Dioxins/furans and PCBs in Canadian human milk: 2008-2011

Novel halogenated flame retardants in Canadian human milk from the MIREC study (2008-2011)

Novel halogenated flame retardants (NHFRs) have been developed to replace those brominated flame retardants that have been restricted due to their persistence, bioaccumulation potential and toxicity, therefore, it is important to determine whether these replacement products are present at detectable concentrations in Canadians. NHFRs were measured in human milk samples (n = 541) collected from across Canada between 2008 and 2011, which is the first pan-Canadian dataset for these chemicals in human milk. Among the 15 measured NHFRs and eight methoxy-polybrominated diphenyl ethers (MeO-PBDEs), nine NHFRs and two MeO-PBDEs (6-MeO-PBDE 47 and 2-MeO-PBDE 68) were detected at a frequency of more than 9%. Despite benzene, 1,1'-(1,2-ethanediyl)bis [2,3,4,5,6-pentabromo-]/decabromodiphenylethane [DBDPE] being detected less frequently than the other observed NHFRs, its relative contribution to the sum of nine NHFRs was important when it was present. The maximum ΣNHFR concentration in Canadian human milk was 6930 pg g-1 lipid while the maximum ΣMeO-PBDEs was 1600 pg g-1 lipid. While most NHFR concentrations were significantly correlated with each other, no relationships between maternal age, parity or pre-pregnancy BMI were identified with ΣNHFR concentrations in the milk. In contrast, maternal age was significantly correlated with ΣMeO-PBDE concentrations (r = 0.237, p < 0.001). ΣNHFR concentrations were similarly not related to maternal education, although ΣMeO-PBDE concentrations were found to be higher in milk from women who had graduated from trade schools relative to the other education levels considered. NHFR detection frequency and concentrations observed in the Canadian human milk seem to align well with Europe.

Cohort profile update: The Canadian Maternal-Infant Research on Environmental Chemicals Child Development study (MIREC-CD PLUS)

BACKGROUND

The pan-Canadian Maternal-Infant Research on Environmental Chemicals (MIREC) study was established to determine whether maternal environmental chemical exposures were associated with adverse pregnancy outcomes in 2001 pregnant women.

OBJECTIVES

The MIREC-Child Development (CD PLUS) study followed this cohort with the goal of assessing the potential effects of prenatal exposures on anthropometry and neurodevelopment in early childhood.

POPULATION

MIREC families with children between the ages of 15 months and 5 years who had agreed to be contacted for future research (n = 1459) were invited to participate in MIREC-CD PLUS which combines data collected from an online Maternal Self-Administered Questionnaire with biomonitoring and neurodevelopment data collected from two in-person visits.

PRELIMINARY RESULTS

Between April 2013 and March 2015, 803 children participated in the Biomonitoring visit where we collected anthropometric measures, blood, and urine from the children. The Behavioural Assessment System for Children-2, Behaviour Rating Inventory of Executive Function, MacArthur-Bates Communicative Development Inventories and the Communication subscale of the Adaptive Behaviour Scale from the Bayley Scales of Infant and Toddler Development-III are available on close to 900 children. There were 610 singleton children who completed in-person visits for neurodevelopment assessments including the Social Responsiveness Scale, Wechsler Preschool Primary Scale of Intelligence-III and NEuroPSYchological assessments (NEPSY). Currently, we are following the cohort into early adolescence to measure the impact of early life exposures on endocrine and metabolic function (MIREC-ENDO).

CONCLUSIONS

Data collection for the MIREC-CD PLUS study is complete and analysis of the data continues. We are now extending the follow-up of the cohort into adolescence to measure the impact of early life exposures on endocrine and metabolic function (MIREC-ENDO). MIREC-CD PLUS is limited by loss to follow-up and the fact that mothers are predominately of higher socioeconomic status and 'White' ethnicity, which limits our generalizability. However, the depth of biomonitoring and clinical measures in MIREC provides a platform to examine associations of prenatal, infancy and childhood exposures with child growth and development.

Historical production and release inventory of PCDD/Fs in China and projections upon policy options by 2025

Using the source identification and classification methodology described in UNEP standardized toolkit for dioxin releases, combined with research data over the past decade, the production and release of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) from 6 major sectors in China were inventoried from 2003 to 2020, and were projected until 2025 based on current control measures and relevant industrial plans. The results showed that after ratification of the Stockholm Convention, China's production and release of PCDD/Fs began to decline after peaking in 2007, demonstrating the effectiveness of preliminary control measures. However, the continual expansion of manufacturing and energy sectors, along with the lack of compatible production control technology, reversed the declining trend of production after 2015. Meanwhile, the environmental release continued to decrease, but at a slower rate after 2015. If subject to current policies, production and release would remain elevated with an expanding gap in between. This study also established the congener inventories, revealing the significance of OCDF and OCDD in terms of both production and release, and that of PeCDF and TCDF in terms of environmental impacts. Lastly, through comparison with other developed countries and regions, it was concluded that room for further reduction exists, but can only be achieved through strengthened regulations and improved control measures.

Polychlorinated dibenzo-p-dioxins and dibenzofurans and dioxin-like polychlorinated biphenyls in human milk from national human breast milk monitoring in 2016-2019 in China

Human breast milk monitoring programs were recommended to be carried out to assess human body burden to persistent organic pollutants and their temporal trends. Thus, we conducted a national survey during the period of 2016-2019 to determine PCDD/Fs and dl-PCBs in human breast milk from China. The total TEQ amounts in the upper bound (UB) was in the range of 1.97 to 15.1 pg TEQ g^-1 fat with a geometric mean (GM) of 4.50 pg TEQ g^-1 fat. 2,3,4,7,8-PeCDF, 1,2,3,7,8-PeCDD, and PCB-126 were more predominant contributors with the percentage contribution of 34.2 %, 17.9 %, and 17.4 %, respectively. By comparison with our previous monitoring results, the total TEQ in breast milk sample of the present study is statistically lower than that in 2011 with a reduction of 16.9 % in the average (p < 0.05), and comparable to that in 2007. The estimated GM of dietary intake of total TEQ for the breastfed was 25.4 pg TEQ kg^-1 body weight day^-1 that was higher than that of the adult. It is therefore worthy to make more efforts to reduce amounts of PCDD/Fs and dl-PCBs in breast milk and to continue monitoring to further observe if the amount of these chemicals continue to decrease.

Assessment of organohalogenated pollutants in breast milk from the Czech Republic

This biomonitoring survey brings new information on the occurrence of a total of 94 organohalogenated pollutants in 231 human breast milk samples collected in 2019 and 2021 from women living in two regions of the Czech Republic (Karvina and Ceske Budejovice). This study aimed to evaluate the concentrations of 6 indicator polychlorinated biphenyls (PCBs), 10 organochlorine pesticides (OCPs), 34 halogenated flame retardants (HFRs), 29 perfluoroalkyl and polyfluoroalkyl substances (PFAS) and 15 polychlorinated naphthalenes (PCNs). PCBs, OCPs, most of HFRs and PCNs were identified/quantified by gas chromatography coupled to (tandem) mass spectrometry (GC-MS(/MS)), while PFAS, hexabromocyclododecane isomers (HBCD), brominated phenols, and tetrabromobisphenol A (TBBPA) by ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). The mean value of the sum of the 6 indicator PCBs was 123.12 nanogram per gram of lipid weight (ng g^-1 lw). Hexachlorobenzene (HCB), β-hexachlorocyclohexane (β-HCH) and p,p'-dichlorodiphenyl-dichloroethylene (p,p'-DDE) were the most abundant OCPs, detected in 100 % (mean 11.8 ng g^-1 lw), 94.8 % (mean 6.1 ng g^-1 lw) and 100 % (mean 101.5 ng g^-1 lw) of samples, respectively. PCN congeners 20, 52 and 66 were detected in <1 % of the samples. The HFRs concentrations were relatively low compared to the levels of OCP; The detection rate of polybrominated diphenyl ethers (PBDEs, # 47, 99 and 153) ranged 21-68 % with a mean concentrations of 0.34 ng g^-1 lw - 0.42 ng g^-1 lw. PFAS concentrations were also low, with perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) dominant in this group (means of 22 pg ml^-1 and 21 pg ml^-1, respectively). Our results confirmed the long-term trend of declining levels of banned POPs in Czech mothers. The amounts of PCBs and OCPs were higher in older breastfeeding primiparous women.

Differences in mirex [dechlorane] and dechlorane plus [syn- and anti-] concentrations observed in Canadian human milk

As part of the pan-Canadian Maternal-Infant Research on Environmental Chemicals (MIREC) study, human milk samples were collected between 2008 and 2011, and analyzed for mirex, an organochlorine insecticide and flame retardant, in addition to dechlorane plus (syn- and anti-DDC-CO), the flame retardant replacement for mirex. Mirex was analyzed separately, using a method for the analysis of existing organochlorine insecticides, while the presence of DDC-CO isomers was determined using a method developed for the detection of emerging flame retardants. Mirex was detected in all samples analyzed (n = 298), while syn- and anti-DDC-CO were present in 61.0% and 79.5% of the samples, respectively (n = 541). Mirex concentrations have declined in human milk since the 1990s. Since this is the first pan-Canadian dataset reporting DDC-CO concentrations in human milk, no temporal comparisons can be made. Maternal age was correlated with concentrations of both compounds although parity did not impact concentrations of either analyte. Given the presence of this relatively recently identified flame retardant (DDC-CO) in human milk from women across Canada, studies to identify dominant sources of this compound are critical. Despite low concentrations of environmental chemicals in human milk from Canadian women, Health Canada supports breastfeeding of infants because of the important health benefits to both the mothers and their infants.

First WHO/UNEP survey of the current concentrations of persistent organic pollutants in human milk in Morocco

The presence of persistent organic pollutants (POPs) in human milk is an indicator of the level of these substances in the environment and enables evaluation of the potential exposure of breastfed children. POPs concentrations in a Moroccan human milk pooled sample (59 donors) were determined for the first time by the WHO reference laboratory to provide a baseline and allow monitoring of the future trends for those persistent organohalogen compounds. Eighty-one different POPs, including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and dioxins and furans (PCDD/Fs) were identified and quantified by using gas chromatography (GC) with an electron capture detector (ECD) and confirmed by gas chromatography-mass spectrometry (GC/LRMS). The obtained results showed that the sum of DDT (sum of o,p'-DDD, p,p'-DDD, o,p'-DDE, p,p'-DDE, o,p'-DDT, and p,p'-DDT) was 237.9 ng/g, representing 94.0% of all detected OCPs levels, with a dominance of p,p'-DDE, and p,p'-DDT. Cis-heptachlor epoxide, HCB, and HCH were found at much lower levels. PCB indicator level was 60.7 ng/g of lipid, with the dominance of PCB 138, PCB 153, and PCB 180, presenting 98.3% of the total. Among the 25 PBDE congeners quantified, BDE-47, BDE-153, BDE-197, and BDE-207 were the dominant congeners account for 15.4% of the total concentration of PBDE (1.3 pg/g lipid). The lipid-adjusted level of PCDD/Fs and dl-PCBs expressed in Toxic Equivalents (TEQs: 6.65 pg/g) were lower in comparison to those found in the other countries. In summary, detected POPs levels in Moroccan human milk were much lower compared to the other countries, reflecting the effectiveness of the compliance with Stockholm Convention requirements on eliminating or reducing emissions of selected POPs. Continued monitoring is needed for these compounds, for which this is the first data available, provided by the WHO/UNEP survey in Morocco.

Understanding the Chemical Exposome During Fetal Development and Early Childhood: A Review

Early human life is considered a critical window of susceptibility to external exposures. Infants are exposed to a multitude of environmental factors, collectively referred to as the exposome. The chemical exposome can be summarized as the sum of all xenobiotics that humans are exposed to throughout a lifetime. We review different exposure classes and routes that impact fetal and infant metabolism and the potential toxicological role of mixture effects. We also discuss the progress in human biomonitoring and present possiblemodels for studying maternal-fetal transfer. Data gaps on prenatal and infant exposure to xenobiotic mixtures are identified and include natural biotoxins, in addition to commonly reported synthetic toxicants, to obtain a more holistic assessment of the chemical exposome. We highlight the lack of large-scale studies covering a broad range of xenobiotics. Several recommendations to advance our understanding of the early-life chemical exposome and the subsequent impact on health outcomes are proposed.

Breastfed infants' exposure to polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins and dibenzofurans, and per- and polyfluoroalkyl substances: A cross-sectional study of a municipal waste incinerator in China

A municipal waste incinerator (MWI) in Zhejiang, China, operating since 2008 was completely reconstructed from 2016 to 2019. In 2013, we conducted a cross-sectional study of breastfeeding mothers living near the MWI. We evaluated the concentrations of polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the mothers' breast milk and their infants' estimated daily intake (EDI). To investigate the temporal variations of these pollutants, we conducted a cross-sectional study of 29 mothers in 2019. We assessed the levels of 18 PCB congeners, 17 PCDD/F congeners, and 21 per- and polyfluoroalkyl substance (PFAS) congeners in breast milk and estimated the EDI. The mean total concentrations of PCDD/Fs (ΣPCDD/Fs) and PCBs (ΣPCBs) were 81.2 and 4.90 ng/g lipid, respectively, while the toxic equivalent quantity (TEQ) levels of ΣPCDD/Fs and dioxin-like PCBs (ΣDL-PCBs) were 2.7 and 1.4 pg WHO-TEQ/g lipid, respectively. Compared to our 2013 measurements, the mass concentrations of ΣPCDD/Fs and ΣPCBs decreased by 13% and 35%, respectively (3.361 vs. 2.915 pg/g wet weight [ww] and 269.1 vs. 175.0 pg/g ww, respectively). The TEQ-ΣPCDD/F levels decreased by 67% (0.241 vs. 0.080 pg/g ww), but the TEQ-ΣDL-PCB levels increased by 11% (0.046 vs. 0.051 pg WHO-TEQ/g ww). The median concentration of PFASs was 0.250 ng/mL, ranging from 0.151 to 0.833 ng/mL. The infants' mean EDI of total PCDD/Fs and DL-PCBs was 17.7 pg TEQ/kg body weight [bw], representing a 20% decline compared to 2013. The average EDI levels of PFOS, PFOA, and PFNA were 5.8, 17.9, and 1.7 ng/kg bw, respectively. A comprehensive comparison of the results with studies from around the world showed that the potential health risks posed by legacy PCDD/F and PCB pollutants were not as grave for mothers and infants living near this MWI, but the emerging PFAS pollutants represented a new cause for concern. MAIN FINDINGS: The potential health risks posed by legacy PCDD/F and PCB pollutants were not particularly serious for mothers and infants living near the MWI, but the emerging PFAS pollutants raised new concerns.

Time trends of PCDDs, PCDFs, DL-PCBs, and NDL-PCBs in Italian women from biomonitoring studies

A number of biomonitoring investigations were carried out in Italy between 2000 and 2018 by the Unit of Human Exposure to Environmental Chemicals of the Italian National Institute of Health (Rome). The investigations were characterized by different features (case-control or cross-sectional studies, participants from impacted or no impacted areas, etc), but despite the differences, it was possible to study the time trends of Σ₇(PCDDs), Σ₁₀(PCDFs), Σ₁₂(DL-PCBs), and Σ₆(NDL-PCBs) (analytical and TEQ cumulative concentrations, as appropriate). All the chemicals considered showed clear rates of a time-dependent concentration decrease, data having previously been adjusted for the sampled Region and subject age. Σ₇(PCDDs) exhibited the fastest decrease with an average rate of -4.44 pg/g-fat year^-1 (2009-2018), whereas Σ₆(NDL-PCBs) was characterized by the slowest decrease with a rate of -0.771 ng/g-fat year^-1 (2000-2018). A clear distinction between the decreasing rates of Σ₇(PCDDs) and Σ₁₀(PCDFs) was observed, as the latter decreased at half the rate of the Σ7(PCDDs). The slower rate of the Σ₁₀(PCDFs) decline may be due to an ongoing source of PCDFs in the environment beyond those traditionally considered for this group of contaminants such as the production of PCDFs due to PCBs thermal conversion from matrices contaminated with PCBs. Production of PCDFs due to thermal conversion of matrices contaminated with PCBs could be an ongoing source which may be of concern because recent data have highlighted the diffusion of PCBs in the European environment. The decreasing rates of PCDDs + PCDFs, DL-PCBs, and PCDDs + PCDFs + DL-PCBs - original analytical data converted to "dioxin equivalents" - were respectively estimated as (pgTEQ/g-fat year^-1) -2.08, -2.06, and -2.10, values exhibiting good compatibility between one another.

Essential and Non-essential Trace Elements in Milks and Plant-Based Drinks

Although milk and plant-based drinks are widely consumed foodstuffs with high nutritional value, their consumption may also mean intake of non-essential/toxic elements becoming a risk for human health. This study was aimed at determining the concentrations of essential (Ca, Co, K, Mg, Mn, Na, Ni and P) and non-essential/toxic (Hg, Pb, U and V) elements in milks (cow and goat), plant-based drinks (soy, almond, rice and oat) and infant formulas from organic and conventional production systems. Lactose-free, fresh and ultra-high-temperature (UHT) milks were also included. Chemical analyses were performed by means of inductively coupled plasma-mass spectrometry (ICP-MS). The content of the elements hereby assessed did not depend on the production system and the presence of lactose. However, significant differences were found in the concentrations of multiple elements when comparing sterilization methods, source (animal vs. plant-based) and animal species. Non-essential elements were not detected in milks and plant-based drinks, excepting Pb, which was detected in three samples. While the consumption of goat milk is recommended, considering the global intake of essential elements and the absence of non-essential elements, further studies should be conducted to confirm the absence of non-target toxic elements at very low trace levels. On the other hand, the best plant-based drinks are those made up with almonds (intake of Ca) and soy (K and Mg). The current results should be useful to help the population to balance the benefits and risks from milks and plant-based drinks consumption, as well as to adapt their dietary habits.

Perfluorinated alkyl substances in Canadian human milk as part of the Maternal-Infant Research on Environmental Chemicals (MIREC) study

Perfluorinated alkyl substances (PFAS) were determined in human milk samples (n = 664) from participants in the Maternal-Infant Research on Environmental Chemicals (MIREC) study. ΣPFAS concentrations (sum of seven PFAS) ranged from 3.1 ng L^-1 to 603 ng L^-1, with a median concentration of 106 ng L^-1 in the Canadian mothers' milk analyzed. These data comprise the first pan-Canadian dataset of PFAS in human milk. Perfluorooctanoic acid (PFOA) and linear perfluorooctanesulfonate (L-PFOS) were the dominant contributors to ΣPFAS in human milk samples. An inverse relationship between ΣPFAS concentrations and age was observed (Spearman correlation - 0.184). Primiparous women had elevated PFAS concentrations in milk relative to women who had children previously (p < 0.001). In contrast, the region of maternal birth did not influence ΣPFAS concentrations (p = 0.156). Although China and Norway have observed consistently detectable levels of perfluoroundecanoic acid (PFUdA) in human milk, PFAS with long carbon chains (n ≥ 11) were not present above method detection limits in Canadian human milk samples analyzed as part of the MIREC study. In conclusion, despite the presence of low levels of environmental contaminants in human milk, Health Canada supports breastfeeding due to the benefits to both infants and mothers.

Accumulation characteristics of polychlorinated dibenzo-p-dioxins and dibenzofurans and polychlorinated biphenyls in human breast milk from a seaside city of North China

Breast milk samples were collected from 51 mothers in a seaside city Dalian, where the residents usually have higher dietary exposure to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) due to the larger consumption of seafood. The lipid-basis concentrations of ∑Cl_2-8DD/Fs, ∑Cl_2-10Bs, and total toxicity equivalent (WHO-TEQ) were measured to be in the ranges of 35.7-2727.8 pg/g, 4.91-52.64 ng/g, and 2.27-36.30 pg/g, respectively. The average proportion of ∑Cl_2-3DD/Fs was higher than that of ∑Cl_4-7DD/Fs in the collected human breast milk samples, suggesting that the health risk of Cl_2-3DD/Fs should be especially concerned. The concentration data of PCDD/Fs and PCBs in human breast milk essentially followed a positive skew probability distribution. Women in high-level exposure scenarios exhibited a higher potential to accumulate homologues Cl₄DFs, Cl₇DFs, Cl₈DF, and Cl₆Bs in breast milk. Three PCDD/F congeners (1,2,3,6,7,8-Cl₆DF, 1,2,3,4,7,8-Cl₆DF, and 1,2,3,4,6,7,8-Cl₇DD) and three PCB congeners (PCB 126, PCB 138, and PCB 169) were identified as good indicators for the accumulation of PCDD/Fs and PCBs in human breast milk, respectively. The food-to-milk accumulation factors (FMAF) were calculated to evaluate the accumulation potentials of different PCDD/F and PCB congeners in human breast milk via dietary exposure. The calculated FMAF value presented a non-monotonic variation with the logarithm of n-octanol-water partition coefficient (log K_OW) with a peak at a log K_OW value of about 7.3 and a valley at a log K_OW value of about 8. The mean value of the estimated daily intake (EDI) of total WHO-TEQ for breast-fed infants in Dalian, predicted by Monte Carlo simulation, was 10 folds higher than the upper range of the tolerable daily intake (TDI) value (4 pg WHO-TEQ/kg bw/d), suggesting continued and enhanced efforts should be made to reduce the exposure risk of infants to PCDD/Fs and PCBs.

Persistent Organic Pollutants in Human Milk: Exposure Levels and Determinants among Lactating Mothers in Lebanon

ABSTRACT

Exposure of newborns to persistent organic pollutants (POPs) is a public health concern. The objective of this study was to assess the prevalence of POPs in human milk collected from lactating mothers in Lebanon and to investigate the sociodemographic, nutritional, and other lifestyle determinants. Fifty-four breast milk samples were collected as per World Health Organization guidelines. A survey was used to assess the anthropometric and demographic characteristics of participants. Dietary habits were evaluated based on a semiquantitative food frequency questionnaire. Organochlorine pesticides and polychlorinated biphenyls were measured in milk samples with liquid-liquid extraction and gas chromatography. Among the screened POPs, dichlorodiphenyldichloroethylene (DDE) was the only POP detected in breast milk samples and was found in only 17.9% of the samples, with a mean (SD) of 11.6 (5.0) μg/L and a range of 5.7 to 21.4 μg/L. Prepregnancy body mass index and age were positively associated with DDE contamination in breast milk. Women who consumed cereals at least two times per week had detectable DDE contamination in their breast milk. Consumption of potatoes and beans at least once per week was also associated with DDE contamination. Our study is the first to assess the presence of POPs in breast milk in Lebanon. The benefits of breastfeeding compensate for the low prevalence of DDE in the breast milk. Our findings highlight the high need to implement monitoring policies, good agricultural practices, and education programs for breastfeeding mothers.

HIGHLIGHTS

Organohalogens: A persisting burden in Slovenia?

Persistent organic pollutants (POPs) represent a concern for the environment and human health due to their persistence and toxicity. Exposure in Slovenia is geographically differentiated because the country, as part of former Yugoslavia, has a history of industry and regional contamination and is - at the same time - known for its clean nature. The PCB pollution of the Krupa River drew the public's attention to the chemical burden of Slovenians, and the demand for studies has been rising since. We assessed the exposure of men (n = 548) and primiparous women (n = 536) to POPs in 12 regions of Slovenia as well as exposure pathways via questionnaires. Most PCDD/Fs, PCBs, and PBDEs could be determined in pooled samples of maternal milk at low concentrations (1.57 pg/gTEQ, 1.47 pg/gTEQ, and 1076 pg/g fat, respectively), but a much lower number of compounds could be measured above the LOQ in pooled men's plasma samples (PCDD/Fs 0.08 pg/gTEQ, PCBs 0.007 pg/gTEQ, ΣPBDE 920 pg/g), and only HCB, p,p'-DDE, ΣDDT, and the non-dioxin-like PCB congeners 138, 153, and 180 could be determined in individual samples of milk (concentration range 5-60 ng/g fat). In individual samples of men's serum, only p,p'-DDE and ΣPCB were detected at concentrations of 0.25 ng/g and 0.3 ng/g, respectively. Nonetheless, we were able to differentiate between polluted and unpolluted areas on a national level, with higher exposure levels in the PCB polluted region of Bela Krajina, the industrial region Zasavje, and the capital, Ljubljana. Despite low concentrations, determinants of exposure, such as age, proximity to roads, old building materials, private water supplies, and consumption of alcohol, fish, meat, and eggs that have previously been observed only at higher levels could still be identified. Furthermore, levels of PCBs and PBDEs were highly correlated suggesting common exposure sources and pathways, whereas PCDD/Fs were correlated to a lesser extent. The calculated ratio between DDT and DDE in maternal milk samples was decreasing with the year of sampling, suggesting no ongoing exposure to DDT. The study findings suggest low exposure of men and lactating women to legacy pollutants in Slovenia, which gave rise to the hypothesis that Slovenia's geographical location might provide shelter from the long-range transport of POPs via Westerly winds. This hypothesis remains to be confirmed within future studies.

Are temporal trends of some persistent organochlorine and organobromine compounds in Swedish breast milk slowing down?

We investigated body burdens of persistent organic pollutants (POPs) in Swedish first-time mothers by measurements in breast milk, and followed up the temporal trends between 1996 and 2017. POPs were analysed in individual samples (n = 539) from participants from Uppsala county, Sweden. This made it possible to adjust temporal trends for age of the mother, pre-pregnancy BMI, weight gain during pregnancy, weight loss after delivery, and education, the main determinants for POP body burdens, apart from sampling year. We also compared observed body burdens with the body burdens determined to be safe from a health perspective in the risk assessment of dioxin-like polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), published by the European Food Safety Authority (EFSA). Declining temporal trends in breast milk of on average -4 to 14% per year were observed 1996-2017 for PCBs, PCDD/Fs, chlorinated pesticides, and brominated flame retardants, except for the polybrominated diphenyl ethers (PBDEs) BDE-153 and BDE-209. The toxic equivalents (TEQs) for PCDD declined faster than PCDF TEQs, -6.6% compared to -3.5% per year. For CB-169, CB-180, PCDDs, PCDFs, Total TEQ, and hexachlorobenzene (HCB), a change point year (CP) was observed around 2008-2009 and after that, the decline in levels has slowed down. If breast milk levels follows the exponential declining trend of total TEQ estimated for the entire period (-5.7% per year), 97.5% of first time mothers from the Uppsala area will have body burdens below the estimated safe level in year 2022. If instead it follows the estimated % decline after the CP in 2008 (-1.6% per year), it will take until 2045 before 97.5% is below the estimated safe level. It is important to proceed with the monitoring of POPs in breast milk from Swedish mothers in order to further observe if the levels are stabilizing or continue to decline.

Exposure and risk assessment of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs) for primiparous mothers and breastfed infants in Penang, Malaysia

An average 50 ml breast milk samples were collected from 21 lactating primiparous mothers (range 25 to 45 years, mean 33 years), 4-8 weeks after delivery in Penang Island, Malaysia. The geometric mean concentration of the most toxic congeners, 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) was 0.14 pg WHO₂₀₀₅-TEQ g^-1 zlipid. The most abundant congeners of PCDD/Fs were octachlorodibenzo-p-dioxin (OCDD) (5.9-75.4%), followed by 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin (1,2,3,4,6,7,8-HpCDD) (1.1-30.7%). The geometric mean level of total dioxins and dl-PCBs was 2.2 pg WHO₂₀₀₅-TEQ g^-1 lipid, significantly lower than those in developed countries or highly contaminated areas. The total dioxins and dl-PCBs in pg WHO₂₀₀₅-TEQ levels in breast milk were significantly correlated with years of residence at potential contaminated site. The average daily intake of 11.8 pg WHO₂₀₀₅-TEQ kg^-1 body weight was estimated for a breastfed infant at 6 months of age. This demonstrates the exposure risk to infants, especially from Penang region, to these pollutants from human milk intake are potentially high during the lactation period.

Multiple persistent organic pollutants in mothers' breastmilk: Implications for infant dietary exposure and maternal thyroid hormone homeostasis in Uganda, East Africa

Persistent organic pollutants (POPs) are ubiquitous contaminants with adverse health effects in the ecosystem. One of such effects is endocrine disruption in humans and wildlife even at background exposure concentrations. This study assessed maternal breastmilk concentrations of POPs; brominated flame retardants (BFRs), polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs), and the potential health risks posed to the nursing infants. We also evaluated the association of these POPs with total 3,3',5-triiodo-L-thyronine (T₃), L-thyroxine (T₄), and 3,3',5'-triiodo-L-thyronine (rT₃) levels measured in human breast milk. Thirty breastmilk samples were collected from Kampala, Uganda between August and December 2018. Hexabromobenzene was not detected while the maximum level of 2,2',4,4',5,5'-hexabrombiphenyl was 64.7 pg/g lw. The median levels of total indicator PCBs, PBDEs, dioxin-like PCBs, and PCDD/Fs in the samples were 159 pg/g lw, 511 pg/g lw, 1.16 pg TEQ/g lw, and 0.4 pg TEQ/g lw, respectively. These levels were lower than those reported in other countries. Owing to their bio accumulative nature, PCBs -81, -169, and ∑PCDD/Fs increased with increase in maternal age. Estimated dietary intakes for dioxin-like PCBs and PCDD/Fs were lower than those reported elsewhere but were higher than the WHO tolerable daily intakes suggesting potential health risks to nursing infants. In adjusted single pollutant models, PCB-126, PCB-169, and ∑PCB_TEQ were negatively associated with T₃, while 1,2,3,4,5,7,8-HpCDF was positively associated with rT₃. Although these associations did not persist in multipollutant models, our findings suggest potential thyroid hormone disruption by POPs in mothers. This may reduce the levels of thyroid hormones transferred from the mother to the neonates and, hence, adversely influence infant growth. A temporal study with a bigger sample size is required to corroborate these findings.

GC-MS Analysis of Phthalates and Di-(2-thylhexyl) Adipate in Canadian Human Milk for Exposure Assessment of Infant Population

BACKGROUND

Although more information has become available on the occurrence of phthalates and di(2-ethylhexyl) adipate (DEHA) in foods including cow's milk, information on their presence in human milk, the important and recommended sole diet for infants up to six months of age, is very limited, especially for DEHA.

OBJECTIVE

To develop a GC-MS method for simultaneous analysis of DEHA and phthalates in human milk samples and generate occurrence data for exposure assessment.

METHOD

Human milk samples were extracted with acetonitrile followed by dispersive solid-phase extraction and GC-MS analysis.

RESULTS

Among the 305 human milk samples collected from the Canadian Maternal-Infant Research on Environmental Chemicals Study, some phthalates (DHxP, BBzP, and DOP) were not detected in any of the samples, while DEHA and the other phthalates (DMP, DEP, DBP, DiBP, and DEHP) were detected at low frequencies with levels from 30.4-237 ng/g in up to 31 of the 305 human milk samples.

CONCLUSIONS

In general, DEHA and phthalates were detected at low frequencies and low levels in the 305 human milk samples.

HIGHLIGHTS

A GC-MS method based on dispersive solid phase extraction was developed for analysis of DEHA and eight phthalates in 305 human milk samples for exposure assessment.

Pollutants in Breast Milk: A Public Health Perspective - A Commentary of the Nutrition Committee of the French Society of Pediatrics

Pregnant and lactating women are continuously and ubiquitously exposed to numerous environmental pollutants from various sources including air, food, water, and occupational and household environments. The available evidence shows that pollutants are present in human milk and one of the emerging questions is what happens when the nursing infant is involuntarily exposed to contaminants through breastfeeding.The available literature does not currently provide a conclusive evidence of any consistent or clinically relevant health consequences in infants exposed to environment chemicals through breast milk. The available data strongly suggest that the benefits of breastfeeding outweigh the potential harmful effects of pollutants contained in human milk. The committee of nutrition of the French Pediatric Society strongly supports breastfeeding but also calls for public health actions to reduce the overall contamination level in the environment, to continue promoting breastfeeding, and to support research in this area.

Levels and profiles of persistent organic pollutants in breast milk in China and their potential health risks to breastfed infants: A review

Although some persistent organic pollutants (POPs) were prohibited or limited in use several decades ago, they are still frequently detected in the human body. The purpose of this study was to understand the levels and profiles of POPs in breast milk in China and assess their potential health risks among breastfed infants under six months of age. A literature review focused on China was performed for studies published from 2001 to 2020. The POP levels in breast milk along with other important variables were extracted, and then the average individual POP levels in breast milk were estimated. This review summarises the distribution of traditional and new POPs, including polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), legacy brominated flame retardants (BFRs), perfluorinated compounds (PFCs), and chlorinated paraffins (CPs) and reported notably high levels of short-chain chlorinated paraffins and 1,1-dichloro-2,2-bis (p-chlorophenyl) ethylene (p,p'-DDE) in breast milk. Although the levels of traditional POPs generally declined over time, especially p,p'-DDE and beta-hexachlorocyclohexane (β-HCH), women living in coastal areas, urban areas, and southern China still have a high body burden of certain POPs. In the present study, the estimated daily intake (EDI) of POPs through breastfeeding was used to evaluate the health risk for infants by comparing with acceptable levels. The findings suggested that infants born in coastal areas most likely suffered potential health risk from exposure to DDT, and the health risk of hexachlorobenzene (HCB) in infants in most nationwide regions remains a concern. More importantly, the EDI of PCBs for infants exceeds the safe limit on a national scale. Continuous surveillance of PCBs in breast milk is critical to evaluate the potential health effects on humans.

Biomonitoring of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in human milk: Exposure and risk assessment for lactating mothers and breastfed children from Spain

The main objective of the present research was to evaluate the levels of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (dl-PCBs) in the human milk of Spanish lactating women who participated in the BETTERMILK project so that exposure and risk could be assessed for these mothers and their breastfed children. The total ∑PCDD/Fs + dl-PCBs TEQ₂₀₀₅ concentrations in the upper-bound (UB) ranged from 1.29 to 13.48 pgTEQ₂₀₀₅ g^-1 lipid. The estimated geometric mean level for the sum of PCDD/F and dl-PCBs was 4.10 and 4.42 pgTEQ₂₀₀₅ g^-1 lipid, lower-bound (LB) and UB respectively and were below the reference level reported by EFSA, which is associated with adverse effects in boys of 9 years and related to lactating mothers' exposure values of the tolerable weekly intake (TWI) of around 2 pgTEQ₂₀₀₅ kg^-1 bw per week. Nevertheless, it was exceeded when the 95th percentile (8.31 pgTEQ₂₀₀₅ g^-1 lipid, as UB) was considered. Results from a multiple regression analysis showed that age has a significant impact on milk ∑PCDD/Fs + dl-PCBs levels, with higher concentrations observed in the milk from older mothers.

Lactational exposure to polychlorinated biphenyls is higher in overweight /obese women and associated with altered infant growth trajectory: A pilot study

•

Human milk levels of PCBs are higher in mothers with overweight and obesity.

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Lactational exposure to PCBs is associated with alterations in development.

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Lactational expsures to PCBs in human milk are associated with slower infant growth patterns.

Background

Infant exposure to environmental chemicals, such as polychlorinated biphenyls (PCBs), may contribute to developmental programming of long-term metabolic disease risk. PCBs persist given their lipophilicity and long half-lives, allowing them to bio-accumulate in adipose tissue. These compounds can then be excreted into maternal milk resulting in infant exposure.

Objective

To determine the level of PCBs in milk from mothers with pre-pregnancy overweight and obese (OW/OB) versus normal weight status (NW) and evaluate the association of milk PCB levels with infant growth over the first 6 months of life.

Methods

A pilot study of a subset of milk samples from mothers with NW (pre-pregnancy body mass index (BMI) < 25 kg/m², n = 11) and OW/OB (pre-pregnancy BMI ≥ 25 kg/m², n = 8) were examined approximately 2-weeks postpartum. PCB congeners 138 + 163, 132 + 153, 180, and the sum were measured using gas chromatography/mass spectrometry and adjusted for milk fat content. Infant growth was monitored from birth to 6 months for weight-for-age (WFA), length-for-age (LFA), weight-for-length (WFL), head circumference-for-age (HCA), and associations with milk PCB content determined using linear mixed modeling.

Results

Total milk fat content did not differ by maternal weight status (p = 0.88). Milk from mothers with OW/OB had significantly higher PCB sum (p = 0.02) and PCB 138 + 163 (p = 0.03). PCB 132 + 153 (β −0.0008, p = 0.0218), PCB 180 (β −0.0010, p = 0.0279), and PCB sum (β −0.0006, p = 0.0138) were negatively associated with HCA Z-score growth to 6 months. PCB 180 was negatively associated with infant WFA (β −0.0015, p = 0.0058) and WFL Z-score (β −0.0016, p = 0.0263) to 6 months. There were no associations of PCB sum content with WFL, LFA, WFL Z-score over the first 6 months of life.

Conclusions

Maternal overweight and obesity are associated with higher levels of total PCB congeners (132, 138, 153, 163, 180) in human milk. PCB congeners have negative associations with infant head circumference and weight trajectory over the first 6 months of life.

The influence of sex, genotype, and dose on serum and hippocampal cytokine levels in juvenile mice developmentally exposed to a human-relevant mixture of polychlorinated biphenyls

Polychlorinated biphenyls (PCBs) are pervasive environmental contaminants implicated as risk factors for neurodevelopmental disorders (NDDs). Immune dysregulation is another NDD risk factor, and developmental PCB exposures are associated with early life immune dysregulation. Studies of the immunomodulatory effects of PCBs have focused on the higher-chlorinated congeners found in legacy commercial mixtures. Comparatively little is known about the immune effects of contemporary, lower-chlorinated PCBs. This is a critical data gap given recent reports that lower-chlorinated congeners comprise >70% of the total PCB burden in serum of pregnant women enrolled in the MARBLES study who are at increased risk for having a child with an NDD. To examine the influence of PCBs, sex, and genotype on cytokine levels, mice were exposed throughout gestation and lactation to a PCB mixture in the maternal diet, which was based on the 12 most abundant PCBs in sera from MARBLES subjects. Using multiplex array, cytokines were quantified in the serum and hippocampus of weanling mice expressing either a human gain-of-function mutation in ryanodine receptor 1 (T4826I mice), a human CGG premutation repeat expansion in the fragile X mental retardation gene 1 (CGG mice), or both mutations (DM mice). Congenic wildtype (WT) mice were used as controls. There were dose-dependent effects of PCB exposure on cytokine concentrations in the serum but not hippocampus. Differential effects of genotype were observed in the serum and hippocampus. Hippocampal cytokines were consistently elevated in T4826I mice and also in WT animals for some cytokines compared to CGG and DM mice, while serum cytokines were usually elevated in the mutant genotypes compared to the WT group. Males had elevated levels of 19 cytokines in the serum and 4 in the hippocampus compared to females, but there were also interactions between sex and genotype for 7 hippocampal cytokines. Only the chemokine CCL5 in the serum showed an interaction between PCB dose, genotype, and sex. Collectively, these findings indicate differential influences of PCB exposure and genotype on cytokine levels in serum and hippocampal tissue of weanling mice. These results suggest that developmental PCB exposure has chronic effects on baseline serum, but not hippocampal, cytokine levels in juvenile mice.

PCDD/F levels and phase distributions in a full-scale municipal solid waste incinerator with co-incinerating sewage sludge

Co-incinerating sewage sludge in municipal solid waste incinerators (MSWIs) is an up-to-date disposal way with great prospects to market. To verify the environmental safety of this disposal method, a field study was conducted in a MSWI which has achieved PCDD/Fs ultra-low emission. PCDD/F phase partitioning characteristics, congener profiles, and the influence of selective catalytic reduction (SCR) were also investigated. PCDD/F emission levels ranged from 0.0031 to 0.0053 ng I-TEQ/Nm³, distinctly lower than the national standard. For tests co-incinerating 5% sludge, PCDD/F emission levels were averagely 32% lower than tests mono-combusting municipal solid waste. The phase partitioning study found that PCDD/Fs enriched in condensed water took a non-negligible proportion of the total concentration in flue gas. The removal efficiency of SCR in tests co-incinerating sludge was averaged at 41.9%. However, in tests without adding sewage sludge, PCDD/F concentrations in flus gas after SCR were increased. It was found that the elevations were mainly attributed to the increase of low-chlorinated PCDF congeners in gas-phase. By inference, memory effect existing in SCR might be responsible for the increase of PCDD/F levels. PCDD to PCDF ratios in most of the sampling points were >1, suggesting that de novo synthesis is not the dominant formation pathway in the studied incinerator. This study verified that co-incinerating sewage sludge in the MSWI would not elevate the emission levels of PCDD/Fs. If all of the yielded municipal waste is incinerated with adding 5% sewage sludge, more than half of sewage sludge can be disposed safely in Shenzhen.

Screening of human health risk to infants associated with the polychlorinated biphenyl (PCB) levels in human milk from Punjab Province, Pakistan

This study assessed the polychlorinated biphenyl (PCB) levels in human milk and its associated health risk to infants from rural and urban settings of five districts of Punjab Province, Pakistan. The ∑₃₄PCB concentrations ranged from 30.9 to 68.3 ng g^-1 on lipid weight (l.w.) basis. The ∑₈DL-PCB concentrations were ranged from 0.29 to 1.35 ng g^-1 l.w., (mean 6.2 ± 8.7 ng g^-1 l.w.), with toxicity equivalent to polychlorinated dibenzodioxins (PCDDs) ranging from 8.58 × 10^-6 to 0.05 ng TEQ g^-1 l.w. The spatial trend of PCB levels in human milk revealed higher bioaccumulative levels for urban mothers as compared with rural counterparts. The estimated daily intake (EDI) values of DL-PCBs to infants through trans-mammary transfer were considerably higher than tolerable daily intake limits established by WHO (i.e., 1-4 pg TEQ kg^-1 bw) and other globally recognized organizations. Similarly, the hazard quotient values for TEQ ∑₈DL-PCBs (range 1.21 to 79.87) were far above the benchmark value of 1 at all the sampling sites, indicating the high levels of adverse health risks to infants in the region through breast milk consumption. The ∑₃₄PCB levels were found to be negatively correlated with mother' age (r = -0.31; p = 0.02), parity (r = - 0.85; p = 0.001), and infant' birth weight (r = - 0.73; p = 0.01). The present study suggests undertaking comprehensive public health risk assessment studies and firm regulatory measures to safeguard human health risks.

Human Pluripotent Stem Cells: A Unique Tool for Toxicity Testing in Pancreatic Progenitor and Endocrine Cells

Diabetes prevalence is increasing worldwide, and epidemiological studies report an association between diabetes incidence and environmental pollutant exposure. There are >84,000 chemicals in commerce, many of which are released into the environment without a clear understanding of potential adverse health consequences. While in vivo rodent studies remain an important tool for testing chemical toxicity systemically, we urgently need high-throughput screening platforms in biologically relevant models to efficiently prioritize chemicals for in depth toxicity analysis. Given the increasing global burden of obesity and diabetes, identifying chemicals that disrupt metabolism should be a high priority. Pancreatic endocrine cells are key regulators of systemic metabolism, yet often overlooked as a target tissue in toxicology studies. Immortalized β-cell lines and primary human, porcine, and rodent islets are widely used for studying the endocrine pancreas in vitro, but each have important limitations in terms of scalability, lifespan, and/or biological relevance. Human pluripotent stem cell (hPSC) culture is a powerful tool for in vitro toxicity testing that addresses many of the limitations with other β-cell models. Current in vitro differentiation protocols can efficiently generate glucose-responsive insulin-secreting β-like cells that are not fully mature, but still valuable for high-throughput toxicity screening in vitro. Furthermore, hPSCs can be applied as a model of developing pancreatic endocrine cells to screen for chemicals that influence endocrine cell formation during critical windows of differentiation. Given their versatility, we recommend using hPSCs to identify potential β-cell toxins, which can then be prioritized as chemicals of concern for metabolic disruption.

Polybrominated diphenyl ethers in mothers' breast milk and associated health risk to nursing infants in Uganda

The aim of this study was to investigate levels of polybrominated diphenyl ethers (PBDEs) in breast milk samples from healthy primiparous mothers who had lived in Kampala capital city (urban area) and Nakaseke district (a rural area) for the last five years. Fifty samples were collected between March and June 2018 and were extracted by dispersive solid-phase extraction (SPE). Clean-up was performed on an SPE column and analysis was done using gas chromatography-mass spectrometry. Total (∑) PBDEs (BDE 28, 47, 49, 66, 77, 99, 100,138,153, 154, 183 and 209) ranged from 0.59 to 8.11 ng/g lipid weight (lw). The levels of PBDEs in samples from Kampala capital city were significantly higher than those from Nakaseke (p < 0.01, Mann-Whitney U test). The most dominant congeners were BDE-209 and -47 (contributed 37.1% and 20.2%, respectively to ∑PBDEs), suggesting recent exposure of mothers to deca-and penta-BDE formulations. Fish and egg consumption, plastics/e-waste recycling and paint fumes were associated with higher levels of BDE-47, -153 and -99, respectively, implying that diet and occupation were possible sources of the pollutants. Estimated dietary intakes (ng kg^-1 body weight day^-1) for BDE-47, -99 and -153 were below the US EPA reference doses for neurodevelopmental toxicity, suggesting minimal health risks to nursing infants who feed on the milk. Generally, the risk quotients for BDE-47, -99 and -153 were <1 in majority (96%) samples, indicating that the breast milk of mothers in Uganda was fit for human consumption.

Dynamics of PCB exposure in the past 50 years and recent high concentrations in human breast milk: Analysis of influencing factors using a physiologically based pharmacokinetic model

In this study we reconstruct the long-term exposure of Czech mothers to polychlorinated biphenyls (PCBs) and determine the causes of high contamination of breast milk by indicator PCBs (iPCBs). A data set containing information from more than 1000 primiparous women from the Czech Republic was used, including iPCB concentrations in breast milk, individual physiology and living characteristics. The time series of PCB intakes for the whole period from the beginning of PCB production in 1958 until 2011 were reconstructed. We estimated the individual lifetime exposure of mothers for all iPCBs, i.e. congeners 28, 52, 101, 118, 138, 153 and 180, using a physiologically based pharmacokinetic (PBPK) model. Various model scenarios were investigated to determine the influence of physiology, age at delivery, past dietary exposure, and food composition on concentrations in breast milk for all iPCBs. The highest contributions to the presence of iPCBs in breast milk were observed for food composition. The main factor determining the concentration of higher-chlorinated PCBs (138, 153 and 180) was past exposure. The most important parameter for identification of children's postnatal exposure through breast milk was the time-span from the maximum of the exposure peak to the birth of the child. The current concentrations of iPCBs in breast milk in the Czech population are still high because the maximum of the exposure peak occurred more than 10 years later than in other European countries and was very broad, e.g. covered more than 10 years.

NIH workshop on human milk composition: summary and visions

Nationally representative data from mother-child dyads that capture human milk composition (HMC) and associated health outcomes are important for advancing the evidence to inform federal nutrition and related health programs, policies, and consumer information across the governments in the United States and Canada as well as in nongovernment sectors. In response to identified gaps in knowledge, the National Institute of Diabetes and Digestive and Kidney Diseases of the NIH sponsored the "Workshop on Human Milk Composition-Biological, Environmental, Nutritional, and Methodological Considerations" held 16-17 November 2017 in Bethesda, Maryland. Through presentations and discussions, the workshop aimed to 1) share knowledge on the scientific need for data on HMC; 2) explore the current understanding of factors affecting HMC; 3) identify methodological challenges in human milk (HM) collection, storage, and analysis; and 4) develop a vision for a research program to develop an HMC data repository and database. The 4 workshop sessions included 1) perspectives from both federal agencies and nonfederal academic experts, articulating scientific needs for data on HMC that could lead to new research findings and programmatic advances to support public health; 2) information about the factors that influence lactation and/or HMC; 3) considerations for data quality, including addressing sampling strategies and the complexities in standardizing collection, storage, and analyses of HM; and 4) insights on how existing research programs and databases can inform potential visions for HMC initiatives. The general consensus from the workshop is that the limited scope of HM research initiatives has led to a lack of robust estimates of the composition and volume of HM consumed and, consequently, missed opportunities to improve maternal and infant health.

Biomonitoring of bisphenols A, F, S in human milk and probabilistic risk assessment for breastfed infants

The present study addresses the presence of bisphenols A (BPA) and its analogs bisphenol F (BPF) and S (BPS) in milk of 120 mothers living in Valencia (Spain) and participating in the BETTERMILK project (year 2015). We also studied the factors that could influence the BPA levels and estimated the exposure and the risk for breast fed infants. The frequency of detection of total (conjugated + unconjugated) and unconjugated-BPA were 83% and 77%, with a geometric mean of 0.29 ng/mL and 0.15 ng/mL, respectively. The frequency of detection was much lower for total-BPF (22%) and total-BPS (1.1%). The place of residence of the mother and the use of personal care products showed significant association with BPA concentrations. The estimated daily intake of total-BPA for breastfed infants amounted to a geometric mean of 0.04 μg/kg bw and a 95th percentile of 1.0 μg/kg bw, below the tolerable daily intake of 4 μg/kg bw-day established by EFSA. To our knowledge, this is the largest biomonitoring study of bisphenols in human milk in Europe.

Concentrations of dioxins and furans in breast milk of women living near a hazardous waste incinerator in Catalonia, Spain

Since 1999, a hazardous waste incinerator (HWI) is operating in Constantí (Tarragona County, Catalonia, Spain). In 1996-1998, when the facility was being built, we started a monitoring program aimed at evaluating the impact of the emissions of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) by the HWI on the environment and the human health. This study aimed at determining the current concentrations of PCDD/Fs in breast milk samples of women living nearby the HWI and at comparing these levels and profiles with those obtained in the baseline (1996-1998) and previous surveys (2002, 2007 and 2012). Furthermore, the association between the dietary intake of PCDD/Fs and the congener profiles in breast milk was also explored. Twenty milk samples were collected from women living in Tarragona downtown and near the industrial area where the HWI is placed. The content of PCDD/Fs was analyzed by following a procedure derived from the US EPA methods 1613 and 8290A. The mean concentration of PCDD/Fs was 2.26 pg WHO-TEQ/g fat. No significant differences were found between women living in industrial and urban areas (1.67 pg vs. 2.48 pg WHO-TEQ/g fat). Interestingly, a notable significant reduction (81%) was observed with respect to the concentrations found in the baseline study. The profiles of PCDD/Fs in breast milk were similar independently on the area and period of collection, being mainly influenced by the intake of fish, meat, oils and fats. The decreasing trend of PCDD/Fs in human milk agrees with the reduction observed in the dietary intake of these pollutants. It was also concluded that the current levels of PCDD/Fs in human milk levels are not influenced by the HWI stack emissions.

Site-specific bioaccumulation of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/PCDFs) in mothers and their infants living in vicinity of Bien Hoa airbase, Southern Vietnam

Bien Hoa airbase is located in Dong Nai Province (Southern Vietnam). Several sites within the airbase are highly contaminated by Agent Orange/Dioxin, and thus, they are also commonly named as an Agent Orange/Dioxin hotpot. In the present study, 36 maternal milk samples were collected from primiparas who have lived at least 5 years in four wards, Buu Long, Quang Vinh, Trung Dung and Tan Phong, which are closed to Bien Hoa airbase in order to investigate the level and distribution of Agent Orange/Dioxin exposure in different local communities. The mean concentrations of PCDD/PCDFs in four investigated wards range from 6.4 to 13.6 pgTEQ/g lipid. The highest mean TEQ of PCDD/PCDFs was observed in Buu Long ward (13.6 pgTEQ/g lipid), followed by Tan Phong ward (12.3 pgTEQ/g lipid), and the lowest value was observed in Trung Dung ward (6.4 pgTEQ/g lipid). The mean concentration of 2,3,7,8-TCDD in Buu Long (7.6 pg/g lipid) was approximately 2-6 times higher than those in Tan Phong (3.9 pg/g lipid), Quang Vinh (2.3 pg/g lipid), or Trung Dung (1.2 pg/g lipid). These results imply site-specific exposure to PCDD/PCDFs in different local communities living around Bien Hoa airbase. The mean values of daily intake of dioxin estimated for the breast fed infants living in Buu Long, Quang Vinh, Trung Dung and Tan Phong were about 80, 37.5, 31.7 and 58 pg TEQ/kg bw/day, respectively.

Polychlorinated biphenyl concentrations in pooled serum from people in different age groups from five Chinese cities

Polychlorinated biphenyl (PCB) concentrations in human serum samples pooled by donor age and sex (≥60, 50-59, 40-49, 30-39, and 20-29 years old) were determined. The pooled samples were supplied by hospitals in five Chinese cities, which were Yitong (Jilin Province), Weifang (Shandong Province), Ganzi (Sichuan Province), Huaihua (Hunan Province), and Lingshui (Hainan Province). The total PCB concentrations were relatively low compared with concentrations that have been found in other parts of the world. Pentachlorobiphenyls were the dominant PCBs. The total PCB concentrations and the concentrations of most of the pentachlorobiphenyl congeners were slightly higher in the samples from younger donors than in the samples from older donors. The results indicated there is a new source of PCBs in China. Heptachlorobiphenyls in Lingshui may have been transported from Vietnam. Statistical analysis showed that young and old people had been exposed to different sources of PCBs. PCB 126 contributed more than the other dioxin-like PCBs to the total toxic equivalents when the samples were examined as a whole or by city, and the total toxic equivalents were higher in younger people than in older people for the whole sample set and for the Yitong samples.

Levels of PCDD/Fs, PBDEs, and PBDD/Fs in Breast Milk from Southern Taiwan

This study investigates the congener-specific concentrations of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs), polybrominated dibenzo-p-dioxins/furans (PBDD/Fs), and polybrominated diphenyl ethers (PBDEs) in 25 breast milk samples from southern Taiwan. Most investigated congeners in Taiwanese breast milk are detectable except for PBDD/Fs. The geometric means of PCDD/Fs and PBDEs in the breast milk are 2.44 pg WHO₂₀₀₅-TEQ/g lipid and 2810 pg/g lipid. Several PCDD/F and PBDE congeners were highly correlated to each other like 1,2,3,7,8-PeCDD and 2,3,4,7,8-PeCDF (r = 0.919, p < 0.001). The longest duration of menstruation could be predicted by BDE-153 (β = 0.252) and 1,2,3,4,6,7,8-HpCDF (β = 0.345) with adjustment of confounders using a multiple stepwise linear regression model (r = 0.963, p < 0.001).