in aimed areas. The harmful effects upon humans and environmental health is the reason of all concerns. Lots of studies have been developed, in this area, worldwide. Majority of these state that traffic is the most important source of air pollution in crowded cities. The aim of this study consists in establishing the status quo of NOx pollution status in Cluj - Napoca. NOx air pollution was quantified during a year period (2013), in two locations correspondent to high traffic and position of automatic air quality monitoring stations placed by The Agency of Environmental Protection Cluj. Parameters were monitored using a mobile equipment. The average values of the analyzed parameters are different function of monitoring point. We noticed statistically significant differences between monitoring points, but in all cases the average concentrations are over the maximum admitted annual limit, 30 ppb, respectively. Further research and more intense concerns are needed from both public and authorities, in order to diminish the nitrogen oxides quantity in environmental air.

Contribution of heavy metals to toxicity of coal combustion related fine particulate matter (PM2.5) in Caenorhabditis elegans with wild-type or susceptible genetic background.

Contribution of chemical components in coal combustion related fine particulate matter (PM2.5) to its toxicity is largely unclear. We focused on heavy metals in PM2.5 to investigate their contribution to toxicity formation in Caenorhabditis elegans. Among 8 heavy metals examined (Fe, Zn, Pb, As, Cd, Cr, Cu, and Ni), Pb, Cr, and Cu potentially contributed to PM2.5 toxicity in wild-type nematodes. Combinational exposure to any two of these three heavy metals caused higher toxicity than exposure to Pb, Cr, or Cu alone. Toxicity from the combinational exposure to Pb, Cr, and Cu at the examined concentrations was higher than exposure to PM2.5 (100 mg/L). Moreover, mutation of sod-2 or sod-3 gene encoding Mn-SOD increased susceptibility in nematodes exposed to Fe, Zn, or Ni, although Fe, Zn, or Ni at the examined concentration did not lead to toxicity in wild-type nematodes. Our results highlight the potential contribution of heavy metals to PM2.5 toxicity in environmental organisms.

Source apportionment and health risk assessment of PM10 in a naturally ventilated school in a tropical environment

This study aimed to investigate the chemical composition and potential sources of PM10 as well as assess the potential health hazards it posed to school children. PM10 samples were taken from classrooms at a school in Kuala Lumpur's city centre (S1) and one in the suburban city of Putrajaya (S2) over a period of eight hours using a low volume sampler (LVS). The composition of the major ions and trace metals in PM10 were then analysed using ion chromatography (IC) and inductively coupled plasma-mass spectrometry (ICP-MS), respectively. The results showed that the average PM10 concentration inside the classroom at the city centre school (82µg/m3) was higher than that from the suburban school (77µg/m3). Principal component analysis-absolute principal component scores (PCA-APCS) revealed that road dust was the major source of indoor PM10 at both school in the city centre (36%) and the suburban location (55%). The total hazard quotient (HQ) calculated, based on the formula suggested by the United States Environmental Protection Agency (USEPA), was found to be slightly higher than the acceptable level of 1, indicating that inhalation exposure to particle-bound non-carcinogenic metals of PM10, particularly Cr exposure by children and adults occupying the school environment, was far from negligible.

Elemental characterization and source apportionment of PM10 and PM2.5 in the western coastal area of central Taiwan

This study investigated seasonal variations in PM10 and PM2.5 mass and associated trace metal concentrations in a residential area in proximity to the crude oil refinery plants and industrial parks of central Taiwan. Particle measurements were conducted during winter, spring and summer in 2013 and 2014. Twenty-six trace metals in PM10 and PM2.5 were analyzed using ICP-MS. Multiple approaches of the backward trajectory model, enrichment factor (EF), Lanthanum enrichment and positive matrix fraction (PMF) were used to identify potential sources of particulate metals. Mean concentrations of PM10 in winter, spring and summer were 76.4 ± 22.6, 33.2 ± 9.9 and 37.4 ± 17.0 μg m(-3), respectively, while mean levels of PM2.5 in winter, spring and summer were 47.8 ± 20.0, 23.9 ± 11.2 and 16.3 ± 8.2 μg m(-3), respectively. The concentrations of carcinogenic metals (Ni, As and adjusted Cr(VI)) in PM10 and PM2.5 exceeded the guideline limits published by WHO. The result of EF analysis confirmed that Mo, Sb, Cd, Zn, Mg, Cr, As, Pb, Cu, Ni and V were attributable to anthropogenic emission. PMF analysis demonstrated that trace metals in PM10 and PM2.5 were from the similar sources, such as coal combustion, oil combustion and traffic-related emission, except for soil dust and crustal element emissions only observed in PM10 and secondary aluminum smelter only observed in PM2.5. Considering health-related particulate metals, the traffic-related emission and coal combustion for PM10 and PM2.5, respectively, are important to control for reducing potential carcinogenic risk. The results could aid efforts to clarify the impact of source-specific origins on human health.

Hydrocarbons and heavy metals in fine particulates in oil field air: possible impacts on production of natural silk.

Analyses of fine particulates (PM2.5) from the upper Assam oil fields of India indicated considerable presence of higher hydrocarbons (C22-C35) and heavy metals, Cd, Co, Cr, Cu, Ni, Pb, and Zn. This has raised serious concern for the sustainability of the exotic Muga (Antheraea assama) silk production, which has been a prime activity of a large number of people living in the area. The Muga worm feeds on the leaves of Machilus bombycina plant, and the impacts of air quality on its survival were further investigated by analyzing the leaves of the plant, the plantation soil, and the Muga cocoons. PM2.5 content in the air was much more during the winter due to near calm conditions and high humidity. Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), and gas chromatography-mass spectrometer (GC-MS) analysis of PM2.5 showed the presence of higher alkanes (C22-C35) that could be traced to crude oil. Cr, Ni, and Zn were found in higher concentrations in PM2.5, M. bombycina leaves, and the plantation soil indicating a common origin. The winter has been the best period for production of the silk cocoons, and the unhealthy air during this period is likely to affect the production, which is already reflected in the declining yield of Muga cocoons from the area. SEM and protein analyses of the Muga silk fiber produced in the oil field area have exhibited the deteriorating quality of the silk. This is the first report from India on hydrocarbons and associated metals in PM2.5 collected from an oil field and on their possible effects on production of silk by A. assama.

Source apportionment and water solubility of metals in size segregated particles in urban environments

Metals in atmospheric particulate matter (PM) have been associated with various adverse health effects. Different factors contributing to the characterization and distribution of atmospheric metals in urban environments lead to uncertainty of the understanding of their impact on public health. However, few studies have provided a comprehensive picture of the spatial and seasonal variability of metal concentration, solubility and size distribution, all of which have important roles in their contribution to health effects. This study presents an experimental investigation on the characteristics of metals in PM2.5 and coarse PM in two seasons from four urban sites in Hong Kong. The PM samples were extracted separately with aqua regia and water, and a total of sixteen elements were analyzed using ICP–MS and ICP–OES to determine the size segregated concentration and solubility of metals. The concentrations of major metals were distributed in similar patterns with the same order of magnitude among different urban sites. Source apportionment using Positive Matrix Factorization (PMF) indicated that three sources namely road dust, vehicular exhaust and ship emission are major contributors to the urban atmospheric metal concentrations in Hong Kong with distinctly different profiles between coarse PM and PM2.5 fractions. The individual metals were assigned to different sources, consistent with literature documentation, except potassium emerging with substantial contribution from vehicle exhaust emission. Literature data from past studies on both local and other cities were compared to the results from the present study to investigate the impact of different emission sources and control policies on metal distribution in urban atmosphere. A large variation of solubility among the metals reflected that the majority of metals in PM2.5 were more soluble than those in coarse PM indicating size dependent chemical states of metals. The data from this study provides a rich dataset of metals in urban atmosphere and can be useful for targeted emission control to mitigate the adverse impact of metallic pollution on public health.

Characteristics, sources and health risk assessment of toxic heavy metals in PM2.5 at a megacity of southwest China.

Twenty trace elements in fine particulate matters (i.e., PM2.5) at urban Chengdu, a southwest megacity of China, were determined to study the characteristics, sources and human health risk of particulate toxic heavy metals. This work mainly focused on eight toxic heavy metal elements (As, Cd, Cr, Cu, Mn, Ni, Pb and Zn). The average concentration of PM2.5 was 165.1±84.7µgm(-3) during the study period, significantly exceeding the National Ambient Air Quality Standard (35µgm(-3) in annual average). The particulate heavy metal pollution was very serious in which Cd and As concentrations in PM2.5 significantly surpassed the WHO standard. The enrichment factor values of heavy metals were typically higher than 10, suggesting that they were mainly influenced by anthropogenic sources. More specifically, the Cr, Mn and Ni were slightly enriched, Cu was highly enriched, while As, Cd, Pb and Zn were severely enriched. The results of correlation analysis showed that Cd may come from metallurgy and mechanical manufacturing emissions, and the other metals were predominately influenced by traffic emissions and coal combustion. The results of health risk assessment indicated that As, Mn and Cd would pose a significant non-carcinogenic health risk to both children and adults, while Cr would cause carcinogenic risk. Other toxic heavy metals were within a safe level.