Individual heavy metal exposure and birth outcomes in Shenqiu county along the Huai River Basin in China

Ameliorative mechanism of dietary vitamin d and magnesium on newborn's pulmonary toxicity induced by cadmium

Cadmium (Cd) exposure in mothers can cause respiratory issues in newborns, but the exact toxicity mechanisms are not fully understood. Vitamin D deficiency in Cd-exposed rats is associated with increased cadmium accumulation in tissues. Finding a cost-effective medication that is vital for the body while also reducing the effects of poisoning is crucial in treating poisonings. To investigate the mechanisms of Cd-induced lung toxicity, we examined the impact of prolonged Cd exposure in female rats before pregnancy on newborn lung health, focusing on sera TNF-α level, lung P53, Foxo1 mRNA, and lung VEGF, and BMP-4 protein level. A total of 50 rats were divided into control, Cd, Cd+Vitamin D, Cd+Mg, and Cd + Vitamin D+Mg groups. Cd exposure resulted in higher serum TNF-α levels and a significant rise in P53 mRNA levels. Additionally, the occurrence of hemorrhage, inflammatory cell infiltration, and thickening of alveolar walls decreased following treatment with vitamin D + Mg. Although Cd did not affect the newborns' body weight, it did impair their lung function. These findings suggest that the Cd-induced increase in the P53 gene expression could be alleviated by vitamin D and Mg, along with the elevation of VEGF and BMP-4 proteins and Foxo1 gene expression. The study revealed that environmental toxins can sometimes harm molecules and proteins, leading to damage in critical fetal tissues. However, these issues can be mitigated through essential supplements. STRUCTURED ABSTRACT: The increasing role of Cd in the erratic behavior of numerous biological and molecular entities, notably the development of fetal lung tissue, has made it beneficial to investigate the possible adverse effects of Cd exposure in pregnant mothers and fetal organ development, where instinctive molecular events occur. Researchers are encouraged to create new aspects of medications to reduce clinical symptoms and improve the quality of life due to exposure to metal toxins, particularly in industrialized countries. The present study aimed to evaluate histopathological and molecular modifications of fetal lungs caused by maternal Cd toxicosis and evaluate the possible ameliorating effects of vitamin D and Mg alone and in combination with fetal lung developmental abnormalities, followed by maternal toxin induction, which can be generalized to humans. Fifty female Wistar rats were purchased from the Pasteur Institute of Iran. To induce the model, cadmium at a dose of 2 mg/kg body weight was injected intraperitoneally into the female rats over 28 days before mating (5 days after injection in a week). Afterward, the female rats were randomly divided into type IV polycarbonate cages and mated with healthy male rats. The pregnancy was confirmed by observation of the vaginal plaque, which was subsequently observed, and the number of days of embryo formation was calculated. Subsequently, the pregnant rats were assigned to the following groups and received PBS, vitamin D, Mg, or vitamin D + Mg. At the end of the nine-day treatment period (the 6th day of pregnancy to the 14th day), the neonates were born vaginally, and their body weight and mortality were recorded. The P53 and Foxo1 gene expression levels in the left and right lobes of the homogenized lungs of the newborns in each group were assessed. TNF-alpha was detected in the sera collected from the newborns by ELISA. The isolated left and right lung tissues were homogenized in radioimmunoprecipitation assay (RIPA) buffer and the superior phase was collected to determine the total protein content by Lowry's method and VEGF and BMP-4 protein levels. The obtained lung samples from newborn rats were fixed in a 10% formalin solution for tissue processing. The fixed samples were embedded in paraffin, and serial paraffin sections were prepared for hematoxylin and eosin staining. This study is the first to examine how maternal Cd exposure affects fetal lung development and to estimate the impact of prescribing Mg and vitamin D during pregnancy. The present study assessed the effects of a repeated dose of Cd for 4 weeks before pregnancy on the lung development of newborn rats born to mothers treated with vitamin D and Mg. The results showed that the P53 gene was overexpressed in the model group, while Foxo1 gene expression was downregulated, negatively impacting the lung structure and developmental indices of the fetuses. Therefore, the intake of vitamin D and Mg may contribute to improving the various stages of Cd-induced lung injury by modulating lung inflammation and mucosal secretion while also positively influencing the number of surviving offspring.

Exposure to metal mixtures and adverse pregnancy and birth outcomes: A systematic review

BACKGROUND

Prenatal exposure to metal mixtures is associated with adverse pregnancy and birth outcomes like low birth weight, preterm birth, and small for gestational age. However, prior studies have used individual metal analysis, lacking real-life exposure scenarios.

OBJECTIVES

This systematic review aims to evaluate the strength and consistency of the association between metal mixtures and pregnancy and birth outcomes, identify research gaps, and inform future studies and policies in this area.

METHODS

The review adhered to the updated Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) checklist, along with the guidelines for conducting systematic reviews and meta-analyses of observational studies of etiology (COSMOS-E). Our data collection involved searching the PubMed, MEDLINE, and SCOPUS databases. We utilized inclusion criteria to identify relevant studies. These chosen studies underwent thorough screening and data extraction procedures. Methodological quality evaluations were conducted using the NOS framework for cohort and case-control studies, and the AXIS tool for cross-sectional studies.

RESULTS

The review included 34 epidemiological studies, half of which focused on birth weight, and the others investigated neonate size, preterm birth, small for gestational age, miscarriage, and placental characteristics. The findings revealed significant associations between metal mixtures (including mercury (Hg), nickel (Ni), arsenic (As), cadmium (Cd), manganese (Mn), cobalt (Co), lead (Pb), zinc (Zn), barium (Ba), cesium (Cs), copper (Cu), selenium (Se), and chromium (Cr)) and adverse pregnancy and birth outcomes, demonstrating diverse effects and potential interactions.

CONCLUSION

In conclusion, this review consistently establishes connections between metal exposure during pregnancy and adverse consequences for birth weight, gestational age, and other vital birth-related metrics. This review further demonstrates the need to apply mixture methods with caution but also shows that they can be superior to traditional approaches. Further research is warranted to deeper understand the underlying mechanisms and to develop effective strategies for mitigating the potential risks associated with metal mixture exposure during pregnancy.

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

Background

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

Methods

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

Results

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

Conclusions

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

Determination of toxic metal burden and related risk factors in pregnant women: a biological monitoring in Sabzevar, Iran

Nowadays, the adverse effect of toxic metals on humans is well known, especially in the fetal period such as preventing cognitive development and congenital abnormalities of the central nervous system. Hence, this study aims to evaluate the toxic metal burden in mothers and newborns in Sabzevar. Obtained data can be useful for authorities in public health issues. To determine heavy metals in placental blood and umbilical cord blood, one hundred eighty blood samples were taken from ninety mothers referred to Shahidan Mobini Hospital for delivery. The amount of metals in samples was analyzed using inductively coupled plasma optical emission spectrometry (ICP OES). The results of this study revealed that 21.52%, 26.19%, and 60.71% of maternal blood samples (placental blood) and 16.47%, 56.47%, and 20% of umbilical cord blood samples were higher than the US center for disease control (CDC) recommended levels for Pb, Cd, and As respectively. According to the multiple linear regression analysis, the Pb (p = 0.054), As (p < 0.001), and Se (p < 0.001) levels had an association with the mother's living area. Also, there was a significant association between Se (0.021) and the age of the mother. However, the Se values in its optimum concentrations in the blood (60-140 μg/L) can decrease the adverse effects of toxic metals, 72.5% of the pregnant women had Se values below the 60 μg/L and only 6% of pregnant women had Se levels higher than 140 μg/L. We concluded that the mothers inhabiting the rural areas need more Se sources in their diets.

Investigation of exposure to heavy metals (Hg, Pb, Cd, Co, and Cr) as the cause of congenital anomaly cases (orofacial cleft) in infants

Orofacial cleft (OFC) is one of the most common congenital defects, with worldwide cases occurring in approximately 1:700 to 1:1000 births. This incidence is among the highest birth defects in Indonesia, and the incidence rate in Bandung Regency (14.69%) is the second-highest in West Java province. The purpose of this study was to analyze the association of heavy metal factors that accumulate in infants to the risk of OFC in Bandung Regency. The method was used by testing heavy metals Hg, Pb, Cd, Co, and Cr in infant blood. The total sample were 54 samples, where the case respondent of 32 and 22 respondents as the control group. Blood samples were analyzed using ICP-MS Agilent 7900. The correlation using statistic analyze namely chi-square analysis (bivariate) and multiple logistic regression (multivariate). The results showed that there was a significant difference in the concentration of heavy metals Hg, Pb, and Cd as well as an increase in Pb and Cd in the infant's blood which was thought to be significantly associated with the risk of OFC.

A systematic review of adverse health effects associated with oral cadmium exposure

Scientific data characterizing the adverse health effects associated with dietary cadmium (Cd) exposure were identified in order to make informed decisions about the most appropriate toxicological reference value (TRV) for use in assessing dietary Cd exposure. Several TRVs are available for Cd and regulatory organizations have used epidemiologic studies to derive these reference values; however, risk of bias (RoB) evaluations were not included in the assessments. We performed a systematic review by conducting a thorough literature search (through January 4, 2020). There were 1714 references identified by the search strings and 328 studies identified in regulatory assessments. After applying the specific inclusion and exclusion criteria, 208 studies (Human: 105, Animal: 103) were considered eligible for further review and data extraction. For the epidemiologic and animal studies, the critical effects identified for oral Cd exposure from the eligible studies were a decrease in bone mineral density (BMD) and renal tubular degeneration. A RoB analysis was completed for 49 studies (30 epidemiological and 19 animal) investigating these endpoints. The studies identified through the SR that were considered high quality and low RoB (2 human and 5 animal) can be used to characterize dose-response relationships and inform the derivation of a Cd TRV.

Monitoring of urinary arsenic (As) and lead (Pb) among a sample of pregnant Iranian women

PURPOSE

Heavy metals, as significant toxic environmental contaminants, can cause serious adverse health outcomes on the human body even in trace concentrations. There is limited evidence on heavy metal concentrations existing in the body fluids of pregnant women. This study aims to evaluate the urinary levels of arsenic (As) and lead (Pb), as two main toxic heavy metals, among pregnant women and their lifestyle determinants.

METHODS

The study was performed in 2019-2020 in Isfahan, Iran. A number of 140 urine samples of pregnant women who were in their first pregnancy trimester were examined. Inductively coupled plasma optical emission spectrometry (ICP-OES) was applied to analyze the urinary concentrations of As and Pb. Socio-demographic data including age, pre-pregnancy body mass index (BMI), education status, and family income, as well as the use of cleaning products (cosmetic and household cleaning products), and lifestyle habits (food intake, smoking, and physical activity) were collected using a validated questionnaire.

RESULTS

The mean concentration of As and Pb were 8.14 ± 10.8 and 9.6 ± 7.1 μg/g creatinine, respectively. The mean urinary concentration of Pb indicated significant differences in the levels of cosmetic usage, second-hand smoking exposure, and the use of Copper, Aluminum, Teflon, Steel, and Enameled utensils for cooking (p-value < 0.05). Furthermore, the mean of urinary Pb concentrations at high levels of physical activity and scratched utensils using was significantly different from the other categories (p-value = 0.02). No significant differences were found between As and Pb concentration with other socio-demographic factors.

CONCLUSION

The lifestyle determinants and cosmetic products use are important predictors of urinary heavy metals in pregnant women, rather than sociodemographic characteristics. Additional research is necessary to determine long-term adverse birth outcomes of exposure to these heavy metals.

Early pregnancy exposure to metal mixture and birth outcomes - A prospective study in Project Viva

BACKGROUND

Prenatal exposure to metals has been individually associated with birth outcomes. However, little is known about the effect of metal mixture, particularly at low exposure levels.

OBJECTIVES

To estimate individual and joint effects of metal mixture components on birth outcomes.

METHODS

We used data from 1,391 mother-infant pairs in Project Viva (1999-2002). We measured 11 metals in maternal 1st trimester erythrocyte; abstracted birth weight from medical records; calculated gestational age from last menstrual period or ultrasound; and obtained birth length (n = 729) and head circumference (n = 791) from research measurements. We estimated individual and joint effects of metals using multivariable linear and Bayesian kernel machine regressions.

RESULTS

In both single metal and metal mixture analyses, exposure to higher concentrations of arsenic was associated with lower birth weight in males, zinc with higher head circumference in females, and manganese with higher birth length in sex-combined analysis. We also observed sex-specific metal interactions with birth outcomes. Arsenic and manganese showed a synergistic association with birth weight in males, in whom an interquartile range (IQR) increase in arsenic was associated with 25.3 g (95% CI: -79.9, 29.3), 47.9 g (95% CI: -98.0, 2.1), and 72.2 g (95% CI: -129.8, -14.7) lower birth weight when manganese concentrations were at 25th, 50th, and 75th percentiles, respectively. Lead and zinc showed an antagonistic association with head circumference in males, where an IQR increase in lead was associated with 0.18 cm (95% CI: -0.35, -0.02), 0.10 cm (95% CI: -0.25, 0.04), 0.03 cm (95% CI: -0.2, 0.14) smaller head circumference when zinc concentrations were at 25th, 50th, and 75th percentiles, respectively. Exposure to higher concentrations of arsenic was also associated with lower gestational age in males when concentrations of manganese and lead were higher.

DISCUSSION

Maternal erythrocyte concentrations of arsenic, manganese, lead, and zinc were individually and interactively associated with birth outcomes. The associations varied by infant sex and exposure level of other mixture components.

Prenatal exposure to chromium (Cr) and nickel (Ni) in a sample of Iranian pregnant women: urinary levels and associated socio-demographic and lifestyle factors

Heavy metals have been well documented to pose detrimental health effects. The current study aimed to measure the concentration of chromium (Cr) and nickel (Ni) in urinary samples of Iranian pregnant females and determine their potential correlations with different lifestyle variables. The study was conducted in 2019-2020 in Isfahan, Iran, and the urine samples were collected from 140 pregnant women. The concentrations of Cr and Ni in the urinary samples were measured by inductively coupled plasma optical emission spectrometry (ICP-OES). Data on socio-demographic characteristics, use of cleaning products, and lifestyle profiles was collected by validated questionnaires. Cr and Ni were detected in 100% of urinary samples with the mean concentration of 4.1±3.4 and 7.5±4.8 μg/g creatinine, respectively. Significant associations were found between the mean concentration of Cr and Ni with using cooking utensils made of copper, aluminum, Teflon, steel, and enameled, as well as with cosmetic use, and second-hand smoking exposure during pregnancy. The results also showed that the mean urinary Ni and Cr concentrations were significantly different among individuals who consumed seafood and canned food (p-value <0.05). Furthermore, the mean of urinary Cr and Ni concentrations at high levels of physical activity and scratched utensils used was significantly different from the other categories (p-value <0.05). According to our findings, the lifestyle determinants and cosmetic products had superiority to socio-demographic characteristics in predicting urinary heavy metals in Iranian pregnant women.

An Innovative Digestion Method: Ultrasound-Assisted Electrochemical Oxidation for the Onsite Extraction of Heavy Metal Elements in Dairy Farm Slurry

Dairy farm slurry is an important biomass resource that can be used as a fertilizer and in energy utilization and chemical production. This study aimed to establish an innovative ultrasound-assisted electrochemical oxidation (UAEO) digestion method for the rapid and onsite analysis of the heavy metal (HM) contamination level of dairy slurry. The effects of UAEO operating parameters on digestion efficiency were tested based on Cu and Zn concentrations in a dairy slurry sample. The results showed that Cu and Zn digestion efficiency was (96.8 ± 2.6) and (98.5 ± 2.9)%, respectively, with the optimal UAEO operating parameters (digestion time: 45 min; ultrasonic power: 400 W; NaCl concentration: 10 g/L). The digestion recovery rate experiments were then operated with spiked samples to verify the digestion effect on broad-spectrum HMs. When the digestion time reached 45 min, all digestion recovery rates exceeded 90%. Meanwhile, free chlorine concentration, particle size distribution, and micromorphology were investigated to demonstrate the digestion mechanism. It was found that 414 mg/L free chorine had theoretically enough oxidative ability, and the ultrasound intervention could deal with the blocky undissolved particles attributed to its crushing capacity. The results of particle size distribution showed that the total volume and bulky particle proportion had an obvious decline. The micromorphology demonstrated that the ultrasound intervention fragmented the bulky particles, and electrochemical oxidation made irregular blocky structures form arc edge and cellular structures. The aforementioned results indicated that UAEO was a novel and efficient method. It was fast and convenient. Additionally, it ensured digestion efficiency and thus had a good application prospect.

A metabolomic study on the association of exposure to heavy metals in the first trimester with primary tooth eruption

BACKGROUND

The influence of prenatal heavy metals exposure on primary tooth eruption in humans is rarely reported.

AIM

Based on the cohort study design, we investigated the association of exposure to 12 heavy metals in the first trimester with primary tooth eruption, and the maternal metabolisms in the first trimester which might be related to the above relationship.

METHODS

Maternal urine samples were collected in their first trimester, and 12 metals (Ti, V, Fe, Co, Cu, As, Se, Cd, Sn, Hg, Tl, U) were measured using the inductively coupled plasma mass spectrometry method. The maternal metabolome in the first trimester was analyzed by ultrahigh performance liquid chromatography coupled mass spectrometry based metabolomics using urine samples. The infant's first tooth eruption time and number of teeth at age one were recorded by oral examination and questionnaire.

RESULTS

No significant associations were observed between heavy metals exposure in the first trimester and primary tooth eruption, except for Co. The level of Co was positively associated with time of infant's first tooth eruption, and was negatively associated with the number of teeth at age one. Based on metabolomic profiling, glycine was revealed as the key mediating metabolite, which showed negative correlation with Co and opposite effect of Co in the primary tooth eruption.

CONCLUSIONS

Prenatal Co exposure in the first trimester might delay the primary tooth eruption in children through the decreased glycine-disrupted dentin formation, providing the first evidence and novel insights into the control of prenatal heavy metals exposure for ensuring normal (timely) primary tooth eruption.