Human health risk assessment of PM2.5-bound heavy metals during a haze season in a semi‑urban agricultural area of Northern Thailand.

Characteristics, Sources, and Health Risks of PM2.5-Bound Heavy Metals in School Environments: A Comparative Study of Two Cities in South China.

The results highlighting the need for continued source control in school environments, with special attention to nonexhaust traffic emissions and industrial combustion, highlight the need for continued source control in school environments.

Assessment of heavy metals and radionuclides pollution in an agro-mining river system: implications for environmental and human health

This study assessed heavy metal (Cu, Ni, Pb, Zn and Cd) and radionuclide (²²⁶Ra, ²³²Th and ⁴⁰K) pollution and associated risks in the Likuyu River system, Tanzania. Surface water and sediments were collected from five sites along a 22.7 km river stretch, while soils and leafy vegetables were sampled from adjacent farms. Heavy metals were analysed by atomic absorption spectrometry and radionuclides by high-purity germanium gamma spectrometry. Risk assessment used contamination factor (CF), geoaccumulation index (Igeo), pollution load index (PLI), bioaccumulation factor (BAF), non-carcinogenic risk, carcinogenic risk (CR), annual effective dose (AED), radium equivalent activity (Raeq), annual ingestion dose (Ding) and excess lifetime cancer risk (ELCR). Heavy metals in river water were below detection limits and complied with WHO drinking-water limits: The Zn, 3–5 mg L⁻¹; Cd, 0.003 mg L⁻¹; Ni, 0.07 mg L⁻¹; Cu, 2.0 mg L⁻¹; and Pb, 0.0135 mg L⁻¹. The Ni in sediments at Sites A and E reached 32.1 ± 26.90 and 35.97 ± 6.51 mg kg⁻¹, respectively, exceeding the threshold effect concentration of 22.7 mg kg⁻¹ but remaining below the probable effect concentration of 48.6 mg kg⁻¹. Pollution indices indicated generally low sediment contamination, with CF values mostly below 1, Igeo values from −5.49 to −0.40, and PLI values from 0.077 to 0.251, although slight Zn enrichment occurred at Site A (CF = 1.14). Soils were weakly polluted, with PLI values of 0.078–0.105; however, Site SOD showed localized Ni enrichment, with CF = 1.577 and Igeo = +0.07, reaching 107.2 ± 1.40 mg kg⁻¹, exceeding the TBS limit of 50 mg kg⁻¹. Bioaccumulation results showed strong Zn uptake in napa cabbage (BAF >12), cowpea (BAF ~8) and okra (BAF ~6), and Pb accumulation in okra (BAF ~6) and cowpea (BAF ~5), whereas Ni and Cd had BAF

Inhalation Bioaccessibility, Pollution Assessment, and Speciation of Heavy Metals in PM2.5RD Road Dust from Urban and Semi-Urban Areas of Pakistan

Ambient exposure to fine particulate matter (PM2.5) remains a critical global public health concern; however, the speciation and bioaccessibility mechanisms of particle-bound heavy metals within the lung environment are still insufficiently understood. In particular, the role of soluble and insoluble metal species in simulated lung fluids requires further clarification. Road dust, a major contributor to PM2.5, contains heavy metals that pose significant inhalation risks, leading to oxidative stress, DNA damage, and systemic toxicity. This study investigated the contamination characteristics, bioaccessibility, pollution level, and speciation of heavy metals in PM2.5-fractionated road dust (PM2.5RD) collected from Karachi (a megacity with >27 million inhabitants) and Shikarpur (a medium-sized city of ~0.3 million) in Pakistan. A grid-based sampling approach was applied across four functional zones (residential, school, hospital, and office), yielding 48 samples. Inhalation bioaccessibility was evaluated using artificial lysosomal fluid (ALF; pH 4.5, 37 °C, 24 h), revealing moderate bioaccessibility of Cr, As, and Pb. Pollution status was assessed using contamination factor (CF), integrated pollution index (IPI), pollution load index (PLI), and potential ecological risk index. Geochemical modeling with PHREEQC 3.0 and Visual MINTEQ 3.1 was employed to simulate metal speciation, release behavior, and mineral saturation states. Overall, this study provides mechanistic insights into speciation-driven toxicity of As, Pb, and Cr in simulated lung environments, offering a scientific basis for improved risk assessment and regulatory strategies for PM2.5-associated metal exposure.

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

Carcinogenic and Non-Carcinogenic Health Risk Assessment of Heavy Metals in Drinking Water near the Batang Masumai River, Indonesia

Contamination of drinking water by heavy metals poses a serious public health concern due to their persistence, bioaccumulation, and potential toxic effects on human health. This study evaluated both carcinogenic and non-carcinogenic health risks associated with seven heavy metals (Hg, Cd, Ni, Fe, Cu, Mn, and Pb) in drinking water sources surrounding the Batang Masumai River, Indonesia. A total of 30 water samples were collected from municipal water supplies (PDAM), refill drinking water depots (AMIU), and groundwater wells, and analyzed using Atomic Absorption Spectrometry (AAS). Health risk assessment was conducted based on the United States Environmental Protection Agency (USEPA) model, including Chronic Daily Intake (CDI), Hazard Quotient (HQ), Hazard Index (HI), and Total Cancer Risk (CRtotal). The results showed that all PDAM samples had HI values below the acceptable limit (HI<1), indicating negligible non-carcinogenic risk. However, HI values exceeding the acceptable threshold were observed in one AMIU sample and one groundwater sample (HI = 1.4), suggesting potential health concerns. In contrast, carcinogenic risk was found to be significantly higher across all water sources, with 90% of PDAM samples and 100% of AMIU and groundwater samples exceeding the acceptable limit (CRtotal>1×10⁻4). The highest carcinogenic risk was detected in groundwater, reaching 4.6×10-3, which is substantially above the recommended safety threshold. The findings reveal that while non-carcinogenic risks are generally within acceptable limits, carcinogenic risks are widespread and pose serious long-term health threats. This study highlights the urgent need for stricter water quality control, continuous monitoring, and targeted mitigation strategies to reduce heavy metal exposure in the study area.

Ecological and human health risks from railway-associated contaminants: a case study of trace metal and PAH pollution along a commuter line in Chittagong, Bangladesh