Biomonitoring of humans exposed to arsenic, chromium, nickel, vanadium, and complex mixtures of metals by using the micronucleus test in lymphocytes

Use of micronucleus cytome assays with buccal cells for the detection of genotoxic effects: A systematic review and meta-analysis of occupational exposures to metals

Micronucleus (MN) assays with buccal cells are at present widely used to investigate occupational exposures to genotoxic carcinogens. This article describes their use for the monitoring of metal exposed workers. We found in total 73 relevant articles, in the majority (97 %) increased MN and/or other nuclear anomalies were reported. Most studies were realized in South East Asia and South America. A variety of different occupations was studied including welders, electroplaters, painters, workers in battery recycling and production, tannery workers, dental technicians, miners, workers in foundries and smelters, and also subjects working in waste recycling, glass, aluminum and steel production. In many investigations the effects increased with the duration of the working period. The quality of individual studies was evaluated with a quality score tool. The number of cells was in most studies sufficient and DNA-specific stains were used. However, many studies have shortcomings, e.g. they focused solely on MN formation and did not evaluate anomalies, which provide additional information about the stability of the genetic material and acute cytotoxic effects. Only 35 % of the investigations contain quantitative information about exposures to metals and other toxicants. In 6 of these studies, correlations were observed between the concentrations of specific metals (As, Pb, Cr, Cd) in body fluids and MN frequencies. Taken together, the available data indicate that the MN assay can be used to detect chromosomal damage in metal exposed groups; furthermore, it enables also comparisons between subgroups differing in regard to their exposure and allows an estimation of the efficiency of protective measures. The exposure of workers to metals is currently controlled with chemical analytical measurements only, MN assays with buccal cells could contribute to further improve the safety at workplaces as they reflect the biological consequences including synergistic and antagonistic interactions between toxicants.

HK2 and LDHA upregulation mediate hexavalent chromium-induced carcinogenesis, cancer development and prognosis through miR-218 inhibition

Hexavalent chromium [Cr(VI)] is one of the most common environmental contaminants due to its tremendous industrial applications, but its effects and mechanism remain to be investigated. Our previous studies showed that Cr(VI) exposure caused malignant transformation and tumorigenesis. This study showed that glycolytic proteins HK2 and LDHA levels were statistically significant changed in blood samples of Cr(VI)-exposed workers and in Cr-T cells compared to the control subjects and parental cells. HK2 and LDHA knockdown inhibited cell proliferation and angiogenesis, and higher HK2 and LDHA expression levels are associated with advanced stages and poor prognosis of lung cancer. We found that miR-218 levels were significantly decreased and miR-218 directly targeted HK2 and LDHA for inhibiting their expression. Overexpression of miR-218 inhibited glucose consumption and lactate production in Cr-T cells. Further study found that miR-218 inhibited tumor growth and angiogenesis by decreasing HK2 and LDHA expression in vivo. MiR-218 levels were negatively correlated with HK2 and LDHA expression levels and cancer development in human lung and other cancers. These results demonstrated that miR-218/HK2/LDHA pathway is vital for regulating Cr(VI)-induced carcinogenesis and human cancer development.

A comparative study on chromium-induced micronuclei assessment in the peripheral blood of Hsd:ICR mice

This study investigated the genotoxic effects of chromium (Cr) in Hsd:ICR mice, considering factors such as oxidative state, apoptosis, exposure pathway, duration, pregnancy, and transplacental exposure. Genotoxicity was assessed using the erythrocytes' micronucleus (MN) assay, while apoptosis was evaluated in nucleated blood cells. The results showed that Cr(III) (CrK(SO4 )2 and CrCl3 ) did not induce any marked genotoxic damage. However, Cr(VI) (CrO3 , K2 Cr2 O7 , Na2 Cr2 O7 , and K2 CrO4 ) produced varying degrees of genotoxicity, with CrO3 being the most potent. MN frequencies increased following 24-h exposure, with a greater effect in male mice. Administering 20 mg/kg of CrO3 via gavage did not lead to significant effects compared to intraperitoneal administration. Short-term oral treatment with a daily dose of 8.5 mg/kg for 49 days elevated MN levels only on day 14 after treatment. Pregnant female mice exposed to CrO3 on day 15 of pregnancy exhibited reduced genotoxic effects compared to nonpregnant animals. However, significant increases in MN levels were found in their fetuses starting 48 h after exposure. In summary, data indicate the potential genotoxic effects of Cr, with Cr(VI) forms inducing higher genotoxicity than Cr(III). These findings indicate that gender, exposure route, and pregnancy status might influence genotoxic responses to Cr.

Wastewater Treatment Using Membrane Bioreactor Technologies: Removal of Phenolic Contaminants from Oil and Coal Refineries and Pharmaceutical Industries

Huge amounts of noxious chemicals from coal and petrochemical refineries and pharmaceutical industries are released into water bodies. These chemicals are highly toxic and cause adverse effects on both aquatic and terrestrial life. The removal of hazardous contaminants from industrial effluents is expensive and environmentally driven. The majority of the technologies applied nowadays for the removal of phenols and other contaminants are based on physio-chemical processes such as solvent extraction, chemical precipitation, and adsorption. The removal efficiency of toxic chemicals, especially phenols, is low with these technologies when the concentrations are very low. Furthermore, the major drawbacks of these technologies are the high operation costs and inadequate selectivity. To overcome these limitations, researchers are applying biological and membrane technologies together, which are gaining more attention because of their ease of use, high selectivity, and effectiveness. In the present review, the microbial degradation of phenolics in combination with intensified membrane bioreactors (MBRs) has been discussed. Important factors, including the origin and mode of phenols' biodegradation as well as the characteristics of the membrane bioreactors for the optimal removal of phenolic contaminants from industrial effluents are considered. The modifications of MBRs for the removal of phenols from various wastewater sources have also been addressed in this review article. The economic analysis on the cost and benefits of MBR technology compared with conventional wastewater treatments is discussed extensively.

Update of the risk assessment of inorganic arsenic in food

The European Commission asked EFSA to update its 2009 risk assessment on arsenic in food carrying out a hazard assessment of inorganic arsenic (iAs) and using the revised exposure assessment issued by EFSA in 2021. Epidemiological studies show that the chronic intake of iAs via diet and/or drinking water is associated with increased risk of several adverse outcomes including cancers of the skin, bladder and lung. The CONTAM Panel used the benchmark dose lower confidence limit based on a benchmark response (BMR) of 5% (relative increase of the background incidence after adjustment for confounders, BMDL05) of 0.06 μg iAs/kg bw per day obtained from a study on skin cancer as a Reference Point (RP). Inorganic As is a genotoxic carcinogen with additional epigenetic effects and the CONTAM Panel applied a margin of exposure (MOE) approach for the risk characterisation. In adults, the MOEs are low (range between 2 and 0.4 for mean consumers and between 0.9 and 0.2 at the 95th percentile exposure, respectively) and as such raise a health concern despite the uncertainties.

Pathophysiology of the Toxic Effects in Metallic Implants

Implants play a very crucial role in modern era of medicine and address several needs in all the medical specialties. Both essential and nonessential metals released from implants at high concentrations can impair biological functions and result in toxicity involving multiple systems of the body. Furthermore, the toxicity information is typically based on exposure through dietary intake and/or occupational/environmental exposure but, since the in vivo implant environment and its composition is different or unknown, individual implants toxic effects needs to be elaborated. Several clinical and nonclinical assessment tools are advised by FDA to evaluate biocompatibility issues, such as risk of immunological response, tissue destruction or overgrowth, and other adverse reactions. The Center for Devices and Radiological Health (CDRH) Biocompatibility Guidelines state that biocompatibility end points caused by metallic implants includes cytotoxicity, sensitization, acute and chronic systemic toxicity, pyrogenicity, genotoxicity, carcinogenicity, implantation, hemocompatibility, reproductive abnormalities, developmental toxicity and biodegradation. Exposure to metal ions which acts as haptens can lead to both local and systemic hypersensitivity reactions which are generally believed to be a Type IV (delayed hypersensitivity) response. Currently, most assessment tools of implant associated hypersensitivity are based on skin sensitization which provides further scopes for research in understanding patient specific immune response causing systemic hypersensitivity.

Genotoxic, mutagenic, and cytotoxic analysis in bats in mining area

Pollution generated by the mining industry can cause harm to wildlife. This study aimed to evaluate the cytotoxicity, genotoxicity and mutagenicity in bats environmentally exposed to open pit mining. Thus, 62 bats of the following species, Carollia perspicillata, Glossophaga soricina, Phyllostomus hastatus, and Desmodus rotundus exposed to mining activities (ferronickel) were used in the analysis. The animals were obtained in samplings in July and November of 2021, totaling 8 days of sampling in the field. The results indicated that species differ in the frequency of genotoxic damage between sampling points within the mining landscape. Cytotoxicity was observed by scoring of karyorrhexis, pyknosis and karyolysis. The most captured species, C. perspicillata, showed differences in DNA damage between exposed and unexposed populations, but no differences were observed between males (n = 14) and females (n = 20). G. soricina was also a sensitive species for indicating a high frequency of DNA damages compared to the omnivore P. hastatus. Elements such as Mn, Cr, Pb, and Zn observed in water samples were at high levels in the mining area. We conclude that bats in mining areas are susceptible to increased DNA damage as already identified for other species.

Implementation of effect biomarkers in human biomonitoring studies: A systematic approach synergizing toxicological and epidemiological knowledge

Human biomonitoring (HBM) studies have highlighted widespread daily exposure to environmental chemicals. Some of these are suspected to contribute to adverse health outcomes such as reproductive, neurological, and metabolic disorders, among other developmental and chronic impairments. One of the objectives of the H2020 European Human Biomonitoring Initiative (HBM4EU) was the development of informative effect biomarkers for application in a more systematic and harmonized way in large-scale European HBM studies. The inclusion of effect biomarkers would complement exposure data with mechanistically-based information on early and late adverse effects. For this purpose, a stepwise strategy was developed to identify and implement a panel of validated effect biomarkers in European HBM studies. This work offers an overview of the complete procedure followed, from comprehensive literature search strategies, selection of criteria for effect biomarkers and their classification and prioritization, based on toxicological data and adverse outcomes, to pilot studies for their analytical, physiological, and epidemiological validation. We present the example of one study that demonstrated the mediating role of the effect biomarker status of brain-derived neurotrophic factor BDNF in the longitudinal association between infant bisphenol A (BPA) exposure and behavioral function in adolescence. A panel of effect biomarkers has been implemented in the HBM4EU Aligned Studies as main outcomes, including traditional oxidative stress, reproductive, and thyroid hormone biomarkers. Novel biomarkers of effect, such as DNA methylation status of BDNF and kisspeptin (KISS) genes were also evaluated as molecular markers of neurological and reproductive health, respectively. A panel of effect biomarkers has also been applied in HBM4EU occupational studies, such as micronucleus analysis in lymphocytes and reticulocytes, whole blood comet assay, and malondialdehyde, 8-oxo-2'-deoxyguanosine and untargeted metabolomic profile in urine, to investigate, for example, biological changes in response to hexavalent chromium Cr(VI) exposure. The use of effect biomarkers in HBM4EU has demonstrated their ability to detect early biological effects of chemical exposure and to identify subgroups that are at higher risk. The roadmap developed in HBM4EU confirms the utility of effect biomarkers, and support one of the main objectives of HBM research, which is to link exposure biomarkers to mechanistically validated effect and susceptibility biomarkers in order to better understand the public health implications of human exposure to environmental chemicals.

The HBM4EU chromates study - Outcomes and impacts on EU policies and occupational health practices

Within the EU human biomonitoring initiative (HBM4EU), a targeted, multi-national study on occupational exposure to hexavalent chromium (Cr(VI)) was performed. Cr(VI) is currently regulated in EU under REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) and under occupational safety and health (OSH) legislation. It has recently been subject to regulatory actions to improve its risk management in European workplaces. Analysis of the data obtained within the HBM4EU chromates study provides support both for the implementation of these regulatory actions and for national enforcement programs and may also contribute to the updating of occupational limit values (OELs) and biological limit values for Cr(VI). It also provides useful insights on the contribution of different risk management measures (RMMs) to further reduce the exposure to Cr(VI) and may support the evaluation of applications for authorisation under REACH. Findings on chrome platers' additional per- and polyfluoroalkyl substances (PFAS) exposure highlight the need to also pay attention to this substance group in the metals sector. A survey performed to evaluate the policy relevance of the HBM4EU chromates study findings supports the usefulness of the study results. According to the responses received from the survey, the HBM4EU chromates study was able to demonstrate the added value of the human biomonitoring (HBM) approach in assessment and management of occupational exposure to Cr(VI). For future occupational studies, we emphasise the need for engagement of policy makers and regulators throughout the whole research process to ensure awareness, relevance and uptake of the results in future policies.

Trace Element Levels in Nails of Residents of Addis Ababa Are Shaped by Social Factors and Geography

The Akaki catchment in Ethiopia is home to Addis Ababa and about five million people. Its watercourses receive a variety of wastes released by the residents and industries. River water is being used for irrigation, livestock watering, and other domestic purposes. This study tested the hypothesis that the river pollution would be reflected in higher levels of trace elements in the nails of residents living in Akaki-Kality Sub-City in the downstream, as compared to those living in Gullele Sub-City in the upstream of the Akaki catchment. Samples were taken and subsequently analysed for metals using inductively coupled plasma optical emission spectrometry (ICP-OES). The mean concentrations of Fe, Zn, Cu, Mn, Ni, Cr, Pb, and As in nails from Akaki-Kality were 488 ± 49, 106 ± 10, 5.2 ± 0.3, 13 ± 1.5, 11 ± 8, 2.2 ± 0.3, 0.09 ± 0.01, and 0.16 ± 0.01 μg/g, respectively. Likewise, the concentrations of Fe, Zn, Cu, Mn, Ni, Cr, Pb, and As in nails from Gullele were 1035 ± 135, 251 ± 10, 6.6 ± 0.4, 31 ± 3.7, 7.4 ± 1.7, 2.0 ± 0.3, 0.63 ± 0.01, and 0.25 ± 0.01 μg/g, respectively. Co and Cd were not detected. Contrary to the initial hypothesis, higher metal levels were found in nails of residents living in the upstream rather than the downstream area of the catchment. In particular, the concentrations of Fe (p = 0.000), Zn (p = 0.01), and Mn (p = 0.000) were significantly elevated in nails from Gullele and also high in comparison with internationally reported values. Besides, geography and social factors, especially education level, correlated to trace metals in nails. Most of the elements were significantly lower in the nails of individuals with a university degree compared to those who were illiterate or only completed primary school.

Leachate decontamination through biological processes coupled to advanced oxidation: A review

The landfill leachate is considered a toxic effluent composed of recalcitrant contaminants that requires innovative alternatives for its decontamination. Coupling between advanced oxidation processes (AOPs) and aerobic biological treatments are highlighted in this research. Therefore, a bibliographic review of the research made from 2010 to 2021 was developed. These combined alternatives were applied in leachates, and it is oriented toward the analysis of knowledge gaps, trends, and future proposals of the treatment combined that contribute to researchers who wish to work on the subject. These kinds of treatments were chosen due to a bibliometric analysis made. Also, the information was searched in several scientific database. This work was found to be unpublished, as no reviews were found so far that agglomerate studies of coupling between photocatalytic and aerobic biological processes to treat leachates. Besides, AOPs are ideal for treating wastewater of complex composition, however, when it is used as the only treatment, they are usually unprofitable, which justifies their coupling with biological treatments. Subsequently, it was determined that the knowledge main gap is the lack of documentation of treatment costs, which makes it difficult to implement on a real scale. In addition to this, the couplings trends are toward doping with metallic and nonmetallic ions of the catalyst used in the photocatalytic process to improve the efficiency of these. Finally, future research should work on finding alternatives that allow the optimization of the resources used in the combined systems and on promoting the recovery of existing products in the leachate.Implications: Leachates generate several environmental impacts due to their toxic composition. Even when coupling between heterogeneous photocatalysis and biologic treatment can solve them, issues like cost analysis and the scaling-up factor have not been developed, and futures researchers should work on that. Besides, the trend founded in almost all investigations was the catalyst doping with metals and nonmetals ions, particularly when they use TiO2 because it gives the possibility of improving efficiencies just with a structural variation. Finally, these treatment combinations require more analyses and comparison of their remotion over emerging pollutants and their performance with new designs.

Plain metallic biomaterials: opportunities and challenges

The 'plainification of materials' has been conceptualized to promote the sustainable development of materials. This perspective, for the first time in the field of biomaterials, proposes and defines 'plain metallic biomaterials (PMBs)' with demonstrated research and application case studies of pure titanium with high strength and toughness, and biodegradable, fine-grained and high-purity magnesium. Then, after discussing the features, benefits and opportunities of PMBs, the challenges are analyzed from both technical and regulatory aspects. Regulatory perspectives on PMB-based medical devices are also provided for the benefit of future research, development and commercialization.

E-WASTE threatens health: The scientific solution adopts the one health strategy

The aggressively extractive advanced technology industry thrives on intensive use of non-renewable resources and hyper-consumeristic culture. The environmental impact of its exponential growth means extreme mining, hazardous labour practices including child labour, and exposure burden to inorganic and organic hazardous chemicals for the environment and current and future human generations. Globally, processes such as in-country reduce, reuse and recycle have so far received less attention than outer-circle strategies like the uncontrolled dumping of e-waste in countries that are unprotected by regulatory frameworks. Here, in the absence of infrastructures for sound hazardous e-waste management, the crude recycling, open burning and dumping into landfills of e-waste severely expose people, animal and the environment. Along with economic, political, social, and cultural solutions to the e-waste global problem, the scientific approach based on risk analysis encompassing risk assessment, risk management and risk communication can foster a technical support to resist transgenerational e-waste exposure and health inequalities. This paper presents the latest public health strategies based on the use of integrated human and animal biomonitoring and appropriate biomarkers to assess and manage the risk of e-waste embracing the One Health approach. Advantages and challenges of integrated biomonitoring are described, along with ad-hoc biomarkers of exposure, effect and susceptibility with special focus on metals and metalloids. Indeed, the safe and sustainable management of novel technologies will benefit of the integration and coordination of human and animal biomonitoring.

HBM4EU Chromates Study-Genotoxicity and Oxidative Stress Biomarkers in Workers Exposed to Hexavalent Chromium

A study was conducted within the European Human Biomonitoring Initiative (HBM4EU) to characterize occupational exposure to Cr(VI). Herein we present the results of biomarkers of genotoxicity and oxidative stress, including micronucleus analysis in lymphocytes and reticulocytes, the comet assay in whole blood, and malondialdehyde and 8-oxo-2′-deoxyguanosine in urine. Workers from several Cr(VI)-related industrial activities and controls from industrial (within company) and non-industrial (outwith company) environments were included. The significantly increased genotoxicity (p = 0.03 for MN in lymphocytes and reticulocytes; p < 0.001 for comet assay data) and oxidative stress levels (p = 0.007 and p < 0.001 for MDA and 8-OHdG levels in pre-shift urine samples, respectively) that were detected in the exposed workers over the outwith company controls suggest that Cr(VI) exposure might still represent a health risk, particularly, for chrome painters and electrolytic bath platers, despite the low Cr exposure. The within-company controls displayed DNA and chromosomal damage levels that were comparable to those of the exposed group, highlighting the relevance of considering all industry workers as potentially exposed. The use of effect biomarkers proved their capacity to detect the early biological effects from low Cr(VI) exposure, and to contribute to identifying subgroups that are at higher risk. Overall, this study reinforces the need for further re-evaluation of the occupational exposure limit and better application of protection measures. However, it also raised some additional questions and unexplained inconsistencies that need follow-up studies to be clarified.

Occupational Exposure to Hexavalent Chromium, Nickel and PAHs: A Mixtures Risk Assessment Approach Based on Literature Exposure Data from European Countries

Hexavalent chromium (Cr(VI)), nickel (Ni) and polycyclic aromatic hydrocarbons (PAHs) are genotoxic co-occurring lung carcinogens whose occupational health risk is still understudied. This study, conducted within the European Human Biomonitoring Initiative (HBM4EU), aimed at performing a mixtures risk assessment (MRA) based on published human biomonitoring (HBM) data from Cr(VI), Ni and/or PAHs occupational co-exposure in Europe. After data extraction, Risk Quotient (RQ) and Sum of Risk Quotients (SRQ) were calculated for binary and ternary mixtures to characterise the risk. Most selected articles measured urinary levels of Cr and Ni and a SRQ > 1 was obtained for co-exposure levels in welding activities, showing that there is concern regarding co-exposure to these substances. Similarly, co-exposure to mixtures of Cr(VI), Ni and PAHs in waste incineration settings resulted in SRQ > 1. In some studies, a low risk was estimated based on the single substances’ exposure level (RQ < 1), but the mixture was considered of concern (SRQ > 1), highlighting the relevance of considering exposure to the mixture rather than to its single components. Overall, this study points out the need of using a MRA based on HBM data as a more realistic approach to assess and manage the risk at the workplace, in order to protect workers’ health.

Biochemical and reproductive biomarker analysis to study the consequences of heavy metal burden on health profile of male brick kiln workers

The present study aims to assess the effect of a heavy metal burden on general health, biochemical parameters, an antioxidant enzyme, and reproductive hormone parameters in adult male brick kiln workers from Pakistan. The study participants (n = 546) provided demographic data including general health as well as body mass index. Blood was collected to quantitatively assess hematological, biochemical, and reproductive hormone parameters as well as heavy metal concentrations using both atomic absorption spectroscopy (AAS) and particle-induced X-ray emission (PIXE). The data showed that 10% of the brick kiln workers were underweight and 10% obese (P = 0.059), with workers also reporting multiple health issues. Heavy metal concentrations utilizing AAS revealed significantly (p = 0.000) higher levels of cadmium, chromium, and nickel, while PIXE detected more than permissible levels of Si, P, S, Cl, K, Ca, Zn, Ti (p = 0.052), Mn (p = 0.017), Fe (p = 0.055), Co (p = 0.011), Ni (p = 0.045), and Cu (p = 0.003), in the blood of kiln workers. Moreover, a significant increase in platelet count (P = 0.010), a decrease in sodium dismutase levels (p = 0.006), a major increase in reactive oxygen species (p = 0.001), and a reduction in protein content (p = 0.013) were evident. A significant increase in cortisol levels (p = 0.000) among the workers group was also observed. The concentration of LH and FSH increased significantly (p = 0.000), while that of testosterone decreased (p = 0.000) in the worker group compared with controls. A significant inverse relationship was found between cortisol, LH (r =  - 0.380), and FSH (r =  - 0.946), while a positive correlation between cortisol and testosterone was also evident (r = 0.164). The study concludes that increased heavy metal burden in the blood of brick kiln workers exposes them to the development of general and reproductive health problems due to compromised antioxidant enzyme levels, increased oxidative stress conditions, and a disturbing reproductive axis.

Metal biomonitoring using fractioned dust to investigate urinary and oxidative stress biomarkers among occupationally exposed chromite mine workers

Exposure to heavy metals has been associated with the generation of reactive oxygen species (ROS) among exposed individuals in occupational and environmental settings. Dust is considered a significant contributor to airborne metal exposure, and previous data suggest that their levels in dust may vary based on its particle sizes. However, no biomonitoring study has been reported so far to address the metal-induced oxidative stress using different dust fractions, particularly in occupational settings. We designed a systematic cross-sectional study involving 110 chromite mine workers stratified into loaders (n = 28), extractors (n = 47) and operators (n = 35), and controls (n = 30) to find out the association between dust-bound metal exposure and oxidative stress using urinary creatinine-adjusted metal level as a biomarker of metal exposure. Results suggested elevated urinary levels of Cr 51.34 ± 8.6 along with Pb 34.29 ± 4.39, Cd 21.1 ± 2.6, and Ni 18.98 ± 3.01 µg/g creatinine in exposed (extractor group) workers. Correlating metal levels with oxidative stress revealed elevated malondialdehyde (MDA) levels of 62.28 ± 5.52 nM/dl among the extractors showing high levels of lipid peroxidation. Furthermore, blood superoxide dismutase (SOD) was also found significantly correlated (P = 0.000) with urinary toxic metal levels among exposed workers. We report the association between metal exposure and oxidative stress in exposed mining workers that may give rise to workers' susceptibility towards genetic and non-genetic health implications. The current study emphasized on the need for exposure control measures in the chromite ore mining activity areas.

Blood chromium exposure, immune inflammation and genetic damage: Exploring associations and mediation effects in chromate exposed population

Both genetic damage and inappropriate immune function are relevant to cancer of hexavalent chromium [Cr(VI)]. However, its associations with immune response and genetic damage development are poorly understood. To explore their associations and mediating effects, 1249 participants were included from the Occupational Chromate Exposure Dynamic Cohort, and their blood Cr concentrations were measured as internal exposure. A set of biomarkers including urinary 8-hydroxy-2' - deoxyguanosine (8-OHdG), micronucleus frequency (MNF) and mitochondrial DNA copy number (mtCN) was developed to evaluate the landscape of genetic damage of Cr(VI). Serum C-reactive protein (CRP) and first component of complement q (C1q) were measured to reflect immune inflammation. Multivariate linear regression and mediation analyses were applied to assess the potential associations and mediation effects. It was found that blood Cr level showed significant dose-dependent relationships with increasing of MNF and urinary 8-OHdG, while negative association with CRP and C1q. Furthermore, a 1-unit increase in CRP was associated with decreases of - 0.765 to - 0.254 in MNF, - 0.400 to - 0.051 in urinary 8-OHdG. 4.97% of the association between blood Cr level and the increased MNF was mediated by CRP. 11.58% of the relationship between concentration of blood Cr and urinary 8-OHdG was mediated by C1q. These findings suggested that Cr(VI) exposures might prompt genetic damage, possibly partial via worsening immune inflammation.

Cr (III) genotoxicity and oxidative stress: An occupational health risk for leather tannery workers of South Asian developing countries

In the leather industry, Cr (III) is used as a basic tanning agent. The wastewater discharged from the tannery industry contains a high concentration of chromium. Recent studies indicate the genotoxic effects especially DNA damage and oxidative stress of Cr (III) in tannery workers. Cr (III) interacts with DNA to form DNA cross-links and DNA strand breaks. It also modifies the oxidative DNA base through the Haber–Weiss reaction. The present study is based on an overview of scientific literature and previous observations regarding the effects of tannery chromium effluents on exposed workers and the population in the vicinity. This study strongly suggests for use of a non-toxic substitute of chromium to be used for the tanning process and placement of tannery industries on the outskirts of the city. In South Asian developing countries like India, Pakistan and Bangladesh where the economy is strongly dependent on leather manufacturing industries, there is a need to spread proper information regarding the harmful effects of chromium toxicity to the workforce employed in the tannery and also to the people living in the surrounding area. Workers should be provided with the required safety protections like gloves, aprons, foot/shoe covers, masks, etc. Last but most important on an immediate basis is the installation of the proper efficient waste treatment plant, so that, waste should be treated before moving out of the industry.

Genotoxicity evaluation of medical devices: A regulatory perspective

This review critically evaluates our current regulatory understanding of genotoxicity testing and risk assessment of medical devices. Genotoxicity risk assessment of these devices begins with the evaluation of materials of construction, manufacturing additives and all residual materials for potential to induce DNA damage. This is followed by extractable and/or leachable (E&L) studies to understand the worst case and/or clinical exposures, coupled with risk assessment of extractables or leachables. The TTC (Threshold of Toxicological Concern) approach is used to define acceptable levels of genotoxic chemicals, when identified. Where appropriate, in silico predictions may be used to evaluate the genotoxic potentials of identifiable chemicals with limited toxicological data and above the levels defined by TTC. Devices that could not be supported by E&L studies are evaluated by in vitro genotoxicity studies conducted in accordance with ISO10993-3 and 33. Certain endpoints such as 'site of contact genotoxicity' that are specific for certain classes of medical devices are currently not addressed in the current standards. The review also illustrates the potential uses of recent advances to achieve the goal of robust genotoxicity assessment of medical devices which are being increasingly used for health benefits. The review also highlights the gaps for genotoxicity risk assessment of medical devices and suggests possible approaches to address them taking into consideration the recent advances in genotoxicity testing including their potential uses in biocompatibility assessment.

Recommendations and quality criteria for micronucleus studies with humans

Micronucleus (MN) analyses in peripheral blood lymphocytes and exfoliated cells from different organs (mouth, nose, bladder and cervix) are at present the most widely used approaches to detect damage of genetic material in humans. MN are extranuclear DNA-containing bodies, which can be identified microscopically. They reflect structural and numerical chromosomal aberrations and are formed as a consequence of exposure to occupational, environmental and lifestyle genotoxins. They are also induced as a consequence of inadequate intake of certain trace elements and vitamins. High MN rates are associated with increased risk of cancer and a range of non-cancer diseases in humans. Furthermore, evidence is accumulating that measurements of MN could be a useful tool for the diagnosis and prognosis of different forms of cancer and other diseases (inflammation, infections, metabolic disorders) and for the assessment of the therapeutic success of medical treatments. Recent reviews of the current state of knowledge suggest that many clinical studies have methodological shortcomings. This could lead to controversial findings and limits their usefulness in defining the impact of exposure concentrations of hazardous chemicals, for the judgment of remediation strategies, for the diagnosis of diseases and for the identification of protective or harmful dietary constituents. This article describes important quality criteria for human MN studies and contains recommendations for acceptable study designs. Important parameters that need more attention include sufficiently large group sizes, adequate duration of intervention studies, the exclusion of confounding factors which may affect the results (sex, age, body mass index, nutrition, etc.), the evaluation of appropriate cell numbers per sample according to established scoring criteria as well as the use of proper stains and adequate statistical analyses.

Inorganic elements in occupational settings: A review on the effects on telomere length and biology

The past decades have shown that telomere crisis is highly affected by external factors. Effects of human exposure to xenobiotics on telomere length (TL), particularly in their workplace, have been largely studied. TL has been shown to be an efficient biomarker in occupational risk assessment. This is the first review focusing on studies about the effects on TL from occupational exposures to metals (lead [Pb] and mixtures), and particulate matter (PM) related to inorganic elements. Data from 15 studies were evaluated regarding occupational exposure to metals and PM-associated inorganic elements and impact on TL. Potential complementary analyses and subjects' background (age, length of employment and gender) were also assessed. There was limited information on the correlations between work length and TL dynamics, and that was also true for the correlation between age and TL. Results indicated that TL is affected differently across the types of occupational exposure investigated in this review, and even within the same exposure, a variety of effects can be observed. Fifty-three percent of the studies observed decreased TL in occupational exposure among welding fumes, open-cast coal mine, Pb and PM industries workers. Two studies focused particularly on the levels of metals and association with TL, and both linear and non-linear associations were found. Interestingly, TL modifications were accompanied by increase in DNA damage in 7 out of 8 studies that investigated it, measured either by Cytokinesis-block Micronucleus Assay or Comet assay. Five studies also investigated oxidative stress parameters, and 4 of them found increased levels of oxidative damage along with TL impairment. Oxidative stress is one of the main mechanisms by which telomeres are affected due to their high guanine content. Our review highlights the need of further studies accessing TL in simultaneous occupational exposure to mixtures of xenobiotics.

Genotoxic effect induced by dried nicotiana tabacum leaves from tobacco barns (kiln-houses) in chinese hamster lung fibroblast cells (V79)

Nicotiana tabacum is the most cultivated tobacco species in the state of Rio Grande do Sul, Brazil. Workers who handle the plant are exposed to the leaf components during the harvesting process and when separating and classifying the dried leaves. In addition to nicotine, after the drying process, other components may be found including tobacco-specific nitrosamines, polycyclic aromatic hydrocarbons, as well as pesticides residues. The objective of this study was to examine the genotoxicity attributed to the aqueous extract of dried tobacco leaves obtained from tobacco barns using Chinese hamster lung fibroblast cells (V79) as a model system by employing alkaline comet assay, micronucleus (MN) and Ames test. MTT assay was used to assess cytotoxicity and establish concentrations for this study. Data demonstrated cell viability > 85% for concentrations of 0.625-5 mg/ml while the comet assay indicated a significant increase in DNA damage at all concentrations tested. A significant elevation of MN and nuclear buds (NBUD) was found for 5 mg/ml compared to control and other dry tobacco leaves concentrations (0.625-2.5 mg/ml). Mutagenicity was not found using the Salmonella/Microsome test (TA98, TA100, and TA102 strains) with and without metabolic activation. The concentration of inorganic elements was determined employing the PIXE technique, and 13 inorganic elements were detected. Using CG/MS nicotine amounts present were 1.56 mg/g dry tobacco leaf powder. Due to the observed genotoxicity in V79 cells, more investigations are needed to protect the health of tobacco workers exposed daily to this complex mixture of toxic substances present in dry tobacco leaves.

Biomarkers of effect as determined in human biomonitoring studies on hexavalent chromium and cadmium in the period 2008-2020

A number of human biomonitoring (HBM) studies have presented data on exposure to hexavalent chromium [Cr(VI)] and cadmium (Cd), but comparatively few include results on effect biomarkers. The latter are needed to identify associations between exposure and adverse outcomes (AOs) in order to assess public health implications. To support improved derivation of EU regulation and policy making, it is of great importance to identify the most reliable effect biomarkers for these heavy metals that can be used in HBM studies. In the framework of the Human Biomonitoring for Europe (HBM4EU) initiative, our study aim was to identify effect biomarkers linking Cr(VI) and Cd exposure to selected AOs including cancer, immunotoxicity, oxidative stress, and omics/epigenetics. A comprehensive PubMed search identified recent HBM studies, in which effect biomarkers were examined. Validity and applicability of the markers in HBM studies are discussed. The most frequently analysed effect biomarkers regarding Cr(VI) exposure and its association with cancer were those indicating oxidative stress (e.g., 8-hydroxy-2'-deoxyguanosine (8-OHdG), malondialdehyde (MDA), glutathione (GSH)) and DNA or chromosomal damage (comet and micronucleus assays). With respect to Cd and to some extent Cr, β-2-microglobulin (B2-MG) and N-acetyl-β-D-glucosaminidase (NAG) are well-established, sensitive, and the most common effect biomarkers to relate Cd or Cr exposure to renal tubular dysfunction. Neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule (KIM)-1 could serve as sensitive biomarkers of acute kidney injury in response to both metals, but need further investigation in HBM studies. Omics-based biomarkers, i.e., changes in the (epi-)genome, transcriptome, proteome, and metabolome associated with Cr and/or Cd exposure, are promising effect biomarkers, but more HBM data are needed to confirm their significance. The combination of established effect markers and omics biomarkers may represent the strongest approach, especially if based on knowledge of mechanistic principles. To this aim, also mechanistic data were collected to provide guidance on the use of more sensitive and specific effect biomarkers. This also led to the identification of knowledge gaps relevant to the direction of future research.

Use of the alkaline comet assay for monitoring genotoxic effects of arsenic in human populations

The alkaline comet assay has been widely used to determine genotoxicity in human populations exposed to arsenic. The sample sizes of earlier studies were usually small, and inconsistent results were found. Meta-analyses can merge the results of multiple studies of the same type and increase the credibility of the conclusion by increasing the sample size. Thus, to investigate the monitoring effect of alkaline comet assay on genotoxicity for arsenic exposed population, meta-analyses were performed. Thirteen studies were found to meet the inclusion criteria and were included in this study; of them, twelve articles were of medium quality (15-20 points), only one study was of high quality (21-27 points). Meta-analyses showed that the overall estimates of Mean Ratio (MR, defined as the mean value of the response in the exposed group divided by that in the reference group) were 2.81(95 % confidence interval (CI) 1.93-4.10); 2.37(95 % CI, 1.73-3.26), and 1.69(95 %CI, 1.29-2.20) for comet tail length, % tail DNA, and tail moment, respectively. This shows that the level of DNA damage in arsenic exposed population is significantly higher than that in control populations. A meta-analysis of the correlation coefficients showed that the overall estimate was 0.52 (95 %CI, 0.48∼0.56, P<0.05) with all correlation coefficients included, but it changed to 0.24 (95 %CI, 0.17∼0.28, P<0.05) when two abnormal correlation coefficients were excluded, suggesting there was a positive correlation between arsenic load in vivo and DNA damage, but the overall estimate value of coefficients was unstable. Therefore, we conclude that the alkaline comet assay can be used as an effective genotoxic biomonitoring tool for arsenic-exposed populations. However, more and higher-quality studies are still needed to verify its actual application value.

Genotoxic Activity of Particulate Matter and In Vivo Tests in Children Exposed to Air Pollution

The aim of this paper was to investigate the relationship between micronuclei and DNA damage in children's buccal mucosa cells and the genotoxicity and mutagenicity of the different sized fractions of particulate matter as well as the concentration of PAHs (polycyclic aromatic hydrocarbons) and metals in particulate matter. Air particulate matter was collected by high volume samplers located near the schools attended by the children on the same days of biological samplings. The mutagenic activity was assessed in different cells in in vitro tests (Ames test on bacteria and comet test on leukocytes). Our study showed weak positive correlations between (a) the mutagenicity of the PM_0.5 fraction and PAHs and (b) the micronuclei test of children's buccal cells and PAHs detected in PM_0.5 and PM_0.5-3 fractions. A positive correlation was also found between in vitro comet test on leukocytes and PAHs in the PM_3-10 fraction. No correlation was observed for metal concentrations in each PM fraction.

Towards a systematic use of effect biomarkers in population and occupational biomonitoring

Effect biomarkers can be used to elucidate relationships between exposure to environmental chemicals and their mixtures with associated health outcomes, but they are often underused, as underlying biological mechanisms are not understood. We aim to provide an overview of available effect biomarkers for monitoring chemical exposures in the general and occupational populations, and highlight their potential in monitoring humans exposed to chemical mixtures. We also discuss the role of the adverse outcome pathway (AOP) framework and physiologically based kinetic and dynamic (PBK/D) modelling to strengthen the understanding of the biological mechanism of effect biomarkers, and in particular for use in regulatory risk assessments. An interdisciplinary network of experts from the European chapter of the International Society for Exposure Science (ISES Europe) and the Organization for Economic Co-operation and Development (OECD) Occupational Biomonitoring activity of Working Parties of Hazard and Exposure Assessment group worked together to map the conventional framework of biomarkers and provided recommendations for their systematic use. We summarized the key aspects of this work here, and discussed these in three parts. Part I, we inventory available effect biomarkers and promising new biomarkers for the general population based on the H2020 Human Biomonitoring for Europe (HBM4EU) initiative. Part II, we provide an overview AOP and PBK/D modelling use that improved the selection and interpretation of effect biomarkers. Part III, we describe the collected expertise from the OECD Occupational Biomonitoring subtask effect biomarkers in prioritizing relevant mode of actions (MoAs) and suitable effect biomarkers. Furthermore, we propose a tiered risk assessment approach for occupational biomonitoring. Several effect biomarkers, especially for use in occupational settings, are validated. They offer a direct assessment of the overall health risks associated with exposure to chemicals, chemical mixtures and their transformation products. Promising novel effect biomarkers are emerging for biomonitoring of the general population. Efforts are being dedicated to prioritizing molecular and biochemical effect biomarkers that can provide a causal link in exposure-health outcome associations. This mechanistic approach has great potential in improving human health risk assessment. New techniques such as in silico methods (e.g. QSAR, PBK/D modelling) as well as 'omics data will aid this process. Our multidisciplinary review represents a starting point for enhancing the identification of effect biomarkers and their mechanistic pathways following the AOP framework. This may help in prioritizing the effect biomarker implementation as well as defining threshold limits for chemical mixtures in a more structured way. Several ex vivo biomarkers have been proposed to evaluate combined effects including genotoxicity and xeno-estrogenicity. There is a regulatory need to derive effect-based trigger values using the increasing mechanistic knowledge coming from the AOP framework to address adverse health effects due to exposure to chemical mixtures. Such a mechanistic strategy would reduce the fragmentation observed in different regulations. It could also stimulate a harmonized use of effect biomarkers in a more comparable way, in particular for risk assessments to chemical mixtures.

Cobalt–Chromium Dental Alloys: Metal Exposures, Toxicological Risks, CMR Classification, and EU Regulatory Framework

During the 20th century, metal alloys have assumed an important role as restorative materials. Among existing examples, cobalt–chromium (Co–Cr) alloys increasingly began to be used in medicine and especially in dentistry. Their success is mainly due to their mechanical properties such as stiffness, strength and corrosion resistance, thus allowing a high biocompatibility. There are quite meaningful data on the corrosion and toxicity of Co–Cr alloys for their use in restorative materials such as dental prostheses. Toxicological studies following Co and Cr exposures in the oral cavity are more difficult to conduct because there are many different situations leading to the release of metal ions and wear particles. Furthermore, the links between exposure and the appearance of local or systemic toxicity are not automatic. Since 2017, the European Union (EU) regulatory framework for Co–Cr alloys has been undergoing profound changes. A new EU Medical Devices Regulation (MDR) (2017/745) will be applied in May 2021 with the need to consider that Co metal is a new carcinogenic, mutagenic and toxic to reproduction (CMR) substance. On 18 February 2020, the 14th Adaptation to Technical Progress (ATP14) to the Classification, Labelling and Packaging (CLP) regulation was published, including the harmonised classification for Co metal as a CMR 1B substance. In this context, the use of Co might be forbidden if the medical devices are invasive and as soon as they include more than 0.1% (m/m) Co. This review provides a specific overview on Co–Cr dental alloys in terms of metal ions and wear particles release, toxicological risks, and the actual and new EU regulatory framework.

Dietary and lifestyle factors effect erythrocyte PIG-A mutant frequency in humans

It is well understood that poor diet and lifestyle choices can increase the risk of cancer. It is also well documented that cancer is a disease of DNA mutations, with mutations in key genes driving carcinogenesis. Measuring these mutations in a minimally invasive way may be informative as to which exposures are harmful and thus allow us to introduce primary preventative measures, in a bid to reduce cancer incidences. Here, we have measured mutations in the phosphatidylinositol glycan class A (PIG-A) gene in erythrocytes from healthy volunteers (n = 156) and from non-cancer patients attending the local endoscopy department (n = 144). The X-linked PIG-A gene encodes an enzyme involved in glycosylphosphatidylinositol (GPI) anchor synthesis. A silencing mutation in which leads to the absence of GPI anchors on the extracellular surface which can be rapidly assessed using flow cytometry. The background level of PIG-A mutant erythrocytes was 2.95 (95% CI: 2.59-3.67) mutant cells (10-6). Older age increased mutant cell frequency (P < 0.001). There was no difference in mutant cell levels between males and females (P = 0.463) or smokers and non-smokers (P = 0.186). In the endoscopy group, aspirin users had lower mutant frequencies (P = 0.001). Further information on diet and exercise was available for the endoscopy patient group alone, where those with a higher health promotion index score had lower mutant frequencies (P = 0.011). Higher dietary intake of vegetables reduced mutant cell levels (P = 0.022). Participants who exercised for at least 1 h a week appeared to have reduced mutant frequencies than those who did not exercise, although this was not statistically significant (P = 0.099). This low background level of mutant erythrocytes in a population makes this assay an attractive tool to monitor exposures such as those associated with lifestyles and diet, as demonstrated here.

DNA methylation changes in promoter region of CDKN2A gene in workers exposed in construction environment

PURPOSE

Construction workers are exposed to a mixture of substances in the workplace considered carcinogenic. This study aimed to characterise gene-specific changes in DNA methylation over the workweek in this population as this type of environmental exposure has not been studied extensively.

MATERIALS AND METHODS

We evaluated their DNA methylation in 4 gene-promoter regions (CDKN2A, RASSF1A, MLH1 and APC) and 2 repeat elements (ALU and LINE-1) in blood samples obtained on the first and fifth day of the same workweek of a group of 39 male construction workers. DNA methylation was measured by bisulphite-PCR-Pyrosequencing. We also measured the levels of trace elements in the whole blood by ICP-MS.

RESULTS

Only the CDKN2A gene had significant differences in the average methylation level between the first and fifth day of the workweek. We also observed that the levels of Cu, Pb, Se, Mn, and Ti decreased during the fifth day of exposure, and only lead, titanium and copper showed a low significant correlation with the methylation level mean for three specific CpG sites of the CDKN2A.

CONCLUSIONS

In summary, the data suggest that altered levels of CDKN2A methylation in construction workers may be a potential biomarker of recent exposure in this environment.

Carbon dot-based composites for catalytic applications

We summarize the construction methods and influencing factors of CDs-based composites and discuss their catalytic applications, including photocatalysis, chemical catalysis, peroxidase-like catalysis, Fenton-like catalysis and electrocatalysis.

Preclinical safety evaluation of the aqueous extract from Mangifera indica Linn. (Anacardiaceae): genotoxic, clastogenic and cytotoxic assessment in experimental models of genotoxicity in rats to predict potential human risks

ETHNOPHARMACOLOGICAL RELEVANCE

Medicinal plants widely used by the population contain significant concentrations of biologically active compounds and, although they have proven pharmacological properties, can cause DNA damage and develop fatal diseases.

AIM OF THE STUDY

The present study aimed to evaluate the genotoxic, cytotoxic potential and clastogenic effects of the aqueous extract from Mangifera indica leaves (EAMI) on rats submitted to experimental genotoxicity models and through the SMART test performed in Drosophila melanogaster.

MATERIAL AND METHODS

The comet assay and the micronucleus test were performed on peripheral and bone marrow blood, respectively, of Wistar rats, orally treated with EAMI at doses of 125, 250, 500 and 1000 mg/kg/bw for 28 days. In the SMART test, the standard cross between three mutant D. melanogaster strains was used. Larvae were treated with EAMI at different concentrations, and the wings of adult flies were evaluated for the presence/frequency of mutant spots and compared to the negative control group.

RESULTS

Phytochemical analysis of EAMI indicated high levels of flavonoids. The tests performed in rats showed that EAMI did not present significant genotoxic or clastogenic effects. The results showed a critical dose-dependent cytoprotective effect exerted by EAMI. This result was attributed to the high content of polyphenols and flavonoids. The biotransformation metabolites of EAMI did not present genotoxic activity, as demonstrated by the SMART test.

CONCLUSIONS

These results are relevant since they provide safety information about a plant species of great therapeutic, economical, nutritious and ethnopharmacological value for the population.

Setting up a collaborative European human biological monitoring study on occupational exposure to hexavalent chromium

The EU human biomonitoring initiative, HBM4EU, aims to co-ordinate and advance human biomonitoring (HBM) across Europe. Within its remit, the project is gathering new, policy relevant, EU-wide data on occupational exposure to relevant priority chemicals and developing new approaches for occupational biomonitoring. In this manuscript, the hexavalent chromium [Cr(VI)] study design is presented as the first example of this HBM4EU approach. This study involves eight European countries and plans to recruit 400 workers performing Cr(VI) surface treatment e.g. electroplating or stainless steel welding activities. The aim is to collect new data on current occupational exposure to Cr(VI) in Europe and to test new methods for Cr biomonitoring, specifically the analysis of Cr(VI) in exhaled breath condensate (EBC) and Cr in red blood cells (RBC) in addition to traditional urinary total Cr analyses. Furthermore, exposure data will be complemented with early biological effects data, including genetic and epigenetic effects. Personal air samples and wipe samples are collected in parallel to help informing the biomonitoring results. We present standard operational procedures (SOPs) to support the harmonized methodologies for the collection of occupational hygiene and HBM samples in different countries.

Metals and emerging contaminants in groundwater and human health risk assessment

Groundwaters are normally consumed without previous treatment and therefore the monitoring of contaminants in order to guarantee its safety is necessary. Thus, we aimed to evaluate the groundwater contamination by metals and emerging contaminants, seeking to understand the relationship between their presence in the groundwater and the use and land cover profile of Itaporã and Caarapó. In addition, the contaminant concentrations observed were compared with maximum permitted values (MPV) and/or with calculated water quality criteria (WQC) for human consumption to investigate possible human health risks due to the groundwater intake. We collected one groundwater sample from each of the 12 wells located in Itaporã and 11 wells located in Caarapó. The metals were analyzed using ICP-OES and the emerging contaminants using LC-MS/MS. At least 1 of the 9 metals analyzed was found in each of the samples. In 12 samples, the metal concentrations verified exceeded the MPV or calculated WQC. A risk to human health has been observed for metals Co, Mn, Cr, and Ni. The emerging contaminant concentrations found in some samples were low (ng/L) and probably did not pose health risks, but their presence in the groundwater showed the impact of agriculture and the inadequate disposal of domestic sewage in the wells of both cities.

Exposure to arsenic in utero is associated with various types of DNA damage and micronuclei in newborns: a birth cohort study

BACKGROUND

Growing evidence indicates that in utero arsenic exposures in humans may increase the risk of adverse health effects and development of diseases later in life. This study aimed to evaluate potential health risks of in utero arsenic exposure on genetic damage in newborns in relation to maternal arsenic exposure.

METHODS

A total of 205 pregnant women residing in arsenic-contaminated areas in Hanam province, Vietnam, were recruited. Prenatal arsenic exposure was determined by arsenic concentration in mother's toenails and urine during pregnancy and in umbilical cord blood collected at delivery. Genetic damage in newborns was assessed by various biomarkers of early genetic effects including oxidative/nitrative DNA damage (8-hydroxydeoxyguanosine, 8-OHdG, and 8-nitroguanine), DNA strand breaks and micronuclei (MN) in cord blood.

RESULTS

Maternal arsenic exposure, measured by arsenic levels in toenails and urine, was significantly increased (p <  0.05) in subjects residing in areas with high levels of arsenic contamination in drinking water. Cord blood arsenic level was significantly increased in accordance with maternal arsenic exposure (p <  0.001). Arsenic exposure in utero is associated with genotoxic effects in newborns indicated as increased levels of 8-OHdG, 8-nitroguanine, DNA strand breaks and MN frequency in cord blood with increasing levels of maternal arsenic exposure. Maternal toenail arsenic level was significantly associated with all biomarkers of early genetic effects, while cord blood arsenic levels associated with DNA strand breaks and MN frequency.

CONCLUSIONS

In utero arsenic exposure is associated with various types of genetic damage in newborns potentially contributing to the development of diseases, including cancer, later in life.

Chromium(VI) promotes cell migration through targeting epithelial-mesenchymal transition in prostate cancer

Chromium (Cr) is widely used in industry, making its toxicity a matter of concern. Although hexavalent Cr [Cr(VI)] can promote cancer cell proliferation in several cancers, there is little evidence implicating Cr(VI) in cancer cell migration, especially in prostate cancer. We show that the Cr concentration is higher in the serum of prostate cancer patients, and is closely associated with unfavorable outcomes for the patients. Additionally, low dose trivalent Cr [Cr(III)] exposure has no obvious carcinogenic effects in prostate cancer. However, Cr(VI) can promote proliferation and invasion of prostate cancer cell line PC3 cells in vitro and in vivo. In seeking the molecular mechanism of Cr(VI) exposure on cancer progression, we found that Cr(VI) could down-regulate the epithelial protein marker, E-cadherin, and up-regulate mesenchymal protein markers, such as N-cadherin and Snail. Together, these data indicate that Cr(VI) is a newly verified carcinogen in prostate cancer, and can promote cell migration by affecting the Epithelial-Mesenchymal Transition (EMT) pathway. Thus, inhibition of Cr(VI)-EMT signaling is a prospective approach toward limiting prostate tumor progression.

Geospatial analysis of residential proximity to open-pit coal mining areas in relation to micronuclei frequency, particulate matter concentration, and elemental enrichment factors

During coal surface mining, several activities such as drilling, blasting, loading, and transport produce large quantities of particulate matter (PM) that is directly emitted into the atmosphere. Occupational exposure to this PM has been associated with an increase of DNA damage, but there is a scarcity of data examining the impact of these industrial operations in cytogenetic endpoints frequency and cancer risk of potentially exposed surrounding populations. In this study, we used a Geographic Information Systems (GIS) approach and Inverse Distance Weighting (IDW) methods to perform a spatial and statistical analysis to explore whether exposure to PM_2.5 and PM₁₀ pollution, and additional factors, including the enrichment of the PM with inorganic elements, contribute to cytogenetic damage in residents living in proximity to an open-pit coal mining area. Results showed a spatial relationship between exposure to elevated concentrations of PM_2.5, PM₁₀ and micronuclei frequency in binucleated (MNBN) and mononucleated (MNMONO) cells. Active pits, disposal, and storage areas could be identified as the possible emission sources of combustion elements. Mining activities were also correlated with increased concentrations of highly enriched elements like S, Cu and Cr in the atmosphere, corroborating its role in the inorganic elements pollution around coal mines. Elements enriched in the PM_2.5 fraction contributed to increasing of MNBN but seems to be more related to increased MNMONO frequencies and DNA damage accumulated in vivo. The combined use of GIS and IDW methods could represent an important tool for monitoring potential cancer risk associated to dynamically distributed variables like the PM.

Cr(VI)-induced methylation and down-regulation of DNA repair genes and its association with markers of genetic damage in workers and 16HBE cells

To examine the mechanism of hexavalent chromium [Cr(VI)]-induced carcinogenesis, a cross-sectional study in workers with or without exposure to Cr(VI) as well as in vitro administration of Cr(VI) in 16HBE cells was conducted. We explored the associations between Cr(VI) exposure, methylation modification of DNA repair genes and their expression levels, and genetic damage. Results showed that hypermethylation of CpG sites were observed in both occupationally exposed workers and 16HBE cells administrated Cr(VI). DNA damage markers including 8-hydroxydeoxyguanosine (8-OHdG) and micronucleus frequency in Cr(VI)-exposed workers were significantly higher than the control group. Among workers, blood Cr concentration was positively correlaed with the methylation level of CpG sites in DNA repair genes including CpG6,7, CpG8, CpG9,10,11 of MGMT, CpG11 of HOGG1; CpG15,16,17, CpG19 of RAD51, and genetic damage markers including 8-OHdG and micronucleus frequency. Significant negative association between methylation levels of CpG sites in DNA repair genes and corresponding mRNA was also observed in 16HBE cells. This indicated that Cr(VI) exposure can down-regulate DNA repair gene expression by hypermethylation, which leads to enhanced genetic damage. The methylation level of these CpG sites of DNA repair genes can be potential epigenetic markers for Cr(VI)-induced DNA damage.

Occupational Exposure to Pesticides in Tobacco Fields: The Integrated Evaluation of Nutritional Intake and Susceptibility on Genomic and Epigenetic Instability

Pesticides used at tobacco fields are associated with genomic instability, which is proposed to be sensitive to nutritional intake and may also induce epigenetic changes. We evaluated the effect of dietary intake and genetic susceptibility polymorphisms in MTHFR (rs1801133) and TERT (rs2736100) genes on genomic and epigenetic instability in tobacco farmers. Farmers, when compared to a nonexposed group, showed increased levels of different parameters of DNA damage (micronuclei, nucleoplasmic bridges, and nuclear buds), evaluated by cytokinesis-block micronucleus cytome assay. Telomere length (TL) measured by quantitative PCR was shorter in exposed individuals. Global DNA methylation was significantly decreased in tobacco farmers. The exposed group had lower dietary intake of fiber, but an increase in cholesterol; vitamins such as B6, B12, and C; β-carotene; and α-retinol. Several trace and ultratrace elements were found higher in farmers than in nonfarmers. The MTHFR CT/TT genotype influenced nucleoplasmic bridges, nuclear buds, and TL in the exposed group, whereas TERT GT/TT only affected micronucleus frequency. We observed a positive correlation of TL and lipids and an inverse correlation of TL and fibers. The present data suggest an important role of dietary intake and subjects' genetic susceptibility to xenobiotics-induced damages and epigenetic alterations in tobacco farmers occupationally exposed to mixtures of pesticides.

Socio-demographic, lifestyle, and dietary determinants of essential and possibly-essential trace element levels in adipose tissue from an adult cohort

There is increasing evidence linking levels of trace elements (TEs) in adipose tissue with certain chronic conditions (e.g., diabetes or obesity). The objectives of this study were to assess concentrations of a selection of nine essential and possibly-essential TEs in adipose tissue samples from an adult cohort and to explore their socio-demographic, dietary, and lifestyle determinants. Adipose tissue samples were intraoperatively collected from 226 volunteers recruited in two public hospitals from Granada province. Trace elements (Co, Cr, Cu, Fe, Mn, Mo, Se, V, and Zn) were analyzed in adipose tissue by high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS). Data were collected on socio-demographic characteristics, lifestyle, diet, and health status by face-to-face interview. Predictors of TE concentrations were assessed by using multivariable linear and logistic regression. All TEs were detected in all samples with the exception of Se (53.50%). Iron, zinc, and copper showed the highest concentrations (42.60 mg/kg, 9.80 mg/kg, and 0.68 mg/kg, respectively). Diet was the main predictor of Cr, Fe, Mo, and Se concentrations. Body mass index was negatively associated with all TEs (β coefficients = -0.018 to -0.593, p = 0.001-0.090) except for Mn and V. Age showed a borderline-significant positive correlation with Cu (β = 0.004, p = 0.089). Residence in a rural or semi-rural area was associated with increased Co, Cr, Fe, Mo, Mn, V and Zn concentrations and with β coefficients ranging from 0.196 to 0.544 (p < 0.05). Furthermore, individuals with higher educational level showed increased Cr, Co, Fe and V concentrations (β coefficients = 0.276-0.368, p = 0.022-0.071). This is the first report on the distribution of these TEs in adipose tissue and on their determinants in a human cohort and might serve as an initial step in the elucidation of their clinical relevance.

Influence of diet in urinary levels of metals in a biomonitoring study of a child population of the Valencian region (Spain)

Pollution by trace elements and its possible effect on organisms has become a worldwide concern due to the increasing presence of trace elements in the environment and especially in the food chain. Exposure to chemicals has traditionally been measured using environmental samples, however, human biomonitoring brings a different perspective, in which all sources and exposure pathways are integrated. The objective of this paper is to discern the possible relationship between children's diet and the metals found in children urine. With this aim in mind, a total of 120 voluntaries participated in a diet survey carried out in a school-aged population (age 6-11) from the Valencian region. In addition, twenty trace elements were analysed in children urine (arsenic, antimony, barium, beryllium, caesium, cadmium, cobalt, copper, lead, manganese, mercury, molybdenum, nickel, platinum, selenium, thallium, thorium, uranium, vanadium and zinc). Results permitted to compare metal levels in urine with metal levels of other biomonitoring studies to conclude that values, including ours, were similar in most studies. On the other hand, children who ate more vegetables had the highest values in cadmium, copper, molybdenum, antimony, thallium, vanadium, and zinc, while those who ate more fish reached higher values in mercury. Finally, children who ate more cereals and baked products had higher values in total arsenic.

In vitro genotoxic effect of secondary minerals crystallized in rocks from coal mine drainage

Coal processing generates a large volume of waste that can damage human health and the environment. Often these wastes produce acid drainage in which several minerals are crystallized (evaporites). This study aimed to identify secondary minerals, as well as the genotoxic potential of these materials. The samples were collected at two sites along the Rocinha River in Santa Catarina state (Brazil): (1) directly from the source of the acid drainage (evaporite 1), and (2) on the river bank (evaporite 2). The samples were characterized by X-ray diffraction and by particle-induced X-ray emission techniques. In vitro genotoxicity testing using Comet assay and Micronucleus test in V79 cells was used to evaluate evaporite samples. Our study also used System Biology tools to provide insight regarding the influence of this exposure on DNA damage in cells. The results showed that the samples induced DNA damage for both evaporites that can be explained by high concentrations of chromium, iron, nickel, copper and zinc in these materials. Thus, this study is very important due to the dearth of knowledge regarding the toxicity of evaporites in the environment. The genetic toxicity of this material can be induced by increased oxidative stress and DNA repair inhibition.

Cytogenetic instability in populations with residential proximity to open-pit coal mine in Northern Colombia in relation to PM10 and PM2.5 levels

Epidemiological studies indicate that living in proximity to coal mines is correlated with numerous diseases including cancer, and that exposure to PM₁₀ and PM_2.5 components could be associated with this phenomenon. However, the understanding of the mechanisms by which PM exerts its adverse effects is still incomplete and comes mainly from studies in occupationally exposed populations. The aims of this study were to: (1) evaluate DNA damage in lymphocytes assessing the cytokinesis-block micronucleus cytome assay (CBMN-cyt) parameters; (2) identify aneugenic or clastogenic effects in lymphocytes of exposed populations using CREST immunostaining for micronuclei; (3) evaluate multi-elemental composition of atmospheric particulate matter; and (4) verify relation between the DNA damage and PM_2.5 and PM₁₀ levels around the mining area. Analysis revealed a significant increase in micronuclei frequency in binucleated (MNBN) and mononucleated (MNMONO) cells of individuals with residential proximity to open-pit coal mines compared to residents from non-mining areas. Correlation analysis demonstrated a highly significant association between PM_2.5 levels, MNBN frequencies and CREST+ micronuclei induction in exposed residents. These results suggest that PM_2.5 fraction generated in coal mining activities may induce whole chromosome loss (aneuploidy) preferentially, although there are also chromosome breaks. Analysis of the chemical composition of PM_2.5 by PIXE demonstrated that Si, S, K and Cr concentrations varied significantly between coal mining and reference areas. Enrichment factor values (EF) showed that S, Cr and Cu were highly enriched in the coal mining areas. Compared to reference area, mining regions had also higher concentrations of extractable organic matter (EOM) related to nonpolar and polar compounds. Our results demonstrate that PM_2.5 fraction represents the most important health risk for residents living near open-pit mines, underscoring the need for incorporation of ambient air standards based on PM_2.5 measures in coal mining areas.