Blood Arsenic Levels Research Articles

Hexavalent chromium exposure induces lung injury via activation of NLRP3 and AIM2 inflammasomes in rats

Hexavalent chromium (Cr(VI)) has been identified as a Class I human carcinogen, but its carcinogenic mechanism is currently unclear. There is still a lack of understanding of its associations with early pulmonary inflammatory damages. Inflammation is an important stage before the occurrence of tumors, and under the long-term stimulation of inflammation, it can promote the development of tumors. In this study, the aim is to explore the effect of Cr(VI) exposure on pulmonary inflammation and its relationship with the mechanism of inflammation cancer transformation. We established a Cr(VI) exposure model in SD rats using tracheal instillation of potassium dichromate solution, and collected samples at the time of cessation of exposure and 14 days after cessation of exposure. Analyzing the experimental results, it was found that the lung index increased after exposure to Cr(VI), promoting the occurrence of apoptosis in lung tissue cells and exacerbating lung tissue damage. The damage situation improved after exposure termination; Inductively coupled plasma mass (ICPRQ) spectrometer detection found that the exposed group had significantly increased levels of blood chromium, blood manganese, blood copper, blood arsenic, urine chromium, urine copper, and urine lead; After two weeks of repair, blood chromium and blood manganese levels were significantly lower than those in the same dose group of the exposure group, while blood copper levels were significantly higher than those in the same dose group of the exposure group. There was no significant difference in blood arsenic levels between the exposure group and the exposure group. Urine chromium and urine lead levels were significantly lower than those in the same dose group of the exposure group, while urine copper levels only increased. At the same time, it was found that Cr(VI) exposure caused disruption of oxidative stress levels in rat lung tissues. After 14-day exposure, Cr(VI) significantly decreased and oxidative stress levels significantly decreased. Further investigation revealed that Cr(VI) induces activation of inflammasomes NLRP3, AIM2, and their signaling pathways in lung inflammatory injuries, but this condition persists even after cessation of exposure. The study suggested that in hexavalent chromium induced lung tissue injuries in rats, NLRP3 and AIM2 inflammasomes and their signaling pathways activation. Furthermore, the characteristic of sustained activation after cessation of exposure was also indicated. These results provide new ideas and references for further elucidating the mechanisms of Cr(VI), lung inflammation and inflammation cancer transformation.

Customizable Zr-MOF nanoantidote-based multieffective arsenic detoxification and its extended low-toxic therapy

Arsenic (As) poisoning has become a global public problem threatening human health. Chelation therapy (CT) is the preferred treatment for arsenic poisoning. Nevertheless, efficient and safe arsenic removal in vivo remains a daunting challenge due to the limitations of chelators, including weak affinity, poor cell membrane penetration, and short half-life. Herein, a mercapto-functionalized and size-tunable hierarchical porous Zr-MOF (UiO-66-TC-SH) is developed, which possesses abundant arsenic chemisorption sites, effective cell uptake ability, and long half-life, thereby efficiently removing toxic arsenic in vivo. Moreover, the strong binding affinity of UiO-66-TC-SH for arsenic reduces systemic toxicity caused by off-target effects. In animal trials, UiO-66-TC-SH decreases the blood arsenic levels of acute arsenic poisoning mice to a normal value within 48 h, and the efficacy is superior to clinical drugs 2,3-dimercaptopropanesulfonic acid sodium salt (DMPS). Meanwhile, UiO-66-TC-SH also significantly mitigates the arsenic accumulation in the metabolic organs of chronic arsenic poisoning mice. Surprisingly, UiO-66-TC-SH also accelerates the metabolism of arsenic in organs of tumor-bearing mice and alleviates the side effects of arsenic drugs antitumor therapy. Statement of significanceArsenic (As) contamination has become a global problem threatening public health. The present clinical chelation therapy (CT) still has some limitations, including the weak affinity, poor cell membrane permeability and short half-life of hydrophilic chelators. Herein, a metal−organic framework (MOF)-based multieffective arsenic removal strategy in vivo is proposed for the first time. Mercapto-functionalized and size-tunable hierarchical porous Zr-MOF nanoantidote (denoted as UiO-66-TC-SH) is accordingly designed and synthesized. After injection, UiO-66-TC-SH can form Zr−O−As bonds and As−S bonds with arsenic, thus enhancing arsenic adsorption capacity, cycling stability and systemic safety simultaneously. The acute arsenic poisoning model results indicate that UiO-66-TC-SH shows superior efficacy to the clinical drug sodium dimercaptopropanesulfonate (DMPS). More meaningfully, we find that UiO-66-TC-SH also accelerates the metabolism of arsenic in organs of tumor-bearing mice and alleviates side effects of arsenic drugs anti-tumor therapy.

Associations of Heavy Metals with Cognitive Function: An Epigenome-Wide View of DNA Methylation and Mediation Analysis.

Exposure to heavy metals has been reported to be associated with impaired cognitive function, but the underlying mechanisms remain unclear. This pilot study aimed to identify key heavy metal elements associated with cognitive function and further explore the potential mediating role of metal-related DNA methylation. Blood levels of arsenic, cadmium, lead, copper, manganese, and zinc and genome-wide DNA methylations were separately detected in peripheral blood in 155 older adults. Cognitive function was evaluated using the Mini-Mental State Examination (MMSE). Least absolute shrinkage and selection operator penalized regression and Bayesian kernel machine regression were used to identify metals associated with cognitive function. An epigenome-wide association study examined the DNA methylation profile of the identified metal, and mediation analysis investigated its mediating role. The MMSE scores showed a significant decrease of 1.61 (95% confidence interval [CI]: -2.64, -0.59) with each 1 standard deviation increase in ln-transformed arsenic level; this association was significant in multiple-metal models and dominated the overall negative effect of 6 heavy metal mixture on cognitive function. Seventy-three differentially methylated positions were associated with blood arsenic (p < 1.0 × 10-5). The methylation levels at cg05226051 (annotated to TDRD3) and cg18886932 (annotated to GAL3ST3) mediated 24.8% and 25.5% of the association between blood arsenic and cognitive function, respectively (all p < 0.05). Blood arsenic levels displayed a negative association with the cognitive function of older adults. This finding shows that arsenic-related DNA methylation alterations are critical partial mediators that may serve as potential biomarkers for further mechanism-related studies. ANN NEUROL 2024;96:87-98.

Arsenic's shadowy influence: A systematic review of its carcinogenic role in gallbladder cancer.

Gallbladder carcinoma (GBC) and cholangiocarcinoma are aggressive forms of cancer developed in the gallbladder and biliary tracts which are related to the liver. This systematic review aimed to highlight the significant association between gallbladder, biliary cancers, and arsenic exposure. An extensive search was conducted in Embase, Cochrane, Scopus, PubMed, and Web of Science. We included studies that assessed arsenic levels in gallbladder cancer patients, without restrictions on age, sex, or language. Biological samples, such blood, bile, gallbladder tissue, gallstones, and hair were obtained, and arsenic levels were measured. Also, arsenic water and soil concentrations were collected. A total of 13 studies were included in our review. These studies included 2234 non-gallbladder carcinoma patients and 22 585 gallbladder carcinoma cases. The participant demographics showed a gender distribution of 862 males and 1845 females, with an age range of 20-75 years. The average body mass index (BMI) was 19.8 kg/m2 for nongallbladder carcinoma patients and 20.1 kg/m2 for gallbladder carcinoma cases. The selected studies examined arsenic concentrations across various biological samples, including blood, hair, gallstones, and bile. Blood arsenic levels ranged from 0.0002 to 0.3893 μg/g and were significantly associated with increased gallbladder carcinoma risk in several studies. Hair also demonstrated a significant correlation, with arsenic concentrations ranging from 0.0002 to 6.9801 μg/g. There is a strong link between arsenic exposure and gallbladder cancer or cholangiocarcinoma. Even chronic exposure to low-moderate amounts could lead to gallbladder carcinoma. These findings stress the need for more comprehensive and dedicated studies, to control arsenic water/soil levels and seek other preventive measures for this high mortality disease.

Association of exposure to multiple heavy metals during pregnancy with the risk of gestational diabetes mellitus and insulin secretion phase after glucose stimulation

Association of exposure to multiple heavy metals during pregnancy with the risk of gestational diabetes mellitus and insulin secretion phase after glucose stimulation

Basit Febril Nöbetli Çocuklarda Civa, Kadmiyum, Arsenik Düzeyleri ve Nöbet Süresi ile İlişkilerinin Belirlenmesi

Objective: Heavy metals may cause neuronal damage by inducing oxidative stress. This study aims to investigate the levels of mercury, cadmium, and arsenic in children with febrile seizures and their correlation with seizure duration. Materials and Methods: The study was conducted on 40 children who experienced simple febrile seizures and 30 children who had a fever but did not experience seizures. The study analyzed complete blood count, serum high-sensitive C-reactive protein, albumin, whole blood mercury, cadmium, and arsenic levels. The analysis was conducted six hours after the seizure for those who experienced seizures and six hours after the onset of fever for those who did not experience seizures. Results: Our study found that the patient group had significantly higher levels of arsenic in their blood compared to the control group. At the same time, there was no significant difference in the levels of mercury and cadmium. However, we could not establish any relationship between the seizure duration and the heavy metals levels. Conclusion: While mercury and cadmium levels are normal in children with simple febrile seizures, arsenic levels are high. However, the levels of all three heavy metals have no relationship with the duration of seizures.

Blood lead concentrations in exposed forecourt attendants and taxi drivers in parts of South Africa

BackgroundLeaded fuel was banned in South Africa in 2006, in order to improve human health and reduce environmental pollution. Lead (Pb) has been suggested to contribute to the development of neurodegenerative disorders, and the role of respiratory exposure to Pb from petrol fumes should not be neglected in this context. In addition to Pb, petrol contains various harmful chemicals including other neurotoxic metals and hydrocarbons. Objectives and MethodsHere, we investigated concentrations of Pb and other metals in blood from petrol station forecourt attendants (n = 38), taxi drivers (n = 21), and unexposed controls (n = 36). Taxi drivers and forecourt attendants were divided into three groups each, based on number of years worked. A questionnaire was designed to investigate the health status of the participants. Blood samples were collected by medical professionals and analyzed for metal concentrations by ICP-MS. ResultsA positive correlation between number of years worked and Pb blood concentrations was found. The highest Pb concentration (60.2 µg/L) was observed in a forecourt attendant who had worked 11–20 years, and the average Pb concentration in this group (24.5 µg/L) was significantly (p < 0.05) higher than in forecourt attendants who had worked 2–5 years (10.4 µg/L). Some individuals had elevated concentrations of manganese, arsenic, cadmium, chromium and cobalt, yet not significantly elevated at the group level. The blood levels of arsenic appeared to be related to smoking. Mood swings, dizziness, headaches and tiredness were reported by the workers. ConclusionBlood Pb concentrations in petrol station forecourt attendants and taxi drivers exposed to leaded petrol are elevated and correlate to exposure time. A health monitoring program should be erected for all individuals working in these industries, and preventive measures should be implemented to eliminate metal exposure from petrol.

Heavy metal levels in the dairy production chain in China

AbstractThe aims of this study were to investigate the heavy metal pollution status and distribution and to analyze the relationships among metal concentrations of different links in the dairy production chain. Chromium (Cr), arsenic (As), cadmium (Cd), lead (Pb), copper (Cu), and zinc (Zn) levels in water, fodder, milk, blood, hair, and feces samples collected from cows from five dairy farms in China were measured. The concentrations of Cr, As, Cd, Pb, Cu, and Zn were 4.61–11.11, 0.06–0.46, 0.17–0.29, 2.84–4.23, 4.11–7.72, and 7.23–19.91 mg/kg in silage; 12.72–40.85, 0.76–2.40, 0.05–0.16, 4.73–9.16, 44.14–78.46, and 4148.51–4845.20 μg/L in milk; 33.59–60.73, 0.09–3.57, 0.29–1.78, 20.14–39.20, 821.34–1007.45, and 2665.10–4929.95 μg/L in blood; 0.59–1.06, 0.02–0.09, 0.08–0.11, 1.70–2.09, 6.45–8.64, and 9.73–1.56 mg/kg in hair; 31.75–296.35, 0.33–5.96, 0.18–0.53, 3.35–9.06, 12.27–41.39, and 56.54–196.34 mg/kg in feces, respectively. The concentrations of heavy metals in hair were higher than those in the other samples and when combined with the results from the silage and tissue samples, we can assume that cow's hair can be used as a biological indicator for heavy metal contamination in the dairy production chain.

Some metals and metalloids in the blood of three species of shorebirds increase while foraging during two-week migratory stopover in Delaware Bay, New Jersey

Most migratory shorebird species are declining, some are endangered, and some may be vulnerable to contaminants on long distance travel between wintering grounds and high latitude breeding grounds. We examined whether shorebirds accumulated trace elements at the Delaware Bay (New Jersey) stopover by testing the null hypothesis that there was no difference in the levels of arsenic, cadmium, chromium, lead, mercury, and selenium in blood of three species of shorebirds collected early in their stopover compared to levels in blood collected about two weeks later near the end of the stopover, before departing for breeding grounds. There were significantly higher levels of all metals and metalloids in the blood of ruddy turnstone (Arenaria interpres) later in May than earlier. There were seasonal increases in blood levels of arsenic and selenium for all three species. Chromium and lead levels also increased in red knots (Calidris canutus). These increases occurred although the birds were only present for about two weeks. Levels of arsenic, mercury, and lead in knots and selenium in sanderlings (Calidrris alba), exceeded reported effects levels. These results have potential implications for studying the refueling physiology, energetics, and feeding behavior of migratory shorebirds. However, they also suggest cause for concern because the increased contaminant loads occur in a short period, and the high metal level bolus received all in a few days may result in adverse effects.

Elevated arsenic level in fasting serum via ingestion of fish meat increased the risk of hypertension in humans and mice.

There has been a shortage of human studies to elucidate the association between serum arsenic levels and the prevalence of hypertension. This study multidirectionally investigated associations among arsenic exposure, dietary ingestion, and the risk of hypertension by combined human epidemiological and mouse experimental studies. This study focused on the total arsenic level in fasting serum, a biomarker of arsenic exposure. Associations among ingestion frequencies of 54 diet items of Japanese food separated into six categories, total arsenic level in fasting serum, and the prevalence of hypertension were investigated in 2709 general people in Japan. Logistic regression analysis demonstrated a dose-dependent association between serum arsenic level and hypertension and a positive association between the ingestion of fish meat and hypertension. Further analysis showed that the latter association was fully mediated by increased fasting serum arsenic levels in humans. Similarly, oral exposure to the putative human-equivalent dose of arsenic species mixture with the same ratios in a common fish meat in Japan increased systolic blood pressure and arsenic levels in fasting serum in mice. This interdisciplinary approach suggests that fish-meat ingestion is a potential risk factor for arsenic-mediated hypertension. Because the increased consumption of fish meat is a recent global trend, health risks of the increased ingestion of arsenic via fish meat should be further investigated.

Relations between personal exposure to elevated concentrations of arsenic in water and soil and blood arsenic levels amongst people living in rural areas in Limpopo, South Africa

Exposure to arsenic even at low levels can lead to adverse health outcomes, however, there is a paucity of research from South Africa in relation to human exposure to arsenic. We investigated long-term exposure of residents in Limpopo province, South Africa, in a cross-sectional study by analysing water, soil and blood arsenic concentrations from two arsenic-exposed (high and medium–low exposure) villages and one non-exposed (control) village. There were statistically significant differences in the distribution of arsenic in water, soil and blood amongst the three sites. The median drinking water arsenic concentration in the high-exposure village was 1.75 µg/L (range = 0.02 to 81.30 µg/L), 0.45 µg/L (range = 0.100 to 6.00 µg/L) in the medium- / low-exposure village and 0.15 µg/L (range = < limit of detection (LOD) to 29.30 µg/L) in the control site. The median soil arsenic concentration in the high-exposure village was 23.91 mg/kg (range = < LOD to 92.10 mg/kg) whilst arsenic concentrations were below the limit of detection in all soil samples collected from the medium-/low-exposure and control villages. In the high-exposure village, the median blood arsenic concentration was 1.6 µg/L (range = 0.7 to 4.2 µg/L); 0.90 µg/L (range = < LOD to 2.5 µg/L) in the medium-/low-exposure village and 0.6 µg/L (range = < LOD to 3.3 µg/L) in the control village. Significant percentages of drinking water, soil and blood samples from the exposed sites were above the internationally recommended guidelines (namely, 10 µg/L, 20 mg/kg and 1 µg/L, respectively). Majority of participants (86%) relied on borehole water for drinking and there was a significant positive correlation between arsenic in blood and borehole water (p-value = 0.031). There was also a statistically significant correlation between arsenic concentrations in participants’ blood and soil samples collected from gardens (p-value = 0.051). Univariate quantile regression found that blood arsenic concentrations increased by 0.034 µg/L (95% CI = 0.02–0.05) for each one unit increase in water arsenic concentrations (p < 0.001). After adjusting for age, water source and homegrown vegetable consumption in multivariate quantile regression, participants from the high-exposure site had significantly higher blood concentrations than those in the control site (coefficient: 1.00; 95% CI = 0.25–1.74; p-value = 0.009) demonstrating that blood arsenic is a good biomarker of arsenic exposure. Our findings also provide new evidence for South Africa on the association between drinking water and arsenic exposure, emphasising the need for the provision of potable water for human consumption in areas with high environmental arsenic concentrations.

Association between heavy metals exposure and infertility among American women aged 20-44 years: A cross-sectional analysis from 2013 to 2018 NHANES data.

Infertility has been confirmed as a significant medical and social problem. Heavy metal exposure refers to a risk factor for infertility, which is capable of damaging the reproductive system of males and females. However, heavy metal exposure and female infertility have rarely been investigated. The aim of this study was to analyze the association between heavy metal exposure and female infertility. A cross-sectional study using data from three cycles of the National Health and Nutrition Examination Survey (NHANES, 2013-2018) was performed. Female infertility was evaluated by positive responses to question rhq074 in the questionnaire. Cadmium (Cd), lead (Pb), mercury (Hg), and arsenic (As) levels in blood or urine were examined by inductively coupled plasma mass spectrometry. The correlation between heavy metal and female infertility was analyzed through weighted logistic regression. A total of 838 American women aged 20-44 years were covered in the study. Among all participants, 112 (13.37%) women were subjected to infertility. Urinary Cd and urinary As levels were significantly higher in infertile women than in control women (P < 0.05, P < 0.05). Urinary As showed a positive correlation with the prevalence of female infertility, and the risk of infertility rose with the increase of urinary As levels (P for trend = 0.045). Urinary Cd was associated with female infertility in some weighted logistic regression (Crude, Q2: OR = 3.99, 95% CI 1.82, 8.74, Q3: OR = 2.90, 95% CI 1.42, 5.92. Model 1, Q2: OR = 3.68, 95% CI 1.64, 8.27, Q3: OR = 2.33, 95% CI 1.13, 4.48. Model 2, Q2: OR = 4.11, 95% CI 1.63, 10.07, Q3: OR = 2.44, 95% CI 1.07, 5.53. Model 3, Q2: OR = 3.77, 95% CI 1.52, 9.35). Moreover, blood Pb (OR = 1.52, 95% CI 1.07, 2.16), urinary Pb (OR = 1.68, 95% CI 1.11, 2.55), and urinary As (OR = 1.02, 95% CI 1.00, 1.03) were positively correlated with the risk of infertility in women aged 35-44 years. The blood Pb (OR = 1.67, 95% CI 1.16, 2.40, 2.49) and urinary Pb (OR = 1.54, 95% CI 1.00, 2.38) in women with BMI ≥25 were positively correlated with the risk of infertility. Urinary As was significantly associated with female infertility, and the risk of infertility increased with higher urinary As levels. To some extent, urinary Cd was correlated with infertility. Blood/urine Pb was related to infertility in advanced age and overweight/obese women. The results of this study need to be further validated in future prospective studies.

Association between the concentrations of some toxic metals and the risk of uterine fibroids among Nigerian women

Background: Uterine fibroids are a major health challenge to some women in the world, especially women of African descendants. The etiology of uterine fibroids and the mechanisms of their growth are not fully understood, and those factors that make women to be susceptible to fibroid development are subjects of investigation. Environmental toxicants such as toxic metals exposure have been implicated, but the results have not been consistent. This study seeks to determine the association between blood cadmium (Cd), arsenic (As), and lead (Pb) levels and the risk of uterine fibroids among women of reproductive age. Materials and Methods: This case–control study comprised 100 women of reproductive age (age range, 20–50 years) with uterine fibroid and 50 age-matched women without uterine fibroids. Fibroids were diagnosed using abdominal scan by attending physicians. Furthermore, the control subjects were screened for fibroids using abnormal scan. Blood Cd, As, and Pb were determined using an atomic absorption spectrophotometer, and the risk of association was calculated. Results: The mean blood Cd, As, and Pb were significantly higher (P &lt; 0.001) among women with fibroid than those without fibroid (controls). The odds ratio for Cd 2.62 (confidence interval [CI]: 0.02–0.05), As 1.02 (CI: 0.02–0.030), and Pb 1.42 (CI: 0.04–0.129) was greater among women with uterine fibroids than controls. Conclusions: Exposure to cadmium and lead might be a risk factor for developing uterine fibroids among Nigerian women.

Metal mixture mediates associations between socioeconomic indicators and blood pressure outcomes in rural Bangladeshi adults: Evidence from a prospective population study

BACKGROUND AND AIM: There is limited evidence on the causal mechanism in the socioeconomic differentials in blood pressure (BP) in low and middle-income countries (LMICs). We, therefore, examined the associations of socioeconomic indicators (SEIs) and BP, socioeconomic disparities in metal mixture exposures, and the potential mediation effect of metal mixtures in the associations between SEIs and BP outcomes in rural Bangladeshi adults. METHODS: This study included 900 rural Bangladeshi adults prospectively followed for six years in the Bangladesh vitamin E and selenium Trial (BEST). Blood pressure was measured at baseline and during three biennial follow-up examinations. Blood levels of arsenic, lead, selenium, and urinary arsenic, including socioeconomic indicators-years of education, and agricultural land ownership (ALO), were measured at baseline. Weighted quantile sum (WQS) regression was used to estimate the joint effects of metal mixture on systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse pressure (PP), and mean arterial pressure (MAP) taken at the third follow-up. Causal mediation effect of the metal mixture was estimated using the parametric g-computation method. RESULTS: Education was positively, but ALO was inversely associated with BP. Participants with higher SEIs were less likely to be exposed to metal mixtures than their counterparts. Metal mixture mediated the associations of SEIs with SBP, DBP, MAP, and PP. For example, the randomized analogue of total natural direct effect (rRTNDE) was 5.31 (95% CI: 1.91, 8.77) and the pure natural indirect effect (rRPNIE) was -0.67 (95% CI: -1.34, -0.22) for education and SBP. Similarly, the rRTNDE was -2.31 (95% CI: -4.37, -0.33) and the rRPNIE was -0.29 (95% CI: -0.70, -0.03) for ALO and SBP. There was no evidence of the exposure-mediator interaction in the mediation models (Pint&amp;#x3e;0.20). CONCLUSIONS: Our study suggests that metal mixture mediates socioeconomic differentials in BP. KEYWORDS: Blood Pressure; Metals; SES; Mediation; Mixture

Влияние генетического полиморфизма генов GSTM1, GSTT1 и GSTP1 на содержание металлов в крови у плавильщиков производства сплавов цветных металлов

Heavy metal ions are known to induce generation of a large number of reactive oxygen species (ROS). Glutathione S-transferases (GSTs) play an important role in adaptation and response to oxidative stress. GSTM1, GSTT1, and GSTP1 genes have numerous described polymorphisms, the most significant being GSTM1, GSTT1, and GSTP1 Ile105Val deletion ones. Our objective was to study the relationship between the genetic polymorphism of GSTM1, GSTT1, GSTP1 genes and blood levels of metals in smelter operators engaged in crude lead refining. We examined 55 male lead-refining furnace operators working at a non-ferrous metal alloy plant. Blood metal concentrations were measured by inductively coupled plasma mass spectrometry. GSTM1 and GSTT1 deletion polymorphisms were determined using real-time SYBR Green qPCR and that of GSTP1 Ile105Val – using a commercial SNP Screening Kit. Statistical data processing was carried out using the Mann – Whitney U-test. Blood levels of industry-specific metals were not statistically different between the workers with GSTT1 and GSTP1 genotypes. We established, however, that men with the null genotype of GSTM1 had significantly higher blood arsenic levels. Our findings indicate that a high blood arsenic level associated with occupational exposure may be attributed to the GSTM1 null genotype. This observation can be used to identify the most vulnerable groups of individuals at risk of overexposure to arsenic.

Effects of genetic polymorphisms of GSTM1, GSTT1, and GSTP1 genes on blood metal levels in non-ferrous metal alloy smelter operators

Heavy metal ions are known to induce generation of a large number of reactive oxygen species (ROS). Glutathione S-transferases (GSTs) play an important role in adaptation and response to oxidative stress. GSTM1, GSTT1, and GSTP1 genes have numerous described polymorphisms, the most significant being GSTM1, GSTT1, and GSTP1 Ile105Val deletion ones. Our objective was to study the relationship between the genetic polymorphism of GSTM1, GSTT1, GSTP1 genes and blood levels of metals in smelter operators engaged in crude lead refining. We examined 55 male lead-refining furnace operators working at a non-ferrous metal alloy plant. Blood metal concentrations were measured by inductively coupled plasma mass spectrometry. GSTM1 and GSTT1 deletion polymorphisms were determined using real-time SYBR Green qPCR and that of GSTP1 Ile105Val – using a commercial SNP Screening Kit. Statistical data processing was carried out using the Mann – Whitney U-test. Blood levels of industry-specific metals were not statistically different between the workers with GSTT1 and GSTP1 genotypes. We established, however, that men with the null genotype of GSTM1 had significantly higher blood arsenic levels. Our findings indicate that a high blood arsenic level associated with occupational exposure may be attributed to the GSTM1 null genotype. This observation can be used to identify the most vulnerable groups of individuals at risk of overexposure to arsenic.

A Systematic Review on Environmental Factors associated with Autism Spectrum Disorder in Bangladesh

Objective: Exposure to different environmental factors appears to be widespread, detrimental to human brain development and a potential risk factor for autism spectrum disorder (ASD). We conducted a systematic review on the relationship between environmental factors and ASD in Bangladesh.Methods: This paper reviews the evidence on modifiable environmental factors that have been associated, in some studies, with ASD, including socio-demographic and physical environmental factors exposures during prenatal and postnatal periods. Besides, this review is restricted to human studies with at least 50 cases of ASD, having a valid comparison group, conducted within the past two decades. Moreover, literatures searched using three electronic databases (PubMed, Google Scholar, and Biomed Central) from August 2020 to January 2021, based on the PRISMA guidelines. Literatures screened by two distinguished reviewers (Khan MS; Tareq SM), and resolved differences by consensus and further discussion with third reviewer based on requirements. Then selected the eligible 21 studies based on inclusion criteria’s. Two of the reviewers independently screened articles, extracted data for descriptive information and assessed risk of bias by using the Newcastle-Ottawa scale (NOS).Results: There is no article found with poor quality in NOS. The overall quality of the studies is high. There are strong association between ASD risk and some factors such as advanced maternal age, lead exposure during pregnancy and early childhood, blood Arsenic level of ASD children. Though few factors are related to increased risk of ASD; so far, no specific environmental factor has been found associated with increased risk of ASD with large power of study.Conclusion: There is appears to be a lack of such type of study in developing countries like Bangladesh. Therefore, nationwide widespread research needed to address the modifiable environmental risk factors for ASD.International Journal of Human and Health Sciences Vol. 06 No. 03 July’22 Page: 237-248

Association and mediation analyses among multiple metals exposure, plasma folate, and community-based impaired estimated glomerular filtration rate in central Taiwan

BackgroundChronic kidney disease (CKD) is increasing, with heavy metal exposure an important risk factor. Additionally, the antioxidant folic acid has been studied for reducing blood arsenic levels and related tissue damage. Therefore, we explored the association and mediation effects among various heavy metal levels in blood, plasma folate, other CKD risk factors, and impaired estimated glomerular filtration rate (eGFR).MethodsWe constructed a community-based cross-sectional study from the Human Biomonitoring and Environmental Health Program in central Taiwan. A total of 1643 participants had lived locally for > 5 years, > 40 years old, and completely received health examinations and biospecimen collections. Impaired eGFR was defined as one single eGFR < 60 mL/min/1.73 m2. Plasma folate and metal levels in blood were determined, as well as urinary 8-hydroxy-2′-deoxyguanosine as an oxidative stress marker. Generalized weighted quantile sum (WQS) regression analysis was used to calculate a WQS score, reflecting overall body-burden of multiple metals (arsenic, cadmium, chromium, nickel, and lead) in blood.ResultsImpaired eGFR was identified in 225 participants. Participants with high WQS scores had increased risk of impaired eGFR (odds ratio = 1.67; 95% confidence interval [CI]: 1.34, 2.07). Of five metals, arsenic, lead, and cadmium were weighted highly in impaired eGFR. Participants with high WQS and folate insufficiency (< 6 ng/mL) had 2.38-fold risk of impaired eGFR compared to those with low WQS and high folate (≥6 ng/mL) (95% CI: 1.55, 5.17). Similar increased 4.16-fold risk of impaired eGFR was shown in participants with high WQS and uric acid levels (95% CI: 2.63, 6.58). However, there were no significant WQS–folate (p = 0.87) or WQS–uric acid (p = 0.38) interactions on impaired eGFR risk. As a mediator, uric acid contributed 24% of the association between WQS score and impaired eGFR risk (p < 0.0001). However, no mediation effect of plasma folate was observed.ConclusionWQS analysis could be applied to evaluate the joint effects of multiple metals exposure. High WQS scores may influence impaired eGFR risk through increased uric acid levels. A large-scale and prospective cohort study is necessary to validate these results and demonstrate any causal relationship.

Exposure to multiple toxic metals and the risk of early embryonic arrest among women undergoing assisted reproductive techniques

BackgroundEarly embryonic arrest is a great challenge for in vitro fertilization. Whether exposure to toxic metals is associated with an increased risk of early embryonic arrest warrants investigation. ObjectivesHere, we conducted a case-control study in infertile women to estimate the associations between blood barium (Ba), arsenic (As), mercury (Hg), and lead (Pb) exposure levels and the risk of early embryonic arrest. MethodsBa, As, Hg, and Pb exposure levels in fasting blood collected from 74 infertile women (123 cycles) with early embryonic arrest and 157 infertile women (180 cycles) without early embryonic arrest were measured by ICP–MS. Bayesian kernel machine regression (BKMR) was used to assess the association of exposure level of toxic metals mixture with the risk of early embryonic arrest as well as to evaluate which metal playing a leading role in the association, and then generalized estimating equations (GEEs) were used to evaluate the relationship between the selected harmful metal and the risk of early embryonic arrest. Finally, the potential causes of early embryonic arrest originating from the harmful metal exposure were explored. ResultsBlood Ba levels were significantly higher in the case group than that in the control group (p = 0.009) rather than As, Pb and Hg. Results from BKMR showed that exposure to toxic metals mixture increased the risk of early embryonic arrest, with Ba playing a leading role (PIP = 0.9612). GEE analysis showed that high Ba exposure level was related with the increased risk of early embryonic arrest (p < 0.05) and it impacted on the oogenesis significantly. ConclusionsOur study found that exposure to toxic metals mixture was associated with the increased risk of early embryonic arrest, and Ba contributed most to the increased risk. Higher Ba exposure in whole blood corresponds to a higher risk of early embryonic arrest and impacted on the oogenesis significantly.

Effect of exposures to mixtures of lead and various metals on hypertension, pre-hypertension, and blood pressure: A cross-sectional study from the China National Human Biomonitoring

We aimed to explore the effects of mixtures of lead and various metals on blood pressure (BP) and the odds of pre-hypertension (systolic blood pressure (SBP) 120–139 mmHg, and/or diastolic blood pressure (DBP) 80–89 mmHg) and hypertension (SBP/DBP ≥140/90 mmHg) among Chinese adults in a cross-sectional study. This study included 11,037 adults aged 18 years or older from the 2017–2018 China National Human Biomonitoring. Average BP and 13 metals (lead, antimony, arsenic, cadmium, mercury, thallium, chromium, cobalt, molybdenum, manganese, nickel, selenium, and tin) in blood and urine were measured and lifestyle and demographic data were collected. Weighted multiple linear regressions were used to estimate associations of metals with BP in both single and multiple metal models. Weighted quantile sum (WQS) regression was performed to assess the relationship between metal mixture levels and BP. In the single metal model, after adjusting for potential confounding factors, the blood lead levels in the highest quartile were associated with the greater odds of both pre-hypertension (odds ratio (OR): 1.56, 95% CI: 1.22–1.99) and hypertension (OR:1.75, 95% CI: 1.28–2.40) when compared with the lowest quartile. We also found that blood arsenic levels were associated with increased odds of pre-hypertension (OR:1.31, 95% CI:1.00–1.74), while urinary molybdenum levels were associated with lower odds of hypertension (OR:0.68, 95% CI:0.50–0.93). No significant associations were found for the other 10 metals. WQS regression analysis showed that metal mixture levels in blood were significantly associated with higher SBP (β = 1.56, P < 0.05) and DBP (β = 1.56, P < 0.05), with the largest contributor being lead (49.9% and 66.8%, respectively). The finding suggests that exposure to mixtures of metals as measured in blood were positively associated with BP, and that lead exposure may play a critical role in hypertension development.