Probabilistic eco-human health risk assessment of heavy metals in soils from Northwestern and Northcentral Nigeria using Monte Carlo simulation

Monte Carlo Health Risk Assessment of Seasonal Potential Toxic Elements in Biota from Oil-impacted Sites in Gokana, Nigeria

Integrated probabilistic risk assessment of potentially toxic elements in urban soils: implications for children’s and birds’ health

Risk-Based Decision Framework for Sustainable Monitoring and Remediation Prioritization of Potentially Toxic Elements in Arid Agricultural Soils

Agricultural soils in arid regions require assessment approaches that separate local element enrichment from actual ecological and human health relevance. Here, a site-prioritization framework is applied to potentially toxic elements (PTEs) in agricultural soils from Onaizah, central Saudi Arabia. The approach combines contamination indices, ecological-risk screening, deterministic health-risk estimates, Monte Carlo resampling, and relative ranking of management priorities. A total of 33 surface-soil samples collected from cultivated farms were examined for As, Co, Cr, Cu, Mn, Ni, Pb, V, and Zn. The measured concentration ranges (mg/kg) were 1–5 (As), 1–12 (Co), 10–53 (Cr), 4–38 (Cu), 107–541 (Mn), 6–54 (Ni), 2–23 (Pb), 8–47 (V), and 11–168 (Zn). Based on their mean concentrations, the investigated elements decreased in the following sequence: Mn > Zn > Cr > Ni > V > Cu > Pb > Co > As. The PN values ranged from 0.127 to 1.339, indicating 27 safe sites, 2 warning-line sites, and 4 slightly polluted sites, mainly controlled by localized Zn enrichment and, in one case, Pb. In contrast, mCd values of 0.099–0.676 indicated nil to very low contamination, while RI values of 2.743–15.701 confirmed low ecological risk across all samples. Non-carcinogenic risk was generally below the threshold of concern, with HI values of 0.204–1.018 for children and 0.024–0.119 for adults. Only one site showed a marginal child HI exceedance, emphasizing localized rather than widespread health concern. Children showed approximately 8.6-fold higher non-carcinogenic risk than adults, with Mn, Cr, As, and V as the main contributors. The total LCR values for As, Cr, and Pb ranged from 7.79 × 10−6 to 4.07 × 10−5 for children and from 3.48 × 10−6 to 1.82 × 10−5 for adults, within the commonly tolerable range of 1 × 10−6 to 1 × 10−4. Chromium was the dominant contributor to LCR. Monte Carlo resampling supported the deterministic risk classification, with only a 3.1% probability of child HI exceeding 1 and no simulated exceedance of the LCR threshold for either children or adults. From the standpoint of sustainable soil management, site 7 should undergo further health-risk assessment, while sites 30 and 33 require source verification and periodic monitoring before any remediation action is considered.

Ecological and human health risk due to heavy metals and trace elements contamination in produced water from basins oil fields in Chad

This study assesses the presence and possible ecological and human health concerns associated with possibly toxic heavy metals and trace elements in produced water collected from the Badila and Benoye oil fields (Doba Basin) and the Ronier oil field (Bongor Basin), in southern Chad. The water samples were analyzed using inductively coupled plasma mass spectrometry. The measured concentrations (µg L− 1) ranged as follows: Cd (0.01–0.11), Co (0.07–9.6), Ni (0.4–3.0), Pb (0.01–27), Cu (3.2–33), As (0.2–86), Zn (0.9–147), Cr (10–823), Ba (12.4–577), Mn (5.8–901), Al (2.1-59710), and Fe (37–875900). The contamination levels were assessed by comparing them to WHO international drinking-water guidelines, rather than by implying direct consumption. The guideline values were exceeded by a substantial number of samples, with Fe (58%), As (42%), Al and Mn (28%), and Pb (28%) exceeding them. The risk quotient approach was employed to conduct an ecological risk assessment, which revealed that the majority of elements were at a low risk. However, Fe was found to have a high potential for ecological concern. Hazard index values of 15 (children) and 10 (adults) were obtained from a hypothetical worst-case exposure scenario (ingestion and dermal contact) in the context of human health risk assessment. These values indicate that there may be potential non-carcinogenic risks under extreme exposure conditions. The cancer risk (CR) values exceeded the permissible threshold, ranging from 4 × 10− 3 to 5 × 10− 3. These results offer baseline data on the quality of produced water in southern Chad; however, they should be interpreted with prudence due to the absence of speciation and dilution considerations and the assumptions regarding exposure pathways. The study underscores the necessity of enhanced monitoring and administration of produced water in oil-producing regions. These findings establish baseline data for produced water quality in southern Chad; nevertheless, the results must be interpreted cautiously due to assumptions about exposure pathways and the absence of speciation and dilution considerations. The study highlights the need for improved monitoring and management of produced water in oil-producing regions.

Probabilistic Health Risk Assessment of Heavy Metals from a Typical Soil–Crop System Around a High-Altitude Industrial Park

The transfer of heavy metals (HMs) from industrial park soils to edible crops is strongly crop-specific; however, these differences have not been considered in probabilistic dietary health risk assessments. This study examined agricultural fields surrounding a high-altitude industrial park in southwestern China, where paired samples of surface soil, Chinese cabbage, and maize were collected and analyzed for Cd, Pb, Cr, Ni, Cu, Zn, Hg, and As. Spearman rank correlation and principal component analysis (PCA) were applied to identify elemental associations and probable sources; bioaccumulation factors (BAFs) were calculated to compare HM transfer and accumulation across the two crops; and Monte Carlo simulation was used to estimate probabilistic dietary health risks across age groups. The results showed that soil HMs in the study area displayed mixed-source characteristics, with marked enrichment of Pb, Cd, and Hg. After multiple comparison correction, only soil Ni showed a significant positive correlation with Ni in maize. Chinese cabbage had a relatively high accumulation capacity for Cd, whereas maize grains showed relatively limited transfer of most HMs, indicating pronounced crop-specific differences. Cd, Pb, Cr, Hg, and As concentrations in Chinese cabbage remained within permissible limits. For health risk, P95 hazard index (HI) values stayed below 1 across all age groups, indicating that non-carcinogenic risk was generally acceptable under the exposure scenarios evaluated; adults, however, carried higher estimated lifetime carcinogenic risk than other age groups. Sensitivity analysis revealed that As and Cd in Chinese cabbage were the dominant contributors to non-carcinogenic and carcinogenic risks, respectively, while the contribution of Cr to risk estimates was highly dependent on its speciation and toxicological parameter assumptions. By combining soil–crop monitoring, bioaccumulation analysis, and probabilistic risk assessment, this study characterizes crop-specific HM transfer patterns and identifies the principal drivers of health risk in industrially influenced agricultural systems, providing a scientific basis for risk-oriented monitoring, food safety management, and the long-term sustainable use of agricultural land in industrial–agricultural interface regions.

Heavy Metal Contamination and Human Health Risk Assessment of Borehole Water at an Academic Campus in Ila-Orangun, Southwestern Nigeria

This study assessed the hydrogeochemistry and health risks associated with groundwater from five existing boreholes sampled once in July, 2024, at Osun State College of Education, Ila-Orangun (OSCEILA), to determine their suitability for drinking and dermal use.  Physicochemical parameters and heavy metal concentrations were analyzed, alongside Water Quality Index (WQI) evaluations and human health risk assessments through ingestion and dermal exposure pathways.  Most water samples exhibited acceptable pH (7.05–7.89), turbidity (0.76–0.82 NTU), and salinity (0.48–0.97 mg/L), with four boreholes classified as “Excellent” by reflecting the quality of the physicochemical parameters incorporated into the WQI indices.  However, Borehole 2 (BH 2) showed elevated electrical conductivity, total dissolved solids, and heavy metal levels, likely influenced by atmospheric deposition and anthropogenic sources such as waste disposal and runoff.  Health risk analysis revealed non-carcinogenic and carcinogenic concerns, especially for children.  While most samples had hazard quotient (HQ) values below the safe threshold (HQ < 1), BH 2exceeded this limit for children (HQ = 1.45), suggesting potential adverse effects.  Carcinogenic risk values for both adults and children far exceeded the acceptable threshold (10⁻⁴), with children at BH 2 facing the highest risk (3.123189).  Although dermal exposure posed comparatively lower risks, values still exceeded safe levels.  Regular monitoring is recommended to mitigate long-term health effects.