Analysis of polychlorinated biphenyls and organochlorine pesticides in pine needles

This paper presents a review of methods for the analysis of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in pine needles. These compounds are lipophilic, they accumulate in the biotic and abiotic part of the environment in which they are persistent, and their use is forbidden or restricted due to harmful effects on human and animal health. Pine needles are convenient for monitoring the levels of organochlorine compounds in the air because they accumulate them in wax with which they are covered. However, the presence of many other compounds makes them complex for analysis. Analytical methods for determining organochlorine compounds in pine needles include sample collection, extraction of compounds with a suitable solvent, extract clean-up from unwanted compounds and qualitative and quantitative analysis. PCBs and OCPs are present in pine needles in traces, and every part of the analytical procedure has to be as efficient and selective as possible.     

Deposition of Organochlorine Pesticides,PCBs (Aroclor 1268), and PBDEs in Selected Plant Species from a Superfund Site at Brunswick,Georgia, USA

Deposition of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) were measured in Loblolly pine needles (Pinus taeda) collected in and around a Linden Chemicals and Plastics (LCP) Superfund Site at Brunswick, Georgia, USA. For the comparison, foliage of eastern red cedar (Juniperus virginiana) was also collected to monitor contaminant levels. This study revealed that concentrations of OCPs, PCBs and PBDEs ranged from 0.75–10, 3.4–15 to 0.05–3, ng/g wet wt, respectively in both plant species. Total OCPs concentrations in pine needles decreased from 10 to 2.3 ng/g; and total PCBs decreased from 28 to 9.3 ng/g between 1997 and 2006. To our knowledge, this is the first report on PBDEs concentrations in pine needles and red cedar foliage samples from the Superfund Site at Brunswick, Georgia, USA.     

Are pine needles bioindicators of air pollution? Comparison of organochlorine compound levels in pine needles and ambient air

Levels of six PCB congeners and seven organochlorine pesticides were investigated and compared in ambient air and in pine needle samples. The applied methods are suitable for the analysis of PCBs and organochlorine pesticides in environmental samples and for their detection in recent intakes. DDE, HCB, lindane, PCB-28, PCB-52, PCB-101, PCB-138 and PCB-153 were found in all pine needle and air samples. The highest median values were found for PCB-28, PCB-101 and gamma-HCH, and the lowest for PCB-180 and DDD. The median value of alpha-HCH/ gamma-HCH ratios was 0.2 in both matrices. DDE/DDT ratios were close to or below 1 in some pine needle and ambient air samples. The results showed a correspondence between air and pine needle pollution; the same compounds were present in the highest or in the lowest levels in both types of matrices. These results suggest that pine needles are passive biomonitors of air pollution.     

Distribution of Persistent Organohalogen Compounds in Pine Needles from Selected Locations in Kentucky and Georgia,USA

Epicuticular wax of pine needles accumulates organic pollutants from the atmosphere, and the pine needle samples have been used for monitoring both local and regional distributions of semivolatile organic air pollutants. One-year-old pine needles collected from residential and industrial locations in western Kentucky and the vicinity of Linden Chemicals and Plastics, a Superfund Site at Brunswick, Georgia, were analyzed for polychlorinated biphenyls (PCBs), major chlorinated pesticides, and polychlorinated naphthalenes (PCNs). Total PCB concentrations in pine needles from Kentucky ranged from 5.2 to 12 ng/g dry weight (dw). These sites were comparatively less polluted than those from the Superfund Site, which had total PCB concentrations in pine needles in the range of 15–34 ng/g dw. Total chlorinated pesticides concentrations in pine needles ranged from 3.5 to 10 ng/g dw from Kentucky. A similar range of concentrations of chlorinated pesticides (7.3–12 ng/g dw) was also found in pine needle samples from the Superfund site. Total PCN concentrations in pine needles ranged from 76 to 150 pg/g dw in Kentucky. At the Superfund Site, total PCN concentrations ranged from 610 pg/g dw to 38,000 pg/g dw. When the toxic equivalencies (TEQs) of PCBs in pine needles were compared, Kentucky was relatively lower (0.03–0.11 pg/g dry wt) than the TEQs at the Superfund Site (0.24–0.48 pg/g dry wt). The TEQs of PCNs from Kentucky (0.004–0.067 pg/g dw) were much lower than the TEQs from locations near the Superfund Site (0.30–19 pg/g dry wt). The results revealed that pine needles are excellent, passive, nondestructive bioindicators for monitoring and evaluating PCBs, chlorinated pesticides, and PCNs.     

Assessment and characterization of polychlorinated biphenyls near a hazardous waste incinerator: analysis of vegetation,snow, and sediments

Samples of spruce needles, snowpack, and sediment were analyzed in the area around the Alberta Special Waste Treatment Centre (ASWTC) near Swan Hills, Canada, in 1997 and 1998, following a major accidental release of polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) in October 1996. The PCB concentrations in spruce needles and snow were mostly elevated to the east of the plant and contained congeners that were not present at upwind or distant sites. Several years of annual vegetation monitoring data indicated that PCB emissions increased prior to the reported accident. Within 3 km of the plant, there was a predominance of higher chlorinated congeners penta-, hexa-, hepta-, and octachlorobiphenyls in white spruce (Picea glauca) needles and snow. Polychlorinated biphenyl congener patterns varied seasonally in spruce needles, likely influenced by temperature effects on the volatilization and of particle-bound and vapor phase PCBs in the forest canopy. The similarity of deposition patterns in snow and needles in 1997 and 1998 suggested the PCBs in the surrounding area were derived by long-term fugitive releases of PCBs rather than an accidental release. In addition, hexachlorobenzene, a combustion by-product of chlorinated organics in waste incinerators, was not measured at elevated concentrations in spruce needles or snow east of the facility and, when detected, was not correlated with PCB concentrations. A radiometrically dated sediment core from nearby Chrystina Lake (AB, Canada) showed a gradual increase in annual PCB flux during the early years of operation of the ASWTC, followed by a higher PCB flux in 1997, indicating that the lake may have been directly contaminated by the accidental release.     

Persistent organic pollutants in muscle and feather of ten avian species from Māzandarān Province of Iran, on the coast of the Caspian Sea

Feather and muscle of 10 avian species (n = 46), were analyzed for polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs). Muscle contained significantly higher PCB and OCP than liver and feather. Mean muscle and feather PCB was 408.5 ± 134.5 and 32 ± 4.5 ng/g wet weight. Highly chlorinated PCBs were found in muscle and liver while feather had PCBs with less chlorination. Gulls had highest levels of both pollutants. Gull feather PCB and OCP were strongly correlated with their levels in the liver and muscle tissues (0.6 < r < 0.9, p < 0.01). Analysis of gull feather can be used as a non-invasive method for monitoring organic pollutants.     

Effects of perinatal exposure to PCBs and dioxins on play behavior in Dutch children at school age

Polychlorinated biphenyls (PCBs) and dioxins are known as neurotoxic compounds that may modulate sex steroid hormones. Steroid hormones play a mediating role in brain development and may influence behaviors that show sex differences, such as childhood play behavior. In this study we evaluated the effects of perinatal exposure to environmental levels of PCBs and dioxins on childhood play behavior and whether the effects showed sex differences. As part of the follow-up to the Dutch PCB/dioxin study at school age, we used the Pre-School Activity Inventory (PSAI) to assess play behavior in the Rotterdam cohort (n = 207). The PSAI assesses masculine or feminine play behavior scored on three subscales: masculine, feminine, and composite. Prenatal exposure to PCBs was defined as the sum of PCB 118, 138, 153, and 180 in maternal and cord plasma and breast milk. For breast milk we measured additional PCBs as well as 17 dioxins. Respondents returned 160 questionnaires (age 7.5 years +/- 0.4). Effects of prenatal exposure to PCBs, measured in maternal and cord plasma, on the masculine and composite scales were different for boys and girls (p <.05). In boys, higher prenatal PCB levels were related with less masculinized play, assessed by the masculine scale (p(maternal) =.042; p(cord) =.001) and composite scale (p(cord) =.011), whereas in girls higher PCB levels were associated with more masculinized play, assessed by the composite scale (p(PCBmilk) =.028). Higher prenatal dioxin levels were associated with more feminized play in boys as well as girls, assessed by the feminine scale (p =.048). These effects suggest prenatal steroid hormone imbalances caused by prenatal exposure to environmental levels of PCBs, dioxins, and other related organochlorine compounds.     

Influence of lake characteristics on the biomagnification of persistent organic pollutants in lake trout food webs

The biomagnification of polychlorinated biphenyls (PCBs) and major organochlorine pesticides (OCPs) was studied using lake trout (Salvelinus namaycush) and other food web organisms collected from 17 lakes in Canada and the northeastern United States between 1998 and 2001. Whole lake trout (n = 357) concentrations of the sum (Sigma) of 57 PCB congeners ranged between 1.67 and 2,890 ng/g wet weight (median 61.5 ng/g wet wt). Slimy sculpin had the highest mean concentrations of SigmaPCB of all forage fish (32-73 ng/g wet wt). Positive relationships between log (lipid wt) concentrations of PCB congener 153, PCB congener 52, p,p'-dichlorodiphenyldichloroethylene, hexachlorobenzene, cis-chlordane, trans-nonachlor, or dieldrin and trophic level (determined using stable nitrogen isotope ratios) were found for most of the 17 food webs, indicating biomagnification of these PCBs and OCPs. The p,p'-dichlorodiphenyldichloroethylene had the highest trophic magnification factors (TMFs) of the 14 individual compounds studied, averaging 4.0 +/- 1.8 across the 17 lakes, followed by trans-nonachlor (3.6 +/- 1.5) and PCB congener 153 (3.4 +/- 1.2). Average TMFs for 14 individual PCBs or OCPs were significantly correlated with log octanol-water partition coefficient, implying that the rate of accumulation along the food web is dependent on hydrophobicity and recalcitrance. Significant correlations (p < 0.05) were found between TMFs of SigmaPCBs, hexachlorobenzene, alpha-hexachlorocyclohexane, and lindane and lake area, latitude, and longitude, but not for 11 other PCBs or OCPs. Overall, the results of the present study show that biomagnification of PCBs and most OCPs, as measured by TMFs, is only weakly influenced by such factors as latitude and longitude. Exceptions are hexachlorocyclohexane isomers and hexachlorobenzene, which had generally greater TMFs in northern lakes, possibly due to lower rates of elimination and biotransformation in the food web.     

Human and environmental biomonitoring of polychlorinated biphenyls and hexachlorobenzene in Saxony, Germany based on the German Environmental Specimen Bank

The objective of the present study was to investigate the principle relationships between concentrations in human and environmental matrices of polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB) in short distance comparable areas within Saxony, Germany by employing the data of the German Environmental Specimen Banking (ESB). Examples supporting this idea were presented by selecting data on blood plasma collected from students in University of Halle and pine shoots, egg matter of city pigeons, earthworm, and roe deer liver. Similar pattern for PCB 138 and PCB 180 was found for the human plasma and pine shoots samples during investigated years and the human data followed the corresponding environmental levels with some delay of approximately two years. However, PCB 153 that was the prevailing congener did not manifest this relationship. In addition, the correlation of the ratios of concentrations (human/environmental concentration) to some physicochemical constants such as molecular weight (MW), octanol-water partition coefficient (logK(ow)), Henry's law constant (K(H)), and sorption partition coefficient (logK(oc)) of HCB, PCB 138, PCB 153, and PCB 180 were studied. The resulted negative slopes with all constants in case of blood plasma/city pigeons egg matter pairs suggested that the accumulation of lipophilic compounds is more pronounced in pigeon eggs than in human blood.     

Pilot study on the exposure of the German general population to non-dioxin-like and dioxin-like PCBs

In the past, polychlorinated biphenyls (PCBs) have been widely used and were distributed in the environment. Due to their high persistence and bioaccumulative potential, they can still be detected in the blood of the general population, despite their ban more than 20 years ago. Among the various congeners, the presence of dioxin-like PCBs in blood raises the highest environmental concerns due to their critical toxicological properties. We determined the plasma concentrations of 6 non-dioxin-like and 12 dioxin-like PCBs as well as the organochlorine pesticides HCB and p,p'-DDE (p,p'-dichlorodiphenyldichloroethylene) in a group of 105 non-smokers out of the German general population by GC/MS as an estimate of the background burden to these compounds. The organochlorine compounds were extracted from plasma with n-hexane, cleaned up on a silica gel column and finally quantified using GC/MS and (13)C(12)-labelled internal standards. The limit of detection for all congeners was determined to be 0.01 μg/Lplasma. Age had a strong influence on the plasma levels of HCB (hexachlorobenzene), p,p'-DDE and all higher chlorinated PCB congeners, while no gender difference was observed. Among the dioxin-like PCBs, PCB 118, PCB 156 and PCB 167 were detectable in 74-98% of all samples. Highly significant correlations between several PCB-congeners were observed. Our results provide for the first time volume-based data on the extent of the age-related background burden to dioxin-like PCBs in Germany.     

Evidence of PCDD/Fs and PCBs Contamination in Trees Grown in Forests Far from Their Production and Contamination-Free Areas

Polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) in trees grown in pathless forests were analyzed to investigate their dispersal patterns in the atmosphere. The pg/g levels of 23 PCCD, 22 PCDF, and 54 PCB congeners were identified. The total amount of PCDDs in the red pine tree sample (95.8 pg/g) was approximately 7 times that in the beech tree sample (13.2 pg/g). The total amount of PCDFs in the red pine tree sample (71.1 pg/g) was also approximately 7 times that in the beech tree sample (11.1 pg/g). The total amounts of PCBs in the red pine tree and beech tree samples were 1,380 and 1,150 pg/g, respectively. The (Cl₁–Cl₃)-PCBs comprised 63.1 % and 67.6 % of total PCBs in the red pine and in the beech, respectively. The results of the present study indicate that PCDD/Fs and PCBs are transferred over long distances in the atmosphere and accumulated in the contamination-free areas.     

Distribution of Chlorinated Organic Pollutants in a Wide Variety of Soils from Europe and Asia: A Multivariate Statistical Approach

Principal component analysis was used to interpret the levels of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) previously determined in a wide variety of soils from Europe and Asia to (1) examine the interdependencies among them and chosen soil charaeteristics and (2) reveal PCB– and OCP–soil patterns throughout Europe and Asia. Loading values suggested correlations between the levels of certain compounds and soil characteristics, revealing the underlying structure of analyzed data; humus content, pH, and density correlated with the contents of p,p’-DDT, β-hexachlorocyclohexane (HCH) and γ-HCH, and clay content correlated with the concentrations of α-HCH and PCB 28. Component scores reflected relatively low concentrations of six “marker” PCBs in most of the soils, pointing out the outliers in the proximity of the local PCB sources. PCB loads in the 1990s and early 2000s were lower than the ones in 1980 and 1956, and they coincided with the soil levels in 1944. PCBs 138, 153, and 180 had the greatest influence of the six investigated congeners on soil-pattern differences. In relation to the OCP soil loads, the score plot revealed regions with recent and/or enhanced application of DDT and HCH.     

Tissue Distribution of Polychlorinated Biphenyls and Organochlorine Pesticides and Potential Toxicity to Alaskan Northern Fur Seals Assessed Using PCBs Congener Specific Mode of Action Schemes

The fur seal (Callorhinus ursinus) population has decreased in their primary breeding grounds in the Bering Sea; contamination is among suspected causes. Our goal was to better understand the extent of contamination of seal tissues with certain organochlorine compounds by measuring the concentrations of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in fur seal tissues from St. Paul Island, to gain a better perspective of tissue congener distribution and to evaluate the observed PCB levels against toxicologically significant levels for modes of action. Concentrations of 145 PCB congeners (∑₁₄₅PCBs) and 12 OCPs were measured with gas chromatography–ion trap mass spectrometry in 8 different tissues of 10 male northern fur seals. The mean concentrations of ∑OCPs [in ng/g lipid weight (lw)] were 1180 in blubber, 985 in the heart, 1007 in the liver, 817 in the kidney, 941 in muscle, 660 in reproductive tissues, 204 in the brain, and 322 in the lung. The mean concentrations of ∑₁₄₅PCBs (in ng/g lw) were 823 in blubber, 777 in the liver, 732 in the heart, 646 in reproductive tissues, 638 in muscle, 587 in the kidney, 128 in the lung, and 74.3 in brain tissues. Concentrations of PCBs affecting the aryl hydrocarbon receptor expressed as total PCB toxic equivalents (∑PCB-TEQs) ranged from 0.3 to 545 pg/g lw for the various tissues. The major contributors to ∑PCB-TEQs are CB-118 in muscle, brain, lung, kidney, and liver, CB-126 in blubber, and CB-118 and CB-126 equally in the heart and reproductive tissues. Concentrations of PCBs affecting Ca²⁺ homeostatsis expressed as the neurotoxic equivalent (NEQ) showed ∑PCB-NEQs ranged from 17.7 to 215 ng/g lw in all tissues. Although no composite measure of perturbation of thyroid function is available, sufficient amounts of congeners with high binding to the thyroxine transport system were present to warrant consideration of this mode of action in future studies. Analyses of 145 PCBs and mode of action evaluation suggest that PCB contamination could potentially exert an effect on the Alaskan northern fur seal population although the PCB concentrations have been decreasing in the fur seals over the last decade.     

Polychlorinated biphenyls and thyroid hormone serum concentrations among people living in a highly polluted area: a cross-sectional population-based study

Background

Polychlorinated biphenyls (PCBs) may interact with several thyroid functions. Severe environmental pollution by PCBs has been observed in Brescia, Italy, due to the presence of a factory that produced these compounds until 1984.

Objectives

We aimed to investigate the correlation between serum levels of total PCBs and PCB 153 and thyroid hormone serum levels in adults in a cross-sectional population-based study.

Methods

A total of 527 subjects were enrolled; they were face-to-face interviewed about their history of thyroid disease and provided a blood sample under fasting conditions. The serum levels of free and total triiodothyronine (FT3 and TT3), thyroxine (FT4 and TT4) and thyroid-stimulating hormone (TSH), anti-thyroperoxidase (anti-TPO) and anti-thyroglobulin (anti-TGA), and lipid-adjusted total PCBs and PCB 153 were determined.

Results

There was no statistically significant difference in total PCB and PCB 153 concentrations in subjects with and without thyroid disease. Inverse, weak, statistically significant correlations were found between total PCBs and FT3 (Spearman's r=−0.09) and between total PCBs and PCB 153 and TSH (Spearman's r=−0.16 and −0.12, respectively). However, multiple regression analysis with FT3 and TSH serum levels as dependent variables and total PCBs and PCB 153 serum levels as predictors, including age, gender and BMI, showed a positive, rather than negative, association of PCBs and PCB 153 with FT3 and no association with TSH.

Conclusions

This study does not support the hypothesis that relatively high PCB environmental exposure can determine substantial alterations in thyroid function among adult people.     

Polychlorinated biphenyl contamination of nursing mothers' milk in Michigan.

The problem of environmental contamination by toxic substances and human exposure to these substances has attracted increased attention in recent years. Particular concern has centered on polychlorinated biphenyls (PCBs), which have become widespread environmental pollutants as well as contaminants of the human population. This paper reports data from a study of PCB contamination of nursing mothers' breast milk in Michigan. During 1977 and 1978, breast milk samples of 1,057 nursing mothers residing in Michigan were tested for PCB residues. All of the 1,057 samples collected from 68 of the state's 83 counties contained PCB residues ranging from trace amounts to 5,100 parts per million (fat weight basis). The mean level was 1,496 parts per million (ppm), with 49.5 per cent of the samples having PCB levels of 1-2 ppm, 17.4 per cent had 2-3 ppm, and 6.14 per cent had more than 3 ppm. There was no consistent trend in the level of PCB contamination over the 24 months of monitoring. The mean PCB level for the eighth quarter of monitoring was slightly higher than for the first quarter. The public health significance of PCB contamination in human populations and its effects on breast-fed for eight months by a woman with the average PCB level in this sample would have an estimated body burden of approximately 0.89 ppm of PCBs. The implications of PCB contamination of human milk with regard to current breast-feeding practices are discussed and several precautionary measures are recommended.     

Persistent Organochlorine Contaminant Residues in Tissues of Hedgehogs from Turkey

The residues of persistent organochlorinated pollutants (POPs), namely polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) (HCHs, CHLs, HCCPs, DDTs, and dicofol congeners) were investigated in the hair and muscle of road-killed Erinaceus roumanicus and E. concolor in Turkey. Mean residue levels were as follows: in hair, PCBs?=?7.43?±?4.88 ng/g and OCPs?=?9.21?±?1.27 ng/g; in muscle, PCBs?=?30.73?±?2.51 ng/g and OCPs?=?145.04?±?16.59 ng/g. There was no significant difference between species and sex, while there was significant difference between habitats and regions in terms of either total PCB and OCP levels, or POP levels (p?<?0.05). Age was a determinative factor for the bio-accumulation of POPs. The contaminant levels were high in the species, sample areas, and habitats. The data also showed that tissues of hedgehogs are suitable for monitoring and evaluating the bioaccumulation of POP levels in Turkey.     

Impact of polychlorinated biphenyls contamination on estrogenic activity in human male serum

Polychlorinated biphenyls (PCBs) are thought to cause numerous adverse health effects, but their impact on estrogen signaling is still not fully understood. In the present study, we used the ER-CALUX bioassay to determine estrogenic/antiestrogenic activities of the prevalent PCB congeners and PCB mixtures isolated from human male serum. The samples were collected from residents of an area with an extensive environmental contamination from a former PCB production site as well as from a neighboring background region in eastern Slovakia. We found that the lower-chlorinated PCBs were estrogenic, whereas the prevalent higher-chlorinated PCB congeners 138, 153, 170, 180, 187, 194, 199, and 203, as well as major PCB metabolites, behaved as antiestrogens. Coplanar PCBs had no direct effect on estrogen receptor (ER) activation in this in vitro model. In human male serum samples, high levels of PCBs were associated with a decreased ER-mediated activity and an increased dioxin-like activity, as determined by the DR-CALUX assay. 17beta-Estradiol (E2) was responsible for a major part of estrogenic activity identified in total serum extracts. Significant negative correlations were found between dioxin-like activity, as well as mRNA levels of cytochromes P450 1A1 and 1B1 in lymphocytes, and total estrogenic activity. For sample fractions containing only persistent organic pollutants (POPs), the increased frequency of antiestrogenic samples was associated with a higher sum of PCBs. This suggests that the prevalent non-dioxin-like PCBs were responsible for the weak antiestrogenic activity of some POPs fractions. Our data also suggest that it might be important to pay attention to direct effects of PCBs on steroid hormone levels in heavily exposed subjects.     

Assessing the cancer risk from environmental PCBs.

A new approach to assessing the cancer risk from environmental polychlorinated biphenyls (PCBs) considers both toxicity and environmental processes to make distinctions among environmental mixtures. New toxicity information from a 1996 cancer study of four commercial mixtures strengthens the case that all PCB mixtures can cause cancer, although different mixtures have different potencies. Environmental processes alter PCB mixtures through partitioning, chemical transformation, and preferential bioaccumulation; these processes can increase or decrease toxicity considerably. Bioaccumulated PCBs are of greatest concern because they appear to be more toxic than commercial PCBs and more persistent in the body. The new approach uses toxicity studies of commercial mixtures to develop a range of cancer potency estimates and then considers the effect of environmental processes to choose appropriate values for representative classes of environmental mixtures. Guidance is given for assessing risks from different exposure pathways, less-than-lifetime and early-life exposures, and mixtures containing dioxinlike compounds.     

PCBs exert an estrogenic effect through repression of the Wnt7a signaling pathway in the female reproductive tract

Polychlorinated biphenyls (PCBs) have been proposed to have a weak estrogenic activity and therefore pose a risk as potential environmental endocrine disruptors to the perinatal development of the female reproductive tract. Perinatal exposure to high concentrations of the potent synthetic estrogen diethylstilbestrol (DES) induces abnormal development of the female reproductive tract via a mechanism that acts through the down-regulation of Wnt7a (wingless-type MMTV integration site family, member 7A). To test the hypothesis that PCBs act as weak estrogens, we injected neonatal mice with a commercial PCB mixture (Aroclor 1254) or with low levels of DES and measured effects of exposure on Wnt7a expression and uterine morphology. We report here that neonatal PCB or low-level DES exposure resulted in the down-regulation of Wnt7a expression. In addition, both PCB and low-level DES exposure induced changes in the uterine myometrium and gland formation. These data reveal that weak estrogens such as the PCBs act through a Wnt7a-dependent pathway and suggest that Wnt7a regulation is a sensitive biomarker for testing weak estrogenic candidate compounds. The morphologic changes that were elicited by PCBs and DES were different immediately after exposure, suggesting that Wnt7a-independent pathways are also activated by one or both of these compounds. Although Wnt7a down-regulation is transient after estrogenic exposure, subsequent morphologic changes became more pronounced during postnatal and adult life, suggesting that the female reproductive tract is permanently reprogrammed after exposure even to weak estrogenic compounds. In addition, Wnt7a heterozygous mice were more sensitive to PCB exposure, revealing an important genetic predisposition to risks of environmental endocrine disruptors.     

Exposure and effects of persistent organic pollutants in European shag (Phalacrocorax aristotelis) hatchlings from the coast of Norway

Although the coast of Norway is relatively clean regarding contaminants compared to areas of Europe with higher density of both people and industry, levels of persistent organic pollutants (POPs) exist in the marine ecosystem that may cause chronic exposure effects in wildlife. In this study, polychlorinated biphenyls (PCBs), some organochlorinated pesticides (OCPs), polybrominated diphenyl ethers (PBDEs), and hexabromocyclododecane (HBCD) were analyzed in yolk sac of European shag (Phalacrocorax aristotelis) hatchlings from an island situated on the coast of Mid-Norway. In addition, levels of retinol (vitamin A), retinyl palmitate, and alpha-tocopherol (vitamin E) were measured in plasma and liver. The shag hatchlings seemed to be relatively highly contaminated by PBDEs and HBCD on a European scale. A negative relationship between PBDE-28 and liver tocopherol levels was revealed, and plasma retinol levels correlated negatively to levels of several PCB congeners, the summed PCB concentrations (sigmaPCBs), and some OCPs. More studies should be done to reveal the effects of POPs, and especially PBDEs, on vitamin status in wild birds.