Assessment of crustal element and trace metal concentrations in atmospheric particulate matter over a coastal city in the Eastern Arabian Sea

Chemical characteristics, morphology and source apportionment of PM10 over National Capital Region (NCR) of India

The present study frames the physico-chemical characteristics and the source apportionment of PM10 over National Capital Region (NCR) of India using the receptor model's Positive Matrix Factorization (PMF) and Principal Momponent Mnalysis/Absolute Principal Component Score-Multilinear Regression (PCA/APCS-MLR). The annual average mass concentration of PM10 over the urban site of Faridabad, IGDTUW-Delhi and CSIR-NPL of NCR-Delhi were observed to be 195 ± 121, 275 ± 141 and 209 ± 81 µg m-3, respectively. Carbonaceous species (organic carbon (OC), elemental carbon (EC) and water-soluble organic carbon (WSOC)), elemental constituents (Al, Ti, Na, Mg, Cr, Mn, Fe, Cu, Zn, Br, Ba, Mo Pb) and water-soluble ionic components (F-, Cl-, SO42-, NO3-, NH4+, Na+, K+, Mg2+, Ca2+) of PM10 were entrenched to the receptor models to comprehend the possible sources of PM10. The PMF assorted sources over Faridabad were soil dust (SD 15%), industrial emission (IE 14%), vehicular emission (VE 19%), secondary aerosol (SA 23%) and sodium magnesium salt (SMS 17%). For IGDTUW-Delhi, the sources were SD (16%), VE (19%), SMS (18%), IE (11%), SA (27%) and VE + IE (9%). Emission sources like SD (24%), IE (8%), SMS (20%), VE + IE (12%), VE (15%) and SA + BB (21%) were extracted over CSIR-NPL, New Delhi, which are quite obvious towards the sites. PCA/APCS-MLR quantified the similar sources with varied percentage contribution. Additionally, catalogue the Conditional Bivariate Probability Function (CBPF) for directionality of the local source regions and morphology as spherical, flocculent and irregular were imaged using a Field Emission-Scanning Electron Microscope (FE-SEM).

Occurrence of 8 trace elements in Rhizoma Cibotii from China and exposure assessment

The contamination of trace elements in Chinese edible herbs has attracted worldwide concern over the world. The objective of the present study was to investigate the occurrence and exposure assessment of eight trace elements in Rhizoma Cibotii from China. For this purpose, the method of inductively coupled plasma mass spectrometry was employed to detect the contamination levels of target trace elements in 58 Rhizoma Cibotii samples. The results demonstrated that the trace elements of Cr, Ni, Cu, Zn, and Pb were detected in all analyzed samples; the occurrence frequencies of As, Se, and Cd were 98.3%, 96.6%, and 98.3%, respectively. The highest mean levels were found in Zn (17.32 mg/kg), followed by Pb (8.50 mg/kg) and Cu (3.51 mg/kg). For a further step, one-way ANOVA was used to compare the difference of eight elements levels among groups, and Pearson's correlation analysis was used to explore the correlation between elements in Rhizoma Cibotii. A strong positive correlation between Zn and Cd was observed by Pearson's correlation analysis, which indicated that the possible presence of Cd contamination in Rhizoma Cibotii. Based on the contamination levels, the mean exposure of individual element and the health risks of eight trace elements in Rhizoma Cibotii were estimated by health risk assessment models. The calculated HQ values were less than 1, indicating that the contamination of trace elements in Rhizoma Cibotii did not pose significant health risks to human. In conclusion, the study provided baseline information on the contamination levels of trace elements in Rhizoma Cibotii. Moreover, it is necessary to monitor the trend of trace elements levels in Rhizoma Cibotii, which will be useful for ingredient control and human health protection.

Risk assessment and management of PM2.5-bound heavy metals in the urban area of Kitakyushu, Japan

The sampling campaign of PM_2.5 was carried out in Kitakyushu City on the western edge of Japan from 2013 to 2019, and 29 heavy metals loaded in PM_2.5 were measured in this study. During the whole sampling period, the PM_2.5 mass concentration ranged from 6.3 μg·m^-3 to 57.5 μg·m^-3, with a median value of 21.3 μg·m^-3, and the sum concentration of heavy metals only accounted for 3%. According to the enrichment factor (EF) and geo-accumulation index (Igeo) analysis, it can be known that Se, Mo, Pb, As, Zn, W, Sb, Cu, V, Cr, Ni, and Cs were mainly from anthropogenic sources, which had EF values larger than 10 and Igeo values larger than 0. The comprehensive ecological risk index for these 12 anthropogenic metals was far greater than 600. This large index showed severe metal pollution and very high ecological risk in the urban area of Kitakyushu, Japan, which should be paid great attention. The human health assessment result further revealed that children living at the sampling site faced severe non-carcinogenic risk (HI = 7.8) and moderate carcinogenic risk (CR = 1.2 × 10^-4), and oral ingestion was basically the most important exposure pathway, followed by dermal contact and inhalation. The priority control metals included Mo, Se, As, Pb, Sb, and Cr; moreover, the concentration-weighted trajectory analysis (CWT) indicated that Mo, Sb, and Cr were from ship emissions because some shipping routes around the Kyushu area were identified as their potential pollution source regions, while Se, As, and Pb were carried by the air masses from the Asian landmass. Overall, although the PM_2.5 concentration in the urban area of Kitakyushu, Japan was not high, the heavy metal risk cannot be overlooked; it is necessary to strengthen the source control of high-risk metals and raise public protection awareness.

Health impact assessment from exposure to trace metals present in atmospheric PM10 at Ahmedabad, a big city in western India

Many toxicological studies revealed the deleterious effects on human health induced by trace metals in ambient particulate matter (PM). This study reports the season-dependent water-soluble and total metal mass in PM₁₀ collected simultaneously over five microenvironments in a semi-arid urban region, Ahmedabad, located in western India. The mineral dust fraction in PM₁₀ over Bapunagar, Narol, Paldi, Income Tax, and Science City was estimated to be around 39, 45, 47, 44, and 31% during summer (May-June 2017) and 24, 55, 28, 27, and 28% during winter (December 2017-January 2018), respectively, corroborating mineral dust is perennial in the air over Ahmedabad. The PM_2.5/PM₁₀ mass ratios over all the sites were higher during winter (40-60%) as compared to those during summer (30-40%), indicating the contribution from the anthropogenic sources to PM mass. Among the metals monitored, the estimated considerable amount of high masses of Zn, Cu, Ni, Cd, and Sb during winter can be ascribed to the anthropogenic inputs based on the estimated enrichment factors (EF). In contrast to the crustal source, these metals might have been possibly emitted from several other man-made sources, which were found to be more water-soluble during both seasons. As per the standards of incremental excess lifetime cancer risk (IELCR), it is estimated that the atmospheric mass concentration of carcinogenic metals such as Cr, Co, and As was higher in all these sites, whereas the metals such as Pb, Ni, and Cd are also found over the industrial site (Narol) in addition to the above-said metals. Notably, people are highly susceptible to these metals, leading to the potential risk of cancer during both seasons.

Geochemical characteristics of trace elements in size-resolved coastal urban aerosols associated with distinct air masses over tropical peninsular India: Size distributions and source apportionment

Trace elements in atmospheric particulate matter play a significant role in air quality, health and biogeochemical cycles. The present study reports on geochemical characteristics of size-resolved trace elements in PM₁₀ aerosols collected under different air masses over a coastal urban location in peninsular India. A contrast in elemental distribution was observed for the particle size above 7.0 μm and below 1.1 μm under the influence of northeasterly air masses as characterized by Al > Fe > Zn and Fe > Al > Zn, respectively. The concentrations of the crustal elements (Al, Fe, Ti, P, Ba, Co) were high and illustrated by a unimodal size distribution with a peak in coarse mode (>2.0 μm) during northwesterly air masses. On the other hand, combustion-derived metals (Cu, Zn, Cd, Sb, and Pb) were maximized under northeasterly air masses, characterized by unimodal size distribution with a peak in fine mode (<2.0 μm). The enrichment factor (EF) analysis reveals the contribution of anthropogenic emissions to Cd, Sb, Pb, Zn, Cu, Cr, Ni, As, and Sn metals, particularly to the high enrichment of trace metals in fine mode. These results suggest that crustal emissions are major sources of trace metals in coarse mode aerosols; whereas combustion derived anthropogenic emissions contribute to the fine mode aerosols. The positive matrix factorization (PMF) analysis revealed that crustal sources (52-90%) were most abundant for particles >7.0 μm, whereas combustion related emissions such as vehicular and traffic sources are predominant for particles <1.1 μm. The present study demonstrates that trace metals in coastal urban aerosols are affected by changes in emission sources/strengths and regional transport of air masses originated from the northeasterly and northwesterly parts of the tropical Indian subcontinent.

Geochemical characterization of modern aeolian dust over the Northeastern Arabian Sea: Implication for dust transport in the Arabian Sea

The Arabian Sea, one of the most biologically productive oceanic regions, receive significant amount of nutrients through aeolian dust deposition which have potential to modulate surface water biogeochemical processes. Identification of dust sources is important to assess role of dust deposition to surface water biogeochemistry. Here we report geochemical characteristics (major elements and trace metals composition, clay mineralogy and radiogenic isotopes of Sr and Nd) of aeolian dust, derived from dust storms in Middle East and South West Asia, to decipher its sources and possible transport pathways over the Arabian Sea. Twelve bulk aerosol samples were collected, during dusty period, at a coastal station (Goa; 15.4^o N, 73.8^o E) located in the Northeastern Arabian Sea, spanning over three years in different seasons. A preliminary estimation of sources for dust storms was done using satellite imagery and air mass back trajectory analyses. Major element and trace metal compositions of storm derived dust samples indicate insignificant contribution from anthropogenic sources. Illite and chlorite are major clay minerals found in all dust samples, however, high palygorskite content were observed for dust sourced from the Arabian Peninsula. A more uniform Sr-Nd signature is found for those derived from Arabia, however, highly variable Sr-Nd isotope signatures were observed for those derived from the South West Asia (Iran and Makran coast). The reported comprehensive data set on geochemical characteristics of mineral dust, is the first attempt that provides important information to understand present and past dust emission and deposition over the Arabian Sea.