Level of polychlorinated dibenzo-p-dioxins, dibenzofurans and biphenyls (PCDD/Fs, PCBs) in human milk and the input to infant body burden

Dioxins in breast milk of Chinese mothers: A survey 40 years after the e-waste recycling activities

In the past two decades, numerous studies on dioxin concentrations in breast milk have been conducted in China. However, information concerning dioxin concentrations in breast milk from women living in e-waste recycling sites remains limited. Thus, this study aimed to evaluate health risk owing dioxin intake in e-waste recycling areas in China. In 2015, 42 mothers were recruited from an e-waste recycling site, and the same number of mothers were recruited from a reference site. We collected 10-mL breast milk samples from each participant. Breast milk concentrations of polychlorinated dibenzo-p-dioxins (PCDDs)/polychlorinated dibenzofurans (PCDFs) were significantly higher in the exposed group than in the reference group. The total toxic equivalents (TEQ) of PCDDs/DFs were 9.68 pg/g lipid in the exposed group, a value two times higher than those in the reference group (4.18 pg/g lipid). The estimated daily intake (EDI) of PCDD/DFs was calculated to assess the risk of dioxins through breastfeeding. The infant EDI level was two times higher in the exposed group (54.21 pg TEQ/kg body wt/day) than in the reference group (23.41 pg TEQ/kg body wt/day). Our findings suggest that mothers and their breastfeeding infants living in an e-waste recycling site were exposed to higher dioxin concentrations than those living in a reference site.

Musculoskeletal Disorder Symptoms among Workers at an Informal Electronic-Waste Recycling Site in Agbogbloshie, Ghana

Informal recycling of electrical and electronic waste (e-waste) has myriad environmental and occupational health consequences, though information about the chronic musculoskeletal health effects on workers is limited. The aim of this study was to examine the prevalence and intensity of self-reported musculoskeletal disorder (MSD) symptoms among e-waste workers at Agbogbloshie in Ghana-the largest informal e-waste dumpsite in West Africa-relative to workers not engaged in e-waste recycling. A standardized musculoskeletal discomfort questionnaire was administered to 176 e-waste workers (73 collectors, 82 dismantlers, and 21 burners) and 41 workers in a reference group. The number of body parts with musculoskeletal discomfort were 1.62 and 1.39 times higher for collectors and dismantlers than burners, respectively. A 1-week discomfort prevalence was highest for collectors (91.8%) followed by dismantlers (89%), burners (81%), and the reference group (70.7%). The discomfort prevalence for e-waste workers was highest in the lower back (65.9%), shoulders (37.5%), and knees (37.5%). Whole-body pain scores (mean ± SE) were higher for collectors (83.7 ± 10.6) than dismantlers (45.5 ± 7.6), burners (34.0 ± 9.1), and the reference group (26.4 ± 5.9). Differences in prevalence, location, and intensity of MSD symptoms by the e-waste job category suggest specific work-related morbidity. Symptom prevalence and intensity call attention to the high risk for MSDs and work disability among informal e-waste workers, particularly collectors and dismantlers.

Endocrine-Disrupting Organochlorine Pesticides in Human Breast Milk: Changes during Lactation

The aim of the present study was to assess infant safety associated with the occurrence of endocrine-disrupting organochlorine pesticides (OCP) in breast milk. Moreover, the association between pregnant mothers' dietary habits and these compounds levels in breast milk was investigated. Breast milk was collected at various stages of lactation. The samples were analyzed by the GC-MS method. The OCP concentrations ranged from < limit of detection (LOD) to 6.81 ng/g lipids. The highest OCP concentrations in breast milk occurred primarily within the first month of lactation, and decreased over the lactation period. It was found that the maternal consumption of certain food products-in particular pork, beef, poultry, eggs, and dairy products-could have affected the content of 1,1'-(2,2,2-Trichloroethane-1,1-diyl)bis(4-chlorobenzene), called DDT and its metabolites in the breast milk. The levels of beta-endosulfan were positively correlated with fish and poultry consumption. The redundancy analysis indicated that the diets of the pregnant women had an important impact on pesticide residues in the breast milk. There is a potential possibility of lowering the content of organochlorine compounds in breast milk by adhering to nutritional recommendations, e.g., avoiding the excessive consumption of fish and other raw food materials of unknown origin.

The relationship between perinatal exposure to dioxins and serum steroid hormone levels in preschool-aged children at an e-waste region in China

Perinatal exposure to dioxins affects steroid hormone synthesis. The purpose of the present study was to evaluate the associations between perinatal exposure to dioxins and serum steroid hormone levels in preschool-aged children from an e-waste recycling region in China. In the present study, we enrolled 50 pairs of mothers and infants from the Taizhou, Luqiao region in 2015. Of the 50 pairs of mothers and infants, 42 pairs participated in this study when the children were 4 years old. We measured breast milk dioxin concentrations using high-resolution gas chromatography/mass spectrometry. Additionally, we used liquid chromatography-tandem mass spectrometry to measure the concentrations of progesterone, testosterone, androstenedione (A-dione), and dehydroepiandrosterone (DHEA) in serum samples from the 4-year-old children. We used multivariate linear regressions to assess the associations between dioxin congeners and steroid hormones. Results were reported as beta estimates and 95% confidence intervals by bootstrapping. We observed sex-related differences between breast milk dioxins and serum steroid hormone levels in 4-year-old children. An increase in breast milk dioxins was associated with a decrease in testosterone in serum samples from boys. Similarly, an increase in breast milk dioxins was associated with a decrease in progesterone levels in serum samples from girls. However, dioxins were not associated with changes in the levels of testosterone, DHEA, or A-dione in girls. Based on these results, we conclude that perinatal exposure to dioxins modifies steroidogenesis in preschool-aged children. However, the long-term impact of dioxins requires further large-scale studies to assess these effects in school-going children and adolescents.

Effects of perinatal dioxin exposure on development of children: a 3-year follow-up study of China cohort

The purpose of this study was to investigate the longitudinal effects of perinatal exposure to dioxin on physical growth in a 3-year follow-up study. In 2015, 27 mother-infant pairs living in an electronic waste (e-waste) dismantling region and 35 pairs living in a control region were enrolled in the present study. Breast milk samples were collected at 4 weeks after birth. Physical growth, including weight, height, and head and chest circumferences, was measured at 6 months and 3 years of age. Dioxin levels in the breast milk were measured by gas chromatography/high-resolution mass spectrometry. Levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin and toxic equivalency values in maternal breast milk of polychlorinated dibenzodioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and PCDDs/PCDFs were significantly higher in women residing in the e-waste dismantling region. In 3-year-old boys, inverse associations were found between height and PCDDs-TEQ. In girls, positive associations were found between height and 2,3,7,8-TetraCDD, PCDDs-TEQ, and PCDDs/PCDFs-TEQ, and for weight and PCDDs-TEQ and PCDDs/PCDFs-TEQ at 3 years of age. In this study, sex-specific differences were observed in children, in whom dioxin exposure decreased growth in boys but increased growth in girls during the first 3 years of life.

Polycyclic aromatic hydrocarbons in breast milk of obese vs normal women: Infant exposure and risk assessment

Biomonitoring of human breast milk is one of the best ways to identify body burdens of contaminants and associated risk estimation. The objectives of the current study were to evaluate milk concentrations of persistent organic pollutants (POPs), mainly polycyclic aromatic hydrocarbons (PAHs), associated exposure estimation, and the role of body mass index (BMI) in their bioaccumulation. A total of 45 breast milk samples were collected from 24 women with BMI > 30 (obese) and 21 women with BMI < 25 (18.5-24.9, normal) from 14 different counties surrounding Lubbock in west Texas/New Mexico (age range: 18-34 years). Samples were analyzed using high resolution gas chromatography coupled with mass spectrometry. A total of 31/45 (69%) of samples tested positive for PAHs. Phenanthrene was the most frequently detected PAH followed by pyrene and fluoranthene. The mean of individual PAH concentration for all samples ranged from 0 to 25.1 ng/g milk fat; the sum of all means of individual PAHs was 146.9 ng/g milk fat. The mean concentration of total PAHs in the BMI > 30 group was 224.8 ng/g milk fat, which was approximately 4 times the mean concentration of total PAHs in the BMI 18.5-24.9 group (57.9 ng/g milk fat). None of the samples from the BMI 18.5-24.9 group contained higher molecular weight (5-6 rings) PAHs, while in the BMI >30 group, a total of 11 PAHs including listed EPA priority pollutants were observed. In this study, benzo(b)fluoranthene was found to contribute the highest percentage of carcinogenic PAHs (32.08%), yet it was not detected in any samples from the BMI 18.5-24.9 group. The estimated total PAHs intakes by infants via obese and normal mothers' milk were 1.26 and 0.32 (μg/kg/day), which are 0.049 and 0.003 (μg/kg/day) B[a]P equivalent, respectively. These findings suggest that breastfed babies from obese mothers are potentially at higher risk of exposure to carcinogenic PAHs.

Patterns of PCB exposure among Akwesasne adolescents: The role of dietary and inhalation pathways

AIM

The objective of this study is to determine if consumption of fish and other dietary elements are related to the serum PCB levels of a group of adolescents. A dietary pattern approach is used to provide a more complete dietary exposure profile rather than a single food/group approach. Additionally, dietary patterns are examined in relation to traditional PCB groupings as well as derived PCB congener profiles.

PARTICIPANTS/SETTING AND METHODS

The sample is comprised of 246 Mohawk adolescents between the ages of 10-16.9 years of age residing at the Akwesasne Mohawk Nation. Food frequency data was collected and serum PCB levels were (101 congeners) quantitated during a cross-sectional study investigating adolescent exposure to environmental pollutants.

RESULTS

Principal component analysis identified four dietary patterns: "well-rounded" "snacks and sweets" "fruits and vegetables" "fish and dairy" and four PCB congener profiles: "1248-like", Persistent/"1260-like", "mono-ortho", and "1254-like". In a multiple regression models, the "fish and dairy" dietary or traditional PCB determinants (age, sex, prior breastfeeding, BMI, pattern) were each predictors of one or more of three of the identified PCB congener profiles. However, the "1248-like" pattern was not related to either dietary pattern or any of the typical PCB determinants, suggesting an alternative source/exposure pathway for this congener profile.

CONCLUSION

Even relatively low levels of fish consumption within the composite dietary matrix of adolescents at Akwesasne remains a pathway of exposure to postnatally acquired PCBs. In addition, there is evidence of an unidentified, perhaps airborne, exposure pathway that warrants further attention as this congener profile accounted for 50% of the total variance within the adolescents' serum PCB levels.

Relationship between e-waste recycling and human health risk in India: a critical review

Informal recycling of waste (including e-waste) is an emerging source of environmental pollution in India. Polychlorinated biphenyls (PCBs), polychlorinated diphenyl ethers (PBDEs), and heavy metals, among other substances, are a major health concern for workers engaged in waste disposal and processing, and for residents living near these facilities, and are also a detriment to the natural environment. The main objective of this review article was to evaluate the status of these impacts. The review found that, huge quantity of e-waste/waste generated, only a small amount is treated formally; the remainder is processed through the informal sector. We also evaluated the exposure pathways, both direct and indirect, and the human body load markers (e.g., serum, blood, breast milk, urine, and hair), and assessed the evidence for the association between these markers and e-waste exposure. Our results indicated that the open dumping and informal e-waste recycling systems should be replaced by the best available technology and environmental practices, with proper monitoring and regular awareness programs for workers and residents. Further and more detailed investigation in this area is also recommended.

Persistent Organic Pollutants and Concern Over the Link with Insulin Resistance Related Metabolic Diseases

Persistent organic pollutants (POPs) are mostly halogenated compounds tending to persist in the environment, enter into the food chain, and accumulate in fat mass of mammals due to their high lipophilicity. They include some organochlorine pesticides, polychlorinated biphenyls, brominated flame retardants and polycyclic aromatic hydrocarbons. Some of these chemicals were widely used in the past so that their residues can be detected in the human body, though their usage has been banned for years. POPs have been shown to perturb the health of biological systems in different ways evidenced by carcinogenicity and disrupting effects on endocrine, immune, and reproductive systems. There are many epidemiologic and experimental studies on the association of exposure to POPs with insulin resistance and related metabolic disorders like obesity, diabetes, and metabolic syndrome. Inflammation as a known mechanism accompanying insulin resistance has also been shown to arise in insulin target tissues exposed to POPs. This review addresses the breast milk concentration of POPs in different regions of the world, synthesizes the current information on the association of POPs with insulin resistance related metabolic disorders, and discusses the inflammation as an involved mechanism. Considering high prevalence of insulin resistance related metabolic diseases and their relation with POPs, much need is felt regarding international and regional programs to not only limit their production and usage but eliminate these persistent pollutants from the environment.

Duration of breastfeeding and serum PCB 153 concentrations in children

Polychlorinated biphenyls (PCBs) are toxic, persistent, and bioaccumulative chemicals which, because of their lipophilic properties, are abundant in human breast milk. Breastfed infants are therefore at risk of being exposed to considerable amounts of PCBs. The commonly used exposure estimations, based solely on breast milk PCB levels and duration of breastfeeding, may lead to exposure misclassification. To improve assessments of exposure to PCBs, we determined PCB 153 serum concentration, as a model substance for PCBs, at the critical time of weaning for each child in 305 breastfed infants from 5 single time point concentration measurements spread over 7 years and data on duration of breastfeeding, using an earlier developed model of the system type. We approximated the dependence of PCB 153 serum concentration, Ctbf, adjusted to cord serum concentration, C0, on nursing period, by a polynomial function Ctbf/C0=0.596+0.278t-0.0047t(2) which reliably predicts exposure to PCB 153 of breastfed infants, important for assessment of dose-outcome relationships. Adjustment of current serum concentrations to cord serum concentration improved validity of exposure assessment.

Determination of PCDD/Fs in breast milk of women living in the vicinities of Da Nang Agent Orange hot spot (Vietnam) and estimation of the infant's daily intake

Seventeen toxic congeners of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were determined in breast milks using the high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS) method. Twenty seven breast milk samples were collected from primiparae who have lived over 5 years in wards namely Chinh Gian, An Khe, Khue Trung, and Hoa Thuan Tay which are located near the Da Nang Agent Orange hot spot (the AO/Dioxin hot spot). The samples were then analyzed for PCDD/F residues in order to assess the human exposure to dioxins from the AO/Dioxin hot spot, especially health risk to the breast-fed infants. The average TEQ levels in the four studied cohorts ranged from 8.1 to 26 pg/g lipid, with the highest level up to 51 pg TEQ/g lipid found in the An Khe ward. The TEQ level was correlated with geographical position and ranking in the order of Khue Trung, Hoa Thuan Tay, Chinh Gian and An Khe. The mean estimated PCDD/Fs infant's daily intake in the cohort of Khue Trung, Hoa Thuan Tay, Chinh Gian and An Khe was about 41, 122, 124, and 134 pg TEQ/kg bw/day, respectively, which are much higher than the tolerable daily intake proposed by the World Health Organization (4 pg TEQ/kg bw/day).

A review of environmental fate, body burdens, and human health risk assessment of PCDD/Fs at two typical electronic waste recycling sites in China

This paper reviews the levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in different environmental media, human body burdens and health risk assessment results at e-waste recycling sites in China. To provide an indication of the seriousness of the pollution levels in the e-waste recycling sites in China, the data are compared with guidelines and available existing data for other areas. The comparison clearly shows that PCDD/Fs derived from the recycling processes lead to serious pollution in different environmental compartments (such as air, soil, sediment, dust and biota) and heavy body burdens. Of all kinds of e-waste recycling operations, open burning of e-waste and acid leaching activities are identified as the major sources of PCDD/Fs. Deriving from the published data, the estimated total exposure doses via dietary intake, inhalation, soil/dust ingestion and dermal contact are calculated for adults, children and breast-fed infants living in two major e-waste processing locations in China. The values ranged from 5.59 to 105.16 pg WHO-TEQ/kg bw/day, exceeding the tolerable daily intakes recommended by the WHO (1-4 pg WHO-TEQ/kg bw/day). Dietary intake is the most important exposure route for infants, children and adults living in these sites, contributing 60-99% of the total intakes. Inhalation is the second major exposure route, accounted for 12-30% of the total exposure doses of children and adults. In order to protect the environment and human health, there is an urgent need to control and monitor the informal e-waste recycling operations. Knowledge gaps, such as comprehensive dietary exposure data, epidemiological and clinical studies, body burdens of infants and children, and kinetics about PCDD/Fs partitions among different human tissues should be addressed.

Infant dietary exposure to dioxins and dioxin-like compounds in Greece

The dietary exposure of infants to polychlorinated dibenzo dioxins and furans (PCDD/Fs) and dioxin like polychlorinated biphenyls (dl-PCBs) is an issue of great social impact. We investigated for the first time the dietary intake of these compounds in infants living in Greece. We included in our study two age groups: 0-6 months, when infants are fed exclusively by human milk and/or formula milk, and 6 to 12 months, when solid food is introduced to nutrition. We took into consideration analytical results for PCDD/Fs and dl-PCBs concentrations in the most popular infant formulae in the Greek market, previous data for mother milk concentrations of PCDD/Fs and dl-PCBs from Greece, and finally analytical data for fat-containing food products from the Greek market. In the first study group, it was found than in infants exclusively fed by breast milk, the calculated sum of PCDD/Fs and dioxin-like PCBs (60.3-80.4 TEQ pg/kg body weight) was significantly higher than that of infants that consume a combination of human milk and formula (31.2-41.6 TEQ pg/kg body weight). In the second study group, separate daily intake estimations were performed for babies receiving human milk (estimated total daily intake 19.76-24.95 TEQ pg/kg body weight) and formula milk (estimated total daily intake 1.60-2.24 TEQ pg/kg body weight). The risks of this exposure should not be overestimated because nursing is restricted to a limited period of human life and besides, the potential consumption of higher levels of dioxin-like compounds is fully compensated by the significant benefits of breast-feeding.

Individual breast milk consumption and exposure to PCBs and PCDD/Fs in Hungarian infants: a time-course analysis of the first three months of lactation

Polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are persistent, bioaccumulative and toxic chemicals. These compounds are transferred to breast milk, therefore breastfed infants are at risk of being exposed to considerable amounts of PCBs and PCDD/Fs during this sensitive age. In the present study individual breast milk samples were collected at three time points (days 5, 12 and 84 postpartum) from 22 mothers who delivered their infants during 2007 in Baranya County, Hungary. Breast milk samples were analyzed for 17 PCDD/Fs, 12 dioxin-like (DL) PCBs and 7 non-dioxin-like (NDL) PCBs using high-resolution gas chromatography/high-resolution mass spectrometry. Each infant's daily breast milk consumptions have been measured biweekly over three months. The concentration of several PCB and PCDD congeners in breast milk decreased significantly during lactation, with a main decline between days 5 and 12. The total toxic equivalent (TEQ) concentrations, derived from PCDD/Fs and DL-PCBs, were 3.17±1.72, 2.70±1.57 and 2.41±1.47 pg TEQ/g fat at the three time points, respectively. The corresponding NDL-PCB concentrations were 33.5±29.2, 27.4±20.6 and 26.9±24.8 ng/g fat, respectively. The results highlight the importance of timing of breast milk sampling for consistent exposure assessment estimation. Levels of pollutants in Hungarian breast milk samples were at the lower concentration range when data from Europe are considered. This is the first study in Hungary where each infant's daily intakes of PCBs and PCDD/Fs via breast milk have been measured. The daily intakes of PCDD/Fs and DL-PCBs via breastfeeding per kg body weight were 11.79±6.42, 16.54±13.02 and 11.59±7.70 pg TEQ/kg bw on days 5, 12 and 84, respectively. The exposure was the highest on day 12 but at all three time points each infants' daily exposure to PCDD/Fs and DL-PCBs via breastfeeding exceeded the tolerable daily intake (TDI) of 2 pg TEQ/kg bw per day. These levels are still lower than corresponding levels recently measured in many European countries. Whether the milk-derived POP exposure levels of infants reported here constitute any health risk that may manifest later in life awaits further scrutiny.

Determination of chlorinated pesticides, polychlorinated biphenyls, and polybrominated diphenyl ethers in human milk from Bizerte (Tunisia) in 2010

Thirty persistent organohalogen compounds including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) were determined in breast milk samples (n=36) of primipara and multipara mothers from Bizerte in 2010. The analytical procedure involved the application of liquid-liquid extraction and gas chromatography with electron capture detector (GC-ECD) or mass spectrometry detector (GC-MS) for identification and quantification. Organohalogen compounds were found in all the analyzed samples, with predominance of p,p'-DDE, p,p'-DDT, p,p'-DDD, HCB and PCBs. The mean concentration of ∑DDTs in breast milk was 1163.9 ng g(-1) lipid wt. The ratio of p,p'-DDE/p,p'-DDT was low, suggesting that there is fresh intake of commercial DDT products in Bizerte. The mean levels of HCB and PCB were 286.8 and 331.2 ng g(-1) lipid wt respectively. These results were compared with the levels obtained in a previous study carried out in the same area in 2003. A general decrease of ∑DDTs levels and an increase of PCB levels were observed. Among the 10 PBDE congeners evaluated, BDE-28, BDE-47, BDE-99, BDE-66, BDE-138, BDE-100, BDE-154, BDE-153, and BDE-183 were detected in the analyzed samples at different frequency. The total PBDE concentrations ranged from 2.5 to 22.6 ng g(-1) lipid wt in the samples, with a mean and median value of 10.7 and 9.8 ng g(-1) lipid wt respectively. To our knowledge, this is the first data of PBDEs in Tunisian human milk. The present study shows that age and parity are factors influencing the levels of some organohalogen compounds in human milk.

The effect of in utero exposure to dioxins and polychlorinated biphenyls on reproductive development in eight year-old children

We have previously reported on the effects of in utero exposure to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) on thyroid function and growth hormone concentrations at birth and in two and five year-old children. Herein, we present our most recent follow-up examination findings for the same cohort of children at eight-years of age. A total of 56 children (23 boys, 33 girls) were examined. Bone age (BA), hormone concentrations, and indicators of reproductive development including Tanner, breast, genital, and armpit stages were assessed. Estradiol concentrations were significantly lower in children exposed to higher levels than median of PCDD/Fs+PCBs TEQ compared to the children exposed to levels lesser than median (P=0.003). Girls exposed to higher levels than median of indicator PCBs had a significantly greater proportion in genital stage 1 and shorter fundi and uteri lengths, as compared to those exposed to low levels (P=0.025 and P<0.05, respectively). There was a significant negative relationship between estradiol concentrations and PCDD/Fs+PCB exposure level (P=0.005). After adjusting for BA, there was a significant association between fundus length and indicator PCB exposure level (P=0.034). Exposure to both high levels of ΣPCDD/Fs+PCBs TEQ and high levels of total PCBs was associated with decreased fundus length (P=0.016) and uterus length (P=0.016). In utero exposure to high levels of PCDD/Fs and PCBs may result in lower estradiol concentrations in eight year-old children and impaired reproductive development in girls.

PCB153 reduces telomerase activity and telomere length in immortalized human skin keratinocytes (HaCaT) but not in human foreskin keratinocytes (NFK)

Polychlorinated biphenyls (PCBs), ubiquitous environmental pollutants, are characterized by long term-persistence in the environment, bioaccumulation, and biomagnification in the food chain. Exposure to PCBs may cause various diseases, affecting many cellular processes. Deregulation of the telomerase and the telomere complex leads to several biological disorders. We investigated the hypothesis that PCB153 modulates telomerase activity, telomeres and reactive oxygen species resulting in the deregulation of cell growth. Exponentially growing immortal human skin keratinocytes (HaCaT) and normal human foreskin keratinocytes (NFK) were incubated with PCB153 for 48 and 24days, respectively, and telomerase activity, telomere length, superoxide level, cell growth, and cell cycle distribution were determined. In HaCaT cells exposure to PCB153 significantly reduced telomerase activity, telomere length, cell growth and increased intracellular superoxide levels from day 6 to day 48, suggesting that superoxide may be one of the factors regulating telomerase activity, telomere length and cell growth compared to untreated control cells. Results with NFK cells showed no shortening of telomere length but reduced cell growth and increased superoxide levels in PCB153-treated cells compared to untreated controls. As expected, basal levels of telomerase activity were almost undetectable, which made a quantitative comparison of treated and control groups impossible. The significant down regulation of telomerase activity and reduction of telomere length by PCB153 in HaCaT cells suggest that any cell type with significant telomerase activity, like stem cells, may be at risk of premature telomere shortening with potential adverse health effects for the affected organism.

Cord blood levels of thyroid hormones and IGF-1 weakly correlate with breast milk levels of PBDEs in Taiwan

In vivo studies indicate that prenatal or neonatal exposure of rodents to polybrominated diphenyl ethers (PBDEs) disrupts thyroid hormone balance, but few studies have reported an association of PBDEs and insulin-like growth factor 1 (IGF-1). The goal was to examine whether PBDEs exposure affects the levels of thyroid hormones and IGF-1 in cord blood. Study participants were healthy pregnant women recruited from the general population in central Taiwan between 2000 and 2001 and in southern Taiwan from 2007 to 2009. One-hundred-forty-nine breast milk samples (n=149), which were collected within one month after delivery, were analyzed using a high resolution gas chromatograph equipped with a high resolution mass spectrometer. The average and median levels of breast milk Σ(14)PBDEs were 5.34 and 3.38 ng/g lipid in 2000-2001 and 5.22 and 3.13 ng/g lipid in 2007-2009, respectively. In general, levels of PBDE congeners were very low in this study population and not significantly different between the years 2000-2001 and 2007-2009. Breast milk Σ(14)PBDEs were not significantly correlated with thyroid hormones and IGF-1 in cord blood. After examining multiple stepwise linear regression models with adjustment for maternal age, pre-pregnancy body mass index (BMI), parity, gestational age, and region (namely, central and southern Taiwan), we found that log of T4 in cord blood was significantly but slightly correlated with higher BDE-154 (B=0.113, p=0.017) in breast milk. The log of FT4 concentration was significantly related to a decrease in the log of BDE-99 level (B=-0.137, p=0.043) and an increase in the log of BDE-154 level (B=0.158, p=0.008). Meanwhile, the log of IGF-1 level was also significantly linked to an increase in the log of BDE-196 level (B=0.532, p=0.028) and decrease in the log of BDE-85 level (B=-0.235, p=0.018). Few epidemiological studies report an association between PBDEs exposure and IGF-1. Based on our findings, further in vivo and epidemiological studies are encouraged and needed to explore associations between PBDEs exposure and levels of thyroid hormones and IGF-1.

Placental docosahexaenoic and arachidonic acids correlate weakly with placental polychlorinated dibenzofurans (PCDF) and are uncorrelated with polychlorinated dibenzo-p-dioxins (PCDD) or polychlorinated biphenyls (PCB) at delivery: a pilot study

Long chain polyunsaturated fatty acids (LC-PUFA), ARA (arachidonic acid, 20:4n-6) and DHA (docosahexaenoic acid, 22:6n-3) have positive effects and environment pollutants, polychlorinated dibenzo-p-dioxins/dibenzofurans(PCDD/F) and polychlorinated biphenyls (PCB) have negative effects on neural development during early life. Placental dioxin/PCB serves as markers for cumulative exposure to fetus. Fatty acid composition of placenta depends on nutrient supply during pregnancy, serving as indicators for fetal ARA and DHA accretion. This study investigated correlation between placental PCDD/F and PCB toxic equivalent (TEQ) and LC-PUFA in 34 pregnant women from Taiwan. Placental PCDF TEQ were inversely correlated with placental ARA (p=0.020), C20:3n-6 (p=0.01), C22:4n-6 (p=0.04), C22:5n-6 (p<0.01) and with DHA (p=0.03), but ARA and DHA did not vary with PCDD, dioxin-like and indicator PCB. After adjustment for age and body mass index, a one-unit PCDF TEQ increase was associated with 1.021%w/w and 0.312%w/w decreases in ARA (β=-1.021, p=0.03) and DHA (β=-0.312, p=0.03). Since ARA and DHA were unrelated to three classes of toxins, and a weak negative association was found with PCDF, these data provide no basis for discouraging marine fish consumption during pregnancy for Taiwan women on the basis of these organics. Pregnant women should consume fish for its unique package of nutrients while avoiding few species with high organic pollutant or mercury contamination.

PCDD, PCDF, PCB and PBDE concentrations in breast milk of mothers residing in selected areas of Slovakia

The concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin-like polychlorinated biphenyls (dl-PCBs) and polybrominated diphenylethers (PBDEs) in 33 breast milk samples collected in 2006-2007 from primipara mothers close to four industrial areas of Slovak Republic were determined. The total PCDDs/PCDFs and dl-PCBs expressed as TEQ based on WHO TEFs 1998 in breast milk samples varied from 5.0 to 51.8 pg g(-1) fat (median: 13.1 pg g(-1) fat; mean: 18.0 pg g(-1) fat). The measurements of seven PBDE congeners (IUPAC No. 28, 47, 99, 100, 153, 154, and 183) were performed for the first time in human milk from Slovakia. PBDE levels ranged between 0.22 and 1.62 ng g(-1) fat, with median and mean value of 0.43 ng g(-1) fat and 0.57 ng g(-1) fat respectively. No statistically significant differences were observed between studied areas in total PBDE concentrations. Furthermore, this study presents first results concerning the daily intake (DI) of PCDDs/PCDFs and dioxin-like compounds for the most vulnerable breast-fed infant population in Slovakia. The total PCDD/PCDF and dl-PCB DI for an infant during the first 2 months of life was estimated in a range from 14.4 to 230 pg TEQ kg(-1)b.w., with a median value of 58.9 pg TEQ kg(-1)b.w.. The DI values substantially exceeded the tolerable daily intake (TDI) 1-4 pg TEQ kg(-1)b.w. recommended by WHO. The dietary infant intake concerning PBDEs was estimated to be between 0.69 and 7.1 ng kg(-1)b.w.d(-1), with median value of 1.7 ng kg(-1)b.w.d(-1).

PCDD/Fs and dioxin-like PCBs in human milk and estimation of infants' daily intake: a review

This paper reviews the recent scientific literature on PCDDs, PCDFs and dioxin-like PCBs in human milk. All the papers reporting levels of these contaminants in human breast milk published from January 2000 to January 2009 and available on the www.sciencedirect.com web site were identified and included. The aim was (1) to study levels of PCDDs, PCDFs and PCBs in human milk in mothers from different geographical areas and assess infant exposure to these contaminants; (2) to study the effect of variables such as the mother's age, number of deliveries, dietary and smoking habits and her own nutrition in infancy, and the environment, on levels of the contaminants in breast milk; (3) to study time patterns, and (4) to identify data gaps.

The effect of waste combustion on the occurrence of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) in breast milk in Italy

Levels of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were measured in the breast milk of mothers living in Giugliano (Campania, Italy), an area at increased risk of PCDD and PCDF exposure caused by recent and serious open-air waste-combustion accidents. Polychlorinated biphenyls (PCBs) in milk samples were also studied. Breast milk was also monitored in two cities in northern Italy, Milan and Piacenza, which were selected as controls. Other variables, such as diet and age of the mothers, were also studied. PCDD/F and PCB levels and congener profiles in breast-milk samples were similar in all these cities, though total PCDD/F and DL-PCB TEQs in samples from Giugliano were significantly lower than those in Milan and Piacenza (8.65 pg WHO-TEQ in Giugliano vs. 11.0 and 9.94 pg WHO-TEQ in Milan and Piacenza respectively). Thus no direct correlations were found between PCDD/F and PCB levels in breast milk and the suspected increased exposure through open-air waste combustion in Giugliano. Diet did not seem to affect PCDD/F and PCB levels, whereas a significant correlation was observed between the mother's age and an increased concentration of PCDDs/Fs and PCBs in milk. Comparison of these findings with those of previous surveys in Italy in 2000-2001 showed a marked reduction of PCDD/F (about 60%) and DL-PCB (about 20%) levels in breast milk occurring over the last 10 years. This might well be a result of well functioning legislation, for example European Directives on of the reduction of the emission limits of PCDDs/Fs and PCBs from waste incineration set by EU Directive 2000/76/EC implemented in 2000, or Commission Regulations such as (EC) No. 466/2001 and 1881/2006 setting maximum levels for certain contaminants in foodstuffs.

Persistent Organochlorine Exposure and Pregnancy Loss: A Prospective Cohort Study

Polychlorinated biphenyls (PCBs) and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) are suspected reproductive toxicants. We assessed serum concentration of 76 PCB congeners, DDE, and risk of human chorionic gonadotropin confirmed pregnancy loss among 79 women followed for up to 12 menstrual cycles or until pregnancy. 55 women had live births, 14 experienced pregnancy losses, and 10 did not achieve pregnancy. PCBs and DDE were quantified using gas chromatography with electron capture. PCBs were grouped a priori by biologic activity. Cox proportional hazard regression adjusting for age (categorized 24 - 29, 30 - 34) and average standardized alcohol and cigarette intake (continuous) was used to estimate hazard ratios (HR) of pregnancy loss. Estrogenic PCBs (HR = 1.66, 95% CI: 0.68, 4.02), anti-estrogenic PCBs (HR = 0.10, 95% CI: <0.01, 67.07) and DDE (HR = 1.43, 95% CI: 0.45, 4.52) were not statistically significantly associated with pregnancy loss. Our results provide some signal that estrogenic and antiestrogenic PCBs may be differentially associated with pregnancy loss. Further research is needed to elucidate these associations.

Negative associations between PBDE levels and thyroid hormones in cord blood

Polybrominated diphenyl ethers (PBDEs) causing thyroidal effects have been demonstrated in in vivo and in vitro studies. PBDEs with structural similarities to thyroid hormones have increased recently, but the health effects for thyroid hormones have not been well studied. The study aimed to determine PBDE levels in cord blood and further to explore associations between prenatal PBDE exposures and thyroid hormones in cord blood. Fifty-four cord blood samples were collected after delivery. Cord-blood levels of BDE-15, 28, 47, 99, 100, 153, 154, and 183 were analyzed using a high resolution gas chromatograph with a high resolution mass spectrometer. Thyroid hormones were determined by an automated chemiluminescence analyzer. The mean, median, and standard deviation of ΣPBDEs were 4.72, 3.49, and 6.36 ng/g lipid, respectively. To adjust for confounding by maternal age, pre-pregnant BMI and gestational age, stepwise multiple linear regression was used after log(2) transformation of the exposure variables. A doubling of BDE-154 was associated with 0.043 ng/mL lower triiodothyronine (T3) values (adjusted r=-0.245, p=0.043). Likewise a doubling of BDE-153 was associated with 0.143 ng/mL lower free T3 (FT3) values and a doubling of BDE-183 with 0.084 ng/mL lower FT3 values (adjusted r=-0.487, p=0.023). In contrast, the T4 (thyroxine)/T3 ratio increased by 4.93 (adjusted r=0.277, p=0.017) when doubling BDE-100 exposure. No significant associations with BDE-47 or any other of the PBDEs was found. Our findings of an inverse relationship between BDE-153, BDE-154 or BDE-184 and thyroid hormones confirm the results of animal experiments but are in contrast to most epidemiological studies.

Dietary exposure to PCBs based on food consumption survey and food basket analysis at Taizhou, China--the world's major site for recycling transformers

The levels of PCBs in different types of food (fish, shellfish, meat, rice, vegetables, and fruits) were analyzed to determine the dietary intake of 37 PCBs for local residents and e-waste workers (all lactating mothers) at Taizhou (China), a major electronic waste scrapping center, in particular for recycling transformers. The exposure to PCBs through dietary intake in Taizhou was estimated at 92.79 ngkg(-1)d(-1), contributed by consumption of freshwater fish (28%), rice (28%), meat (17%), shellfish (9%), vegetables (8%), egg (4%) and marine fish (2%). With regards to WHO-PCB-TEQ values, freshwater fish (40%), shellfish (24%), duck liver (18%) and rice (12%) were the main dietary sources with total daily intake (9.78 pg WHO-PCB-TEQ kg(-1)d(-1)), exceeding the FAO/WHO Tolerable Daily Intake (70 pg TEQkg(-1)body(-1)wt(-1)month(-1)).

Environmental and human exposure to persistent halogenated compounds derived from e-waste in China

Various classes of persistent halogenated compounds (PHCs) can be released into the environment due to improper handling and disposal of electronic waste (e-waste), which creates severe environmental problems and poses hazards to human health as well. In this review, polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls (PBBs), tetrabromobisphenol A (TBBPA), polybrominated phenols (PBPs), polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs), and chlorinated polycyclic aromatic hydrocarbons (ClPAHs) are the main target contaminants for examination. As the world's largest importer and recycler of e-waste, China has been under tremendous pressure to deal with this huge e-waste situation. This review assesses the magnitude of the e-waste problems in China based on data obtained from the last several years, during which many significant investigations have been conducted. Comparative analyses of the concentrations of several classes of toxic compounds, in which e-waste recycling sites are compared with reference sites in China, have indicated that improper e-waste handling affects the environment of dismantling sites more than that of control sites. An assessment of the annual mass loadings of PBDEs, PBBs, TBBPA, PBPs, PCDD/Fs, and ClPAHs from e-waste in China has shown that PBDEs are the dominant components of PHCs in e-waste, followed by ClPAHs and PCDD/Fs. The annual loadings of PBDEs, ClPAHs, and PCDD/Fs emission were estimated to range from 76,200 to 182,000, 900 to 2,000 and 3 to 8 kg/year, respectively. However, PCDD/Fs and ClPAHs should not be neglected because they are also primarily released from e-waste recycling processes. Overall, the magnitude of human exposure to these toxics in e-waste sites in China is at the high end of the global range.

Concentrations of polybrominated diphenyl ethers in breast milk correlated to maternal age, education level, and occupational exposure

The aim of the present study is to determine whether levels of polybrominated diphenyl ethers in breast milk in the general population are associated with demographic parameters, socioeconomic status, lifestyle factors, and occupational exposure. Forty-six participants are randomly selected from healthy women recruited between April 2007 and April 2008 from local hospitals in southern Taiwan. Thirty PBDE isomers in breast milk are analyzed using a gas chromatograph with a high resolution mass spectrometer. The mean+/-standard deviation of Sigma PBDEs in breast milk is 3.59+/-1.07 ng/g lipid. Our current value of Sigma PBDEs in breast milk is 0.7-fold lower compared to the past value in our previous study between 2000 and 2001. Higher levels of Sigma PBDEs might be significantly associated with older maternal age and maternal age of the present study is between 22 and 42 years old. Levels of Sigma PBDEs and certain PBDEs in breast milk are not correlated with maternal pre-pregnant BMI (Body mass index), parity, and lipid contents of breast milk. The Sigma PBDEs level in breast milk is lower in more educated women after controlling for age and pre-pregnancy BMI in our subjects. The main factors associated with Sigma PBDEs in breast milk are age and education level among the binary variables of demographic, socioeconomic, and lifestyle characteristics in this report. The exploratory relationships are found between PBDEs in breast milk and age, education level, or occupational exposure due to small sampling size.

Growth and thyroid function in children with in utero exposure to dioxin: a 5-year follow-up study

Because placental polychlorinated dibenzo-p-dioxins,dibenzofurans (PCDD/Fs) levels are associated with decreased free thyroxine (FT(4)) and thyroid stimulating hormone (TSH) in neonates, we assessed development by gender and maternal PCDD/Fs exposure at years 2 and 5 in 92 mother and newborn pairs. RIA quantified thyroid, sex, and growth hormones. Of 200 subjects followed up from November 2000, 136 and 149 were observed at year 2 and year 5,respectively. PCDD/Fs exposure levels were low (n = 35) or high (n = 35) in 70 subjects at year 2, low (n = 21) or high (n = 20) in 41 at year 5. Height, weight, BMI, and head circumference were significantly higher in males, chest girth significantly higher in females at year 2. Significantly, more girls had higher bone age (BA) and chronological age (CA) at both times. Height, weight, FT(4) x TSH, and transthyretin(TTR) at year 2; and height, triiodothyronine, and IGF-1 at year 5 differed significantly by PCDD/Fs level. In females, height, weight, CA,BA, and thyroid hormones differed significantly at year 2. In males, FT(4) x TSH at year 2 and IGF-1 at year 5 were significantly higher in the high PCDD/Fs group. In utero exposure to PCDD/Fs differentially affects growth and hormone levels in male and female preschool children.

Evaluation of background persistent organic pollutant levels in human from Taiwan: polychlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyls

This study was intended to determine the background levels of PCDD/PCDFs and PCBs in the Taiwanese population and to investigate factors potentially related to PCDD/PCDF and PCB levels. The levels of seventeen PCDD/PCDFs in the 251 serum samples collected from the general population in Taiwan ranged from 4.92 to 26.7 pg WHO(1998)-TEQ/g lipid (median: 11.5) and those of the twelve dioxin-like PCBs ranged between 1.74 and 21.6 pg WHO(1998)-TEQ/g lipid (median: 6.14). Five factors, age, gender, region of residence, dietary status, and smoking status, showed statistically significant association with the TEQ level of PCDD/PCDFs. The TEQ level of PCBs was statistically associated with age only, but not with the other four factors. The trends observed between age and the levels of PCDD/PCDFs and PCBs were not parallel in young subjects (<30 years old) and old subjects (>30 years old). The levels of PCDD/PCDFs and PCBs increased by 0.16 and 0.03 WHO(1998)-TEQ/g lipid per year for subjects above the age of 30, but there was no evidence of any association between age and the levels for subjects below the age of 30 years. These factors should be considered when investigating relationships between background serum levels of persistent organic pollutants and parameters associated with exposure sources or health outcomes.

Influence of PCB153 on oxidative DNA damage and DNA repair-related gene expression induced by PBDE-47 in human neuroblastoma cells in vitro

We studied the relationship between 2,2,4,4-tetrabromodiphenyl ether (PBDE-47) and oxidative DNA damage as well as the mode of interaction between PBDE-47 and 2,2,4,4,5,5-hexachlorobiphenyl (PCB153) by incubating SH-SY5Y cells in four doses of PBDE-47 (0, 1, 5, 10 microM) and/or 5 microM PCB153 and 100 microM NAC (N-acetylcysteine) for 24 h. Results showed that reactive oxygen species (ROS) production in the 5 microM PBDE-47 + PCB153 and 10 microM PBDE-47 + PCB153 groups were significantly higher than that of the control group (p < 0.05). DNA strand breakage and 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels were significantly increased in the 10 microM PBDE-47, 5 microM PBDE-47 + PCB153, and 10 microM PBDE-47 + PCB153 groups compared with the control (p < 0.05). Furthermore, ROS formation and DNA strand breakage were dramatically increased in the 5 microM PBDE-47 + PCB153 and 10 microM PBDE-47 + PCB153 groups compared with the corresponding PBDE-47 only group and the PCB153 group (p< 0.05). The level of 8-OHdG was significantly increased in the 10 microM PBDE-47 + PCB153 group compared with the corresponding PBDE-47 only group and the PCB153 group (p < 0.05). The PBDE-47 group coincubated with NAC decreased the ROS level and ameliorated PBDE-47-mediated DNA damage. The mRNA expression levels of X-ray repair cross-complementing gene 1 (Xrcc1) were significantly decreased in the 10 microM PBDE-47, 5 microM PBDE-47 + PCB153, and 10 microM PBDE-47 + PCB153 groups, whereas X-ray repair cross-complementing gene 3 (Xrcc3) were significantly increased in the 10 microM PBDE-47 and 10 microM PBDE-47 + PCB153 groups compared with the control (p < 0.05). The PBDE-47 groups coincubated with NAC, however, considerably increased Xrcc1 while decreasing Xrcc3 mRNA expression (p < 0.05). These results indicate that PBDE-47 induced oxidative DNA damage and that PBDE-47 combined with PCB153 may increase such effects in SH-SY5Y cells in vitro. Furthermore, our results suggest that oxidative stress is responsible for DNA damage induced by PBDE-47.

Polychlorinated dibenzo-p-dioxins and dibenzofurans pollution in China: sources, environmental levels and potential human health impacts

This review represents an assessment of the pollution status of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in China (the mainland, Hong Kong and Taiwan). During the past decades, seven PCDD/Fs pollution hotspots have been found: (a). Ya-er Lake, Hubei Province, with 'total PCDD/Fs' level reaching 177,427 pg g(-1) (dry weight) in lake sediments; (b). Chinese Schistosomiasis affected areas of Jiangxi Province with 33,660 pg g(-1) in soil; (c). e-waste recycling area of Yangtze River Delta, with 2726 pg g(-1) in paddy soil; (d). e-waste recycling area of Guiyu (eastern part of Guangdong Province), with 967,500 pg g(-1) in mixture of burnt residue and soil (the highest level among all hotspots); (e). Pearl River Delta with 2630 pg g(-1) in coastal sediment. (f). Kwun Tong, Victoria Harbour, Hong Kong with 10,999 pg g(-1) in coastal sediment; and (g). southern Taiwan with 606,000 pg g(-1) in soil near the vicinity of a pentachlorophenol manufacturing factory. The main sources of PCDD/Fs in China were formed from impurities during the production of polychlorophenol, hexachlorobenzene, polychlorinated biphenyls, organic chlorinated pesticide and triclosan. In addition, sources of PCDD/Fs included municipal waste incineration, mineral fuel usage, open burning of electronic waste and crop residues, industrial waste discharge and vehicle exhaust emission. Due to potential human health risks from long-term exposure to PCDD/Fs at these hotspots, body loadings of these contaminants should be monitored.

Relationship of thyroid hormone levels to levels of polychlorinated biphenyls, lead, p,p'- DDE, and other toxicants in Akwesasne Mohawk youth

BACKGROUND

It is well documented that acute exposure to high levels of persistent organic pollutants, such as polychlorinated biphenyls (PCBs), p,p'-dichlorophenyldichloroethylene (p,p'-DDE), and hexachlorobenzene (HCB), can affect human health including thyroid function. Chronic exposure to multiple toxicants is common but difficult to analyze, and most prior studies have focused on adults or newborns, creating a gap in our understanding of multitoxicant effects among adolescents.

OBJECTIVE

We investigated whether levels of PCBs, p,p'-DDE, HCB, mirex, lead, and mercury reflecting past chronic exposure are associated with alterations in levels of thyroid-stimulating hormone (TSH), triiodothyronine (T(3)), total thyroxine (TT(4)), and free thyroxine (FT(4)) among older children and adolescents.

METHODS

The sample consists of youth from the Akwesasne Mohawk Nation (n=232) who reside in proximity to several industries that have contaminated the local environment. We used multiple regression analysis to examine the effect of PCB groupings, p,p'-DDE, HCB, lead, and mercury on thyroid hormones after adjusting for sociodemographic covariates and controlling for all other toxicants.

RESULTS

Exposure to PCBs affects the thyroid hormone profile in adolescents. The group of persistent PCBs was positively associated with TSH but inversely related to FT(4). Nonpersistent PCBs were significantly and negatively related to FT(4) only. HCB was negatively associated with T(4), and lead was positively associated with T(3). Breast-fed adolescents had higher levels of persistent PCBs and p,p'-DDE but not of nonpersistent PCBs or any other toxicant when compared with non-breast-fed adolescents. Though having lower levels of persistent PCBs and p,p'-DDE, non-breast-fed adolescents exhibited significant relationships between persistent PCBs and TSH and FT(4), but breast-fed adolescents did not. It appears that PCBs from breast milk obscure the relationship between prenatal PCB exposure and thyroid function by adding random variation in PCB levels.

CONCLUSION

Our results demonstrate a reduction in thyroid function in adolescents in relation to their current serum levels of PCBs. These observations are consistent with the hypothesis that pre-natal exposure to PCBs alters thyroid function in a long-lasting manner but does not exclude the possibility that postnatal exposure is influential also.

Occurrence of PCBs, PCDD/Fs, PBDEs and DDTs in Spanish breast milk: enantiomeric fraction of chiral PCBs

Concentrations and congener specific profile of DDTs, PCBs and PCDD/Fs have been determined in a number of Spanish breast milk samples. The concentrations found indicate a decreasing tendency compared to previous data from the 1990s. Mean concentrations of 238 ng/g fat weight, 111 ng/g fat weight and 82.1 pg/g fat weight were found for DDTs, PCBs and 2,3,7,8-PCDD/Fs, respectively. When the WHO-TEQs were calculated, PCDD/Fs was the family contributing with the highest percentage to the total (62-84%), followed by the non-ortho PCBs (10-25%) and the mono-ortho PCBs (5-24%). The congener specific accumulation patterns found were comparable to those reported in other studies in industrialised countries. In addition, the levels of 9 PBDEs congeners have been also determined in the breast milk samples. The concentrations ranged from 0.04 to 1.38 ng/g fat weight. The enantiomeric enrichment of a number of chiral PCBs in the breast milk samples, including congeners 84, 91, 95, 132, 135, 149, 171, 174, 176 and 183, has also been studied, for some of them for the first time in this matrix.

Recent global trends and physiologic origins of dioxins and furans in human milk

Restrictions on releases of polychlorinated dibenzo-dioxins and polychlorinated dibenzofurans (PCDDs/Fs) to the environment from industrial practices have resulted in an attendant decrease in levels of these compounds in the environment. Continued environmental monitoring and biomonitoring of PCDDs/Fs ensure that exposures do not increase unexpectedly or unnoticed. Perhaps the most highly exposed part of the population, however, is the breastfed infant and a periodic assessment of levels of dioxins and furans in human milk provides exposure information for infants. A previous international review of levels of PCDDs/Fs in human milk based on data from the 1970's to the mid-1990's showed a decline in many countries for which data were available. In this paper, recent (1998-2005) global data on PCDDs/Fs in human milk are described. A comparison of these recent data to pre-1998 data suggests a continuing decline in global levels of PCDDs/Fs in human milk. In addition, this paper explores research on physiological origins of these compounds in human milk (e.g., adipose tissue mobilization, recent dietary exposures). The question of whether the presence of PCDDs/Fs in milk is from the lifetime accumulation of PCDDs/Fs in adipose tissue or current diet (or, as is more likely, a complex combination of both) remains unanswered. Whether diet during lactation has a greater influence on milk levels PCDDs/Fs levels than previously suspected, and whether infant exposures to PCDDs/Fs via breastfeeding could be reduced by changes in diet during lactation, are important--and currently unexplored--lines of inquiry.

Associations of diet with body burden of dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (PCBs): Observations on pregnant women from central Taiwan

The aim of this study was to examine the relationship between placental polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/F) and polychlorinated biphenyls (PCBs) toxic equivalent (TEQ) levels and the consumption of various food types in pregnant women from central Taiwan. Placental PCDD/Fs and PCB congener TEQ levels were evaluated in 109 pregnant women and dietary information was obtained by questionnaire. TEQ levels of PCDD/Fs and PCBs were positively associated with age and annual family incomes (p < 0.05). PCDD/F TEQs were significantly associated with freshwater fish and dairy product consumption after adjustment for age and body mass index (BMI) (p < 0.05). For PCB TEQs, significant associations were detected for saltwater fish consumption (p < 0.05). In summary, positive correlations were found between freshwater fish and dairy product intake and PCDD/F levels, and a marginal correlation between saltwater fish intake and the body burden of PCBs in pregnant women from central Taiwan. Risk assessment of PCDD/Fs and PCB in fishery products is warranted in a future study to quantify the benefits of fish consumption during the perinatal period.

Polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in milk from Italian women living in Rome and Venice

The levels of selected polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) were measured in human milk samples from the areas of Venice and Rome, primarily in order to characterize the current levels of infant exposure to PCBs and PBDEs due to breast feeding in Italy. Sixteen non-dioxin-like PCBs, including the traditional indicator congeners, and 11 PBDEs, comprising the relevant PBDE-47, PBDE-99, and PBDE-153, were determined. Congeners were selected for analysis according to their relative abundance in human tissues, toxicological relevance, and diffusion in the environment. Dietary habits of the milk donors were recorded by questionnaires; mothers of the Venice area were classified into three groups according to their consumption of local fish, molluscs, and other fishery products. Sigma(16)(PCBs) and Sigma(11)(PBDEs) (ng g(-1) fat) for the areas of Venice and Rome were respectively, 250-390 and 240, and 1.6-2.8 and 4.1. An increase of fish and fishery product consumption could not be associated with an increase of PCB and PBDE levels in milk.

Evaluation of GC-ion trap-MS/MS methodology for monitoring PCDD/Fs in infant formulas

The application of high resolution gas chromatography in combination with low resolution mass spectrometry with electron ionization and MS/MS detection (HRGC-MS/MS) is tested for its use in the analysis of PCDD/Fs in infant formulas. Development of the analytical method was based upon EPA directrices and international recommendations. Calibration linearity was tested and average relative response for any native and labelled compound over the five-point calibration range below 14% was found. The precision and accuracy of the proposed analytical procedure are also presented. Results obtained are in agreement with EPA criteria. The method is applied to the analysis of a number of initial and follow-on milk based infant formulas. In general, HRGC-MS/MS constitutes an interesting method for the analysis of dioxins in such matrices.

Levels of polybrominated diphenyl ethers (PBDEs) in breast milk from central Taiwan and their relation to infant birth outcome and maternal menstruation effects

In utero exposure to polybrominated diphenyl ethers (PBDEs) reduces the number of ovarian follicles in rat females and causes permanent effects on rat males. Little data have been gathered on the associations between PBDEs exposure and birth outcome and female menstruation characteristics in both epidemiological and animal studies. The aim of this study was to examine how PBDEs in breast milk are associated with infant birth outcome and maternal menstruation characteristics. Study participants were healthy women recruited from central Taiwan between December 2000 and November 2001. Twelve congener levels of PBDEs (BDE-17, 28, 47, 66, 85, 99, 100, 138, 153, 154, 183, 209) in 20 breast milk samples were measured by gas chromatography with high resolution mass spectrometer. The mean level of PBDEs in breast milk was 3.93+/-1.74 ng/g lipid. The estimated PBDE daily intake for a breastfed infant was 20.6 ng/kg b.w./day after delivery. After maternal age, pre-pregnant BMI, and parity were adjusted, increased PBDEs in breast milk was related with decreased birth outcome, particularly for birth weight and length, chest circumference, and Quetelet's index of infants. No significant differences in PBDEs were found between the two groups of menstrual cycle length higher and lower than 30 days after we adjusted for maternal age, pre-pregnant BMI, and parity. In utero exposure to low doses of PBDEs may result in lower birth weight and short or birth length. Our findings are limited based on the low doses of PBDEs and the small sampling size.

Comparison of organochlorine compound concentrations in colostrum and mature milk

Human breast milk represents the best choice for the nutrition of infants. It is often used for monitoring human exposures to environmental chemicals. Uniquely suited to meet human biological needs, breast milk composition, especially fat content, changes significantly with time from delivery. With the aim to compare the concentration of organochlorine compounds (OCs) in colostrum versus mature milk, we obtained samples of fourth-fifth day postpartum milk (colostrum) and day-14 postpartum milk (mature milk) from 12 women enrolled in the project "Early Childhood Development and PCB Exposure in Slovakia". The concentrations of selected organochlorine pesticides and congeners of polychlorinated biphenyls (PCBs) were measured using gas chromatography with electron capture detection and reported on lipid adjusted basis. No significant differences were found between organochlorine levels in colostrum and those in mature milk samples. A very close correlation was found between the concentrations of organochlorine compounds in colostrum and mature milk (Spearman correlation coefficient r=0.94-0.98 for PCBs, and r=0.85-0.99 for organochlorine pesticides, p<0.001 for all compounds). The present study concludes that the use of colostrum samples provides a close estimate of the child's exposure to OCs in the early neonatal period and demonstrates that, despite the lower fat content, colostrum specimens are adequate to conduct OC analyses.

A comparison of PCDD/PCDFs exposure in infants via formula milk or breast milk feeding

Food is the major source for polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) accumulation in human body. In infant period, breast milk and formula milk are the major food sources. Congener-specific analyses of 17 PCDD/PCDFs were performed on 10 brands of formula milk samples which were milk-based and 37 breast milk samples collected from women living in southern Taiwan. The levels of 17 PCDD/PCDFs in 10 formula milk samples ranged from 0.468 to 0.962 pg WHO-TEQ/g lipid, with a mean value of 0.713+/-0.163 pg WHO-TEQ/g lipid. For the 37 breast milk samples, their PCDD/PCDF levels were 14.7+/-9.36 pg WHO-TEQ/g lipid, with a range between 4.21 and 52.8 pg WHO-TEQ/g lipid. At 12th month of age for infants, average daily intakes (ADI) of PCDD/PCDFs were 2.1 pg WHO-TEQ/kg/day for the formula-feeding infants, and 13 pg WHO-TEQ/kg/day for the breast-feeding infants. The present data may provide useful information for risk-benefit evaluation of formula- and breast-feeding.

Body burden of dioxins and dioxin-like polychlorinated biphenyls in pregnant women residing in a contaminated area

A large pentachlorophenol (PCP)-manufacturing plant located in southwestern Taiwan operated between 1965 and 1982. The present study was conducted to ascertain whether an increased body burden of dioxins existed in pregnant women living in an area of Tainan city contaminated by chemicals from this plant. Twenty-eight pregnant subjects, 21-39 years of age and residing in the study area between March and December of 2004 with a mean dwelling time of 6.07+/-6.11 years, were recruited. Concentrations of polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs), and dioxin-like polychlorinated biphenyls (PCBs) in serum of recruited residents were determined. Pregnant women residing in the study area >3 years had significantly higher PCDD (7.48 versus 5.13 pg-toxic equivalents [TEQ]/g-lipid) and dioxin-like PCB (6.70 versus 3.74 pg-TEQ/g-lipid) values as compared to those residing < or = 3 years. Furthermore, dioxin concentrations increased with increasing dwelling time. Statistical analyses performed according to demographic characteristics and socioeconomic and dietary habits revealed that total TEQ values were significantly associated with fish consumption and smoking status. Dioxin congeners with greater degrees of chlorine substitution (e.g., HpCDD/F and OCDD/F) partitioned to greater degrees in the subjects of this study as compared to subjects in the general Taiwanese population. The findings of this study strongly implicate the activity of the PCP manufacturing plant in the observed increase in dioxin body burden. Investigation of the health consequences of this increased body burden is recommended.

Placental transfer of polychlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyls in Taiwanese mothers in relation to menstrual cycle characteristics

The aim was to determine the body burden of dioxins and polychlorinated biphenyls (PCBs) and whether they are associated with variables influencing reproduction. Our subjects were healthy women (mean age of 29 [SD=4.5]) from central Taiwan. The congeners of dioxins and dioxin-like PCBs in placentas (n=119) were identified using gas chromatography/high resolution mass spectrometry. The median levels of polychlorinated dibenzo-p-dioxins/dibenzofurans and PCBs were 10.2 (geometric mean [GM]: 9.8, 95% confidence interval [95% CI]: 8.8-10.9) and 2.7 (GM: 2.7, 95% CI: 2.3-3.1) pg WHO-TEQ/g lipid, respectively. Total TEQ level in placentas was significantly correlated with mothers' arm circumference (r=0.22, p=0.043). Increased body fat percentage was associated with higher total TEQ level in placentas. After adjustment for maternal age, pre-pregnant body mass index (BMI), and parity, placental dioxin-TEQ level higher in women (age 19 years) with irregular menstrual cycle than in those (age <18 years) with regular menstrual cycle (p=0.032) and placental PCB-TEQ level was higher in women with menstrual cycles longer than 33 days versus less than 33 days (p=0.006). Thus, environmental exposure to dioxins and PCBs may be related to changes in current menstrual cycle characteristics.

Overview of exposure, toxicity, and risks to children from current levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin and related compounds in the USA

Studies of children indicate that exposure of the general population to low levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) does not result in any clinical evidence of disease, although accidental exposure to high levels either before or after birth have led to a number of developmental deficits. Breast-fed infants have higher exposures than formula-fed infants, but studies consistently find that breast-fed infants perform better on developmental neurologic tests than their formula-fed counterparts, supporting the well-recognized benefits of breast feeding. Children receive higher exposures to PCDD/Fs from food than adults on a body-weight basis but those exposures are below the World Health Organization's tolerable daily intake. Laboratory rodents appear to be at least an order of magnitude more sensitive than humans to the aryl hydrocarbon receptor-mediated effects of these substances, which makes them poor surrogates for predicting quantitative risks but makes them good models for establishing safe levels of human exposure by organizations mandated to protect public health. Any exposure limit for PCDD/Fs based on developmental toxicity in sensitive laboratory animals can be expected to be especially protective of human health, including the health of infants and children. Because body burdens and environmental levels continue to decline, it is unlikely that children alive today in the USA will experience exposures to PCDD/Fs that are injurious to their health.

Body burdens of polychlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyls and their relations to estrogen metabolism in pregnant women

Polychlorinated dibenzo-p-dioxins (PCDDs, dioxins), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) are environmental endocrine disruptors that have half-lives of 7-10 years in the human body and have toxicities that probably include carcinogenesis. A high ratio of 4-hydroxyl estradiol (4-OH-E2) to 2-hydroxyl estradiol (2-OH-E2) has been suggested as a potential biomarker for estrogen-dependent neoplasms. In this cohort study of maternal-fetal pairs, we examined the relationship of PCDD/PCDF and PCB exposure to levels of estrogen metabolites in the sera of 50 pregnant women 25-34 years of age from central Taiwan. Maternal blood was collected during the third trimester, and the placenta was collected at delivery. We measured 17 dioxin congeners, 12 dioxin-like PCBs, and 6 indicator PCBs in placenta using gas chromatography coupled with high-resolution mass spectrometry. Estrogen metabolites in maternal serum were analyzed by liquid chromatography tandem mass spectrometry. The ratio of 4-OH-E2:2-OH-E2 decreased with increasing exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (beta=-0.124, p=0.004 by the general linear regression model, R=0.4). Meanwhile, serum levels of 4-OH-E2 increased with increasing concentrations of high-chlorinated PCDFs (i.e., 1,2,3,4,6,7,8-hepta-CDF: beta=0.454, p=0.03, R=0.30). Altered estrogen catabolism might be associated with body burdens of PCDDs/PCDFs. Our study suggests that exposure to PCDDs/PCDFs significantly affects estrogen metabolism. Therefore, PCDD/PCDF exposure must be considered when using the OH-E2 ratio as a breast cancer marker.

Levels of organochlorine pesticides in human milk from central Taiwan

The present study determined the residues of organochlorine pesticides (OCPs) in human milk collected in central Taiwan between December 2000 and November 2001. The OCPs were analyzed by GC/MS for 36 human milk samples from healthy women ranging between 20 and 36 years of age. The predominant OCPs were p,p'-DDE, p,p'-DDT, alpha-CHL, heptachlor epoxide, heptachlor, beta-HCH, and gamma-HCH, with median levels of 228, 19, 7.4, 4.0, 2.3, 1.2, and 0.8 ng/g lipid, respectively. The residues of OCPs in human milk from central Taiwan were comparable to those described in results from Sweden, the United Kingdom, and Japan, and were significantly lower than those from investigations in Asian countries, including China, Thailand, Indonesia, and Vietnam. Low DDE/DDT ratio (mean=13.6, SD=6.54) indicated that residual OCPs in human milk mainly originate from past exposure. A notable decrease in DDT levels ( sigma DDT=333 ng/g lipid) in human milk was found in this study compared to results from the previous two decades ( sigma DDT=3,595 ng/g lipid). Hypothetically, the level of alpha-CHL was significantly associated with total TEQ levels in Taiwanese human milk because of the sources of food contaminant, i.e. animal fat. Based on low OCP levels in Taiwanese human milk and low estimated median daily intake of total DDTs for a breastfed infant (1,358 ng/kg/day) with the assumption of an infant weighting 4 kg and consuming 699 g milk per day in the first month after birth, the Taiwanese policy of breast-feeding promotion was supported.