Exposure to arsenic through breast milk from mothers exposed to high levels of arsenic in drinking water: Infant risk assessment

Systematic review and meta-analysis of arsenic concentration in drinking water sources of Iran

Recent studies have found arsenic contamination of drinking water in some parts of Iran, as in many other countries. Thus, a comprehensive systematic review is necessary to assess the distribution and concentration of arsenic in drinking water sources. For this purpose, articles published from the first identification until December 2023, were retrieved from various national and international databases. Of all the studies examined (11,726), 137 articles were selected for review based on their conceptual relationship to this survey. A review of the extracted studies presented that ICP methods (ICP-MS, ICP-OES, 56%) and atomic absorption spectrophotometry (AAS, 34.1%) were the two most commonly used techniques for the analysis of arsenic in water samples. The order of arsenic content in the defined study areas is descending, as follows: northwest ˃ southeast ˃ southwest ˃ northeast. A review of studies performed in Iran depicted that provinces such as Kurdistan, Azerbaijan, and Kerman have the highest arsenic concentrations in water resources. Accordingly, the maximum concentration of arsenic was reported in Rayen, Kerman, and ranged from < 0.5-25,000 µg/L. The primary cause of elevated arsenic levels in water resources appears to be geologic structure, including volcanic activity, biogeochemical processes, sulfur-bearing volcanic rocks, Jurassic shale, the spatial coincidence of arsenic anomalies in tube wells and springs, and, to some extent, mining activities. The findings of the presented survey indicate that it is essential to take serious measures at the national level to minimize the health risks of arsenic contamination from drinking water consumption.

Arsenic level in groundwater and biological samples in Khanewal, Pakistan

Groundwater is the most valuable natural source in our earth's planet, being contaminated in various regions worldwide. Despite considerable research, there are scarce data regarding arsenic (As) levels in groundwater and its build-up in biological samples in Pakistan. The current investigation analyzed As contamination in four tehsils of District Khanewal (Kabirwala tehsil, Jahaniyan tehsil, Mian Channu tehsil, and Khanewal tehsil). For that, 123 groundwater samples, 19 animal milk samples, 20 human nails, and 20 human hair samples were collected from the study area. Arsenic concentration in groundwater was up to 51.8 µg/L with an average value of 7.2 µg/L. About 28 water samples (23%) had As contents > WHO limit and 38 samples (31%) > DEP-NJ limit. Low levels of As were detected in biological samples. Average As levels were 23 µg/L in the milk samples and 298 µg/kg in human hair. Arsenic contents were not detected in nail samples, except in one sample from Kabirwala tehsil. The maximum values of hazard quotient and cancer risk in District Khanewal were 4.9 and 0.0022, respectively. It is anticipated that long-term use of As-containing water may led to poisoning of humans in the study area, especially in Kabirwala. Therefore, it is necessary to monitor As contamination in the groundwater of Kabirwala tehsil to reduce the potential health hazards.

Arsenic level in drinking water, its correlation with water quality parameters, and associated health risks

This study aimed to evaluate the occurrence and likelihood of health risks related to arsenic in drinking water of all counties of the Hamadan province in the northwest of Iran. In this work, 370 samples were collected from all of the water resources of urban and rural regions, during 5 years (2017 to 2021). Oracle Crystal Ball software was used to perform the Monte Carlo simulation and investigate the potential health risks. According to the results, the average values of arsenic in the nine counties were in the order Kabudarahang (40.1 ppb), Malayer (13.1 ppb), Nahavand (6.1 ppb), Bahar (2.05 ppb), Famenin (0.41 ppb), Asadabad (0.36 ppb), Tuyserkan (0.28 ppb), Razan (0.14 ppb), and Hamadan (< 0.1 ppb). The highest concentration of arsenic occurred in Kabudarahang with a maximum value of 185 ppb. In the spring season, the average concentration of the cations, including calcium, magnesium, sodium, lead, cadmium, and chromium, obtained 109.51 mg/l, 44.67 mg/l, 20.50 mg/l, 88.76 ppb, 0.31 ppb, and 0.02 ppb, respectively. Based on the Delphi classification, the P 90% of oral lifetime cancer risk, in Hamadan province, were within level II (low risk) to VII (extremely high risk). The risk analysis revealed there was a possible carcinogenic risk to humans from oral exposure to As-contaminated groundwater, especially in Kabudarahang county. Therefore, there is an urgent need for management and precise measures in contaminated areas to reduce and prevent the adverse health effects of arsenic.

A review on arsenic in the environment: bio-accumulation, remediation, and disposal

Arsenic is a widespread serious environmental pollutant as a food chain contaminant and non-threshold carcinogen. Arsenic transfer through the crops-soil-water system and animals is one of the most important pathways of human exposure and a measure of phytoremediation. Exposure occurs primarily from the consumption of contaminated water and foods. Various chemical technologies are utilized for As removal from contaminated water and soil, but they are very costly and difficult for large-scale cleaning of water and soil. In contrast, phytoremediation utilizes green plants to remove As from a contaminated environment. A large number of terrestrial and aquatic weed flora have been identified so far for their hyper metal removal capacity. In the panorama presented herein, the latest state of the art on methods of bioaccumulation, transfer mechanism of As through plants and animals, and remediation that encompass the use of physicochemical and biological processes, i.e., microbes, mosses, lichens, ferns, algae, and macrophytes have been assessed. Since these bioremediation approaches for the clean-up of this contaminant are still at the initial experimental stages, some have not been recognized at full scale. Nonetheless, extensive research on these primitive plants as bio-accumulators can be instrumental in controlling arsenic exposure and rehabilitation and may result in major progress to solve the problem on a worldwide scale.

Comparative Biomonitoring of Arsenic Exposure in Mothers and Their Neonates in Comarca Lagunera, Mexico

Multiple comorbidities related to arsenic exposure through drinking water continue to be public problems worldwide, principally in chronically exposed populations, such as those in the Comarca Lagunera (CL), Mexico. In addition, this relationship could be exacerbated by an early life exposure through the placenta and later through breast milk. This study conducted a comparative analysis of arsenic levels in multiple biological samples from pregnant women and their neonates in the CL and the comparison region, Saltillo. Total arsenic levels in placenta, breast milk, blood, and urine were measured in pregnant women and their neonates from rural areas of seven municipalities of the CL using atomic absorption spectrophotometry with hydride generation methodology. The average concentrations of tAs in drinking water were 47.7 µg/L and 0.05 µg/L in the exposed and non-exposed areas, respectively. Mean levels of tAs were 7.80 µg/kg, 77.04 µg/g-Cr, and 4.30 µg/L in placenta, blood, urine, and breast milk, respectively, in mothers, and 107.92 µg/g-Cr in neonates in the exposed group, which were significantly higher than those in the non-exposed area. High levels of urinary arsenic in neonates were maintained 4 days after birth, demonstrating an early arsenic exposure route through the placenta and breast milk. In addition, our study suggested that breastfeeding may reduce arsenic exposure in infants in arsenic-contaminated areas. Further studies are necessary to follow up on comorbidities later in life in neonates and to provide interventions in this region.

Contamination of breast milk with lead, mercury, arsenic, and cadmium in Iran: a systematic review and meta-analysis

Breast milk is a complete food for the development of the newborn, but it can also be an important route for environmental pollutants transmission to the infants. This study was aimed to evaluate the status of heavy metals including lead (Pb), mercury (Hg), cadmium (Cd) and arsenic (As) in the breast milk of Iranian mothers. The international databases including Scopus, PubMed, Web of Science and the Persian electronic databases including Scientific Information Database, IranMedex and Magiran were examined to find relevant articles published until July 2021. A total of 23 studies examined the levels of toxic metals in Iranian breast milk samples. According to the findings, the pooled average concentrations (µg/L) of Pb, Cd, Hg and As were 25.61, 2.40, 1.29 and 1.16, respectively. The concentration of Hg and Pb in colostrum milk was more than twice of mature milk. The Hg mean concentration in the breast milk of mothers with at least one amalgam-filled tooth was approximately three times that of mothers without amalgam-filled teeth. Risk assessment analysis indicated that the intake of Pb and Hg by infants through breastfeeding can be considered a health concern in Iran. It seems necessary to reduce the Pb exposure of pregnant and lactating women in Iran. However, more extensive studies are needed to clarify the toxic metals' exposure status of infants through breast milk in other parts of the country.

Correlation between As, Cd, Hg, Pb and Sn concentration in human milk and breastfeeding mothers' food consumption: a systematic review and infants' health risk assessment

Mothers' food and water consumption appear to be determining factors for infants' potentially toxic elements exposure through human milk. Therefore, this systematic review aimed to assess correlations between As, Cd, Hg, Pb and/or Sn concentration in human milk and breastfeeding mothers' food consumption, with later infants' health risk assessment. Estimated Daily Intakes of such elements by infants were also calculated and compared with reference values (RfD or BMDL01). Among 5.663 identified studies, 23 papers remained for analysis. Potentially toxic elements concentration in human milk presented positive correlation with seafood (As, Hg), fresh vegetables (Hg, Cd), cereals (Hg, Cd), cheese, rice, potatoes, private and well-water supply (Pb), wild meat (Pb, Cd) and milk, dairy products, dried fruits and oilseeds (Cd) mothers' consumption. Red meat, caffeinated drinks, and dairy products consume presented negative correlations (Pb). No correlations were found for Sn. Infants from three studies presented high Hg exposition through human milk (> 0. 1 μg/kg PC-1 day-1), as well as observed for Pb in one study (> 0. 5 μg/kg PC-1 day-1). Potentially toxic elements can damage infants' health when they are present in mothers' diet due to the infants' high vulnerability. Therefore, these results raise important issues for public health.Supplemental data for this article is available online at https://doi.org/10.1080/10408398.2022.2056869 .

Application of fingernail samples as a biomarker for human exposure to arsenic-contaminated drinking waters

This study evaluated the relationship between arsenic uptake via drinking water ingestion and arsenic concentration in fingernails as a biomarker for human exposure. For this purpose, we collected fingernail samples from 40 healthy participants of arsenic-affected rural regions of Kaboudrahang County, the west of Iran. A total of 49 fingernail samples were also collected from individuals who lived in areas where contamination of drinking water sources with arsenic had not been reported. It was found that the fingernails arsenic contents in 50 and 4.08% of the samples collected from arsenic-contaminated and reference villages were higher than the normal arsenic values of nails (0.43-1.08 µg/g), respectively. Based on the results of adjusted multiple linear regression, a significant association was found between groundwater and fingernails arsenic concentration (p < 0.001). Moreover, a statistically significant association was shown between arsenic in the fingernail samples and gender (p = 0.037). Fingernails arsenic contents were not significantly affected by other variables including age, smoking habits, and BMI (p > 0.05). In light of the results of this study, the use of biological indicators such as fingernail tissues due to easier sampling and less risk of external contamination is suitable for assessing exposure to heavy metals in contaminated areas.

Health Risk Assessments of Selected Trace Elements and Factors Associated with Their Levels in Human Breast Milk from Pretoria, South Africa

While breast milk is the recommended food for infants up to at least six months, exogenously derived compounds such as trace elements have been widely reported in human milk which may make it become toxic or a source of pollutants to the infants. Numerous short- and long-term health effects have been associated with high body-burdens of trace elements, which are amplified in infants. The current study determined the levels and possible contributing factors of six trace elements in breast milk of nursing mothers from a local hospital in Pretoria. Extraction of trace elements employed a digestion technique using perchloric and nitric acid in a ratio of 1:3, while Inductively Coupled Plasma-Membrane Spectrophotometry was used to identify and quantify their levels in breast milk. Concentrations of Cr and Mn were the highest in breast milk, with values ranging from 0.30 to 5.72 µg/L and 0.23 to 5.13 µg/L, respectively. Levels of Co, As, Pb and Cd ranged from Collapse

Key Words

• arsenic
• breast milk and passive smoking
• chromium
• manganese

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MESH Headings

• Environmental Pollutants
• Female
• Humans
• Milk, Human/chemistry
• Risk Assessment
• South Africa
• Trace Elements/analysis

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Grants Collapse

Affiliation(s)

Joshua O. Olowoyo Department of Biology, Sefako Makgatho Health Sciences University, P.O Box 139, Pretoria 0204, South Africa; (L.R.M.); (P.M.M.)
Linda R. Macheka
Phiona M. Mametja

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Combined effects of arsenic and palmitic acid on oxidative stress and lipid metabolism disorder in human hepatoma HepG2 cells

The toxicity of arsenic (As) can be influenced by many nutrients in food. However, the combined effects and underlying mechanisms of As and palmitic acid (PA) are still unclear. Here, cell viability, oxidative stress, lipids accumulation, gene expression profiles, and metabolome profiles of human hepatoma HepG2 cells exposed to As, PA, and As + PA were analyzed and compared. Results showed that co-exposure of 100 μM PA and 2 μM As induced lower cell viability, higher intracellular reactive oxygen species level, more lipid droplet accumulation, and more intracellular triglyceride contents than As alone or PA alone exposure. High-throughput quantitative PCR and ¹H NMR-based metabolomics analysis showed that co-exposure of As and PA caused all toxic effects on gene expression and metabolome profiles induced by As alone or PA alone exposure, and showed higher toxicities. Gene expression profiles in the As + PA group had higher similarity with those in the As group than the PA group. However, PA played a more important role in metabolism disorder than As in their interactive effects. Oxidative stress and lipid metabolism disorder were found to be the main toxic effects in the As + PA group. Several differentially expressed genes (such as OXR1, OXSR1, INSR, and PPARA) and changed metabolites (such as pyruvate, acetate, and L-phenylalanine) were involved in the combined toxicity of As and PA. This study provides basic information on the interactive effects of As and PA, which is useful for the health risk assessment of As and FFA.

A systematic review and meta-analysis of human biomonitoring studies on exposure to environmental pollutants in Iran

Population exposure to environmental contaminants can be precisely observed through human biomonitoring studies. The present study aimed to systematically review all the biomonitoring studies conducted in Iran on some selected carcinogen environmental pollutants. In this systematic review study, 11 carcinogen agents were selected including arsenic, cadmium, chromium, nickel, lindane, benzene, trichloroethylene (TCE), pentachlorophenol (PCP), radon-222, radium-224, - 226, - 228, and tobacco smoke. The Web of Science, PubMed, and Scopus databases were searched for peer-reviewed articles published in English. After several screening steps, data were extracted from the studies. Meta-analyses (a random-effect model using the DerSimonian-Laired method) were performed only for the biomarkers with more than three eligible articles, including cadmium in blood and breast milk, and arsenic in breast milk. Methodological quality of the studies was assessed using the Newcastle-Ottawa Quality Assessment Scale adapted for cross-sectional studies. Of the 610 articles found in the database search, 30 studies were eligible for qualitative review, and 13 were included in the meta-analysis (cadmium in blood (n = 3), cadmium in breast milk (n = 6), and arsenic in breast milk (n = 4)). The overall pooled average concentrations (95% CI) of cadmium in blood, cadmium in breast milk, and arsenic in breast milk were 0.11 (95% CI: 0.08, 0.14), 5.38 (95% CI: 3.60, 6.96), and 1.42 (95% CI: 1.02, 1.81) µg/L, respectively. These values were compared with the biomarker concentrations in other countries and health-based guideline values. This study showed that there is a need for comprehensive action plans to reduce the exposure of general population to these environmental contaminants.

The relationship between chronic exposure to arsenic through drinking water and hearing function in exposed population aged 10-49 years: A cross-sectional study

It has been documented that arsenic has a potential risk to human health and identified as a risk factor for hearing impairment. However, there are few studies that confirm the ototoxic effect of arsenic, especially on the human auditory system. Therefore, the current study was conducted to investigate the correlation between auditory thresholds at different frequencies (0.25, 0.5, 1, 2, 4 and 8 kHz) and arsenic levels in drinking water samples. A total of 240 people, divided into two equal groups: exposed and reference, were selected for the auditory tests. It should be noted that, at frequencies from 0.25 to 1 kHz, no hearing loss was observed in the both groups. Based on the results, no significant correlations (p > 0.05) were found between hearing thresholds and confounding variables including gender and BMI. However, smoking and age are known to be the main variables for hearing loss in univariate regression analysis. In the case of age, the hearing loss risk in the older participants was increased compared with the younger participants (4 kHz (OR =1.09; 95% CI: 1.04, 1.13) and 8 kHz (OR =1.12; 95% CI: 1.06, 1.18)). Smoking habits had significant associations with hearing loss risk at 4 kHz (OR = 3.48; 95% CI: 1.47, 8.22) and 8 kHz (OR = 3.01; 95% CI: 1.14, 7.95). The multivariate regression analysis showed that age, smoking status, and exposure to arsenic were significantly associated with increased risk of hearing loss. Moreover, no statistically significant correlation (p˃0.05) was observed between arsenic exposure and hearing loss in the logistic regression model compared to the reference group. These outcomes suggest that further investigation and cohort studies with a larger number of participants should be conducted to find an association between arsenic exposure and hearing loss in general population.

Transport of arsenolipids to the milk of a nursing mother after consuming salmon fish

OBJECTIVE

We address two questions relevant to infants' exposure to potentially toxic arsenolipids, namely, are the arsenolipids naturally present in fish transported intact to a mother's milk, and what is the efficiency of this transport.

METHODS

We investigated the transport of arsenolipids and other arsenic species present in fish to mother's milk by analyzing the milk of a single nursing mother at 15 sampling times over a 3-day period after she had consumed a meal of salmon. Total arsenic values were obtained by elemental mass spectrometry, and arsenic species were measured by HPLC coupled to both elemental and molecular mass spectrometry.

RESULTS

Total arsenic increased from background levels (0.1 μg As kg-1) to a peak value of 1.72 μg As kg-1 eight hours after the fish meal. The pattern for arsenolipids was similar to that of total arsenic, increasing from undetectable background levels (< 0.01 μg As kg-1) to a peak after eight hours of 0.45 μg As kg-1. Most of the remaining total arsenic in the milk was accounted for by arsenobetaine. The major arsenolipids in the salmon were arsenic hydrocarbons (AsHCs; 55 % of total arsenolipids), and these compounds were also the dominant arsenolipids in the milk where they contributed over 90 % of the total arsenolipids.

CONCLUSIONS

Our study has shown that ca 2-3 % of arsenic hydrocarbons, natural constituents of fish, can be directly transferred unchanged to the milk of a nursing mother. In view of the potential neurotoxicity of AsHCs, the effects of these compounds on the brain developmental stage of infants need to be investigated.