Trace Metals In Dust Research Articles

Potential hazards and road-source apportionment of toxic trace metals in the dust from residential buildings in typical coal-utilization cities

Toxic trace metals in dust from residential buildings are closely related to human health, but the transmission route and impact degree of dust from coal utilization sources are still unclear. A total of 158 dust samples from different floors of 31 residential buildings in a typical coal-utilization city were collected and analyzed. Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS) were used to analyze chemical speciation and sources of trace elements. Extremely high concentrations of Zn (14,308 mg/kg), Cu (553 mg/kg), Cr (319 mg/kg), Pb (1,208 mg/kg), As (30.8 mg/kg), and Cd (4.18 mg/kg) were found in the dust of residential buildings. Different trace elements tend to be enriched in different floor zones. The concentration of Zn was enriched in the low floor zone, while Cu and Pb were enriched in the middle floor zone, and Cd was enriched in the upper floor zone. The distribution of trace elements was found to be highly correlated between road dust and ground residential building dust, indicating that the input from road dust was the primary factor. Principal component analysis (PCA) combined with particle morphology and mineralogy study demonstrated that coal combustion, road and coal mining dust, and tire wear particles were likely sources of trace elements in dust. Risk assessments showed that As, Pb, and Cr in some samples were found to be harmful to children, particularly in high toxic forms of As (III) and PbO. This study provides systematic evidence for the transmission route and risk assessment of toxic trace metals in dust from residential buildings in coal-utilization cities.

Human health risks associated with trace metals in dust of residential arid areas

Composite dust samples were collected on a monthly basis over a full year from Doha, Qatar. Inductively Coupled Plasma Mass Spectrometry (ICPMS) was used for the determination of total concentrations of Na, K, Mg, Ca, Li, Be, B, V, Cr, Fe, Mn, Co, Ni, Cu, Zn, As, Se, Sr, Cd, Ba, Al, Pb, Ag, TI, U, Sb, Si, Sn, Mo and Bi. A combined approach, merging conventional sampling and analysis with subsequent numerical calculations of the risk of exposure to toxic elements, was employed. For assessment of the health risks associated with the regular exposure to dust, the exposure routes related to the dermal contact and inhalation were considered. Our results indicate that the total non-carcinogenic health risk through exposure to different elements (Hazardous Quotients, HQ's) that are contained in the dust are quite low (well below unity) for both dermal contact and inhalation routes in all months of the year, i.e., there is no risk to the human health. There is no clear explanation for the seasonal variation of metals in the dust in the Qatar area. Several elements in the dust collected in the summertime have higher concentration than in the wintertime. This could be due to the weather conditions and natural depositions. However, the content of several elements (Pb, Zn, Cu, Sn and Li) showed elevation in the wintertime. For dermal exposure, the dominant contribution to the Hazardous Index (HI) comes from thallium (Tl) while for inhalation exposure several comparable contributions are related to Mn, Sb, Si, Ni, and Co. Long-term monitoring strategies are still needed for detailed research on dust pollutants and potential risks.

Human Health Risks Associated with Trace Metals in Dust of Residential Areas in Qatar

Human Health Risks Associated with Trace Metals in Dust of Residential Areas in Qatar

Exploration of the variations and relationships between trace metal enrichment in dust and ecological risks associated with rapid urban expansion

Trace metals in street dust originate from many natural and anthropogenic sources and may directly or indirectly affect daily life and health. Here, the enrichment factor (EF), an efficient parameter to assess the contamination by trace metals, was evaluated and compared in four different zones of the urban area of Nanchang city during different seasons. Results showed that EFs of trace metals have regional seasonal variations. The EF range of Cr, Ni, Cu, Zn, As, Cd and Pb were found to be (0.76–16.38), (0.66–9.06), (1.09–169.58), (1.52–36.16), (0.44–7.17), (2.07–78.38), (0.95–20.94), respectively. These values indicate minimal to significant pollution. The EF values of Zn, Cd and Pb in street dust show very similar variations as their median and mean values of EF are higher in certain zones, and their seasonal variations are similar. The Ni and As results suggest that anthropogenic influences for these elements are not significant. The Ni may be influenced by land use type rather than point sources and As may be attributed to natural sources. The Principal Component Absolute Scores - Multivariate Linear Regression (PCAS-MLR) model was used to identify the types and contributions of trace metal sources. The main sources of trace metals in dust were found to be industrial discharges and traffic emissions. However, the percentages of their contributions have significant regional differences. The relationship between the EF of trace metals and the ecological risk index (ERI) was also investigated, and indicates that seriously polluted areas correspond to high ERI regions. The land use types and characteristics of the source jointly affects the relationship between EFs and ERI.

Growth of marine Vibrio in oligotrophic environments is not stimulated by the addition of inorganic iron

Phytoplankton growth in many high-latitude and equatorial regions of the world ocean is limited by low iron (Fe), while regions of lower nutrient upwelling and higher dust supply such as the subtropical gyres are typically not considered Fe-limited. Recent work which showed that adding Saharan dust leachate promotes blooms of Vibrio bacteria in the North Atlantic Ocean challenges this simple paradigm, because Fe is one of the most prevalent micronutrients in the leachate. We also find that adding high quantities of dust leachate to the North Atlantic near Bermuda stimulates Vibrio growth. However, inorganic Fe alone did not stimulate the growth of Vibrio in any of eleven field experiments in the North Atlantic, central North Pacific, or the coastal Pacific, suggesting that some other growth factor besides Fe is partially or completely responsible for the Vibrio growth response with added dust leachate. We consider the possibility that organic carbon, phosphorous, or other trace-metals in dust might have stimulated Vibrio growth either directly or indirectly. Laboratory culture experiments demonstrate that dust leachate can stimulate the growth of Vibrio even when sufficient Fe is present in the medium. Global modeling suggests that dust fluxes high enough to stimulate Vibrio growth are rare.

Contamination characteristics of trace metals in dust from different levels of roads of a heavily air-polluted city in north China.

Concentrations of eight trace metals (TMs) in road dust (RD) (particles < 25μm) from urban areas of Xinxiang, China, were determined by inductively coupled plasma mass spectrometry. Thegeometric mean concentrations of Zn, Mn, Pb, As, Cu, Cr, Ni and Cd were 489, 350, 114, 101, 60.0, 39.7, 31.6, and 5.1mgkg-1, respectively. When compared with TM levels in background soil, the samples generally display elevated TM concentrations, except for Cr and Mn, and for Cd the enrichment value was 69.6. Spatial variations indicated TMs in RD from park path would have similar sources with main roads, collector streets and bypasses. Average daily exposure doses of the studied TMs were about three orders of magnitude higher for hand-to-mouth ingestion than dermal contact, and the exposure doses for children were 9.33 times higher than that for adults. The decreasing trend of calculated hazard indexes (HI) for the eight elements was As > Pb > Cr > Mn > Cd > Zn > Ni > Cu for both children and adults.