Assessement of Blood Lead and Cadmium Levels in Occupationally Exposed Workers of Jodhpur, Rajasthan

Assessment of heavy metals among auto workers in metropolitan city: a case study

In recent decades, heavy metals (HMs) have emerged as a global health concern. Unfortunately, in Pakistan, there is a general lack of awareness regarding the potential health risks associated with HMs pollution among automobile workers. Herein, we investigated the concentration of heavy metals such as lead (Pb), cadmium (Cd), and chromium (Cr) among automobile workers who were occupationally exposed in Mingora City, Khyber Pakhtunkhwa, Pakistan. Three different automobile groups, i.e., battery recyclers, spray painters, and mechanics were studied in detail. A total of 40 blood samples were collected from automobile workers groups while 10 blood samples were collected as control individuals from different locations in the study area. We investigated heavy metals concentration with a standard method using an atomic absorption spectrometer AAS (PerkinElmer Analyst 700, United States). Based on our findings, the battery recycling group displayed the most elevated Pb levels (5.45 ± 2.11 μg/dL), exceeding those of both the spray painters' group (5.12 ± 1.98 μg/dL) and the mechanics' group (3.79 ± 2.21 μg/dL). This can be attributed to their higher exposure to Pb pollution resulting from the deterioration, dismantling, grinding, or crushing of old batteries. In the context of chromium (Cr) exposure, a similar trend was observed among the battery recycling group, as well as the spray painters and mechanics groups. However, in the case of cadmium (Cd), the mechanics' group exhibited the highest level of exposure (4.45 ± 0.65 μg/dL), surpassing the battery recycling group (1.17 ± 0.45 μg/dL) and the spray painters' group (1.35 ± 0.69 μg/dL), which was attributed to their greater exposure to welding fumes and other activities in their workplace. We believe that our findings will encourage regulatory measures to improve the health of automobile workers. However, further work is needed to determine various health-related issues associated with heavy metal exposure among automobile workers.

Assessment of Blood Lead Level of School Children in 10 Cities of India: A Cross-Sectional Study

OBJECTIVES

To assess the blood lead level (BLL) of school children in 10 cities of India.

METHODS

This multi-centric cross-sectional study enrolled participants from randomly selected schools. Data on demographic details, socioeconomic status (SES) and anthropometric indicators was collected. Samples were collected for assessment of lead level in blood. Inductively coupled plasma-optical emission spectrometry technique was used to assess BLL.

RESULTS

From April 2019 through February 2020, 2247 participants were recruited from sixty schools (62.6% government schools) with equal gender distribution. The overall median (interquartile range) BLL was 8.8 (4.8, 16.4) µg/dl. The highest median (interquartile range) BLL was in Manipal 30.6 (23.0, 46.7) and lowest in Dibrugarh 4.8 (3.2, 7.0). Overall, 82.5% of participants had BLL above ≤4 µg/dl. Significant negative correlation was observed between BLL and SES (correlation= -0.24, p <0.001), anthropometric indicators (correlation= -0.11, p <0.001), hemoglobin level (correlation= -0.045, p = 0.03) and multivariate regression model showed association with gender, SES and anthropometric indicators.

CONCLUSIONS

BLL are elevated in urban school going children and there is intercity variation. Hence, urgent focus is needed to reduce exposure to lead in India.

Investigation of imbalances in essential/toxic metal levels in the blood of laryngeal cancer patients in comparison with controls

Laryngeal carcinoma is one of the common types of head and neck cancer, with men being more likely than women to develop it. Diet, age, gender, smoking habits, and environmental factors play important roles in its development. The goal of this study was to ascertain if there were imbalances in essential and toxic trace metals owing to the initiation and progression of laryngeal cancer. Atomic absorption spectrometry was employed to quantify selected macroelements, and essential/toxic trace metals in blood of the cancerous patients and matching controls. Significantly higher concentrations of Pb, Cu, Fe, and Sr while substantially lower levels of Na, K, Ca, and Mg were observed in the cancer patients compared with the controls. Considerably disparate mutual relationships among the macroelements, and essential/toxic trace metals in the patients and controls were manifested by their correlation coefficients. Similarly, multivariate apportionment of the metal levels showed appreciably diverse associations and grouping in the patients and controls. The laryngeal cancer patients exhibited significant disparities in the metal levels among various sub-types (supraglottic, subglottic, transglottic, and glottic cancer) and stages (I, II, III, and IV) of the disease. Most of the metals revealed distinct differences based on the gender, habitat, age, eating preferences, and smoking habits in both donor groups. Overall, the study demonstrated significant imbalances among the macroelements, and essential/toxic trace metal levels in the blood of laryngeal cancer patients compared to the controls.

Plasma microRNA expression and immunoregulatory cytokines in an Indian population occupationally exposed to cadmium

Following its accumulation in the body, cadmium (Cd) exposure is associated with devastating effects on multiple organ system of the human body. The immune system is one of the sensitive targets for Cd-induced toxicity. Recently, studies have demonstrated a significant role of Cd in inducing epigenetic alterations. With this background, the present study was planned to study the changes in candidate microRNA (miRNA) expression associated with immune regulation in occupationally Cd-exposed workers. One hundred individuals involved in welding and metal handicraft manufacturing, while 80 apparently healthy subjects without any prior history of occupational exposure were recruited for the study. Blood Cd level was determined by atomic absorption spectrometry. Serum cytokine levels were measured using an enzyme-linked immunosorbent assay and serum miRNA expression of candidate miRNAs (miR-146a, miR-210, and miR-222) were determined by real-time polymerase chain reaction. The median Cd level (2.40 μg/L) in the occupationally exposed workers was significantly higher than the nonexposed subjects (0.90 μg/L). Among the cytokines, interleukin-4 (IL-4), and tumor necrosis factor-alpha (TNF-α) were significantly higher while IL-2 and IL-10 were significantly lower in the exposed. The expression level of miR-146a and miR-222 were significantly different between the groups with the former showing downregulation and later showing upregulation. Correlation analysis revealed a positive and negative association of miR-222 and miR-146a with blood cadmium level, IL-17 as well as TNF-α, respectively. Furthermore, the in-silico analysis revealed a significant role of the studied miRNAs in various cellular and genetic pathways. The findings of the present study demonstrate significant involvement of Cd-induced alteration in miRNAs in varied immune regulatory changes in exposed individuals.

Cadmium chloride generates cytotoxic reactive species that cause oxidative damage and morphological changes in human erythrocytes

Cadmium chloride (CdCl₂₎ is a widely used industrial compound that exhibits multiple organ toxicity. Cadmium is transported through blood where erythrocytes are exposed to its action. Here the effect of CdCl₂ on human erythrocytes was examined under in vitro conditions. Human erythrocytes were treated with 0.01-0.5 mM CdCl₂ for 24 h at 37 °C. Lysates were made from CdCl₂ treated and untreated (control) cells and used for further analysis. CdCl₂ treatment resulted in marked hemolysis of erythrocytes and oxidation of hemoglobin to methemoglobin. This will result in anemia and also reduce the oxygen carrying ability of erythrocytes. Hemoglobin oxidation was accompanied by degradation of heme and release of free ferrous iron moiety. Further analysis showed elevated lipid hydroperoxides and formation of advanced oxidation protein products along with reduction in total sulfhydryl content, indicating the generation of oxidative stress condition in the cell. Incubation of erythrocytes with CdCl₂ enhanced generation of reactive oxygen and nitrogen species, decreased the antioxidant power and inhibited pathways of glucose metabolism. Plasma membrane was damaged as indicated by enhanced osmotic fragility and inhibition of membrane bound enzymes. This was confirmed by electron microscopy which showed formation of echinocytes. These results show that CdCl₂ generates reactive species which impair the antioxidant system resulting in oxidative damage to erythrocytes.

Cadmium Accumulation in the Goat Liver and Kidney Is Partially Promoted by the Upregulation of Metal Transporter Genes

Metal transporters, including divalent metal-ion transporter-1 (DMT1), Zrt-/Irt-like protein 8 and 14 (ZIP8 and ZIP14), and ferroportin-1 (FPN1), reportedly participate in cellular cadmium (Cd) uptake, but those in farm animals remain unclarified. This study aimed to examine the growth, plasma biochemical indices, Cd accumulation, and expression of metal transporter genes in the liver, kidney, and muscle of goats exposed to rice paddies contaminated with different levels of Cd. Twenty-four goats were randomly assigned across three dietary treatments: 0.23, 0.63, and 1.07 mg of Cd/kg of dry matter (DM) for 60 days. The results showed that dietary Cd exposure increased (p < 0.05) both Cd accumulation and the mRNA expressions of metal transporter genes (DMT1, ZIP, and FPN1) in the liver and kidney but not in the muscle, suggesting dietary Cd exhibited different deposition rates between goat liver, kidney, and muscle. These outcomes suggest that high levels of dietary Cd stimulated the expression of metal transporter genes and thereby enhanced the uptake and accumulation of Cd in the goat liver and kidney. As such, higher Cd concentrations in the liver and kidney observed with Cd diets could be partly explained by upregulation of metal transport genes expression.

Association of blood lead levels with neurobehavior and BDNF expression in school going children

BACKGROUND

Childhood Lead (Pb) toxicity has been an ongoing concern for decades; however, its underlying pathogenesis remains unclear. Although its prevalence has come down in developed countries (USA, Europe); it is relatively high in low to middle-income countries of South-East Asia. The current study aimed to evaluate the association of blood lead levels (BLLs) with neurobehavioral alterations and changes in Brain-Derived Neurotropic Factor (BDNF) expression in Indian school children.

METHODOLOGY

School going children in age group of 9-15 years (N = 72) were included in the study. Neurobehavioral changes were assessed using Childhood Psychopathological Measurement Schedule (CPMS) and BLL were measured by Graphite Furnace Atomic Absorption Spectrophotometry (GFAAS). BDNF mRNA expression and serum BDNF levels were assessed by Real-Time PCR and ELISA, respectively.

RESULTS

Median BLL was 4.95 μg/dL (IQR = 4.47), very close to the recommended toxic cut off levels (<5 μg/dL). BLLs had a direct correlation with both CPMS scores and BDNF expression. Depression was found to be significantly higher in boys than in girls with high BLLs. BDNF mRNA expression and serum BDNF levels were higher among children with high BLL, although not to significant levels.

CONCLUSION

We report a significant association of neurobehavioral changes with the prevalence of high Pb levels in Indian children. Additionally significant correlation of BDNF with BLL in these children suggests a causal role of BDNF in Pb induced neurological damage.

Selenium Levels in Occupationally Lead Exposed Workers of Rajasthan

Occupational and environmental exposure to Lead (Pb) has profound detrimental effects on human health. The underlying mechanism of lead toxicity is not fully understood but antioxidant imbalance is suggested to be a key player in its pathogenesis. Selenium (Se) being a vital component of antioxidant system in the body, has been linked to many health benefits in humans. Selenium levels in occupationally Pb exposed individuals has not been explored in Indian setup. The aim of the present study is to find out the association of Se with blood lead levels (BLL) in occupationally Pb exposed individuals. In the present study 91 occupationally Pb exposed workers employed in handicraft and paint industries were recruited after taking informed consent. The demographic details were noted on self-generated questionnaire. The BLL and Se were measured using GFAAS (Thermofisher Scientific, Waltham, USA). Samples were run in duplicate after ensuring quality control. The mean Pb and Se levels in the study population were 5.5 ± 5.6 µg/dl (0.42-31.76 µg/dl) and 105.5 ± 23.8 µg/dl (46.4-189.6 µg/dl) respectively. BLL was significantly higher in tobacco chewers and those occupationally exposed to Pb for more than 5 years. Significantly low Se levels were observed in individuals with high BLL. Statistically significant negative linear relationship was noted between BLL and Se. The negative correlation of Se with BLL indicates the antagonistic relationship between these metals.

Alterations in Th17 and Treg Lymphocyte Subset in Workers Occupationally Exposed to Lead

Occupational exposure to lead (Pb) may have a deleterious effect on health of the workers. Among the various physiological systems, the immune system is one of the most susceptible targets of lead. Previous studies have been inconclusive in establishing the effect of Pb on the immune system. With this background, the aim of our study was to determine the effect of occupational Pb exposure on workers' immune parameters. A total of 110 individuals who were occupationally exposed to Pb and 97 apparently healthy non-exposed individuals were recruited in this study. Blood lead levels (BLL) were determined by atomic absorption spectrophotometry (AAS). Lymphocyte subsets (Th1, Th17, and Tregs) were analyzed using flow cytometry, and the cytokine levels (IL-2, IL-4, IL-6, IL-10, IL-17, and TNF-α) were determined by ELISA. BLL were found to be significantly higher in the exposed group than non-exposed. A significant increase of CD8 cells (%) was observed in the lead-exposed group, while CD4 cells (%), although higher in the exposed group did not differ significantly. Among the T lymphocyte subsets, proportion of Th1 and Tregs was found to be lower in the exposed group with a significant increase in Th17 (%). Additionally, the levels of estimated cytokines suggested a predominant pro-inflammatory response in Pb-exposed workers with significant increase in IL-4, IL-6, and TNF-α, and a significant decrease in IL-2 and IL-10. IL-17 levels did not show any significant difference between the two groups. Increased Th17/Tregs ratio in the exposed group is also suggestive of an increased pro-inflammatory immune response in the exposed group. In conclusion, Pb exposure may induce functional alteration in the immune cells, which may predispose to other abnormalities.

Evaluation of DNA Damage and Expressions of DNA Repair Gene in Occupationally Lead Exposed Workers (Jodhpur, India)

Occupational exposure to lead (Pb) remains a significant concern for worker's health working in different factories. There are many discrepancies among the results regarding the studies of genotoxicity of Pb. The present study aimed to evaluate DNA damage and expressions of DNA repair genes (OGG1, XRCC1, and XPD) in occupationally Pb-exposed workers of Jodhpur, India. The study consisted of 100 occupationally Pb-exposed workers and 100 controls (non-exposed) with no history of occupational exposure. Pb levels were determined by atomic absorption spectrophotometry, serum 8-hydroxy-2-deoxyguanosine (8-OHdG) concentrations were measured by ELISA, and expressions of DNA repair genes (OGG1, XRCC1, and XPD) were estimated by RT-PCR. The results indicated significantly higher levels of Pb in the exposed group as compared with the non-exposed group (p < 0.0001). Serum 8-OHdG concentrations were significantly higher (p < 0.0083), and all three DNA repair genes were significantly downregulated (fold change: OGG1, 0.188; XRCC1, 0.125; XPD, 0.133) in the Pb-exposed group as compared with the non-exposed. In conclusion, the study findings suggest that Pb exposure is associated with increased DNA damage and reduced DNA repair capacity, which may lead to serious health issues in occupationally Pb-exposed workers.

A Study of the Levels of Some Toxic Substances present in Dry Holi Colours in Kolkata, India

'Holi' is an Indian festival with a great cultural context, that is celebrated across the world at the onset of spring by applying dry powder of vibrant colours on friends and family. In ancient times holi colours were prepared from different spring flowers, but in modern times, these natural colours have been replaced by commercial industrial dyes prepared by chemical processes. Even products that claim to use organic colours, use synthetic pigments to enhance the brightness of hues. Such synthetic holi colours are sold as herbal colours, in an unregulated manner, in local markets, and no checks can be enforced on the product composition. Also, the quality and the amount of information about the ingredients of the particular packets are missing. These colours sold in the local market often contain hazardous chemicals such as endotoxins, and heavy metals, like lead, potentially causing moderate to severe health problem. Holi colour samples were randomly collected from different sites in Kolkata, India. Red, pink, violet, green and yellow coloured powders were obtained. The powders were prepared and analysed for lead content by Inductively Coupled Plasma-Mass Spectrometric method. Analysis of endotoxin content of different holi colours was also performed by Limulus Amebocyte Lysate test. The lead content was found to be almost 2 times higher in the holi colours, with yellow pigment having the highest concentration, than FDA Standard for maximum permissible limit in cosmetics, which was taken as a reference for safety limit of lead that is dermatologically applicable. The endotoxin levels are alarmingly high, with almost 35 times the FDA reference for dermatological safety limit. Special attention should be given to lead and endotoxin levels in holi colours as their consequences pose serious health threats. Therefore, quality control measures should be recommended for them, in par with products designed for long-term contact with the skin.

Levels of lead, aluminum, and zinc in occupationally exposed workers of North-Western India

OBJECTIVES

Metals including lead (Pb), aluminum (Al), and zinc (Zn) are widely used in factories such as welding, handicrafts, and paint. Occupational exposure to such metals causes a wide range of biological effects, depending upon the metal levels and duration of exposure. Accumulation of these metals may lead to several adverse health effects such as neurodegenerative diseases and cancer. The study aimed to evaluate Pb, Al, and Zn levels in occupationally exposed workers of North-Western India and create awareness about its toxicity and adverse outcomes.

METHODS

The study included 120 factory workers (exposed) and 100 healthy controls (nonexposed); age ranged 18-78 years. Blood Pb and serum Al was estimated by graphite furnace atomic absorption spectrophotometry and serum Zn was estimated by flame atomic absorption spectrophotometry (ICE 3000, Thermo Fisher Scientific).

RESULTS

Results indicated significantly higher levels of Pb, Al, and Zn in the exposed than the nonexposed. No significant difference was observed in metal levels, based on age and duration of exposure. Painters showed higher blood Pb, whereas welders were found to have higher serum Al and Zn levels.

CONCLUSIONS

To conclude, workers showed higher levels of metals and it may cause deleterious effects on the health of workers occupationally exposed to these metals. Appropriate maintenance regarding worker's safety and hygiene is required to protect them from the harmful effects of these toxic metals.

Estimation of lymphocyte subsets and cytokine levels in workers occupationally exposed to cadmium

INTRODUCTION

Occupational exposure to Cadmium (Cd) may have serious health effect on workers. However, little is known about its effect on immune system. Moreover, previous studies have been inconclusive in stating the effect of Cd on immune system. The aim of our study was to estimate immune parameters in workers occupationally exposed to Cd.

MATERIAL AND METHODS

110 individuals occupationally exposed to Cd and 97 apparently healthy non-exposed individuals were recruited for this study. Blood Cadmium levels were determined by AAS. Lymphocyte subset were analyzed using flow cytometry and the cytokine levels were determined by ELISA.

RESULTS

Exposed group have significantly higher levels of B-Cd. % of CD8 cells were higher in exposed while % of CD4 cells showed a decreasing trend in the exposed group. Among the CD3CD4 T cell subsets Th1 (%) and Tregs (%) cells were lower while Th17 (%) were higher in exposed group. Increased levels of IL-4 (Th2), IL-6 (Th2) and TNF- α (Th1) and decreased levels of IL-2 (Th1) and IL-10 (Tregs) were observed in Cd exposed workers which is indicative of a predominant pro-inflammatory response in Cd exposed workers. IL-17 (Th17) levels did not show any significant difference between the two groups. Increased Th17/Tregs ratio in the exposed group is also suggestive of an increased pro-inflammatory immune response in exposed group.

CONCLUSION

To conclude, even low level of exposure to Cd in occupational settings is associated with alterations in Th17 cells, which may further predispose an individual to other systemic abnormalities.

Assessment of circulating miR-20b, miR-221, and miR-155 in occupationally lead-exposed workers of North-Western India

Lead (Pb), a toxic heavy metal, is capable of inducing several adverse health effects following its accumulation in the body. Lead is a potential carcinogen, capable of causing multisystem alterations. Recent reports identify small regulatory RNA molecules-miRNAs-which show differential expression in individuals exposed to similar levels of lead. These miRNAs can become potential molecular biomarkers of lead toxicity in the future and may unravel the possible molecular pathways through which this metal may exert its toxic manifestations. The present study aimed to assess the circulating levels of miRNA-20b, 221, and 155 in occupationally lead-exposed workers and correlate them with blood lead levels. One hundred ten participants working in various factories of Jodhpur and 97 participants not occupationally exposed to lead were recruited after obtaining due informed consent. Blood lead level (BLL) was estimated by graphite furnace atomic absorption spectrophotometry (GF-AAS). Circulating miRNAs were isolated from serum by Qiagen miRNA isolation kit and converted to cDNA by commercial kit. Expression profiles of miR-20b, miR-221, and miR-155 were performed in RT-PCR using Qiagen miRNA PCR assays. The blood lead level (mean ± SD) of occupationally lead-exposed subjects was 6.94 ± 11.96 μg/dL while that of non-exposed was 2.39 ± 4.66 μg/dL. Out of the three miRNAs, miR-155 and miR-221 were significantly upregulated, while miR-20b did not show significant difference among study groups. The fold change of miR-20b, miR-221 and miR-155 expression were 1.08, 2.71 and 2.07 respectively. Functional analysis revealed that these miRNAs have the potential to trigger various genes and cellular pathways. The findings of our study highlight the importance of miRNA dysregulation in lead-exposed individuals that may contribute to the systemic effects of lead toxicity.

Blood lead and cadmium levels in occupationally exposed workers and their effect on markers of DNA damage and repair

Occupational exposure to heavy metals like lead and cadmium causes a wide range of biological effects and may elevate the risk of genetic damage. Heavy metal toxicity is now becoming a significant public health problem. There are many discrepancies in the results of the studies on the genotoxicity of heavy metals. Therefore, the study aimed to estimate lead, cadmium, and 8-OHdG levels (8-hydroxy-2-deoxyguanosine) and expression of DNA repair gene OGG1 (8-oxoguanine DNA glycosylase 1) in occupationally heavy metal exposed workers. The study comprised 100 workers, occupationally exposed to lead and cadmium from different factories and 100 controls without history of metal exposure. The lead and cadmium mean ± SD were 5.69 ± 12.07 µg/dL and 3.44 ± 1.33 µg/L in the cases and 1.27 ± 1.10 µg/dL and 1.07 ± 0.67 µg/L in the controls. The 8-OHdG concentration was significantly higher in the cases than the controls. Cadmium showed a significant positive correlation with 8-OHdG in the cases. The expression of OGG1 was significantly down-regulated in the cases compared to the controls. Lead levels did not show any significant correlation with OGG1, whereas cadmium level had a significant positive correlation with OGG1 in the cases. To conclude, the exposure to heavy metals is associated with increased oxidative DNA damage and impaired expression of the DNA repair gene, OGG1.

Comprehensive Review of Cadmium Toxicity Mechanisms in Male Reproduction and Therapeutic Strategies

Cadmium (Cd) has been widely studied as an environmental pollutant for many years. Numerous studies have reported that Cd exposure causes damage to the heart, liver, kidneys, and thyroid in vivo. The emerging evidence suggests that Cd exposure induces damage on male reproductive system, which is related to oxidative stress, inflammation, steroidogenesis disruption, and epigenetics. Current preclinical animal studies have confirmed a large number of proteins and intracellular signaling pathways involved in the pathological process of Cd-induced male reproductive damage and potential measures for prophylaxis and treatment, which primarily include antioxidants, anti-inflammatory agents, and essential ion supplement. However, explicit pathogenesis and effective treatments remain uncertain. This review collects data from the literatures, discusses the underlying mechanisms of Cd-induced toxicity on male reproductive function, and summarizes evidence that may provide guidance for the treatment and prevention of Cd-induced male reproductive toxicity.