Richard S Jones

University of California, Berkeley, Berkeley, CA, USA

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Publications (19)94.54 Total impact

  • Article: Factors associated with serum polybrominated diphenyl ether (PBDE) levels among school-age children in the CHAMACOS cohort.
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    ABSTRACT: Polybrominated diphenyl ethers (PBDEs) are a class of flame retardants historically used in textiles, furniture, and electronic products. Recent studies have documented widespread PBDE exposure to humans, with higher levels measured in children than adults. We analyzed 10 tri- to hepta-BDE congener levels in blood collected from 7-year old Mexican-American children living in an agriculture community in California (n = 272). The most frequently detected PBDE congeners in child serum were BDE-47, -99, -100, and -153, all of which were measured in >99% of the children. We used multiple linear regression models to examine associations between child total PBDE levels (ng/g lipid) and determinants of exposure. Factors positively associated with higher PBDE levels in the children were total PBDE levels in maternal serum during pregnancy, duration of exclusive breastfeeding, and having no safe places to play in their neighborhood. Child BMI was inversely associated with serum PBDE levels (regression p-values <0.05). Our findings confirm that exposure to the penta-BDE mixture is ongoing, and that Mexican-American children living in California may be experiencing higher PBDE exposure from their environment compared to children sampled from the general U.S. population. Additional research is needed to assess the health impacts of these exposures.
    Environmental Science & Technology 06/2012; 46(13):7373-81. · 4.80 Impact Factor
  • Article: Determinants of serum polybrominated diphenyl ether (PBDE) levels among pregnant women in the CHAMACOS cohort.
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    ABSTRACT: We measured levels of 10 polybrominated diphenyl ether (PBDE) congeners in serum collected during pregnancy and at delivery from 416 pregnant, predominantly immigrant, women living in Monterey County, CA. The most frequently detected congeners were BDE-47, -99, -100, and -153, all components of the penta mixture, detected in >97% of samples. We used multivariable regression models to examine factors associated with exposure to individual PBDE congeners as well as their total summed concentration (ng/g lipid). Prenatal and delivery total PBDE levels were correlated between sampling times (n = 21; Pearson r = 0.99, p < 0.001). In multivariable models, total PBDE levels increased significantly with time residing in the U.S. (p < 0.001) and among women with ≥3 pieces of stuffed furniture in their homes (p < 0.05). Women's total PBDE levels increased 4.0% (95% CI = 2.8, 5.3) for each additional year residing in the U.S., after adjustment for prepregnancy BMI, weight gain during pregnancy, and SES. Having ≥3 pieces of stuffed furniture in the home was associated with a 26.8% (95% CI = 2.0, 57.5) increase in women's serum PBDE levels. Findings suggest PBDE indoor contamination in California homes is contributing to human exposures in a population of recent immigrants.
    Environmental Science & Technology 08/2011; 45(15):6553-60. · 4.80 Impact Factor
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    Article: Low dose organochlorine pesticides and polychlorinated biphenyls predict obesity, dyslipidemia, and insulin resistance among people free of diabetes.
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    ABSTRACT: There is emerging evidence that background exposure to persistent organic pollutants (POPs) are important in the development of conditions predisposing to diabetes as well as of type 2 diabetes itself. We recently reported that low dose POPs predicted incident type 2 diabetes in a nested case-control study. The current study examined if low dose POPs predicted future adiposity, dyslipidemia, and insulin resistance among controls without diabetes in that study. The 90 controls were diabetes-free during 20 years follow-up. They were a stratified random sample, enriched with overweight and obese persons. POPs measured in 1987-88 (year 2) sera included 8 organochlorine (OC) pesticides, 22 polychlorinated biphenyls (PCBs), and 1 polybrominated biphenyl (PBB). Body mass index (BMI), triglycerides, HDL-cholesterol, LDL-cholesterol, and homeostasis model assessment value for insulin resistance (HOMA-IR) were study outcomes at 2005-06 (year 20). The evolution of study outcomes during 18 years by categories of serum concentrations of POPs at year 2 was evaluated by adjusting for the baseline values of outcomes plus potential confounders. Parallel to prediction of type 2 diabetes, many statistically significant associations of POPs with dysmetabolic conditions appeared at low dose, forming inverted U-shaped dose-response relations. Among OC pesticides, p,p'-DDE most consistently predicted higher BMI, triglycerides, and HOMA-IR and lower HDL-cholesterol at year 20 after adjusting for baseline values. Oxychlordane, trans-nonachlor, and hexachlorobenzene also significantly predicted higher triglycerides. Persistent PCBs with ≥7 chlorides predicted higher BMI, triglycerides, and HOMA-IR and lower HDL-cholesterol at year 20 with similar dose-response curves. Simultaneous exposure to various POPs in the general population may contribute to development of obesity, dyslipidemia, and insulin resistance, common precursors of type 2 diabetes and cardiovascular diseases. Although obesity is a primary cause of these metabolic abnormalities, POPs exposure may contribute to excess adiposity and other features of dysmetabolism.
    PLoS ONE 01/2011; 6(1):e15977. · 4.09 Impact Factor
  • Article: A method for rapid, non-targeted screening for environmental contaminants in household dust.
    Donald C Hilton, Richard S Jones, Andreas Sjödin
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    ABSTRACT: Household dust can be a major source of human exposure to environmental contaminants such as polybrominated diphenyl ethers, pesticides, and other compounds. This work shows a screening technique that may be used to identify components in an environmental sample as xenobiotics based on mass spectral characteristics of classes of compounds that may be expected to be present in the environment. Household dust (SRM-2585) from the National Institute of Standards and Technology (NIST) was extracted with hexane using accelerated solvent extraction. Large molecules, such as triglycerides and fatty acids were removed with gel permeation chromatography. The extract was then concentrated and analyzed by comprehensive two dimensional gas chromatography coupled to a time of flight mass spectrometer. The resulting peak table was automatically filtered to identify compound classes such as phthalates, polycyclic aromatic hydrocarbons and their heterocyclic analogs, chlorinated compounds, brominated compounds, and nitro compounds. While phthalates can be identified by abundances at specific masses, the identification of the remaining classes is based on the identification of the molecular ion and identification of isotope clusters or other spectral characteristics. The technique detected compounds identified and quantified by NIST as well as compounds not identified by NIST in the sample. By comparison with concentrations determined by NIST for the analytes found, the technique is able to identify analytes in these compound classes at concentrations as low as 10-20 ng/g dust.
    Journal of chromatography. A 10/2010; 1217(44):6851-6. · 4.19 Impact Factor
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    Article: Prenatal exposure to PBDEs and neurodevelopment.
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    ABSTRACT: Polybrominated diphenyl ethers (PBDEs) are widely used flame retardant compounds that are persistent and bioaccumulative and therefore have become ubiquitous environment contaminants. Animal studies suggest that prenatal PBDE exposure may result in adverse neurodevelopmental effects. In a longitudinal cohort initiated after 11 September 2001, including 329 mothers who delivered in one of three hospitals in lower Manhattan, New York, we examined prenatal PBDE exposure and neurodevelopment when their children were 12-48 and 72 months of age. We analyzed 210 cord blood specimens for selected PBDE congeners and assessed neurodevelopmental effects in the children at 12-48 and 72 months of age; 118, 117, 114, 104, and 96 children with available cord PBDE measurements were assessed at 12, 24, 36, 48, and 72 months, respectively. We used multivariate regression analyses to evaluate the associations between concentrations of individual PBDE congeners and neurodevelopmental indices. Median cord blood concentrations of PBDE congeners 47, 99, and 100 were 11.2, 3.2, and 1.4 ng/g lipid, respectively. After adjustment for potential confounders, children with higher concentrations of BDEs 47, 99, or 100 scored lower on tests of mental and physical development at 12-48 and 72 months. Associations were significant for 12-month Psychomotor Development Index (BDE-47), 24-month Mental Development Index (MDI) (BDE-47, 99, and 100), 36-month MDI (BDE-100), 48-month full-scale and verbal IQ (BDE-47, 99, and 100) and performance IQ (BDE-100), and 72-month performance IQ (BDE-100). This epidemiologic study demonstrates neurodevelopmental effects in relation to cord blood PBDE concentrations. Confirmation is needed in other longitudinal studies.
    Environmental Health Perspectives 05/2010; 118(5):712-9. · 7.04 Impact Factor
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    Article: Low dose of some persistent organic pollutants predicts type 2 diabetes: a nested case-control study.
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    ABSTRACT: Low doses of some persistent organic pollutants (POPs) associate cross-sectionally with type 2 diabetes, whereas associations with high POP exposures are inconsistent. We investigated whether several POPs prospectively predict type 2 diabetes within the Coronary Artery Risk Development in Young Adults (CARDIA) cohort. Participants in this nested case-control study were diabetes free in 1987-1988. By 2005-2006, the 90 controls remained free of diabetes, whereas the 90 cases developed diabetes. Using serum collected in 1987-1988, we measured 8 organochlorine pesticides, 22 polychlorinated biphenyl congeners (PCBs), and 1 polybrominated biphenyl (PBB). We compared POP concentrations from CARDIA and the National Health and Nutrition Examination Survey (NHANES) in 2003-2004. We computed odds ratios (ORs) for incident diabetes using logistic regression analysis. Chlorinated POPs in CARDIA in 1987-1988 were much higher than corresponding NHANES 2003-2004 concentrations. POPs showed nonlinear associations with diabetes risk. The highest risk was observed in the second quartiles of trans-nonachlor, oxychlordane, mirex, highly chlorinated PCBs, and PBB153-a finding that suggests low-dose effects. We concentrated risk by summing these POPs and isolated very low concentrations of multiple POPs in the lowest sextile of the sum. The adjusted OR in the second sextile vs. the lowest sextile was 5.3 overall and 20.1 for body mass index > or = 30 kg/m2. Several POPs at low doses similar to current exposure levels may increase diabetes risk, possibly through endocrine disruption. Certain POPs may a play a role in the current epidemic of diabetes, which has been attributed to obesity.
    Environmental Health Perspectives 05/2010; 118(9):1235-42. · 7.04 Impact Factor
  • Article: Response to "An assessment of the human health risks from exposure to polybrominated diphenyl ethers (PBDEs) in house dust" by Marek Banasik et al.
    Chemosphere 10/2009; · 3.21 Impact Factor
  • Article: Concentration of polybrominated diphenyl ethers (PBDEs) in household dust from various countries.
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    ABSTRACT: Seven polybrominated diphenyl ether (PBDE) congeners were measured in the particulate fraction (<2mm) of household dust samples (n=40), collected in four different countries (Australia, Germany, Great Britain, and United States). Dust samples from Germany contained the lowest concentrations of total PBDEs (median: 74 ng/g, range: 17-550 ng/g dust). Australian dust contained the second lowest concentration (median: 1200 ng/g, range: 500-13,000 ng/g dust). The dust from the United States and Great Britain contained the highest measured amounts of total PBDEs (US median: 4200 ng/g dust, range: 520-29,000 ng/g; Great Britain median: 10,000 ng/g, range: 950-54,000 ng/g). Daily intake of PBDEs has been estimated from published reference values on daily dust intake rates. The highest daily intake of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) found was in the United States (<1-330 ng/day) and the lowest was in Germany (<1-2 ng/day). The PBDE congeners present in commercially available pentabromodiphenyl ether were the highest in concentration in the United States, and the congener distribution was similar to that of the technical preparation (i.e., 2,2',4,4',5-pentabromodiphenyl ether [BDE-99] was similar in concentration to that of BDE-47). We conclude that further studies are required to investigate human indoor exposure to PBDEs across countries and to determine the risk factors related to indoor design factors.
    Chemosphere 05/2008; 73(1 Suppl):S131-6. · 3.21 Impact Factor
  • Article: Serum levels of polybrominated diphenyl ethers (PBDEs) in foam recyclers and carpet installers working in the United States.
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    ABSTRACT: Increased exposure to the flame retardants known as polybrominated diphenyl ethers (PBDEs) may be expected to occur during the recycling of polyurethane foam containing these chemicals. To date, no studies in the United States have investigated occupational exposure to these flame retardants during recycling processes. The objective of the present study was to determine if individuals working in foam recycling facilities, and/or carpet installers who may install carpet padding manufactured from recycled foam, possess significantly higher PBDE serum levels relative to that of the general U.S. population. As a control group, serum was collected from four spouses and one clerical worker. In addition, levels in workers were also compared to the recently published national health and nutrition examination survey (NHANES) data set on PBDEs in the general U.S. population. Serum samples were collected in duplicate and analyzed by two different laboratories as quality control. Total PBDE levels were found to be significantly higher (p < 0.05) in the individuals recycling foam and installing carpet (n = 15) relative to the control group (n = 5). Median sigmaPBDE levels in the foam recyclers, carpet layers, and control group were 160, 178, and 19 ng/g lipid, respectively. In contrast, concentrations of a polybrominated biphenyl (BB-153) and a polychlorinated biphenyl (CB-153) were equivalent among all groups tested. The PBDE congeners BDE-47, 99, 100, and 153 contributed 90% of the sigmaPBDE concentration in serum and no differences in congener patterns were apparent among the different groups. Relative to concentrations measured in the NHANES, foam recyclers and carpet layers have body burdens that are an order of magnitude higher. These data suggest individuals recycling foam-containing products, and/ or using products manufactured from recycled foam (i.e., carpet padding), have higher body burdens of PBDEs, and thus may be at higher risk from adverse health effects associated with brominated flame retardant exposure.
    Environmental Science and Technology 05/2008; 42(9):3453-8. · 5.23 Impact Factor
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    Article: Serum concentrations of polybrominated diphenyl ethers (PBDEs) and polybrominated biphenyl (PBB) in the United States population: 2003-2004.
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    ABSTRACT: Polybrominated diphenyl ethers (PBDEs) and 2,2',4,4',5,5'-hexabromobiphenyl (BB-153) are chemicals known as brominated flame retardants. We have assessed the exposure status of the United States population to PBDEs and BB-153 and explored associations with demographic information, including participants' age, sex, and race/ethnicity. A total of 2,062 serum samples, from participants in the National Health and Nutrition Examination Survey (NHANES) 2003-2004 aged 12 years and older, were analyzed for PBDEs and BB-153; stratified and regression analyses were used to examine levels among demographic groups. The congener with the highest serum concentration was 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) [geometric mean 20.5 ng/g lipid]; followed by 2,2',4,4',5,5'-hexaBDE (BDE-153) [5.7 ng/g lipid]; 2,2',4,4',5-pentaBDE (BDE-99) [5.0 ng/g lipid; a value equal to the highest limit of detection for an individual sample]; 2,2',4,4',6-pentaBDE (BDE-100) [3.9 ng/g lipid]; BB-153 [2.3 ng/g lipid]; and 2,4,4'-triBDE (BDE-28) [1.2 ng/g lipid]. For BDE-47, we observed no significant difference in the least-squares geometric mean (LSGM) by sex, but with age we found both a linear decrease (p = 0.01) and a positive quadratic trend (p = 0.01). Its LSGM, 27.9 ng/lipid, in the 12-19 year olds decreased to 17.2 ng/g lipid in the 40-49 year group, and then curved upward to 20.4 ng/g lipid in the > or =60 years olds. Mexican Americans had the highest LSGM of BDE-47 (24.5 ng/g lipid), which was significantly higher than that of non-Hispanic whites (19.7 ng/g lipid, p = 0.01). Adults 60 years and older were twice as likely as adults 20-59 years old to have a serum BDE-47 concentration above the 95th percentile (p = 0.02). These data provide needed exposure assessment data for public health decisions.
    Environmental Science and Technology 02/2008; 42(4):1377-84. · 5.23 Impact Factor
  • Article: Serum Concentrations of Polybrominated Diphenyl Ethers (PBDEs) and Polybrominated Biphenyl (PBB) in the United States Population: 2003–2004
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    ABSTRACT: Polybrominated diphenyl ethers (PBDEs) and 2,2′,4,4′,5,5′-hexabromobiphenyl (BB-153) are chemicals known as brominated flame retardants. We have assessed the exposure status of the United States population to PBDEs and BB-153 and explored associations with demographic information, including participants’ age, sex, and race/ethnicity. A total of 2,062 serum samples, from participants in the National Health and Nutrition Examination Survey (NHANES) 2003–2004 aged 12 years and older, were analyzed for PBDEs and BB-153; stratified and regression analyses were used to examine levels among demographic groups. The congener with the highest serum concentration was 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) [geometric mean 20.5 ng/g lipid]; followed by 2,2′,4,4′,5,5′-hexaBDE (BDE-153) [5.7 ng/g lipid]; 2,2′,4,4′,5-pentaBDE (BDE-99) [5.0 ng/g lipid; a value equal to the highest limit of detection for an individual sample]; 2,2′,4,4′,6-pentaBDE (BDE-100) [3.9 ng/g lipid]; BB-153 [2.3 ng/g lipid]; and 2,4,4′-triBDE (BDE-28) [1.2 ng/g lipid]. For BDE-47, we observed no significant difference in the least-squares geometric mean (LSGM) by sex, but with age we found both a linear decrease (p = 0.01) and a positive quadratic trend (p = 0.01). Its LSGM, 27.9 ng/lipid, in the 12–19 year olds decreased to 17.2 ng/g lipid in the 40–49 year group, and then curved upward to 20.4 ng/g lipid in the ≥60 years olds. Mexican Americans had the highest LSGM of BDE-47 (24.5 ng/g lipid), which was significantly higher than that of non-Hispanic whites (19.7 ng/g lipid, p = 0.01). Adults 60 years and older were twice as likely as adults 20–59 years old to have a serum BDE-47 concentration above the 95th percentile (p = 0.02).These data provide needed exposure assessment data for public health decisions.
    01/2008;
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    Article: Determinants of prenatal exposure to polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in an urban population.
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    ABSTRACT: Recent studies have reported blood levels of polybrominated diphenyl ethers (PBDEs) in the U.S. population. Information about neonatal levels and about the relationship to polychlorinated biphenyls (PCBs) exposures is limited. The objective was to characterize levels and determinants of fetal exposure to PBDEs and PCBs among newborns from Baltimore, Maryland. We analyzed umbilical cord blood for eight PBDEs and 35 PCBs from infants delivered at the Johns Hopkins Hospital. Maternal and infant characteristics were abstracted from medical records. Ninety-four percent of cord serum samples had quantifiable levels of at least one PBDE congener, and > 99% had at least one detectable PCB congener. PBDE concentrations in cord blood were similar to those reported in other studies from North America. Strong correlations were observed within but not across PCB and PBDE classes. Multivariate models showed that many factors independently predicted exposure to BDE-47, BDE-100, and BDE-153 and CB-118, CB-138/158, CB-153, and CB-180. Generally, infants of Asian mothers had lower PBDE and PCB levels, and infants of smokers had higher levels. Increased maternal body mass index was associated with lower levels of PCBs but not PBDEs. Levels of PCBs but not PBDEs were lower in births from married and multiparous mothers. Increased maternal age was associated with higher PCB levels but lower PBDE levels. Although many of the factors we investigated were independent predictors of both PBDE and PCB levels, in some cases the direction of associations was different. More research is needed to better understand the sources and pathways of PBDE exposure.
    Environmental Health Perspectives 12/2007; 115(12):1794-800. · 7.04 Impact Factor
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    Article: Polybrominated diphenyl ether levels in the blood of pregnant women living in an agricultural community in California.
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    ABSTRACT: Recent studies have raised concerns about polybrominated diphenyl ether (PBDE) flame retardant exposures to pregnant women and women of child-bearing age in the United States. Few studies have measured PBDEs in immigrant populations. Our goal was to characterize levels of seven PBDE congeners, polychlorinated biphenyl (PCB)-153, and polybrominated biphenyl (PBB)-153 in plasma from 24 pregnant women of Mexican descent living in an agricultural community in California. The median concentration of the sum of the PBDE congeners was 21 ng/g lipid and ranged from 5.3 to 320 ng/g lipid. Consistent with other studies, 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) was found at the highest concentration (median = 11 ng/g lipid; range, 2.5-205) followed by 2,2',4,4',5-pentabromobiphenyl (BDE-99) (median = 2.9 ng/g lipid; range, 0.5-54), 2,2',4,4',5-pentaBDE (BDE-100) (median = 1.8 ng/g lipid; range, 0.6-44), and 2,2',4,4',5,5'-hexaBDE (BDE-153) (median = 1.5 ng/g lipid; range, 0.4-35). Levels of PCB-153 (median= 4.4 ng/g lipid; range, < 2-75) were lower than U.S. averages and uncorrelated with PBDE levels, suggesting different exposure routes. The overall levels of PBDEs found were lower than levels observed in other U.S. populations, although still higher than those observed previously in Europe or Japan. The upper range of exposure is similar to what has been reported in other U.S. populations. PBDEs have been associated with adverse developmental effects in animals. Future studies are needed to determine the sources and pathways of PBDE exposures and whether these exposures have adverse effects on human health.
    Environmental Health Perspectives 02/2007; 115(1):71-4. · 7.04 Impact Factor
  • Article: Measurement of urinary monohydroxy polycyclic aromatic hydrocarbons using automated liquid-liquid extraction and gas chromatography/isotope dilution high-resolution mass spectrometry.
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    ABSTRACT: A method for the measurement of 24 hydroxylated polycyclic aromatic hydrocarbon metabolites (OH-PAHs) in urine has been developed. The method is based on enzymatic deconjugation, automated liquid-liquid extraction, and gas chromatography/isotope dilution high-resolution mass spectrometry after derivatization of the OH-PAHs to the trimethylsilylated derivatives. The metabolites included in the current method are formed from eight different parent compounds. The limits of detection were below 7 pg/mL when using a sample size of 2 mL of urine, except for 1- and 2-naphthols (18 and 12 pg/mL, respectively). The enzymatic deconjugation efficiency, verified by deconjugation of urine samples spiked with alpha-naphthyl beta-d-glucuronide sodium salt (1-NAP-GLU) and pyrene-1-sulfate potassium salt (1-PYR-SULF), was determined to be 97% for 1-NAP-GLU conjugate and 84% for 1-PYR-SULF. The overall coefficients of variance for six batches of quality control samples (n = 42), was 2.9-11%. Mean method recoveries of the 13C-labeled internal standards were 66-72%, except for 13C6-1-naphthol (46%). The throughput of this method has been determined to be 40 samples per day per analyst. This method is currently applied to epidemiological studies, such as the National Exposure and Nutrition Examination Survey (NHANES), to measure human exposure to PAHs.
    Analytical Chemistry 09/2006; 78(16):5744-51. · 5.86 Impact Factor
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    Article: Body burdens of polybrominated diphenyl ethers among urban anglers.
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    ABSTRACT: Polybrominated diphenyl ethers (PBDEs) have been widely used in the United States and worldwide as flame retardants. Recent PBDE production figures show that worldwide use has increased. To determine whether fish consumption is a source of PBDE exposure for humans, a cross-sectional epidemiologic study of New York and New Jersey urban anglers was conducted during the summers of 2001-2003. Frequency of local fish consumption was assessed by questionnaire, and blood samples for PBDE analysis were collected from 94 anglers fishing from piers on the lower Hudson River and Newark Bay. We analyzed PBDEs by gas chromatography-isotope dilution-high-resolution mass spectrometry. The congeners found in anglers' serum at the highest concentrations were, by International Union of Pure and Applied Chemistry numbers, BDE-47, BDE-153, and BDE-99. Anglers reporting consumption of local fish had higher, but nonstatistically significantly different, concentrations of PBDEs than did anglers who did not eat local fish. For some congeners (BDE-100 and BDE-153), we observed moderate dose-response relationships between serum PBDE levels and frequency of reported fish intake. These findings suggest that consumption of locally caught fish is not a major route of human exposure for this study population.
    Environmental Health Perspectives 01/2006; 113(12):1689-92. · 7.04 Impact Factor
  • Article: Semiautomated high-throughput extraction and cleanup method for the measurement of polybrominated diphenyl ethers and polybrominated and polychlorinated biphenyls in breast milk.
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    ABSTRACT: A semiautomated extraction and cleanup method has been developed to measure eight polybrominated diphenyl ethers (PBDEs), 2,2',4,4',5,5'-hexabromobiphenyl (BB-153), and 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153). The method employs solid-phase dispersion on diatomaceous earth in a solid-phase extraction cartridge followed by automated addition of internal standards ((13)C-labeled). Extraction is then performed using an automated modular solid-phase extraction system. The extraction procedure includes drying the sample on diatomaceous earth by pressurized nitrogen and eluting target analytes and lipids with dichloromethane. Lipid content is determined gravimetrically. Lipid determinations performed using this method are compared with other standard methods and with a certified reference material. A relative standard deviation of 7.9% was obtained for 130 determinations of the lipid content in a breast milk quality control sample. Final analytical determination of target analytes was performed by gas chromatography-isotope dilution high-resolution mass spectrometry. Relative standard deviations for the measurements of target analytes for which a labeled internal standard was available were below 10% for analytes at concentrations above 1 ng/g of lipid. Mean recoveries of the (13)C-labeled internal standards ranged from 60 to 89% for the eight PBDE congeners; 74 and 113% were recovered for BB-153 and CB-153, respectively.
    Analytical Chemistry 09/2004; 76(15):4508-14. · 5.86 Impact Factor
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    Article: Retrospective time-trend study of polybrominated diphenyl ether and polybrominated and polychlorinated biphenyl levels in human serum from the United States.
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    ABSTRACT: Six polybrominated diphenyl ethers (PBDEs), one hexabromobiphenyl [polybrominated biphenyl (PBB)], and one hexachlorobiphenyl [polychlorinated biphenyl (PCB)] were measured in 40 human serum pools collected in the southeastern United States during 1985 through 2002 and in Seattle, Washington, for 1999 through 2002. The concentrations of most of the PBDEs, which are commercially used as flame retardants in common household and commercial applications, had significant positive correlations with time of sample collection, showing that the concentrations of these compounds are increasing in serum collected in the United States. In contrast, PCB and PBB levels were negatively correlated with sample collection year, indicating that the levels of these compounds have been decreasing since their phaseout in the 1970s.
    Environmental Health Perspectives 06/2004; 112(6):654-8. · 7.04 Impact Factor
  • Article: Semiautomated high-throughput extraction and cleanup method for the measurement of polybrominated diphenyl ethers, polybrominated biphenyls, and polychlorinated biphenyls in human serum.
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    ABSTRACT: A semiautomated extraction and cleanup method has been developed for the measurement of eight polybrominated diphenyl ethers (PBDEs), 2,2',4,4',5,5'-hexabromobiphenyl (BB-153) and 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153). The method employs automated addition of internal standards ((13)C-labeled), addition of formic acid (denaturation agent), and dilution with water prior to automated overnight extraction using a modular solid-phase extraction (SPE) system. Removal of coextracted biogenic materials was performed on a two-layered 3-mL disposable cartridge containing activated silica gel and a mixture of silica gel and sulfuric acid. Sample cleanup was automated using the same modular SPE system. Reproducibility and precision of the liquid handler used for internal standard additions were shown to be 2 and 4%, respectively. Overall reproducibility during processing of eight batches of samples (N = 30/batch, including methods blanks) was below 10% for most analytes. Mean recoveries of the (13)C-labeled internal standards ranged from 69 to 95% for the seven monitored PBDEs; 76 and 98% were recovered for BB-153 and CB-153, respectively.
    Analytical Chemistry 05/2004; 76(7):1921-7. · 5.86 Impact Factor
  • Article: Concentration of polybrominated diphenyl ethers (PBDEs) in household dust from various countries
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    ABSTRACT: Seven polybrominated diphenyl ether (PBDE) congeners were measured in the particulate fraction (<2 mm) of household dust samples (n = 40), collected in four different countries (Australia, Germany, Great Britain, and United States). Dust samples from Germany contained the lowest concentrations of total PBDEs (median: 74 ng/g, range: 17–550 ng/g dust). Australian dust contained the second lowest concentration (median: 1200 ng/g, range: 500–13,000 ng/g dust). The dust from the United States and Great Britain contained the highest measured amounts of total PBDEs (US median: 4200 ng/g dust, range: 520–29,000 ng/g; Great Britain median: 10,000 ng/g, range: 950–54,000 ng/g). Daily intake of PBDEs has been estimated from published reference values on daily dust intake rates. The highest daily intake of 2,20,4,40-tetrabromodiphenyl ether (BDE-47) found was in the United States (<1–330 ng/day) and the lowest was in Germany (<1–2 ng/day). The PBDE congeners present in commercially available pentabromodiphenyl ether were the highest in concentration in the United States, and the congener distribution was similar to that of the technical preparation (i.e., 2,20,4,40,5-pentabromodiphenyl ether [BDE-99] was similar in concentration to that of BDE-47). We conclude that further studies are required to investigate human indoor exposure to PBDEs across countries and to determine the risk factors related to indoor design factors.

Institutions

  • 2007–2012
    • University of California, Berkeley
      • School of Public Health
      Berkeley, CA, USA
  • 2004–2009
    • Centers for Disease Control and Prevention
      • • National Center for Environmental Health
      • • Division of Laboratory Sciences
      Druid Hills, GA, USA
  • 2008
    • Duke University
      Durham, NC, USA
  • 2006
    • Mount Sinai School of Medicine
      Manhattan, NY, USA