Source apportionment and human health risk assessment of toxic trace elements in urban road dust

Human health risk assessment of heavy metal pollution in airborne dust from Zakho City, Iraq

Spatial distribution and health risk implications of elemental hazard quotients in selected Nigerian cities

The disease burden associated with air pollution is now comparable to that of other major global health threats, including poor nutrition and tobacco use. This study employed the gravitational settling method to collect airborne particles in selected Nigerian cities. The cities include; Benin, Kano, Abuja, Lagos, Enugu, and Calabar. Airborne particles were allowed to settle naturally into containers fitted with funnels and placed outdoors at various sub-locations within each State. Sampling was conducted over a nine-month period from January to September 2023. The collected sediments were analyzed spectroscopically using a UV Visible (UV-VIS) Spectrophotometer CE 1101 to determine concentrations of cadmium (Cd), nickel (Ni), lead (Pb), and manganese (Mn). Results revealed that hazard quotient (HQ) values for all analyzed metals exceeded the recommended safe limit of 1 across all locations. In Benin City, nickel and lead recorded HQ values of 5.5 and 4.0, respectively. Enugu showed particularly elevated levels, with manganese (Mn) at HQ 16 and lead (Pb) at HQ 5, attributed to industrialization and vehicular activities. In Kano, HQ values for lead (Pb) and nickel (Ni) were 8.0 and 4.9, respectively. Abuja recorded HQ values of 6.0 for lead (Pb) and 4.9 for nickel (Ni), likely linked to recycling and agricultural activities. Lagos and Calabar also exhibited elevated HQ values, particularly for lead and nickel. Elevated exposure to these toxic elements can pose potential health risks, including neurological, respiratory, and allergic effects, to exposed populations.

Trace Metal Concentrations in Rainwater, Sources, and Health Risks: A Case Study of Hanoi, Vietnam

Atmospheric wet deposition, where pollutants, including metals, are washed from the atmosphere by rain, is a significant concern, particularly in urban and industrial areas, given the risks to human and ecosystem health. This study investigated the concentrations, sources, and potential health risk of 10 metals in 102 rainwater samples collected in Hanoi city during the period 2023–2025. The results showed that zinc-(Zn) was the most abundant metal, followed by iron-(Fe), manganese-(Mn), nickel-(Ni), copper-(Cu), lead-(Pb), chromium-(Cr), arsenic-(As), cadmium-(Cd), and mercury-(Hg). Although the mean values of these 10 metals were within the limits of the Vietnam technical regulation for drinking water, the maximal values of Fe, Mn and Pb were higher than the permissible values. Single-factor pollution index (Pi), and Nemerow pollution index (PN) showed a low pollution level of rainwater. Both the hazard index (HI) and the total carcinogenic risk demonstrated low potential health risks. Enrichment factor (EF) values revealed strong anthropogenic impacts on three metals (Hg, Cd, and Zn), whereas the remaining metals were from both natural and anthropogenic sources. Increasing population, urbanization, and industrial production, with the combustion of fossil fuel, domestic and agricultural waste, and urban construction, are probably major sources. Our results provide scientific evidence for policy-makers in environmental and ecosystem protection and provide data for the estimation of metal loads from wet deposition at regional and global scales. 10 rainwater metal concentrations were measured in Hanoi city in 2023–2025. Concentrations decreased in the order: Zn > Fe > Mn > Ni > Cu > Pb ~ Cr > As > Cd > Hg. Maximal values of Fe, Mn and Pb exceeded the limits for drinking water. Pi and PN indices revealed low pollution levels, whereas HI and total CR demonstrated low potential health risks. Hg, Cd, and Zn originated from anthropogenic activities, whereas the remaining metals were from both natural and anthropogenic sources. 10 rainwater metal concentrations were measured in Hanoi city in 2023–2025. Concentrations decreased in the order: Zn > Fe > Mn > Ni > Cu > Pb ~ Cr > As > Cd > Hg. Maximal values of Fe, Mn and Pb exceeded the limits for drinking water. Pi and PN indices revealed low pollution levels, whereas HI and total CR demonstrated low potential health risks. Hg, Cd, and Zn originated from anthropogenic activities, whereas the remaining metals were from both natural and anthropogenic sources.

Integrated Assessment of Heavy Metal Accumulation in Urban Trees and Soils and Associated Non-carcinogenic Health Risks in Sabzevar, Iran

Elemental composition of indoor dust and health risk assessment in preschools located in a seasonal haze-affected area: Lampang Province, Thailand

This study investigated trace element contamination, source characteristics, and associated health risks of indoor dust collected from 22 preschools across six districts of haze-affected Lampang Province, Thailand. Dust samples from urban, coal power plant, sub-urban, and rural areas were analyzed for As, Cr, Ni, Pb, Cu, Fe, Mn, Zn, and K using ICP-OES following acid digestion. Contamination levels were evaluated using the enrichment factor (EF), geo-accumulation index (Igeo), and potential ecological risk index (RI), while human health risks were assessed using non-carcinogenic (HQ, HI) and carcinogenic (CR, TCR) models. Fe, K, Zn, and Mn were the dominant elements, with Zn showing moderate contamination and strong anthropogenic influence, particularly from traffic emissions and biomass burning. Source apportionment indicated mixed contributions from soil dust, industrial activities, and combustion processes. Ecological risk remained low across all sites (RI < 150). Non-carcinogenic risks were negligible (HI < 1), although children were more susceptible than adults. Carcinogenic risks for As, Cr, and Ni through both ingestion and inhalation pathways were within acceptable limits (10-6 to 10-4), with ingestion representing the dominant exposure pathway. Overall, indoor dust posed low ecological and health risks; however, continued monitoring is recommended due to potential long-term exposure effects on children.

Geoinformatics-driven mapping of heavy metal contamination and associated health risks.

Potable groundwater of Ludhiana district in Punjab, India, has become a significant source for water consumption due to the growing contamination of surface water sources. A total of 60 groundwater samples were taken at 13 blocks and concentration of the heavy metals such as Arsenic, Lead, Selenium, Chromium and Cadmium was determined using Inductively Coupled Plasma Mass Spectroscopy and Ion Chromatography. Carcinogenic and non-carcinogenic risks were assessed using hazard quotient (HQ), hazard index (HI) incremental lifetime cancer risk (ILCR). The results showed that district-wide carcinogenic risks across Ludhiana, induced primarily by As with contributions from Cr and Pb contamination in groundwater. No non-carcinogenic risk was identified due to iron (Fe) and selenium (Se). Pb exceeded BIS (1991) limits in 45% of samples, followed by Cd (20%), Se (11.67%), and As (3.33%). Therefore, the harmful effects caused by groundwater pollution must be taken seriously and addressed promptly. These findings confirmed that groundwater containing As, Cr, and Pb above permissible values is unsuitable for consumption posing serious health hazards to the population of study area.