Enhanced Gastric/Lung Arsenic Bioaccessibility from Lignite Fly Ashes: Comparing Bioaccessibility Rates with Multiple Environmental Matrices.

Inorganic arsenic (As), a carcinogenic element to humans, is among the most dangerous and flammable substances that coal-burning plants could release. When coal is burned, large portions of arsenic are captured on fly-ash (FA) particles, but it could also contribute significantly to stack emissions of fine fly-ash particles. The aim of this study was to evaluate the oral and respiratory bioaccessibility of arsenic in lignite fly-ash (LFA) samples, and their contribution to total As exposure. Arsenic bioaccessibility fractions via ingestion and inhalation showed significant differences, suggesting the presence of highly soluble As-bearing phases in the studied LFA samples. The bioaccessible As fractions (BAF%) in the simulated gastric fluids (UBM protocol, ISO 17924:2018) showed a range of 45-73%, while the pulmonary bioaccessibility rates in the simulated lung fluid (artificial lung fluid (ALF)) exhibited significantly enhanced levels ranging from 86% to 95%. The obtained arsenic bioaccessibility rates were compared with previous data for multiple environmental matrices such as soil and dust-related materials, revealing that LFA exhibited significantly higher bioaccessibility (%) for the inhalation pathway.

A one-year monitoring of spatiotemporal variations of PM2.5-bound PAHs in Tehran, Iran: Source apportionment, local and regional sources origins and source-specific cancer risk assessment.

PM2.5-bound PAHs were analyzed in a total of 135 daily samples collected during four seasons from 2018 to 2019, at three urban sites in Tehran, Iran. This study aims to investigate spatio-temporal variations, source apportionment, potential local and regional sources contributions and lung cancer risks associated with the 16 US EPA priority PAHs. PM2.5 concentrations ranged from 43.8 to 80.3 µg m-3 with the highest concentrations observed in summer. Total PAHs (TPAHs) concentrations ranged between 24.6 and 38.9 ng m-3. Autumn period exhibited the highest average concentration (48.3 ng m-3) followed by winter (29.5 ng m-3), spring (25.9 ng m-3) and summer (16.1 ng m-3). Five PAHs sources were identified by positive matrix factorization (PMF) analysis: diesel exhaust, unburned petroleum-petrogenic, industrial, gasoline exhaust and coal/biomass combustion-natural gas emissions, accounting for 22.3%, 15.6%, 7.5%, 30.9%, and 23.6% of TPAHs, respectively. Site-specific bivariate polar (BP) and conditional bivariate probability function (CBPF) plots were computed to assess PM2.5 and TPAHs local source locations. CBPF pointed out that TPHAs sources are likely of local origin, showing the highest probability close to the sampling sites associated with low wind speed (<5 m s-1). The potential source contribution function (PSCF) and the concentration weighted trajectory (CWT) models were applied to investigate the long-range transport of PM2.5 and TPAHs. In addition to local sources contributions, Eastern areas were highly related to long-distance transport of PM2.5 and the Western areas showed the highest contribution of the total, medium molecular weight (MMW) (4 rings) and high molecular weight (HMW) (5-6 rings) PAHs. The upper bound of incremental lifetime cancer risk (ILCR) via inhalation exposure to PM2.5-bound PAHs was at a moderate risk level (3.14 × 10-4 to 6.17 × 10-4).

Insights into the anthropogenic load and occupational health risk of heavy metals in floor dust of selected workplaces in an industrial city of Iran.

The levels of Cd, Cr, Cu, Fe, Mn, Pb and Zn were determined in floor dusts from mechanical (MRWs) and battery repairing workshops (BRWs) in Yazd, Iran. The study aimed to evaluate the anthropogenic contribution to the presence of heavy metals (HMs), the possible sources and the related risks that could arise from occupational exposure in the studied workplace microenvironments. Among the analyzed heavy metals, Cu, Pb and Zn exhibited enhanced concentrations in the floor dusts. The EF calculations showed an extremely severe enrichment of HMs, especially for Cd, Cu and Pb, while floor dusts were characterized as "extremely polluted" with regards to those metals. In any case, both EF and Igeo values were significantly higher in the BRWs. These results were also supported by NIPI and PLI values, while contour maps of PLI values in both MRWs and BRWs outlined workshops in N-NE part of Yazd as more impacted compared to other spatial locations. Principal component analysis (PCA) and Pearson's correlation outscored workshops activities as the principal sources of heavy metals. The health risk assessment suggested considerable non-carcinogenic risks regarding Pb in the BRWs which exhibited HQing (mean 2.91) and HI (mean 3.03) values higher than safe level. Regarding carcinogenic risks, CR values for both Cd and Cr were below the safe level (1.0 × 10-6). The occupational exposure to Pb was evaluated through the predicted BLL values, where with averages of 3.33 µg/dl and 21.4 µg/dl for MRWs and BRWs workers, respectively, indicated a severe Pb exposure for BRWs workers.

Concentration, fractionation, and ecological risk assessment of heavy metals and phosphorus in surface sediments from lakes in N. Greece.

The presence of phosphorus (P) and heavy metals (HMs) in surface sediments originating from lakes Volvi, Kerkini, and Doirani (N. Greece), as well as their fractionation patterns, were investigated. No statistically significant differences in total P content were observed among the studied lakes, but notable differences were observed among sampling periods. HM contents in all lakes presented a consistent trend, i.e., Mn > Cr > Zn > Pb > Ni > Cu > Cd, while the highest concentrations were recorded in Lake Kerkini. Most of the HMs exceeded probable effect level value indicating a probable biological effect, while Ni in many cases even exceeded threshold effects level, suggesting severe toxic effects. P was dominantly bound to metal oxides, while a significant shift toward the labile fractions was observed during the spring period. The sum of potentially bioavailable HM fractions followed a downward trend of Mn > Cr > Pb > Zn > Cu > Ni > Cd for most lakes. The geoaccumulation index Igeo values of Cr, Cu, Mn, Ni, and Zn in all lakes characterized the sediments as "unpolluted," while many sediments in lakes Volvi and Kerkini were characterized as "moderately to heavily polluted" with regard to Cd. The descending order of potential ecological risk [Formula: see text] was Cd > Pb > Cu > Ni > Cr > Zn > Mn for all the studied lakes. Ni and Cr presented the highest toxic risk index values in all lake sediments. Finally, the role of mineralogical divergences among lake sediments on the contamination degree was signified.

In vitro assessment of oral and respiratory bioaccesibility of trace elements of environmental concern in Greek fly ashes: Assessing health risk via ingestion and inhalation.

Fly ash engender significant environmental and human health problems due to enhanced contents of potentially harmful trace elements (TrElems). This study aims to evaluate human exposure to TrElems via a combined ingestion (i.e., oral bioaccessibility) and inhalation (i.e., respiratory bioaccessibility) pathway. Five fly ash samples were collected from power plants operating in the main lignite basins of Greece, while the ingestible (<250 µm) and inhalable (<10 µm) particle size fractions were utilized. The Unified Bioaccessibility Method (UBM) was utilized to assess the oral bioaccessibility, while the respiratory bioaccessible fractions were extracted using the Artificial Lysosomal Fluid (ALF). All studied FAs exhibited significantly higher contents in Ba, Cr, Ni, V and Zn. Cadmium was presented relative enriched in the finer size fraction (<10 µm), while Ba, Co, Cr, Cu, Mn, Ni and V were depleted. The UBM-extractable concentrations fluctuated greatly among the studied FAs, while notably lower bioaccessible contents were recorded in the gastrointestinal phase. On the other hand, ALF-extractable concentrations were surprisingly higher than the corresponding UBM-extractable ones in the gastric phase. The oral bioaccessibility of the studied TrElems ranged from 12.5 to 100%, while respiratory bioaccessibility presented high values exceeding 45% on average. A significant effect of fly ash type on human bioaccessibility was revealed. Thus, high-Ca FAs exhibited significantly higher bioaccessibility of the studied TrElems via ingestion, while a relatively higher bioaccessibility via inhalation was observed for high-Si FAs. Regarding non-carcinogenic health risk via ingestion and inhalation, Cr and Co exhibited the highest HQing and HQinh values, however there were significantly lower than safe level (HQ < 1). On the contrary, Cr was the dominant contributor to carcinogenic risk with CR values being well above threshold or even tolerable risk levels.

Magnetic signature, geochemistry, and oral bioaccessibility of "technogenic" metals in contaminated industrial soils from Sindos Industrial Area, Northern Greece.

The objective of this study was to assess the contamination level of potentially harmful elements (PHEs) in industrial soils and how this relates to environmental magnetism. Moreover, emphasis was given to the determination of the potential mobile fractions of typically "technogenic" metals. Therefore, magnetic and geochemical parameters were determined in topsoils (0-20 cm) collected around a chemical industry in Sindos Industrial Area, Thessaloniki, Greece. Soil samples were presented significantly enriched in "technogenic" metals such Cd, Pb, and Zn, while cases of severe soil contamination were observed in sampling sites north-west of the industrial unit. Contents of Cd, Cr, Cu, Ni, Pb, Mo, Sb, Sn, and Zn in soils and pollution load index (PLI) were highly correlated with mass specific magnetic susceptibility (χ lf). Similarly, enrichment factor (EF) and geoaccumulation index (I geo) for "technogenic" Pb and Zn exhibited high positive correlation factors with χ lf. Principal component analysis (PCA) classified PHEs along with the magnetic variable (χ lf) into a common group indicating anthropogenic influence. The water extractable concentrations were substantially low, while the descending order of UBM (Unified BARGE Method) extractable concentrations in the gastric phase was Zn > Pb > As > Cd, yet Cd showed the highest bioaccessibility (almost 95%).

Characterization, heavy metal content and health risk assessment of urban road dusts from the historic center of the city of Thessaloniki, Greece.

In the present study, an investigation of the mineralogy and morphology, the heavy metal content and the health risk of urban road dusts from the second largest city of Greece was conducted. For this reason road dust samples from selected sites within the city core area were collected. No differences were observed in the mineralogy of road dusts coming from different sampling sites, and they were mainly consisted of quartz and calcite, while an elevated amorphous content was detected. Morphologically road dusts presented Ca-rich, Fe-rich and silicates particles with various shapes and sizes. The mean concentrations of Cd, Cr, Cu, Mn, Ni, Pb and Zn in road dust were 1.76, 104.9, 662.3, 336.4, 89.43, 209 and 452.8 µg g-1, respectively. A series of spatial distribution patterns revealed that the hotspot areas were tended to associate with major road junctions and regions with high traffic. Combination of pollution indexes and statistical analyses (correlation analysis, cluster analysis and principal component analysis) revealed that road dusts have a severe influence by anthropogenic activities. In attempt to identify the source of metals through geostatistical and multivariate statistical analyses, it was concluded as follows: Cr, Cu, Fe and Zn mainly originated from tire/break wear and vehicle abrasions, while Cd, Mn and Pb were mainly related to fuel/oil leakage from automobiles along with oil lubricants and vehicle abrasion. Hazard quotient values for children based on total metal concentrations for the road dust ingestion route were lower than safe level (=1). However, the fact that the Hazard Index value for Pb (0.459) which is a particularly toxic metal, was close to safe level, renders essential further investigation in order to provide more reliable characterizations of potential health risks.

Enrichment and oral bioaccessibility of selected trace elements in fly ash-derived magnetic components.

The mineralogy, morphology, and chemical composition of magnetic fractions separated from fly ashes (FAs) originating from Greek lignite-burning power plants was investigated. The oral bioaccessibility of potentially harmful elements (PHEs) from the fly ash magnetic fractions (FAMFs) was also assessed using in vitro gastrointestinal extraction (BARGE Unified Bioaccessibility Method, UBM). The FAMFs isolated were in the range 4.6-18.4%, and their mass specific magnetic susceptibility ranged from 1138 × 10-8 to 1682 × 10-8 m3/kg. XRD analysis and Mossbauer spectroscopy indicated that the dominant iron species were Fe-rich aluminosilicate glass along with magnetite, hematite, and maghemite (in decreasing order). The raw FAs exhibited differences in their chemical composition, indicating the particularity of every lignite basin. The elemental contents of FAMFs presented trends with fly ash type; thus, the FAMFs of high-Ca FAs were enriched in siderophile (Cr, Co, Ni) and lithophile (Cs, Li, Rb) elements and those separated from low-Ca FAs were presented depleted in chalcophile elements. Based on UBM extraction tests, the PHEs were more bioaccessible from the non-magnetic components of the FAs compared to the magnetic ones; however, the bioaccessible fractions estimated for the FAMFs were exceeding 40 % in many cases. Arsenic was found to be significantly bioaccessible (median ~ 80 %) from FAMFs despite the lower As contents in the magnetic fraction.

Study of road dust magnetic phases as the main carrier of potentially harmful trace elements.

Mineralogical and morphological characteristics and heavy metal content of different fractions (bulk, non-magnetic fraction-NMF and magnetic fraction-MF) of road dusts from the city of Thessaloniki (Northern Greece) were investigated. Main emphasis was given on the magnetic phases extracted from these dusts. High magnetic susceptibility values were presented, whereas the MFs content of road dust samples ranged in 2.2-14.7 wt.%. Thermomagnetic analyses indicated that the dominating magnetic carrier in all road dust samples was magnetite, while the presence of hematite and iron sulphides in the investigated samples cannot be excluded. SEM/EDX analyses identified two groups of ferrimagnetic particles: spherules with various surface morphologies and textures and angular/aggregate particles with elevated heavy metal contents, especially Cr. The road dusts (bulk samples) were dominated by calcium, while the mean concentrations of trace elements decreased in the order Zn > Mn > Cu > Pb > Cr > Ni > V > Sn > As > Sb > Co > Mo > W > Cd. MFs exhibited significantly higher concentrations of trace elements compared to NMFs indicating that these potentially harmful elements (PHEs) are preferentially enriched in the MFs and highly associated with the ferrimagnetic particles. Hazard Index (HI) obtained for both adults and children through exposure to bulk dust samples were lower or close to the safe level (=1). On the contrary, the HIs for the magnetic phases indicated that both children and adults are experiencing potential health risk since HI for Cr was significantly higher than safe level. Cancer risk due to road dust exposure is low.