Mercury, Lead, Cadmium, and Barium Levels in Human Breast Milk and Factors Affecting Their Concentrations in Hamadan, Iran

Assessment of toxic metals and trace elements in breast milk of mothers and their health risks to infants: A cross-sectional study in Ardabil, Northwest Iran

This research aimed to assess the potential health risks for infants and measure the concentrations of heavy metal substances in the breast milk of mothers residing in Ardabil, Iran. The study was descriptive and cross-sectional in nature. Ten health centers in Ardabil City were selected for the research. The ages of participating mothers ranged from 19 to 39 years, and breast milk samples were collected from those who were 1-12 months postpartum. A 25-item questionnaire was used to evaluate the participants' exposure to heavy metals in their environment and diet. Data analysis was performed using the non-parametric Mann-Whitney U test, resulting in a p-value greater than 0.05. The average body mass index (BMI) of breastfeeding mothers was 26.26 ± 3.73. Spike recovery values ranged from 92 % to 106 %, indicating reliable performance within the ICP-MS range. The limit of detection (LOD) during routine sample analysis was 0.001 μg/L. The daily intake (DI) of lead (Pb), arsenic (As), and chromium (Cr) for infants was calculated. According to the findings, copper (Cu) had the highest average concentration in breast milk at 803.94 μg/L, while cadmium (Cd) had the lowest at 1.87 μg/L. Additionally, potassium (K) exhibited the highest average concentration at 490.49 mg/L, whereas molybdenum (Mo) had the lowest at 0.8 μg/L. The average daily intake of Pb, As, and Cr through breastfeeding was measured at 3.39, 0.799, and 3.47 μg/kg-bw/day, respectively. The results confirmed the presence of mercury (Hg), As, and Pb in every milk sample collected from lactating mothers in Ardabil, indicating potential exposure of infants to elevated levels of toxic heavy metals.

Total proteome and calcium-binding proteins from human breast milk: Exploring the impact of tobacco smoke exposure and environmental factors

This study integrates proteome analysis of human breast milk (HBM) from a homogeneous group of mothers who are of similar age and live in the same geographical area, along with an analysis of essential and potentially toxic elements in HBM in relation to lifestyle and environmental factors. This preliminary proteomic study, which examined 11 samples of HBM from lactating women, identified a total of 1619 proteins across all samples, revealing significant differences in proteomes influenced by lactation stages, parity, and exposure to tobacco smoke. The pilot study aimed to explore the feasibility of correlating certain proteins with several elements, considered as indicators of tobacco smoke and environmental influences on HBM. Notably, a clear and significant correlation was found between altered calcium content in HBM and the proteome fraction associated with calcium-binding proteins. The findings suggest that all analyzed factors impact the HBM proteome and the activity of certain enzymes.

Occurrences of heavy metal in breast milk in China: Results of the third national breast milk survey

To investigate the exposure of infants to heavy metal during lactation, breast milk from 24 provinces in China were detected. Among As, Cd, Cr, Hg, and Pb, the detection frequencies of As (85 %, 0.50 μg/L) and Cd (91 %, 0.15 μg/L) in breast milk were notably high. The concentrations of As in breast milk from coastal provinces were significantly higher than those in inland provinces, the discrepancy that was strongly associated with the intake of seafood. The levels of Cd in breast milk were markedly higher in southern provinces than those in northern provinces, the distinction that was significantly linked to the dietary consumption of Cd. Contrasting with the findings of the second national breast milk survey in China, the levels of As, Cd and Pb in the third one decreased evidently. Moreover, comparing to the global levels of heavy metals in breast milk, their levels in Chinese breast milk were comparatively low. Risk assessment for infants showed that heavy metals in breast milk from most regions of China did pose no health hazard. Continuous monitoring of heavy metal levels in breast milk is crucial for the health of breastfed infant.

Evaluating Heavy Metals in Human Breast Milk: a Cross-Sectional Study from Mining and Agricultural Areas in Northwestern Iran

This study aimed to assess the levels of heavy metals in the breast milk of women residing in the mining and agricultural areas of East Azerbaijan province in Iran. This cross-sectional study analyzed 68 lactating mothers from mining (n = 28) and agricultural (n = 40) areas of East Azerbaijan province in Iran between June 2022 and March 2023. The study used an Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) to measure the concentrations of heavy metals, including arsenic (As), chromium (Cr), copper (Cu), and iron (Fe). A semi-quantitative food frequency questionnaire (SQ-FFQ) was used to collect data on the dietary and sociodemographic characteristics of the mothers. Although the concentration of arsenic (As) was below the limit of detection (LOD), the mean concentrations of chromium (Cr), copper (Cu), and iron (Fe) were 1.11, 0.87, and 13.25 mg/L in agricultural areas and 0.83, 0.93, and 11.35 mg/L in mining areas, respectively. The concentrations of Cr (p < 0.001) and Fe (p = 0.019) were significantly higher in the breast milk of women residing in agricultural areas. However, the concentration of Cu was significantly higher (p = 0.085) in the breast milk of women living in mining areas. Additionally, lactation age had a significant effect on Cu levels (p = 0.015), with a negative coefficient of -0.011. The study indicates that the levels of heavy metals in breast milk can be influenced by the exposure to pesticides, fertilizers, volcanic soil, and disparities in access to post-natal care and iron supplements.

Individualized support for breastfeeding in a case of elevated blood lead levels: A case report

Introduction

Lead is a known toxicant that affects all tissues in the body, most notably the brains of developing children. However, there are limited data on the dynamics of lead transfer via breastmilk and its short-term and long-term consequences. Much of the available data come from areas of the world where numerous sources of lead complicate our understanding of the effects of lead exposure via breast milk.

Case Presentation

We present trends in blood lead levels in a breastfeeding dyad, where the only source of lead exposure identified was prior to pregnancy, without other known ongoing lead exposures for the lactating parent or infant.

Discussion and Conclusions

In this case, all lead exposure in the infant was presumed to come from in utero transmission and breastfeeding; and infant blood lead levels varied significantly with initiation and interruption of breastfeeding. This case is discussed in the context of current models for predicting transfer of lead in breastmilk and highlights pathophysiologic considerations for understanding lead transfer in the breastfeeding dyad.

Mercury in saliva, milk, and hair of nursing mothers in southeastern Iranian mothers: levels, distribution and risk assessment

This research is on lactating mothers in the city of Chah Bahar in Iran. This descriptive-analytical and questionnaire study selected a random sample of 80 mothers to examine mercury levels in their hair, milk, and saliva. The average concentration of mercury in milk, hair and saliva of mothers was 1.23 ± 0.48 µg/l, 1.81 ± 0.55 µg/g and 1.10 ± 0.63 µg/l, respectively. There was a significant correlation between mercury levels in mothers saliva and hair. Still, only a weak correlation was found between mercury levels in milk and hair, and milk and saliva, possibly associated with the high lipid content in milk. The number of children and length of the mother's pregnancy were related to the amount of mercury in the mother's milk. The number of teeth filled with amalgam, consumption of fish and marine products, consumption of fruit, and infant's weight at birth were also associated with the amount of mercury in breast milk. Chewing gum, fish consumption, infant's birth weight, weight, and length of pregnancy were among the factors associated with the amount of mercury in mothers' saliva. The mercury concentration in milk exceeded the WHO (1.4-1.7 µg/g) normal level in 8.5% mothers, and hair mercury was found in 12.5% mothers. It should be kept in mind that any amount of mercury can be harmful.

High lead contamination in Mother's breastmilk in Bihar (India): Health risk assessment of the feeding children

Lead poisoning in the recent times has caused serious health threats in the exposed human population. It is estimated that about 815 million people are exposed to lead poisoning worldwide and in India total 275 million children are exposed to blood lead contamination. The present study was carried outed in 6 districts of Bihar to know the extent of lead exposure in the children through their mother's breastmilk. The biological samples such as breastmilk, mother's urine, child's urine, and mother's blood samples were collected for quantitative lead estimation. Moreover, the selected household water sources (handpump) and the food consumed by the individuals-wheat, rice and potato samples were also collected for lead quantification. The study reveals that the breastmilk had high lead content in 92% of the samples (highest value 1309 μg/L), in blood presence of lead was observed in 87% studied samples (highest value 677.2 μg/L). In mother's urine the highest lead value was 4168 μg/L (62%) and in child's urine the highest value was 875.4 μg/L (62%) respectively of the studied samples. Moreover, in the studied food samples, wheat had lead content in 45% the studied samples (highest value 7910 μg/kg). In rice in 40% of the studied samples (highest value 6972 μg/kg) and in potato 90% of the studied samples (highest value = 13786 μg/kg) were found with elevated lead content respectively. The hazard quotient (HQ) and the cancer risk (CR) for lead contamination was very much higher in mothers followed by their children. The entire study indicated that lead exposure through food (wheat, rice and potato) has reached the mother's breastmilk and from their it has reached their child's body. This could cause serious hazards in the exposed children causing serious neurological damages, low IQ, low memory, and low mental growth in them. Therefore, a strategic action is required to control the present problem.

Lactational Exposure of Human Infants to Metal (loid)s: A Comparison of Industrial and Urban Inhabitants in North of the Persian Gulf

In this study, postnatal metal (loid)s (MLs) exposure was compared between the petrochemical and gas area of Asaluyeh (PGA) and urban area of Kaki (UA) in Bushehr province, Iran. Two hundred human breast milk (BM) samples from the industrial and urban areas were analyzed for MLs using Inductivity Coupled Plasma-Optical Emission Spectrometry (ICP-OES). Boron (B), copper (Cu), iron (Fe), and nickel (Ni) were found at the highest levels in both study areas. Adjusted multiple linear regression models revealed that the mean concentration of total MLs in BM samples collected from the PGA was statistically significantly greater than that of the UA (655.85 vs. 338.17 µg/L). Also, the mean concentrations of all detected MLs in BM samples collected from the PGA were statistically significantly higher than those collected from the UA. The hazard index (HI) of combined MLs in the PGA and UA illustrated non-cancer risk for infants. Lead (Pb) and chromium (Cr) in the PGA and Cr in the UA showed the risk of cancer. So it can be concluded that nursing infants from an industrial area are most at risk for MLs exposure during entire lactation course than those from an urban area.

Health risk assessments of heavy metals and trace elements exposure in the breast milk of lactating mothers in the Northeastern Iran

Mother's breast milk is a natural and complete food for infants but can be a main source of exposure to toxic pollutants. These pollutants can negatively affect the health of the infant. Therefore, conducting biomonitoring surveys is essential to evaluate such health effects in toxicological research. This study aimed to estimate the probable health risks for infants exposed to essential and non-essential trace elements through breast milk ingestion. This descriptive-analytical, cross-sectional study was performed on 90 breastfeeding mothers referred to the health centers in Mashhad, Iran in January 2021. The health risk assessments (carcinogenic and non-carcinogenic risk) were estimated using chronic daily intake (CDI), hazard quotient (HQ), hazard index (HI), and lifetime carcinogenic risk (CR), which were recommended by the US Environmental Protection Agency (US EPA). The results of the HQ values of trace elements through ingestion exposure for arsenic (90%), copper (90%), zinc (40%), and iron (10%) exceeded the threshold of HQ, and arsenic (66.59%), copper (16.91%), and zinc (9.68%) and iron (4.57%) had the highest contribution to increasing the HI index. The average value of CR was 5. 08 × 10-3. Chromium and iron showed significant relationships (P<0.05) with education level and disease background in this study, and the concentration of chromium, iron, and zinc in the breast milk samples significantly changed during lactation stages (P<0.05). Overall, the risk of carcinogenicity through exposure to breast milk for infants was higher than the safety level of US EPA risk. Therefore, there could be a potential health risk of trace elements, particularly arsenic, copper, and zinc for infants in Mashhad, Iran through the consumption of mothers' breast milk. More efforts are required to control and reduce routes of receiving trace elements in breastfeeding mothers by the competent authorities.

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.

Breastmilk cadmium levels and estimated infant exposure: a multicenter study of associated factors in a resource-limited country

BACKGROUND

Despite the undisputed benefits of breastfeeding, infants might become exposed to xenobiotics that could be excreted into breast milk following maternal exposure. This study was conducted to assess breastmilk cadmium levels among lactating women in Palestine, a resource-limited country. Estimated daily intake (EDI) of cadmium via breastmilk was also calculated and predictors of high breastmilk cadmium levels and high infant exposure via breastmilk were identified.

METHODS

This multicenter study was conducted using a descriptive-analytical design. The lactating women were recruited from different maternity and public health clinics in all regions of Palestine. Demographic variables and exposure to sources of cadmium were collected in an interviewer-administered questionnaire. Foremilk samples (about 5 mL) were collected in polyethylene tubes using the hand-expression technique. The breast milk samples were collected in the period between December 2020 and March 2021. A pre-validated method using inductively coupled plasma mass spectrometry (ICP-MS) was used to quantify breastmilk cadmium levels. EDI values were calculated from the quantified breastmilk cadmium levels.

RESULTS

Breastmilk samples were obtained from 256 lactating women. The mean breastmilk cadmium level was 0.34 (SD: 0.33) μg / L and the mean EDI of cadmium via breastmilk was 0.059 (SD: 0.058) µg / kg per body weight / day. Breastmilk cadmium levels were quantified in 92.6% of the breastmilk samples. Of the breastmilk samples, 13 (5.1%) had cadmium levels above those reported as "normal" by the World Health Organization (WHO). Multiple linear regression showed that higher breastmilk cadmium levels and higher EDI were predicted by being a smoker, living in a refugee camp, living close to an industrial area, living close to disposal of wastes, living close to paint shops, living in a house with peeling / chipping paint, frequent use of cosmetics, frequent use of hair dyes, and not using vitamins.

CONCLUSION

The breastmilk cadmium levels and infant exposure were predicted by maternal exposure to sources of cadmium. The findings reported in this study are valuable to antenatal and postnatal healthcare service providers. More studies are needed to plan and implement measures to reduce breastmilk cadmium levels and infants' exposure to cadmium via breastmilk.

Evaluation of some toxic metals in breast milk samples with dietary and sociodemographic characteristics: a case study of Kermanshah, Western Iran

This study aimed to investigate the concentration of some toxic metals (gold (Au), cadmium (Cd), chromium (Cr), mercury (Hg), nickel (Ni), lead (Pb), tin (Sn), and vanadium (V)) and arsenic (As) in breast milk based on demographic characteristics and the diet of mothers. In this cross-sectional study, 100 lactating mothers from Kermanshah, Western Iran, were included. The mean age of the participants was 29.5 (ranging from 16 to 43 years) with a mean BMI of 26.9 (± 3.81) kg (range: 17.0-39.1). The results of the pairwise correlation coefficient of trace elements illustrated that correlation was mostly positive and weak to moderate. A few exceptions of strong correlations were Cr-Ni (r = 0.82), Au-As (r = 0.64), Cr-V (r = 0.64), and Ni-V (r = 0.58). Moreover, results indicated that BMI (p = 0.008), cooking oil (0.042), and potato intake (p = 0.010) affected the trace element levels significantly. The concentrations of V (p = 0.044), Sn (p = 0.036), Au (p < 0.001), and As (p < 0.001) in the breast milk of women was affected by the BMI. The results of univariate linear regression analysis showed that the concentration of Pb in the milk of mothers who use cosmetics was significant (p < 0.05). Since the lifestyle of lactating women, such as cosmetics usage can impact the content of some elements in breast milk, they should be educated in this part.

The concentration and health risk of potentially toxic elements (PTEs) in the breast milk of mothers: a systematic review and meta-analysis

AIM

Breast milk is the best source of nutrition for a newborn during the first six months of his or her life. However there is a possibility that breast milk may contain pollutants such as metals. The current meta-analytic study assessed the concentration of potentially toxic elements (PTEs), including lead (Pb), cadmium (Cd), arsenic (As), Iron (Fe), Zinc (Zn), copper (Cu), and nickel (Ni), in mothers' milk.

METHOD

The literature studies regarding the concentrations of PTEs in the breast milk of mothers were collected from international databases such as PubMed, Scopus, Web of Science, and Embase. Afterward, the Total Target Hazard Quotient (TTHQ) by Monte Carlo Simulation (MCS) model was used to assess the non-carcinogenic risk.

RESULTS AND DISCUSSION

According to 42 of the 836 retrieved articles, the PTE concentrations in mother's milk were as follows: Cu (1.84 mg/kg) > Zn (1.80 mg/kg) > Fe (1.03 mg/kg) > Ni (0.60 mg/kg) > Pb (0.10 mg/kg) > As (0.15 mg/kg) ≈ Cd (0.15 mg/kg). Based on the containment type, the highest concentrations of As (2.80 mg/kg), Cd (0.07 mg/kg), and Pb (2.68 mg/kg) were related to Western Pacific Region (WPRO), European Region (EURO), and WPRO, respectively. In addition, for trace elements, Eastern Mediterranean Region (EMRO) was the region with the highest concentrations of Cu (3.56 mg/kg), Fe (2.78 mg/kg), Ni (3.13 mg/kg), and Zn (5.58 mg/kg) were related to Lastly, the non-carcinogenic risk assessment of the PTEs in breast milk indicated different risk patterns in various countries, and the calculated TTHQ level in infants was below 1.

CONCLUSION

Overall, human breast milk was generally safe for infants to consume and poses no risks to their health.

Exposure to multiple toxic metals and the risk of early embryonic arrest among women undergoing assisted reproductive techniques

BACKGROUND

Early embryonic arrest is a great challenge for in vitro fertilization. Whether exposure to toxic metals is associated with an increased risk of early embryonic arrest warrants investigation.

OBJECTIVES

Here, we conducted a case-control study in infertile women to estimate the associations between blood barium (Ba), arsenic (As), mercury (Hg), and lead (Pb) exposure levels and the risk of early embryonic arrest.

METHODS

Ba, As, Hg, and Pb exposure levels in fasting blood collected from 74 infertile women (123 cycles) with early embryonic arrest and 157 infertile women (180 cycles) without early embryonic arrest were measured by ICP-MS. Bayesian kernel machine regression (BKMR) was used to assess the association of exposure level of toxic metals mixture with the risk of early embryonic arrest as well as to evaluate which metal playing a leading role in the association, and then generalized estimating equations (GEEs) were used to evaluate the relationship between the selected harmful metal and the risk of early embryonic arrest. Finally, the potential causes of early embryonic arrest originating from the harmful metal exposure were explored.

RESULTS

Blood Ba levels were significantly higher in the case group than that in the control group (p = 0.009) rather than As, Pb and Hg. Results from BKMR showed that exposure to toxic metals mixture increased the risk of early embryonic arrest, with Ba playing a leading role (PIP = 0.9612). GEE analysis showed that high Ba exposure level was related with the increased risk of early embryonic arrest (p < 0.05) and it impacted on the oogenesis significantly.

CONCLUSIONS

Our study found that exposure to toxic metals mixture was associated with the increased risk of early embryonic arrest, and Ba contributed most to the increased risk. Higher Ba exposure in whole blood corresponds to a higher risk of early embryonic arrest and impacted on the oogenesis significantly.

Towards Development of Molecularly Imprinted Electrochemical Sensors for Food and Drug Safety: Progress and Trends

Due to their advantages of good flexibility, low cost, simple operations, and small equipment size, electrochemical sensors have been commonly employed in food safety. However, when they are applied to detect various food or drug samples, their stability and specificity can be greatly influenced by the complex matrix. By combining electrochemical sensors with molecular imprinting techniques (MIT), they will be endowed with new functions of specific recognition and separation, which make them powerful tools in analytical fields. MIT-based electrochemical sensors (MIECs) require preparing or modifying molecularly imprinted polymers (MIPs) on the electrode surface. In this review, we explored different MIECs regarding the design, working principle and functions. Additionally, the applications of MIECs in food and drug safety were discussed, as well as the challenges and prospects for developing new electrochemical methods. The strengths and weaknesses of MIECs including low stability and electrode fouling are discussed to indicate the research direction for future electrochemical sensors.

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 .

Concentrations and determinants of lead, mercury, cadmium, and arsenic in pooled donor breast milk in Spain

AIM

To measure concentrations of lead (Pb), mercury (Hg), cadmium (Cd), and arsenic (As) in longitudinally collected donor breast milk samples and to determine associated factors.

METHODS

Pb, Hg, Cd, and As concentrations were measured in 242 pooled breast milk samples from 83 donors to a Human Milk Bank in Spain, in 2015-2018, determining their association with the donors' sociodemographic profile, dietary and lifestyle habits, and post-partum time, among other factors, and with the nutritional characteristics of samples. Mixed-effect linear regression was used to identify predictors of Hg and As concentrations in breast milk and mixed-effect logistic regression to identify predictors of the presence of Pb and Cd.

RESULTS

As was the element most frequently detected in milk samples (97.1%), followed by Hg (81.2%), Pb (50.6%), and Cd (38.0%). Their median breast milk concentrations were 1.49 μg/L, 0.26 μg/L, 0.14 μg/L, and <0.04 μg/L, respectively. Concentrations of As were higher in breast milk from primiparous donors, while Hg was higher in donors with a greater intake of fatty fish and meat and lower in samples collected after a longer post-partum time and with higher lactose content. Detection of Pb was higher among multiparous donors, those gaining weight since before pregnancy, and ex-smokers and was lower in samples collected more recently and from donors with greater intake of red meat and eggs. Cd detection was higher for donors with university education and those with greater intake of fried and canned food and more frequent use of hand cream and was lower for donors with greater bread intake.

CONCLUSIONS

These findings reveal relatively high As concentrations, moderate Hg concentrations, and low Pb and Cd concentrations in pooled donor breast milk. Several factors including post-partum time, parity, smoking habit, and the intake of certain food items were associated with the metal content of milk samples.

Salivary Lead Levels among Workers in Different Industrial Areas in the West Bank of Palestine: a Cross-Sectional Study

Saliva is a biofluid that can easily be obtained and used for biomonitoring lead levels in occupationally and environmentally exposed individuals. The aims of this study were to determine salivary lead levels among workers in different industrial areas in the West Bank of Palestine and investigate the association between sociodemographic and occupational characteristics of the workers and their salivary lead levels. Salivary samples were obtained from workers in different industrial areas in metal-free polyethylene tubes. The samples were analyzed for their lead contents using a pre-validated inductively coupled plasma-mass spectrometric method. A total of 97 salivary samples were analyzed. The median salivary lead level was 1.84 μg/dL an IQR of 5.04 μg/dL. Salivary lead levels were significantly higher in workers who were 40 years and older (p value = 0.031), had 3 children or more (p value = 0.048), worked in repair workshops (p value = 0.012), worked in industrial areas for 20 years or more (p value = 0.048), did not consume fruits on regular basis (p value = 0.031), and smoked for 30 years or more (p value = 0.013). Multiple linear regression showed that smoking of 30 years old or more was a significant (p value < 0.001) predictor of higher salivary lead levels. Salivary lead levels among workers from different industrial areas of the West Bank were comparable to those occupationally exposed to lead in more industrialized and urbanized areas of the world. Smoking was a predictor of higher salivary lead levels.

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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Breast milk to blood lead ratios among women from the West Bank of Palestine: a cross-sectional study of associated factors

Background

Infants fed contaminated breast milk are at an increased risk of exposure to lead. Breast milk to blood (M/B) ratios have not been investigated among women in Palestine. The aim of this study was to assess blood, breast milk, and M/B lead ratios in samples collected from Palestinian breastfeeding women. Associations between sociodemographic characteristics with breast milk lead levels and M/B lead ratios were also investigated.

Methods

This study was conducted in a cross-sectional design in the period between October 2017 and April 2018. Breastfeeding women visiting maternity care centers in different regions of the West Bank of Palestine were recruited to the study by the nurses in the maternity care centers. Sociodemographic characteristics, venous blood, and breast milk samples were collected from each participant. Lead concentrations were analyzed using a validated inductively coupled plasma-mass spectrometric method. Mann–Whitney U test, Pearson’s Chi-square, Fisher’s exact, and Spearman’s correlations were used to analyze the data. Odds ratios (OR) were computed using a multivariate logistic regression model.

Results

Matching blood and milk samples were collected from 80 women. Lead concentrations in 11 (13.8%) of the breast milk samples were above the World Health Organization’s recommended levels. Breast milk lead levels were more likely to be ≥5 μg/L in breastfeeding women who lived in urban areas (aOR 4.96; 95% CI 1.10, 22.38) compared to those who lived in rural areas. Breast milk to blood lead ratios were more likely to be ≥25% in breastfeeding women who lived in urban areas (aOR 7.06; 95% CI 1.68, 29.77), used eye kohl (aOR 14.29; 95% CI 1.32, 155.06), and used hair dye (aOR 5.33; 95% CI 1.58, 18.00) compared to those who lived in rural areas, did not use eye kohl, and did not use hair dye, respectively.

Conclusions

Higher M/B lead ratios were predicted by living in urban areas, using eye kohl, and using hair dye. Decision makers in health authorities should address sources of exposure to lead in urban areas. Cosmetics containing lead should be assessed and regulated for lead content.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13006-021-00410-3.

Alternative matrices in forensic toxicology: a critical review

Purpose

The use of alternative matrices in toxicological analyses has been on the rise in clinical and forensic settings. Specimens alternative to blood and urine are useful in providing additional information regarding drug exposure and analytical benefits. The goal of this paper is to present a critical review on the most recent literature regarding the application of six common alternative matrices, i.e., oral fluid, hair, sweat, meconium, breast milk and vitreous humor in forensic toxicology.

Methods

The recent literature have been searched and reviewed for the characteristics, advantages and limitations of oral fluid, hair, sweat, meconium, breast milk and vitreous humor and its applications in the analysis of traditional drugs of abuse and novel psychoactive substances (NPS).

Results

This paper outlines the properties of six biological matrices that have been used in forensic analyses, as alternatives to whole blood and urine specimens. Each of this matrix has benefits in regards to sampling, extraction, detection window, typical drug levels and other aspects. However, theses matrices have also limitations such as limited incorporation of drugs (according to physical–chemical properties), impossibility to correlate the concentrations for effects, low levels of xenobiotics and ultimately the need for more sensitive analysis. For more traditional drugs of abuse (e.g., cocaine and amphetamines), there are already data available on the detection in alternative matrices. However, data on the determination of emerging drugs such as the NPS in alternative biological matrices are more limited.

Conclusions

Alternative biological fluids are important specimens in forensic toxicology. These matrices have been increasingly reported over the years, and this dynamic will probably continue in the future, especially considering their inherent advantages and the possibility to be used when blood or urine are unavailable. However, one should be aware that these matrices have limitations and particular properties, and the findings obtained from the analysis of these specimens may vary according to the type of matrix. As a potential perspective in forensic toxicology, the topic of alternative matrices will be continuously explored, especially emphasizing NPS.

Lead concentrations in breast milk of Moroccan nursing mothers and associated factors of exposure: CONTAMILK STUDY

The aim of CONTAMILK study was to estimate levels of contamination of breast milk (BM) of Moroccan nursing mothers by some xenobiotics including, lead (Pb), to identify associated factors of exposure and to determine the daily intake of newborns. Lead concentrations were determined in 70 samples of colostrum by ICPMS and a structured questionnaire was filled during milk collection to report participants' data. The median lead concentration was 908 μg/L (range 1.38-515,39 μg/L) and in 79 % of samples, levels were higher than the normal range reported by the World Health Organization (WHO) in BM (2-5 μg/L). Indeed, preterm delivery, frequency of use of cosmetic powders and lipsticks were significantly associated with the level of lead in BM. The estimated daily intake was greater than the tolerable daily intake (TDI) of the European food safety authority (0.5 μg/kg/day) for 39 babies and 6 babies according to the WHO (3.6 μg/kg/day).

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.

Determination of Aluminum, Chromium, and Barium Concentrations in Infant Formula Marketed in Lebanon

ABSTRACT

Infant formula is a major nutritional component for many infants and toddlers. However, the presence of contaminants, such as toxic metals, may pose increased health risks to infants. An investigation of the total concentrations of the metals aluminum (Al), barium (Ba), and chromium (Cr) in infant formulae marketed in Lebanon was performed. Powdered dairy and nondairy infant formula samples were collected from all commercially available brands (n = 39) in the Lebanese market on two production dates (78 samples in total) and analyzed for these three metals with inductively coupled plasma mass spectrometry. All brands contained detectable concentrations of Al and Ba, Cr was detected in 95% of brands. Mean (±standard deviation) concentrations of the metals were estimated as 1.54 ± 1.43 (Al), 0.256 ± 0.593 (Ba), and 0.168 ± 0.143 (Cr) (μg/g). The concentration ranges in the powdered formula were 0.080 to 7.93 (Al), 0.038 to 5.35 (Ba), and 0.041 to 0.348 (Cr) μg/g. A significant difference in the mean concentrations of Al, Ba, and Cr for the two production dates of a single brand was observed in 92, 59, and 83% of samples, respectively. The mean concentration of Al in the soy-based formula was significantly higher than that of aluminum in milk-based and corn-based formulas (P = 0.018). Cr concentrations in the continuation special formulations were significantly higher than those in the beginner formulations (P = 0.008). Our study provides the first publicly available information on metal contamination in infant formulas in Lebanon and reveals the need for frequent monitoring and surveillance of these products intended for infant consumption.

HIGHLIGHTS

Essential and toxic elements in human milk concentrate with human milk lyophilizate: A preclinical study

Concentrated human milk (HM-concentrate) can be obtained from the simple and inexpensive method of donated breast milk direct lyophilization. A previous study reported that HM-concentrate contains the adequate amount of main macro- and micronutrients for use as a nutritional resource for preterm infants with very low birth weight admitted to neonatal intensive care units. However, further details need to be elucidated about HM-concentrate composition, particularly its content of essential and potentially toxic trace elements. Therefore, this study aimed to determine the concentration of essential and toxic elements in human milk considered baseline (HM-baseline) and HM-concentrate, as well as to quantify changes in concentration of these elements after the HM concentration process. The concentration of Aluminum, Arsenic, Cadmium, Chromium, Iron, Mercury, Manganese, Nickel, Lead, Selenium, Tin, and Thallium was analyzed by inductively coupled plasma-mass spectrometry (ICP-MS). Moreover, Bayesian linear mixed effect models were applied to estimate the mean difference between HM-baseline and HM-concentrate samples. After comparison (HM-concentrate versus HM-baseline), a significant increase in concentration was observed only for Manganese (0.80 μg/L; 95% CrI [0.16; 1.43]) and Selenium (6.74 μg/L; 95% CrI [4.66; 8.86]), while Lead concentration (-6.13 μg/L; 95% CrI [-8.63; -3.61]) decreased. This study provides latest and reliable information about HM composition. After milk concentration by lyophilization, there was a significant increase only in the essential elements Manganese and Selenium. The essential micronutrient content in HM-concentrate was similar or higher than that in preterm mothers' milk, which suggests it is viable for nutritional support of preterm infants. In addition, the low concentrations of potentially toxic elements in HM-concentrate indicates that it is safe for consumption by premature newborns.

Selected elements and fatty acid composition in human milk as indicators of seafood dietary habits

The maternal diet and living environment can affect levels of chemical elements and fatty acid (FA) composition and their stable isotopes (δ¹³C_FA) in human milk. Information obtained from questionnaires is frequently imprecise, thus limiting proper associations between external and internal exposures as well as health effects. In this study, we focused on seafood as a source of potentially toxic and essential elements and nutritional FAs. Concentrations of selected elements in human milk (As, Cd, Cu, Mn, Pb, Se and Zn) were determined using inductively coupled plasma mass spectrometry (ICP-MS) and Hg using cold vapour atomic-absorption spectrometry (CV-AAS). The identification and quantification of FAs in maternal milk were performed by an in-situ trans-esterification method (FAMEs), and the characterization of FAMEs was performed by gas chromatography with a flame ionisation detector (GC-FID). δ¹³C_FA was determined by gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). Seventy-four lactating Slovenian women from the coastal area of Koper (KP), with more frequent consumption of seafood, and the inland area of Pomurje (MS), with less frequent seafood consumption, were included in this study. Along with basic statistical analyses, data mining approaches (classification and clustering) were applied to investigate whether FA composition and δ¹³C_FA could improve the information regarding dietary sources of potentially toxic elements. As and Hg levels in milk were found to be statistically higher in populations from KP than in those from MS, and 71% of individual FAs and 30% of individual δ¹³C_FA values in milk differed statistically between the studied areas. In 19 cases, the levels of FAs in milk were higher in KP than in MS; these FAs include C20:5ω3 and C22:6ω3/C24:1ω9, which are typically contained in fish. In 16 cases, the mean percentage of FAs was higher in MS than in KP; these FAs include the PUFAs C18:2ω6, C18:3ω3, and C20:4ω6 which are important for human and infant growth. The difference in δ¹³C levels of C10:0, C12:0, C14:0, C16:1, C16:0, C18:1ω9c, C22:6ω3, and δ¹³C 18:0-16:0 in the study groups was statistically significant. In all seven cases where δ¹³C of FA significantly differed between KP and MS, δ¹³C was higher in KP, indicating a higher proportion of a marine-based diet. The data mining approaches confirmed that the percentage of selected FAs (iC17:0, C4:0, C18:2ω6t, aC17:0, CLA, and C22:4ω6) and δ¹³C_FA of C18:1ω9c in human milk could be used to distinguish between high and low frequency of fresh seafood consumption.

Selenium status in lactating mothers-infants and its potential protective role against the neurotoxicity of methylmercury, lead, manganese, and DDT

A total of 206 lactating mothers and their infants (3-12 months) were included in this study to evaluate postnatal exposure to neurotoxic pollutants such as methylmercury (MeHg), lead (Pb), manganese (Mn), dichlorodiphenyltrichloroethane (DDT) and its metabolites [dichlorodiphenyldichloroethane (DDD), and dichlorodiphenyldichloroethylene (DDE)] and their association with delayed neurological development and to explore the protective role of selenium (Se) against chemical neurotoxicity. Neurodevelopmental performance was evaluated using Denver Developmental Screening Test II and Parents' Evaluation of Developmental Status (PEDS). Multivariate log-binomial regression modeling was applied for both single and multiple exposures to chemicals using a principal component analysis that generated six principal components. Both mothers and their infants had been exposed to metals and DDT metabolites, with some exceeding the accepted permissible limits. The geometric means of MeHg, Pb, Mn, DDD, DDE and DDT levels in breast milk were 1.333, 45.327, 15.576, 0.069, 0.542 and 1.08 μg/l, respectively. A single-exposure model identified a high risk of reduced PEDS performance significantly associated with DDD in breast milk [relative risk (RR) = 1.484; 95% confidence interval (95%CI) = 1.091-2.019] and marginally significantly associated with Pb in the mothers' blood (RR = 2.164; 95%CI = 0.87-5.382). We did not find a protective role of Se in neurodevelopment due to its high levels in the mothers. Models of multi-chemical exposure indicated that Mn in blood and breast milk, Se in blood and Pb in the mothers' urine were marginally significantly associated with a high risk of reduced PEDS performance (RR = 0.424; 95%CI = 0.176-1.022). The use of multi-chemical exposure approach in early life risk assessments is important because it indicates real-world exposure. Our results were not conclusive because the sample size was small, so future studies examining the implications to health of the impact of prenatal/postnatal exposure to a mixture of chemicals in the Saudi population are merited.

Concentration of mercury, cadmium, and lead in breast milk from Norwegian mothers: Association with dietary habits, amalgam and other factors

Mercury (Hg), cadmium (Cd), and lead (Pb) are of great concern for food safety and infants are especially sensitive to exposure to the maternal body burden. We quantified these elements in breast milk from Norwegian mothers and determined their association with dietary habits, maternal amalgam fillings, and smoking. Breast milk (n = 300) from the Norwegian Human Milk Study (HUMIS) was analyzed using triple quadrupole inductively coupled plasma mass spectrometry, after an acidic decomposition using microwave technique. We used multiple linear regression to examine predictors of Hg and Cd in breast milk, and logistic regression to test predictors of Pb above the quantification limit. The median breast milk concentrations (minimum - maximum) were 0.20 μg Hg/kg (<0.058-0.89), 0.057 μg Cd/kg (0.017-1.2), and <0.67 μg Pb/kg (<0.2-7.5). Cadmium showed no significant relation with any exposure variable investigated. Lead was associated with intake of liver and kidneys from game. For Hg concentration in breast milk, number of amalgam fillings and high fish consumption were significant predictors (p < 0.001). We detected a significant association (p < 0.01) between Hg in breast milk and maternal consumption of Atlantic halibut, lean fish, mussels and scallops and lifetime consumption of crab. Seafood intake alone explained 10% of variance, while together with amalgam explained 46% of variance in Hg concentration in breast milk. Our findings emphasize the importance of following consumer advice with respect to fish and seafood and points to amalgam as an important source for Hg exposure.

Impact of exposure to diesel exhaust during pregnancy on mammary gland development and milk composition in the rabbit

Exposure to fine-particulate air pollution is a major global health concern because it is associated with reduced birth weight and an increased risk of cardiovascular disease. Here we have investigated the potential for exposure to diesel exhaust during pregnancy to influence mammary gland development and milk composition. Female rabbits were therefore exposed by nose-only inhalation to either diluted diesel exhaust fumes (1 mg/m³) or clean air for 2h/day, 5 days/week, from the 3^rd to the 27^th days of pregnancy. On Day 28 of pregnancy, mammary glands were collected from twelve females (six controls and six diesel-exposed) and assessed for morphological and functional alterations. Milk samples were collected from eighteen dams (nine controls and nine diesel-exposed) during early (days 2 to 4) and established (days 13 to 16) lactation to verify the composition of fatty acids and major proteins and leptin levels. The mammary alveolar lumina contained numerous fat globules, and stearoyl CoA reductase expression was higher in mammary epithelia from diesel exhaust-exposed rabbits, which together suggested increased mammary lipid biosynthesis. Gas chromatography analysis of the composition of milk fatty acids revealed a sharp rise in the total fatty acid content, mainly due to monounsaturated fatty acids. Liquid chromatography-mass spectrometry analysis of milk samples enabled identification and quantification of the main rabbit milk proteins and their main phosphorylated isoforms, and revealed important changes to individual casein and whey protein contents and to their most phosphorylated isoforms during early lactation. Taken together, these findings suggest that repeated daily exposure to diesel exhaust fumes during pregnancy at urban pollution levels can influence lipid metabolism in the mammary gland and the lipid and protein composition of milk. As milk may contribute to metabolic programming, such alterations affecting milk composition should be taken into account from a public health perspective.