Autism spectrum disorder: Cadmium and mercury concentrations in different biological samples, a systematic literature review and meta-analysis of human studies.

The present study was conducted to investigate the differences in cadmium (Cd) and mercury (Hg) concentrations between children with autism spectrum disorder (ASD) and controls. In this systematic review and meta-analysis study, three thousand one hundred forty-five studies were collected from scientific databases including Web of Science, Scopus, PubMed, and Google Scholar from January 2000 to October 2022 and were investigated for eligibility. As a result, 37 studies published in the period from 2003 to 2022 met our inclusion criteria and were considered in the meta-analysis. The heterogeneity assumption was evaluated using the Chi-squared-based Q-test and I-squared (I2) statistics. The pooled estimates were shown in the forest plots with Hedges' g (95% confidence interval) values. The random effects model demonstrated that there is no significant difference in the blood (Hedges' g: 0.14, 95% CI: 0.45, 0.72, p > 0.05), hair (Hedges' g: 0.12, 95% CI: 0.26, 0.50, p > 0.05), and urinary (Hedges' g: 0.05, 95% CI: 0.86, 0.76, p > 0.05) Cd levels of the case group versus control subjects. Moreover, the pooled findings of studies showed no significant difference in the blood (Hedges' g: 1.69, 95% CI: 0.09, 3.48, p > 0.05), hair (Hedges' g: 3.42, 95% CI: 1.96, 8.80, p > 0.05), and urinary (Hedges' g: 0.49, 95% CI: 1.29 - 0.30, p > 0.05) Hg concentrations. The results demonstrated no significant differences in Hg and Cd concentrations in different biological samples of children with ASD compared to control subjects.

Evaluation of urinary trace element levels in patients with opioid use disorder undergoing methadone treatment in western Iran.

The monitoring of essential and toxic elements in patients with Opioid Use Disorder (OUD) undergoing methadone treatment (MT) is important, and there is limited previous research on the urinary levels of these elements in MT patients. Therefore, the present study aimed to analyze certain elements in the context of methadone treatment compared to a healthy group. In this study, patients with opioid use disorder undergoing MT (n = 67) were compared with a healthy group of companions (n = 62) in terms of urinary concentrations of some essential elements (selenium (Se), zinc (Zn), copper (Cu), iron (Fe), manganese (Mn), calcium (Ca)) and toxic elements (lead (Pb), cadmium (Cd), arsenic (As), and chromium (Cr)). Urine samples were prepared using the acid digestion method with a mixture of nitric acid and perchloric acid and assessed using the ICP-MS method. Our results showed that the two groups had no significant differences in terms of gender, education level, occupation, and smoking status. Urinary concentrations of Se, Cu, and Fe levels were significantly lower in the MT group compared to the healthy subjects. However, the concentrations of Pb, Cd, As, Mn, Cr, and Ca in the MT group were higher than in the healthy group (p < 0.05). No significant difference was established between the levels of Zn in the two groups (p = 0.232). The results of regression analysis revealed that the differences between the concentration levels of all metals (except Zn) between two groups were still remained significant after adjusting for all variables (p < 0.05). The data obtained in the current study showed lower urinary concentrations of some essential elements and higher levels of some toxic elements in the MT group compared to the healthy subjects. These findings should be incorporated into harm-reduction interventions.

Acrylamide in potato chips in Iran, health risk assessment and mitigation.

This study aimed to determine the acrylamide content in potato chips sold in Kermanshah, Iran and assess the potential health concerns associated with acrylamide exposure. HPLC-DAD was used to analyse 120 samples across 40 brands. The possible non-carcinogenic risk index for adults was below 1 for all 40 brands (100%), but for children it was only below 1 for 9 brands (22.5%) and above 1 for 31 brands (77.5%). Regarding the possible carcinogenic risk index, for adults only 1 out of 40 brands rated > 10-4, whereas for children all brands rated > 10-4. This shows that children's exposure to acrylamide through potato chips consumption in Kermanshah can be considered a risk on cancer and exposure of adults requires attention and monitoring. The best way to reduce acrylamide in potato chips and associated health risks is to improve the production process, especially temperature and time.

The effects of active and passive smoking on selected trace element levels in human milk.

Our study aimed to compare levels of six micro-elements and six potentially toxic elements in the breast milk of non-smoking women compared to those found in women who smoke tobacco and women exposed to second-hand smoke during pregnancy and lactation. This was a cross-sectional study conducted on 100 lactating women in western Iran. The studied subjects were in three groups: passive smokers, active smokers, and a control group. Concentrations of selected trace elements in breast milk (essential and non-essential metals) were determined using ICP-MS. Our results indicated that the parameters of education, fruit consumption, and cosmetics usage had a significant difference among the groups (p < 0.05). Moreover, for trace elements, the Kruskal-Wallis test was statistically significant for arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb) (p < 0.05). The post hoc Dunn test revealed a significant difference in the levels of As, Cd, Hg, and Pb between non-smoker and passive/active smoker groups (p < 0.05). Our findings illustrate that exposure to cigarette smoke can cause an increase in the level of potentially toxic elements in human milk, which is dangerous for the consumption of premature newborns, but more research is needed to evaluate the potential toxic mechanisms of toxic metals.

Human health risk assessment of potentially toxic elements in the breast milk consumed by infants in Western Iran.

This study aimed to assess the human health risk of some toxic metals/metalloids [lead (Pb), mercury (Hg), cadmium (Cd), nickel (Ni), chromium (Cr), and arsenic (As)] on infants via consumption of the breast milk of women living in urban areas of Kermanshah city, west of Iran. After collecting milk samples, the carcinogenic and non-carcinogenic risk assessment as well as uncertainty analysis of toxic metal levels were carried out. The order of concentration of heavy metals/metalloids in the breast milk samples was Cr (41.07 ± 23.19) > Ni (19.25 ± 11.81) > Pb (11.5 ± 4.48) > As (1.96 ± 2.04) > Cd (.72 ± 0.42) > Hg (0.31 ± 0.26). The results revealed that the levels of Cr and Pb in the breast milk samples were exceeded the World Health Organization (WHO) tolerable daily intake. In the breast milk samples a high levels of one of the trace elements As, Cd, Cr, Pb, and Ni were observed (over 73%) and in 40% of them the levels of Cr, Pb, Cd, As, and Ni were all above WHO tolerable daily intake. Moreover, the As-related point assessment of target risk factor (THQ) was higher than the allowable limit only for 1-month-old male neonates and 2-month-old female neonates (THQ > 1). In addition, Cr-related THQ scores were higher at all age and gender groups (THQ > 1). In conclusion, our findings suggest a potential risk of some metals for infants via the consumption of mothers' breast milk.

Accumulation and human health risk assessment of trace elements in two fish species, Cirrhinus mrigala and Oreochromis niloticus, at Tarukri Drain, District Rahimyar Khan, Punjab, Pakistan.

The toxic discharge of heavy metals into the water affects the aquatic ecosystem as well as the human population interacting with it because of their toxicity, bioaccumulation, long persistence, and transfer through the food chain. Thus, it is very important to conduct studies to determine the level of heavy metal pollution in order to better control, manage, and preserve the pollution of aquatic ecosystems. This study assessed heavy metal contamination in fish and its associated health risk to the population around the Tarukri Drain, Punjab, Pakistan. Two fish species (Oreochromis niloticus and Cirrhinus mrigala) were collected from three different sites in two different seasons. Collected fish were analyzed for cadmium (Cd), iron (Fe), lead (Pb), nickel (Ni), and zinc (Zn) accumulation using atomic absorption spectrometer (AAS). Furthermore, the human health risks associated with the consumption of affected fish were also assessed. Target hazardous quotient for seasonal consumers was between 0.12, - 1.58 × 10-4, and 0.54 - 3.28 × 10-4 (mg/kg) in O. niloticus and C. mrigala, respectively. While for regular consumers it was between 0.28-3.71 × 10-4 and 1.27-7.68 × 10-4 (mg/kg) in O. niloticus and C. mrigala respectively for the studied heavy metals. Fish sampled from Sadiqabad contained the highest concentration of heavy metals. The analysis of fish organs (kidney, liver, and muscles) showed heavy metal accumulation in the order of kidney > liver > muscles (p < 0.00). The obtained results showed that heavy metal contaminations in both fish species were within the permissible limits recommended by the World Health Organization (WHO). Both sampling seasons (i.e., summer and winter) showed a non-significant difference in heavy metal concentration. The calculated total target hazardous quotient across all heavy metals remained < 1 with only one exception. The carcinogenic risk assessment of heavy metals showed a non-significant effect in both fish species.

Association of environmental tobacco smoke (ETS) with lead and cadmium concentrations in biological samples of children and women: systematic review and meta-analysis.

OBJECTIVES: Previous literature has shown that heavy metals (HMs) in cigarette smoke have been overestimated, and second-hand smoke (SHS) has recently raised public concern. This study aimed to review the effects of passive tobacco exposure on lead (Pb) and cadmium (Cd) concentrations of children and women in different biological samples. CONTENT: In this systematic review, two independent researchers assessed different databases/search engines including PubMed, Web of Science, Scopus, and Google Scholar using Mesh terms and Text Words. Studies between January 2000 and May 2022 were included. After quality assessment, studies with sufficient data were included in the meta-analysis. A fixed or random model was used to pool the results in a meta-analysis. Heterogeneity between the studies was assessed by using I-square and Q tests. Forest plots demonstrating the point and pooled estimates were provided. SUMMARY: A total of 976 studies were obtained from different databases and finally 17 studies meet our criteria and were included in our systematic review. Out of 17 studies, six studies had sufficient data for analysis and were included in the meta-analysis. The results of the meta-analysis showed a significant difference in blood lead concentrations (BLC) between the children with SHS exposure and the control group (Hedges' g: 2.44, 95% CI: 1.01-3.86, p<0.05). Also, there were significant differences in hair levels of Cd (Hedges' g: 0.66, 95% CI: 0.04, 1.28, p<0.05) and Pb (Hedges' g: 0.94, 95% CI: 0.05, 1.83, p<0.05) between children with SHS exposure compared to the control group. OUTLOOK: The results of the present meta-analysis showed that passive smokers had higher Pb and Cd concentrations than those who were not exposed to cigarette smoke.

Comparison of urine trace element levels in tramadol addiction alone and its co-abuse with cigarette and opium in Western Iran.

Tramadol is an opioid pain medication used to treat moderate to severe pain. Tramadol consumers tend to co-abuse some other substances such as opium, cigarettes, alcohol, and cannabis and each of these substances may impair trace elements homeostasis in the body. Therefore, this case-control study aimed to compare the urinary concentration of some essential and toxic elements in tramadol addiction alone and its co-abuse with cigarette and opium in Western Iran. For this purpose, urine samples were collected in two groups of tramadol (n = 72) and control subjects (n = 62) from March to November 2020. The case group was divided into three groups: tramadol alone, tramadol + opium, and tramadol + cigarettes. Moreover, ICP-MS (Agilent 7900) was used to measure trace element concentrations in the urine samples. Based on our results, Fe was the only element markedly higher among controls as compared to tramadol users (p < 0.001). Moreover, the concentration levels of As appeared to be the same among both groups, but the levels of other elements including Ca, Cd, Cr, Mn, Cu, Zn, Co, Ni, Se, and Pb were all significantly higher among tramadol users as compared to control group. The rank-based regression analysis illustrated that no contribution of sex and age effect was found by the regression model on the levels of all 12 studied elements. While, smoking was found to affect the levels of Fe (ß = 0.163, P = 0.025) and Co (ß = 0.411, p < 0.001) so that smoking reduced Fe levels but elevated Co concentration levels. Abuse of tramadol along with cigarettes and opium increased the concentration of some heavy metals in urine samples compared to the control group. However, these results showed no significant effect of age, sex, smoking habit, and amount of tramadol usage on the levels of trace elements.

Association between trace elements in cancerous and non-cancerous tissues with the risk of breast cancers in western Iran.

This study aimed to assess the tissue content of essential and toxic metals including lead (Pb), cadmium (Cd), arsenic (As), silver (Ag), aluminum (Al), chromium (Cr), copper (Cu), iron (Fe), selenium (Se), and zinc (Zn) in the breast cancerous tissues compared to the non-cancerous tissue. The biopsy specimens of 63 breast cancers along with 63 adjacent healthy tissues in Kurdistan Province, Iran, were collected from 2019 to 2020 and assayed using ICP-MS (Agilent 7900). The results of the Mann-Whitney test illustrated that the concentration of Pb, Cd, As, Cr, Cu, and Se were significantly elevated in cancerous tissue (p < 0.05), while Zn was the only trace element with higher levels in healthy subjects (p < 0.05). Moreover, weak to moderate correlations between elements were observed in the cancerous group including Al-Cr (r=0.60), As-Cu (r=0.52), and Cu-Se (r=0.56). In contrast, no correlation over 0.50 was found between trace elements in the non-cancerous group. Raw risk differences (RDs) accounted for a significant effect for Pb, Cd, As, Ag, Cr, Se, and Zn on the development of breast cancer. In conclusion, elevated levels of As, Cd, Cu, Pb, and Se may contribute to enhancing the risk of breast cancer.

Blood lead concentrations in children with iron deficiency anemia: a systematic review and meta-analysis.

Iron deficiency is the most common nutritional disorder detrimental to the behavior, cognitive performance, immune system, and physical growth of infants and preschool- and school-age children. Iron deficiency anemia (IDA) increases children's susceptibility to some metals, including the highly toxic lead (Pb), but the character of this relationship is still disputed. Thus, this study aimed to review and meta-analyze the association between the IDA and blood lead levels (BLL) among children, based on papers indexed by international scientific databases and published up to September 2021. A search was performed of the literature in several databases including the ISI Web of Science, PubMed, and Scopus. The final papers were assessed concerning their quality based on the Newcastle-Ottawa Scale (NOS) for cross-sectional studies. Moreover, analyses were performed using R statistical software with the "meta" package. Of the 1528 articles found, only 12 studies met the inclusion criteria and were considered in the meta-analysis. Significantly higher BLL in IDA children (SMD = 2.40; CI 95%, 0.93-3.87 µg/L; p = 0.0014) was seen when compared to non-IDA children. Moreover, the pooled OR is equal to 2.75 (CI 95%, 1.10-6.85 µg/L; p = 0.0303) suggesting a higher risk of IDA development among children with BLL > 10 µg/dL. Thus, we recommend systematic monitoring of Fe and Pb levels among children, especially in countries with limited sources of nutritious food. Since only a few studies were available for this meta-analysis, further studies are necessary to examine the association between IDA and BLL in detail.

Association between trace element concentrations in cancerous and non-cancerous tissues with the risk of gastrointestinal cancers in Eastern Iran.

This study was conducted to investigate the association between trace elements including cadmium (Cd), chromium (Cr), cobalt (Co), copper (Cu), iron (Fe), lead (Pb), nickel (Ni), selenium (Se), zinc (Zn), and arsenic (As) in gastrointestinal cancer tissue and non-cancerous tissue (suspected gastrointestinal cancer) in Eastern Iran. The samples of 63 gastrointestinal cancers (stomach (n = 20), esophageal (n = 19), and colorectal (n = 24) along with 63 controls in South Khorasan Province, Iran, were collected and analyzed using ICP-MS (Agilent 7900). Our results indicated that the concentrations of Co (1.3 ± 0.8, 1.3 ± 0.8 µg kg-1), Cr (8.1 ± 7.3, 11.0 ± 14.8 µg kg-1), Ni (29.0 ± 20.1, 39.5 ± 30.2 µg kg-1), Pb (6.9 ± 4.0, 6.1 ± 4.6 µg kg-1), and Zn (867.6 ± 159.1, 935.6 ± 196.2 µg kg-1) were significantly higher among esophagus and colon cancer cases than controls (p < 0.05). Similarly, stomach cancer cases showed higher Co, Cr, Ni, Se, and Zn and lower Cu concentrations than their controls (p < 0.05). Moreover, the Spearman correlation between metals revealed a mostly low to moderate correlation between metals. Our finding illustrated that the significant risk differences of Cr, Ni, Pb, Se, and Zn metals on esophagus cancer when considered the single predictor unadjusted for other metals and covariates RD (95% CI) - Cr: -0.274 (-0.463, -0.086), Ni: -0.288 (-0.457, -0.118), Pb: -0.171 (-0.463, -0.086), Se: -0.243 (-0.434, -0.051), and Zn: -0.094 (-0.143, -0.045) respectively. This study suggests that the trace element's exposure may be associated with gastrointestinal cancer risk. Additional studies are needed to elucidate the mechanisms underlying trace element carcinogenesis further.

Blood lead concentration among oral/inhaled opium users: systematic review and meta-analysis.

Lead is a poisonous heavy metal with various known side effects. The effect of opium on raising blood lead concentration (BLC) has been investigated with no general agreement. In Iran, the number of lead poisoning cases has raised among the opium-addicted population. This systematic review and meta-analysis aim to combine the results of previous studies with the Iranian population to investigate the effect of opium on BLC. In this systematic review, PubMed/Medline, Web of Sciences, Embase, and Scopus were searched for studies using the Iranian population to compare the BLC of opium-addicted cases and non-addicted controls till January 2020. A random-effects model was used to pool the results. I-square test was used to assess the heterogeneity of the studies. The effect sizes were standardized mean differences (proxied by Hedges' g) followed by a 95% confidence interval. Of 417 initial articles, 13 studies met the inclusion criteria to be considered in the meta-analysis. The sample size of eligible studies ranged from 40 to 131 (mean 81.83, SD 27.6). All studies were focused on adults with mean age ranged from 33.5 to 65.15 years old (overall mean 49.0, SD 7.66). There were 13 studies included with 18 Hedges' g effect sizes. Using a random effect model, the pooled effect size was gw = 2.48 (95% CI: 1.58-3.39) and statistically significant in favor of opium-addicted participants. Moreover, heterogeneity was 96.6% (I2=96.6, Q(17) = 504.95, p < 0.001). For studies with large Hedges' g effect sizes (> 4) identified as outliers and removed from meta-analysis. The pooled Hedges' g effect size reduced to 1.39 (95% CI: 0.94-1.85), still highly significant in favor of higher levels of lead in the opium-addicted group. The funnel plot appeared symmetrical confirmed by Egger's test (t = 1.87, p = 0.088), indicating no publication bias present.

Antioxidant properties of dietary supplements of free and nanoencapsulated silymarin and their ameliorative effects on silver nanoparticles induced oxidative stress in Nile tilapia (Oreochromis niloticus).

Silver nanoparticles (AgNPs) are increasingly used in a wide range of products and as a consequence, the environmental concentration will inevitably increase in the near future. Many aquatic organisms have been shown to be sensitive to the toxic effects of silver, including oxidative stress mechanisms. In this study, we assessed the ability of silymarin (Silybum marianum) to counter the oxidative effects of AgNPs in Nile tilapia (Oreochromis niloticus). Fish were fed on the diets supplemented with 50 or 200 mg kg-1 of free or nanoencapsulated silymarin for 50 days. Subsequently, they were exposed via the water to three concentrations (0.05, 0.1, and 0.5 mg L-1) of AgNPs for 24 h, and the effects of this exposure assessed on blood plasma and liver oxidative status. Growth performance and most body indices measured were not affected by any of the experimental diets. There were no effects of free silymarin (FS) or nanoencapsulated silymarin (NS) on levels of plasma aspartate aminotransferase (AST), alanine transaminase (ALT), or on the total protein (TP). In contrast, malondialdehyde (MDA) content, glutathione peroxidase (GPx) activity, and plasma glucose (GLU) were all affected by the high dietary FS and NS treatments compared with controls. Prior to the AgNPs exposure, the levels of SOD and GPx activity were higher and MDA levels lower in the silymarin treatment groups compared to controls. Exposure to AgNPs resulted in a reduction in the levels of GPx and SOD activity and an increase in the level of MDA that was dependent on the exposure concentrations of AgNPs. Based on GPx, MDA, and GLU indices, both forms of silymarin decreased the toxicity of AgNPs, but NS supplementation was the most effective. Thus, we show dietary silymarin supplementation can reduce AgNP toxicity and nanoencapsulation increases its efficacy as an antioxidant.

Metal Risk Assessment Study of Canned Fish Available on the Iranian Market.

Iran is the largest fishery producer in the region reaching nearly 1 million tons. Fish provide a good many nutrients that are beneficial for our health. Due to significant deposits of xenobiotics in the water environments, however, fish may also be a source of non-essential metals, causing a variety of disorders. The main challenges to Iranian fisheries are environmental pollution and quality control, so this study aims to estimate the concentration of cadmium (Cd), mercury (Hg), nickel (Ni), and lead (Pb) in canned tuna fish produced and consumed in Iran. We studied four popular brands (N = 4 × 20) with ICP-MS and then looked at the concentrations and calculated the risk assessment parameters. We found that the lowest concentration was observed for Cd (18 µg/kg) and the highest for Ni (132 µg/kg). Among the brands studied, Pb concentrations differed most (42.0 to 113.3 µg/kg) and Hg levels were more consistent (24.0 and 39.4 µg/kg). The concentrations of Cd, Hg, and Pb in all the brands tested were below EU permissible thresholds. The intake estimation risk assessment parameters (EDI, contribution to PTWI, and CR) and non-cancer risk assessment parameters based on reference doses (THQ and HI) demonstrated the safety of tested products in respect to all metal concentrations studied, while the parameters regarding the toxic effects (MoE, and ILCR) showed that the consumption might cause health risks in terms of Cd (ILCR), Ni (ILCR), and Pb (MoE). The consumption of the canned fish studied should therefore be maintained at a reasonable level (2-5 meals containing fish weekly), so that it may provide necessary nutrients, while avoiding the health risk due to metal content.

Exposure effects of iron oxide nanoparticles and iron salts in blackfish (Capoeta fusca): Acute toxicity, bioaccumulation, depuration, and tissue histopathology.

We assessed the toxicity of iron oxide nanoparticles compared with iron salts in the blackfish (Capoeta fusca). After an acute toxicity assessment, we conducted a chronic exposure to a sub-lethal concentration of Fe3O4 NPs, and iron salts (ferric nitrate (Fe(NO3)3), ferric chloride (FeCl3), ferrous sulfate (FeSO4)) to measure iron uptake over a period of 28 days and then subsequent clearance of the iron uptake in the exposed fish that were transferred to clean water for 28 days. Fe(NO3)3 was the most acutely toxic compound followed by FeCl3, FeSO4, and Fe3O4 NPs. Exposure to Fe3O4 NPs and iron salts induced histopathology anomalies in both gills and intestine that included aneurism, hyperplasia, oedema, fusion of lamellae, lamellar synechiae, and clear signs of necrosis (in the gills) and increases in the number of goblet cells, blood cell counts, and higher numbers of lymphocyte (in the intestine). Fe3O4 NPs showed a higher level of uptake in the body tissues compared with iron salts (p < 0.05) with levels of Fe in the gill > intestine > liver > kidney. Fe was shown to be eliminated most efficiently from the gills, followed by the kidney, then liver and finally the intestine. The highest tissue bioconcentration factors (BCF) occurred in the liver for FeCl3, Fe3O4 NPs, and FeSO4 and in the gills for Fe(NO3)3. We thus show differences in the patterns of tissue accumulation, clearance and toxicological responses for exposures to Fe3O4 NPs and iron salts in blackfish with implications for different susceptibilities for biological effects.

Cadmium and chromium levels in water and edible herbs in a risk assessment study of rural residents living in Eastern Iran.

In arid and semi-arid regions of Iran, water is supplied by qanats, underground channels where pollution is suspected, but unestablished. The aim of this study was thus to run a risk assessment study regarding the levels of cadmium (Cd) and chromium (Cr) in qanat water and edible herbs (Adiantum capillus-verenis, Chara globularis and Plantago lanceolata) growing in qanats in 14 villages in South Khorasan Province in Iran between April and August 2018. Samples were collected in qanats from the same sampling points, and after mineralization in nitric and perchloric acids were analyzed for metal concentrations by means of atomic absorption spectrometry. Concentrations of Cd and Cr found in water were not high (0.028 and 1.091 µg L-1, respectively) and contamination parameters revealed no pollution. The ingestion rate of water and the exposure frequency to metals were the most relevant variables in the model of a sensitivity analysis, but the Hazard Quotient indicated no risk of non-carcinogenic health problems to consumers of the water. The Carcinogenic Risk parameter suggested, however, that there is a risk of these consumers' developing cancer. Concentrations found in herbs were higher than in water but remained below permissible thresholds. Hazard Quotient values of three species studied in the case of children and A. capillus-verenis in the case of adults indicated a potential non-carcinogenic health risk linked with eating them. The study reveals that further research to include many of the qanats across Iran should be carried out to verify the scale of the risk suggested. Graphical abstract.

Urinary Metal Levels with Relation to Age, Occupation, and Smoking Habits of Male Inhabitants of Eastern Iran.

In low-income and middle-income countries such as Iran, smoking is becoming increasingly popular, especially among young people. This has led to additional exposure to a variety of substances, including metals which may exert a toxic influence and lead to severe diseases. In order to evaluate the influence of smoking on metal concentrations, a case-control study of levels of metal in urine was carried out in smokers (n = 64) and non-smokers (n = 35) from the city of Birjand (Iran). They were divided according to their age and socioeconomic status. Concentrations of cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), nickel (Ni), lead (Pb), and zinc (Zn) were measured using ET-AAS. We found higher concentrations of Cd (0.03 vs. 0.12 µg/L), Co (0.6 vs. 1.22 µg/L), and Cr (14.00 vs. 18.17 µg/L) in the urine of smokers. Age and occupation are factors that also influence the levels of metals. Young smokers demonstrate higher Cd and Pb levels than other age groups. It would also appear that public sector workers and self-employed are the sectors most susceptible to high levels of metals.

Thyroid dysfunction: how concentration of toxic and essential elements contribute to risk of hypothyroidism, hyperthyroidism, and thyroid cancer.

This study was conducted to evaluate the levels of trace metals Fe, Cr, Co, Cd, Cu, Ni, Hg, Zn, and Pb in healthy individuals and patients with thyroid disease (hyperthyroidism, hypothyroidism, and cancerous). The serum levels of 110 participants living in Birjand City, east of Iran, were collected and analyzed using ICP-MS (Agilent 7900). Results showed that the concentration levels of Cr, Co, Zn, Cd, and Pb were significantly higher at case-patients (p < 0.05), but the levels of Fe, Ni, and Hg were similar between healthy and patient subjects (p > 0.05). In patients with high or low thyroid activity, strong mutual correlations between Cr, Ni, and Fe were noticeable (p < 0.05). In hypothyroid patients, no significant correlation between Zn and Hg, Co, and Cd was found, but Zn was moderately and positively correlated with other trace metals. The moderate negative correlations between Cd-Cr (p = - 0.46) and Cd-Fe (p = - 0.43) were also observed. Logistic regression analysis showed that the effect of Cr, Co, Pb, Cu, Zn, and Cd was significant in developing hyperthyroidism and hypothyroidism; whereas, in patients with thyroid cancer, the effect of Cr, Cd, and Pb was found to be significant. In conclusion, our findings suggest that toxic metals such as Pb, Cd, and Cr can increase the risk of developing hypothyroidism and thyroid cancer, but more research is needed to evaluate the potential toxicity mechanisms of Pb, Cd, and Cr.

A mini review of bisphenol A (BPA) effects on cancer-related cellular signaling pathways.

Bisphenol A (BPA) is a plasticizer used widely in many industrial products and is now well established as an endocrine-disrupting chemical (EDC). BPA readily leaches out from these products into the environment and into foodstuffs (from packaging materials) and human exposure can be considerable. Many studies have shown that BPA exposure is associated with a range of chronic human health conditions, including diabetes, cardiovascular disorders, polycystic ovarian disease, hepatotoxicity, and various types of cancer. BPA exerts its effects through deregulating cell signaling pathways associated with cell growth, proliferation, migration, invasion, and apoptosis. Previous studies on the molecular mechanisms of BPA have illustrated a variety of pathways impaired at very low exposure concentrations and that stimulate cellular responses relating to tumorigenesis both in cancer onset and progression. In this mini review, the recent advancements made through in vitro analyses are reported on for the effect of BPA on various cellular signaling pathways focusing on the signaling pathways that play a major role in carcinogenesis.

Bioaccumulation and elimination of nickel in the organs of black fish (Capoeta fusca).

Since toxicity is based on the effect that a toxicant produces at a target site within an organism, establishing the relationship between the concentration of substance at the target site and the subsequent toxic effect can provide a tool for predicting toxicity. This article aims to investigate the patterns of bioaccumulation and elimination of nickel in the selected organs of black fish (Capoeta fusca) exposed to two treatments of nickel (4.5 and 12.7 mg/L) for a period of 30 days. Nickel was assayed using Shimadzu AA 680 atomic absorption spectrophotometer, and the results were given as µg/g wet weight. This finding showed that the accumulation patterns of nickel, for lower sub-lethal (LSL) and higher sub-lethal (HSL) concentrations of nickel, are in the following order: gill > liver > muscle > skin. The elimination patterns of nickel are in the following order: gill > skin > muscle > liver, for LSL concentration, and gill > skin > liver > muscle, for HSL concentration of nickel. The results show that the target organ for accumulation and elimination of nickel is gill.