Carcinogenic and non-carcinogenic health hazards of potentially toxic elements in commonly consumed rice cultivars in Dhaka city, Bangladesh.

The study aimed to assess the level of potentially toxic elements (As, Cd, Pb, Zn, Cu, Cr, Mn, and Ni) and associated health implications through commonly consumed rice cultivars of Bangladesh available in Capital city, Dhaka. The range of As, Cd, Pb, Zn, Cu, Cr, Mn, and Ni in rice grains were 0.04-0.35, 0.01-0.15, 0.01-1.18, 10.74-34.35, 1.98-13.42, 0.18-1.43, 2.51-22.08, and 0.21-5.96 mg/kg fresh weight (FW), respectively. The principal component analysis (PCA) identified substantial anthropogenic activities to be responsible for these elements in rice grains. The estimated daily intake (EDI) of the elements was below the maximum tolerable daily intake (MTDI) level. The hazard index (HI) was above the threshold level, stating non-carcinogenic health hazards from consuming these rice cultivars. The mean target cancer risk (TCR) of As and Pb exceeded the USEPA acceptable level (10-6), revealing carcinogenic health risks from the rice grains.

Comparison of bladder carcinogenesis biomarkers in the urine of traditional cigarette users and e-cigarette users.

Background: During the use of electronic cigarettes (e-cigarettes), users are still exposed to carcinogens similar to those found in tobacco products. Since these carcinogens are metabolized and excreted in urine, they may have carcinogenic effects on the bladder urinary tract epithelium. This meta-analysis aimed to compare bladder cancer carcinogens in the urine of tobacco users and e-cigarette users using a large number of samples. Methods: A systematic meta-analysis was performed using data obtained from several scientific databases (up to November 2023). This cumulative analysis was performed following the Preferred Reporting Items for Systematic Evaluation and Meta-Analysis (PRISMA) and Assessing the Methodological Quality of Systematic Evaluations (AMSTAR) guidelines, according to a protocol registered with PROSPERO. This study was registered on PROSPERO and obtained the unique number: CRD42023455600. Results: The analysis included 10 high-quality studies that considered polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs) and tobacco-specific nitrosamines (TSNAs). Statistical indicators show that there is a difference between the tobacco user group and the e-cigarette user group in terms of 1-Hydroxynaphthalene (1-NAP) [weighted mean difference (WMD)10.14, 95% confidence interval (CI) (8.41 to 11.88), p < 0.05], 1-Hydroxyphenanthrene (1-PHE) [WMD 0.08, 95% CI (-0.14 to 0.31), p > 0.05], 1-Hydroxypyrene (1-PYR) [WMD 0.16, 95% CI (0.12 to 0.20), p < 0.05], 2-Hydroxyfluorene (2-FLU) [WMD 0.69, 95% CI (0.58 to 0.80), p < 0.05], 2-Hydroxynaphthalene (2-NAP) [WMD 7.48, 95% CI (4.15 to 10.80), p < 0.05], 3-Hydroxyfluorene (3-FLU) [WMD 0.57, 95% CI (0.48 to 0.66), p < 0.05], 2-Carbamoylethylmercapturic acid (AAMA) [WMD 66.47, 95% CI (27.49 to 105.46), p < 0.05], 4-Hydroxy-2-buten-1-yl-mercapturic acid (MHBMA) [WMD 287.79, 95% CI (-54.47 to 630.04), p > 0.05], 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNAL) [WMD 189.37, 95% CI (78.45 to 300.29), p < 0.05], or N0-nitrosonornicotine (NNN) [WMD 11.66, 95% CI (7.32 to 16.00), p < 0.05]. Conclusion: Urinary bladder cancer markers were significantly higher in traditional tobacco users than in e-cigarette users.Systematic review registration: PROSPERO (CRD42023455600: https://www.crd.york.ac.uk/PROSPERO/).

Occupational exposure, carcinogenic and non-carcinogenic risk assessment of formaldehyde in the pathology labs of hospitals in Iran.

Formaldehyde, a known carcinogenic compound, is commonly used in various medical settings. The objective of this study was to assess the carcinogenic and non-carcinogenic risks associated with occupational exposure to formaldehyde. This study was conducted in the pathology labs of four hospitals in Tehran. Cancer and non-cancer risks were evaluated using the quantitative risk assessment method proposed by the United States environmental protection agency (USEPA), along with its provided database known as the integrated risk information system (IRIS). Respiratory symptoms were assessed using the American thoracic society (ATS) questionnaire. The results indicated that 91.23% of exposure levels in occupational groups exceed the NIOSH standard of 0.016 ppm. Regarding carcinogenic risk, 41.03% of all the studied subjects were in the definite carcinogenic risk range (LCR > 10-4), 23.08% were in the possible carcinogenic risk range (10-5 < LCR < 10-4), and 35.90% were in the negligible risk range (LCR < 10-6). The highest index of occupational carcinogenesis was observed in the group of lab technicians with a risk number of 3.7 × 10-4, followed by pathologists with a risk number of 1.7 × 10-4. Furthermore, 23.08% of the studied subjects were within the permitted health risk range (HQ < 1.0), while 76.92% were within the unhealthy risk range (HQ > 1.0). Overall, the findings revealed significantly higher carcinogenic and non-carcinogenic risks among lab technicians and pathologists. Therefore, it is imperative to implement control measures across various hospital departments to mitigate occupational formaldehyde exposure levels proactively. These findings can be valuable for policymakers in the health sector, aiding in the elimination or reduction of airborne formaldehyde exposure in work environments.

Carcinogenic and non-carcinogenic health risks associated with the consumption of fishes contaminated with heavy metals from Manzala Lake, Egypt.

Manzala Lake was sampled to assess the concentrations and possible ecological risks of heavy metals. The mean heavy metal levels in the muscles of Nile tilapia, Flathead grey mullets and African catfish were 0.01, 0.15 and 0.29 mg/kg, respectively, for mercury; 3.16, 4.25 and 4.74 mg/kg for arsenic; 1.01, 0.87 and 0.95 mg/kg for lead; and 0.05, 0.12 and 0.06 mg/kg for cadmium. The levels of heavy metals exceeded their maximum permissible limits in most samples. The EDIs of some metals were higher than their PTDIs or BMDLs. The THQs and TTHQs from metal intake were >1 for Hg and Cd. In addition, the TCR values of As in all fish species were higher than 1.0 × 10-4 indicating a potential health risks from consumption of fish species which need strict hygienic procedures to prevent fish contamination with heavy metals and ensure that their levels did not exceed the maximum permissible limits.

Assessment of carcinogenic and non-carcinogenic risk of exposure to potentially toxic elements in tea infusions: Determination by ICP-OES and multivariate statistical data analysis.

BACKGROUND: The perennial evergreen tea (Camellia sinensis) plant is one of the most popular nonalcoholic drinks in the world. Fertilizers and industrial, agricultural, and municipal activities are the usual drivers of soil contamination, contaminating tea plants with potentially toxic elements (PTEs). These elements might potentially accumulate to larger amounts in the leaves of plants after being taken up from the soil. Thus, frequent monitoring of these elements is critically important. METHODS: The present study intended to determine PTEs (Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb) in both tea leaves and infusions using ICP-OES. Various multivariate data analysis methods such as principal component analysis (PCA) and hierarchical cluster analysis (HCA) were employed to elucidate the potential sources of PTEs contamination, whether from anthropogenic activities or natural origins. Additionally, Pearson's correlation coefficient (PCC) was calculated to assess the relationships between the variables under study. RESULTS: The mean contents (mg/L) of all studied elements in tea infusions decreased in order Mn (150.59 ±â€¯1.66) > Fe (11.39 ±â€¯0.99) > Zn (6.62 ±â€¯0.89) > Cu (5.86 ±â€¯0.62) > Co (3.25 ±â€¯0.64) > Ni (1.69 ±â€¯0.23) > Pb (1.08 ±â€¯0.16) > Cr (0.57 ±â€¯0.09) > Cd (0.46 ±â€¯0.09) > Al (0.05 ±â€¯0.008), indicating that Mn exhibits the highest abundance. The mean concentration trend in tea leaf samples mirrored that of infusions, albeit with higher concentrations of PTEs in the former. The tolerable dietary intake (TDI) value for Ni and provisional tolerable monthly intake (PTMI) value for Cd surpassed the standards set by the WHO and EFSA. Calculated hazard index (HI < 1) and cumulative cancer risk (CCR) values suggest negligible exposure risk. CONCLUSION: Elevated levels of PTEs in commonly consumed tea products concern the public and regulatory agencies.

The immunomodulatory impact of naturally derived neem leaf glycoprotein on the initiation progression model of 4NQO induced murine oral carcinogenesis: a preclinical study.

Introduction: Murine tumor growth restriction by neem leaf glycoprotein (NLGP) was established in various transplanted models of murine sarcoma, melanoma and carcinoma. However, the role of NLGP in the sequential carcinogenic steps has not been explored. Thus, tongue carcinogenesis in Swiss mice was induced by 4-nitroquinoline-1-oxide (4NQO), which has close resemblance to human carcinogenesis process. Interventional role of NLGP in initiation-promotion protocol established during 4NQO mediated tongue carcinogenesis in relation to systemic immune alteration and epithelial-mesenchymal transition (EMT) is investigated. Methods: 4NQO was painted on tongue of Swiss mice every third day at a dose of 25µl of 5mg/ml stock solution. After five consecutive treatment with 4NQO (starting Day7), one group of mice was treated with NLGP (s.c., 25µg/mice/week), keeping a group as PBS control. Mice were sacrificed in different time-intervals to harvest tongues and studied using histology, immunohistochemistry, flow-cytometry and RT-PCR on different immune cells and EMT markers (e-cadherin, vimentin) to elucidate their phenotypic and secretory status. Results: Local administration of 4NQO for consecutive 300 days promotes significant alteration in tongue mucosa including erosion in papillae and migration of malignant epithelial cells to the underlying connective tissue stroma with the formation of cell nests (exophytic-hyperkeratosis with mild dysplasia). Therapeutic NLGP treatment delayed pre-neoplastic changes promoting normalization of mucosa by maintaining normal structure. Flow-cytometric evidences suggest that NLGP treatment upregulated CD8+, IFNγ+, granzyme B+, CD11c+ cells in comparison to 4NQO treated mice with a decrease in Ki67+ and CD4+FoxP3+ cells in NLGP treated cohort. RT-PCR demonstrated a marked reduction of MMP9, IL-6, IL-2, CD31 and an upregulation in CCR5 in tongues from 4NQO+NLGP treated mice in comparison to 4NQO treated group. Moreover, 4NQO mediated changes were associated with reduction of e-cadherin and simultaneous up-regulation of vimentin expression in epithelium that was partially reversed by NLGP. Discussion: Efficacy of NLGP was tested first time in sequential carcinogenesis model and proved effective in delaying the initial progression. NLGP normalizes type 1 immunity including activation of the CD8+T effector functions, reduction of regulatory T cell functions, along with changes in EMT to make the host systemically alert to combat the carcinogenic threat.

[Characterization of Metal Elements in Atmospheric PM2.5 and Health Risk Assessment in Heze in Winter from 2017 to 2018].

Atmospheric PM2.5 samples were collected in Heze, Shandong Province, from a total of three sampling sites at Heze College, Huarun Pharmacy, and a wastewater treatment plant between October 15, 2017 and January 31, 2018, to determine the concentrations of 21 metal elements in PM2.5 using inductively coupled plasma mass spectrometry (ICP-MS). The degree of elemental enrichment was also discussed, the health risks and potential heavy metal ecological risks were assessed. The results showed that ρ (PM2.5) ranged from 26.7 to 284.1 µg·m-3 at the three sampling sites during the sampling period, and the concentration values did not differ significantly, all of which were at high pollution levels. The highest concentrations of K were found in the three sampling sites, accounting for 31.03%, 39.47%, and 38.43% of the total, respectively, mainly due to the high contribution of biomass burning in autumn and winter in Heze, a large agricultural city. The highest concentrations of Zn, 89.70, 84.21, and 67.68 ng·m-3, were found in the trace elements at the three sampling sites, respectively. The enrichment factor results showed that the enrichment factor values of Zn, Pb, Sn, Sb, Cd, and Se were higher than 100, among which the enrichment factors of Cd and Se were higher than 2 000 and 4 000, respectively, which were significantly influenced by anthropogenic activities and might have been related to industrial production, metal smelting, road sources, and coal combustion emissions. The health risk results showed that there was some potential non-carcinogenic risk (HQ>0.1 for children and adults) for As and a combined potential non-carcinogenic risk (HI>0.1) and some potential carcinogenic risk (CRT>1×10-6) for both children and adults at the three sampling sites. There was a more significant carcinogenic risk (CRT>1×10-4) for adults at the wastewater treatment plant, and the slightly higher carcinogenic risk for adults than that for children may have been related to the longer outdoor activity and higher PM2.5 exposure for adults. The elements with the highest potential ecological risk values were Cd, As, and Pb, with Cd exhibiting a very high potential ecological risk that should be taken seriously. All three sampling sites showed a very high combined potential ecological risk, with the intensity spatially expressed as Heze College>Huarun Pharmacy>wastewater treatment plant.

[Health Risk Assessment for an Arsenic-contaminated Site Based on Monte Carlo Simulation and Parameters Optimization].

Risk assessment is a critical part of risk management for contaminated sites. However， in the specific management practice of As-contaminated sites， it is difficult to obtain realistic health risks for contaminated sites based on the total amount of pollutants and determined values of the model， thus preventing the control requirements of later remediation to be met. An increasing number of studies have recently been conducting risk assessments by considering bioavailability， modification parameters， and combined probabilistic models. To improve the accuracy of risk assessment results， taking a large As-contaminated site as a case， 432 sampling sites were set up and collected at different depths to analyze the level and distribution characteristics of As pollution， and probabilistic risk assessment was conducted with the modification of model parameters through literature research and Monte Carlo simulation. Then， the impact of traditional methods and probabilistic methods on health risk assessment was explored in comparison. The results indicated that ω（As） in the top soil of the study area ranged from 2.70-97.0 mg·kg-1， with a spatial variation coefficient of 0.61 and weaker spatial continuity. The carcinogenic risk and hazard index obtained by the traditional risk assessment method were 2.12E-4 and 8.36， respectively， which obviously overestimated the actual risk level and were not conductive to the refined management of As-contaminated sites. Combined with modification of model parameters and probabilistic risk assessment， the non-carcinogenic risk for adults and children was found to be at an acceptable level， and the carcinogenic risk was reduced by nearly an order of magnitude compared to that in the conventional method. Considering the relative biological effectiveness （RBA） of As， the 95% quantile of the total carcinogenic risk was 1.24E-5， a reduction of up to 36.41% compared to the uncorrected corresponding risk value of 1.95E-5. The carcinogenic risk of soil As for adults and children in the study area exceeded acceptable risk levels 1E-6， with oral ingestion of soil being the primary route of exposure. In addition， the results of the sensitivity analysis of the parameters showed that As concentration， daily oral ingestion rate of soils， and exposure duration of children had relatively larger effects for health risks. This work will provide a methodological and theoretical basis for achieving accurate risk assessment of As-contaminated sites and provide concepts for refined risk management.

Multivariate analysis of carcinogenic equivalence (CEQ) to characterize carcinogenic VOC emissions in a typical petrochemical industrial park in Taiwan.

Large industrial emissions of volatile organic compounds (VOCs) from the petrochemical industry are a critical concern due to their potential carcinogenicity. VOC emissions vary in composition depending on the source and occur in mixtures containing compounds with varying degrees of toxicity. We proposed the use of carcinogenic equivalence (CEQ) and multivariate analysis to identify the major contributors to the carcinogenicity of VOC emissions. This method weights the carcinogenicity of each VOC by using a ratio of its cancer slope factor to that of benzene, providing a carcinogenic equivalence factor (CEF) for each VOC. We strategically selected a petrochemical industrial park in southern Taiwan that embodies the industry's comprehensive nature and serves as a representative example. The CEQs of different emission sources in three years were analyzed and assessed using principal component analysis (PCA) to characterize the major contributing sectors, vendors, sources, and species for the carcinogenicity of VOC emissions. Results showed that while the study site exhibited a 20.7 % (259.8 t) decrease in total VOC emissions in three years, the total CEQ emission only decreased by 4.5 % (15.9 t), highlighting a potential shift in the emitted VOC composition towards more carcinogenic compounds. By calculating CEQ followed by PCA, the important carcinogenic VOC emission sources and key compounds were identified. More importantly, the study compared three approaches: CEQ followed by PCA, PCA followed by CEQ, and PCA only. While the latter two methods prioritized sources based on emission quantities, potentially overlooking less abundant but highly carcinogenic compounds, the CEQ-first approach effectively identified vendors and sources with the most concerning cancer risks. This distinction underscores the importance of selecting the appropriate analysis method based on the desired focus. Our study highlighted how prioritizing CEQ within the analysis framework empowered the development of precise control measures that address the most carcinogenic VOC sources.

Integrated application of multiple indicators and geographic information system-based approaches for comprehensive assessment of environmental impacts of toxic metals-contaminated agricultural soils and vegetables.

Conventional monitoring and mapping approaches are laborious, expensive, and time-consuming because they need a large number of data and consequently extensive sampling and experimental operations. Therefore, due to the growing concern about the potential of contamination of soils and agricultural products with heavy metals (HMs), a field experiment was conducted on 77 farm lands in an area of 2300 ha in the southeast of Shiraz (Iran) to investigate the source of metal contamination in the soils and vegetables and to model spatial distribution of HMs (iron, Fe; manganese, Mn; copper, Cu; zinc, Zn; cadmium, Cd; nickel, Ni, and lead, Pb) over the region using geographic information system (GIS) and geostatistical (Ordinary Kriging, OK) approaches and compare the results with deterministic approaches (Inverse Distance Weighting, IDW with different weighting power). Furthermore, some ecological and health risks indices including Pollution index (PI), Nemerow integrated pollution index (NIPI), pollution load index (PLI), degree of contamination (Cdeg), modified contamination degree (mCd), PIaverage and PIvector for soil quality, multi-element contamination (MEC), the probability of toxicity (MERMQ), the potential ecological index (RI), total hazard index (THI) and total carcinogenic risk index (TCR) based on ingestion, inhalation, and dermal exposure pathways for adults and children respectively for analyzing the noncarcinogenic and carcinogenic risks were calculated. Experimental semivariogram of the mentioned HMs were calculated and theoretical models (i.e., exponential, spherical, Gaussian, and linear models) were fitted in order to model their spatial structures and to investigate the most representative models. Moreover, principal component analysis (PCA) and cluster analysis (CA) were used to identify sources of HMs in the soils. Results showed that IDW method was more efficient than the OK approach to estimate the properties and HMs contents in the soils and plants. The estimated daily intake of metals (DIM) values of Pb and Ni exceeded their safe limits. In addition, Cd was the main element responsible for ecological risk. The PIave and PIvector indices showed that soil quality in the study area is not suitable. According to mCd values, the soils classified as ultra-high contaminated for Cu and Cd, extremely high for Zn and Pb, very high, high, and very low degree of contamination for Ni, Mn, and Fe, respectively. 36, 60, and 4 % of the sampling sites had high, medium, and low risk levels with 49, 21, and 9 % probability of toxicity, respectively. The maximum health risk index (HRI) value of 20.42 with extremely high risk for children was obtained for Ni and the HI for adults and children were 0.22 and 1.55, respectively. The THI values of Pb and Cd were the highest compared to the other HMs studied, revealing a possible non-cancer risk in children associated with exposure to these metals. The routes of exposure with the greatest influence on the THI and TCR indices were in the order of ingestion > inhalation > dermal. Therefore, ingestion, as the main route of exposure, is the route of greatest contribution to health risks. PCA analysis revealed that Fe, Mn, Cu, and Ni may originate from natural sources, while Fe was appeared to be controlled by fertilizer, and Cu primarily coming from pesticide, while Cd and Pb were mainly associated with the anthropogenic contamination, atmospheric depositions, and terrific in the urban soils. While, Zn mainly originated from fertilization. Findings are vital for developing remediation approaches for controlling the contaminants distribution as well as for monitoring and mapping the quality and health of soil resources.

Human health risk assessment of metal-contaminated soils in Sydney estuary catchment (Australia).

Sydney estuary catchment supports the largest city in Australia and provides essential eco-social and environmental services; however, the region has been influenced by extensive anthropogenic modification. Soil metal concentrations in the catchment had been studied previously; however, the current investigation was designed to determine the risk posed by these contaminants to human health. Soil metal concentrations were higher than observed in most global capitals and increased substantially in the south and south-east of the catchment and close to the central business district. Road-side soils and road dust contained the highest concentration of metals in the catchment. Lead in catchment soils was closely related to traffic density and sourced from the historic use of Pb in petrol. A human health assessment indicated that soil Cd, Ni and Zn posed no non-carcinogenic risk (NCR), or carcinogenic risk (CR) for children, or adults in Sydney estuary catchment and that Cu and Cr may pose minor NCR for children. Vehicle-related Pb raised the greatest human health risk in catchment soils and may pose NCR at 32% and 4.3% of sites for children and adults, respectively. Inconsistent analytical techniques used in CR and NCR evaluations produce incomparable assessments and a consistent` methodology is suggested to improve interpretation. Human health risk may well be higher than commonly calculated due to pollutants present in urban soil not being included in assessments.

Analysing N-nitrosamine occurrence and sources in karst reservoirs, Southwest China.

N-nitrosamines in reservoir water have drawn significant attention because of their carcinogenic properties. Karst reservoirs containing dissolved organic matter (DOM) are important drinking water sources and are susceptible to contamination because of the fast flow of various contaminants. However, it remains unclear whether N-nitrosamines and their precursor, DOM, spread in karst reservoirs. Therefore, this study quantitatively investigated the occurrence and sources of N-nitrosamines based on DOM properties in three typical karst reservoirs and their corresponding tap water. The results showed that N-nitrosamines were widely spread, with detection frequencies > 85%. Similar dominant compounds, including N-nitrosodimethylamine, N-nitrosomethylethylamine, N-nitrosopyrrolidine, and N-nitrosodibutylamine, were observed in reservoirs and tap water, with average concentrations of 4.7-8.9 and 2.8-6.7 ng/L, respectively. The average carcinogenic risks caused by these N-nitrosamines were higher than the risk level of 10-6. Three-dimensional fluorescence excitation-emission matrix modeling revealed that DOM was composed of humus-like component 1 (C1) and protein-like component 2 (C2). Fluorescence indicators showed that DOM in reservoir water was mainly affected by exogenous pollution and algal growth, whereas in tap water, DOM was mainly affected by microbial growth with strong autopoietic properties. In the reservoir water, N-nitrosodiethylamine and N-nitrosopiperidine were significantly correlated with C2 and biological indicators, indicating their endogenously generated sources. Based on the principal component analysis and multiple linear regression methods, five sources of N-nitrosamines were identified: agricultural pollution, microbial sources, humus sources, degradation processes, and other factors, accounting for 46.8%, 36.1%, 7.82%, 8.26%, and 0.96%, respectively. For tap water, two sources, biological reaction processes, and water distribution systems, were identified, accounting for 75.7% and 24.3%, respectively. Overall, this study presents quantitative information on N-nitrosamines' sources based on DOM properties in typical karst reservoirs and tap water, providing a basis for the safety of drinking water for consumers.

Health risk and pollution associated with trace metals in the waters of the Ebolowa municipal lake basin (Central Africa): evidence from hydrochemistry, quality indices, and statistical analyses.

The aim of this study was to investigate the status of trace metals (As, Cr, Cu, Ni, Pb, Fe, and Zn) and health and carcinogenic risk associated then in the Ebolowa Municipal Lake (EML) basin. To this end, 21 water samples were collected from the EML and its two tributaries, Mfoumou and Bengo'o, and analyzed by Quantofix method (nanocolors and visiocolor ECO) by using the MACHEREY-NAGEL photometer. The data were processed using multivariate statistics. The results showed that all the physicochemical parameters (pH, EC, and TDS), with the exception of TDS, comply with were within WHO limits. The distribution of trace metals at the three sites investigated was as follows: Zn (80-400 ± 1.58 µg/L) > Cu (50-150 ± 9.38 µg/L) > Fe (10-40 ± 0.71 µg/L) > Pb (1-20 ± 3.02 µg/L) > As (1-9 ± 0.44 µg/L) > Ni (1-9 ± 1.48 µg/L). However, the highest values were observed in the EML and the Mfoumou River, where Pb pollution was noted. Statistical analysis showed that anthropogenic inputs increase the presence of Cr, Cu, Pb, and Zn. Trace Metal Pollution Index values were below 15 at all sites, illustrating low levels of pollution. The trace metal evaluation index values for the Bengo'o stream are pure (mean = 0.6), slightly affected in the Mfoumou stream (mean = 2.0), and moderately affected in the EML (mean = 2.2). The toxicity load index values illustrate that the waters studied are toxic. The non-carcinogenic (HI) and carcinogenic (CR) health risk index values suggest a risk linked to oral ingestion in the LME and Mfoumou watercourses. The latter appears to be the main source of allochthonous pollutant input to the EML.

Control of tobacco-specific nitrosamines by the Bacillus siamensis: Strain isolation, genome sequencing, mechanism analysis and genetic engineering.

Nitrosamines are considered carcinogens that threaten human health and environment. Especially, high contents of Tobacco-specific nitrosamines (TSNAs) are generated during the fermentation process of cigar tobacco. To control the accumulation of TSNAs, one novel strain WD-32 was isolated by comprehensively evaluating the reduction characteristics of nitrate, nitrite, and TSNAs, and this strain was identified as Bacillus siamensis by 16 S rRNA gene analysis and MALDI-TOF MS evaluation. Subsequently, whole genome sequencing of B. siamensis WD-32 was carried out to excavate important genes and enzymes involved, and the possible reduction mechanism of TSNAs was explored. More importantly, the reduction of TSNAs by B. siamensis was significantly promoted by knockout of narG gene. During the practical agricultural fermentation process of the cigar tobacco leaves, the treatment by the WD-32∆narG cells resulted in a 60% reduction of the total TSNAs content compared with the control, and the concentrations of the NNN and NNK were decreased by 69% and 59%, respectively. In summary, this study offers efficient strains for reduction of the TSNAs in cigar tobacco, and provides new insights into the reduction mechanism of TSNAs, which will promote the application of microbial methods in control of TSNAs and nitrite.

Risk assessment and source analysis of heavy metals in soil around an asbestos mine in an arid plateau region, China.

Asbestos is widely used in construction, manufacturing, and other common industrial fields. Human activities such as mining, processing, and transportation can release heavy metals from asbestos into the surrounding soil environment, posing a health hazard to the mining area's environment and its surrounding residents. The purpose of the present study was to determine the extent of ecological and human health damage caused by asbestos pollution, as well as the primary contributors to the contamination, by examining a large asbestos mine and the surrounding soil in China. The level of heavy metal pollution in soil and sources were analyzed using methods such as the geo-accumulation index (Igeo), potential ecological risk index (RI), and positive matrix factorization (PMF) model. A Monte Carlo simulation-based health risk model was employed to assess the health risks of heavy metals in the study area's soil to human beings. The results showed that the concentrations of As, Pb, Cr, Cu, and Ni in the soil were 1.74, 0.13, 13.31, 0.33, and 33.37 times higher than the local soil background values, respectively. The Igeo assessment indicated significant accumulation effects for Ni, Cr, and As. The RI evaluation revealed extremely high comprehensive ecological risks (RI ≥ 444) in the vicinity of the waste residue heap and beneficiation area, with Ni exhibiting strong individual potential ecological risk (Eir ≥ 320). The soil health risk assessment demonstrated that As and Cr posed carcinogenic risks to adults, with mean carcinogenic indices (CR) of 1.56E - 05 and 4.14E - 06, respectively. As, Cr, and Cd posed carcinogenic risks to children, with mean CRs of 1.08E - 04, 1.61E - 05, and 2.68E - 06, respectively. Cr also posed certain non-carcinogenic risks to both adults and children. The PMF model identified asbestos contamination as the primary source of heavy metals in the soil surrounding the asbestos mining area, contributing to 79.0%. According to this study, it is recommended that management exercise oversight and regulation over the concentrations of Ni, Cr, Cd, and As in the soil adjacent to asbestos mines, establish a designated control zone to restrict population activities, and locate residential zones at a safe distance from the asbestos mine production zone.

Dietary exposure to acrylamide among the Malaysian adult population.

This study aimed to estimate the Malaysian adult population's current dietary exposure and margin of exposure (MOE) to the carcinogenic processing contaminant, acrylamide. A total of 448 samples from 11 types of processed foods were collected randomly throughout Malaysia in the year 2015 and 2016. Acrylamide was analysed in samples using Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) with a limit of detection (LOD) of 10 µg/kg and a limit of quantification (LOQ) of 25 µg/kg. The highest average level of acrylamide (772 ± 752 µg/kg) was found in potato crisps, followed by French fries (415 ± 914 µg/kg) and biscuits (245 ± 195 µg/kg). The total acrylamide exposure for the adult Malaysian was 0.229 and 1.77 µg/kg body weight per day for average and high consumers, respectively. The MOE were 741 and 1875 for the average consumer based on cancer and non-cancer effects of acrylamide, respectively. Meanwhile, for high consumers, the MOE is 96 for cancer and 243 for non-cancer effects. These findings indicate potential carcinogenic risks from acrylamide exposure among Malaysian adults, especially in Malay and other Bumiputra groups compared to Chinese, Indian, and other ethnic groups, while non-cancer effects appeared less concerning.

Spatial distribution, environmental behavior, and health risk assessment of PAHs in soils at prototype coking plants in Shanxi, China: Stable carbon isotope and molecular composition analyses.

To investigate the environmental behavior of and carcinogenic risk posed by 16 priority-controlled polycyclic aromatic hydrocarbons (PAHs), soil samples and air samples from the coke oven top were collected in two prototype coking plants (named PF and JD). The PF soils contained more PAHs than the JD soils because the PF plant employed the side-charging technique and had a lower coke oven height. The soils from both plants contained enough PAHs to pose a carcinogenic risk, and this risk was higher in the PF plant. Data were collected on the source characteristic spectrum of stable carbon isotopic composition (δ13C) of PAHs emitted from the coke oven top (δ13C values of -36.02‰ to -32.05‰ for gaseous PAHs and -34.09‰ to -25.28‰ for particulate PAHs), and these data fill a research gap and may be referenced for isotopic-technology-based source apportionment. Diagnostic ratios and isotopic technology revealed that the coking plant soils were mainly influenced by the coking process, followed by vehicle exhaust; the soils near the boundary of each plant were slightly affected by C3 plant burning. For most PAHs [excluding fluoranthene, benzo(k)fluoranthene, indeno(1,2,3-c,d)pyrene, and dibenzo(a,h)anthracene], the dominant migration process was the net volatilization of PAHs from soil to air. In the PF plant, 13C was depleted in gaseous PAHs during volatilization.

A comprehensive investigation of geoenvironmental pollution and health effects from municipal solid waste landfills.

This study investigates human health risks associated with heavy metals (HMs) occurrence in municipal solid waste (MSW) landfills. For testing of selected MSW landfills steps were involved, including site characterization, soil sampling and chemical testing, statistical analysis, as well as health risk assessment, carcinogenic and non-carcinogenic effects. For the Polish landfill (Radiowo) the average HMs concentrations were found in the following order: Zn (52.74 mg/kg DM) > Pb (28.32 mg/kg DM) > Cu (12.14 mg/kg DM) > Ni (4.50 mg/kg DM) > Cd (3.49 mg/kg DM), while for the Czech landfill (Zdounky): Zn (32.05 mg/kg DM) > Cu (14.73 mg/kg DM) > Ni (4.73 mg/kg DM) > Pb (0.10 mg/kg DM) = Cd (0.10 mg/kg DM). Strong positive correlations between selected HMs demonstrated identical origins. Principal component analysis (PCA) performed for the Radiowo landfill transferred the soil parameters into three principal components (PCs), accounting for 87.12% of the total variance. The results of the PCA analysis for the Zdounky landfill revealed three PCs responsible for 95.16% of the total variance. The exposure pathways of HMs for landfills were in the following order: ingestion > dermal absorption > inhalation. For both landfills, the values of hazard quotient were lower than 1, indicating no potential negative health effects. In terms of the hazard index (HI), for both landfills, no adverse human health effects occur (HI < 1). The incremental lifetime cancer risk (ILCR) values indicated negligible or acceptable carcinogenic risk of HMs (average ILCR in the range from 5.01E-10 to 5.19E-06).

Development of occupation-based exposure matrix of lead for Korean workers: challenges and opportunities.

OBJECTIVES: Industry- and occupation-based carcinogen exposure matrices play a pivotal role in preventing occupational cancer. While the Korean CARcinogen EXposure (K-CAREX) has been developed in recent years to assess exposure prevalence and intensity by industry, the feasibility of constructing an occupation-based exposure matrix remains unexplored. Hence, the objective of this study is to explore the potential of combining the nationwide work environment measurement database (WEMD) and the special health examination database (SHED) to develop a comprehensive occupation-based exposure matrix. METHODS: The WEMD provides information on airborne lead measurements, including industry codes, but it does not include data related to occupations. In contrast, the SHED contains information on both occupation and blood lead levels. By integrating these 2 databases, we attempted to assess airborne lead exposure levels by occupation. Additionally, we performed a rank correlation analysis to compare the airborne exposure levels with corresponding blood lead levels according to occupation. RESULTS: A total of 35 425 workers who both wore air samplers for lead and underwent special health examinations for lead were extracted between 2019 and 2021. An occupation-based exposure matrix was developed to evaluate the intensity of lead exposure across a range of occupations, encompassing 51 minor occupations and 70-unit occupations. Rank correlation analyses showed strong positive correlations between airborne lead and blood lead measurements according to occupation. CONCLUSIONS: Our study findings suggest that combining 2 nationwide surveillance databases can be an effective approach for creating an occupation-based exposure matrix. However, our results also highlight several limitations that need to be addressed in future studies to improve the accuracy and reliability of such matrices.

Concentration of heavy metals in pasteurized and sterilized milk and health risk assessment across the globe: A systematic review.

OBJECTIVE: Although milk and dairy products are almost complete food, they can contain toxic heavy elements with potential hazards for consumers. This review aims to provide a comprehensive report on the occurrence, concentration, and health risks of selected heavy metals in pasteurized and sterilized milk recorded worldwide. METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) was used to develop this systematic review. Databases included the Web of Knowledge, Scopus, Scientific Information Database, Google Scholar, and PubMed from inception until January 2023. Keywords related to the terms "Heavy metals", "Arsenic" and "Pasteurized and sterilized milk" and "Risk Assessment" were used. The potential health risks to human health from milk daily consumption were estimated using extracted data on heavy metals concentration based on metal estimated daily intake, target hazard quotient, and carcinogenic risk. RESULTS: A total of 48 potentially relevant articles with data on 981 milk samples were included in the systematic review. Atomic Absorption Spectroscopy, atomic absorption spectroscopy, inductively coupled plasma-mass spectrometry, and inductively coupled plasma-optical emission spectrometry were the most common valid methods to measure heavy metals in milk samples. Following the initial evaluation, Cu, Cd, Zn, and Pb were the most contaminants, which exceeded the maximum permissible criteria in 94%, 67%, 62%, and 46% of the milk samples tested. Relying on target hazard quotient and carcinogenic risk results, milk consumers in 33(68.75%) and 7 (14.5%) studies were exposed to moderate to high levels of carcinogenic and non-carcinogenic risk, respectively. The highest level of risk is due to the consumption of pasteurized and sterilized milk detected in Pakistan, Brazil, Egypt, Slovakia, and Turkey. CONCLUSION: The elevated levels of heavy metals in milk samples, especially Pb and Cd is a public health concern; therefore, maximum control and strict regulations must be adopted to decrease heavy metals contaminants in the dairy industry. Further studies are required to develop safe milk processing and handling methods for the decontamination of heavy metals in milk and its products.