Influence of maternal and sociodemographic characteristics on the accumulation of organohalogen compounds in Argentinian women. The EMASAR study

Exploring Prenatal Exposure to Halogenated Compounds and Its Relationship with Birth Outcomes Using Nontarget Analysis

Halogenated organic compounds (HOCs) are a class of contaminants showing high toxicity, low biodegradability, and high bioaccumulation potential, especially chlorinated and brominated HOCs (Cl/Br-HOCs). Knowledge gaps exist on whether novel Cl/Br-HOCs could penetrate the placental barrier and cause adverse birth outcomes. Herein, 326 cord blood samples were collected in a hospital in Jinan, Shandong Province from February 2017 to January 2022, and 44 Cl/Br-HOCs were identified with communicating confidence level above 4 based on a nontarget approach, covering veterinary drugs, pesticides, and their transformation products, pharmaceutical and personal care products, disinfection byproducts, and so on. To our knowledge, the presence of closantel, bromoxynil, 4-hydroxy-2,5,6-trichloroisophthalonitrile, 2,6-dibromo-4-nitrophenol, and related components in cord blood samples was reported for the first time. Both multiple linear regression (MLR) and Bayesian kernel machine regression (BKMR) models were applied to evaluate the relationships of newborn birth outcomes (birth weight, length, and ponderal index) with individual Cl/Br-HOC and Cl/Br-HOCs mixture exposure, respectively. A significantly negative association was observed between pentachlorophenol exposure and newborn birth length, but the significance vanished after the false discovery rate correction. The BKMR analysis showed that Cl/Br-HOCs mixture exposure was significantly associated with reduced newborn birth length, indicating higher risks of fetal growth restriction. Our findings offer an overview of Cl/Br-HOCs exposome during the early life stage and enhance the understanding of its exposure risks.

Hexachlorobenzene as a differential modulator of the conventional and metronomic chemotherapy response in triple negative breast cancer cells

Aim

Triple negative breast cancer (TNBC) is usually treated with high doses of paclitaxel, whose effectiveness may be modulated by the action of environmental contaminants such as hexachlorobenzene. High doses of paclitaxel cause adverse effects such as low cellular selectivity and the generation of resistance to treatment due to an increase in the expression of multidrug resistance proteins (MRPs). These effects can be reduced using a metronomic administration scheme with low doses. This study aimed to investigate whether hexachlorobenzene modulates the response of cells to conventional chemotherapy with paclitaxel or metronomic chemotherapy with paclitaxel plus carbachol, as well as to study the participation of the MRP ATP-binding cassette transporter G2 (ABCG2) in human TNBC MDA-MB231 cells.

Methods

Cells were treated with hexachlorobenzene alone or in combination with conventional or metronomic chemotherapies. The effects of treatments on cell viability were determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and the nuclear factor kappa B pathway participation was evaluated using a selective inhibitor. ABCG2 expression and its modulation were determined by western blot.

Results

Results confirmed that paclitaxel reduces MDA-MB231 cell viability in a concentration-dependent manner. Results also showed that both conventional and metronomic chemotherapies reduced cell viability with similar efficacy. Although hexachlorobenzene did not modify cell viability per se, it did reverse the effect induced by the conventional chemotherapy, without affecting the efficacy of the metronomic chemotherapy. Additionally, a differential modulation of ABCG2 expression was determined, mediated by the nuclear factor kappa B pathway, which was directly related to the modulation of cell sensitivity to another cycle of paclitaxel treatment.

Conclusions

The findings indicate that, in human TNBC MDA-MB231 cells, in the presence of hexachlorobenzene, the metronomic combination of paclitaxel plus carbachol is more effective in affecting the tumor biology than the conventional therapeutic administration scheme of paclitaxel.

Exploration of the correlation of serum polychlorinated biphenyl levels with luteal phase hormonal parameters and infertility in women with or without polycystic ovary syndrome

Introduction

Polychlorinated biphenyls (PCBs) are organic lipophilic pollutants that accumulate in the body. Previous research has linked PCBs with menstrual function; therefore, this study was undertaken to investigate the correlation of PCBs with luteal phase hormonal parameters of menstrual function at day 21 in a group of non-obese women prior to in vitro fertilization (IVF).

Methods

Fifty-eight non-obese Caucasian women from a UK academic center, 29 with polycystic ovary syndrome (PCOS) and 29 without, were recruited. PCOS women all had anovulatory infertility. Non-PCOS women: five with unexplained infertility, the remainder with male factor infertility (n=14) or tubal problems (n=10). Blood was withdrawn at day 21 of the menstrual cycle for non-PCOS women, at the time of mock embryo transfer. PCBs were measured using high resolution gas chromatography.

Results

Only PCB118, PCB153, PCB138 and PCB180 were detected in all samples, and levels did not differ between PCOS and non-PCOS subjects. In non-PCOS subjects, PCB153, PCB138 and PCB180 inversely correlated with estradiol (p<0.05); PCB118 and PCB138 inversely correlated with follicle stimulating hormone (FSH) (p<0.05); PCB118 (p<0.05), PCB153, PCB138 and PCB180 (all p<0.01) inversely correlated with luteinizing hormone (LH). Control women without PCOS with unexplained infertility showed higher levels of PCB118, PCB153, PCB138 and PCB180 (p<0.05) compared to those control women without PCOS with tubal or male factor infertility, though other hormonal parameters did not differ other than that FSH that was lower in the unexplained group (p=0.01). The only correlation observed in PCOS women with anovulatory infertility was that between PCB180 and progesterone (p<0.05).

Conclusion

PCBs correlated with luteal phase menstrual cycle hormones in control women without PCOS and may contribute to the mechanism of unexplained infertility; in PCOS women, no correlations of the PCBs were seen for estradiol, LH or FSH.

Breast cancer progression and kynurenine pathway enzymes are induced by hexachlorobenzene exposure in a Her2-positive model

Breast cancer is one of the leading cancers among women worldwide. Given the evidence that pesticides play an important role in breast cancer, interest has grown in pesticide impact on disease progression. Hexachlorobenzene (HCB), an aryl hydrocarbon receptor (AhR) ligand, promotes triple-negative breast cancer cell migration and invasion. Estrogen receptor β (ERβ) inhibits cancer motility, while G protein-coupled ER (GPER) modulates the neoplastic transformation. Tryptophan is metabolized through the kynurenine pathway by indoleamine-2,3-dioxygenase (IDO) and tryptophan-2,3-dioxygenase (TDO), with kynurenine signaling activation often predicting worse prognosis in cancer. In this context, we examined the HCB (0.005; 0.05; 0.5 and 5 μM) effect on LM3 cells, a human epidermal growth factor receptor 2 (HER2)-positive breast cancer model. Results show that HCB increases IDO and TDO mRNA levels and promotes cell viability, proliferation and migration through the AhR pathway. Moreover, HCB boosts mammosphere formation, vascular endothelial growth factor and cyclooxygenase-2 expression and reduces IL-10 levels. For some parameters, U-shaped or inverted U-shaped dose-response curves are shown. HCB alters ER levels, reducing ERβ while increasing GPER. These results demonstrate that exposure to environmentally relevant concentrations of HCB up-regulates the kynurenine pathway and dysregulates ERβ and GPER levels, collaborating in HER2-positive breast cancer progression.

Predictors of Maternal Serum Concentrations for Selected Persistent Organic Pollutants (POPs) in Pregnant Women and Associations with Birth Outcomes: A Cross-Sectional Study from Southern Malawi

Population exposure to persistent organic pollutants (POPs) may result in detrimental health effects, especially to pregnant women, developing foetuses and young children. We are reporting the findings of a cross-sectional study of 605 mothers in their late pregnancy, recruited between August 2020 and July 2021 in southern Malawi, and their offspring. The aim was to measure the concentrations of selected POPs in their maternal serum and indicate associations with social demographic characteristics and birth outcomes. A high level of education was the main predictor of p,p'-DDE (p = 0.008), p,p'-DDT (p < 0.001), cis-NC (p = 0.014), o,p'-DDT (p = 0.019) and o,p'-DDE (p = 0.019) concentrations in maternal serum. Multiparity was negatively associated with o,p'-DDE (p = 0.021) concentrations. Maternal age was also positively associated (p,p'-DDE (p = 0.013), o,p'-DDT (p = 0.017) and o,p'-DDE (p = 0.045) concentrations. Living in rural areas was inversely associated with high maternal serum concentrations of p,p'-DDT (p < 0.001). Gestational age was positively associated with p,p'-DDE (p = 0.031), p,p'-DDT (p = 0.010) and o,p'-DDT (p = 0.022) concentrations. Lastly, an inverse association was observed between head circumference and t-NC (p = 0.044), Oxychlordane (p = 0.01) and cis-NC (p = 0.048). These results highlight the need to continue monitoring levels of POPs among vulnerable populations in the southern hemisphere.

Serum Concentrations of Selected Poly- and Perfluoroalkyl Substances (PFASs) in Pregnant Women and Associations with Birth Outcomes. A Cross-Sectional Study from Southern Malawi

Pervasive exposure to per-and polyfluoroalkyl substances (PFASs) shows associations with adverse pregnancy outcomes. The aim of the present study was to examine the determinants of different serum PFAS concentrations in late pregnancy and their relationship with birth outcomes in southern Malawi. The sample included 605 pregnant women with a mean age of 24.8 years and their offspring from three districts in the southern region of Malawi. Six PFAS were measured in serum from third-trimester women. The serum PFAS concentrations were assessed with head circumference, birth length, birth weight, gestational age and ponderal index. Participants living in urban areas had significantly higher serum levels of PFOA, PFNA and SumPFOS, while SumPFHxS concentrations were higher in women from rural settings. High PFOA, PFNA and SumPFHxS concentrations were generally inversely associated with head circumference. Birth length was negatively associated with PFOA and PFNA while SumPFHxS was negatively associated with birth weight. SumPFOS was inversely associated with gestational age. Urban area of residence was the strongest predictor for high PFAS concentrations in the maternal serum and was generally associated with adverse birth outcomes. The results highlight the need to investigate SumPFHxS further as it follows a pattern that is different to similar compounds and cohorts.

Persistent Organic Pollutant Levels in Maternal and Cord Blood Plasma and Breast Milk: Results from the Rio Birth Cohort Pilot Study of Environmental Exposure and Childhood Development (PIPA Study)

Levels of polychlorinated biphenyls (PCB) and organochlorine pesticides (OCP) were evaluated in the breast milk and maternal and umbilical cord blood of pregnant women and their newborns in Rio de Janeiro, Brazil. The concentration of 11 PCB and 17 OCP were measured in 135 samples of maternal, and 116 samples of cord blood plasma, as well as 40, 47, and 45 samples of breast milk at 1st, 3rd, and 6th months after birth, respectively, using gas chromatography-mass spectrometry (GC-MS-MS). Women were asked to answer an enrollment questionnaire with reproductive, lifestyle, residential and sociodemographic questions. The most commonly detected OCPs and PCBs in the maternal and cord blood were 4,4'-DDE; β-HCH; ɣ-HCH; and PCB 28. 4,4'-DDE was also the most commonly detected OCP in breast milk samples. Although not statistically significant, ∑DDT levels were higher among women with pregestational BMI ≥ 30, and who were non-white and older (age > 40). Newborns with an Apgar score ≤ 8 at minute 5 of life showed significantly higher levels of ∑DDT in the cord blood. Persistent OCPs and PCBs were still detected in maternal and umbilical cord blood and breast milk, even after decades of their banishment in Brazil. They may pose a risk to maternal, fetal and children's health.

Pilot study on the concentrations of organochlorine compounds and potentially toxic elements in pregnant women and local food items from the Finnish Lapland

In the Arctic, main sources of persistent organic pollutants and potentially toxic elements are industry and agriculture in the lower latitudes. However, there are also local sources of pollution. Our study was focused on possible pollution in the Finnish Lapland, transferred from the Pechenganikel industrial complex located in the borders of Russia, Finland and Norway. Local food items and blood samples of pregnant women from the Inari municipality were collected and organochlorine compounds (OCs) and metal(oid)s analyzed. Most of the examined food samples showed detectable levels of these compounds. The mean concentrations of DDTs and polychlorobiphenyls (PCBs) were higher in fish (0.18-0.32 ng/g and 0.34-0.64 ng/g, respectively), than in the other food groups (0.027-0.047 ng/g and 0.11-0.20 ng/g, respectively). PCBs were found at the highest concentrations in blood samples of the pregnant women, and congeners 153 and 118 were dominant. The mean concentration of PCB153, 0.29 μg/kg serum lipid, was lower than those described in many other studies. Concerning DDTs, the 4,4'-DDT/4,4'-DDE ratio, 0.092, in the blood samples was lower than that observed in the food items, 0.25-0.71, reflecting old uses of the DDT pesticide. None of the observed levels of selected potentially toxic elements in blood samples and in food items exceeded the known safe limits. Higher concentrations of PCB52 and γ-HCH were observed in the serum of pregnant women who consumed greater amounts of meat, and berries and mushrooms, respectively. The OC concentrations from the pregnant women currently studied were lower than those observed fourteen years ago with pregnant women from the same municipality. Compounds whose occurrence is likely related to a long-distance transport showed clear decreases, e.g., 63% for PCBs, and for those from pesticides, decreases were 93% and 97% for 4,4'-DDE and β-HCH, respectively. No obvious influence from the Pechenganikel complex is observed from the results.

Seabird-mediated transport of organohalogen compounds to remote sites (North West Greenland polynya)

The role of sea birds as carriers of pollutants over long distances was evaluated by analyzing organochlorine and organobromine compounds in lake sediment cores from three remote sites around the North Water polynya (North West Greenland). One lake, NOW5, was in the vicinity of a little auk (Alle alle L.) bird colony, whereas the other two lakes, NOW14 and Q5, were undisturbed by seabirds. The former was strongly acidic (pH = 3.4) but the latter had a pH close to 8. Due to the guano loading, NOW5 exhibited higher chlorophyll concentrations (74 μg/L) than the other two lakes (1.6-3.4 μg/L), higher content of total phosphorous (0.34 mg/L vs. 0.007-0.01 mg/L) and total nitrogen (3.75 mg/L vs. 0.21-0.75 mg/L). The concentrations of all organohalogen compounds were substantially greater in NOW5 than in the other lakes, indicating the strong influence of these seabirds in the transport and deposition of these compounds to remote sites. However, not all compounds showed the same increases. Hexachlorocyclohexanes and endosulfans were more than 18 times higher in NOW5, the drin pesticides and hexachlorobenzene (HCB), between 9.5 and 18 times and DDTs, polybromodiphenyl ethers (PBDEs), polychlorobiphenyls (PCBs) and chlordanes about 2.7-6 times. These differences demonstrated that the bird-mediated deposition has preservation effects of the less stable and more volatile compounds, e.g. those with log Kaw < -2.4, log Koa < 9 and/or log Kow < 6.8. The sedimentary fluxes of PCBs, HCHs, drins, chlordanes, PBDEs, HCB and endosulfans were highest in the upper sediment layer of the polynya lake (year 2014). In contrast, the highest DDT fluxes were found in 1980. These trends indicate that despite restrictions and regulations, bird transport continues to introduce considerable amounts of organohalogen pollutants to the Arctic regions with the exception of DDTs, which show successful decline, even when mediated by bird metabolism.

Endocrine disruptor hexachlorobenzene induces cell migration and invasion, and enhances aromatase expression levels in human endometrial stromal cells

Endometriosis is the presence and growth of endometrial tissue outside of the uterus. Previous studies have suggested that endocrine disrupting chemicals such as organochlorine pesticides could be a risk factor for endometriosis. Hexachlorobenzene (HCB) is a weak ligand of the aryl hydrocarbon receptor (AhR) and promotes metalloproteinase and cyclooxygenase-2 (COX-2) expression, as well as, c-Src activation in human endometrial stromal cells (T-HESC) and in rat endometriosis model. Our aim was to evaluate the effect of HCB exposure on oestrogen receptor (ER) ɑ and β, progesterone receptor (PR) and aromatase expression, as well as, on cell migration and invasion in T-HESC and primary cultures of endometrial stromal cells from eutopic endometria of control subjects (ESC). Results show that HCB increases ERɑ and aromatase protein levels and reduces PR content in both T-HESC and ESC. However, the pesticide only increases ERβ expression in ESC, without changes in T-HESC. Moreover, cell migration and invasion are promoted by pesticide exposure involving the AhR, c-Src, COX-2 and ER pathways in T-HESC. HCB also triggers ERɑ activation via phosphorylation in Y537 through AhR/c-Src pathway. Our results provide experimental evidence that HCB induces alterations associated with endometriosis, suggesting that these mechanisms could contribute to pesticide exposure-induced endometriosis development.

Differential Bioaccumulation Patterns of α, β-Hexachlorobenzene and Dicofol in Adipose Tissue from the GraMo Cohort (Southern Spain)

To identify bioaccumulation patterns of α-, β- hexachlorocyclohexane (HCH) and dicofol in relation to sociodemographic, dietary, and lifestyle factors, adipose tissue samples of 387 subjects from GraMo cohort in Southern Spain were analyzed. Potential predictors of these organochlorine pesticides (OCP) levels were collected by face-to-face interviews and assessed by multivariable linear and logistic regression. OCPs were detected in 84.2% (β-HCH), 21.7% (α-HCH), and 19.6% (dicofol) of the population. β-HCH levels were positively related to age, body mass index (BMI), mother's occupation in agriculture during pregnancy, living in Poniente and Alpujarras, white fish, milk and water consumption, and negatively related to being male, living near to an agricultural area, working ≥10 years in agriculture, and beer consumption. Detectable α-HCH levels were positively related to age, BMI, milk consumption, mother's occupation in agriculture during pregnancy, and negatively with residence in Poniente and Alpujarras, Granada city, and Granada Metropolitan Area. Residence near to an agricultural area, smoking habit, white fish and water consumption, and living in Poniente and Alpujarras, Granada city and Granada Metropolitan Area were negatively associated with detectable dicofol levels. Our study revealed different bioaccumulation patterns of α, β-HCH and dicofol, probably due to their dissimilar period of use, and emphasize the need for assessing the exposure to frequently overlooked pollutants.

First nationwide exposure profile of major persistent organic pollutants among Korean adults and their determinants: Korean National Environmental Health Survey Cycle 3 (2015-2017)

Since 2009, Korea has measured the exposure levels of major environmental chemicals and heavy metals among representative adult populations through the Korean National Environmental Health Survey (KoNEHS). However, exposure to persistent organic pollutants (POPs) has never been assessed. This study reports the serum concentrations of twenty-four POPs and their influencing factors for Korean adults (n = 1295) who participated in the KoNEHS Cycle 3 (2015-2017). The POPs included seven organochlorine pesticides (OCPs), eleven polychlorinated biphenyls (PCBs), and six polybrominated diphenyl ethers (PBDEs). Among them, three OCPs (i.e., hexachlorobenzene (HCB), p,p'-dichlorodiphenyltrichloroethane (p,p'-DDT), and p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE)) and five PCBs (i.e., PCB52, PCB118, PCB138, PCB153, and PCB180) were detected in over 60% of the samples. PBDEs were not detected at a detection frequency of 60% or above. The most frequently detected POPs were p,p'-DDE (99.8%, geometric mean of 128.47 ng/g lipid), followed by PCB180 (98.8%, 8.49 ng/g lipid), PCB153 (98.8%, 13.14 ng/g lipid), HCB (96.2%, 67.08 ng/g lipid), PCB138 (95.2%, 8.84 ng/g lipid), PCB118 (89.6%, 2.66 ng/g lipid), p,p'-DDT (80.5%, 6.68 ng/g lipid), and PCB52 (71.2%, 1.57 ng/g lipid). The concentrations of most POPs were lower than or similar to concentrations reported in national-scale biomonitoring surveys. The only exception was HCB, whose concentration was up to seven-fold higher than the concentration reported by the Canadian Health Measures Survey. Excluding HCB and PCB52, most POPs showed increasing serum levels among older adults, adults with higher body mass index, adults living in coastal areas, and more frequent fish consumption. Relatively higher POP concentrations were observed in menopausal women. This study provides the first data on POP exposure levels among the representative adult population in Korea, and the results highlight the need to integrate POPs in the national biomonitoring program.

Serum Concentrations of Selected Organochlorines in Pregnant Women and Associations with Pregnancy Outcomes. A Cross-Sectional Study from Two Rural Settings in Cambodia

We conducted a cross-sectional study among 194 pregnant women from two low-income settings in Cambodia. The inclusion period lasted from October 2015 through December 2017. Maternal serum samples were analyzed for persistent organic pollutants (POPs). The aim was to study potential effects on birth outcomes. We found low levels of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCP), except for heptachlors, β-hexachlorocyclohexane (HCH), heptachlor epoxide, and p,p'-DDE. There were few differences between the two study locations. However, the women from the poorest areas had significantly higher concentrations of p,p'-DDE (p < 0.001) and hexachlorobenzene (HCB) (p = 0.002). The maternal factors associated with exposure were parity, age, residential area, and educational level. Despite low maternal levels of polychlorinated biphenyls, we found significant negative associations between the PCB congeners 99 (95% CI: -2.51 to -0.07), 138 (95% CI: -1.28 to -0.32), and 153 (95% CI: -1.06 to -0.05) and gestational age. Further, there were significant negative associations between gestational age, birth length, and maternal levels of o,p'-DDE. Moreover, o,p'-DDD had positive associations with birth weight, and both p,p'-DDD and o,p'-DDE were positively associated with the baby's ponderal index. The poorest population had higher exposure and less favorable outcomes.

AhR ligands reactivate LINE-1 retrotransposon in triple-negative breast cancer cells MDA-MB-231 and non-tumorigenic mammary epithelial cells NMuMG

Breast cancer is the most common cancer type in females worldwide. Environmental exposure to pesticides affecting hormonal homeostasis does not necessarily induce DNA mutations but may influence gene expression by disturbances in epigenetic regulation. Expression of long interspersed nuclear element-1 (LINE-1) has been associated with tumorigenesis in several cancers. In nearly all somatic cells, LINE-1 is silenced by DNA methylation in the 5́'UTR and reactivated during disease initiation and/or progression. Strong ligands of aryl hydrocarbon receptor (AhR) activate LINE-1 through the transforming growth factor-β1 (TGF-β1)/Smad pathway. Hexachlorobenzene (HCB) and chlorpyrifos (CPF), both weak AhR ligands, promote cell proliferation and migration in breast cancer cells, as well as tumor growth in rat models. In this context, our aim was to examine the effect of these pesticides on LINE-1 expression and ORF1p localization in the triple-negative breast cancer cell line MDA-MB-231 and the non-tumorigenic epithelial breast cell line NMuMG, and to evaluate the role of TGF-β1 and AhR pathways. Results show that 0.5 μM CPF and 0.005 μM HCB increased LINE-1 mRNA expression through Smad and AhR signaling in MDA-MB-231. In addition, the methylation of the first sites in 5́'UTR of LINE-1 was reduced by pesticide exposure, although the farther sites remained unaffected. Pesticides modulated ORF1p localization in MDA-MB-231: 0.005 μM HCB and 50 μM CPF increased nuclear translocation, while both induced cytoplasmic retention at 0.5 and 5 μM. Moreover, both stimulated double-strand breaks, enhancing H2AX phosphorylation, coincidentally with ORF1p nuclear localization. In NMuMG similar results were observed, since they heighten LINE-1 mRNA levels. CPF effect was through AhR and TGF-β1 signaling, whereas HCB action depends only of AhR. In addition, both pesticides increase ORF1p expression and nuclear localization. Our results provide experimental evidence that HCB and CPF exposure modify LINE-1 methylation levels and induce LINE-1 reactivation, suggesting that epigenetic mechanisms could contribute to pesticide-induced breast cancer progression.

Changes of organochlorine compound concentrations in maternal serum during pregnancy and comparison to serum cord blood composition

The concentrations of organochlorine compounds (OCs), including pentachlorobenzene, hexachlorobenzene (HCB), hexachlorocyclohexanes (α-, β-, γ- and δ-HCH), polychlorobiphenyls (PCBs 28, 52, 101, 118, 138, 153 and 180), DDT and metabolites, were measured in maternal serum samples collected at the first trimester of pregnancy, at delivery and in umbilical cord from a cohort of mother-newborn pairs from Tarragona (Spain) (n = 50), representing general population of a Mediterranean area from Southern Europe. The observed concentrations were generally low in comparison with previous studies in other world areas. Higher OC concentrations were observed in the maternal serum collected at delivery than in the first trimester and the cord blood concentrations were lower than the maternal levels. These results show for the first time a small but statistically significant increase in maternal venous concentration of OCs between the first trimester and delivery when measured in ng/ml. HCB, β-HCH and the PCB congeners in cord blood were significantly correlated with the concentrations of these compounds in maternal venous blood and the coefficients were stronger for the samples collected at delivery which was consistent with OC transfer from mother to foetus. In the case of DDT compounds, only 4,4'-DDT showed maternal-cord blood correlation which documented the low metabolic capacity of newborns for OC transformation, e.g. DDT into DDE. Maternal age was the most significant driver of the observed maternal venous OC concentrations in both periods, older ages involving higher concentrations. Higher body mass index was only significantly correlated with higher 4,4'-DDE concentrations in maternal venous blood and cord blood. In some cases, social class and education level were significantly correlated with OC concentrations, e.g. 4,4'-DDE in maternal venous blood from the first trimester and cord blood and PCB153 in maternal venous blood at delivery. In these cases, highest concentrations were found in the women with highest education level and most affluent social class. Comparison of the maternal OC concentrations of this cohort with those observed in 2002 in population of the same geographic area and age range shows decreases between two and ten times over this fourteen-year period.

Mother-child transfer rates of organohalogen compounds up to four years of age

BACKGROUND

Breastfed children absorb persistent and toxic chemicals such as organohalogen compounds (OHCs) during the entire lactation period. Nursing is a main contributor to the burden of these pollutants in the first years of life, hence further assessments on the OHC load processes are needed.

OBJECTIVES

To identify the determinants of OHC increase in children at four years of age, considering concentration gains, maternal venous concentrations and breastfeeding time.

METHODS

Concentrations of 19 organochlorine compounds (OCs) and 14 polybrominated diphenyl ethers (PBDEs) were analyzed in maternal venous (n = 466), cord blood (n = 326) and children venous serum at four years of age (n = 272) in the Asturias INMA cohort representing the Spanish general population. Data were evaluated considering the socio-demographic and individual information collected at recruitment and follow up surveys, as well as the OHC physical-chemical constants.

RESULTS

The four years-old children concentration gains of the most abundant OHCs showed strong correlations (R² = 0.65-0.93) with the maternal concentrations during pregnancy and lactation period. The child gain/maternal transfer rates of most correlated pollutants were similar.

DISCUSSION

Between 65 and 93% of the variance of OCs in four years-old children was explained by the maternal concentrations during pregnancy and the lactation period. The compounds with log(Kow) > 3.7 (hydrophobic) showed analogous child gain/maternal transfer rates indicating similar processes of membrane lipid dissolution and passive diffusion from the epithelial cells into the milk. Molecular weight of these pollutants did not influence on these rates. Compounds with low log(Koa) such as hexachlorobenzene are more volatile and less retained, involving lower child gain/maternal transfer rates. These results may be useful to anticipate the increase of the concentrations of OCs in children using the maternal concentration of these compounds during pregnancy and the planned lactation period and to implement prophylactic measures in mothers with high venous pollutant concentrations.

Impact of endocrine disruptor hexachlorobenzene on the mammary gland and breast cancer: The story thus far

Breast cancer incidence is increasing globally and exposure to endocrine disruptors has gained importance as a potential risk factor. Hexachlorobenzene (HCB) was once used as a fungicide and, despite being banned, considerable amounts are still released into the environment. HCB acts as an endocrine disruptor in thyroid, uterus and mammary gland and was classified as possibly carcinogenic to human. This review provides a thorough analysis of results obtained in the last 15 years of research and evaluates data from assays in mammary gland and breast cancer in diverse animal models. We discuss the effects of environmentally relevant HCB concentrations on the normal mammary gland and different stages of carcinogenesis, and attempt to elucidate its mechanisms of action at molecular level. HCB weakly binds to the aryl hydrocarbon receptor (AhR), activating both membrane (c-Src) and nuclear pathways. Through c-Src stimulation, AhR signaling interacts with other membrane receptors including estrogen receptor-α, insulin-like growth factor-1 receptor, epidermal growth factor receptor and transforming growth factor beta 1 receptors. In this way, several pathways involved in mammary morphogenesis and breast cancer development are modified, inducing tumor progression. HCB thus stimulates epithelial cell proliferation, preneoplastic lesions and alterations in mammary gland development as well as neoplastic cell migration and invasion, metastasis and angiogenesis in breast cancer. In conclusion, our findings support the hypothesis that the presence and bioaccumulation of HCB in high-fat tissues and during highly sensitive time windows such as pregnancy, childhood and adolescence make exposure a risk factor for breast tumor development.

Drivers of maternal accumulation of organohalogen pollutants in Arctic areas (Chukotka, Russia) and 4,4'-DDT effects on the newborns

BACKGROUND

One of the most worrying consequence of the production and use of persistent organohalogen pollutants (POPs) is the high accumulation in Arctic populations because of long-range transport. Study of the effects in these populations may illustrate human impacts that are difficult to assess in other locations with lower exposure to these compounds and more diverse pollutant influences.

OBJECTIVE

We aimed to identify the main maternal characteristics influencing on the accumulation of these compounds and the effects on the newborns in a highly exposed Arctic population (Chukotka, Russia).

METHODS

Organochlorine and organobromine compounds were analysed in maternal venous serum (n = 250). The study included data on residence, educational level, age, parity and body mass index (BMI) from self-reported questionnaires and measured anthropometric characteristics of newborns.

RESULTS

Concentrations of β-hexachlorocyclohexanes, hexachlorobenzene, 4,4'-DDT and polychlorobiphenyls were high when compared with those generally found in adult populations later than year 2000. The polybromodiphenyl ethers were negligible. These POP concentrations were higher than in Alaska and Arctic Norway and similar to those in Canada. The Chukotka mothers living in inland areas showed significant lower concentrations than those living in the coast (p < 0.001) except for 4,4'-DDT. The population from the Chukotsky District, a specific coastal area, showed the highest concentrations. Residence was therefore a main concentration determinant (p < 0.001) followed by maternal age, and in some cases parity and BMI (p < 0.05). 4,4'-DDT showed an association with the anthropometric characteristics of the newborns (p < 0.05). Mothers with higher 4,4'-DDT concentrations had longer gestational ages and gave birth to infants with higher weight and length.

CONCLUSIONS

The maternal accumulation patterns of POPs were mainly related with residence. Most of these compounds were found in higher concentration in women living at coastal areas except 4,4'-DDE and 4,4'-DDT which were of inland origin. This last pesticide was the pollutant showing positive associations with gestational age and newborn's weight and length. To the best of our knowledge, this is the first study reporting statistically significant associations between maternal 4,4'-DDT exposure and anthropometric characteristics of the newborns.

Exposure to environmental concentrations of hexachlorobenzene induces alterations associated with endometriosis progression in a rat model

Hexachlorobenzene (HCB) is a dioxin-like compound widely distributed and is a weak ligand of the aryl hydrocarbon receptor (AhR). Endometriosis is a disease characterized by growth of endometrial tissue in ectopic sites. Our aim was to investigate the impact of HCB on the endocrine, invasion and inflammatory parameters in a rat endometriosis model surgically induced. Female rats were exposed to HCB (1, 10 and 100 mg/kg b.w.) during 30 days. Results showed that HCB increases endometriotic like-lesions (L) volume in a dose-dependent manner. In L, HCB10 increases microvessel density (immunohistochemistry) and the vascular endothelial growth factor (VEGF), cyclooxygenase-2 (COX-2) and AhR levels (Western Blot), while HCB1 enhances aromatase expression (Western Blot). In addition, in eutopic endometrium (EU), HCB10/HCB100 augments microvessel density, VEGF and MMP-9 expression, while HCB1/HCB10 increases tumor necrosis factor-α (TNF-α) content in peritoneal fluid (ELISA). Interestingly, both L and EU from HCB-treated rats exhibited higher estrogen receptor α (ERα) (immunohistochemistry) and metalloproteases (MMP)-2 and -9 levels (Western Blot), as well as lower progesterone receptor (PR) expression (immunohistochemistry) than in control rats. Environmentally relevant concentrations of HCB could contribute to abnormal changes associated with endometriosis progression and development.

Drivers of the accumulation of mercury and organochlorine pollutants in Mediterranean lean fish and dietary significance

An integrated assessment of lean fish of commercial value as Hg and organochlorine compound source into the population of the Balearic Islands were reported. Dependences between pollutant concentrations, trophic level, fish species, specimen weight and physical-chemical properties were evaluated. Hg and total DDTs showed highest variability between fish species whereas PCBs and HCB displayed more constant median values. The organochlorine compounds found in highest concentrations were those with highest hydrophobicity, consistently with their higher bioaccumulation potential. These pollutant concentrations were higher in Mediterranean than Atlantic fish. Higher median total DDT and PCBs concentrations were also observed in the third than the second trophic level species. The observed concentrations were below the threshold recommended by the EU for human consumption (75ng/g wet weight). The Hg concentrations were higher in Mediterranean than Atlantic fish, with average values of 1.5μg/g ww and 0.43μg/g ww, respectively. Forty-one percent of the specimens from the Mediterranean and 25% of dusky grouper specimens from the Atlantic Ocean showed Hg concentrations above the EU recommended limits for human consumption, either 0.5μg/g ww or 1μg/g ww. In the third trophic level, a significant dependence between median Hg concentrations and weight of each studied species was observed, which remained significant in specimen weight correlations. Independent species correlations of Hg concentrations vs individual weight generally showed higher concentrations at higher weight. Weight/size of the individuals was therefore an important factor for Hg accumulation but the trend was modulated by a species effect. Extrapolation of the observed Hg concentrations in Mediterranean fish to Provisional Tolerable Weekly Intakes (PTWIs) showed higher intakes than the thresholds recommended by EFSA for adults and children, 110% and 140%, respectively. The estimated PTWIs for MeHg corresponded to 310% and 400% of the recommended threshold values. The PTWI values for organochlorine compounds were lower than those recommended.

Variations in serum concentrations of selected organochlorines among delivering women in Argentina. The EMASAR study

The EMASAR study is the first study to describe the body burden of OCs in Argentinian women after delivery. In total, 698 maternal serum samples from Salta (n = 498) and Ushuaia (n = 200) were collected in 2011-2012 and analyzed for a total of 7 polychlorinated biphenyls (PCBs) and 12 pesticide-related compounds. Only 11 of the compounds had detection rates above 60% in one or both places. Compared with Ushuaian women, those from Salta exhibited higher lipid-adjusted concentrations of p,p'-DDE, p,p'-DDT, β-HCH, and PCB 118 (p ≤ 0.003), with no differences in concentrations of PCB 153 and 138. After controlling for age, parity and heritage (born in the province or migrated there from other regions of Argentina), concentrations of p,p'-DDE, p,p'-DDT, β-HCH and all PCBs were significantly higher in Salta natives compared with Ushuaia natives or migrants (p ≤ 0.010). No variations between native and migrated Ushuaian women were observed other than for PCB 153 (6.1 versus 8.6 μg kg^-1 lipid, p = 0.022). Age was generally associated positively with the body burden of nearly all OCs and parity negatively so, with p,p'-DDD, o,p'-DDT, and o,p'-DDD residues and α-HCH in Ushuaia being the exceptions. The regional differences in OC concentrations are explained by contrasting domestic sources, historical and current uses, industrial emissions, dietary patterns and lifestyle factors, as well as long-range-transport. The relatively high PCB 118/PCB 180 ratio observed for both Argentinian communities likely reflects the use of technical mixtures with congener-specific composition. In a comprehensive comparison with other countries, the Argentinian OC concentrations were mostly in the lower range. It is concluded that a latitude effect equivalent to that operative in the Arctic region seems unlikely.

The Argentinian mother-and-child contaminant study: a cross-sectional study among delivering women in the cities of Ushuaia and Salta

Several ongoing international multidisciplinary projects have examined linkages between environmental chemicals and health. In contrast to Arctic regions, information for the Southern Hemisphere is scarce. Because of the inherent practice of pesticide utilisation and mismanagement, food security is potentially threatened. The most vulnerable period in human life occurs during pregnancy and early childhood, thus a focus on the body burdens of PTS in pregnant or delivering women is warranted. The current study was designed to investigate health risks related to exposure to PTS and food security in two regions of Argentina (Ushuaia and Salta). Our aims were to quantify concentrations of organic and inorganic toxins in serum or whole blood of delivering women and to collect pertinent dietary and medical information. The overall study design, the basic demographic features and essential clinical chemistry findings are described in the current paper. The socioeconomic differences between the two study areas were evident. On average, the women in Ushuaia were 4 years older than those in Salta (28.8 vs. 24.7 years). Respectively, the proportion of current smokers was 4.5 vs. 9.6%; and Salta had a higher birth rate, with 15.6% being para four or more. Saltanean women reported longer breastfeeding periods. Caesarean sections were more frequent in Ushuaia, with 43% of Caesarean deliveries compared with only 6% in Salta. Employment was high in both communities. Recognised environmental pollution sources in the vicinity of participant dwellings were widespread in Salta (56.1%) compared to Ushuaia (9%). The use of pesticides for insect control in homes was most common in Salta (80%). There is an urgent need for a comprehensive assessment of exposures in areas of the Southern Hemisphere. Our data set and the planned publications of observed concentrations of inorganic and organic environmental contaminants in both mothers and their newborns will contribute to this objective.