Adverse health effects of child labor: high exposure to chromium and oxidative DNA damage in children manufacturing surgical instruments

The association between nasal mucosa bacteria and serum metals in children with nasal diseases

Allergic rhinitis (AR) and adenoid hypertrophy (AH) are common nasal diseases in children. Studies have shown that heavy metals are environmental risk factors for nasal diseases, and the pathogenic mechanisms may be related to dysregulation of nasal mucosal microbiota. However, it is unclear how heavy metal exposure relates to the nasal mucosal microbiota in nasal diseases. Therefore, we explored serum metal exposure levels and nasal mucosal microbiota composition in children with different nasal disease, and further studied the potential correlation between metal exposure and disease-related taxa. There were 64 children recruited for this study. The 23 metals concentrations in serum were measured by inductively coupled plasma mass spectrometry, and nasal mucosal bacteria was identified by 16S rRNA sequencing. Nasal diseases (AR and AH) in children were associated with alterations in the abundance and diversity of the nasal mucosal microbiota. The nasal microbiota of children with AR showed lower diversity, while the microbiota of children with AH showed higher diversity. Linear discriminant analysis Effect Size showed 108 differentially abundant taxa between AR and control groups, 35 differentially abundant taxa among large adenoid, moderate adenoid and small adenoid groups. The serum zinc concentration was negatively correlated with Pielou's eveness index and Simpson's Index in children classified by adenoid size. The spearman correlation analysis showed that multiple disease-related taxa were closely associated with metal concentrations in serum. Our findings may support a link between metal exposure and the diversity and composition of nasal bacteria in children with nasal disease, which present new evidence for the effects of metals on children health.

Assessment of heavy metals and associated oxidative stress in occupationally exposed workers from Bannu and Karak Districts in Pakistan

Heavy metals (HMs) are extensively found in occupationally exposed miners and industrial workers, which may cause serious health-related problems to the large workforce. In order to evaluate the impact of these toxic pollutants, we have investigated the effect of cadmium (Cd), chromium (Cr), copper (Cu), and lead (Pb) concentration on exposed workers of mining, and woolen textile mill and compared the findings with unexposed individuals. From each category like exposed workers (mining, and woolen mill textile site) and unexposed individuals, 50 blood samples were taken. The occurrence of HMs in a sample was investigated through atomic absorption spectrometry while the oxidative stress marker malondialdehyde (MDA) and antioxidant enzyme statuses such as superoxide dismutase (SOD) and catalase (CAT) were analyzed in exposed and control samples. The results showed significant (p < 0.05) variation in Cd, Cr, Cu, and Pb levels in exposed and control samples. The concentration of Cd in the blood of WMWs, KMWs, and control group was 5.75, 3.89, and 0.42 μg/dL, respectively. On the other hand, the concentration of Pb in the blood of WMWs, MWs, and control was 32.34, 24.39, and 0.39 µg/dL while the concentrations of Cr and Cu in the blood of WMWs, MWs, and control group were 11.61 and 104.14 μg/dL, 4.21 and 113.21 μg/dL, 0.32 and 65.53 μg/dL, respectively. An increase in MDA was recorded in the exposed workers' group as compared to control subjects, whereas SOD and CAT activities decreased. Meanwhile, MDA was significantly and positively (p < 0.01) correlated with HMs, while negative significant correlations were found among HMs with SOD and CAT.

Demographic and anthropometric characteristics and their effect on the concentration of heavy metals (arsenic, lead, chromium, zinc) in children and adolescents

Background

Biomonitoring is a well-established method for assessing people's exposure to contaminants in the environment. Many non-communicable diseases can be prevented or aggravated by physiologically monitoring heavy metals in biological matrices such as urine, evaluating their association with non-communicable diseases, and attempting to limit exposure to them. The focus of this research was to determine the association between potentially toxic elements (PTE) such as arsenic (As), lead (Pb), chromium (Cr), and zinc (Zn) urine concentrations and anthropometric indices and demographic data in children and adolescents aged 6-18 years in Kerman, Iran.

Methods

106 children and adolescents aged 6-18 years in Kerman were randomly selected. A questionnaire was used to acquire demographic information from the participants' parents. Height, weight, and waist circumference (WC) were all assessed, as well as body mass index (BMI) and BMI Z-score. Induced Coupled Plasma Mass Spectrometry (ICP/MS) was used to quantify As, Pb, Cr, and Zn concentrations in participants' urine.

Results

The geometric mean concentrations were As (38.72 ± 39.30), Pb (19.58 ± 22.91), Cr (1.06 ± 0.28), and Zn (344.72 ± 288.16) μg/creatinine. Boys aged 12-18 years old had higher mean concentration of As than boys aged 6-11 years old (p = 0.019) according to two measurement standards, μg/L, and μg/creatinine, whereas girls had no significant difference. In general, there was a strong association between parental education and metal concentrations of As, Pb, and Cr. As, Pb, and Zn (μg/creatinine) had a significant positive association with BMI z-score and BMI. As, Pb, and Zn metals were shown to have a substantial positive association (p < 0.001). There was no evidence of an association between the metals evaluated and WC.

Conclusions

The findings of this study generally showed that there was a significant association between demographic characteristics and exposure to these metals in children and adolescents, indicating that these people were exposed to these metals, which can harm their health. As a result, the pathways of exposure to metals must be limited.

Genotoxic Biomonitoring in Children Living near the El Fraile Mine Tailings in Northern Guerrero State, Mexico

A genotoxic study was conducted with 101 elementary school children (56 girls and 45 boys) in the 6-7, 8-9, and 10-12 age ranges from El Fraile rural community, which is located beside the El Fraile mine tailings in Taxco of Alarcon City, in northern Guerrero State, Mexico. For this, we used the alkaline comet assay in exfoliated buccal mucosa cells, scoring three genotoxic parameters: tail intensity, tail moment, and tail length. Additionally, we detected oxidative DNA damage through urinary 8-OHdG levels by enzyme-linked immunosorbent assay. We also evaluated a control group consisting of 101 children in the same age ranges from Chilpancingo City, Guerrero, who had never lived near mining zones. Genotoxic results showed that there was a significant increase in three genotoxic parameters and urinary 8-OHdG levels in the exposed children group compared with the control group. Analysis of MANOVA revealed that boys aged 8 and 9 years had higher DNA damage than girls from the same exposure group, and Spearman's analysis identified a positive correlation between DNA damage and sex and age. This study provides the first valuable genotoxic data in children living in areas with environmental pollution.

Work-related injuries among 5 - 17 years-old working children in Egypt: findings from a national child labor survey

Background

Egypt has agreed and ratified international regulations that strict child labor. However, the country still struggles with high prevalence of child labor and the associated negative social and health effects. The objective of this study was to identify the prevalence and determinants of work-related injuries among working children in Egypt.

Methods

This study involved a secondary data analysis of the National Child Labor Survey (NCLS) conducted in 2010 by The Central Agency for Public Mobilization and Statistics (CAPMAS) in Egypt with technical and financial support from the ILO’s International Program on the Elimination of Child Labor (IPEC) through its Statistical Information and Monitoring Program on Child Labor (SIMPOC). The total number of working children who responded to questions of work-related injuries in the NCLS child questionnaire was 7485 children.

Results

The prevalence of work-related injuries among working children in Egypt was estimated as 24.1% (95% CI: 22.0%—26.2%), of whom the majority were superficial wounds (87.3%). Among children who reported work-related injuries, 57.9% did not stop work or schooling because of the most serious injury, while 39.6% had stopped temporarily and 2.6% had stopped completely. The main determinants of work-related injuries among working children in the study sample were gender (boys), age of starting work (5–11 years), type of main economic activity (industry and services), type of main workplace (plantation, farms, or garden), the average work hours per week (28 h or more), and exposure to ergonomic and safety, and chemical hazards at work.

Conclusions

The estimated high prevalence of work-related injuries among working children aged 5–17 years in Egypt raises the health risks concerns associated with child labor. Findings of this study on the determinants of work-related injuries could guide policies and interventions to combat child labor and the associated health risks, including work-related injuries.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-13689-6.

Reproductive Hormones Imbalance, Germ Cell Apoptosis, Abnormal Sperm Morphophenotypes and Ultrastructural Changes in Testis of African Giant Rats (Cricetomys gambianus) Exposed to Sodium Metavanadate Intoxication

Environmental exposure to vanadium has been on the increase in recent time. This metal is a known toxicant. The current study was conducted to investigate the reproductive toxicity of sodium metavanadate (SMV) in male African giant rats. Administration of SMV was done intraperitoneally daily for 14 consecutive days at a dosage of 3 mg/kg body weight. Sterile water was administered to the control group. Serum reproductive hormones, sperm reserve and quality as well as testicular ultrastructural changes following SMV treatment were analysed. Results showed SMV-exposed AGR group had statistically decreased concentrations of testosterone (4.7 ng/ml), FSH (3.4 IU/L) and LH (3.8 IU/L). Also, SMV-treated group had statistically decreased sperm motility and mass activity with increased percentage of abnormal morphophenotypes of spermatozoa and upregulation of P53 immunopositive cells. Ultrastructural study revealed vacuolation of germ and Sertoli cells cytoplasm and nucleus, and mitochondrial swelling and vacuolations were also observed. There was severe disintegration of the seminiferous tubules, atrophy and degeneration of myeloid cells and apoptosis of the Leydig, Sertoli and germ cells. In conclusion, intraperitoneal SMV exposure exerts severe adverse effects on some serum reproductive hormones, reduction in the sperm reserve and quality, apoptosis and degenerative changes of the Leydig, Sertoli and germ cells which can lead to infertility.

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.

The Health Impacts of Hazardous Chemical Exposures among Child Labourers in Low- and Middle-Income Countries

Of 218 million working children worldwide, many are suspected to be exposed to hazardous chemicals. This review aims to synthesize reported evidence over the last two decades on chemical exposure and adverse health consequences in children labourers in low- and middle-income Countries (LMIC). Included studies investigated health outcomes related to chemical exposures among child labourers aged 5-18 in LMIC. Twenty-three papers were selected for review, focusing on pesticides (n = 5), solvents (n = 3), metals (n = 13) and persistent organic pollutants (POPs) (n = 2). Adverse health effects identified among child labourers included abnormal biomarkers, for example elevated blood and urine chemical concentrations, neurobehavioural deficits and neurological symptoms, mental health issues, oxidative stress and DNA damage, poor growth, asthma, and hypothyroidism. Workplace exposure to chemicals has pernicious health effects on child labourers. Large research gaps exist, in particular for long-term health impacts through chronic conditions and diseases with long latencies. A sizeable disease burden in later life is likely to be directly attributable to chemicals exposures. We urge national and international agencies concerned with child labour and occupational health, to prioritize research and interventions aiming to reduce noxious chemical exposures in workplaces where children are likely to be present.

Perspectives of Genetic Damage and Epigenetic Alterations by Hexavalent Chromium: Time Evolution Based on a Bibliometric Analysis

Compounds containing hexavalent chromium [Cr(VI)] have been classified as Group I human carcinogens in 1990 by the International Agency for Research on Cancer, known to induce human lung cancers. To determine the nature of Cr(VI) carcinogenesis, much has been learned about genetic damage and epigenetic alterations. On the basis of bibliometric analysis of the available literature found between 1966 and 2020, the present study investigated the evolution of author keywords; provided a summary of relevant studies focused on populations, animals/plants, or cells; and depicted the co-operation among countries or institutions and research group development. Additionally, multiomics technology and bioinformatics analysis can be a valuable tool for figuring out new biomarkers from different molecular levels like gene, RNA, protein, and metabolite and ascertaining the mechanism pathways of Cr(VI) genotoxicity and carcinogenesis.

Pooled analysis of genotoxicity markers in relation to exposure in the Flemish Environment and Health Studies (FLEHS) between 1999 and 2018

BACKGROUND

The Flemish Environment and Health Studies (FLEHS) are human biomonitoring surveys running in Flanders since 1999. Additionally to biomarkers of exposure, markers of genotoxicity and oxidative stress have been measured, including the alkaline comet and micronucleus assay in peripheral whole blood cells, and urinary concentrations of 8-oxo-2'-deoxyguanosine (8-oxodG).

AIM

Exposure-effect associations were explored in a pooled dataset of nine different cross-sectional FLEHS surveys. Data of adolescents collected in a time frame of about 20 years (1999-2018) were compiled. The aim of the study was to examine whether increased variation in exposure, lifestyle and environmental factors would lead to more powerful and robust exposure-effect associations.

MATERIALS & METHODS

The biomarkers were measured in 2283 adolescents in the age range of 14-18 years. Exposure to polycyclic aromatic hydrocarbons [1-hydroxypyrene (1-OHP)], benzene (tt'-muconic acid), metals (arsenic, cadmium, copper, nickel, thallium, lead, chromium), persistent organochlorines and phthalates were assessed in blood or urine. Furthermore, outdoor air levels of particulate matter (PM₁₀ and PM_2.5) at the residences of the youngsters were calculated. Pooled statistical analysis was done using mixed models. Study-specific differences in the genotoxicity markers and in the strength/direction of the association were accounted for. This was done by incorporating the random factor 'study' and a random study slope (if possible). The exposure markers were centered around the study-specific mean in order to correct for protocol changes over time.

RESULTS

A significant association was observed for the urinary oxidative stress marker 8-oxodG, which was positively associated with 1-OHP (5% increase for doubling of 1-OHP levels, p = 0.001), and with urinary copper (26% increase for doubling of copper levels, p = 0.001), a metal involved in the Fenton reaction in biological systems. 8-oxodG was also associated with the sum of the metabolites of the phthalate di(2-ethylhexyl) phthalate (DEHP) (3% increase for doubling of the DEHP levels, p = 0.02). For those associations, data pooling increased the statistical power. However, some of the associations in the individual surveys, were not confirmed in the pooled analysis (such as comet assay and 8-oxodG vs. atmospheric PM; and 8-oxodG vs. urinary nickel). This may be due to inconsistencies in exposure-effect relations and/or variations in the pollutant mix over time and regions.

CONCLUSION

Pooled analysis including a large population of 2283 Flemish adolescents showed that 8-oxodG, a marker of oxidative DNA damage is a valuable marker to assess impact of daily life pollutants, such as PAHs, Cu and the phthalate DEHP.

Biochemical and ultrastructural changes in kidney and liver of African Giant Rats (Cricetomysgambianus, Waterhouse, 1840) exposed to intraperitoneal sodium metavanadate (vanadium) intoxication

We studied the hepatic and renal impact of sodium metavanadate (SMV) exposure in African giant rats (AGR). Twelve male AGR were used and divided into two groups. The control group received sterile water while the SMV-exposed group received 3 mg/kg SMV intraperitoneally for 14 days. SMV exposed AGR groups showed significantly decreased activities of serum AST, ALT, ALP and creatinine concentration but increased blood urea nitrogen (BUN), albumin and globulin concentrations. Kidney ultrastructure examination revealed atrophy of the glomerular tuft, loss of podocytes, distortions of the endothelium and glomerular basement membrane. The liver sinusoids fenestration phenotypes were abnormal. Hepatocytes exhibited hypertrophy with uneven, crenated and dentate nuclei. SMV exposure induced activation of monocytes, as well as Kupffer and fibrous cells. Alterations in glomerular podocytes and cell-cell and cell matrix contact and inflammatory liver fibrosis are key events in progressive glomerular failure and hepatic damage due to SMV intoxication.

Emission-related Heavy Metal Associated with Oxidative Stress in Children: Effect of Antioxidant Intake

Heavy metals, the common pollutants emitted from industrial activities, are believed to cause harmful effects, partially through the mechanism of elevated oxidative stress, and antioxidant intake has been hypothesized to provide a potential protective effect against oxidative stress. This study aims to investigate the heavy metal exposure and the associated oxidative damage of young children living near a petrochemical complex and to assess the protective effect of antioxidant intake. There were 168 children recruited from the kindergartens near a huge petrochemical complex, with 87 as the high exposure group and 81 as the low exposure group. Urinary concentrations of eleven metals were detected by inductively coupled plasma mass spectrometry, and four biomarkers of oxidative stress were measured in urine by liquid chromatography-tandem mass spectrometry. The food frequency questionnaire was collected to assess participants’ intake of antioxidants. Multiple linear regression was performed to determine the predictors of metals for oxidative stress and to measure the beneficial effect of antioxidants. Weighted quantile sum regression was performed to determine the contributors among metals to the oxidative stress. Results showed that high exposure group had significantly higher concentrations of chromium, manganese, nickel, arsenic, strontium, cadmium, and lead when compared to those in low exposure group. There was no obviously difference on the total antioxidant intake and dietary profile between two groups. The elevated levels of two oxidative stress markers were significantly associated with most of the urinary metal concentrations in all study subjects after adjusting confounders, while no significant association was found between oxidative stress and antioxidant intake. Among the metals, mercury and strontium showed the dominated contributions for elevated levels of oxidative stress. It concluded that higher metal exposure was associated with elevated oxidative stress but with no protective effect by antioxidant intake among the young children residents near a petrochemical industry.

Prenatal Exposure to Lead and Chromium is Associated with IL-13 Levels in Umbilical Cord Blood and Severity of Atopic Dermatitis: COCOA Study

There have been few studies investigating the association between atopic dermatitis (AD) and prenatal exposure to heavy metals. We aimed to evaluate whether prenatal exposure to heavy metals is associated with the development or severity of AD in a birth cohort study. A total of 331 subjects were followed from birth for a median duration of 60.0 months. The presence and severity of AD were evaluated at ages 6 and 12 months, and regularly once a year thereafter. The concentrations of lead, mercury, chromium, and cadmium in umbilical cord blood were measured by inductively coupled plasma mass spectrometry. Cord blood mononuclear cells (CBMCs) were isolated and stimulated for analysis of cytokine production using ELISA. Heavy metal levels in cord blood were not associated with the development of AD until 24 months of age. However, a positive correlation was observed between the duration of AD and lead levels in cord blood (p=0.002). AD severity was also positively associated with chromium concentrations in cord blood (p=0.037), while cord blood levels of lead, mercury, and cadmium were not significantly associated with AD severity (p=0.562, p=0.054, and p=0.055, respectively). Interleukin-13 production in CBMCs was positively related with lead and chromium levels in cord blood (p=0.021 and p=0.015, respectively). Prenatal exposure to lead and chromium is associated with the persistence and severity of AD, and the immune reaction toward a Th2 polarization.

An overview of the current progress, challenges, and prospects of human biomonitoring and exposome studies

Human Biomonitoring (HB), the process for determining whether and to what extent chemical substances penetrated our bodies, serves as a useful tool to quantify human exposure to pollutants. In cases of nutrition and physiologic status, HB plays a critical role in the identification of excess or deficiency of essential nutrients. In pollutant HB studies, levels of substances measured in body fluids (blood, urine, and breast milk) or tissues (hair, nails or teeth) aid in the identification of potential health risks or associated adverse effects. However, even as a widespread practice in several countries, most HB studies reflect exposure to a single compound or mixtures which are measured at a single time point in lifecycle. On the other hand, throughout an individual's lifespan, the contact with different physical, chemical, and social stressors occurs at varying intensities, differing times and durations. Further, the interaction between stressors and body receptors leads to dynamic responses of the entire biological system including proteome, metabolome, transcriptome, and adductome. Bearing this in mind, a relatively new vision in exposure science, defined as the exposome, is postulated to expand the traditional practice of measuring a single exposure to one or few chemicals at one-time point to an approach that addresses measures of exposure to multiple stressors throughout the lifespan. With the exposome concept, the science of exposure advances to an Environment-Wide Association Perspective, which might exhibit a stronger relationship with good health or disease conditions for an individual (phenotype). Thus, this critical review focused on the current progress of HB and exposome investigations, anticipating some challenges, strategies, and future needs to be taken into account for designing future surveys.

Gold and silver nanoparticles in resonance Rayleigh scattering techniques for chemical sensing and biosensing: a review

This review (with 116 refs.) summarizes the state of the art in resonance Rayleigh scattering (RRS)-based analytical methods. Following an introduction into the fundamentals of RRS and on the preparation of metal nanoparticles, a first large section covers RRS detection methods based on the use of gold nanoparticles, with subsections on proteins (albumin, bovine serum albumin and ovalbumin, glycoproteins, folate receptors, iron binding-proteins, G-proteins-coupled receptors, transmembrane proteins, epidermal growth factor receptors), on pesticides, saccharides, vitamins, heavy metal ions (such as mercury, silver, chromium), and on cationic dyes. This is followed by a section on RRS methods based on the use of silver nanoparticles, with subsections on the detection of nucleic acids and insecticides. Several Tables are presented where an RRS method is compared to the performance of other methods. A concluding section summarizes the current status, addresses current challenges, and gives an outlook on potential future trends. Graphical Abstract Change in the resonance Rayleigh scattering (RRS) intensity when mixing the nanoparticles with the specific analyte.

Evaluation of Benzene Exposure and Early Biomarkers of Kidney Damage in Children Exposed to Solvents Due to Precarious Work in Ticul, Yucatán, México

BACKGROUND

The child labor situation has been associated with precarious job conditions and poor health conditions because children are often exposed to unsafe work environments, stressful psycho-social work conditions, scarce or no access to protective services, and heavy work burdens.

OBJECTIVE

The aim of the study was to evaluate markers of exposure to benzene through the exposure biomarker trans, trans-muconic acid (tt-MA), and biomarkers of early renal damage in children who work in sites that are under precarious job conditions.

METHOD

Samples of urine were obtained from children (aged 6-12 years old) who resided in Ticul, Yucatan, Mexico. Exposure to benzene was assessed through trans, trans-muconic acid (t,t-MA). Evaluated renal damage biomarkers were: Cystatin-C (Cys-C), Osteopontin (OPN), α1-Microglobulin (α1-MG) and Neutrophil Gelatinase-Associated Lipocalin (NGAL).

FINDINGS

Children who live where the workplace is inside the dwelling presented higher mean levels of tt-MA (0.59 mg/g creatinine) compared with those who live away from the workshops (0.19 mg/g creatinine). Likewise, mean levels of NGAL (4.7, 5.2 ng/ml), albuminuria (10, 10 ng/ml), Cys-C (11.8, 7.5 ng/ml), OPN (224.4, 226.5 ng/ml) and α1-MG (96.6, 73.6 ng/ml) were found in children where the workplace was inside the dwelling and outside, respectively.

CONCLUSION

Our data indicate that the children who work under precarious job conditions are exposed to benzene, and they exhibit protein levels that suggest renal damage in a population in precarious working conditions. Therefore, the child population should be considered as the most vulnerable and susceptible to suffer adverse health effects.

Effect of Benzene Exposure on the Urinary Biomarkers of Nucleic Acid Oxidation in Two Cohorts of Gasoline Pump Attendants

(1) Background: The oxidized guanine derivatives excreted into urine, products of DNA and RNA oxidation and repair, are used as biomarkers of oxidative damage in humans. This study aims to evaluate oxidative damage in gasoline pump attendants occupationally exposed to benzene. Benzene is contained in the gasoline but it is also produced from traffic and from smoking. (2) Methods: Twenty-nine gasoline pump attendants from two major cities of Saudi Arabia and 102 from Italy were studied for urinary 8-oxo-7,8-dihydroguanine (8-oxoGua), 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodGuo), 8-oxo-7,8-dihydroguanosine (8-oxoGuo), and S-phenyl-mercapturic acid (SPMA) for benzene exposure and urinary cotinine for smoking status assessment by liquid chromatography-tandem mass spectrometry. Airborne benzene was also assessed in the Italian group by gas-chromatography with flame ionization detector (GC-FID). (3) Results: The results suggest that high levels of benzene exposure can cause an accumulation of SPMA and bring about the formation of the oxidation biomarkers studied to saturation. At low exposure levels, SPMA and oxidation biomarker levels were correlated among them and were associated with the smoking habit. (4) Conclusions: The study confirms the association between benzene exposure and the excretion of nucleic acid oxidation biomarkers and enhances the importance of measuring the smoking habit, as it can significantly influence oxidative damage, especially when the exposure levels are low.

Sustainability of artisanal mining of cobalt in DR Congo

The sustainability of cobalt is an important emerging issue because this critical base metal is an essential component of lithium-ion batteries for electric vehicles. More than half the world's cobalt mine production comes from the Katanga Copperbelt in DR Congo, with a substantial proportion (estimated at 15-20%) being extracted by artisanal miners. Here we show, in a case study performed in the town of Kolwezi, that people living in a neighbourhood that had been transformed into an artisanal cobalt mine, had much higher levels of cobalt in urine and blood than people living in a nearby control area. The differences were most pronounced for children, in whom we also found evidence of exposure-related oxidative DNA damage. It was already known that industrial mining and processing of metals have led to severe environmental pollution in the region. This field study provides novel and robust empirical evidence that the artisanal extraction of cobalt that prevails in the DR Congo may cause toxic harm to vulnerable communities. This strengthens the conclusion that the currently existing cobalt supply chain is not sustainable.

Sustainability of artisanal mining of cobalt in DR Congo

The sustainability of cobalt is an important emerging issue because this critical base metal is an essential component of lithium-ion batteries for electric vehicles. More than half the world's cobalt mine production comes from the Katanga Copperbelt in DR Congo, with a substantial proportion (estimated at 15-20%) being extracted by artisanal miners. Here we show, in a case study performed in the town of Kolwezi, that people living in a neighbourhood that had been transformed into an artisanal cobalt mine, had much higher levels of cobalt in urine and blood than people living in a nearby control area. The differences were most pronounced for children, in whom we also found evidence of exposure-related oxidative DNA damage. It was already known that industrial mining and processing of metals have led to severe environmental pollution in the region. This field study provides novel and robust empirical evidence that the artisanal extraction of cobalt that prevails in the DR Congo may cause toxic harm to vulnerable communities. This strengthens the conclusion that the currently existing cobalt supply chain is not sustainable.

Oxidative DNA damage mediates the association between urinary metals and prevalence of type 2 diabetes mellitus in Chinese adults

Previous publications have indicated that some metals are associated with an increased prevalence of type 2 diabetes mellitus (T2DM); however, the mechanisms remain largely unknown. This study aimed to quantify the associations of oxidative DNA damage with urinary metals and prevalence of T2DM among the general population, and further to assess the role of oxidative DNA damage in mediating the association of urinary metals with prevalence of T2DM. Diagnoses of T2DM were performed clinically or by measuring fasting levels of plasma glucose ≥7.0mmol/L. Concentrations of urinary metals and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in 2127 participants were measured using inductively coupled plasma-mass spectrometry and high-performance liquid chromatography. Relationships among urinary metals, 8-OHdG (a biomarker for oxidative DNA damage), and prevalence of T2DM were analyzed using mediation analysis. After adjusting for covariates, we found that the log-transformed levels of urinary copper, arsenic, selenium, molybdenum, and antimony were positively associated with prevalence of T2DM. Urinary 8-OHdG was not only positively correlated with copper, arsenic, selenium, and antimony in an upwardly trending, dose-responsive manner but was also positively associated with prevalence of T2DM (odds ratio (OR): 1.95; 95% CI: 1.17-3.24). Mediation analysis estimated that urinary 8-OHdG mediated 13.22% and 8.84% of associations between prevalence of T2DM and concentrations of urinary arsenic and antimony, respectively (all P value<0.05). Our findings suggested that urinary arsenic and antimony concentrations were associated with an increased prevalence of T2DM by a mechanism partly involving oxidative DNA damage.

Assessing exposure to metals using biomonitoring: Achievements and challenges experienced through surveys in low- and middle-income countries

In this narrative account based on a keynote presentation on exposure biomonitoring of metals in low- and middle-income countries (LMIC), we first briefly address practical issues that have arisen from our experience during the conduct of various surveys in LMIC. These have included the statistical handling of multiple pollutants in the same subject, the problem of correctly adjusting for urinary flow in spot samples of urine, and the possible external contamination of samples when doing field surveys in challenging environments. We then review and present selected results from surveys conducted in the mining area of Katanga in the Democratic Republic of Congo (DR Congo), where we documented high urinary levels of cobalt and other trace metals (arsenic, uranium) in people living close (<3 km) to mining or smelting operations (Banza et al., 2009). Consumption of contaminated foodstuffs (maize, legumes, fish) and, especially among children, dust ingestion proved to be the main sources of exposure to cobalt (Cheyns et al., 2014). Urinary biomonitoring studies among artisanal workers involved in mining cobalt, craftsmen working malachite, and workers processing gold ore revealed high to extremely high values of cobalt (largely exceeding the Biological Exposure Index of 15 μg/L), as well as other trace metals such as uranium, manganese, lead or mercury, depending on the type of jobs. This abundant biomonitoring data has been valuable to argue for improved enforcement of legislation to protect workers and citizens against the hazards posed by the mining activities in the area. Epidemiological studies have been undertaken and are ongoing to assess the human health impact of this pollution.

Effect of alkaline precipitation on Cr species of Cr(III)-bearing complexes typically used in the tannery industry

Various organic compounds extensively used in the leather industry could influence the performance of alkaline precipitation with Cr(III). This study focused on two typical Cr(III)-bearing complexes (Cr(III)-collagen and Cr(III)-citrate) ubiquitous in tannery effluent yet with distinct treatment efficiencies, as Cr(III) was much more difficult to remove in the Cr(III)-citrate solution. Comprehensive analytical methods were employed to explore the intrinsic mechanism. It was found that a lower removal efficiency towards Cr(III) was significantly associated with higher oligomers. The molecular size of the Cr(III)-citrate complex continued to increase with rising pH, making it larger overall than Cr(III)-collagen species. The growing oligomer moiety of dissolved Cr(III)-complex species could persist in the stronger basic pH range, leading to the large amount of residual Cr(III) in the Cr(III)-citrate system. Combining this result with potentiometric titration and X-ray photoelectron spectroscopy data, it was believed that the polymeric species other than monomers facilitated resisting the attack from hydroxide ions, and the postulated Cr(III)-citrate species towards higher oligomers were discovered. Beyond that, both charge neutralization and sweeping effects were presented among the gradually emerging flocs in the Cr(III)-collagen system together with the electric double layer compression effect derived from salinity, thus resulting in a larger floc size and higher Cr(III) removal efficiency in saline solutions.

Child labour and health: a systematic review

OBJECTIVES

This study aimed to synthesise the available knowledge, identify unexplored areas and discuss general limits of the published evidence. We focused on outcomes commonly hypothesised to be affected by child labour: nutritional status, harmful exposures and injuries.

METHODS

Four electronic databases (EMBASE, MEDLINE, Scopus, ISI Web of Science) were searched in November 2017. All articles published since 1996, without restrictions on language, were considered for inclusion.

RESULTS

Out of the 1090 abstracts initially identified by the search, 78 articles were selected for inclusion and reviewed. Most of the studies were conducted in Asia and South America, and only a third of them compared working children to a control group of non-working children. Child labour appears to be associated with poor nutritional status, diseases due to harmful exposures, and a higher prevalence of injuries.

CONCLUSIONS

Despite evidence for a negative relation between child work and health, the cross-sectional design of most studies limits the causal interpretation of existing findings. More rigorous observational studies are needed to confirm and better quantify these associations.

Potential health risk of heavy metals in the leather manufacturing industries in Sialkot, Pakistan

This is a systematical report on the potential health risk of heavy metals from the leather industries in Pakistan based on multiple biological matrices of the exposed workers and indoor dust samples. The adverse impacts of heavy metals on the oxidative enzyme and their risks to workers' health were also explored. Our results indicated that the level of Cr in indoor industrial dust was more than twice, compared to the background household dust. Blood, urine and hair samples of exposed workers showed significantly high concentrations of heavy metals, compared to those in the control group. Superoxide dismutase (SOD) level in the blood samples expressed significant positive correlation with Cr and Ni. Total hazard quotients (HQs)/hazard index (HI) were >1, and Cr (VI) exhibited higher cancer risks than that of Cd in the exposed workers. In addition, the PCA-MLR analysis confirmed that the industrial sections; cutting, shivering/crusting, and stitching were the principal contributors of heavy metals in the biological entities of the workers. Taken together, our results highlighted the occupationally exposed groups would likely to experience the potential health risks due to excessive exposure to the heavy metals from the leather industries.

Health hazards of child labor in the leather products and surgical instrument manufacturing industries of Sialkot, Pakistan

Child labor is a major challenge in the developing countries and comprehensive health hazard identification studies on this issue are still lacking. Therefore, the current study is an effort to highlight the health concerns of child labor exposed in the key small scale industries of Sialkot, Pakistan. Our findings revealed jolting levels of heavy metals in the urine, blood, serum, saliva, and hair samples collected from the exposed children. For example, in the urine samples, Cd, Cr, Ni, and Pb were measured at the respective concentrations of 39.17, 62.02, 11.94 and 10.53 μg/L in the surgical industries, and 2.10, 4.41, 1.04 and 5.35 μg/L in the leather industries. In addition, source apportionment revealed polishing, cutting, and welding sections in the surgical industries and surface coating, crusting, and stitching sections in the leather industries were the highest contributors of heavy metals in the bio-matrices of the exposed children, implying the dusty, unhygienic, and unhealthy indoor working conditions. Further, among all the bio-matrices, the hair samples expressed the highest bioaccumulation factor for heavy metals. In accordance with the heavy metal levels reported in the exposed children, higher oxidative stress was found in the children working in the surgical industries than those from the leather industries. Moreover, among heavy metals' exposure pathways, inhalation of industrial dust was identified as the primary route of exposure followed by the ingestion and dermal contact. Consequently, chemical daily intake (CDI), carcinogenic and non-carcinogenic hazard quotients (HQs) of heavy metals were also reported higher in the exposed children and were also alarmingly higher than the corresponding US EPA threshold limits. Taken all together, children were facing serious health implications in these industries and need immediate protective measures to remediate the current situation.

Evaluation of effects of melatonin and caffeic acid phenethyl ester on acute potassium dichromate toxicity and genotoxicity in rats

Objective:

The aim of this study is to investigate the possible protective effects of melatonin and caffeic acid phenethyl ester (CAPE) on potassium dichromate (K₂ Cr₂O₇)-induced nephrotoxicity and genotoxicity.

Methods:

A total of 40 Wistar albino rats were divided into five groups: control, K₂Cr₂O₇(K₂Cr₂O₇15 mg/kg, one dose, i.p.), K₂Cr₂O₇ + melatonin, K₂Cr₂O₇ + CAPE, and K₂Cr₂O₇ + melatonin + CAPE. Urine and blood samples were collected from rats before scarification. One kidney was collected for histopathological studies, and the other was stored at −80°C for further determination of catalase (CAT), superoxide dismutase (SOD), malondialdehyde (MDA), glutathione (GSH), glutathione S-transferase (GST), and glutathione reductase (GR) levels with spectrophotometric method. Comet assay was used to evaluate the genotoxicity.

Results:

We observed a significant amelioration in genotoxicity by melatonin and simultaneous melatonin + CAPE treatment compared to K₂Cr₂O₇ group (p₁, p₂< 0.05). SOD, CAT, GSH, GST, and MDA levels did not change when compared with controls. When K₂Cr₂O₇ applied group was treated with melatonin and CAPE, neither melatonin nor CAPE made any changes in kidney GSH, GST, SOD, and MDA levels (P > 0.05). We noted that treatment with CAPE and melatonin + CAPE together caused a significant decrease in renal tissue damage, an upregulation in the kidney CAT levels (P < 0.05) and a slight healing at GR levels when compared with the K₂Cr₂O₇ group.

Conclusion:

Our results revealed, CAPE and melatonin may have protective effects on K₂Cr₂O₇ induced nephrotoxicity and cellular damage in rats.

Environmental exposure and effects on health of children from a tobacco-producing region

Children may be environmentally exposed to several hazards. In order to evaluate the health of children living in a tobacco-producing region, different biomarkers of exposure and effect, as well as hematological parameters, were evaluated. Biomarkers of exposure to the following xenobiotics were assessed: pesticides, nicotine, toxic elements, and organic solvents. Oxidative damage markers malondialdehyde (MDA) and protein carbonyls (PCO), vitamin C, microalbuminuria (mALB) levels, and N-acetyl-β-D-glucosaminidase (NAG) activity were also evaluated. Peripheral blood samples and urine were collected from 40 children (6-12 years), at two different crop periods: in the beginning of pesticide applications (period 1) and in the leaf harvest (period 2). The Wilcoxon signed-rank test for paired data was used to evaluate the differences between both periods. Biomarkers of exposure cotinine in urine and blood chromium (Cr) levels were increased in period 1 when compared to period 2. Moreover, a significant reduced plasmatic activity of butyrylcholinesterase (BuChE) was observed in period 2 in relation to period 1. Blood Cr levels were above the recommended by WHO in both evaluations. The biomarkers MDA and PCO as well as the kidney dysfunction biomarker, mALB, presented levels significantly increased in period 1. Additionally, decreased lymphocytes and increased basophils were also observed. Cotinine was positively associated with PCO, and Cr was positively associated with PCO and MDA. The increased Cr levels were associated with decreased lymphocytes and increased basophils. Our findings demonstrate that children environmentally exposed to xenobiotics in rural area may present early kidney dysfunction, hematological alterations, as well as lipid and protein damages, associated with co-exposure to different xenobiotics involved in tobacco cultivation.

Environmental exposure to human carcinogens in teenagers and the association with DNA damage

BACKGROUND

We investigated whether human environmental exposure to chemicals that are labeled as (potential) carcinogens leads to increased (oxidative) damage to DNA in adolescents.

MATERIAL AND METHODS

Six hundred 14-15-year-old youngsters were recruited all over Flanders (Belgium) and in two areas with important industrial activities. DNA damage was assessed by alkaline and formamidopyrimidine DNA glycosylase (Fpg) modified comet assays in peripheral blood cells and analysis of urinary 8-hydroxydeoxyguanosine (8-OHdG) levels. Personal exposure to potentially carcinogenic compounds was measured in urine, namely: chromium, cadmium, nickel, 1-hydroxypyrene as a proxy for exposure to other carcinogenic polycyclic aromatic hydrocarbons (PAHs), t,t-muconic acid as a metabolite of benzene, 2,5-dichlorophenol (2,5-DCP), organophosphate pesticide metabolites, and di(2-ethylhexyl) phthalate (DEHP) metabolites. In blood, arsenic, polychlorinated biphenyl (PCB) congeners 118 and 156, hexachlorobenzene (HCB), dichlorodiphenyltrichloroethane (DDT) and perfluorooctanoic acid (PFOA) were analyzed. Levels of methylmercury (MeHg) were measured in hair. Multiple linear regression models were used to establish exposure-response relationships.

RESULTS

Biomarkers of exposure to PAHs and urinary chromium were associated with higher levels of both 8-OHdG in urine and DNA damage detected by the alkaline comet assay. Concentrations of 8-OHdG in urine increased in relation with increasing concentrations of urinary t,t-muconic acid, cadmium, nickel, 2,5-DCP, and DEHP metabolites. Increased concentrations of PFOA in blood were associated with higher levels of DNA damage measured by the alkaline comet assay, whereas DDT was associated in the same direction with the Fpg-modified comet assay. Inverse associations were observed between blood arsenic, hair MeHg, PCB 156 and HCB, and urinary 8-OHdG. The latter exposure biomarkers were also associated with higher fish intake. Urinary nickel and t,t-muconic acid were inversely associated with the alkaline comet assay.

CONCLUSION

This cross-sectional study found associations between current environmental exposure to (potential) human carcinogens in 14-15-year-old Flemish adolescents and short-term (oxidative) damage to DNA. Prospective follow-up will be required to investigate whether long-term effects may occur due to complex environmental exposures.

Chromium speciation in tannery effluent after alkaline precipitation: Isolation and characterization

It is difficult to completely remove Cr(III) from tannery effluent by alkaline precipitation due to the abundance of strong organic ligands. Thereby, the speciation of the residual Cr after alkaline precipitation is of crucial significance to guide the selection and design of further treatment process. For the first time, we revealed the speciation of the residual Cr with the aid of comprehensive analytical techniques. Results showed that the residual Cr(III) mostly located in two size ranges, i.e. the 13-100nm fraction and the <4nm fraction. Combined spectral analyses demonstrated Cr(III) was coordinated by carboxyl groups or hydroxyl groups in both fractions, while the complexation by nitrogen-containing groups was excluded by the total nitrogen and UPLC-MS analysis in the two fractions, respectively. Based on the comprehensive analyses, the structures of Cr(III) complexes in both fractions were proposed. Cr(III) cross-linked the carboxyl groups from polyacrylic acid chains to form the network gel structure in the 13-100nm fraction, while the complex structure of Cr(III) in the <4nm fraction was formed through hydroxyl-carboxyl chelation by masking agents such as tartrate and citrate. Although polyoxyethylene ether was abundantly present, it was responsible for the complexation of Cr(III) in neither fraction.

Toxicity and oxidative stress induced by chromium in workers exposed from different occupational settings around the globe: A review

The present review focused on the levels and toxicological status of heavy metals especially chromium (Cr) in the exposed workers from different occupational settings around the globe and in Pakistan. It was found that exposed workers from leather tanning and metal plating units showed elevated levels of Cr than the workers from other occupational settings. Cr and other heavy metals level in biological matrices of the exposed workers in different occupational settings revealed that developing countries are severely contaminated. Occupational settings from the Sialkot district, Pakistan exhibited elevated level of Cr in biological entities of the exposed workers. Review suggested that higher level of Cr exposure to the workers enhance the oxidative stress (reactive oxygen species (ROS) and hydroxyl (OH) radical generation) which may cause; cellular and molecular damage such as genotoxicity and chromosomal aberration formations, and carcinogenic effects. This review will help to understand the Cr contamination mechanisms and associated health implications in different occupational settings around the globe in general and particularly to Pakistan. This study will also assist occupational health and safety management authorities to devise or change the Cr recommended exposure limits (REL) for different occupational settings.

Evaluating levels and health risk of heavy metals in exposed workers from surgical instrument manufacturing industries of Sialkot, Pakistan

The study aimed to monitor heavy metal (chromium, Cr; cadmium, Cd; nickel, Ni; copper, Cu; lead, Pb; iron, Fe; manganese, Mn; and zinc, Zn) footprints in biological matrices (urine, whole blood, saliva, and hair), as well as in indoor industrial dust samples, and their toxic effects on oxidative stress and health risks in exposed workers. Overall, blood, urine, and saliva samples exhibited significantly higher concentrations of toxic metals in exposed workers (Cr; blood 16.30 μg/L, urine 58.15 μg/L, saliva 5.28 μg/L) than the control samples (Cr; blood 5.48 μg/L, urine 4.47 μg/L, saliva 2.46 μg/L). Indoor industrial dust samples also reported to have elevated heavy metal concentrations, as an example, Cr quantified with concentration of 299 mg/kg of dust, i.e., more than twice the level of Cr in household dust (136 mg/kg). Superoxide dismutase (SOD) level presented significant positive correlation (p ≤ 0.01) with Cr, Zn, and Cd (Cr > Zn > Cd) which is an indication of heavy metal's associated raised oxidative stress in exposed workers. Elevated average daily intake (ADI) of heavy metals resulted in cumulative hazard quotient (HQ) range of 2.97-18.88 in workers of different surgical units; this is an alarming situation of health risk implications. Principal component analysis-multiple linear regression (PCA-MLR)-based pie charts represent that polishing and cutting sections exhibited highest metal inputs to the biological and environmental matrices than other sources. Heavy metal concentrations in biological matrices and dust samples showed a significant positive correlation between Cr in dust, urine, and saliva samples. Current study will help to generate comprehensive base line data of heavy metal status in biomatrices and dust from scientifically ignored industrial sector. Our findings can play vital role for health departments and industrial environmental management system (EMS) authorities in policy making and implementation.

The effects of heavy metals and their interactions with polycyclic aromatic hydrocarbons on the oxidative stress among coke-oven workers

Heavy metals and polycyclic aromatic hydrocarbons (PAHs) are predominate toxic constituents of particulate air pollution that may be related to the increased risk of cardiopulmonary events. We aim to investigate the effects of the toxic heavy metals (arsenic, As; cadmium, Cd; chromium, Cr; nickel, Ni; and lead, Pb), and their interactions with PAHs on oxidative stress among coke-oven workers. A total of 1333 male workers were recruited in this study. We determined their urinary levels of As, Cd, Cr, Ni, Pb, twelve PAH metabolites, 8-hydroxydeoxyguanosine (8-OHdG), and 8-iso-prostaglandin-F2α (8-iso-PGF2α). Multivariate linear regression models were used to analyze the effects of these metals and their interactions with PAHs on 8-OHdG and 8-iso-PGF2α levels. It was found that only urinary As and Ni showed marginal or significant positive linear dose-dependent effects on 8-OHdG in this study population, especially among smokers (β=0.103, P=0.073 and β=0.110, P=0.002, respectively). After stratifying all participants by the quartiles of ΣOH-PAH, all five metals showed linear association with 8-OHdG in the highest quartile subgroup (Q4) of ΣOH-PAHs. However, these five urinary metals showed significantly consistent linear associations with 8-iso-PGF2α in all subjects and each stratum. Urinary ΣOH-PAHs can significant modify the effects of heavy metals on oxidative stress, while co-exposure to both high levels of ΣOH-PAHs and heavy metals render the workers with highest 8-OHdG and 8-iso-PGF2α (all P(interaction)≤0.005). This study showed evidence on the interaction effects of heavy metals and PAHs on increasing the oxidative stress, and these results warrant further investigation in more longitudinal studies.

Oxidative stress and DNA repair and detoxification gene expression in adolescents exposed to heavy metals living in the Milazzo-Valle del Mela area (Sicily, Italy)

BACKGROUND

The area of Milazzo-Valle del Mela (Sicily, Italy) is considered at high risk of environmental crisis by regional authorities.

OBJECTIVE

To measure oxidative-stress, DNA repair and detoxification genes in school children living near the industrial area and in age-matched controls.

METHODS

The parent study was a biomonitoring investigation evaluating heavy metal urine levels in 226 children aged 12-14 years, living in the high risk area, and in 29 age-matched controls living 45 km far from the industrial site. In the present study 67 exposed adolescents and 29 controls were included. Samples were analyzed for urinary 8-hydroxydeoxyguanosine (8OHdG) levels, and gene expression of OGG1 (DNA repair gene), NQO1, ST13, and MT1A (detoxifying genes).

RESULTS

Urinary cadmium was higher (p = 0.0004) in exposed [geometric mean, 0.46 µg/L; 25th-75th percentile: 0.3-0.56] than in control adolescents [geometric mean, 0.26 µg/L; 25th-75th percentile: 0.2-0.3]. Chromium was also significantly elevated in exposed [geometric mean, 1.52 µg/L; 25th-75th percentile: 1.19-1.93] compared with controls [geometric mean, 1.25 µg/L; 25th-75th percentile: 1.05-1.48; p = 0.02]. Urinary 8-OHdG concentration was greater in exposed than in controls (71.49 vs 61.87 µg/L, p = 0.02), and it was correlated with cadmium levels (r = 0.46, p < 0.0001), and with the combined exposure index (r = 0.43, p < 0.0001). Moreover, cadmium levels showed a robust correlation with OGG1 and MT1A gene expression levels (r = 0.44, p < 0.0001; r = 0.39, p < 0.0001, respectively). Finally, OGG1 and MT1A were over-expressed in adolescents from Milazzo-Valle del Mela area compared with controls (p = 0.0004; p < 0.0001, respectively).

CONCLUSIONS

Continuous exposure at relatively low concentrations of heavy metals is associated with increased oxidative DNA damage and impaired expression of DNA repair and detoxification genes in adolescents.

Metal exposure in schoolchildren and working children. A urinary biomonitoring study from Lahore, Pakistan

In order to document the exposure to trace metals among urban schoolchildren and rural working children, we measured the urinary concentrations of metals in schoolchildren from two areas of differing traffic intensity in Lahore, and in children working in carpet weaving or the brick industry outside Lahore. In a cross-sectional design, we recruited a convenience sample of 339 children aged 8-12 years (mean age 9.9 y, SD 1.4; 47% girls) from two elementary schools in Lahore - one situated in a high air pollution area (n=100) and one situated in an area with lower air pollution (n=79) - and from the carpet weaving industry (n=80) and brick industry (n=80). A spot urine sample was collected and concentrations of 20 metals and metalloids were measured by inductively coupled plasma-mass spectrometry (ICP-MS). Samples of drinking water were similarly analyzed. In general, the urinary concentrations of several toxic metals (including Cr, Mn, As, Mo, Cd, Pb, U) were higher than international reference values. Concentrations of As were especially elevated in children working in the brick making industry [geometric mean (GM) 118 μg/L], but they were also high among urban schoolchildren (GM 68 μg/L and 56 μg/L). Lead (Pb) was higher in urine from schoolchildren in the high air pollution area (GM 11 μg/L) than in those from the lower pollution area (GM 5.3 μg/L). Uranium (U) was high in both carpet weavers (GM 0.28 μg/L) and brick kiln workers (GM 0.45 μg/L). Concentrations of As, Pb, and U in drinking water corresponded well with urinary concentrations of metals. This descriptive study provides evidence for a high exposure to several toxic metals in this area of Pakistan. The concentrations of urinary As are in the order of those found in other regions of the world with high environmental exposure to As. The sources and pathways of exposure and the health significance of these findings need to be further investigated.

Associations of neonatal lead, cadmium, chromium and nickel co-exposure with DNA oxidative damage in an electronic waste recycling town

OBJECTIVE

This study aimed to evaluate the effects of toxic heavy metal co-exposure on DNA oxidative damage in neonates from a primitive e-waste recycling region, Guiyu town, China.

METHODS

Our participants included 201 pregnant women: 126 from Guiyu town and 75 from Jinping district of Shantou city, where no e-waste recycling and dismantling activities existed. Structured interview questionnaires were administered to the pregnant women and umbilical cord blood (UCB) samples were collected after delivery. The UCB concentrations of lead, cadmium, chromium, and nickel were analyzed by graphite furnace atomic absorption spectrometry (GFAAS). Levels of UCB plasma 8-hydroxydeoxyguanosine (8-OHdG, a DNA oxidative damage biomarker) were determined by enzyme-linked immunosorbent assay.

RESULTS

Our results suggested that UCB lead and cadmium concentrations in neonates of Guiyu were significantly higher than those of Jinping (lead: median 110.45 ng/mL vs. 57.31 ng/mL; cadmium: median 2.50 ng/mL vs. 0.33 ng/mL, both P<0.001). Parents' residence in Guiyu, and parents' work related to e-waste recycling were the risk factors associated with neonate's UCB lead and cadmium levels. No significant difference of UCB plasma 8-OHdG levels was found between Guiyu and the control area. After adjusting for potential confounders, cord plasma 8-OHdG concentrations (ng/mL) were positively associated with blood cadmium (β=0.126 ng/mL, 95% CI: 0.055 to 0.198 ng/mL), chromium (β=0.086 ng/mL, 95% CI: 0.014 to 0.158 ng/mL) and nickel (β=0.215 ng/mL, 95% CI: 0.113 to 0.317 ng/mL) concentrations.

CONCLUSIONS

The primitive e-waste recycling and dismantling activities may contribute to the elevated umbilical cord blood toxic heavy metal levels in neonates born in Guiyu. Exposures to cadmium, chromium and nickel were associated with increased oxidative DNA damage in neonates.

Highly sensitive detection of chromium (III) ions by resonance Rayleigh scattering enhanced by gold nanoparticles

Simple and sensitive determination of chromium (III) ions (Cr(3+)) has potential applications for detecting trace contamination in environment. Here, the assay is based on the enhancement of resonance Rayleigh scattering (RRS) by Cr(3+)-induced aggregation of citrate-capped gold nanoparticles (AuNPs). Transmission electron microscopy (TEM) and UV-vis absorption spectroscopy were employed to characterize the nanostructures and spectroscopic properties of the Cr(3+)-AuNP system. The experiment conditions, such as reaction time, pH value, salt concentration and interfering ions, were investigated. The combination of signal amplification of Cr(3+)-citrate chelation with high sensitivity of RRS technique allow a selective assay of Cr(3+) ions with a detection limit of up to 1.0 pM. The overall assay can be carried out at room temperature within only twenty minutes, making it suitable for high-throughput routine applications in environment and food samples.

Overview of environmental and occupational vanadium exposure and associated health outcomes: an article based on a presentation at the 8th International Symposium on Vanadium Chemistry, Biological Chemistry, and Toxicology, Washington DC, August 15-18, 2012

Vanadium (V) has a variety of applications that make it suitable for use in ceramic production and decoration, production of pigments for a variety of products, an accelerator for drying paint, production of aniline black dye, and as a mordant in coloring textiles. Taking advantage of its hardness, resilience, ability to form alloys, and its resistance to corrosion, V is also used in the production of tools, steel, machinery, and surgical implants. V is employed in producing photographic developers, batteries, and semi-conductors, and in catalyst-based recycling processes. As technologies have evolved, the use of V has increased in jet aircraft and space technology, as well as in manufacture of ultraviolet filter glass to prevent radiation injury. Due to these myriad uses, the potential for occupational exposure to V is ever-evident. Similarly, there is an increased risk for environmental contamination by V agents themselves or as components of by-products released into the environment. For example, the use of V in sulfuric acid production results in the release of soot and/or fly ash rich in vanadium pentoxide. Petroleum refinery, smelting, welding, and cutting of V-rich steel alloy, the cleaning and repair of oil-fired boilers, and catalysis of chemical productions are other sources of increased airborne V-bearing particles in local/distant environments. Exposure of non-workers to V is an increasing health concern. Studies have demonstrated associations between exposure to airborne V-bearing particles (as part of air pollution) and increased risks of a variety of pathologies like hypertension, dysrhythmia, systemic inflammation, hyper-coagulation, cancers, and bronchial hyper-reactivity. This paper will provide a review of the history of V usage in occupational settings, documented exposure levels, environmental levels of V associated with pollution, epidemiologic data relating V exposure(s) to adverse health outcomes, and governmental responses to protect both workers and non-workers from exposure to this metal.