Chronic Arsenic Exposure and Adverse Pregnancy Outcomes in Bangladesh

Arsenic induces ferroptosis in HTR-8/SVneo cells and placental damage

Placenta ferroptosis has been proven to be associated with a variety of adverse pregnancy outcomes. Arsenic, a conventional metal noxious substance, has garnered considerable attention due to traversing the placental barrier. How arsenic induces placental ferroptosis and reproductive developmental toxicities remains largely unknown. Herein, we investigated the impact of sodium arsenite (As (III)) on iron homeostasis in the placenta through both in vivo and in vitro experiments by using HTR-8/SVneo cells and ICR pregnant mice. As (III) up-regulated the expression of genes or proteins associated with iron uptake (TFRC, DMT1), iron storage (FTH, FTL), ferritin autophagy (NCOA4), and heme degradation (HO-1), and induced cell iron overload. Additionally, accumulation of the lipid hydroperoxide malondialdehyde within cells was triggered by As (III) through inhibition of the Nrf2/GPX4 signal pathway, which resulted in cellular ferroptosis. Fer-1 effectively alleviated the suppression of GPX4 induced by As (III), reduced the accumulation of intracellular lipid peroxidation product MDA, and mitigated cellular ferroptosis. As (III) affected the iron homeostasis, as evidenced by the abnormal iron accumulation in the placenta. Placental structural abnormalities and hemorrhage may be the reason for As (III) causing placental injury and subsequent poor pregnancy outcomes. This study provides new insights into understanding the mechanisms by which As (III) produces placental damage and possible fetal developmental toxicity.

Corrective role of endophytic exopolysaccharides from Clerodendrum infortunatum L. on arsenic-induced ovarian steroidogenic dysfunction and associated inflammatory responses

The present investigation aimed to evaluate the therapeutic potential of exopolysaccharides (EPSs) derived from endophytic fungi against arsenic [As(III)]-mediated metabolic and reproductive ailments. Two endophytic fungi, Diaporthe arengae (CleR1) and Fusarium proliferatum (CleR3), were isolated from Clerodendrum infortunatum (Cle), and used for the extraction of two types of EPSs. GC-MS analysis confirmed the presence of hydroxymethyl furfural (HMF) and α-d-glucopyranose in the EPS1 (CleR1) and EPS2 (CleR3), respectively. FTIR analysis revealed the potential As(III)-chelation properties of both EPSs. EPS1 and EPS2 significantly mitigated As(III)-induced oxidative stress and lipid peroxidation by restoring the activities of antioxidative enzymes. EPSs successfully corrected the gonadotropin imbalance and steroidogenic alterations. The downregulation of proinflammatory (NF-κB and TNF-α) and proapoptotic (BAX) mediators and the upregulation of antiapoptotic (Bcl-2) markers were also detected following the treatment with EPSs. Histomorphological restoration of reproductive and metabolic organs was also observed in both the EPS groups. Moreover, the As(III)-induced increase in the immunoreactivity of the androgen receptor (AR) was successfully reversed by these EPSs. Molecular docking predicted that HMF and α-d-glucopyranose of EPS1 and EPS2 interact with the active site of AR by limiting its activity. Hence, EPS could be effective for developing new therapeutic strategies for managing As(III) toxicity.

Environmental exposure to metal(loid)s and hypertensive disorders of pregnancy: A systematic review

BACKGROUND

Environmental exposure to metal(loid)s has been associated with adverse effects on human health, but the systemic repercussion of these elements on the development of hypertensive disorders of pregnancy (HDP) is still poorly understood.

OBJECTIVE

To summarize evidence published about the influence of environmental exposure to aluminum, arsenic, barium, cadmium, lead, strontium and mercury on the development of HDP.

METHODS

We conducted a systematic literature review according to the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The search strategy was validated by the Peer Review of Electronic Search Strategies. We searched for articles published up to February 2023 in seven databases without language restriction. Two researchers conducted the steps for selection, data extraction and evaluation of the methodological quality of the instruments for epidemiological studies of the Joanna Briggs Institute. Any disagreements were resolved by a third researcher.

RESULTS

We obtained 5076 records, of which 37 articles met the inclusion criteria moderate to high methodological quality. Single exposure to metal(loid)s was predominant, and the leading biological matrix analyzed to detect the concentrations from exposure was maternal blood. Lead was the metal investigated the most, and had the largest number of studies showing positive association with HDP. In relation to the other metal(loid)s, higher levels were found in women with HDP in comparison with healthy women, but the finding of a cause-effect relationship was inconsistent.

CONCLUSIONS

Although we found evidence of harmful effects of the metal(loid)s studied on human health, the results were inconclusive with regard to HDP. Longitudinal studies that consider prospective investigation, adjustment of confounding factors and the interference of other contaminants in the exacerbation of oxidative stress in women from the preconception phase to the puerperal period should be encouraged.

Receipt of hepatitis E vaccine and fetal loss in rural Bangladesh: further analysis of a double-blind, cluster-randomised, controlled trial

BACKGROUND

Vaccination constitutes an attractive control measure for hepatitis E virus (HEV), a major cause of maternal and perinatal mortality globally. Analysis of pregnant participants in an effectiveness trial of the HEV vaccine HEV239 showed possible HEV239-associated fetal losses. We aimed to conduct a detailed analysis of this safety signal.

METHODS

In a double-blind, cluster-randomised trial, 67 villages in Matlab, Bangladesh, were randomly allocated (1:1) to two vaccine groups, in which non-pregnant women aged 16-39 years received either HEV239 (HEV239 group) or Hepa-B (a hepatitis B vaccine; control group). We implemented weekly surveillance for pregnancy detection, and follow-up of pregnancies once every 2 weeks, using physician-confirmed diagnoses to evaluate fetal loss outcomes (miscarriage [spontaneous abortion], stillbirth, and elective termination). Data from a parallel system of reproductive health surveillance in Matlab were used to clarify study diagnoses when necessary. Miscarriage was assessed only among participants whose first positive pregnancy test and vaccination date (for whichever dose was closest to the date of last menstrual period [LMP]) were before 20 weeks' gestation. We defined the following analysis periods of interest: from 90 days before the LMP until the pregnancy outcome (the proximal period); from the LMP date until the pregnancy outcome (the pregnancy period); from 90 days before the LMP until the LMP date (90 days pre-LMP period); and from enrolment until 90 days before the LMP (the distal period). Both Poisson and Cox regression models were used to assess the associations between receipt of HEV239 and fetal loss outcomes. The trial was registered with ClinicalTrials.gov (NCT02759991).

FINDINGS

Among the 19 460 non-pregnant participants enrolled in the trial, 5011 were identified as having pregnancies within 2 years following vaccination and met the criteria for analysis (2407 in the HEV239 group and 2604 in the control group). Among participants vaccinated in the proximal period and evaluated for miscarriage, miscarriage occurred in 54 (8·9%) of 607 in the HEV239 group and 32 (4·5%) of 719 in the control group (adjusted relative risk [aRR] 2·0 [95% CI 1·3-3·1], p=0·0009). Similarly, the risk of miscarriages was increased in the HEV239 group versus the control group among participants inadvertently vaccinated during pregnancy (22 [10·5%] miscarriages among 209 participants in the HEV239 group vs 14 [5·3%] of 266 in the control group; aRR 2·1 [95% CI 1·1-4·1], p=0·036) and among those vaccinated within 90 days pre-LMP (32 [8·0%] of 398 vs 18 [4·0%] of 453; 1·9 [1·1-3·2], p=0·013). No increased risk of miscarriage was observed in those who received HEV239 in the distal period (93 [5·6%] of 1647 vs 80 [4·5%] of 1773; 1·3 [0·8-1·9], p=0·295). Stillbirth and elective termination showed no increased risk among women administered HEV239 versus those administered Hepa-B in any of the analysis periods.

INTERPRETATION

HEV239 given shortly before or during pregnancy was associated with an elevated risk of miscarriage. This association poses a possible safety concern for programmatic use of HEV239 in women of childbearing age.

FUNDING

Research Council of Norway and Innovax.

Prenatal arsenite exposure alters maternal cardiac remodeling during late pregnancy

Exposure to inorganic arsenic through drinking water is widespread and has been linked to many chronic diseases, including cardiovascular disease. Arsenic exposure has been shown to alter hypertrophic signaling in the adult heart, as well as in utero offspring development. However, the effect of arsenic on maternal cardiac remodeling during pregnancy has not been studied. As such, there is a need to understand how environmental exposure contributes to adverse pregnancy-related cardiovascular events. This study seeks to understand the impact of trivalent inorganic arsenic exposure during gestation on maternal cardiac remodeling in late pregnancy, as well as offspring outcomes. C57BL/6 J mice were exposed to 0 (control), 100 or 1000 μg/L sodium arsenite (NaAsO2) beginning at embryonic day (E) 2.5 and continuing through E17.5. Maternal heart function and size were assessed via transthoracic echocardiography, gravimetric measurement, and histology. Transcript levels of hypertrophic markers were probed via qRT-PCR and confirmed by western blot. Offspring outcomes were assessed through echocardiography and gravimetric measurement. We found that maternal heart size was smaller and transcript levels of Esr1 (estrogen receptor alpha), Pgrmc1 (progesterone receptor membrane component 1) and Pgrmc2 (progesterone receptor membrane component 2) reduced during late pregnancy with exposure to 1000 μg/L iAs vs. non-exposed pregnant controls. Both 100 and 1000 μg/L iAs also reduced transcription of Nppa (atrial natriuretic peptide). Akt protein expression was also significantly reduced after 1000 μg/L iAs exposure in the maternal heart with no change in activating phosphorylation. This significant abrogation of maternal cardiac hypertrophy suggests that arsenic exposure during pregnancy can potentially contribute to cardiovascular disease. Taken together, our findings further underscore the importance of reducing arsenic exposure during pregnancy and indicate that more research is needed to assess the impact of arsenic and other environmental exposures on the maternal heart and adverse pregnancy events.

The Siren Song of Cicadas: Early-Life Pesticide Exposure and Later-Life Male Mortality

This paper studies the long-term effects of in-utero and early-life exposure to pesticide use on adulthood and old-age longevity. We use the cyclical emergence of cicadas in the eastern half of the United States as a shock that raises the pesticide use among tree crop growing farmlands. We implement a difference-in-difference framework and employ Social Security Administration death records over the years 1975-2005 linked to the complete count 1940 census. We find that males born in top-quartile tree-crop counties and exposed to a cicada event during fetal development and early-life live roughly 2.2 months shorted lives; those with direct farm exposure face a reduction of nearly a year. We provide empirical evidence to examine mortality selection before adulthood, endogenous fertility, and differential data linkage rates. Additional analyses suggests that reductions in education and income during adulthood are potential mechanisms of impact. Our findings add to our understanding of the relevance of early-life insults for old-age health and mortality.

Update of the risk assessment of inorganic arsenic in food

The European Commission asked EFSA to update its 2009 risk assessment on arsenic in food carrying out a hazard assessment of inorganic arsenic (iAs) and using the revised exposure assessment issued by EFSA in 2021. Epidemiological studies show that the chronic intake of iAs via diet and/or drinking water is associated with increased risk of several adverse outcomes including cancers of the skin, bladder and lung. The CONTAM Panel used the benchmark dose lower confidence limit based on a benchmark response (BMR) of 5% (relative increase of the background incidence after adjustment for confounders, BMDL05) of 0.06 μg iAs/kg bw per day obtained from a study on skin cancer as a Reference Point (RP). Inorganic As is a genotoxic carcinogen with additional epigenetic effects and the CONTAM Panel applied a margin of exposure (MOE) approach for the risk characterisation. In adults, the MOEs are low (range between 2 and 0.4 for mean consumers and between 0.9 and 0.2 at the 95th percentile exposure, respectively) and as such raise a health concern despite the uncertainties.

Mechanisms Associated with Cognitive and Behavioral Impairment Induced by Arsenic Exposure

Arsenic (As) is a metalloid naturally present in the environment, in food, water, soil, and air; however, its chronic exposure, even with low doses, represents a public health concern. For a long time, As was used as a pigment, pesticide, wood preservative, and for medical applications; its industrial use has recently decreased or has been discontinued due to its toxicity. Due to its versatile applications and distribution, there is a wide spectrum of human As exposure sources, mainly contaminated drinking water. The fact that As is present in drinking water implies chronic human exposure to this metalloid; it has become a worldwide health problem, since over 200 million people live where As levels exceed safe ranges. Many health problems have been associated with As chronic exposure including cancer, cardiovascular diseases, gastrointestinal disturbances, and brain dysfunctions. Because As can cross the blood-brain barrier (BBB), the brain represents a target organ where this metalloid can exert its long-term toxic effects. Many mechanisms of As neurotoxicity have been described: oxidative stress, inflammation, DNA damage, and mitochondrial dysfunction; all of them can converge, thus leading to impaired cellular functions, cell death, and in consequence, long-term detrimental effects. Here, we provide a current overview of As toxicity and integrated the global mechanisms involved in cognitive and behavioral impairment induced by As exposure show experimental strategies against its neurotoxicity.

Prenatal Arsenite Exposure Alters Maternal Cardiac Remodeling During Late Pregnancy

Exposure to inorganic arsenic through drinking water is widespread and has been linked to many chronic diseases, including cardiovascular disease. Arsenic exposure has been shown to alter hypertrophic signaling in the adult heart, as well as in-utero offspring development. However, the effect of arsenic on maternal cardiac remodeling during pregnancy has not been studied. As such, there is a need to understand how environmental exposure contributes to adverse pregnancy-related cardiovascular events. This study seeks to understand the impact of trivalent inorganic arsenic exposure during gestation on maternal cardiac remodeling in late pregnancy, as well as offspring outcomes. C57BL/6J mice were exposed to 0 (control), 100 or 1000 µg/L sodium arsenite (NaAsO 2 ) beginning at embryonic day (E) 2.5 and continuing through E17.5. Maternal heart function and size were assessed via transthoracic echocardiography, gravimetric measurement, and histology. Transcript levels of hypertrophic markers were probed via qRT-PCR and confirmed by western blot. Offspring outcomes were assessed through echocardiography and gravimetric measurement. We found that exposure to 1000 µg/L iAs abrogated normal physiologic growth of the maternal heart during late pregnancy and reduced transcript levels of estrogen receptor alpha (ERα), progesterone receptor membrane component 1 (Pgrmc1) and progesterone receptor membrane component 2 (Pgrmc2). Both 100 and 1000 µg/L iAs also reduced transcription of protein kinase B (Akt) and atrial natriuretic peptide (ANP). Akt protein expression was also significantly reduced after 1000 µg/L iAs exposure in the maternal heart with no change in activating phosphorylation. This significant abrogation of maternal cardiac hypertrophy suggests that arsenic exposure during pregnancy can potentially contribute to cardiovascular disease. Taken together, our findings further underscore the importance of reducing arsenic exposure during pregnancy and indicate that more research is needed to assess the impact of arsenic and other environmental exposures on the maternal heart and adverse pregnancy events.

Environmental pollutants and their effects on human health

Numerous environmental contaminants significantly contribute to human disease, affecting climate change and public and individual health, resulting in increased mortality and morbidity. Because of the scarcity of information regarding pollution exposure from less developed nations with inadequate waste management, higher levels of poverty, and limited adoption of new technology, the relationship between pollutants and health effects needs to be investigated more. A similar situation is present in many developed countries, where solutions are only discovered after the harm has already been done and the necessity for safeguards has subsided. The connection between environmental toxins and health needs to be better understood due to difficulties in quantifying exposure levels and a lack of systematic monitoring. Different pollutants are to blame for both chronic and acute disorders. Additionally, research becomes challenging when disease problems are seen after prolonged exposure. This review aims to discuss the present understanding of the association between environmental toxins and human health in bridging this knowledge gap. The genesis of cancer and the impact of various environmental pollutants on the human body's cardiovascular, respiratory, reproductive, prenatal, and neural health are discussed in this overview.

Arsenic in brown rice: do the benefits outweigh the risks?

Brown rice has been advocated for as a healthier alternative to white rice. However, the concentration of arsenic and other pesticide contaminants is greater in brown rice than in white. The potential health risks and benefits of consuming more brown rice than white rice remain unclear; thus, mainstream nutritional messaging should not advocate for brown rice over white rice. This mini-review aims to summarize the most salient concepts related to dietary arsenic exposure with emphasis on more recent findings and provide consumers with evidence of both risks and benefits of consuming more brown rice than white rice. Despite risk-benefit assessments being a challenging new frontier in nutrition, researchers should pursue an assessment to validate findings and solidify evidence. In the interim, consumers should be cognizant that the dose of arsenic exposure determines its toxicity, and brown rice contains a greater concentration of arsenic than white rice.

Effects of chronic exposure to arsenic on the fecal carriage of antibiotic-resistant Escherichia coli among people in rural Bangladesh

Antibiotic resistance is a leading cause of hospitalization and death worldwide. Heavy metals such as arsenic have been shown to drive co-selection of antibiotic resistance, suggesting arsenic-contaminated drinking water is a risk factor for antibiotic resistance carriage. This study aimed to determine the prevalence and abundance of antibiotic-resistant Escherichia coli (AR-Ec) among people and drinking water in high (Hajiganj, >100 μg/L) and low arsenic-contaminated (Matlab, <20 μg/L) areas in Bangladesh. Drinking water and stool from mothers and their children (<1 year) were collected from 50 households per area. AR-Ec was detected via selective culture plating and isolates were tested for antibiotic resistance, arsenic resistance, and diarrheagenic genes by PCR. Whole-genome sequencing (WGS) analysis was done for 30 E. coli isolates from 10 households. Prevalence of AR-Ec was significantly higher in water in Hajiganj (48%) compared to water in Matlab (22%, p <0.05) and among children in Hajiganj (94%) compared to children in Matlab (76%, p <0.05), but not among mothers. A significantly higher proportion of E. coli isolates from Hajiganj were multidrug-resistant (83%) compared to isolates from Matlab (71%, p <0.05). Co-resistance to arsenic and multiple antibiotics (MAR index >0.2) was observed in a higher proportion of water (78%) and child stool (100%) isolates in Hajiganj than in water (57%) and children (89%) in Matlab (p <0.05). The odds of arsenic-resistant bacteria being resistant to third-generation cephalosporin antibiotics were higher compared to arsenic-sensitive bacteria (odds ratios, OR 1.2-7.0, p <0.01). WGS-based phylogenetic analysis of E. coli isolates did not reveal any clustering based on arsenic exposure and no significant difference in resistome was found among the isolates between the two areas. The positive association detected between arsenic exposure and antibiotic resistance carriage among children in arsenic-affected areas in Bangladesh is an important public health concern that warrants redoubling efforts to reduce arsenic exposure.

Testing the Limit: Evaluating Drinking Water Arsenic Regulatory Levels Based on Adverse Pregnancy Outcomes in Bangladesh

(1) Background: Arsenic (As) is a common drinking water contaminant that is regulated as a carcinogen. Yet, As is a systemic toxicant and there is considerable epidemiological data showing As adversely impacts reproductive health. This study used data from a birth cohort in Bangladesh (2008−2011) to examine associations between drinking water As levels and reproductive outcomes. (2) Methods: Pregnant individuals (n = 1597) were enrolled at <16 weeks gestation and drinking water As was measured. Participants with live births (n = 1130) were propensity score matched to participants who experienced miscarriage (n = 132), stillbirth (n = 72), preterm birth (n = 243), and neonatal mortality (n = 20). Logistic regression was used to examine drinking water As recommendations of 50, 10, 5, 2.5, and 1 µg/L on the odds of adverse birth outcomes. (3) Results: The odds of miscarriage were higher for pregnant women exposed to drinking water ≥2.5 versus <2.5 µg As/L [adjusted odds ratio (OR) 1.90, 95% Confidence Interval (CI): 1.07−3.38)]. (4) Conclusions: These preliminary findings suggest a potential threshold where the odds of miscarriage increases when drinking water As is above 2.5 µg/L. This concentration is below the World Health Organizations and Bangladesh’s drinking water recommendations and supports the re-evaluation of drinking water regulations.

Human risk assessment of ash soil after 2020 wildfires in Pantanal biome (Brazil)

Wildfires have increased in the last years and, when caused by intentional illegal burnings, are frequently run out of control. Wildfire has been pointed out as an important source of polycyclic aromatic hydrocarbons (PAHs) and trace elements (TEs) — such as, As, Ni, and Pb — to environmental compartments, and thus may pose a risk to human health and to the ecosystem. In 2020, the Brazilian biome, Pantanal, faced the largest losses by wildfires in the last 22 years. Ashes from the topsoil layer in Pantanal were collected after these wildfires at 20 sites divided into the sediment, forest, PF, PS, and degraded sites. Toxicity and associated risks for human health were also evaluated. The areas highly impacted by wildfires and by artisanal gold mining activities showed higher concentrations for TEs and PAHs than the protected areas. Pb varied from 8 ± 4 to 224 ± 81 mg kg⁻¹, and total PAH concentration ranged between 880 ± 314 and 1350 ± 70 ng g⁻¹, at sites impacted by anthropogenic activities. Moreover, health risk assessments for TE and PAH indicated a potentially great risk for children and adults, via ingestion, inhalation, and dermal pathway. The carcinogenic risks exceeded reference values, for both TE and PAH, suggesting harmful conditions, especially for vulnerable groups, such as children and the elderly.

Maternal Folate Status and the Relation between Gestational Arsenic Exposure and Child Health Outcomes

Gestational arsenic exposure adversely impacts child health. Folate-mediated 1-carbon metabolism facilitates urinary excretion of arsenic and may prevent arsenic-related adverse health outcomes. We investigated the potential for maternal folate status to modify associations between gestational arsenic exposure and child health. We used data from 364 mother-child pairs in the MIREC study, a prospective pan-Canadian cohort. During pregnancy, we measured first trimester urinary arsenic concentrations, plasma folate biomarkers, and folic acid supplementation intake. At age 3 years, we evaluated twelve neurodevelopmental and anthropometric features. Using latent profile analysis and multinomial regression, we developed phenotypic profiles of child health, estimated covariate-adjusted associations between arsenic and these phenotypic profiles, and evaluated whether folate status modified these associations. We identified three phenotypic profiles of neurodevelopment and three of anthropometry, ranging from less to more optimal child health. Gestational arsenic was associated with decreased odds of optimal neurodevelopment. Maternal folate status did not modify associations of arsenic with neurodevelopmental phenotypic profiles, but gestational arsenic was associated with increased odds of excess adiposity among those who exceed recommendations for folic acid (>1000 μg/day). However, arsenic exposure was low and folate status was high. Gestational arsenic exposure may adversely impact child neurodevelopment and anthropometry, and maternal folate status may not modify these associations; however, future work should examine these associations in more arsenic-exposed or lower folate-status populations.

Environmental and occupational exposure of metals and female reproductive health

Untainted environment promotes health, but the last few decades experienced steep upsurge in environmental contaminants posing detrimental physiological impact. The responsible factors mainly include the exponential growth of human population, havoc rise in industrialization, poorly planned urbanization, and slapdash environment management. Environmental degradation can increase the likelihood of human exposure to heavy metals, resulting in health consequences such as reproductive problems. As a result, research into metal-induced causes of reproductive impairment at the genetic, epigenetic, and biochemical levels must be strengthened further. These metals impact upon the female reproduction at all strata of its regulation and functions, be it development, maturation, or endocrine functions, and are linked to an increase in the causes of infertility in women. Chronic exposures to the heavy metals may lead to breast cancer, endometriosis, endometrial cancer, menstrual disorders, and spontaneous abortions, as well as pre-term deliveries, stillbirths. For example, endometriosis, endometrial cancer, and spontaneous abortions are all caused by the metalloestrogen cadmium (Cd); lead (Pb) levels over a certain threshold can cause spontaneous abortion and have a teratogenic impact; toxic amounts of mercury (Hg) have an influence on the menstrual cycle, which can lead to infertility. Impact of environmental exposure to heavy metals on female fertility is therefore a well-known fact. Thus, the underlying mechanisms must be explained and periodically updated, given the growing evidence on the influence of increasing environmental heavy metal load on female fertility. The purpose of this review is to give a concise overview of how heavy metal affects female reproductive health.

Developmental programming of macrophages by early life adversity

Macrophages are central elements of all organs, where they have a multitude of physiological and pathological functions. The first macrophages are produced during fetal development, and most adult organs retain populations of fetal-derived macrophages that self-maintain without major input of hematopoietic stem cell-derived monocytes. Their developmental origins make macrophages highly susceptible to environmental perturbations experienced in early life, in particular the fetal period. It is now well recognized that such adverse developmental conditions contribute to a wide range of diseases later in life. This chapter explores the notion that macrophages are key targets of environmental adversities during development, and mediators of their long-term impact on health and disease. We first briefly summarize our current understanding of macrophage ontogeny and their biology in tissues and consider potential mechanisms by which environmental stressors may mediate fetal programming. We then review evidence for programming of macrophages by adversities ranging from maternal immune activation and diet to environmental pollutants and toxins, which have disease relevance for different organ systems. Throughout this chapter, we contemplate appropriate experimental strategies to study macrophage programming. We conclude by discussing how our current knowledge of macrophage programming could be conceptualized, and finally highlight open questions in the field and approaches to address them.

Exposure to metal mixture and growth indicators at 4-5 years. A study in the INMA-Asturias cohort

BACKGROUND

Exposure to toxic and non-toxic metals impacts childhood growth and development, but limited data exists on exposure to metal mixtures. Here, we investigated the effects of exposure to individual metals and a mixture of barium, cadmium, cobalt, lead, molybdenum, zinc, and arsenic on growth indicators in children 4-5 years of age.

METHODS

We used urine metal concentrations as biomarkers of exposure in 328 children enrolled in the Spanish INMA-Asturias cohort. Anthropometric measurements (arm, head, and waist circumferences, standing height, and body mass index) and parental sociodemographic variables were collected through face-to-face interviews by trained study staff. Linear regressions were used to estimate the independent effects and were adjusted for each metal in the mixture. We applied Bayesian kernel machine regression to examine non-linear associations and potential interactions.

RESULTS

In linear regression, urinary levels of cadmium were associated with reduced arm circumference (β_adjusted = -0.44, 95% confidence interval [CI]: -0.73, -0.15), waist circumference (β_adjusted = -1.29, 95% CI: -2.10, -0.48), and standing height (β_adjusted = -1.09, 95% CI: -1.82, -0.35). Lead and cobalt concentrations were associated with reduced standing height (β_adjusted = -0.64, 95% CI: -1.20, -0.07) and smaller head circumference (β_adjusted = -0.29, 95% CI: -0.49, -0.09), respectively. However, molybdenum was positively associated with head circumference (β_adjusted = 0.22, 95% CI: 0.01, 0.43). BKMR analyses showed strong linear negative associations of cadmium with arm and head circumference and standing height. BKMR analyses also found lead and cobalt in the metal mixture were related to reduce standing height and head circumference, and consistently found molybdenum was related to increased head circumference.

CONCLUSION

Our findings suggest that exposure to metal mixtures impacts growth indicators in children.

Aquoeus Extracts of Daucus Carota (Linn) Protected the Postnatal Developing Cerebellum of Wistar Rats Against Arsenic-Induced Oxidative Stress

The neuroprotective effects of the aqueous extract of Daucus carota (Dc) tuber against arsenic-induced oxidative damage on the developing cerebellum of Wistar rats were studied. Twenty-five pregnant rats (110-200g) were divided into five groups (n=5) - control received distilled water; Arsenic (As); Dc (200mg/kg); Dc (200mg/kg) +As; Vitamin C (Vc) (100mg/kg) +As. The pregnant rats in all the groups were treated orally from the first day of pregnancy to postnatal day 21. The Dc extract and Vc were administered one hour before the administration of As. Body weight of the pups on days 1, 7, 14, 21 and 28 were recorded, while neurobehavioural (forelimb grip strength and negative geotaxis) tests were done on day 21 pups. The rats were sacrificed and cerebellar tissues were collected for oxidative stress, histological (H and E), and immunohistochemical studies. Decreased forelimb grip strength, increased lipid peroxidation and decreased glutathione, glutathione peroxidase, catalase and superoxide dismutase was observed in the As group compared with the control and other treated groups. Histologically, the cerebellar cortex of the As pups showed persistent external granular layer (EGL) on postnatal day 21, reduced thickness of the molecular layer (ML) on postnatal day 28, pyknotic and depleted Purkinje cells compared with the control and other treated rats. Immunohistochemical evaluations of the cerebellar cortex showed astroliosis in the As-treated group on day 21 pups compared with the control and other treated groups.  Aqueous extracts of Daucus carota and Vitamin C reversed the toxicity caused by arsenic. From the results of the study, arsenic-induced oxidative stress with morphological alterations in the perinatal developing rat cerebellum. Extracts of Daucus carota exhibited antioxidant activity as such may be a potential neuroprotective agent.

Is living in a region with high groundwater arsenic contamination associated with adverse reproductive health outcomes? An analysis using nationally representative data from India

BACKGROUND

Exposure to groundwater arsenic via drinking water is common in certain geographies, such as parts of India, and causes a range of negative health effects, potentially including adverse reproductive health outcomes.

METHODS

We conducted an ecological analysis of self-reported rates of stillbirth, recurrent pregnancy loss, and infertility in relation to groundwater arsenic levels in India. We used a gridded, modeled dataset of the probability of groundwater arsenic exceeding 10 μg/L (World Health Organization drinking water limit) to calculate mean probabilities at the district level (n = 599 districts). A spatial integration approach was used to merge these estimates with the third India District-Level Health Survey (DLHS-3) conducted in 2007-08 (n = 643,944 women of reproductive age). Maps of district level arsenic levels and rates of each of the three outcomes were created to visualize the patterns across India. To adjust for significant spatial autocorrelation, spatial error models were fit.

FINDINGS

District-level analysis showed that the average level of stillbirth was 4.3%, recurrent pregnancy loss was 3.3%, and infertility was 8.1%. The average district-level probability of groundwater arsenic levels exceeding 10 μg/L was 42%. After adjustment for sociodemographic factors, and accounting for spatial dependence, at the district level, for each percentage point increase in predicted arsenic levels exceeding 10 μg/L increased, the rates of stillbirths was 4.5% higher (95% confidence interval (CI) 2.4-6.6, p < 0.0001), the rates of RPL are 4.2% higher (95% CI 2.5-5.9, p < 0.0001), and the rates of infertility are 4.4% higher (95% CI 1.2-7.7, p=<0.0001).).

CONCLUSIONS

While arsenic exposure has been implicated with a range of adverse health outcomes, this is one of the first population-level studies to document an association between arsenic and three adverse reproductive pregnancy outcomes. The high levels of spatial correlation suggest that further and targeted efforts to mitigate arsenic in groundwater are needed.

Provision of folic acid for reducing arsenic toxicity in arsenic-exposed children and adults

BACKGROUND

Arsenic is a common environmental toxin. Exposure to arsenic (particularly its inorganic form) through contaminated food and drinking water is an important public health burden worldwide, and is associated with increased risk of neurotoxicity, congenital anomalies, cancer, and adverse neurodevelopment in children. Arsenic is excreted following methylation reactions, which are mediated by folate. Provision of folate through folic acid supplements could facilitate arsenic methylation and excretion, thereby reducing arsenic toxicity.

OBJECTIVES

To assess the effects of provision of folic acid (through fortified foods or supplements), alone or in combination with other nutrients, in lessening the burden of arsenic-related health outcomes and reducing arsenic toxicity in arsenic-exposed populations.

SEARCH METHODS

In September 2020, we searched CENTRAL, MEDLINE, Embase, 10 other international databases, nine regional databases, and two trials registers.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs comparing the provision of folic acid (at any dose or duration), alone or in combination with other nutrients or nutrient supplements, with no intervention, placebo, unfortified food, or the same nutrient or supplements without folic acid, in arsenic-exposed populations of all ages and genders.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included two RCTs with 822 adults exposed to arsenic-contaminated drinking water in Bangladesh. The RCTs compared 400 µg/d (FA400) or 800 µg/d (FA800) folic acid supplements, given for 12 or 24 weeks, with placebo. One RCT, a multi-armed trial, compared FA400 plus creatine (3 g/d) to creatine alone. We judged both RCTs at low risk of bias in all domains. Due to differences in co-intervention, arsenic exposure, and participants' nutritional status, we could not conduct meta-analyses, and therefore, provide a narrative description of the data. Neither RCT reported on cancer, all-cause mortality, neurocognitive function, or congenital anomalies. Folic acid supplements alone versus placebo Blood arsenic. In arsenic-exposed individuals, FA likely reduces blood arsenic concentrations compared to placebo (2 studies, 536 participants; moderate-certainty evidence). For folate-deficient and folate-replete participants who received arsenic-removal water filters as a co-intervention, FA800 reduced blood arsenic levels more than placebo (percentage change (%change) in geometric mean (GM) FA800 -17.8%, 95% confidence intervals (CI) -25.0 to -9.8; placebo GM -9.5%, 95% CI -16.5 to -1.8; 1 study, 406 participants). In one study with 130 participants with low baseline plasma folate, FA400 reduced total blood arsenic (%change FA400 mean (M) -13.62%, standard error (SE) ± 2.87; placebo M -2.49%, SE ± 3.25), and monomethylarsonic acid (MMA) concentrations (%change FA400 M -22.24%, SE ± 2.86; placebo M -1.24%, SE ± 3.59) more than placebo. Inorganic arsenic (InAs) concentrations reduced in both groups (%change FA400 M -18.54%, SE ± 3.60; placebo M -10.61%, SE ± 3.38). There was little to no change in dimethylarsinic acid (DMA) in either group. Urinary arsenic. In arsenic-exposed individuals, FA likely reduces the proportion of total urinary arsenic excreted as InAs (%InAs) and MMA (%MMA) and increases the proportion excreted as DMA (%DMA) to a greater extent than placebo (2 studies, 546 participants; moderate-certainty evidence), suggesting that FA enhances arsenic methylation. In a mixed folate-deficient and folate-replete population (1 study, 352 participants) receiving arsenic-removal water filters as a co-intervention, groups receiving FA had a greater decrease in %InAs (within-person change FA400 M -0.09%, 95% CI -0.17 to -0.01; FA800 M -0.14%, 95% CI -0.21 to -0.06; placebo M 0.05%, 95% CI 0.00 to 0.10), a greater decrease in %MMA (within-person change FA400 M -1.80%, 95% CI -2.53 to -1.07; FA800 M -2.60%, 95% CI -3.35 to -1.85; placebo M 0.15%, 95% CI -0.37 to 0.68), and a greater increase in %DMA (within-person change FA400 M 3.25%, 95% CI 1.81 to 4.68; FA800 M 4.57%, 95% CI 3.20 to 5.95; placebo M -1.17%, 95% CI -2.18 to -0.17), compared to placebo. In 194 participants with low baseline plasma folate, FA reduced %InAs (%change FA400 M -0.31%, SE ± 0.04; placebo M -0.13%, SE ± 0.04) and %MMA (%change FA400 M -2.6%, SE ± 0.37; placebo M -0.71%, SE ± 0.43), and increased %DMA (%change FA400 M 5.9%, SE ± 0.82; placebo M 2.14%, SE ± 0.71), more than placebo. Plasma homocysteine: In arsenic-exposed individuals, FA400 likely reduces homocysteine concentrations to a greater extent than placebo (2 studies, 448 participants; moderate-certainty evidence), in the mixed folate-deficient and folate-replete population receiving arsenic-removal water filters as a co-intervention (%change in GM FA400 -23.4%, 95% CI -27.1 to -19.5; placebo -1.3%, 95% CI -5.3 to 3.1; 1 study, 254 participants), and participants with low baseline plasma folate (within-person change FA400 M -3.06 µmol/L, SE ± 3.51; placebo M -0.05 µmol/L, SE ± 4.31; 1 study, 194 participants). FA supplements plus other nutrient supplements versus nutrient supplements alone In arsenic-exposed individuals who received arsenic-removal water filters as a co-intervention, FA400 plus creatine may reduce blood arsenic concentrations more than creatine alone (%change in GM FA400 + creatine -14%, 95% CI -22.2 to -5.0; creatine -7.0%, 95% CI -14.8 to 1.5; 1 study, 204 participants; low-certainty evidence); may not change urinary arsenic methylation indices (FA400 + creatine: %InAs M 13.2%, SE ± 7.0; %MMA M 10.8, SE ± 4.1; %DMA M 76, SE ± 7.8; creatine: %InAs M 14.8, SE ± 5.5; %MMA M 12.8, SE ± 4.0; %DMA M 72.4, SE ±7.6; 1 study, 190 participants; low-certainty evidence); and may reduce homocysteine concentrations to a greater extent (%change in GM FA400 + creatinine -21%, 95% CI -25.2 to -16.4; creatine -4.3%, 95% CI -9.0 to 0.7; 1 study, 204 participants; low-certainty evidence) than creatine alone.

AUTHORS' CONCLUSIONS

There is moderate-certainty evidence that FA supplements may benefit blood arsenic concentration, urinary arsenic methylation profiles, and plasma homocysteine concentration versus placebo. There is low-certainty evidence that FA supplements plus other nutrients may benefit blood arsenic and plasma homocysteine concentrations versus nutrients alone. No studies reported on cancer, all-cause mortality, neurocognitive function, or congenital anomalies. Given the limited number of RCTs, more studies conducted in diverse settings are needed to assess the effects of FA on arsenic-related health outcomes and arsenic toxicity in arsenic-exposed adults and children.

A cohort study of the association between prenatal arsenic exposure and age at menarche in a rural area, Bangladesh

BACKGROUND

Millions of individuals worldwide, particularly in Bangladesh, are exposed to arsenic, mainly through drinking water from tube wells. Arsenic is a reproductive toxicant, but there is limited knowledge of whether it influences pubertal development.

OBJECTIVES

We evaluated the association between prenatal arsenic exposure and age at menarche.

METHODS

This prospective study was based on data from two studies conducted in Matlab, Bangladesh-the Maternal and Infant Nutrition Interventions in Matlab (MINIMat) trial and the Health Consequences of Arsenic in Matlab (AsMat) study. We included 809 MINIMat girls who participated in assessing age at menarche from July 2016 to June 2017 and had prenatal arsenic exposure data through the AsMat study via measurements in tube well water used by the mothers during pregnancy. The exposure was categorized into <10, 10-49, 50-99, 100-199, and ≥200 µg/L. We used Kaplan-Meier and Cox proportional hazards analyses with adjustment for potential confounders to evaluate the association between arsenic exposure and age at menarche. The results were presented by adjusted hazards ratio (aHR) with a 95% confidence interval (CI).

RESULTS

The median arsenic concentration in tube well water consumed by pregnant women was 80 µg/L (interquartile range 2-262 µg/L), and 55% drank water with concentrations above Bangladesh's acceptable value of 50 µg/L. The median age at menarche was 13.0 years. The unadjusted analysis revealed 3.2 months delay in menarche for girls exposed to arsenic concentrations ≥200 µg/L compared with the girl exposed to arsenic concentrations <10 µg/L. Girls exposed to the same higher arsenic concentrations were 23% (aHR 0.77, 95% CI: 0.63-0.95) less likely to have reached menarche than girls exposed to low arsenic concentrations.

CONCLUSIONS

Increased levels of prenatal arsenic exposure were associated with older age at menarche. This delay may indicate endocrine disruptions that could potentially result in adverse health consequences in later life. This finding, along with other severe adverse health reinforces the need for arsenic mitigation at the population level.

Molecular perspective concerning fluoride and arsenic mediated disorders on epididymal maturation of spermatozoa: A concise review

Epididymis is a complex tubular structure of male reproductive system where spermatozoa undergo maturation and gain the fertilizing ability. Epididymal pseudostratified columnar epithelium with different cell types play imperative role by their secretory properties and enrich the luminal microenvironment necessary for achieving spermatozoal motility. During epididymal transit several secretory proteins like P26h, SPAG11, HSPD1 and many others are deposited on spermatozoal surface. At the same time spermatozoal proteins are also modified in this intraluminal milieu, which include cyritestin, fertilin, CE9 and others. Natural and anthropogenic activities disclose various environmental pollutants which affect different physiological systems of animals and human being. Likewise, reproductive system is also being affected. Fluoride causes structural alterations of caput and cauda segments of epididymis. Redox homeostasis and functional integrity are also altered due to diminished activities of SOD1, GR, Crisp2, Lrp2 and other important proteins. On the contrary arsenic affects mostly on cauda segment. Redox imbalance and functional amendment in epididymis have been observed with arsenic revelation as evidenced by altered genomic appearance of SOD, GST, catalase, Ddx3Y, VEGF and VEGFR2. This review is dealt with structure-function interplay in normal epididymal spermatozoal maturation along with subsequent complications developed under fluoride and arsenic toxicities.

Low‑Level Environmental Heavy Metals are Associated with Obesity Among Postmenopausal Women in a Southern State

Both arsenic and cadmium are reported to be toxic to humans. The use of saliva as a biomarker of low-level exposures to these elements has not been adequately explored, and the putative relationship between exposure and obesity is unclear. This cross-sectional study aims to investigate the relationship between salivary arsenic and cadmium concentrations and their association with obesity. Arsenic and cadmium concentrations were analyzed in human saliva samples by Inductively Coupled Plasma-Mass Spectrometry on 270 randomly selected women who participated in the Arkansas Rural Community Health Study. Multivariable logistic regression was performed to evaluate the association between heavy metal concentrations and obesity. Stratified logistic regression was performed based on menopausal status. Generalized linear models were used to evaluate weight gain velocity. Significant positive associations were observed in postmenopausal women for both arsenic (OR = 4.43, 95% CI 1.91-10.28) and cadmium (OR = 2.72, 95% CI 1.23-5.99) concentrations, as well as significant trends among tertiles (p < 0.01 and p = 0.01, respectively). No relationship with obesity was evident among premenopausal women for either metal. A dose-response relationship was observed between increasing weight gain velocity and increasing metal concentrations. At concentrations well below governmental and industrial standards for acute toxicity, significant associations between obesity and concentration of these heavy metals are evident. The rate at which individuals gain weight is affected by metal concentrations and may play a role in the rapid increase in weight in postmenopausal women. These results might explain, in part, the missing variability in the increasing obesity pandemic in certain population exposed to these environmental toxicants.

Exposure to toxic metals and per- and polyfluoroalkyl substances and the risk of preeclampsia and preterm birth in the United States: a review

Preeclampsia and preterm birth are among the most common pregnancy complications and are the leading causes of maternal and fetal morbidity and mortality in the United States. Adverse pregnancy outcomes are multifactorial in nature and increasing evidence suggests that the pathophysiology behind preterm birth and preeclampsia may be similar-specifically, both of these disorders may involve abnormalities in placental vasculature. A growing body of literature supports that exposure to environmental contaminants in the air, water, soil, and consumer and household products serves as a key factor influencing the development of adverse pregnancy outcomes. In pregnant women, toxic metals have been detected in urine, peripheral blood, nail clippings, and amniotic fluid. The placenta serves as a "gatekeeper" between maternal and fetal exposures, because it can reduce or enhance fetal exposure to various toxicants. Proposed mechanisms underlying toxicant-mediated damage include disrupted placental vasculogenesis, an up-regulated proinflammatory state, oxidative stressors contributing to prostaglandin production and consequent cervical ripening, uterine contractions, and ruptured membranes and epigenetic changes that contribute to disrupted regulation of endocrine and immune system signaling. The objective of this review is to provide an overview of studies examining the relationships between environmental contaminants in the US setting, specifically inorganic (eg, cadmium, arsenic, lead, and mercury) and organic (eg, per- and polyfluoroalkyl substances) toxicants, and the development of preeclampsia and preterm birth among women in the United States.

Carcinogenic and non-carcinogenic health risk of arsenic ingestion via drinking water in Langat River Basin, Malaysia

The prolonged persistence of toxic arsenic (As) in environment is due to its non-biodegradable characteristic. Meanwhile, several studies have reported higher concentrations of As in Langat River. However, it is the first study in Langat River Basin, Malaysia, that As concentrations in drinking water supply chain were determined simultaneously to predict the health risks of As ingestion. Water samples collected in 2015 from the four stages of drinking water supply chain were analysed for As concentration by inductively coupled plasma mass spectrometry. Determined As concentrations along with the time series data (2004-2015) were significantly within the maximum limit 0.01 mg/L of drinking water quality standard set by World Health Organization. The predicted As concentration by auto-regression moving average was 3.45E-03 mg/L in 2020 at 95% level based on time series data including climatic control variables. Long-term As ingestion via household filtration water at Langat Basin showed no potential lifetime cancer risk (LCR) 9.7E-06 (t = 6.68; p = 3.37E-08) as well as non-carcinogenic hazard quotient (HQ) 4.8E-02 (t = 6.68; p = 3.37E-08) risk at 95% level. However, the changing landscape, ex-mining ponds and extensive use of pesticides for palm oil plantation at Langat Basin are considered as the major sources of increased As concentration in Langat River. Therefore, a two-layer water filtration system at Langat Basin should be introduced to accelerate the achievement of sustainable development goal of getting safe drinking water supply.

Prenatal Environmental Metal Exposure and Preterm Birth: A Scoping Review

Preterm birth (PTB) and its complications are the leading causes of under-five year old child deaths, accounting worldwide for an estimated one million deaths annually. The etiology of PTB is complex and multifactorial. Exposures to environmental metals or metalloids are pervasive and prenatal exposures to them are considered important in the etiology of PTB. We conducted a scoping review to determine the extent of prenatal exposures to four metals/metalloids (lead, mercury, cadmium and arsenic) and their association with PTB. We reviewed original research studies published in PubMed, Embase, the Cochrane Library, Scopus, POPLINE and the WHO regional indexes from 2000 to 2019; 36 articles were retained for full text review. We documented a higher incidence of PTB with lead and cadmium exposures. The findings for mercury and arsenic exposures were inconclusive. Metal-induced oxidative stress in the placenta, epigenetic modification, inflammation, and endocrine disruptions are the most common pathways through which heavy metals and metalloids affect placental functions leading to PTB. Most of the studies were from the high-income countries, reflecting the need for additional data from low-middle-income countries, where PTB rates are higher and prenatal exposure to metals are likely to be just as high, if not higher.

Impact of prenatal arsenic exposure on the testes and epididymides of prepubertal rats

Arsenic is a pollutant widely found in the environment due to natural and anthropogenic sources. Exposure to arsenic forms in drinking water has been related with male reproductive dysfunctions in humans and experimental animals at adult age. However, the impact of this pollutant on postnatal reproductive development of male offspring exposed in utero to arsenic is still unknown. Therefore, this study aimed to investigate the effects of prenatal arsenic exposure on the postnatal development of the testes and epididymides of rats, during prepuberty. For this purpose, pregnant female Wistar rats were provided drinking water containing 0 or 10 mg/L sodium arsenite (AsNaO₂) from gestational day 1 (GD 1) until GD 21 and the male offspring was evaluated in different periods of prepuberty. Our results showed that prenatal arsenic exposure affected the initial sexual development of male pups, reducing their body weight and relative anogenital distance at postnatal day 1. At different periods of prepuberty, male pups from arsenic exposed dams showed a reduction of body and reproductive organs weights, testosterone levels and testis morphometric parameters. Moreover, these pups presented changes in the expression of SOD1, SOD2, CAT and GSTK1 genes and in the activity of superoxide dismutase, catalase and glutathione s-transferase in the testes and epididymides during prepuberty. Taken together, our results show that prenatal arsenic exposure provoked reproductive disorders in prepubertal male rats, probably due to reproductive reprograming and oxidative stress induced by this pollutant.

Elevated non-essential metals and the disordered metabolism of essential metals are associated to abnormal pregnancy with spontaneous abortion

Spontaneous abortion is a considerable threat to the physiology and mental health of the mother. The etiology of spontaneous abortion is multifactorial with complicated mechanisms, of which overexposure to non-essential metals (especially heavy metals) has been proposed to be associated with adverse birth outcomes. However, significant knowledge gaps remain to be filled in, such as the deleterious profile of non-essential metals and their interplay with essential metals in abnormal pregnancy. Under this setting, we aimed to address these challenges by conducting a cross-sectional study on 56 patients with spontaneous abortion in the 1^st trimester, by comparing to 55 healthy pregnant women in 1^st the trimester and 41 non-pregnant healthy women. Overexposure to a few non-essential metals, such as arsenic (As), antimony (Sb) and bismuth (Bi), was found in patients with spontaneous abortion, and likewise, some essential elements, such as magnesium (Mg), copper (Cu), vanadium (V), strontium (Sr) and tin (Sn), were also found to be elevated under spontaneous abortion. Further evidence of abnormal pregnancy was induced by a reduced level of internal hormones necessary for normal gestation, such as estradiol (E2) and progesterone (PRGE) in women with spontaneous abortion. Lactate dehydrogenase (LDH) and thyroid-stimulating hormone (TSH) levels were slightly increased in patients with spontaneous abortion. Comprehensive correlation analyses were carried out to identify the crucial factors that result in abortion. Our data stratified the important variables in decreasing order: PRGE, As, Mg, Sb, Sr, Sn, Bi and pregnant times in the progress of spontaneous abortion. Moreover, labyrinthine associations were uncovered between PRGE, non-essential metals and essential elements in causing spontaneous abortion. Therefore, our combined data unveiled the likely synergistic implications of elevated non-essential metals and the disordered metabolism of essential metals in abnormal pregnancy.

Environmental Exposures in the Etiology of Abortion: Placental Toxic and Trace Element Levels

PURPOSE

Intensive research has been conducted on the effects of toxic and trace elements on pregnancy. Previous studies indicated a possible relationship between placental levels of these elements and first-trimester abortion; however, their effects on the further gestational weeks are not clear. This study aimed to investigate the effect of changes in the levels of placental trace and toxic elements on second-trimester abortion.

METHODS

The patient group consisted of 30 women with missed abortion. The control group comprised 60 healthy term and singleton pregnant women who gave birth. Placental samples were obtained from the patients and the healthy controls, and the concentrations of placental elements were measured using inductively coupled plasma mass spectrometry.

RESULTS

In the abortion group, placental arsenic, cadmium, mercury, lead, antimony, tin, cobalt, manganese, and selenium levels were significantly higher than those of the control group (p<0.05). Antimony was determined as an independent predictor with an odds ratio of 6.1 in toxic elements (p=0.025), and selenium was determined as an independent predictor with an odds ratio of 2.3 in trace elements (p=0.015).

CONCLUSION

The changes in trace element and toxic element levels, especially an increase in antimony and selenium, in placental tissue due to environmental exposure may play an important role in second-trimester abortion.

In vitro model insights into the role of human gut microbiota on arsenic bioaccessibility and its speciation in soils

The bioaccessibility of arsenic and its speciation are two important factors in assessing human health risks exposure to contaminated soils. However, the effects of human gut microbiota on arsenic bioaccessibility and its speciation are not well characterized. In this study, an improved in vitro model was utilized to investigate the bioaccessibility of arsenic in the digestive tract and the role of human gut microbiota in the regulation of arsenic speciation. For all soils, arsenic bioaccessibility from the combined in vitro model showed that it was <40% in the gastric, small intestinal and colon phases. This finding demonstrated that the common bioaccessibility approach assuming 100% bioaccessibility would overestimate the human health risks posed by contaminated soils. Further to this, the study showed that arsenic bioaccessibility was 22% higher in the active colon phase than that in the sterile colon phase indicating that human colon microorganisms could induce arsenic release from the solid phase. Only inorganic arsenic was detected in the gastric and small intestinal phases, with arsenate [As(V)] being the dominant arsenic species (74%-87% of total arsenic). Arsenic speciation was significantly altered by the active colon microbiota, which resulted in the formation of methylated arsenic species, including monomethylarsonic acid [MMA(V)] and dimethylarsinic acid [DMA(V)] with low toxicity, and a highly toxic arsenic species monomethylarsonous acid [MMA(III)]. Additionally, a high level of monomethylmonothioarsonic acid [MMMTA(V)] (up to 17% of total arsenic in the extraction solution) with unknown toxicological properties was also detected in the active colon phase. The formation of various organic arsenic species demonstrated that human colon microorganisms could actively metabolize inorganic arsenic into methylated arsenicals and methylated thioarsenicals. Such transformation should be considered when assessing the human health risks associated with oral exposure to soil.

Maternal exposure to arsenic and mercury and associated risk of adverse birth outcomes in small-scale gold mining communities in Northern Tanzania

BACKGROUND

Exposure to arsenic and mercury in artisanal and small-scale gold mining (ASGM) communities is an issue that predominantly affects low and middle-income countries. Large epidemiology studies in these communities are rare, and the impact of such exposures on reproductive outcomes are not well understood.

OBJECTIVE

To examine associations between prenatal maternal arsenic and mercury exposure and birth outcomes in both ASGM and non-ASGM communities in Northern Tanzania.

METHODS

This longitudinal prospective study included 961 women (ASGM = 788, non-ASGM = 173) of the original cohort of 1056 who were followed until a pregnancy outcome was registered. Maternal spot urine samples and dried blood spots were used to measure total arsenic (T-As) and total mercury (T-Hg) in the second trimester of pregnancy. Data on adverse birth outcomes were collected in 5 categories: spontaneous abortion, stillbirth, preterm birth, low birth weight, and visible congenital anomalies. Mann-Whitney U-tests were used to test for differences between median T-As and T-Hg by area of residence. Logistic regression models were used to estimate the odds of stillbirth and visible congenital anomalies given maternal T-As and T-Hg levels. Modified Poisson regressions were used to estimate relative risk ratios between maternal T-As and T-Hg levels and composite adverse birth outcome, spontaneous abortion, low birth weight, and preterm birth.

RESULTS

Statistically significant differences were found in median T-As (9.6 vs. 6.3 µg/L, Mann-Whitney U-tests, Z = -3.50, p < 0.001) and median T-Hg blood concentrations (1.2 vs. 0.70 µg/L, Z = -9.88, p-value < 0.001) between women living in ASGM and non-ASGM areas respectively. In ASGM areas, the adjusted relative risk (aRR) of a composite adverse birth outcome increased with increasing T-As (aRR 1.23, 95%CI: 1.14-1.33, p < 0.0001) and T-Hg (aRR 1.17, 95%CI: 1.1-1.25, p < 0.0001) exposure. Spontaneous abortion (aRR 1.53, 95%CI: 1.28-1.83), stillbirth (adjusted odds ratio (aOR) 1.97, 95%CI: 1.45-2.66) and preterm birth (1.17, 95%CI: 1.01-1.36) were significantly associated with elevated T-As, whereas elevated T-Hg was significantly associated with stillbirth (aOR 2.49, 95%CI: 1.88-3.29) and visible congenital anomalies (aOR 2.24, 95%CI: 1.3-3.87).

CONCLUSION

Over half (54.7%) of women in ASGM areas of Northern Tanzania had adverse birth outcomes and the risk of adverse birth outcomes was significantly associated with increased prenatal exposure to arsenic and mercury.

Suburban areas in flames: Dispersion of potentially toxic elements from burned vegetation and buildings. Estimation of the associated ecological and human health risk

The results of the assessment of burned residential and wildland areas associated with the July 2018 western Attica wildfire are summarised. The dispersion of major and trace elements in a fire impacted suburban landscape which is adjacent in the north with a Natura 2000 area is evaluated. The dataset includes 35 elements and 27 sampling sites spatially distributed in wildland and residential areas. Field observations and a macroscopic method were applied for investigating the wildfire severity. Statistical and spatial analysis tools were used for data treatment. Major and trace element contents were compared to levels and criteria provided by the United States Environmental Protection Agency, Canadian Council of Ministers of the Environment and Australian Department of Environment and Conservation. Aluminum, As, Co, Fe, Mn, Ni, Sb and Zn concentrations observed in wildfire ash pose potential risk to human health. Median ash concentrations for Al, As, B, Ba, Cd, Cu, Fe, Mn, Ni, Pb, S, Sb, and Zn exceeds the plant-avian-mammalian screening levels in wildland and residential areas. Geogenic or anthropogenic origin of the elements is discussed. The associated health risk on human health and terrestrial ecological receptors (plant, avian, mammalian) is assessed.

Assessment of carcinogenic and toxic substances in 'Insunko' herb

There has emerged a herb in Zambia called 'insunko' which has unknown chemical composition. The use of 'insunko' herb with unknown chemical composition has brought mixed feelings among many Zambians. This study, therefore, aimed to assess the toxic and carcinogenic substances in'insunko' herb. 'Insunko' herb was purchased from Chipata, Lusaka, Mpika, Mwense, Kitwe, and Solwezi. 5 samples were collected from each of these districts and were thoroughly mixed to give 6 consolidated samples (n = 6). Nicotine and, nitrosamines were analysed using UV spectrometer lambda 35 Perkin Elmer while trace metals were analysed using ICP-MS Inductively Coupled Plasma Mass Spectroscopy (Agilent Technologies, Santa Clara, CA, USA). Nicotine, nitrosamines, and trace metals were detected in high concentrations. The concentrations ranged from 3.87 to 9.83 mg/kg for nitrosamines and 10.94-34.01 mg/kg for nicotine. Hazard Indexes for arsenic, cadmium, chromium, manganese, and copper were greater than one (HI > 1). 'Insunko' herb is a potentially toxic and carcinogenic substance because it contains toxic and carcinogenic constituents in high concentrations. These toxic and carcinogenic constituents have been confirmed to cause gastrointestinal disorders, cancers, degenerative, cardiovascular, hematopoietic, neurologic and cognitive problems as well as male infertility.

Arsenic: Geochemical distribution and age-related health risk in Italy

This study is the first attempt to evaluate occurrence, distribution and potential health impacts of As at a national scale in Italy. In various environmental matrices, As geochemical distribution was investigated and carcinogenic and non-carcinogenic risks were assessed with respect to different exposure routes and age groups. Both deterministic and probabilistic methods were used to determine the health risks. Geochemical mapping at a sub-continental scale provided a useful tool to spatially represent As concentration and the critical areas posing a health threat to inhabitants. The results show that significant As concentrations in tap water and soil (up to 27.20 μg/l and 62.20 mg/kg, respectively) are mainly governed by geological features. In the central parts of Italy, where alkaline volcanic materials and consequently high levels of As occur, the residents are prone to health issues. Daily exposure to As in tap water is unparalleled playing an important role in the potential cancer and non-cancer risks. The Incremental Lifetime Cancer Risk for skin cancer and also lung and bladder cancer associated with tap water ingestion interestingly shows that (i) almost 80% of the computed values fall above the internationally accepted benchmark value of 1 × 10^-5; (ii) majority of the data exceed the acceptable risk proposed by most jurisdictions, such as that of Italian law (1 × 10^-6). Further, geographical variation of health risk highlights high carcinogenic and non-carcinogenic risk associated with water ingestion for those living in the northern Alps (including the city of Trento) and the central and southern Italy (including the capital Rome and the cities of Napoli and Catanzaro). According to the results, application of the probabilistic method which considers variability and uncertainty is preferred to the deterministic approach for risk assessment. The sensitivity analysis showed that As concentration in drinking water and exposure duration are the factors with the greatest impact on the outcome of risk assessment (for all age groups). The results of the current study may be a good starting point for authorities to urgently decide about the needed policy actions in order to prevent the adverse health effects and to reduce the human health risk due to As exposure.

Arsenic and smokeless tobacco exposure induces DNA damage and oxidative stress in reproductive organs of female Swiss albino mice

Arsenic contamination in the groundwater of Southern Assam, India is well-documented. A specific type of smokeless tobacco (sadagura, SG) is highly prevalent among the local population. Thus, the present study is aimed to evaluate the toxicological implications of arsenic and smokeless tobacco co-exposure on the reproductive health of female mice. The estrous cycle of experimental animals was monitored for 30 days. Histopathological studies and comet assay of ovarian and uterine tissues were performed after 30 days of exposure to SG and arsenic (sodium arsenite, SA). Oxidative stress was estimated biochemically by taking tissue glutathione, lipid peroxidation (LPO), and superoxide dismutase activity as endpoints. Our findings indicated a prolonged diestrus phase in the SG + L + SA group (p < 0.001). Histopathological study revealed abnormal tissue architecture in treated groups. Comet assay study showed that SG + SA exposure significantly induced DNA damage in test animals. The elevated LPO level in the SG + SA group indicated oxidative stress generation in the reproductive tissues. The present study suggests that female reproductive organs are vulnerable to SA and SG and oxidative stress generation may be the possible mechanism behind DNA damage, impaired follicular growth, atresia, and altered estrous cycle in the mice test system.

Effects of sanitation practices on adverse pregnancy outcomes in India: a conducive finding from recent Indian demographic health survey

Background

Several risk factors predisposing women and their live-borns to adverse outcomes during pregnancy have been documented. Little is known about sanitation being a factor contributing to adverse pregnancy outcomes in India. The role of sanitation in adverse pregnancy outcomes remains largely unexplored in the Indian context. This study is an attempt to bring the focus on sanitation as a factor in adverse pregnancy outcome. Along with the sanitation factors, few confounder variables have also been studied in order to understand the adverse pregnancy outcomes.

Methods

The study is based on the fourth round of National Family Health Survey (NFHS-IV) covering 26,972 married women in the age-group 15–49. The study variables include the mother’s age, Body Mass Index (BMI), education, anemia, and Antenatal care (ANC) visits during their last pregnancy. The household level variable includes place of residence, religion, caste, wealth index, access to toilet, type of toilet, availability of water within toilet premises, and facility of hand wash near the toilet. Children study variables include Low Birth Weight (LBW), the order of birth (Parity), and the death of the children of the women in the last 5 years. The target variable Adverse Pregnancy Outcome (APO) was constructed using children born with low birth weight or died during the last pregnancy.

Results

We calculated both adjusted as well as unadjusted odds ratios for a better understanding of the association between sanitation and adverse pregnancy outcomes. Findings from the study showed that women who did not have access to a toilet within the house had a higher risk of adverse pregnancy outcome. In the multivariable model, no association was observed for adverse pregnancy outcome among women who did not have access to toilet and women who used shared toilet. Teenage (15–19 years), uneducated, underweight and anemic mothers were more likely to face APO as compare to other mothers in similar characteristics group.

Conclusions

Our findings contribute to the decidedly less available literature on maternal sanitation behaviour and adverse pregnancy outcomes. Our results support that sanitation is a very significant aspect for women who are about to deliver a baby as there was an association between sanitation and adverse pregnancy outcome. Education on sanitation practices is the need of the hour as much as it needs to follow.

Reproductive disorders in female rats after prenatal exposure to sodium arsenite

Arsenic is a metalloid widely found in the environment in organic and inorganic forms. Exposure to inorganic arsenic forms via drinking water has been associated with an increased incidence of negative health effects, including reproductive disorders and dysfunction of the endocrine system. However, the impact of arsenic exposure on female reproductive development is still unclear. Therefore, in the present study, we evaluated the effects of prenatal exposure to arsenic on the initial sexual development and puberty onset, and in the morphology of the female reproductive organs, estrous cycle regularity and fertility parameters during adulthood. To do that, pregnant female Wistar rats were exposed to 10 mg/L sodium arsenite via drinking water from gestational day (GD) 1 until GD 21 and the female offspring was evaluated in different postnatal days. Our results showed that prenatal arsenic exposure induced a decrease of litter weight and morphological masculinization in females at postnatal day 1. Moreover, these females had a delay in the age of puberty onset and alteration in estrous cycle number and length. During adulthood, females from the sodium arsenite group showed an increase in endometrium, myometrium and perimetrium areas, and an imbalance in uterine antioxidant enzyme activity. These animals also presented an increase in post-implantation loss and reabsorption number, leading to reduced viable fetus number. In conclusion, prenatal arsenic exposure in rats was able to promote female masculinization, alter sexual development and impair reproductive performance.

Biochemical investigation of association of arsenic exposure with risk factors of diabetes mellitus in Pakistani population and its validation in animal model

Arsenic is one of the naturally occurring heavy metal that has been reported to cause damaging effects on different body organs. This study was aimed to determine the arsenic level in different water sources and investigate the effect of arsenic exposure on risk factors of diabetes mellitus (DM) in human participants and experimental animals. We recruited 150 participants to investigate the arsenic exposure in their urine and from drinking water. We found that males contained significantly higher (P < 0.001) concentrations of urinary arsenic as compared with that of their female counterparts. Similarly, urinary arsenic concentration was high and showed significant association in the age of ≥ 60 years (P < 0.05), illiterate (P < 0.001), smokers (P < 0.0001), and diabetic (P < 0.0001) participants. Moreover, urinary arsenic exposure was also associated with higher levels of fasting (P < 0.001) and random blood glucose (P < 0.001), HbA1c (P < 0.001), AST, ALT, MDA, IL-6, CRP, blood urea nitrogen, and creatinine in arsenic-exposed diabetics as compared with that of unexposed diabetics. Further, we also exposed the white albino rats with arsenic in drinking water for 30 days and their blood glucose was measured at 15th and 30th days of treatment that was significantly higher (P < 0.001) in arsenic-exposed animals as compared with that of unexposed animals. Similarly, arsenic-exposed animals failed to tolerate exogenously administered glucose (P < 0.001) as compared with that of unexposed animals. Likewise, insulin and glutathione concentrations were also significantly decreased (P < 0.001) in arsenic-exposed animals as compared with that of unexposed animals. The alterations in normal values of glucose, insulin, and glutathione exhibited the damaging effects of arsenic exposure in experimental rats. This study showed that arsenic exposed to human beings and animals through drinking water resulted in the disruption of pancreatic β-cell functioning that provoked the risk factor for development of DM. This study also suggested that long-term arsenic exposure induces hyperglycemia, inflammation, and oxidative stress that may lead to the onset of development of DM.

Bioaccumulation of arsenic and fluoride in vegetables from growing media: health risk assessment among different age groups

The current study was conducted to evaluate the arsenic (As) and fluoride (F^-) concentrations in growing media (stored rainwater and soil), of district Tharparkar, Pakistan. The bioaccumulation/transportation of As and F from growing media to different types of vegetables (wild cucumis, Indian squish and cluster bean) was evaluated. Total concentrations of As and F^- in stored rainwater samples were observed up to 585 μg/L and 32.4 mg/L, respectively, exceeding many folds higher than WHO provisional guideline values. The As and F^- contents in soil samples of nine agricultural sites were found in the range of 121-254 mg/kg and 115-478 mg/kg, respectively. The highest contents of As and F^- were observed in wild cucumis as compared to Indian squish and cluster bean (p < 0.05), grown in the same agricultural field. The bioaccumulation factors of As and F^- were to be > 4.00, indicating the high rate of transportation of As and F^- from growing media to vegetables. A significant positive correlation of As and F^- in vegetables with their concentrations in soil and water was observed (r > 0.60 with p < 0.05). The risk assessment elucidated that the population of different age group consuming local vegetables and drinking water contaminated with As and F^- may have adverse health effects.

Maternal exposure to arsenic and mercury in small-scale gold mining areas of Northern Tanzania

Artisanal and small-scale gold mining (ASGM) in Tanzania results in occupational exposures and environmental contamination to toxic chemical elements such as arsenic and mercury. Populations living in such areas may be exposed by various routes, and prenatal exposure to arsenic and mercury has been associated with adverse birth outcomes and developmental delays. The aim of this study was to determine if levels of arsenic and mercury differed among pregnant women living in areas with and without ASGM activities in Northern Tanzania. This cross-sectional study is part of the ongoing Mining and Health prospective longitudinal study. Spot urine samples and dried blood spots were collected at the antenatal health clinics from pregnant women (n = 1056) at 16-27 weeks gestation. Urine samples were analyzed for total arsenic (T-As) and dried blood spots were analyzed for total mercury (T-Hg). Women in the ASGM cohort had median T-As levels (9.4 μg/L; IQR: 4.9-15.1) and T-Hg levels (1.2 μg/L; IQR: 0.8-1.86) that were significantly higher than the median T-As levels (6.28 μg/L; IQR: 3.7-14.1) and T-Hg levels (0.66 μg/L; IQR: 0.3-1.2) of women in the non-ASGM cohort (Mann-Whitney U test, T-As: z = -9.881, p = 0.0005; T-Hg: z = -3.502, p < 0.0001). Among pregnant women from ASGM areas, 25% had urinary T-As and 75% had blood T-Hg above the established human biomonitoring reference values of 15 and 0.80 μg/L. In the ASGM cohort, lower maternal education and low socioeconomic status increased the odds of higher T-As levels by 20% (p < 0.05) and 10% (p < 0.05), respectively. Women involved in mining activities and those of low socioeconomic status had increased odds of higher T-Hg by 70% (p < 0.001) and 10% (p < 0.05), respectively. Arsenic and mercury concentrations among women in non-ASGM areas suggest exposure sources beyond ASGM activities that need to be identified. Arsenic and mercury levels in women in Tanzania are of public health concern and their association with adverse birth and child developmental outcomes will be examined in future studies on this cohort.

Trace elements in soil-vegetables interface: Translocation, bioaccumulation, toxicity and amelioration - A review

The contamination of soil and vegetables with trace elements is one of the most severe ecological problems in developing industrialized countries. Trace elements are released into the environment from natural and anthropogenic activities and accumulated in soil and vegetables through various pathways which ultimately affects the human health. The present review aimed at 1) discussing the anthropogenic sources in detail, 2) describing the bioaccumulation, absorption, and transportation of trace elements, 3) exploring the options to reduce the health risk due to consumption of contaminated vegetables, 4) identifying the research and policy gaps related to soil and vegetables contamination with trace elements. Besides these objectives, the present review also detailed the several factors which affect the rate of accumulation, toxicity mechanism, and effects of trace elements on vegetables and humans. Various toxicity indices for health risk assessment have also been described. It is suggested to evaluate the trace metals concentration in irrigation water and soil prior to plant the vegetable to minimize the possible contamination.

State of the science review of the health effects of inorganic arsenic: Perspectives for future research

Human exposure to inorganic arsenic (iAs) is a global health issue. Although there is strong evidence for iAs-induced toxicity at higher levels of exposure, many epidemiological studies evaluating its effects at low exposure levels have reported mixed results. We comprehensively reviewed the literature and evaluated the scientific knowledge on human exposure to arsenic, mechanisms of action, systemic and carcinogenic effects, risk characterization, and regulatory guidelines. We identified areas where additional research is needed. These priority areas include: (1) further development of animal models of iAs carcinogenicity to identify molecular events involved in iAs carcinogenicity; (2) characterization of underlying mechanisms of iAs toxicity; (3) assessment of gender-specific susceptibilities and other factors that modulate arsenic metabolism; (4) sufficiently powered epidemiological studies to ascertain relationship between iAs exposure and reproductive/developmental effects; (5) evaluation of genetic/epigenetic determinants of iAs effects in children; and (6) epidemiological studies of people chronically exposed to low iAs concentrations.

A Prospective Cohort Study Examining the Associations of Maternal Arsenic Exposure With Fetal Loss and Neonatal Mortality

Arsenic crosses the placenta, possibly increasing the risk of adverse reproductive outcomes. We aimed to examine the association between maternal arsenic exposure and fetal/neonatal survival using data from a prospective cohort study of 1,616 maternal-infant pairs recruited at a gestational age of ≤16 weeks in Bangladesh (2008-2011). Arsenic concentration in maternal drinking water was measured at enrollment. Extended Cox regression (both time-dependent coefficients and step functions) was used to estimate the time-varying association between maternal arsenic exposure and fetal/neonatal death (all mortality between enrollment and 1 month after birth). In a sensitivity analysis, we assessed gestational arsenic exposure using maternal urine samples taken at enrollment. We observed 203 fetal losses and 20 neonatal deaths. Higher arsenic exposure was associated with a slightly decreased mortality rate up to the middle of the second trimester, and then the mortality rate switched directions around 20 weeks' gestation. In the step function model, the hazard ratios for combined mortality (fetal loss and neonatal death) per unit increase in the natural log of drinking water arsenic concentration (μg/L) ranged from 1.35 (95% CI: 1.08, 1.69) in weeks 25-28 to 0.81 (95% CI: 0.65, 1.02) in weeks 9-12. This nonlinear association suggests that arsenic may exert survival pressure on developing fetuses, potentially contributing to survival bias, and may also indicate that arsenic toxicity differs by fetal developmental stage.

K. S, Ghosh D. Arsenic Exposures, Poisoning, and Threat to Human Health

Arsenic (As) is a naturally occurring metalloid which induces high toxicity to both human and animal health. Although As has some applications in industrial, medicinal and agricultural fields, the increasing concentrations of As in drinking water sources had made it a potential threat to living organisms. Inorganic As is naturally present in groundwater and is adsorbed by plants and crops through the irrigation system. This leads to its accumulation in crops and translocation to humans and animals through food. Increased levels of As can cause various health disorders through acute and chronic exposures such as gastrointestinal, hepatic, respiratory, cardiovascular, integumentary, renal, neurological, and reproductive disorders including stillbirth and infant mortality. Arsenic is also capable of inducing epigenetic changes, thereby causing gene mutations. This chapter focuses on the possible sources of As, leading to environmental contamination and followed by its hazardous effects which pave the way to various human health manifestations.