Polychlorinated biphenyls in adipose tissue, liver, and brain from nine stillborns of varying gestational ages.

We analyzed polychlorinated biphenyls (PCBs) in s.c. adipose tissue, liver, and brain of nine fetuses who died in utero. Their median (range) gestational ages and birth weights were 34 (17-40) wk and 2050 (162-3225) g. Three fetuses were small for gestational age. The levels of PCB congener nos. 118, 138, 153, and 180, and the sum of these (sigmaPCB), were calculated in terms of tissue total fat content (ng/g fat). The median (range) sigmaPCB (in ng/g fat) amounted to adipose tissue 235 (97-768), liver 198 (67-362), and brain 50 (22-122). Median (range) sigmaPCB levels in liver and brain were 0.8 (0.4-0.9) and 0.2 (0.1-0.3) times, respectively, as high as the sigmaPCB levels in adipose tissue. There were strong relations between sigmaPCB in adipose tissue and sigmaPCB in liver (r=0.98; p < 0.01), and between sigmaPCB in adipose tissue and sigmaPCB in brain (r=0.91; p < 0.01). Adipose tissue, liver, and brain did not show differences in the distribution of congeners 118, 138, 153, and 180, and there was no statistically significant association between tissue PCB levels and gestational age (r varied between 0.22 and 0.47). Median sigmaPCB levels in fetal adipose tissue proved to be comparable with our previously established sigmaPCB levels in mature breast milk of 93 Dutch women (median 414; range 158-969 ng/g of fat). The PCB congeneric distribution of fetal adipose tissue was not different from that of human milk. We conclude that maternal PCBs have a tendency to accumulate notably in fetal tissues with high triglyceride contents. They are easily transferred across the placenta and seem to become equilibrated among the apolar parts of maternal and fetal lipids.

Plasma polychlorinated biphenyl levels in Dutch preschool children either breast-fed or formula-fed during infancy.

OBJECTIVES: This study examined the influence of lactational and in utero exposure to polychlorinated biphenyls (PCBs) on plasma PCB levels in children. METHODS: Plasma PCB levels were measured in 173 children at 3.5 years, of whom 91 were breast-fed and 82 were formula-fed in infancy. RESULTS: Median plasma PCB levels were 3.6 times higher in breast-fed children (0.75 microgram/L) than in their formula-fed peers (0.21 microgram/L). Breast-feeding period and breast-milk PCB levels were important predictors for PCB levels in the breast-fed group. For children in the formula-fed group, PCB levels were significantly related to their material plasma PCB levels. CONCLUSIONS: PCB levels in Dutch preschool children are related to transfer of maternal PCBs; therefore, strategies should be aimed at reducing maternal PCB body burden.

Dietary intake of food contaminants in The Netherlands (Dutch Nutrition Surveillance System).

To assess the level of exposure to food contaminants (cadmium, lead, PCBs, DDT, hexachlorobenzene, nitrate and malathion) a total-diet study was carried out. A total of 226 food products were analysed individually; the concentration of contaminants in products not selected for analysis was estimated with the help of published data. The results of the analyses and estimations were used as input for the first Dutch National Food Consumption Survey (1987-1988) (n = 5898, age 1-85). Mean intakes of all contaminants analysed did not exceed the acceptable daily intake (ADI) or comparable values in any of the age-sex groups. Comparison of the results with those of previous total diet studies suggests that the intake of all contaminants analysed had declined between 1976-1978 and 1988-1989. In younger age groups an intake of lead and cadmium exceeding the tolerable daily intake (derived from the WHO/FAO provisional tolerable weekly intake) was found in 1.5% of individuals at most. For the older population groups and for the other contaminants in all population groups mean and maximum intakes were substantially below the ADL. However, individual intakes above the ADI for nitrate were found in 3-23% of individuals. For chronic exposure these percentages are likely to be overestimated because of the short time frame for food consumption measurement. In general, the difference between mean intake and tolerable daily intake was smallest for children aged 1-4. Therefore, it is recommended that future research is concentrated on the intake of contaminants in younger age groups.

Effects of polychlorinated biphenyl/dioxin exposure and feeding type on infants' mental and psychomotor development.

OBJECTIVE: To evaluate the effects of in utero and lactational exposure to polychlorinated biphenyls (PCBs) and dioxins on the mental and psychomotor development of infants. DESIGN: Prenatal PCB exposure was estimated from the levels in maternal plasma during the last month of pregnancy. Postnatal PCB and dioxin exposure of breastfed infants was calculated from levels in human milk samples and the duration of breastfeeding. Infants were examined at 3, 7, and 18 months of age with the Bayley Scales of Infant Development. SETTING: General community. PARTICIPANTS: Voluntary sample of 207 mother-infant pairs. One hundred five infants were breastfed and 102 were bottle-fed. INTERVENTIONS: None. RESULTS: Higher in utero exposure to PCBs was associated with lower psychomotor scores at 3 months of age: a doubling of the PCB load resulted in a decrease of 3 points. Breastfed infants scored significantly higher on the psychomotor score at 7 months of age, compared with formula-fed infants. However, when corrected for confounders, the psychomotor score of the 66% highest-exposed breastfed infants ( > 756 pg total PCB-dioxin toxic equivalent) was negatively influenced by this postnatal exposure to PCBs and dioxins, and was comparable to the psychomotor score of the formula-fed infants. Breastfed infants also scored higher on the mental scale at 7 months of age in a dose-dependent way. There was no significant influence of the perinatal PCB and dioxin exposure on the mental outcome at 3 and 7 months of age. At 18 months of age neither the mental nor the psychomotor score was related to perinatal PCB or dioxin exposure, nor to the duration of breastfeeding. CONCLUSIONS: Prenatal PCB exposure has a small negative effect on the psychomotor score at 3 months of age. PCB and dioxin exposure through breastfeeding has an adverse effect on the psychomotor outcome at 7 months of age. The mental outcome at 7 months of age is positively influenced by breastfeeding per se; the perinatal exposure to PCBs and dioxins does not influence this outcome. At 18 months of age the development is affected neither by PCB and dioxin exposure nor by feeding type.

Neurological condition in 18-month-old children perinatally exposed to polychlorinated biphenyls and dioxins.

The neurological optimality of 418 Dutch children was evaluated at the age of 18 months, in order to determine whether prenatal and breast milk mediated exposure to polychlorinated biphenyls (PCBs) and dioxins affected neurological development. Half of the infants were breast-fed, the other half were formula-fed. PCB concentrations in cord and maternal plasma were used as a measure of prenatal exposure to PCBs. To measure postnatal exposure, PCB and dioxin congeners were determined in human milk and in formula milk. After adjusting for covariates, transplacental PCB exposure was negatively related to the neurological condition at 18 months. Although greater amounts of PCBs and dioxins are transferred via nursing than via placental passage, an effect of lactational exposure to PCBs and dioxins could not be detected. We even found a beneficial effect of breast-feeding on the fluency of movements. We conclude that transplacental PCB passage has a small negative effect on the neurological condition in 18-month-old toddlers.

Perinatal exposure to polychlorinated biphenyls and dioxins and its effect on neonatal neurological development.

Polychlorinated biphenyls (PCBs) and dioxins (polychlorinated dibenzo-p-dioxins (PCDDs), and dibenzofurans (PCDFs)) are widespread environmental contaminants which are neurotoxic in animals. Perinatal exposure to PCBs, PCDDs, and PCDFs occurs prenatally via the placenta and postnatally via breast milk. To investigate whether such an exposure affects the neonatal neurological condition, the neurological optimality of 418 Dutch newborns was evaluated with the Prechtl neurological examination. Half of the infants were breast-fed, the other half were formula-fed, representing a relatively high against a relatively low postnatally exposed group, respectively. As an index of prenatal exposure, four non-planar PCBs in cord and maternal plasma were used. These PCB levels were not related to neurological function. As measures of combined pre- and early neonatal exposure, 17 dioxin congeners, three planar, and 23 non-planar PCB congeners were determined in human milk in the second week after delivery. Higher levels of PCBs, PCDDs, and PCDFs in breast milk were related to reduced neonatal neurological optimality. Higher levels of planar PCBs in breast milk were associated with a higher incidence of hypotonia. This study confirms previous reports about the neurotoxic effects of these compounds on the developing brain of newborn infants.

Cord blood levels of potentially neurotoxic pollutants (polychlorinated biphenyls, lead and cadmium) in the areas of Prague (Czech Republic) and Katowice (Poland). Comparison with reference values in The Netherlands. The Czech/Polish/Dutch/German Research Team.

In a preliminary study the levels of four non-planar polychlorinated biphenyls congeners (118, 138, 153 and 180), and of the toxic metals lead and cadmium, and their antagonist selenium and zinc were measured in cord blood from apparently healthy neonates from the region of Prague and Upper Silezia (Katowice). These "background" levels were compared with similar values from neonates in the Netherlands. It was found that the levels of three PCB congeners (138, 153 and 180) were significantly higher in the Prague samples than in the Netherlands; but in the Katowice group they were significantly lower. In Upper Silezia (Katowice) the values of the metals lead and cadmium, and in Prague those of cadmium and selenium were significantly higher than in the Netherlands. The importance of these findings is discussed. It is argued that neurotoxic effects of perinatal exposure can be expected to be more prominent in Central Europe than in Western European countries. A more thorough study is indicated and will be undertaken by a joint Czech/Polish/Dutch/German research group.

Effects of polychlorinated biphenyls (PCBs) and dioxins on growth and development.

Polychlorinated biphenyls (PCBs) and dioxins are potentially toxic compounds which occur widely in the environment. Their effects on the growth and development of infants at the levels currently found in highly industrialised western countries is not well known. This Dutch multicenter study, combining animal and human studies, tries to answer this question. Animal studies showed that PCB 169, given once during pregnancy at a dose of 1.8 g kg-1 bodyweight, has an effect on developmental parameters, dopamine regulation and fertility. Effects on thyroid hormones were also found in animals, probably due to both a competitive binding of PCB metabolites to the thyroxine binding protein and increased glucuronidation. Perhaps to compensate for this, an increased diodase activity in the brain was found. Human studies involved 400 mother-infant pairs, half of them being breast-fed, the other half were fed a formula devoid of PCBs and dioxins. PCB levels were measured in serum and dioxin and PCB levels in breastmilk. Levels were found to be as high as previously found in highly industrialised countries. Growth and development were carefully documented, but no data are as yet available. In pregnant women, a significant negative correlation was found between some dioxin and PCB congeners in milk and plasma thyroid hormones, while newborn infants showed higher thyroid stimulating hormone (TSH) at higher levels of dioxin exposure. In summary, data from this combined multicenter study involving animals and humans increases our insight into the potentially negative effects of PCBs and dioxins on growth and development.

Dioxin and PCB levels in blood and human milk in relation to living areas in The Netherlands.

Dioxins and polychlorinated biphenyls (PCBs) are ubiquitous toxic compounds in the environment. Negative influences of these compounds on the health status of human beings have been described. Especially susceptible might be the fetus, which is exposed in utero, and the newborn breast-fed infant, since both are exposed to relatively high levels of dioxins and PCBs during a critical period of organ growth and development. We investigated PCB levels in 406 maternal plasma samples as well as PCB and dioxin levels in 172 human milk samples with relation to living area of women living for at least five years in the western industrialized part of the Netherlands or the northern more rural part. The western part was further subdivided into one urban and two highly industrialized areas. After correction for covariates, we found significantly higher levels of PCB 118 in maternal plasma as well as significantly higher levels of the dioxin-TEQ and of ten individual dioxin and PCB congener levels in human milk in the western more industrialized areas of the Netherlands compared to the northern more rural part. We did not find significant differences in planar, mono-ortho or di-ortho PCB-TEQ levels in human milk between all different areas. We conclude that significantly higher levels of a number of dioxin and PCB congeners are found in women living in industrialized areas compared to women living in rural areas in the Netherlands.

Effects of dioxins and polychlorinated biphenyls on thyroid hormone status of pregnant women and their infants.

Dioxins [polychlorinated dibenzo-p-dioxins (PCDD), dibenzofurans (PCDF)] and polychlorinated biphenyls (PCB) are potentially hazardous compounds. Animal studies have demonstrated that PCDD, PCDF, and PCB can alter thyroid hormone homeostasis. We investigated thyroid hormone levels in 105 mother-infant pairs. To estimate maternal and infant exposure, four nonplanar PCB congeners were measured in maternal plasma during the last month of pregnancy and in umbilical cord plasma. Seventeen PCDD and PCDF congeners, three planar PCB congeners, and 23 nonplanar PCB congeners were measured in human milk. Higher PCDD, PCDF, and PCB levels in human milk, expressed as toxic equivalents, correlated significantly with lower plasma levels of maternal total triiodothyronine and total thyroxine, and with higher plasma-levels of TSH in the infants in the 2nd wk and 3rd mo after birth. Infants exposed to higher toxic equivalents levels had also lower plasma free thyroxine and total thyroxine levels in the 2nd wk after birth. We conclude that elevated levels of dioxins and PCB can alter the human thyroid hormone status.

[Polychlorobiphenyls in human milk, adipose tissue, plasma and umbilical cord blood; levels and correlates]. / Polychloorbifenylen (PCB's) in moedermelk, vetweefsel, plasma en navelstrengbloed; gehalten en correlaties.

In a longitudinal study involving 17 women, PCB concentrations (PCBs 138, 153 and 180) were determined in cord blood (17 newborns), breast milk (10 women), maternal adipose tissue (8 women), maternal plasma collected during the last trimester of pregnancy (17 women) and maternal plasma collected 10 days post partum (7 women). Significant correlations were found (p less than 0.05) between PCB levels in cord blood, breast milk and adipose tissue and maternal plasma collected before birth, and between breast milk and maternal plasma collected post partum. In 2 vegetarian women the PCB levels in maternal plasma and cord blood were significantly lower than in the other women (p less than 0.05). If in future studies the PCB levels observed prove to be detrimental to child development, these correlations may offer the possibility of identifying a group of newborns at risk for occurrence of developmental defects due to PCB exposure before birth.