Assessment of Bioaccessibility and Health Risks of Toxic Metals in Roadside Dust of Dhaka City, Bangladesh

Elemental Characterization of Ambient Particulate Matter for a Globally Distributed Monitoring Network: Methodology and Implications

Global ground-level measurements of elements in ambient particulate matter (PM) can provide valuable information to understand the distribution of dust and trace elements, assess health impacts, and investigate emission sources. We use X-ray fluorescence spectroscopy to characterize the elemental composition of PM samples collected from 27 globally distributed sites in the Surface PARTiculate mAtter Network (SPARTAN) over 2019-2023. Consistent protocols are applied to collect all samples and analyze them at one central laboratory, which facilitates comparison across different sites. Multiple quality assurance measures are performed, including applying reference materials that resemble typical PM samples, acceptance testing, and routine quality control. Method detection limits and uncertainties are estimated. Concentrations of dust and trace element oxides (TEO) are determined from the elemental dataset. In addition to sites in arid regions, a moderately high mean dust concentration (6 μg/m3) in PM2.5 is also found in Dhaka (Bangladesh) along with a high average TEO level (6 μg/m3). High carcinogenic risk (>1 cancer case per 100000 adults) from airborne arsenic is observed in Dhaka (Bangladesh), Kanpur (India), and Hanoi (Vietnam). Industries of informal lead-acid battery and e-waste recycling as well as coal-fired brick kilns likely contribute to the elevated trace element concentrations found in Dhaka.

Heavy metals contamination, receptor model-based sources identification, sources-specific ecological and health risks in road dust of a highly developed city

The present study quantified Ni, Cu, Cr, Pb, Cd, As, Zn, and Fe levels in road dust collected from a variety of sites in Tangail, Bangladesh. The goal of this study was to use a matrix factorization model to identify the specific origin of these components and to evaluate the ecological and health hazards associated with each potential origin. The inductively coupled plasma mass spectrometry was used to determine the concentrations of Cu, Ni, Cr, Pb, As, Zn, Cd, and Fe. The average concentrations of these elements were found to be 30.77 ± 8.80, 25.17 ± 6.78, 39.49 ± 12.53, 28.74 ± 7.84, 1.90 ± 0.79, 158.30 ± 28.25, 2.42 ± 0.69, and 18,185.53 ± 4215.61 mg/kg, respectively. Compared to the top continental crust, the mean values of Cu, Pb, Zn, and Cd were 1.09, 1.69, 2.36, and 26.88 times higher, respectively. According to the Nemerow integrated pollution index (NIPI), pollution load index (PLI), Nemerow integrated risk index (NIRI), and potential ecological risk (PER), 84%, 42%, 30%, and 16% of sampling areas, respectively, which possessed severe contamination. PMF model revealed that Cu (43%), Fe (69.3%), and Cd (69.2%) were mainly released from mixed sources, natural sources, and traffic emission, respectively. Traffic emission posed high and moderate risks for modified NIRI and potential ecological risks. The calculated PMF model-based health hazards indicated that the cancer risk value for traffic emission, natural, and mixed sources had been greater than (1.0E-04), indicating probable cancer risks and that traffic emission posed 38% risk to adult males where 37% for both adult females and children.

Indirect Methods to Determine the Risk of Damage to the Health of Firefighters and Children Due to Exposure to Smoke Emission from Burning Wood/Coal in a Controlled Environment

People are constantly exposed to particulate matter and chemicals released during fires. However, there are still few studies on gas and particulate emissions related to exposure to burning firewood and charcoal during forest fires, making it difficult to understand the effects on the health of the population. The objective of this study was to quantify the metal(loid)s present in the smoke from wood and charcoal fires through the deposition of metals in beef topside and pork loin, considering the routes of skin exposure, inhalation, and ingestion, contributing to the understanding of metals in the increase of the risks of cancer and mortality associated with firefighting and children. The concentrations of metals [aluminum (Al), chromium (Cr), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), molybdenum (Mo), vanadium (V), zinc (Zn)] and metalloids arsenic (As) were determined by inductively coupled plasma-mass spectrometry (ICP OES) after microwave digestion. Moreover, we assessed the associated risk regarding the elemental intake of these elements through the smoke, using the hazard quotient (HQ), hazard index (HI), Total Hazard Index (HIt), and carcinogenic risk (CR). All samples had results for HQ and HIt < 1, indicating a non-potential health risk. However, the carcinogenic risks posed by As and Cr via the three exposure pathways (except for inhalation exposure to children and adults, and by Cr via ingestion and inhalation for children and adults) exceeded the standard threshold. In conclusion, continuous exposure of firefighters or children to smoke from fires containing high concentrations of heavy metals such as As and Cr can be harmful to health. The study used animal tissues; thus, new methods must be developed to quantify the concentration of heavy metals deposited in human tissue when humans are exposed to smoke from fires.

Estimation of Pollution Levels and Assessment of Human Health Risks from Potentially Toxic Metals in Road Dust in Mymensingh City of Bangladesh

The assessment of toxic metals pollution in road dust in Mymensingh city, Bangladesh and its impact on the health risk of human exposure to toxic metals, is inadequate. A comprehensive investigation was conducted in different land use areas, i.e., commercial areas (CA), medically facilitated areas (MFA), residential areas (RA), and park areas (PA), to determine levels of Cr (chromium), Mn (manganese), Ni (nickel), Co (cobalt), Cu (copper), Zn (zinc), As (arsenic), Cd (cadmium), and Pb (lead) using inductively coupled plasma mass spectroscopy (ICP-MS). We planned to use different pollution indices, such as the geoaccumulation index (Igeo), contamination factor (CF), degree of contamination (Cdeg), ecological risk (Er), pollution load index (PLI), and enrichment factor (EF), to measure the level of contamination in the road dust of Mymensingh City. The average concentration (mg/kg) ranges of toxic metals in the road dust at different land use areas of Mymensingh City were: Cr (40.8–85.5), Mn (370.7–589.2), Co (6.2–8.7), Ni (22.7–34.2), Cu (29.5–72.2), Zn (236.2–467.1), As (4.9–6.29), Cd (0.32–1.07), and Pb (27.4–81.7), respectively. The CF and PLI results showed that the road dust in these zones was contaminated with toxic metals. The indicator Igeo revealed that CA was found to be ‘moderately to heavily contaminated’ ranked with Zn and Cd. Calculation of EF indicated that Cu, Zn, As, Cd, and Pb were highly enriched, while others were moderately enriched. According to the Cdeg findings, CA, MFA, and RA have very high degrees of contamination (Cdeg ≥ 24), while PA was classified as having a considerable degree of contamination (12 ≤ Cdeg < 24). The Er index showed that only Cd posed a ‘medium potential ecological risk’ to a ‘high ecological potential risk’ in road dust. The most common route of exposure was ingestion. The study indicated that the hazard quotient (HQ) and hazard index (HI) in CA, MFA, RA, and PA were less than one for children and adults, which were at a noncarcinogenic risk. The only exception was for children exposed to manganese (HI > 1) in all land use areas. In the research area, no significant carcinogenic health risk was observed for Cr, Ni, As, Cd, and Pb.