Concentrations Of Polybrominated Biphenyls Research Articles

Polybrominated biphenyl exposure and thyroid function tests in electronic waste dismantling and general population of Chinese adults

This study aimed to determine the concentration of 35 PBB (polybrominated biphenyls) congeners in the human serum of residents from an electronic waste (e-waste) dismantling area compared to a control area in China. Additionally, four thyroid hormones, namely FT3, FT4, TSH, and TRH, were also analyzed. The findings revealed that the total PBB concentrations (sum of the 35 PBB congeners) ranged from 47.1 to 1360 ng/g lipid in the e-waste area and 105–1980 ng/g lipid in the control area. BB-1 and BB-10 were the dominant congeners in both study areas, followed by BB-209. Compared to the e-waste dismantling area, the control area samples had a significantly higher concentration of less-brominated (Br1–3) PBBs, including the concentrations of less-brominated congeners such as BB-1, BB-4, BB-9, and BB-10, which were significantly higher than those in the e-waste dismantling area. Conversely, more-brominated hexabromobiphenyl congeners BB- 153, BB-154 and BB-155 were found in samples from the e-waste dismantling area at significantly higher concentrations than in the control area. E-waste dismantling areas have released historically produced commercial PBB products, but equally not negligible is the exposure of the general population to newly produced PBB congeners. PBB concentrations in the e-waste dismantling area samples decreased with increasing age, while they increased with increasing age in the control area samples. Furthermore, stepwise multiple regression analysis showed a significant association between BB-103 concentrations and thyroid hormone levels. In addition, BB- 103 has the potential to interfere with the binding of T3 and thyroid hormone receptors (TR). Given these findings, the research on human exposure of PBB and the relationships between the PBB and thyroid hormones should be studied further.

Previously identified and unidentified polybrominated biphenyl congeners in serum from people living in an electronic waste dismantling area in China

The effects of polybrominated biphenyls (PBBs) on human health have previously attracted much attention, but recent studies of PBBs have been focused on BB-153 and a few other congeners. PBB concentrations in serum samples from residents of an area containing an electronic waste dismantling site were determined in this study. The total PBB concentrations (i.e., the sums of the concentrations of the 35 PBB congeners) were 229–1360 ng/g lipid. The BB-153 concentrations were markedly higher in the samples from people living in the electronic waste dismantling area than in samples from people living in a nearby control area. BB-153 was found in all of the samples from the study exposure area but the concentrations were relatively low (0.07–4.70 ng/g lipid). High BB-1 concentrations were found for the first time in serum from people living in both the electronic waste dismantling and control areas. The BB-1 concentrations were 211–1280 ng/g lipid. The retention times of the 35 PBB standards and PCBs (polychlorinated biphenyls) with similar structures were used to predict the retention times of unidentified PBB congeners to allow the PBB distributions in the serum samples to be identified. A total of 26 previously unidentified PBB congeners were identified in the human serum samples. BB-5, BB-35, BB-79, and BB-109 were found in >50% of the samples. The PBB patterns in the serum samples were different from the patterns previously found in serum after a PBB contamination incident in 1973, so the health risks currently posed by PBBs are worth studying.

Dioxin-like polybrominated biphenyls (PBBs) and ortho-substituted PBBs in edible cod (Gadus morhua) liver oils and canned cod livers

This study investigates the occurrence of polybrominated biphenyls (PBBs), a legacy flame retardant, in fishery products such as medicinal grade cod liver oils and canned liver products, sourced from the North Atlantic during 1972–2017. It also assesses the dietary and supplementary (the oils were commonly administered as dietary supplements to children and youth) intake of PBBs from these products. Summed ortho-PBB concentrations ranged from 770 to 1400 pg g−1 fat in the oils and from 99 to 240 pg g−1 whole weight in canned livers, with PBB-49, 52, 101 and 153 accounting for most of these levels. Among the more toxic non-ortho-PBBs, PBB-126 and PBB-169 were not detected, but PBB-77 concentrations ranged from 0.6 to 5.78 pg g−1 fat in the oils and 0.06–0.126 pg g−1 whole weight in canned livers. During 1972–1993, PBB contamination levels were similar for cod liver oils from the Baltic Sea and other North Atlantic regions, but over the timescale of the study, Baltic Sea products appear to show a decline in PBB concentrations. As PBB-77 was the only dioxin-like PBB detected in the samples, the corresponding supplementary (oils, 1972–2001) and dietary (cod liver from 2017) intakes were very low, at < 0.001 pg TEQ kg−1 bm d−1 (or < 0.01 pg TEQ kg−1 bm d−1 upper bound) for the sum of all the measured dioxin-like PBBs –four to six orders of magnitude lower than that arising from other dioxin-like contaminants that were shown to occur in these products, from earlier studies.

Levels, distributions, and ecological risk assessments of polybrominated diphenyl ethers and alternative flame retardants in river sediments from Vaal River, South Africa.

Sediments are known to be the ultimate sink for most pollutants in the aquatic environment. In this study, the concentrations of both legacy polybrominated diphenyl ethers (PBDEs) and alternative halogenated flame retardants (AHFRs) were measured in sediments samples from the Vaal River catchment. The concentrations of Σ7BDE-congeners ranged from 20 to 78ngg-1 dry weight (dw) with BDE-209, -99, and -153 as the dominant congeners. The concentrations observed ranged from 9.4-56, 4-32, and 1-10.6ngg-1 for BDE-209, -99, and -153, respectively. The concentrations of AHFRs, mainly contributed by decabromodiphenyl ethane (DBDPE) at approximately 95% of total AHFRs, ranged from 64 to 359ngg-1 dw while the concentration of polybrominated biphenyls (PBBs), mainly PBB-209, ranged from 3.3-7.1ngg-1 dw. The ratios of AHFRs to PBDEs observed in this study were 0.76, 1.17, and 7.3 for 2-ethyl-1-hexyl-2,3,4,5-tetrabromobenzoate and bis-(2-ethylhexyl)-tetrabromophthalate (EH-TBB & BEH-TEBP)/penta-BDE; 1,2-bis-(2,4,6-tribromophenoxy) ethane (BTBPE)/octa-BDE; and DBDPE/BDE209, respectively. These results indicate dominance of some AHFRs compared to PBDEs. Our results indicates that BDE-99 poses high risk (RQ > 1) while BDE-209 posed medium risk (0.1 < RQ < 1). Though the concentration of DBDPE was several orders of magnitude higher than BDE209, its ecological risk was found to be negligible (RQ < 0.01). Thus, more attention is required to regulate the input (especially the e-waste recycling sites) of brominated flame retardants into the environment.

Serum Polybrominated Biphenyls (PBBs) and Polychlorinated Biphenyls (PCBs) and Thyroid Function among Michigan Adults Several Decades after the 1973-1974 PBB Contamination of Livestock Feed.

Background:In 1973–1974, Michigan residents were exposed to polybrominated biphenyls (PBBs) through an accidental contamination of the food supply. Residents were enrolled in a registry assembled after the incident, and they and their children participated in follow-up studies to assess subsequent health outcomes.Objectives:We evaluated associations between serum PBBs and polychlorinated biphenyls (PCBs) and markers of thyroid function among Michigan adults.Methods:Serum concentrations of four PBB and four PCB congeners were measured at least once in 753 adults, including 79 women who participated in a 2004–2006 study and 683 women and men with follow-up during 2012–2015. Participants completed questionnaires on health conditions (including physician-diagnosed thyroid disease), behaviors, and demographics. Thyroid hormones were measured in a subset without thyroid disease (). In multivariable linear regression models, PBB and PCB congener concentrations, on both the volume (nanogram/milliliter) and lipid (nanogram/gram lipid) basis, were assessed in relation to thyroid hormones. Logistic regression models were used to estimate associations between serum PBBs and PCBs and thyroid disease.Results:Thyroid disease was common (18% overall; 25% among women). Among women, all odds ratios (ORs) for PBB-153 and thyroid disease were positive for quintiles above the reference level, but estimates were imprecise and were without a monotonic increase. For an interquartile range (IQR) increase in PBB-153 (), the ; (95% CI: 0.83, 1.52) (); for hypothyroidism, (95% CI: 0.86, 2.13) (). There were 21 cases of thyroid disease in men [ (95% CI: 0.33); 1.44 for an IQR increase () in serum PBB-153]. PCB congeners were statistically significantly associated with greater total and free thyroxine and total triiodothyronine among women and with total and free triiodothyronine among men in lipid-standardized models.Conclusions:We found some evidence to support associations of PBBs and PCBs with thyroid disease and thyroid hormone levels. https://doi.org/10.1289/EHP1302

Effect of Smoking and Caffeine Consumption on Polybrominated Diphenyl Ethers (PBDE) and Polybrominated Biphenyls (PBB)

Effect of smoking and caffeine consumption (CC) on the levels of polybrominated diphenyl ethers (PBDE) and polybrominated biphenyls (PBB) has not been adequately studied. Data from 2003–2004 National Health and Nutrition Examination Survey (n = 1013) to simultaneously evaluate the effect of smoking and CC on levels of serum 2,2',4,4'-tetrabromodiphenyl ether (PBDE-47), 2,2',4,4',5-pentabromodiphenyl ether (PBDE-99), 2,2',4,4',6-pentabromodiphenyl ether (PBDE-100), 2,2',4,4',5,5'-hexabromodiphenyl ether (PBDE-153), and their sum and 2,2',4,4',5,5'-hexabromobiphenyl (PBB-153) were used. Regression models were fitted with logs of PBDE and PBB as dependent variables and age, age2, gender, body mass index (BMI), race/ethnicity, smoking status, fish/shellfish consumption status during the last 30 d, and CC as independent variables. For lipid-adjusted models, age was negatively associated while age2 was positively associated with almost all PBDE models. The reverse was the case for PBB-153. Body mass index was found to be negatively associated with PBDE-153 and PBB-153. Levels of all whole weight PBDE increased with levels of total lipid. Smoking was not markedly associated with concentrations of either PBDE or PBB. Males displayed significantly higher levels of PBDE-153 and ΣPBDE. For the whole weight PBDE congeners 47, 99, and 100 and PBB-153, non-Hispanic black (NHB) males showed significantly higher levels than NHB females.

Dietary exposure to brominated flame retardants and abnormal Pap test results.

This study examined a possible association of dietary exposure to polybrominated biphenyls (PBBs), a brominated flame retardant, and self-reported abnormal Pap test results and cervical dysplasia as a precursor to cervical cancer. Women in Michigan who ingested contaminated poultry, beef, and dairy products in the early 1970s were enrolled in a population-based cohort study in Michigan. Serum PBB and serum polychlorinated biphenyl (PCB) concentrations were measured. Reproductive history and health information, including Pap test results, were self-reported by participants. Of the women, 23% (223 of 956) reported an abnormal Pap test. In unadjusted analyses, self-reporting an abnormal Pap test was associated with younger age, current smoking (hazard ratio [HR] 1.61, 95% confidence interval [CI] 1.19-2.17), and longer duration of lifetime use of oral contraceptives (≥10 years; HR 1.92, 95% CI 1.21-3.06). When adjusting for PCB exposure, age at the interview, and smoking history, there was a slightly elevated risk of self-reporting an abnormal Pap test among the highly exposed women compared to women with nondetectable PBB concentrations (PBB≥13 μg/L, HR 1.23, 95% CI 0.74-2.06); however, the CI was imprecise. When breastfeeding duration after the initial PBB measurement was taken into account, there was a reduced risk of self-reporting an abnormal Pap test among the highly exposed women who breastfed for ≥12 months (HR 0.41, 95% CI 0.06-3.03; referent group: women with nondetectable PBB concentrations who did not breastfeed). It remains important to evaluate the potential reproductive health consequences of this class of chemicals as well as other potential predictors of abnormal Pap tests.

Incidence of thyroid disease following exposure to polybrominated biphenyls and polychlorinated biphenyls, Michigan, 1974–2006

Thyroid hormones, which influence body metabolism and development, could be affected by persistent organic pollutants. We sought to examine the relationship between polybrominated biphenyls (PBBs) and polychlorinated biphenyls (PCBs) and thyroid disease. We employed incidence density sampling to perform a nested case control analysis of the Michigan Long-Term PBB Cohort. Cohort members (n=3333) were exposed to PBBs through contaminated cattle feed in 1973–1974 and to PCBs through daily life. Those with detectable serum PBB and PCB concentrations at enrollment were categorized into tertiles of PBB and PCB exposure. Case-patients were cohort members answering “Yes” to “Has a healthcare provider ever told you that you had a thyroid problem?” during follow-up interviews; control-patients were cohort members answering “No”. We used odds ratios (OR) with 95% confidence intervals (CI) to compare odds of thyroid disease by PBB and PCB exposure and by various risk factors. Total cumulative thyroid disease incidence after 33years was 13.9% among women and 2.6% among men. After adjusting for body mass index, we found no statistically significant differences in odds of any type of thyroid disease among women or men with elevated PBB or PCB exposure. Compared to control-patients, women with thyroid disease had increased odds of being overweight/obese (OR=2.82, 95% CI: 1.94–4.11) and developing infertility (OR=1.71, 95% CI: 1.08–2.69), diabetes (OR=1.61, 95% CI: 1.04–2.51), or arthritis (OR=1.71, 95% CI: 1.18–2.50) during follow-up. Additional research should explore potential associations between PBBs/PCBs and thyroid disease among children exposed in utero.

Preparation of a molecularly imprinted polymer using TMB as a dummy template and its application as SPE sorbent for determination of six PBBs in and fish samples.

A novel molecularly imprinted polymer (MIP) based on a silica-gel surface for the separation and concentration of polybrominated biphenyls (PBBs) was prepared using 3,3',5,5'-tetramethylbenzidine (TMB) as a dummy template by a surface molecular imprinting technique in combination with a sol-gel process. The results obtained from a series of adsorption experiments proved that the prepared sorbent had a good adsorption capacity and a fast mass transfer rate to TMB. Meanwhile, a method was developed for the determination of six PBBs using TMB-MIP as a solid-phase extraction (SPE) enrichment sorbent coupled to GC-ECD. Under the optimum experimental conditions, the linear range of the calibration curve was 0.01-5.0 μg L-1 (r2 > 0.99), and LODs for each analyte were between 2.0 ng L-1 and 8.0 ng L-1. Relative standard deviations (RSD) for nine replicate detections of 1.0 μg L-1 of each analyte ranged from 4.30% to 7.89%. The proposed method was applied to the determination of six PBBs in spiked water and fish samples with recoveries ranging from 61.48% to 114.06%.

Determination of polybrominated biphenyls in Tasmanian devils (Sarcophilus harrisii) by gas chromatography coupled to electron capture negative ion tandem mass spectrometry or electron ionization high‐resolution mass spectrometry

Two gas chromatography/mass spectrometry (GC/MS) methods for the determination of polybrominated biphenyls (PBBs) by isotope dilution analysis (IDA) using (13)C(12)-PBB 153 in the presence of polybrominated diphenyl ethers (PBDEs) were compared. Recovery of (13)C(12)-PBB 153 which was added to the extracted lipids before sample purification was commenced ranged from 88-117% (mean value 98.2 +/- 8.9%). Nevertheless, IDA analysis of PBBs using (13)C(12)-labelled congeners is limited by the potential co-elution of PBBs with polybrominated diphenyl ethers (PBDEs). The pair PBB 153 and BDE 154 was inspected since M(+) and [M-2Br](+) ions of (13)C(12)-PBB 153 and BDE 154 were only separated by 4 u. Gas chromatography/electron ionization high-resolution mass spectrometry with selected ion monitoring (GC/EI-HRMS-SIM) was suitable when m/z 475.7449 and m/z 477.7429 were used for (13)C(12)-PBB 153 because they are below the monoisotopic peak of the [M-2Br](+) fragment ion of hexaBDEs at m/z 479.7. Gas chromatography/electron capture negative ion tandem mass spectrometry selected reaction monitoring (GC/ECNI-MS/MS-SRM) measurements could be applied because (13)C(12)-PBB 153 and BDE 154 were separated by GC on a 25-m Factor Four CP-Sil 8MS column.Comparative measurements with GC/EI-HRMS-SIM and GC/ECNI-MSMS-SRM were carried out with samples of Tasmanian devils from Tasmania (Australia), an endangered species due to a virus epidemy which has already proved fatal for half of the population. Both techniques verified concentrations of PBB 153 in the range 0.3-11 ng/g lipids with excellent agreement of the levels in all but two samples. The PBB residue pattern demonstrated that PBB pollution originated from the previous discharge with technical hexabromobiphenyl which is dominated by PBB 153. Other congeners such as PBB 132 and PBB 138 were detected in the Tasmanian devils but the proportions relative to PBB 153 were lower than in the technical product. Samples of healthy and affected Tasmanian devils showed no significant difference in the PBB pollution level. The PBB concentrations in the Tasmanian devils were significantly below those causing toxic effects. On the other hand, PBB concentrations were one level or even higher than PBDEs.

Simultaneous preconcentration of a wide variety of organic pollutants in water samples: Comparison of stir bar sorptive extraction and membrane-assisted solvent extraction

Stir bar soptive extraction (SBSE) coupled to thermal desorption-gas chromatography–mass spectrometry (TD-GC–MS) and membrane-assisted solvent extraction (MASE) coupled to large volume injection-programmed temperature vaporisation-GC–MS (LVI-PTV-GC–MS) were optimised for the simultaneous determination of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), phthalate esters (PEs), nonylphenols (NPs), polybrominated biphenyls (PBBs) and polybrominated diphenyl ethers (PBDEs) in water samples. In the case of SBSE-TD, variables affecting the extraction (extraction time, addition of sodium chloride or methanol and sample volume) and desorption (cryofocusing temperature, desorption time and temperature, vent pressure and desorption flow) were fitted for the simultaneous determination. The extraction solvent nature ( n-hexane, cyclohexane, n-heptane, ethyl acetate, toluene, dichloromethane or cyclohexane:ethyl acetate mixtures), as well as the addition of methanol (0–30%) and sodium chloride (0–20%), the extraction temperature (30–60 °C), shaking speed (250–750 rpm) and extraction time (5–150 min) were studied for the simultaneous membrane-assisted preconcentration. Finally, PTV-LVI variables such as injection volume (100–600 μL), injection speed (10–40 μL s −1), vent pressure (0–12.7 psi), vent time (0.05–0.8 min), vent flow (30–80 mL min −1), cryofocusing temperature (20–70 °C), split flow (20–100 mL min −1) and split time (1–5 min) were optimised. The optimisation was carried out by means of experimental design approaches in most of the cases. Precision (∼3–19% for both SBSE-TD and MASE-LVI-PTV), accuracy (∼80–120% for both SBSE-TD and MASE-LVI-PTV), limits of detection (LoDs) (0.1–222 ng L −1 for MASE-LVI-PTV and 0.03–20.4 ng L −1 for SBSE-TD in dependence of substance) and linearity (from 25 ng L −1 up to at least 500 ng L −1 for both procedures) were established for both procedures. Finally, the developed methods were applied to the determination of the free concentrations of PAHs, PCBs, PEs, NPs, PBBs and PBDEs in natural water samples (estuarine water and sea water) from the Bilbao estuary (Northern Spain) and comparable results were obtained with both procedures.

Spatial distribution of polybrominated diphenyl ethers and polybrominated biphenyls in lake trout from the Laurentian Great Lakes

Concentrations of two types of brominated flame-retardants (BFRs); polybrominated diphenyl ethers (PBDEs) and polybrominated biphenyls (PBBs) were determined in a single age class of lake trout ( Salvelinus namaycush) collected from the Laurentian Great Lakes in 1997. Mean concentrations of total PBDE were highest in samples from Lake Ontario at 95±22 ng/ g wet weight (ww) or 434±100 ng/ g lipid weight (lw) while the lowest concentrations were observed in Lake Erie lake trout (27±8.6 ng/ g ww , 117±37 ng/ g lw ) . In all samples, the predominant PBDE congeners were 2,2 ′,4,4 ′-tetrabromodiphenyl ether (BDE-47), 2,2 ′,4,4 ′,5-pentabromodiphenyl ether (BDE-99), and 2,2 ′,4,4 ′,6-pentabromodiphenyl ether (BDE-100), which are the primary components of the commonly used penta-BDE formulation flame retardant. Lake trout collected from Lake Huron had the highest concentrations of PBBs (3.1±1.7 ng/ g ww , 15±8.5 ng/ g lw ) , while the lowest levels were detected in fish from Lake Superior (0.25±0.13 ng/ g ww , 1.7±0.89 ng/ g lw ) . In all lake trout samples, 2,2 ′,4,4 ′,5,5 ′-hexabromobiphenyl (BB-153), a major constituent of the flame-retardant FireMaster BP-6 ®, was the predominant PBB congener.

Developmental neurotoxicity of polybrominated biphenyls

Female F 0 generation Sprague-Dawley rats received daily oral doses of 0, 0.2, or 2 mg/kg polybrominated biphenyls (PBB) as fireMaster BP-6 from Day 6 of gestation through Day 24 postpartum. Maternal parameters were assessed, and F 1 generation offspring were evaluated for growth and survival, as well as physical and behavioral development. No adverse maternal effects were observed nor were there PBB-related effects on survival of the F 1 generation or acquisition of developmental landmarks. Crown-rump length of 0.2 and 2 mg/kg male offspring was significantly less than that of controls and 2 mg/kg male and female offspring gained significantly less weight than did controls for the entire 60-day postnatal observation period. An overall evaluation of behavior by multivariate analysis of variance revealed significant PBB-related effects for acquisition of forward locomotion, cliff avoidance, cage emergence, and open-field activity of male and female offspring from dams administered 2 mg/kg. Delays in acquisition of forward locomotion and suppressed open-field activity were the most prominent effects. These indications of growth retardation and neurobehavioral toxicity occurred at concentrations of PBB in offspring body fat in the range of those which have been reported for highly exposed human subjects with neurological sequelae.

The effects of polybrominated biphenyls and perchlorinated terphenyls on in vitro fertilization in the mouse.

Polybrominated biphenyls (PBBs) and perchlorinated terphenyls (PCTs) are industrial chemicals that are long-lasting environmental contaminants. Although in vivo effects of PBBs on reproduction are documented, no information is available on the effects of these chemicals on sperm-egg interactions or fertilization. The present study was undertaken to determine the toxic potential of PBBs and PCTs on in vitro fertilization (IVF) in the mouse. 2-Bromobiphenyl, 4-bromobiphenyl, o-terphenyl, m-terphenyl, and p-terphenyl were added to the IVF medium at various concentrations. Oocytes collected from superovulated B6D2F1 mice were maintained in a medium containing the chemicals. Capacitated sperm were then added and the dishes cultured in a humidified atmosphere at 37 degrees C in 5% CO2 + 95% air. Oocytes were assessed for fertilization 20-24 h after insemination. polybrominated biphenyls and PCTs reduced the IVF rate at the higher dosages. Furthermore, an increased incidence of abnormal two-cell embryos and degenerative oocytes was observed at the 1 and 10 micrograms/ml concentrations of PBBs and PCTs. These results indicate that PBBs and PCTs adversely effect IVF and increase the incidence of abnormal embryos and oocyte degeneration in the mouse.

Effect of polybrominated biphenyls on the growth and maturation of human peripheral blood lymphocytes

Polybrominated biphenyls (PBB) have been shown to affect the immune system of exposed Michigan farm workers and their families. The purpose of this study was to evaluate the effects of PBB on the function and on the synthesis of immunoglobulins by peripheral blood lymphocytes. Concentrations of PBB as low as 0.001 μg 10 5 cells decreased lymphocyte response to pokeweed mitogen; higher concentrations of PBB stimulated the in vitro synthesis and release of immunoglobulins. PBB had no effect on the quantity of E-rosette-forming cells, the total T or B cells, or the ratio of helper to suppressor T-cell subpopulations. Enhanced release of IgG was identified in lymphocyte cultures obtained from blood specimens of PBB-exposed Michigan farmers. The data from this study suggest that PBB exerted an adverse effect on cell function, but produced a nonspecific activation of B lymphocytes.

Partitioning of polybrominated biphenyls (PBBs) in serum, adipose tissue, breast milk, placenta, cord blood, biliary fluid, and feces.

Polybrominated biphenyl (PBB) concentrations in specimens from adult males and females were used to determine the distribution of PBBs in body tissues and the partitioning ratio between types of tissues. Specimens of serum, adipose tissue, biliary fluid, and feces were tested by gas chromatography. In addition, parturient women provided breast milk, placenta, and cord blood for testing. There was a significant correlation between serum and adipose PBB levels. Pregnant and nonpregnant women and male chemical workers had similar serum to adipose tissue concentration ratios, which ranged from 1:140 to 1:260. Males from farms had a significantly different ratio of 1:325-329. Potential exposure to the fetus and newborn was demonstrated. Cord blood contained one-tenth of the concentration found in maternal serum which indicated partial placental passage. Human milk contained PBBs at 107 to 119 times the quantity found in maternal serum. Polybrominated biphenyls were detectable in bile and feces demonstrating transfer into the intestinal tract. The concentration of PBBs in feces represented a minor proportion of the total body burden indicating a slow rate of excretion.

Human Tissue Burdens of Halogenated Aromatic Chemicals in Michigan

A cross section of the population of Michigan was studied in 1978 to evaluate residual burdens of polybrominated biphenyls (PBBs), a flame-retardant chemical that had contaminated the state's food supply five years earlier. Levels of PBB were measured in serum specimens in 1,681 people and in adipose samples in 844. Ninety-seven percent of the adipose samples had detectable PBB concentrations. Levels of PBB were highest in that part of the state where meat and dairy products had been most contaminated and were lowest in the upper peninsula, farthest from the source. Levels for the rest of the state were in between. Polychlorinated biphenyls (PCB) and 2,2'-bis(p-chlorophenyl)-1, 1-dichloroethylene (p,p'-DDE), a dichlorodiphenyltrichloroethane (DDT) residue, were also measured, and variations of PBB, PCB, and p,p'-DDE levels with age and sex were investigated.

Effects of lactation and nursing on tissue concentrations of polybrominated biphenyls and on microsomal enzyme activity in mammary gland and liver in maternal rats

Redistribution of polybrominated biphenyls (PBBs) during the recovery period following lactation resulted in concentrations of PBBs that were higher in mammary gland and lower in liver and fat than at the end of lactation. Hepatic arylhydrocarbon hydroxylase (AHH) and epoxide hydrolase (EH) activities were higher in PBB-treated rats during lactation than in the recovery period. However, transition from lactating to dry state had no effect on activity of mammary gland AHH in rats treated with PBBs. Microsomal enzyme activity and concentrations of PBBs in mammary gland and liver were reduced by nursing a second litter. Although redistribution and excretion of PBBs resulted in alterations in microsomal enzyme activity, all rats exposed to 100 ppm PBBs had microsomal enzyme activity in liver and mammary gland that was higher than that in controls. Persistent stimulation of mammary gland and hepatic microsomal enyzmes while mothers are exposed to PBBs may affect not only mothers and offspring suckling but subsequent progeny as well.

Performance and Health of Offspring of Cows Experimentally Exposed to Polybrominated Biphenyls

Offspring of cows experimentally given polybrominated biphenyls (fire-Master BP-6) were studied from May 1976 through January 1981. Daily doses were 0, .25, and 250mg for 60 days for Groups I, II, and III, and 250mg for 180 or 202 days for Group V. Concentrations of polybrominated biphenyls in fat of dosed animals in Groups I, II, III, and V were .05, .20, 25, and 30μg/g at the end of dosing. Residue concentrations in body fat declined with a half life of about 1 yr. Seventy-five calves were born to these cows and their offspring, representing first through fifth parturition. Fifteen calves died, 10 of which were in Groups III and V. All deaths in Groups III and V were attributable to dystocia. Incidence of dystocia and calf mortality were related to birth weight of the calf which in turn was correlated with concentrations of polybrominated biphenyls in blood and tissues of the dam. Other variables that influenced birth weight were sex of calf, length of gestation, and parturition number of dam. There were no significant differences in growth and performance of calves from the four dosed groups. Clinical signs of polybrominated biphenyl toxicosis were not evident, and general health of offspring was not influenced. Number of inseminations for conception was greater among offspring from Groups III and V. Mechanisms for this dysfunction have not been determined.

Evidence of degradation of polybrominated biphenyls in soil samples from Michigan.

Soil samples obtained from the former polybrominated biphenyls (PBB) manufacturing site in Michigan were analyzed by gas chromatography and gas chromatography with mass spectrometric detection. The results indicate significant degradation of the PBB residue in the soil sample. The soil sample with the highest concentration of PBB had the greatest degree of degradation. Principal degradation products include 2,3', 4,4', 5-pentabromobiphenyl, 2,2', 4,4', 5-pentabromobiphenyl and two unidentified tetrabromobiphenyls. The degradation pattern observed supports a photochemical decomposition mechanism. These degraded residues may be more toxic than the original Firemaster residues. The implications of the results are discussed.