Fiona Harden

Queensland University of Technology, Brisbane, Queensland, Australia

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Publications (49)90.77 Total impact

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    ABSTRACT: PBDE concentrations are higher in children compared to adults with exposure suggested to include dust ingestion. Besides the home environment, children spend a great deal of time in school classrooms which may be a source of exposure. As part of the "Ultrafine Particles from Traffic Emissions and Children's Health (UPTECH)" project, dust samples (n=28) were obtained in 2011/12 from 10 Brisbane, Australia metropolitan schools and analysed using GC and LC-MS for polybrominated diphenyl ethers (PBDEs) -17, -28, -47, -49, -66, -85, -99, -100, -154, -183, and -209. Σ11PBDEs ranged from 11-2163ng/g dust; with a mean and median of 600 and 469ng/g dust, respectively. BDE-209 (range n.d. -2034ng/g dust; mean (median) 402 (217)ng/g dust) was the dominant congener in most classrooms. Frequencies of detection were 96%, 96%, 39% and 93% for BDE-47, -99, -100 and -209, respectively. No seasonal variations were apparent and from each of the two schools where XRF measurements were carried out, only two classroom items had detectable bromine. PBDE intake for 8-11 year olds can be estimated at 0.094ng/day BDE-47; 0.187ng/day BDE-99 and 0.522ng/day BDE-209 as a result of ingestion of classroom dust, based on mean PBDE concentrations. The 97.5% percentile intake is estimated to be 0.62, 1.03 and 2.14ng/day for BDEs-47, -99 and -209, respectively. These PBDE concentrations in dust from classrooms, which are higher than in Australian homes, may explain some of the higher body burden of PBDEs in children compared to adults when taking into consideration age-dependant behaviours which increase dust ingestion. Copyright © 2015 Elsevier Inc. All rights reserved.
    Environmental Research 10/2015; 142. DOI:10.1016/j.envres.2015.06.007 · 3.95 Impact Factor
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    ABSTRACT: Quantitative microbial risk assessment (QMRA) is the current method of choice for determining the risk to human health from exposure to microorganisms of concern. However, current approaches are often constrained by the availability of required data, and may not be able to incorporate the many varied factors that influence this risk. Systems models, based on Bayesian networks (BNs), are emerging as an effective complementary approach that overcomes these limitations. This article aims to provide a comparative evaluation of the capabilities and challenges of current QMRA methods and BN models, and a scoping review of recent published articles that adopt the latter for microbial risk assessment. Pros and cons of systems approaches in this context are distilled and discussed. A search of the peer-reviewed literature revealed 15 articles describing BNs used in the context of QMRAs for foodborne and waterborne pathogens. These studies were analysed in terms of their application, uses and benefits in QMRA. The applications were notable in their diversity. BNs were used to make predictions, for scenario assessment, risk minimisation, to reduce uncertainty and to separate uncertainty and variability. Most studies focused on a segment of the exposure pathway, indicating the broad potential for the method in other QMRA steps. BNs offer a number of useful features to enhance QMRA, including transparency, and the ability to deal with poor quality data and support causal reasoning. The method has significant untapped potential to describe the complex relationships between microbial environmental exposures and health. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.
    Environment international 07/2015; 80. DOI:10.1016/j.envint.2015.03.013 · 5.66 Impact Factor
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    ABSTRACT: Demonstrate the application of decision trees-classification and regression trees (CARTs), and their cousins, boosted regression trees (BRTs)-to understand structure in missing data. Data taken from employees at 3 different industrial sites in Australia. 7915 observations were included. The approach was evaluated using an occupational health data set comprising results of questionnaires, medical tests and environmental monitoring. Statistical methods included standard statistical tests and the 'rpart' and 'gbm' packages for CART and BRT analyses, respectively, from the statistical software 'R'. A simulation study was conducted to explore the capability of decision tree models in describing data with missingness artificially introduced. CART and BRT models were effective in highlighting a missingness structure in the data, related to the type of data (medical or environmental), the site in which it was collected, the number of visits, and the presence of extreme values. The simulation study revealed that CART models were able to identify variables and values responsible for inducing missingness. There was greater variation in variable importance for unstructured as compared to structured missingness. Both CART and BRT models were effective in describing structural missingness in data. CART models may be preferred over BRT models for exploratory analysis of missing data, and selecting variables important for predicting missingness. BRT models can show how values of other variables influence missingness, which may prove useful for researchers. Researchers are encouraged to use CART and BRT models to explore and understand missing data. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.
    BMJ Open 06/2015; 5(6):e007450. DOI:10.1136/bmjopen-2014-007450 · 2.06 Impact Factor
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    ABSTRACT: Bien Hoa and Da Nang airbases were bulk storages for Agent Orange during the Vietnam War and currently are the two most severe dioxin hot spots. This study assesses the health risk of exposure to dioxin through foods for local residents living in seven wards surrounding these airbases. This study follows the Australian Environmental Health Risk Assessment Framework to assess the health risk of exposure to dioxin in foods. Forty-six pooled samples of commonly consumed local foods were collected and analyzed for dioxin/furans. A food frequency and Knowledge-Attitude-Practice survey was also undertaken at 1000 local households, various stakeholders were involved and related publications were reviewed. Total dioxin/furan concentrations in samples of local "high-risk" foods (e.g. free range chicken meat and eggs, ducks, freshwater fish, snail and beef) ranged from 3.8pgTEQ/g to 95pgTEQ/g, while in "low-risk" foods (e.g. caged chicken meat and eggs, seafoods, pork, leafy vegetables, fruits, and rice) concentrations ranged from 0.03pgTEQ/g to 6.1pgTEQ/g. Estimated daily intake of dioxin if people who did not consume local high risk foods ranged from 3.2pgTEQ/kgbw/day to 6.2pgTEQ/kgbw/day (Bien Hoa) and from 1.2pgTEQ/kgbw/day to 4.3pgTEQ/kgbw/day (Da Nang). Consumption of local high risk foods resulted in extremely high dioxin daily intakes (60.4-102.8pgTEQ/kgbw/day in Bien Hoa; 27.0-148.0pgTEQ/kgbw/day in Da Nang). Consumption of local "high-risk" foods increases dioxin daily intakes far above the WHO recommended TDI (1-4pgTEQ/kgbw/day). Practicing appropriate preventive measures is necessary to significantly reduce exposure and health risk. Copyright © 2015 Elsevier GmbH. All rights reserved.
    International journal of hygiene and environmental health 04/2015; 218(5). DOI:10.1016/j.ijheh.2015.03.014 · 3.28 Impact Factor
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    ABSTRACT: Population pharmacokinetic models combined with multiple sets of age-concentration biomonitoring data facilitate back-calculation of chemical uptake rates from biomonitoring data. We back-calculated uptake rates of PBDEs for the Australian population from multiple biomonitoring surveys (top-down) and compared them to uptake rates calculated from dietary intake estimates of PBDEs and PBDE concentrations in dust (bottom-up). Using three sets of PBDE elimination half-lives, we applied a population pharmacokinetic model to the PBDE biomonitoring data measured between 2002/03 and 2010/11 to derive the top-down uptake rates of four key PBDE congeners and six age groups. For the bottom-up approach we used PBDE concentrations measured around 2005. Top-down uptake rates of ∑4BDE varies from 7.9 to 19 ng/kg/d for toddlers and from 1.2 to 3.0 ng/kg/d for adults; in most cases, they are for all age groups higher than the bottom-up uptake rates. The discrepancy was largest for toddlers with factors up to 7-15 depending on the congener. Despite different elimination half-lives of the four congeners, the age-concentration trends showed no increase in concentration with age and were similar for all congeners. In the bottom-up approach, PBDE uptake is underestimated; currently known pathways are not sufficient to explain measured PBDE concentrations, especially in young children. While PBDE exposure of toddlers has declined in the past years, pre- and postnatal exposure to PBDEs has remained almost constant because the mothers' PBDE body burden has not yet decreased substantially.
    Environmental Health Perspectives 03/2015; DOI:10.1289/ehp.1408960 · 7.03 Impact Factor
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    ABSTRACT: Severe dioxin contamination at Bien Hoa and Da Nang airbases, Vietnam is of international concern. Public Health risk reduction programs were implemented in Bien Hoa in 2007-2009 and in Da Nang in 2009-2011. In 2009 and 2011 we reported the encouraging results of these interventions in improving the knowledge, attitude and practices (KAP) of local residents in reducing the dioxin exposure risk through foods. In 2013 we revisited these dioxin hot spots, aimed to evaluate whether the results of the intervention were maintained and to identify factors affecting the sustainability of the programs. To assess this, 16 in-depth interviews, six focus group discussions, and pre and post intervention KAP surveys were undertaken. 800 respondents from six intervention wards and 200 respondents from Buu Long Ward (the control site) were randomly selected to participate in the surveys. The results showed that as of 2013, the programs were rated as "moderately sustained" with a score of 3.3 out of 5.0 (cut off points 2.5 to <3.5) for Bien Hoa, and "well sustained" with a score of 3.8 out of 5.0 (cut off points 3.5 to <4.5) for Da Nang. Most formal intervention program activities had ceased and dioxin risk communication activities were no longer integrated into local routine health education programs. However, the main outcomes were maintained and were better than that in the control ward. Migration, lack of official guidance from City People's Committees and local authorities as well as the politically sensitive nature of dioxin issues were the main challenges for the sustainability of the programs.
    Journal of Community Health 12/2014; 40(4). DOI:10.1007/s10900-014-9980-1 · 1.28 Impact Factor
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    ABSTRACT: Contexte La chimiothérapie à base de cisplatine est de plus en plus le traitement retenu pour les patients atteints du cancer de la tête ou du cancer du cou. La surdité neurosensorielle, important effet secondaire à long terme de la chimioradiothérapie à base de cisplatine, pourrait entraîner une grande détérioration de la qualité de vie des patients traités. Objet Ce manuscrit avait pour objet d'examiner le mécanisme qui sous-tend la surdité neurosensorielle chez les patients qui subissent des traitements de chimioradiothérapie à base de cisplatine, dont l'incidence de cette affection, l'influence de la radiothérapie et du cisplatine sur celle-ci et l'impact de la toxicité sur la qualité de vie des patients. Méthodes Des recherches ont été effectuées dans des bases de données par l'intermédiaire de PubMed (National Centre for Biotechnolgy Information) et d'OvidSP Medline via le site Web de la bibliothèque de la Queensland University of Technology. En outre, des recherches générales d'articles ont été réalisées à l'aide du moteur de recherche en ligne Google Scholar. Les articles dont le contenu intégral n'était pas accessible et ceux qui n'étaient pas en anglais ou qui avaient été publiés avant 1990 ont été rejetés. Les mots-clés utilisés pour les recherches étaient hearing loss, ototoxicity, cancer, quality of life, cisplatin et radiotherapy. Résultats/Analyse Au total, les recherches ont donné accès à 290 articles. Après un tri basé sur les critères d'exclusion mentionnés ci-dessus, 129 de ces articles ont été jugés appropriés aux fins de l'examen. Il ressort de l'examen que la surdité neurosensorielle est un important effet secondaire à long terme chez les patients qui subissent des traitements de chimioradiothérapie à base de cisplatine. La littérature scientifique courante indique que les effets ototoxiques du cisplatine et l'irradiation crânienne sont considérés comme des entités distinctes; toutefois, il est rare qu'on aborde l'impact des traitements combinés de radiothérapie et de chimiothérapie sur la surdité neurosensorielle. Les facteurs de risque multiples liés à la surdité sont décrits, mais les opinions divergent quant à l'incidence et à la gravité de cet effet ainsi qu'au seuil de dose de rayonnement exact au-delà duquel les traitements combinés de radiothérapie et de chimiothérapie causent la surdité neurosensorielle chez les patients. Cette surdité induit un sous-ensemble de complexités chez les patients atteints du cancer de la tête ou du cancer du cou, qui subissent une importante diminution de leur qualité de vie. Conclusion La revue de la littérature réalisée révèle que la surdité neurosensorielle est un important effet secondaire chez les patients atteints du cancer de la tête ou du cancer du cou qui subissent des traitements de chimioradiothérapie à base de cisplatine. Il y a lieu de pousser la recherche afin d'évaluer la contribution de la chimioradiothérapie à base de cisplatine à la surdité neurosensorielle et l'effet ultérieur sur la qualité de vie des patients traités.
    Journal of Medical Imaging and Radiation Sciences 09/2014; 45(3). DOI:10.1016/j.jmir.2013.11.003
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    ABSTRACT: Some perfluoroalkyl and polyfluoroalkyl substances (PFASs) have become widespread pollutants detected in human and wildlife samples worldwide. The main objective of this study was to assess temporal trends of PFAS concentrations in human blood in Australia over the last decade (2002-2011), taking into consideration age and sex trends. Pooled human sera from 2002/03 (n=26); 2008/09 (n=24) and 2010/11 (n=24) from South East Queensland, Australia were obtained from de-identified surplus pathology samples and compared with samples collected previously from 2006/07 (n=84). A total of 9775 samples in 158 pools were available for an assessment of PFASs. Stratification criteria included sex and age: <16years (2002/03 only); 0-4 (2006/07, 2008/09, 2010/11); 5-15 (2006/07, 2008/09, 2010/11); 16-30; 31-45; 46-60; and >60years (all collection periods). Sera were analyzed using on-line solid-phase extraction coupled to high-performance liquid chromatography-isotope dilution-tandem mass spectrometry. Perfluorooctane sulfonate (PFOS) was detected in the highest concentrations ranging from 5.3-19.2ng/ml (2008/09) to 4.4-17.4ng/ml (2010/11). Perfluorooctanoate (PFOA) was detected in the next highest concentration ranging from 2.8-7.3ng/ml (2008/09) to 3.1-6.5ng/ml (2010/11). All other measured PFASs were detected at concentrations <1ng/ml with the exception of perfluorohexane sulfonate which ranged from 1.2-5.7ng/ml (08/09) and 1.4-5.4ng/ml (10/11). The mean concentrations of both PFOS and PFOA in the 2010/11 period compared to 2002/03 were lower for all adult age groups by 56%. For 5-15year olds, the decrease was 66% (PFOS) and 63% (PFOA) from 2002/03 to 2010/11. For 0-4year olds the decrease from 2006/07 (when data were first available for this age group) was 50% (PFOS) and 22% (PFOA). This study provides strong evidence for decreasing serum PFOS and PFOA concentrations in an Australian population from 2002 through 2011. Age trends were variable and concentrations were higher in males than in females. Global use has been in decline since around 2002 and hence primary exposure levels are expected to be decreasing. Further biomonitoring will allow assessment of PFAS exposures to confirm trends in exposure as primary and eventually secondary sources are depleted.
    Environment International 06/2014; 71C:74-80. DOI:10.1016/j.envint.2014.05.019 · 5.66 Impact Factor
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    ABSTRACT: In images with low contrast-to-noise ratio (CNR), the information gain from the observed pixel values can be insufficient to distinguish foreground objects. A Bayesian approach to this problem is to incorporate prior information about the objects into a statistical model. This paper introduces a method for representing spatial prior information as an external field in a hidden Potts model of the image lattice. The prior distribution of the latent pixel labels is a mixture of Gaussian fields, centred on the positions of the objects at a previous point in time. This model is particularly applicable in longitudinal imaging studies, where the manual segmentation of one image can be used as a prior for automatic segmentation of subsequent images. The model is demonstrated by application to cone-beam computed tomography (CT), an imaging modality that exhibits distortions in pixel values due to X-ray scatter. The external field prior results in a substantial improvement in segmentation accuracy, reducing the mean pixel misclassification rate on our test images from 87% to 6%.
    Computational Statistics & Data Analysis 04/2014; 86. DOI:10.1016/j.csda.2014.12.001 · 1.15 Impact Factor
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    ABSTRACT: A decision-making framework for image-guided radiotherapy (IGRT) is being developed using a Bayesian Network (BN) to graphically describe, and probabilistically quantify, the many interacting factors that are involved in this complex clinical process. Outputs of the BN will provide decision-support for radiation therapists to assist them to make correct inferences relating to the likelihood of treatment delivery accuracy for a given image-guided set-up correction. The framework is being developed as a dynamic object-oriented BN, allowing for complex modelling with specific subregions, as well as representation of the sequential decision-making and belief updating associated with IGRT. A prototype graphic structure for the BN was developed by analysing IGRT practices at a local radiotherapy department and incorporating results obtained from a literature review. Clinical stakeholders reviewed the BN to validate its structure. The BN consists of a sub-network for evaluating the accuracy of IGRT practices and technology. The directed acyclic graph (DAG) contains nodes and directional arcs representing the causal relationship between the many interacting factors such as tumour site and its associated critical organs, technology and technique, and inter-user variability. The BN was extended to support on-line and off-line decision-making with respect to treatment plan compliance. Following conceptualisation of the framework, the BN will be quantified. It is anticipated that the finalised decision-making framework will provide a foundation to develop better decision-support strategies and automated correction algorithms for IGRT.
    Journal of Physics Conference Series 03/2014; 489:012074. DOI:10.1088/1742-6596/489/1/012074
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    ABSTRACT: Cone-beam computed tomography (CBCT) has enormous potential to improve the accuracy of treatment delivery in image-guided radiotherapy (IGRT). To assist radiotherapists in interpreting these images, we use a Bayesian statistical model to label each voxel according to its tissue type. The rich sources of prior information in IGRT are incorporated into a hidden Markov random field model of the 3D image lattice. Tissue densities in the reference CT scan are estimated using inverse regression and then rescaled to approximate the corresponding CBCT intensity values. The treatment planning contours are combined with published studies of physiological variability to produce a spatial prior distribution for changes in the size, shape and position of the tumour volume and organs at risk. The voxel labels are estimated using iterated conditional modes. The accuracy of the method has been evaluated using 27 CBCT scans of an electron density phantom. The mean voxel-wise misclassification rate was 6.2%, with Dice similarity coefficient of 0.73 for liver, muscle, breast and adipose tissue. By incorporating prior information, we are able to successfully segment CBCT images. This could be a viable approach for automated, online image analysis in radiotherapy.
    Journal of Physics Conference Series 02/2014; 489(1). DOI:10.1088/1742-6596/489/1/012076
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    ABSTRACT: Brominated flame retardants (BFRs), are chemicals widely used in consumer products including electronics, vehicles, plastics and textiles to reduce flammability. Experimental animal studies have confirmed that these compounds may interfere with thyroid hormone homeostasis and neurodevelopment but to date health effects in humans have not been systematically examined. To conduct a systematic review of studies on the health impacts of exposure to BFRs in humans, with a particular focus on children. A systematic review was conducted using the MEDLINE and EMBASE electronic databases up to 1 February 2012. Published cohort, cross-sectional, and case-control studies exploring the relationship between BFR exposure and various health outcomes were included. In total, 36 epidemiological studies meeting the pre-determined inclusion criteria were included. Plausible outcomes associated with BFR exposure include diabetes, neurobehavioral and developmental disorders, cancer, reproductive health effects and alteration in thyroid function. Evidence for a causal relationship between exposure to BFRs and health outcomes was evaluated within the Bradford Hill framework. Although there is suggestive evidence that exposure to BFRs is harmful to health, further epidemiological investigations particularly among children, and long-term monitoring and surveillance of chemical impacts on humans are required to confirm these relationships.
    Chemosphere 02/2014; 106. DOI:10.1016/j.chemosphere.2013.12.064 · 3.50 Impact Factor
  • IWA World Water Congress & Exhibition, Lisbon, Portugal; 01/2014
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    ABSTRACT: Introduction: Patients with virally mediated head and neck cancer (VMHNC) often present with advanced nodal disease that is highly radioresponsive as demonstrated by tumour and nodal regression during treatment. The resultant changes may impact on the planned dose distribution and so adversely affect the therapeutic ratio. The aim of this study was to evaluate the dosimetric effect of treatment-induced anatomical changes in VMHNC patients who had under-gone a replan. Methods: Thirteen patients with virally mediated oropharyngeal or nasopharyngeal cancer who presented for definitive radiotherapy between 2005 and 2010 and who had a replan generated were investigated. The dosimet-ric effect of anatomical changes was quantified by comparing dose–volume his-tograms (DVH) of primary and nodal gross target volumes and organs at risk (OAR), including spinal cord and parotid glands, from the original plan and a comparison plan. Results: Eleven three-dimensional conformal radiation ther-apy (3DCRT) and two intensity modulated radiation therapy (IMRT) plans were evaluated. Dose to the spinal cord and brainstem increased by 4.1% and 2.6%, respectively. Mean dose to the parotid glands also increased by 3.5%. In contrast, the dose received by 98% of the primary and nodal gross tumour vol-umes decreased by 0.15% and 0.3%, respectively, when comparing the initial treatment plan to the comparison plan. Conclusion: In this study, treatment-induced anatomical changes had the greatest impact on OAR dose with negligi-ble effect on the dose to nodal gross tumour volumes. In the era of IMRT, accounting for treatment-induced anatomical changes is important as focus is placed on minimizing the acute and long-term side effects of treatment.
    12/2013; 60(4):139-144. DOI:10.1002/jmrs.30
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    ABSTRACT: Objet Les cancers de la tête et du cou à médiation virale présentent souvent une participation ganglionnaire et sont fortement sensibles au rayonnement, de sorte qu’il faut adapter le plan de traitement en radiothérapie dans un sous-ensemble de patients. Nous avons cherché à déterminer les profils de risque potentiel et une stratégie de traitement adaptatif correspondante pour ces patients. Méthodologie Nous avons examiné les cas de 121 patients présentant un cancer à médiation virale avec participation ganglionnaire nasopharyngien (avec présence du virus Epstein-Barr) ou oropharyngien (papillomavirus) recevant une radiothérapie à but curatif. Le type, la fréquence et le moment des interventions adaptatives, y compris les corrections à la distance entre la source et la peau, le retraitement et les reprises de planification ont été évalués. Les patients ont fait l’objet d’une révision sur la base de la taille du ganglion dominant afin d’évaluer la nécessité d’une adaptation du plan de traitement. Résultats Le plan de traitement a dû être adapté en cours de traitement pour quarante-six patients (38%). La fraction médiane pour l’intervention d’adaptation a été de 26 pour la distance source-peau et de 22 pour les TMD de reprise de la planification. On a constaté une tendance vers trois groupes de profils de risque: 1) faible risque avec besoin minimal (<10%) d’intervention d’adaptation (taille pré-traitement du ganglion dominant ≤35 mm); 2) risque modéré avec besoin possible (<20%) d’intervention d’adaptation (taille pré-traitement du ganglion dominant de 36 à 45 mm); 3) risque élevé avec augmentation de la probabilité (>50%) de besoin d’intervention d’adaptation (taille pré-traitement du ganglion dominant ≥46 mm). Conclusion Dans cette étude, on a établi que les patients présentant un cancer de la tête ou du cou à médiation virale avec participation ganglionnaire et dont la taille maximum du ganglion dominant était >46 mm présentaient un risque plus élevé de nécessiter une nouvelle planification en cours de traitement de radiothérapie. Les conclusions seront mises à l’épreuve dans le cadre d’une prochaine étude prospective sur la radiothérapie adaptative.
    Journal of Medical Imaging and Radiation Sciences 09/2013; 44:135-141. DOI:10.1016/j.jmir.2013.04.001
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    ABSTRACT: Environmental and biological samples taken around Da Nang Air Base have shown elevated levels of dioxin over many years 1, 2, 3 . A pre-intervention knowledge, attitudes and practices (KAP) survey (2009), a risk reduction program (2010) and a post intervention KAP survey (2011) were undertaken in four wards surrounding Danang Airbase. A follow-up evaluation was undertaken in 2013. A KAP survey was implemented among 400 randomly selected food handlers. Eleven indepth interviews and four focus group discussions were also undertaken. The knowledge of respondents remained positive and/or improved at 2.5 years follow-up. There were no significant differences in attitudes toward preventing dioxin exposure across surveys; most respondents were positive in all three surveys. An increase in households (69.5%) undertaking measures to prevent exposure was observed, which was higher than in the pre-intervention survey (39.6%) and post-intervention survey (60.4%) (2 = 95.6; p < 0.001). The proportion of respondents practicing appropriate preventive measures was also significantly improved. Despite most of the intervention programÊs activities ceasing in 2010, the risk reduction program has resulted in positive outcomes over the longer-term, with many knowledge and attitude measures remaining stable or imporving. Some KAP indicators decreased, but these KAP indicators were still significantly higher than the pre-intervention levels. 2013 Vol. 1 Iss. 1 V i e t n a m J o u r n a l o f P u b l i c H e a l t h -w w w . v j p h . o r g 13 Tran Thi Tuyet Hanh et al.
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    ABSTRACT: The literature was reviewed to assess the relationship between the lipid adjusted concentration in human serum and breast milk (expressed as the serum/milk ratio) of a broad range of POPs in paired samples. Thirteen studies were identified, including seven studies that reported serum/milk ratios for polychlorinated dibenzo-dioxins and -furans (PCDD/Fs), ten for polychlorinated biphenyls (PCBs), five for polybrominated diphenyl ethers (PBDEs), and five for organochlorine pesticides (OCPs). Mean serum/milk ratios ranged between 0.7 and 25 depending on the compound and congener. For PCDD/Fs, PCBs and PBDEs, a clear trend of increasing mean serum/milk ratio by increasing molar volume, hydrophobicity and number of halogen substitutes was observed. The mean serum/milk ratios reported by the 13 studies summarized here will aid comparison between human POPs exposure studies using either serum or milk samples. More studies are needed to allow a valid comparison between data obtained from analysis of breast milk and serum samples for a broader range of POPs. Furthermore such studies may shed light on compound specific factors as well as other determinants that may affect the partitioning and partition kinetics of POPs between serum and breast milk.
    Chemosphere 08/2012; 89(8):911-8. DOI:10.1016/j.chemosphere.2012.06.049 · 3.50 Impact Factor
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    ABSTRACT: Brominated flame retardants, including hexabromocyclododecane (HBCD) and polybrominated diphenyl ethers (PBDEs) are used to reduce the flammability of a multitude of electrical and electronic products, textiles and foams. The use of selected PBDEs has ceased, however, use of decaBDE and HBCD continues. While elevated concentrations of PBDEs in humans have been observed in Australia, no data is available on other BFRs such as HBCD. This study aimed to provide background HBCD concentrations from a representative sample of the Australian population and to assess temporal trends of HBCD and compare with PBDE concentrations over a 16 year period. Samples of human milk collected in Australia from 1993 to 2009, primarily from primiparae mothers were combined into 12 pools from 1993 (2 pools); 2001; 2002/2003 (4 pools); 2003/2004; 2006; 2007/2008 (2 pools); and 2009. Concentrations of ∑HBCD ranged from not quantified (nq) to 19 ng g(-1)lipid while α-HBCD and γ-HBCD ranged from nq to 10 ng g(-1)lipid and nq to 9.2 ng g(-1)lipid. β-HBCD was detected in only one sample at 3.6 ng g(-1)lipid while ∑(4)PBDE ranged from 2.5 to 15.8 ng g(-1)lipid. No temporal trend was apparent in HBCD concentrations in human milk collected in Australia from 1993 to 2009. In comparison, PBDE concentrations in human milk show a peak around 2002/03 (mean ∑(4)PBDEs=9.6 ng g(-1)lipid) and 2003/04 (12.4 ng g(-1)lipid) followed by a decrease in 2007/08 (2.7 ng g(-1)lipid) and 2009 (2.6 ng g(-1)lipid). In human blood serum samples collected from the Australian population, PBDE concentrations did not vary greatly (p=0.441) from 2002/03 to 2008/09. Continued monitoring including both human milk and serum for HBCD and PBDEs is required to observe trends in human body burden of HBCD and PBDEs body burden following changes to usage.
    Chemosphere 06/2012; 89(4):398-403. DOI:10.1016/j.chemosphere.2012.05.053 · 3.50 Impact Factor

Publication Stats

741 Citations
90.77 Total Impact Points

Institutions

  • 2007–2015
    • Queensland University of Technology
      • • Institute of Health and Biomedical Innovation
      • • Discipline of Medical Radiation Sciences
      Brisbane, Queensland, Australia
  • 2004–2007
    • University of Queensland
      • National Research Centre for Environmental Toxicology
      Brisbane, Queensland, Australia