Arsenic Concentrations in Household Drinking Water: A Cross-Sectional Survey of Pregnant Women in Tacna, Peru, 2019

Concentrations of Lead and Arsenic in Mother's Milk and Children's Blood in Peruvian Breastfeeding Dyads

BACKGROUND

Toxic trace elements could enter human milk through mothers' food consumption, drinking water, air, or incidental soil ingestion, and are of concern to the nursing infant.

RESEARCH AIM

To determine the concentration of toxic trace elements (lead and arsenic) in Peruvian mothers' milk and their association with blood concentrations in their own infants 3-20 months old.

METHOD

This exploratory, cross-sectional study, carried out in Peru, included breastfeeding mother/child dyads (N = 40). Following standardized protocols, biospecimens of human milk and child's blood were collected.

RESULTS

Lead and arsenic concentrations in milk were above the method detection limits in 73% and 100% of samples with median concentrations of 0.26 µg/L (IQR = 0.10, 0.33 µg/L) and 0.73 µg/L (IQR = 0.63, 0.91 µg/L), respectively. Concentrations of lead and arsenic in blood were 2.05 µg/dL (SD = 1.35), and 1.43 µg/dl (geometric mean: SD = 1.39), respectively. Blood lead concentrations in 12.5% (n = 5) of the samples were above the U.S. Center for Disease Control and Prevention reference value (< 3.5 µg/dl), and over half of arsenic concentrations were above the acceptable levels of < 1.3 µg/dl (Mayo Clinic Interpretative Handbook). Our results showed that for every one-month increase in age, lead blood concentrations increased by 0.1 µg/dl (p = 0.023). Additionally, every 1 µg/L increase in the mother's milk arsenic was associated with a 1.40 µg/dl increase in the child's blood arsenic concentration.

CONCLUSIONS

Implementing effective interventions to decrease the toxic exposure of reproductive-aged women is needed in Peru and worldwide.

Effects of Gestational Arsenic Exposures on Placental and Fetal Development in Mice: The Role of Cyr61 m6A

BACKGROUND

Several epidemiological investigations demonstrated that maternal arsenic (As) exposure elevated risk of fetal growth restriction (FGR), but the mechanism remains unclear.

OBJECTIVES

This study aimed to investigate the effects of gestational As exposure on placental and fetal development and its underlying mechanism.

METHODS

Dams were exposed to 0.15, 1.5, and 15 mg / L NaAsO 2 throughout pregnancy via drinking water. Sizes of fetuses and placentas, placental histopathology, and glycogen content were measured. Placental RNA sequencing was conducted. Human trophoblasts were exposed to NaAsO 2 (2 μ M ) to establish an in vitro model of As exposure. The mRNA stability and protein level of genes identified through RNA sequencing were measured. N 6 -Methyladenosine (m 6 A ) modification was detected by methylated RNA immunoprecipitation-quantitative real-time polymerase chain reason (qPCR). The binding ability of insulin-like growth factor 2 binding protein 2 to the gene of interest was detected by RNA-binding protein immunoprecipitation-qPCR. Intracellular S-adenosylmethionine (SAM) and methyltransferase activity were determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and colorimetry, respectively. In vitro As + 3 methyltransferase (As3MT) knockdown or SAM supplementation and in vivo folic acid (FA) supplementation were used to evaluate the protective effect. A case-control study verified the findings.

RESULTS

Sizes of fetuses (exposed to 1.5 and 15 mg / L NaAsO 2 ) and placentas (exposed to 15 mg / L NaAsO 2 ) were lower in As-exposed mice. More glycogen + trophoblasts accumulated and the expression of markers of interstitial invasion was lower in the 15 mg / L NaAsO 2 -exposed mouse group in comparison with control. Placental RNA sequencing identified cysteine-rich angiogenic inducer 61 (Cyr61) as a candidate gene of interest. Mechanistically, mice and cells exposed to As had lower protein expression of CYR61, and this was attributed to a lower incidence of Cyr61 m 6 A . Furthermore, cells exposed to As had lower methyltransferase activity, suggesting that this could be the mechanism by which Cyr61 m 6 A was affected. Depletion of intracellular SAM, a cofactor for m 6 A methyltransferase catalytic domain, partially contributed to As-induced methyltransferase activity reduction. Either As3MT knockdown or SAM supplementation attenuated As-induced Cyr61 m 6 A down-regulation. In mice, FA supplementation rescued As-induced defective trophoblastic invasion and FGR. In humans, a negative correlation between maternal urinary As and plasma CYR61 was observed in infants who were small for gestational age.

DISCUSSION

Using in vitro and in vivo models, we found that intracellular SAM depletion-mediated Cyr61 m 6 A down-regulation partially contributed to As-induced defective trophoblastic invasion and FGR. https://doi.org/10.1289/EHP12207.

Heavy metal(loid)s contamination in water and sediments in a mining area in Ecuador: a comprehensive assessment for drinking water quality and human health risk

Elevated heavy metal(loid)s concentrations in water lower its quality posing a threat to consumers. This study aims to assess the human health risk caused by heavy metal(loid)s in tap water in Santa Rosa city, Ecuador, and the ecological risk of stream water and sediments in the Santa Rosa River. Concentrations of As, Cd, Cr, Cu, Ni, Pb, and Zn were evaluated in tap waters, stream waters, and sediment samples during the rainy and dry seasons. The Metal Index (MI), Geo-accumulation Index (I_geo), Potential Ecological Risk Index (PERI), and the levels of carcinogenic (CR) and non-carcinogenic risk (HQ) were determined. The results revealed severe pollution levels, mainly in Los Gringos and El Panteon streams, both tributaries of the Santa Rosa River, the primary water source for Santa Rosa inhabitants. More than 20% of the surface water samples showed severe contamination (MI > 6), and 90% of the tap water samples presented a MI value between 1 and 4, which indicates slight to moderate pollution. Drinking water displayed high levels of As, with 83% of the tap water samples collected from households in the dry season above the recommended concentration set by the World Health Organization and Ecuadorian legislation. The I_geo-Cd in the sediment samples was significantly high (I_geo > 3), and the PERI showed very high ecological risk (PERI > 600), with Cd as the main pollutant. HQ and CR were above the safe exposure threshold, suggesting that residents are at risk from tap water consumption, with As being the primary concern.

High Prevalence of Chemical and Microbiological Drinking Water Contaminants in Households with Infants Enrolled in a Birth Cohort-Piura, Peru, 2016

Chemical and microbiological drinking water contaminants pose risks to child health but are not often evaluated concurrently. At two consecutive visits to 96 households in Piura, Peru, we collected drinking water samples, administered health and exposure questionnaires, and collected infant stool samples. Standard methods were used to quantify heavy metals/metalloids, pesticides, and Escherichia coli concentrations in water samples. Stool samples were assayed for bacterial, viral, and parasitic enteropathogens. The primary drinking water source was indoor piped water for 70 of 96 households (73%); 36 households (38%) stored drinking water from the primary source in containers in the home. We found high prevalence of chemical and microbiological contaminants in household drinking water samples: arsenic was detected in 50% of 96 samples, ≥ 1 pesticide was detected in 65% of 92 samples, and E. coli was detected in 37% of 319 samples. Drinking water samples that had been stored in containers had higher odds of E. coli detection (adjusted odds ratio [aOR]: 4.50; 95% CI: 2.04-9.95) and pesticide detection (OR: 6.55; 95% CI: 2.05-21.0) compared with samples collected directly from a tap. Most infants (68%) had ≥ 1 enteropathogen detected in their stool. Higher odds of enteropathogen infection at the second visit were observed among infants from households where pesticides were detected in drinking water at the first visit (aOR: 2.93; 95% CI: 1.13-7.61). Results show concurrent risks of exposure to microbiological and chemical contaminants in drinking water in a low-income setting, despite high access to piped drinking water.

Concentrations of arsenic, cadmium, and lead in herbal infusion tea bags marketed in Tacna, Peru

The concentrations of arsenic, cadmium, and lead in infusion tea bags of Camellia sinensis (tea), Pimpinella anisum (anise), Matricaria recutita (chamomile), Peumus boldus (boldo), and Cymbopogon citratus (lemongrass) were determined by graphite furnace atomic absorption spectroscopy (GFAAS) for four commercial brands sold in Tacna, Peru, to compare these concentrations with international standards. The moderate level of arsenic obtained for C. sinensis (0.294 mg kg^-1) exceeded the Codex Alimentarius standard for three of the four analyzed brands, while the level of arsenic in P. boldus (0.220 mg kg^-1) exceeded the same standard and the Mercado Común del Sur (MERCOSUR) parameters for only one brand. The moderate level of cadmium outlined in the Codex Alimentarius and by the World Health Organization (WHO) was exceeded by two infusion tea bag brands of M. recutita (0.210 mg kg^-1) and one brand of C. citratus (0.134 mg kg^-1). Finally, based on the MERCOSUR parameters, moderate levels of lead were exceeded by only one brand of C. citratus (0.535 mg kg^-1). To evaluate possible health risks, we also calculated the hazard index (HI) of the heavy metals in the target herbal tea bags. The values obtained were less than 1, showing negligible noncarcinogenic health risks for consumers. Despite this information and because of the elevated concentrations of arsenic, cadmium, and lead obtained in some of our results, we suggest more detailed studies to obtain more information about the potential toxicity of these products to humans.

Hydrochemical Characteristics of Arsenic in Shallow Groundwater in Various Unconsolided Sediment Aquifers: A Case Study in Hetao Basin in Inner Mongolia, China

This study focused on the entire Hetao Basin, which can fall into four hydrogeological units, the Houtao Plain, Sanhuhe Plain, Hubao Plain, and South Bank Plain of the Yellow River, all of which are under different geological and environmental conditions. To systematically investigate the hydrochemical characteristics and spatial distribution of high-As groundwater (As > 10 μg/L), 974 samples were collected from shallow groundwater. As indicated from the results, high-As groundwater had an extensive distribution, and its spatial distribution in the four hydrogeological units exhibited significant variability. Three concentrated distribution areas were reported with high-As groundwater, which were all in the discharge areas of groundwater, and the arsenic contents in the groundwater were found to exceed 50 μg/L. The hydrochemical types of high-As groundwater in the HT Plain and the SHH Plain consisted of HCO3 SO4·Cl for anions and Na for cations, while those in the other two plains included HCO3 for anions as well as Na·Mg·Ca for cations. According to the pH values, the groundwater was weakly alkaline in the areas with high-As groundwater, and arsenic primarily existed as arsenite. Furthermore, high-As groundwater in the Hetao Basin was characterized by high contents of Fe (mean value of 2.77 mg/L) and HCO3− (mean value of 460 mg/L) and a low relative concentration of SO42− (average value of 310 mg/L). This study did not identify any significant correlation between groundwater arsenic and other ions (e.g., Fe2+, Fe3+, HCO3−, SO42−, NO2− and NO3−) in the entire Hetao Basin over a wide range of hydrogeological units. The results remained unchanged after the four hydrogeological units were analyzed. The special sedimentary environment evolution of the Hetao Basin was found as the prerequisite for the formation of high-arsenic groundwater. Furthermore, groundwater runoff conditions and hydrogeochemical processes in the basin were indicated as the factors controlling the formation of high-arsenic groundwater.

Total Urinary Arsenic and Inorganic Arsenic Concentrations and Birth Outcomes in Pregnant Women of Tacna, Peru: A Cross-Sectional Study

Inorganic arsenic exposure has been linked to the development of several health conditions, including adverse birth outcomes; and around 150 million of people worldwide are exposed to levels above the WHO suggested limit of 10 μg/L. A recent risk assessment in pregnant women of Tacna, of this same population performed by our group, found that 70.25% were exposed to arsenic concentrations in drinking water ≥25 μg/L. The present study aimed to evaluate the relationship between prenatal total urinary arsenic (U-tAs) and inorganic arsenic (U-iAs) with adverse birth outcomes. A total of 147 pregnant women from the province of Tacna, Peru, during February - March, 2019, were evaluated for U-tAs and U-iAs exposure during their second trimester of pregnancy, while the birth records of their children were collected from the local hospital. The geometric mean U-tAs was 43.97 ± 25.88 μg/L (P₅₀ 22.30, range 5.99 - 181.94 μg/L) and U-iAs was 5.27 ± 2.91 μg/L. Controlling for maternal age, pre-pregnancy BMI, parity, mother's education and newborn sex, no relationship was observed between tertile of U-tAs and the birth outcomes considered, although we found an apparent but statistically non-significant dose-response relationship for small-for-gestational-age 2.38% ( 95% CI 0.003, 0.16), versus 7.32% (95% CI 0.02, 0.21%), versus 8.57% (0.03, 0.25%). This finding requires further evaluation considering other factors such as metabolic arsenic species, additional maternal covariates and ethnicity.