Investigating the risk of heavy metal contamination in an industrial and a non-industrial zone in Gazipur district, Bangladesh

Evaluation and Origin Studies of Heavy Metals in Soils Around Traditional Mining Regions in the Northwest Guizhou District

Heavy metal contamination in soil has emerged as a critical environmental issue. However, research specifically addressing the distribution, pollution levels, and source analysis of heavy metals in lead-zinc mining areas remains limited. To assess the extent of soil heavy metal pollution around a lead-zinc mine in northwest Guizhou and to perform a quantitative source analysis, this study collected 56 surface soil samples and 14 samples from two different depths. The concentrations and chemical forms of Cd, Pb, Cr, Cu, Ni, and Zn were measured. Pollution levels were evaluated using the geoaccumulation index (Igeo) and the secondary-to-primary phase ratio (RSP). Sources were identified through correlation analysis, principal component analysis, and positive matrix factorization (PMF). The results demonstrated that: (1) The average concentrations of Pb, Zn, Cd, Cr, Cu, and Ni were all below Guizhou’s soil background levels. While Cd and Pb reached maximum values close to background levels, their coefficients of variation were 66.56%, 413.84%, 123.04%, 195.69%, 319.98%, and 373.41%, respectively, indicating high variability and significant anthropogenic influence. Elevated levels of Cd, Cu, Pb, and Zn are closely aligned with mining locations. (2) The Igeo evaluations indicated that most areas were unpolluted; however, the RSP method revealed that 5% and 4% of sites were slightly polluted by Pb and Zn, respectively, with 4% showing slight Cd contamination, and 2% experiencing moderate to severe pollution. (3) PMF source apportionment identified five main sources: 63.7% of Cr from agriculture, 72.3% of Cd from atmospheric deposition, 59.1% of Zn and 41.9% of Ni from wastewater discharge, 52.9% of Cu, 45.4% of Ni, and 36.2% of Cr from traffic emissions, and 79.9% of Pb from mining activities. The study concluded that overall heavy metal pollution was slight, though Cd, Pb, and Zn were notably influenced by mining and associated human activities. Different sources contributed distinctly: mining primarily impacted Pb, while agriculture, atmospheric deposition, and wastewater discharge mainly affected Cr, Cd, and Zn accumulation, respectively. These findings offer a scientific basis for soil pollution prevention, control, and ecological risk management in the region.

Appraisal of contamination levels, pollution sources and health risks of trace metals in the groundwater of Southern Pothohar, Pakistan

The contamination of groundwater by trace metals is a significant concern on global scale as it presents direct and indirect hazards to the ecosystem and human health. However, only limited studies have focused on the risks of trace metals’ contamination in major agronomical areas of Pakistan. The present investigation was designed to evaluate the concentrations of selected metals (Mg, K, Ca, Na, Sr, Ag, Li, Zn, Mn, Fe, Co, Cu, Cd, Cr, Pb and Ni) and physicochemical characteristics (EC, pH, TDS, TH, TA, and Cl−) in the groundwater of Southern Pothohar region of Pakistan. Significant seasonal variations in the metal concentrations were detected; average levels of Ni (0.206 mg/L), Cr (0.085 mg/L), Cu (0.038 mg/L), Mn (0.029 mg/L), Ag (0.026 mg/L), and Cd (0.017 mg/L) were comparatively higher in summer, whereas mean values of Ca (9.210 mg/L), Sr (2.181 mg/L), Co (0.195 mg/L), Li (0.033 mg/L), and Zn (0.025 mg/L) showed relatively elevated concentrations in winter. Average contents of Co, Cr, Cd, Pb and Ni were observed to surpass the permissible limits in 37–99% of the samples established by national and international standards. Multivariate statistical analyses revealed that groundwater contamination was predominantly influenced by anthropogenic sources (mostly originating from agricultural waste, domestic waste, combustion processes, industrial effluents and automobile emissions). The Irrigation Water Quality Index (IWQI) value demonstrated that the groundwater is highly suitable for irrigation. Health risk estimation revealed that noncancer risk for Cd, Cr Ni, and Li surpassed the safe limit (HQing > 1) for adults while Pb and Co exceeded the safe limit (1.0) for children and adults in both seasons. Overall, the study indicated more susceptibility of children than adults to noncarcinogenic risks. Additionally, the carcinogenic health risks for nickel, chromium, lead, and cadmium notably exceeded the acceptable threshold of 1.0 × 10− 06, indicating significant lifetime cancer risk linked to these metals in groundwater. The health concerns warrant urgent attention, and immediate actions are necessary to safeguard and improve the groundwater quality in the studied region.

Assessment of heavy metal and bacterial contamination in groundwater resources in Dong Nai Province, Vietnam

Dong Nai Province, located in southeastern Vietnam, has experienced rapid industrial and agricultural development, accompanied by increasing pressure on groundwater resources. Excessive groundwater extraction raises concerns regarding water quality, agricultural sustainability, and public health. This study assessed groundwater contamination by nitrate, selected heavy metals, and bacterial indicators across the province. A total of 55 ground-water samples were analyzed for nitrate, arsenic (As), cadmium (Cd), mercury (Hg), lead (Pb), total coliforms, and Escherichia coli ( E. coli ). The mean nitrate concentration was 18.02 mg/L, with the highest levels observed in Bien Hoa City. Lead contamination was widespread, exceeding drinking-water standards at several locations, while elevated As and Cd concentrations were detected only at a limited number of sites. Bacterial contamination, indicated by total coliforms and E. coli , was detected in multiple districts, particularly in Long Khanh. Although the results primarily indicate associations rather than direct causal relationships, they highlight potential risks to groundwater used for domestic supply and agricultural irrigation. The findings provide evidence to support im - proved groundwater monitoring, agricultural water management, and policy development aimed at safeguarding rural livelihoods and sustainable agricultural development in Dong Nai Province.

 Detection of Air Pollution with Lead, Cadmium, and Zinc in Selected Industrial Areas of Baghdad

The objectives of this study are to investigate the concentrations of heavy metals in two selected industrial areas. Airborne heavy metal pollution represents a persistent environmental and public health problem in rapidly urbanizing cities. This research assesses the seasonal distribution of lead (Pb), cadmium (Cd), and zinc (Zn) associated with airborne particulate matter in two selected industrial areas including Al Bayaa on the Karkh side and Al Shurta Tunnel on the Rusafa side of Baghdad and a rural control site. Samples of air were collected during four seasons autumn, winter, spring, and summer and then analyzed using atomic absorption spectrometry AAS. The results revealed pronounced seasonal differences, Lead concentrations varied across the four seasons, with the highest concentration recorded in the summer at the Al Shurta Tunnel, reaching 5.8 µg/m³, while the lowest concentration was recorded in the same area during the winter at 0.0185 µg/m³. Cadmium concentrations were recorded at their lowest value of 0.0294 µg/m³ in winter in the police tunnel and at their highest concentration of 4 µg/m³ in the Al Bayyaa area in spring. As for zinc, its concentrations ranged between 2.257 µg/m³ and 43.8 µg/m³ in the winter and spring, respectively, in the police tunnel area. In general Cd levels remained low but exhibited episodic increases, particularly in Al Bayaa. Although most measured concentrations were below commonly cited health-based guideline values, the consistent detection of heavy metals highlights their persistence in Baghdad industrial atmosphere. These findings provide baseline data for Baghdad and emphasize the necessity for continuous monitoring and strengthened air quality management strategies.

Heavy Metal Contamination in Arid Coastal Saudi Arabia: An Integrated Pollution-Index and Multivariate Approach Toward Environmental Sustainability

Potentially Toxic Elements (PTEs) contamination of the soil is a global environmental problem, which can seriously affect the ecosystem, agricultural development, and human health. To evaluate the degree of potentially toxic metal contamination, 32 soil samples were collected from different sites in the Yanbu and Khulais areas of Saudi Arabia to analyze eight PTEs (Co, Cr, Cu, Fe, Ni, Pb, V, and Zn). The contamination indices used including the Geo-accumulation Index (Igeo), Enrichment Factor (EF), Contamination Factor (CF), and Pollution Load Index (PLI), as well as Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) for source identification. Because metals taken up from soil can move along the soil-to-plant pathway into crops, characterizing the degree and likely origin of potentially toxic metal enrichment in agricultural soil is a necessary first step for any subsequent land-management or food-safety assessment, particularly in a country that imports the majority of its food. The results of PCA and HCA indicate that the basement rocks of Arabian Shield-associated minerals are a plausible primary source of these potentially toxic elements. The mean EF values of the PTEs in decreasing order are as follows: Co (0.93) > Ni (0.92) > Cu (0.80) > Zn (0.74) > V (0.65) > Cr (0.59) > Pb (0.27). This implies that the soils in the study area are not enriched or only slightly enriched with PTEs. According to the geoaccumulation index values, nearly every PTE was classified as practically unpolluted (Igeo < 0), the exception being Ni, which reached the unpolluted-to-moderately-polluted class (Igeo ≥ 0) at four Khulais sites. The CF and PLI values indicate that the soil is unpolluted on average. In summary, the combined pollution-index and multivariate framework offers a practical geochemical screening tool for this arid coastal region; monitoring soil quality in this way is a useful contribution to sustainable land management in water- and land-limited environments.

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