Levels of PCB 126 and PCB 153 in plasma and tissues in goats exposed during gestation and lactation

The aim of the present study was to gain knowledge about the disposition of the PCB congeners 126 and 153 in a goat model where pregnant does were given oral doses of PCB from day 60 of gestation until delivery. The goat kids were thus exposed to PCB during gestation and lactation. The doses of PCB 153 and PCB 126 were 98 and 49 ng/kg body wt/day, respectively. PCB levels were measured in plasma from the does at day 90 of gestation and at delivery, and in plasma from the kids at birth and four weeks post partum. Concentrations of PCB were analysed in brain, liver and fat tissue from the does six weeks after delivery and in liver and fat tissue from the kids at nine months of age. The ratio of estimated body burden to ingested dose in the does, was 0.95 +/- 0.07 for PCB 153 and 0.41 +/- 0.03 for PCB 126. Approximately 9% of PCB 153 and 6% of PCB 126 was transferred from the mothers to their kids during gestation and lactation. Prenatal exposure contributed to a much lower fraction of the body burden than postnatal PCB intake via milk, due to the fact that almost 100% of the PCB 153 transferred from the does to kids was transferred via milk, and the PCB 126 intake via milk was threefold higher than the calculated body burden. The hepatic PCB 126 concentration in both does and kids was significantly higher than the concentration in fat, in contrast to PCB 153, where the highest concentrations were found in fat. A significant difference in body burden between the does at delivery, the newborn kids, and the kids at four weeks of age, did not influence the plasma concentration of PCB 153 on a fat weight basis, which showed no difference with sampling time. Our results suggest that PCB 126 and PCB 153 have different pharmacokinetic properties. The higher levels of PCB 126 in liver tissue compared to fat tissue confirm the concept of hepatic sequestration. The similar blood concentration of PCB 153 in the does at delivery and their newborn kids despite the considerable difference in body burden, suggests a high degree of placental transfer. This supports previous observations that low molecular weight, lipid-soluble, non-polar chemicals reach the fetus to the greatest possible extent. For PCB 153, the body burden may provide the appropriate dose metric at steady state, but may give a minor underestimation of PCB 126 at low environmental exposure levels due to hepatic sequestration.     

PCDDs, PCDFs, and PCBs concentrations in breast milk from two areas in Korea: body burden of mothers and implications for feeding infants

We determined breast milk concentration of polychlorinated dibenzo-p-dioxins (PCDDs)/polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) in 24 mothers living in Korea, and assessed the maternal body burden based on PCDDs/PCDFs and PCBs concentrations in breast milk and an infant intake rate through breast-feeding based on their concentration in breast milk. PCDDs/PCDFs and PCBs levels in breast milk from primipara mothers were found to be higher than those from multipara mothers. For total PCDDs/PCDFs TEQ level, 2,3,4,7,8-PeCDD was the predominant congener, and the proportion of 2,3,7,8-TCDD was less than 3% of total PCDDs/PCDFs TEQ level. For PCBs TEQ level, PCB-126 was the predominant congener. Maternal body burden levels of PCDDs/PCDFs and PCBs based on their concentrations in breast milk were 268-622 TEQ ng. The daily dioxin intakes of mothers were predicted to be 0.78-2.18 TEQ pg/kg/day for PCDDs/PCDFs and 0.34-0.66 TEQ pg/kg/ day for PCBs. For the first year, the body burden of an infant was predicted to be 212 TEQ ng and the daily intake of an infant was predicted to be 85 TEQ pg/kg/day, assuming the mean dioxin-related compounds concentration (27.54 TEQ pg/g fat).     

Effects of dioxins and polychlorinated biphenyls (PCBs) on thyroid function in infants born in Japan – the second report from research on environmental health

Dioxins (PCDD + PCDF) and polychlorinated biphenyl (PCB) are potentially hazardous compounds and have structural similarity to thyroid hormones. Our research group on “Dioxins and PCB in Human Milk” was organized in 1997 and has been active for the past three years. We collected breast milk from 80 mothers living in Tokyo, Saitama, Ishikawa and Osaka Prefecture in Japan at 5, 30, 150, 300 postpartum days and measured PCDDs, PCDFs and PCBs during 1998–1999. We added another 20 prefectures and cities during 1999–2000. Breast milk was obtained from 415 mothers at 30 postpartum days (breast-feeding group). Blood was taken from infants who were breast-fed at the age of 1 year for evaluation of thyroid and immune functions. Blood was also taken from 53 infants who were bottle-fed (bottle-feeding group) as a control. Serum T4, T3, FT4 and TSH levels in the breast-feeding (n=337) and bottle-feeding (n=53) groups were within normal ranges and were not significantly different between the two groups. Although there were a large geographic differences of dioxins and co-PCB content in breast milk, there were no differences in serum T4, T3, FT4, TSH levels and no significant correlation between the mean serum levels of TSH and TEQ in breast milk. There was a significant correlation between serum TSH at 1 year of age and that from blood on dried filter paper TSH at 5 days of age. We concluded that dioxin intake from breast milk in Japanese infants did not impair thyroid function. However, long-term effects remain to be evaluated.     

Background levels of non-ortho-substituted (coplanar) polychlorinated biphenyls in human serum of Missouri residents

This study characterizes the levels of polychlorinated biphenyls (PCB) congeners PCB 77, PCB 81, PCB 126, and PCB 169, in a group of 150 men and women with no documented exposure to PCBs. Its purpose is to provide current referent levels of coplanar PCBs in Missouri residents and to compare those levels to levels reported in the literature from the United States and other countries. Although this study used an extensive questionnaire assessing potential sources of exposure, no positive relations were found between these exposure sources and participants' PCB levels. The PCB levels for the four congeners measured were lower than any reported in the literature. PCBs 126 and 169 are only two of the dioxin-like congeners; however, their contribution makes up 11% of the total TEQ. Age was significantly related to PCB 126 and PCB 169. For every one-year increase in age, both PCB congeners increased by approximately 0.4 parts per trillion (ppt). There was no gender difference for PCB 126; however, PCB 169 levels were 3 ppt higher in males than females.     

Dioxins in human milk and smoking of mothers

BACKGROUND: The relation between the levels of dioxins in human breast milk and the smoking habits of the mothers is controversial. To clarify this relationship, we analyzed data from the human milk survey in Japan. METHODS: The human milk survey has been conducted in Japan since 1997. Healthy pregnant women aged 20-39 years were recruited and 50 ml of breast milk was collected from them at 30 days after delivery. PCDDs, PCDFs, and dioxin-like PCBs were measured by using GC/MS. The smoking habits of the mothers were established by interviewing them soon after delivery and were classified into four categories: current smokers, ever smokers who quit smoking at the pregnancy, ever smokers who quit smoking before the pregnancy, and never smokers. The levels of dioxins in breast milk were compared in the four categories of smoking among 853 primiparas. In addition, we analyzed the association between dioxin levels and passive smoking among never smokers. The geometric means of the dioxin concentrations were calculated in order to compare the differences between dioxins. RESULTS: The geometric means of dioxin-like PCBs in milk of never smokers was the highest (9.2 pg TEQ/g fat); followed by ever smokers who quit smoking before the pregnancy, ever smokers who quit smoking at the pregnancy, and current smokers (7.5, 7.2, and 6.6 pg TEQ/g fat, respectively). The differences between these levels were statistically significant (ANOVA, p<0.001). No significant difference was observed between the level of dioxins in milk from never smokers subjected to passive smoking status and those who had not experienced passive smoking. CONCLUSION: The levels of dioxin-like PCBs in human milk were negatively related to the smoking habits of mothers.     

Levels of PCDDs, PCDFs, and PCBs in the blood of the non-occupationally exposed residents living in the vicinity of a chemical plant in the Czech Republic

In 2003, concentrations of altogether 17 PCDD/Fs congeners and 12 non-ortho and mono-ortho dioxin-like PCBs were measured in the blood of 60 randomly selected adults who lived in three settlements surrounding a chemical plant that had been producing chlorinated herbicides (mainly HCHs, HCB, pentachlorophenole, 2,4,5-T) in the 1960's; subjects consuming home-produced animal foods were chosen. Twenty blood donors with similar characteristics from the locality with about 80 km distance were used as control subjects. The factors that influenced the dioxin levels were investigated on the basis of a questionnaire. The aim of our study was to find out whether the residents living in the surroundings of the chemical plant are at a greater exposure risk than the controls. To calculate TEQ values, WHO-TEFs were used. The concentrations of four PCDD and six PCDF congeners were below the LOD in more than 50% of samples. Significantly higher WHO-TEQ levels (p<0.05) were found for PCDDs, PCDFs, or PCBs in all three followed up groups compared with controls. The geometric means of the total TEQ values for PCDD/F/PCBs were 43.8, 50.2, and 40.0 pg/g fat compared to 23.2 pg/g fat in the control. The percentages of TEQ due to the measured congeners in exposed groups were 9-10.3% for PCDDs, 20.5-26.9% for PCDFs, 19.2-23.1% for coplanar and 43.6-47.2% for mono-ortho PCBs. In control, the percentage of TEQ was 11.6, 26.7, 24.1, and 37.5%. PCBs, predominantly PCB156, followed by PCB126 contributed 60 to 70% of the total TEQ value. Positive correlation of the PCDD/PCDF/PCB blood levels with age and with consumption of locally produced eggs was found.     

Infant exposure to polychlorinated dibenzo-p-dioxins, dibenzofurans and biphenyls (PCDD/Fs, PCBs)--correlation between prenatal and postnatal exposure

Polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) are recognized environmental endocrine disruptors, which are environmentally persistent and may bio-accumulate in human bodies. Pregnant and nursing women may pass these pollutants to their babies both trans-placentally and lactationally. We measured and examined correlations of the levels of PCDD/Fs and PCBs in perinatal venous serum, placenta, umbilical-cord serum (representing prenatal exposure), and breast milk (postnatal exposure). Subjects included pregnant women without clinical complication between the ages of 25 and 35, who delivered their babies during 2000.12.01 and 2001.11.30 in central Taiwan. A total of 20 participants were randomly selected from those provided the four biological specimens for analysis of 17 PCDD/Fs, and 12 dioxin-like PCBs and six indicator PCBs using high-resolution gas chromatography/high-resolution mass spectrometry. Higher PCDD/F levels were found in placenta (10.3 TEq-pg/g lipid) and venous serum (9.1 TEq-pg/g lipid) compared to those in breast milk (7.6 TEq-pg/g lipid). Pearson and Spearman correlation analyses showed well association of PCDD/F and PCB levels between different specimens. The total dioxin/PCB level in milk, venous and cord serum can be well predicted by that in placenta through regression functions. This first study of multi-specimen correlation further established rather consistent ratios of these chemical concentrations in various specimens relative to those in venous serum.     

Longitudinal increases in PCDD/F and dl-PCB concentrations in human milk in northern China

There is a dearth of information on the temporal changes in polychlorinated dibenzodioxin/furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) contamination, in both environmental and biological specimens, in China. We compared the concentrations of PCDD/Fs and dl-PCBs in human milk collected in Shijiazhuang, Hebei Province, in northern China in 2002 (n=30) and 2007 (n=20). The level of PCDD/Fs and dl-PCBs showed an increasing trend. The mean concentrations of PCDD/Fs plus dl-PCBs were 4.47 TEQ pg g(-1) fat and 6.24 TEQ pg g(-1) fat in human milk from Shijiazhuang in 2002 and in 2007, respectively. Based on statistical analysis of questionnaire data collected by in-person interviews with mothers, we found positive correlations between consumption of sea fish and PCDFs. The PCDDs, PCDFs, PCDD/Fs, and PCDD/Fs plus dl-PCBs levels in individuals consuming greater amounts of sea fish were higher than those consuming less sea fish, both with and without adjustments for potential confounding factors. Among 17 congeners of PCDD/Fs, the 2,3,7,8-TCDF, 1,2,3,7,8-PeCDF, 2,3,4,7,8-PeCDF, 1,2,3,4,7,8-HxCDF, 1,2,3,6,7,8-HxCDF, and 2,3,4,6,7,8-HxCDF congener concentrations in 2007 increased 134%, 55%, 53%, 57%, 65% and 130% when compared to 2002 levels, respectively. The 2007 dl-PCB congener levels were greater than those of the 2002 samples, with the exception of PCB81 and PCB77. Specifically, PCB105, PCB114, PCB118, PCB123 and PCB156 had increased greater than twofold from 2002 to 2007. Continuous surveillance of PCDD/F and dl-PCB levels in human milk is needed to accurately evaluate both environmental contamination and the human health risk to neonates in China.     

Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in breast milk from the Pacific Northwest

Breast milk samples from 40 first-time mothers from the Pacific Northwest of the US and Canada were analyzed for polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs). Total PBDEs (summation operator PBDEs), calculated by summing values for the 12 PBDEs congeners analyzed, ranged from 6 to 321 ppb (lipid weight) (mean=96 ppb; median=50 ppb). In approximately 40% of the women (15/40), summation operator PBDEs>100 ppb lw in their milk, and four samples had levels >250 ppb lw. PBDE 47 was the dominant congener in most samples, whereas PBDE 153 was predominant in a few (3/40). summation operator PCBs were calculated by summing values for the 82 PCB congeners analyzed, and ranged from 49 to 415 ppb (lipid weight) (mean=147 ppb; median=126 ppb). approximately 30% of the mothers (13/40) have summation operator PBDEs> summation operator PCBs in their milk samples, and approximately 65% (25/40) have BDE 47>PCB 153 in breast milk samples, with BDE 47 averaging 3-fold greater levels than PCB 153. Clearly, the lower brominated PBDEs are surpassing PCBs as a major environmental concern in North America, and are likely affecting significant portions of the populations in these regions. PBDEs have become a major persistent organic pollutant. However, there are no positive correlations between levels of summation operator PBDEs and summation operator PCBs, or between levels of PBDE 47 and PCB 153, suggesting there may be some differences in exposure pathways for PBDEs and PCBs in humans.     

Dioxin concentration in human milk in Hebei province in China and Tokyo, Japan: potential dietary risk factors and determination of possible sources

Very limited information is available on body burdens and environmental levels of dioxins and dioxin-like PCBs (dl-PCBs) in mainland China. In the current studies, human milk samples were collected from 30 breastfeeding mothers in Shijiazhuang city (industrialized) and 11 in the Tanshan countryside (agricultural) of Hebei Province in northern China. An additional 20 samples were obtained from mothers in Tokyo, Japan. PCDDs, PCDFs, and dl-PCBs in human milk were analyzed by high-resolution gas chromatography/high-resolution mass spectrometry. Our results show that arithmetic means for body burdens of PCDDs/Fs and dl-PCBs in Hebei were 3.6 and 1.9 pg TEQ g⁻¹ fat, respectively, which were only about one fourth of the levels in Japan. In addition, no difference was found in the chemical levels except dl-PCBs between the urban and rural areas. Based on the results of an in-person interview of the Chinese mothers using a 59-item questionnaire, freshwater fish consumption was found to correlate with the body burden of dioxins. Principal component analysis of dioxin congeners revealed that the patterns of dioxins in the Hebei urban and rural areas are quite similar; however, they are clearly different from those in Japan. Collectively, our results suggest that the lower body burdens of dioxin in Hebei may be due in part to the relatively slow industrialization and a lower consumption of marine foods. Finally, the results indicate that comprehensive monitoring of dioxins and dl-PCBs in humans as well as in the environment and foods is necessary in China.     

Concentrations of polychlorinated dibenzo-p-dioxins, dibenzofurans and non-ortho substituted biphenyls in polar bear milk from Svalbard (Norway)

Polychlorinated dibenzo-p-dioxins (PCDD), dibenzofurans (PCDF) and non-ortho substituted biphenyls (PCB, CB) were determined in 6 polar bear milk samples from Svalbard (Norway). For these compounds, no data for polar bears have been reported before from this region. Most of the PCDD/PCDF congeners were found at detectable levels. Concentrations expressed as 2,3,7,8-TCDD equivalents (Nordic model) were in the order of 1–3 pg/g⁻¹ fat (0.2–1.6 pg ml⁻¹ milk) which is comparable with ringed and harp seal blubber from the same region. On whole milk basis, concentrations were similar to those found in human milk. An estimation of the daily uptake via milk showed that the intake is lower for polar bears compared to humans. As in human milk, relatively high levels of OCDD were found in some polar bear milk samples. The PCDD/PCDF congener pattern in the milk was different to that found in polar bear fat from the Canadian Arctic. Non-ortho substituted PCB levels in polar bear milk were similar to those found in polar bear fat from the Canadian North. However, CB 77 or 169 dominated in the milk while CB 126 was the most abundant congener in fat. PCDD/PCDF levels expressed as 2,3,7,8-TE were highly correlated with the fat content of the milk. No correlation between CB and PCDD/PCDF concentrations was found. Some data indicate that PCDD/PCDF concentrations in polar bear milk decrease with increasing time after delivery.     

Assessment of dietary exposure to PCDD/F and dioxin-like PCB in infant formulae available on the EU market

In infant period, human milk and infant formulae are the major sources of exposure to dioxins (polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (PCB). Since in many parts of Europe the mothers are increasingly reluctant to breastfeed their babies, the main objective of the present study is to assess the level of exposure of non-breast-fed infants during their early development. Consequently, the concentration levels of PCDD/F and dioxin-like PCB were determined in industrial infant formulae including "starting" (aged 0-4months) and "follow-on" (after 4months) products of milk formula, soy formula and hypoallergenic infant formula, available on the EU market. Furthermore, dietary exposure to dioxin of exclusively formula-fed infants was assessed at each month from 0 to 9months. The results suggest that dietary exposure to dioxins via formulae is higher when consuming "starting" than "follow-on" infant formulae on a body-weight basis. Estimated dietary exposure after 4months of age was always below the lowest range of the Tolerable Daily Intake (TDI) of 1pg WHO-TEQkg(-1)bwd(-1) and Provisional Tolerable Monthly Intake (PTMI) of 70pg WHO-TEQkg(-1)bwmonth(-1). The highest estimated cumulative dietary exposure to PCDD/F and dioxin-like PCB was obtained considering infants of 0-1months fed with the "starting" hypoallergenic infant formula (2.8pg WHO-TEQkg(-1)bwd(-1) and 84pg WHO-TQkg(-1)bwmonth(-1)). However, these elevated levels are much lower than those observed in some studies in breast-fed infants. The study can be used for further risk assessments in regard to infant exposure.     

Comparison of the concentrations of polychlorinated biphenyls and dioxins in mothers affected by the Yusho incident and their children

Accumulated maternal dioxins are passed onto the fetus and neonate via the placenta and maternal milk. In Japan in 1968, an accidental human exposure to rice oil contaminated with polychlorinated biphenyls (PCBs) and other dioxin-related compounds, such as polychlorinated dibenzofurans (PCDFs), led to development of Yusho oil disease. We investigated differences in blood dioxin concentrations in mother-children pairs affected by the Yusho incident. From 2002 to 2008, blood samples were collected from 26 pairs of Yusho mothers and their children (19 mothers, 26 children). Specific congeners of seven polychlorinated dibenzo-p-dioxins (PCDDs), ten PCDFs, and four non-ortho PCBs were analyzed. The children had significantly lower TEQ concentrations of PCDDs, PCDFs, and coplanar PCBs compared to their mothers. The mother-child difference in blood concentrations varied with the congeners; the largest for 2,3,4,7,8-pentaCDF and the smallest for 1,2,3,4,6,7,8-heptaCDD. The level for 2,3,4,7,8-pentaCDF, which characterizes Yusho oil disease, was approximately 17-30 times higher in the mothers than in the general population, whereas there were no significant differences between children in the formula-fed group and the general population. In contrast, the mean level for 2,3,4,7,8-pentaCDF in the breast-fed group was approximately 1.5 times, (range 0.5-6.5 times) higher than that in the general population. Over 30 years after the Yusho incident, the mean blood dioxin levels in the offspring were only a fraction of the levels in their mothers. This is more consistent with exposure via breast milk than via transplacental transfer in the Yusho incident.     

Maternal-fetal distribution and transfer of dioxins in pregnant women in Japan, and attempts to reduce maternal transfer with Chlorella (Chlorella pyrenoidosa) supplements

Dioxins can be transferred from mother to fetus via the placenta, or to nursing infants via breast milk, potentially causing developmental health problems in children. To assess pediatric health risks from dioxins, exposure of mothers and children to dioxins must be clarified. Methods of reducing maternal transfer of dioxins should also be investigated. Concentrations of 28 dioxin (polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and co-planar polychlorinated biphenyls) congeners in blood, adipose tissue, breast milk, cord blood and placenta collected from 44 pregnant Japanese women were measured. In addition, to investigate potential reductions in maternal transfer of dioxins, 23 pregnant women were instructed to take Chlorella pyrenoidosa supplements during pregnancy. Correlations were observed between dioxin total toxic equivalents (total TEQ) in blood and total TEQ in adipose tissue (r=0.913, P<0.0001), breast milk (r=0.695, P=0.0007), and cord blood (r=0.759, P<0.0001). Dioxin levels transferred to fetuses and nursing infants reflect cumulative maternal concentrations of dioxins. A linear regression equation was introduced to predict total TEQ in breast milk and cord blood from dioxin levels in maternal blood, which should prove useful in evaluating fetal and infant risk of dioxin exposure. Total TEQ in cord blood were approximately 26% lower than in maternal blood (P<0.0001). The results of this study suggest that transplacental transfer differs depending on the dioxin congener. Total TEQ in breast milk were approximately 30% lower in the Chlorella group than in controls (P=0.0113). This finding suggests that maternal transfer of dioxins can be reduced using dietary measures such as Chlorella supplements.     

Congener profiles of PCDDs, PCDFs, and dioxin-like PCBs in the breast milk samples in Tokyo, Japan

Exposure to dioxins has raised much public concern recently. We determined the congeners' distribution of polychlorinated-dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in the breast milk samples collected in Tokyo, Japan. Breast milk was taken from 240 mothers, 30 days after delivery in 1999 and 2000 in Tokyo, Japan. The actual concentration and TEQ concentration of PCDDs (14 congeners), PCDFs (15 congeners), and dl-PCBs (12 congeners), and each congener's contribution to the total TEQ level were calculated. Among all the samples, PCDDs accounted for 34.8%, PCDFs accounted for 23.5%, dl-PCBs accounted for 41.7%, which was also similar in the breast milk from the primiparae and secundiparae. The main contributors to the total TEQ with increasing percentages were 2,3,4,7,8-PeCDF, 1,2,3,7,8-PeCDD and 3,3',4,4',5-PCB (#126), and they accounted for more than 65% of the total TEQ. Detailed congener analysis in breast milk samples is effective to understand dioxin sources.     

Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) in breast milk of first-time Irish mothers: impact of the 2008 dioxin incident in Ireland

The 2008 dioxin incident in Ireland resulted in elevated concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) in Irish pork and pork products, due to the consumption of contaminated animal feed by pigs. In order to investigate any resulting impact on the Irish population, these contaminants were measured in pooled breast milk samples from 109 first-time mothers, collected in 2010. A comparison of the results with similar data from 2002 revealed generally lower concentrations of PCDD/Fs and dioxin-like PCBs in the 2010 samples, confirming the declining trend reported by many authors. Contaminant concentration levels for both 2002 and 2010 were generally slightly lower than those reported internationally, with a mean combined PCDD/F and PCB WHO-TEQ of 9.66 pg g⁻¹ fat, for an overall pooled sample of milk from 2010. An apparent slight increase in PCDFs was observed between 2002 and 2010 (from 2.73 pg WHO-TEQ g⁻¹ fat to 3.21 pg WHO-TEQ g⁻¹ fat), with the main contributory congener being 2,3,4,7,8-PentaCDF. While it cannot be totally discounted that the slight increase in 2,3,4,7,8-PentaCDF and in the overall PCDF WHO-TEQ in breast milk could be attributable to consumption of Irish pork during the 2008 incident, we consider that it is more likely that this was due to other factors, including the predominantly urban/industrial sampling locations for the 2010 samples, compared to 2002.     

PCDD/F and dioxin-like PCB in human blood and milk from German mothers

Blood samples of pregnant women aged between 19 and 42 years at the time they gave birth and milk samples from the same women following delivery were collected between September 2000 and January 2003 from 169 participants living in an industrialized area of Germany (Duisburg birth cohort study). All samples were analyzed for their content of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) as well as dioxin-like and indicator polychlorinated biphenyls (PCB). Levels of WHO-TEq were in the range of 4.34-97.3 pg/g(lipid base) (median: 26.37, arithmetic mean: 28.36) for blood, or 3.01-78.7 pg/g(lipid base) (median: 26.40, arithmetic mean: 27.27) for milk, respectively. The four congeners 12378-PeCDD, 23478-PeCDF, 33'44'5-PeCB (# 126) and 233'44'5-HxCB (# 156) contribute the main share to total WHO-TEq. The contribution of PCDD/F in relation to PCB to total WHO-TEq was 60:40% in blood and 52:48% in milk. Good correlations of the contaminant levels in lipid base between both matrices were found. The distribution between blood and milk depends on the molecular weight of the substances. Higher chlorinated PCDD/F- and PCB-congeners were found in 2-4-fold higher concentrations in blood in relation to milk and the concentrations of lower chlorinated PCB-congeners were up to 2-fold higher in milk in relation to blood. The body burden of PCDD/F and PCB increases with age and decreases over the total nursing period. Women who had lived outside highly industrialized countries showed lower concentrations of PCDD/F and PCB. In some cases, elevated levels of PCB were observed when the women had previously lived in Eastern Europe for a long time. In comparison with recent data, the decline in human PCDD/F and PCB levels observed during the nineties seems to have stopped. The individual exposures of the infants due to breastfeeding within the first 18 months were calculated to be from 4.4 to 318 ng WHO-TEq (median: 106, arithmetic mean: 118). The actual mean daily exposure of a breastfed infant can be estimated to 131 pg WHO-TEq/kg(body weight).     

Concentrations of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and polychlorinated biphenyls in blood and breast milk collected from pregnant women in Sapporo City, Japan

We measured the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin-like polychlorinated biphenyls (PCBs), and non-dioxin-like PCBs in paired samples of blood and breast milk collected from 67 secundiparas in Sapporo City, Japan, and combined this data with those of the 30 secundiparas previously measured. The arithmetic mean total toxic equivalents (TEQ-WHO) concentrations of PCDDs, PCDFs, non-ortho PCBs, and mono-ortho PCBs in blood and breast milk of the 97 secundiparous subjects were 3.0-23 (mean: 13, median: 14) and 2.7-20 (mean: 8.6, median: 8.5) pg TEQ g⁻¹ lipid, respectively. The sums of the concentrations of 56 non-dioxin-like PCB congeners that were measured in the subjects’ blood and breast milk were 16-326 (mean: 107, median: 100) and 12-252 (mean: 73, median: 67) ng g⁻¹ lipid, respectively. The partitioning ratios of individual congeners of PCDDs, PCDFs, dioxin-like PCBs, and non-dioxin-like PCBs from blood to breast milk in secundiparas were almost the same as those of primiparas that have been recently reported, suggesting that the partitioning ratios of these compounds from maternal blood to breast milk in women is little affected by delivery. Furthermore, the partition of PCB congeners with chlorine at the 2-, 3-, 4′-, and 5-positions or the 2-, 4-, 4′-, and 5-positions of the biphenyl ring from the blood to the breast milk tended to occur at a higher level than that of other congeners. In particular, the levels of tetraCB-74 and hexaCB-146 in the breast milk for both primiparous and secundiparous mothers were slightly higher than those in the blood.     

Concentrations of polychlorinated dibenzo-p-dioxins,polychlorinated dibenzofurans,and polychlorinated biphenyls in blood and breast milk collected from pregnant women in Sapporo City,Japan

We measured the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin-like polychlorinated biphenyls (PCBs), and non-dioxin-like PCBs in paired samples of blood and breast milk collected from 67 secundiparas in Sapporo City, Japan, and combined this data with those of the 30 secundiparas previously measured. The arithmetic mean total toxic equivalents (TEQ-WHO) concentrations of PCDDs, PCDFs, non-ortho PCBs, and mono-ortho PCBs in blood and breast milk of the 97 secundiparous subjects were 3.0–23 (mean: 13, median: 14) and 2.7–20 (mean: 8.6, median: 8.5) pg TEQ g⁻¹ lipid, respectively. The sums of the concentrations of 56 non-dioxin-like PCB congeners that were measured in the subjects’ blood and breast milk were 16–326 (mean: 107, median: 100) and 12–252 (mean: 73, median: 67) ng g⁻¹ lipid, respectively. The partitioning ratios of individual congeners of PCDDs, PCDFs, dioxin-like PCBs, and non-dioxin-like PCBs from blood to breast milk in secundiparas were almost the same as those of primiparas that have been recently reported, suggesting that the partitioning ratios of these compounds from maternal blood to breast milk in women is little affected by delivery. Furthermore, the partition of PCB congeners with chlorine at the 2-, 3-, 4′-, and 5-positions or the 2-, 4-, 4′-, and 5-positions of the biphenyl ring from the blood to the breast milk tended to occur at a higher level than that of other congeners. In particular, the levels of tetraCB-74 and hexaCB-146 in the breast milk for both primiparous and secundiparous mothers were slightly higher than those in the blood.     

Occurrence of dioxins in cow's milk in the vicinity of municipal waste incinerators and a metal reclamation plant in the Netherlands

Over 200 samples of cow's milk have been analysed for dioxins in a survey on the occurrence of dioxins in milk from the vicinity of municipal waste incinerators (MSWs) and other potential dioxin sources in The Netherlands. Levels in milk were found to vary considerably with time, depending on emission rates, the direction and distance to the source and the feeding and housing of cows. Highest levels of up to 13.5 pg TEQ/g of milk fat were found in the Lickebaert area and Zaandam near two incinerators with highest emission rates. The background level ranged between 0.7 and 2.5 pg TEQ/g of milk fat. Levels in winter were comparable to those found in summer and, in some areas, even higher, when cows were fed with hay and silage harvested on the same farm. After the closure of the MSW in Zaandam, cow's milk from neighbouring farms showed a significant decrease in dioxin levels to below the critical limit of 6 pg TEQ/g of milk fat. Dioxin levels in the vicinity of a metal reclamation plant were comparable to those in milk from the vicinity of a MSW with moderate emissions. Differences were observed in the ratio PCDF/PCDD, which was higher in milk near the metal reclamation plant. Principal component analysis has been applied on a large data set of patterns of the 2,3,7,8-chlorine substituted PCDDs and PCDFs in cow's milk. This technique has proved to be useful for distinguishing and identification of sources on the basis of the isomer pattern in milk.