Health Risk Assessment of Heavy Metals in Groundwater of Hainan Island Using the Monte Carlo Simulation Coupled with the APCS/MLR Model

Pollution characteristics and source apportionment of heavy metal(loid)s in soil and groundwater of a retired industrial park

Heavy metal(loid)s (HMs) pollution has become a common and complex problem in industrial parks due to rapid industrialization and urbanization. Here, soil and groundwater were sampled from a retired industrial park to investigate the pollution characteristics of HMs. Results show that Ni, Pb, Cr, Zn, Cd, and Cu were the typical HMs in the soil. Source analysis with the positive matrix factorization model indicates that HMs in the topsoil stemmed from industrial activities, traffic emission, and natural source, and the groundwater HMs originated from industrial activities, groundwater-soil interaction, groundwater-rock interaction, and atmosphere deposition. The sequential extraction of soil HMs reveals that As and Hg were mainly distributed in the residue fraction, while Ni, Pb, Cr, Zn, Cd, and Cu mainly existed in the mobile fraction. Most HMs either in the total concentration or in the bioavailable fraction preferred to retain in soil as indicated by their high soil-water partitioning coefficients (Kd), and the Kd values were correlated with soil pH, groundwater redox potential, and dissolved oxygen. The relative stable soil-groundwater circumstance and the low active fraction contents limited the vertical migration of soil HMs and their release to groundwater. These findings increase our knowledge about HMs pollution characteristics of traditional industrial parks and provide a protocol for HMs pollution scrutinizing in large zones.

Concentration of steroid hormones in sediment of surface water resources in China: systematic review and meta-analysis with ecological risk assessment

The risk quotient (RQ) related to Estrone (E1), 17β-E2 (E2), Estriol (E3) and 17α-ethynylestradiol (EE2) in sediment of water resources in China was calculated using Monte Carlo Simulation (MCS) method. Fifty-four papers with 64 data-reports included in our study. The rank order of steroid hormones in sediment based on log-normal distribution in MCS was E1 (3.75 ng/g dw) > E3 (1.53 ng/g dw) > EE2 (1.38 ng/g dw) > E2 (1.17 ng/g dw). According to results, concentration of steroid hormones including E1, E2 and E3 in sediment of Erhai lake, northern Taihu lake and Dianchi river was higher than other locations. The rank order of steroid hormones based on percentage high risk (RQ > 1) was EE2 (87.00%) > E1 (70.00%) > E2 (62.99%) > E3 (11.11%). Hence, contamination control plans for steroid hormones in sediment of water resources in China should be conducted continuously.

Steroid hormones in surface water resources in China: systematic review and meta-analysis and probabilistic ecological risk assessment

A Search was conducted in international databases including Scopus, PubMed, Embase, and Web of Science from 10 January 2005 to 15 January 2023. The risk quotient (RQ) of Estrone (E1), 17β-E2 (E2), and Estriol (E3) on the surface water resources of China was calculated by Monte Carlo Simulation (MCS) technique. The rank order of steroid hormones based on pooled (weighted average) concentration in surface water was E3 (2.15 ng/l) > E2 (2.01 ng/l) > E1 (1.385 ng/l). The concentration of E1 in Dianchi lake (236.50.00 ng/l), 17β-E2 in Licun river (78.50 ng/l), and E3 in Dianchi lake (103.1 ng/l) were higher than in other surface water resources in China. RQ related to E1, 17β-E2 and E3 in 68.00%, 88.89% and 3.92% of surface water resources were high ecological risk, respectively. Therefore, carrying out source control plans for steroid hormones in surface water sources should be conducted continuously.

Determination of high-risk factors and related spatially influencing variables of heavy metals in groundwater

Identifying high-risk factors (heavy metals (HMs) and pollution sources) by coupling receptor models and health risk assessment model (HRA) is a novel approach within the field of risk assessment. However, this coupled model ignores the contribution of spatial differentiation to high-risk factors, resulting in the assessment being subjective. Taking Dongting Plain (DTP) as an example, a coupling framework by jointly using the positive matrix factorization model (PMF), HRA, Monte Carlo simulation, and geo-detector was developed, aiming to identify high-risk factors in groundwater, and further explore key environmental variables influencing the spatial heterogeneity of high-risk factors. The results showed that at least 82.86 % of non-carcinogenic risks and 97.41 % of carcinogenic risks were unacceptable for people of all ages, especially infants and children. According to the relationships among HMs, pollution sources, and health risks, As and natural sources were defined as high-risk HMs and sources, respectively. The interactions among Holocene thickness, oxidation-reduction potential, and dissolved organic carbon emerged as the primary drivers of spatial variability in high-risk factors, with their combined explanatory power reaching up to 74%. This proposed framework provides a scientific reference for future studies and a practical reference for environmental authorities in developing effective pollution management measures.

Entropy-weighted water quality index, hydrogeochemistry, and Monte Carlo simulation of source-specific health risks of groundwater in the Morava River plain (Serbia)

Population growth, urbanization, industry, floods, and agriculture globally degrade groundwater in river plains, necessitating action for its quality assessment and management. Hence, a comprehensive methodology, including hydrogeochemical facies (Piper, Gibbs), irrigation indices (SAR, Wilcox), entropy-weighted water quality index (EWQI), positive matrix factorization (PMF), and Monte Carlo simulation of source-specific health risks was used in this study to analyze groundwater in the Morava river plain (Serbia). The results revealed a prevalent Ca-Mg-HCO3 groundwater type, influenced by water-rock interactions. Although groundwater was found suitable for irrigation, only 66.7 % of the samples were considered drinkable. Agricultural activities, natural processes, and municipal wastewater were identified as primary pollution sources. The incremental lifetime cancer risk (ILCR) and hazard index (HI) threshold exceedance for adults and children ranged from 8.5 % to 39 % of the samples, with arsenic identified as the most risk-contributing contaminant. These findings provide valuable insights for researchers studying groundwater vulnerability in river plains.

Health risk assessment of heavy metals based on source analysis and Monte Carlo in the downstream basin of the Zishui

In this study, stone coal mines in the lower reaches of the Zijiang River were adopted as the research object. To analyze the spatial distribution, sources, and health risks of heavy metals in the surrounding soil of stone coal mines, 82 topsoil samples were collected in the study area, and the contents of 8 heavy metals including Cd, Hg, As, Cr, Pb, Cu, Ni, and Zn were determined. The spatial distribution of heavy metals was analyzed using ArcGIS, and the pollution sources of heavy metals were identified using Positive matrix factorization (PMF). Then, Monte Carlo and health risk assessment models were used to evaluate the health risks of different populations. The results showed that the average content of heavy metals followed the order of Zn > Cr > Pb > Cu > Ni > As > Cd > Hg, and the contents of all heavy metals were higher than the soil background values of Hunan Province. The high-value areas of heavy metals content were mostly concentrated in the central region close to areas with a notable concentration of stone coal mines. PMF identified four pollution sources, namely, mining activities (26.9%), atmospheric deposition (18.8%), natural sources (32.8%) and agricultural sources (21.5%). The carcinogenic and non-carcinogenic risks for children were higher than those for adults, with As and Cd posing higher carcinogenic risks to children. Based on the source of health risks, it was determined that the health risks could be primarily attributed to agricultural sources, and As was the main heavy metal causing health risks. This study provides theoretical support for treating heavy metal pollution in mining basins.

Assessing the carcinogenic and non-carcinogenic health risks of metals in the drinking water of Isfahan, Iran

Metals are significant contributors to water pollution, posing serious threats to human health. This study aims to assess the carcinogenic and non-carcinogenic health risks associated with metals in Isfahan drinking water. Eighty water samples were randomly collected from the city's distribution network between January and March 2020-2021. Inductively coupled plasma Optical Emission Spectrometry was used to measure toxic metals, namely Pb, Cr, Cd, Ni, and As concentrations. Results revealed that the mean concentration of Ni (70.03 µg/L) exceeded the WHO reference value (70 µg/L), while the other metals were below the standard values. The average chronic daily intake order of toxic metals was Ni > Cr > Pb > As > Cd. Non-carcinogenic risk assessment through hazard quotient (HQ) and hazard index (HI) demonstrated that both THI for adults (HQingestion + HQdermal = 4.02E-03) and THI for children (HIingestion + HIdermal = 3.83E-03) were below the acceptable limit (less than 1). This indicated no non-carcinogenic risk to residents through water ingestion or dermal exposure. However, findings indicated that the ingestion route was the primary exposure pathway, with HQ values for ingestion exceeding HQ values for dermal adsorption. Carcinogenic risk assessment showed that the risk associated with As metal exceeded the acceptable limit (1 × 10-6). Therefore, implementing treatment improvement programs and appropriate control measures is essential to safeguard the health of Isfahan City residents.

Distribution characteristics, source identification and health risk assessment of trace metals in the coastal groundwater of Taizhou City, China

This study was carried out to evaluate and analyze the fluctuations in groundwater for certain trace metals (Fe, Mn, Cu, Zn, Al, Cd, Cr, Pb, As, and Se) in Taizhou City over three years (2020-2022), evaluate the potential human health risks due to the consumption of groundwater. To quantify the spatiotemporal changes in groundwater trace metals, the heavy metal pollution index (HPI) and heavy metal evaluation index (HEI) were utilized. Furthermore, multivariate statistical methods were utilized to distinguish the sources of trace elements. Deterministic health risk assessment and Monte Carlo health risk simulation methods were employed to evaluate human health risks associated with exposure to trace metals. The results indicate that areas with higher pollution are in the south-central region, with low HPI increasing from 50% to 75% and low HEI from 68.75% to 81.25%, reflecting improved water quality. Correlation matrix analysis and principal component analysis (PCA) pinpointed anthropogenic sources as major trace metal contributors. Cr and As concentrations were associated with farming activities, Cd and Pb concentrations showed links to local industries such as e-waste recycling and shipbuilding. Furthermore, Cu levels in groundwater was influenced by the combined effects of industry, agriculture, and urban sewage discharge. Based on the hazard quotient (HQ) and hazard index (HI) calculations, the majority of groundwater samples did not exceed the reference values, indicating acceptable noncarcinogenic risks for both adults and children. However, the analysis of carcinogenic risk (CR) and uncertainty revealed an overall decreasing trend in carcinogenic risk, with Cr and Cd possessing the highest potential for causing carcinogenic risks. The sensitivities were 46.3%, 53.3%, and 70.3% for Cr, and 18.8%, 27.6%, and 9.3% for Cd.

Prioritization of control factors for heavy metals in groundwater based on a source-oriented health risk assessment model

Heavy metals (HMs) in groundwater seriously threaten ecological safety and human health. To facilitate the effective management of groundwater contamination, priority control factors of HMs in groundwater need to be categorized. A total of 86 groundwater samples were collected from the Huangpi district of Wuhan city, China, during the dry and wet seasons. To determine priority control factors, a source-oriented health risk assessment model was applied to compare the pollution sources and health risks of seven HMs (Cu, Pb, Zn, Cr, Ni, As, and Fe). The results showed that the groundwater had higher As and Fe contents. The sources of HM pollution during the wet period were mainly industrial and agricultural activities and natural sources. During the dry period, origins were more complex due to the addition of domestic discharges, such as sewage wastewater. Industrial activities (74.10% during the wet period), agricultural activities (53.84% during the dry period), and As were identified as the priority control factors for groundwater HMs. The results provide valuable insights for policymakers to coordinate targeted management of HM pollution in groundwater and reduce the cost of HM pollution mitigation.

New insights into health risk assessment on soil trace metal(loid)s: Model improvement and parameter optimization

Trace metal(loid)s (TMs) in soils may pose potential health risks to humans. Due to model uncertainty and variability of exposure parameters, the traditional health risk assessment (HRA) model may lead to inaccurate risk assessment results. Therefore, this study developed an improved HRA model to assess health risks by combining two-dimensional Monte Carlo simulation (2-D MCS) with a Logistic Chaotic sequence based on published data from 2000 to 2021. The results showed children and adult females were the high-risks populations for Non-carcinogenic risk and Carcinogenic risk, respectively. Meanwhile, children's Ingestion rate (IngR < 160.233 mg/day) and adult females' Skin adherence factor (0.026 mg/(cm2•d) < AF < 0.263 mg/(cm2•d)) were used as recommended exposure to make the health risk within acceptable range. Additionally, when performing risk assessment using actual exposure parameters, priority control TMs were identified, with As being the priority control TM for Southwest China and Inner Mongolia, whereas Cr and Pb for Tibet and Yunnan, respectively. Compared to health risk assessment, improved models increased risk assessment accuracy and provided recommended exposure parameter for high-risk populations. This study will provide new insights for soil-related health risk assessment.

Potential ecological risk assessment of heavy metals associated with abattoir liquid waste: A narrative and systematic review

The article presents a narrative and systematic review of the potential ecological risk assessment of heavy metals associated with abattoir liquid waste for knowledge advancement. The narrative review primarily focused on (i) An overview of abattoir operations; (ii) Characteristics of abattoir liquid waste; (iii) Heavy metals in the liquid waste and their health effects; (iv) Environmental impacts of abattoir liquid waste; and (v) Potential ecological risk index (RI) methodology. These provided essential literature for the systematic review. Using exclusive/inclusive criteria, 15 abattoirs that satisfied the eligibility criteria, all located in Nigeria, were used for the systematic review with meta-analysis/meta-regression. Comparative multiple linear meta-regression analyses were used to quantify the heterogeneity variances between the abattoirs based on standardized RIs (SRIs; effect sizes) using eight tau (τ ) estimators in R metafor. The effects of three standardized moderators─ number of metals, metal concentrations, and relative distances between the abattoirs and a pristine environment, Gashaka-Gumti National Park (GNP), were also analyzed. The Sidik-Jonkman (SJ) estimator yielded a realistic output, and the current research findings were based on this estimator. The Cochran statistic (QE) suggested an absence of heterogeneity(p>0.99). Between-study heterogeneities, quantified by H2 (1.05), I2 (4.76%), and τ 2 (0.0032 ± 0.0032 (SE)) statistics were very low, practically suggesting complete homogeneity. The moderators accounted for R * 2 of 95.73% of the total explanatory capacity of the model. The beta coefficients of the moderators and intercept were significant (p-values: 0.009-0.0004). While the first two moderators showed in-phase relations with the SRIs, the third indicated an out-of-phase relation. Such links suggest the existence of abattoir-environment interactive processes. Although the abattoirs are spatially distinct and independent, their operations showed evidence-based homogeneity and posed high ecological risks. Hence, environmental legislation should be strictly enforced while ensuring human settlements are sited reasonably from abattoirs.

Spatial distribution and ecological risk assessment of soil heavy metals in a typical volcanic area: Influence of parent materials

To understand the distribution characteristics and potential ecological risks of heavy metals in soils in the typical volcanic area, 2,592 soil samples were collected from the surface layer (0-20 cm) and 269 samples were collected from the middle (80-100 cm) and deep layers (180-200 cm) in northeast of Hainan province, China. Accordingly, eight heavy metals (Cu, Pb, Zn, Cr, Ni, Cd, As, and Hg) were analyzed and determined. The effects of different parent materials and land use types on the accumulation of heavy metals in soils were compared, and the primary heavy metal sources were analyzed. The pollution level and ecological risk of heavy metals in soils in the study area were evaluated using the geo-accumulation index (Igeo) and potential ecological risk indices (E _i & RI). The results showed that, except that of Pb, the median concentrations of the analyzed heavy metals in the surface soils were higher than the background concentrations in the Hainan Island soils, indicating varying degrees of accumulation. The influence of land use type on the accumulation of heavy metals in surface soils varied from that of the parent materials. Anthropogenic activities highly influenced As, Cd, Hg, and Pb concentrations, whereas geological conditions primarily influenced Cr, Cu, Ni, and Zn concentrations. The Igeo results showed that the mean value of the eight metal elements were greater than zero, except for Pb. In the surface soils, the Igeo values of As, Cd, Hg, and Zn mostly fell into the light to moderate pollution class, and those of Cr, Cu, and Ni fell into the medium and heavy pollution class. The RI of the study area showed a high to significantly high ecological risk because of the Cd, Hg, and Ni concentrations. The results give a new insight in the parent material's geochemical control on the heavy metal elements in soils, and it can serve as a reference for the background value of local soil heavy metals and provide a scientific basis for controlling the potential ecological risk of heavy metals and reasonable land use plans.