Karin English

Bisphenol A exposure pathways in early childhood: Reviewing the need for improved risk assessment models

Bisphenol A (BPA) is a plasticiser found in a number of household plastics, electronics, and food-packaging materials. Over the past 5 years, several human epidemiological studies have reported a positive association between BPA exposure and adverse health outcomes in children, including obesity, asthma, preterm birth, and neuro-behavioural disturbances. These findings are in conflict with international environmental risk assessment models, which predict daily exposure levels to BPA should not pose a risk to child health. The aim of this review is to provide an overview of the evidence for different exposure sources and potential exposure pathways of BPA in early childhood. By collating the findings from experimental models and exposure associations observed in human bio-monitoring studies, we affirm the potential for non-dietary sources to make a substantial contribution to total daily exposure in young children. Infants and toddlers have distinctive exposure sources, physiology, and metabolism of endocrine-disrupting chemicals. We recommend risk-assessment models implement new frameworks, which specifically address exposure and hazard in early childhood. This is particularly important for BPA, which is present in numerous products in the home and day-care environments, and for which animal studies report contradictory findings on its safety at environmentally relevant levels of exposure.

Organophosphate and brominated flame retardants in Australian indoor environments: Levels, sources, and preliminary assessment of human exposure

Concentrations of nine organophosphate flame retardants (OPFRs) and eight polybrominated diphenyl ethers (PBDEs) were measured in samples of indoor dust (n = 85) and air (n = 45) from Australian houses, offices, hotels, and transportation (buses, trains, and aircraft). All target compounds were detected in indoor dust and air samples. Median ∑9OPFRs concentrations were 40 μg/g in dust and 44 ng/m3 in indoor air, while median ∑8PBDEs concentrations were 2.1 μg/g and 0.049 ng/m3. Concentrations of FRs were higher in rooms that contained carpet, air conditioners, and various electronic items. Estimated daily intakes in adults are 14000 pg/kg body weight/day and 330 pg/kg body weight/day for ∑9OPFRs and ∑8PBDEs, respectively. Our results suggest that for the volatile FRs such as tris(2-chloroethyl) phosphate (TCEP) and TCIPP, inhalation is expected to be the more important intake pathway compared to dust ingestion and dermal contact.

BDE-209 in the Australian Environment: Desktop review

The commercial polybrominated diphenyl ether (PBDE) flame retardant mixture c-decaBDE is now being considered for listing on the Stockholm Convention on Persistent Organic Pollutants. The aim of our study was to review the literature regarding the use and detection of BDE-209, a major component of c-decaBDE, in consumer products and provide a best estimate of goods that are likely to contain BDE-209 in Australia. This review is part of a larger study, which will include quantitative testing of items to assess for BDE-209. The findings of this desktop review will be used to determine which items should be prioritized for quantitative testing. We identified that electronics, particularly televisions, computers, small household appliances and power boards, were the items that were most likely to contain BDE-209 in Australia. Further testing of these items should include items of various ages. Several other items were identified as high priority for future testing, including transport vehicles, building materials and textiles in non-domestic settings. The findings from this study will aid in the development of appropriate policies, should listing of c-decaBDE on the Stockholm Convention and Australias ratification of that listing proceed.

Concentrations of organophosphate flame retardants and plasticizers in urine from young children in Queensland, Australia and associations with environmental and behavioural factors

&NA; In recent years, the production and usage volumes of organophosphate flame retardants (OPFRs) has increased substantially. Certain OPFRs are suspected reproductive toxins, carcinogenic, and neurotoxic. Insufficient information is available on human exposure pathways to these chemicals, particularly in Australia. We aim to assess the association between OPFR concentrations in the urine of children to environmental and behavioural risk factors. Concentrations of eight OPFRs and eleven metabolites were measured in the urine of 51 children, aged 3–29 months, in Southeast Queensland, Australia and compared to their behavioural and environmental risk factor data obtained by an online questionnaire. Of the 11 OPFR metabolites analysed, 55% were frequently detected in the majority (> 80%) of samples. The most frequently detected metabolite was bis(1,3‐dichloroisopropyl) phosphate (BDCIPP) (detected in 100% of samples), followed by 1‐hydroxy‐2‐propyl bis(1‐chloro‐2‐propyl) phosphate (BCIPHIPP) (96%), diphenyl phosphate (DPHP) (94%) and bis(1‐chloroisopropyl) phosphate (BCIPP) (86%). In multivariable modelling, age was positively associated with concentrations of bis(2‐butoxyethyl) phosphate (BBOEP) and negatively associated with concentrations of BCIPP and BCIPHIPP. Other non‐age related factors, including vacuuming frequency, hand‐washing frequency and presence and number of some electrical appliances in the home were also associated with concentrations of OPFR metabolites. HighlightsEight OPFRs and eleven metabolites were measured in the urine of Australian kids.Age was positively associated with BBOEP and negatively associated with BCIPP.Mouthing activities were associated with higher concentrations of TBOEP, and TPHP.Children living with window AC units had higher concentrations of BCIPHIPP and DBP.

Polybrominated diphenyl ether flame retardant concentrations in faeces from young children in Queensland, Australia and associations with environmental and behavioural factors

Abstract The aim of our study was to investigate childrens exposure to the flame retardants polybrominated diphenyl ethers (PBDEs) by analysing faecal content, a non‐invasive matrix, as well as responses to an exposure‐assessment questionnaire. A convenience sample of 61 parents with children (aged >3 months to <2 years) completed an online pre‐tested questionnaire and provided faecal samples for analysis by high resolution gas chromatography/mass spectrometry. BDE‐209 was the dominant congener in faecal samples adjusted to 8.3 ng/g dry weight (dw), with >80% samples above the limit of detection (LOD). BDE‐47 (0.23 ng/g dw) and BDE‐153 (0.03 ng/g dw) were each detected above the LOD in approximately 60% of samples. Age was associated with BDE‐47 (−7%/month) and BDE‐153 (−12%/month) concentrations in faeces, but not BDE‐209. Other variables associated with PBDE concentrations included features of the home (carpet, pets) and behaviour (hand‐to‐mouth, removing shoes, using a car sunshade, frequency of walks outdoors). However, given the small sample size of this study additional research is required to confirm these findings. In this study we demonstrated that faeces may be a viable alternative to monitor human exposure to PBDEs, but further validation studies are required. HighlightsThis study provides the first report of BDE‐209 biomonitoring in Australian children.Faeces, a non‐invasive matrix, were used to assess PBDE exposure in young children (<2 years) exposure.BDE‐47 and BDE‐153 but not BDE‐209 concentrations were significantly negatively associated with childs age age.Faeces may be a viable alternative to serum for biomonitoring, but more validation studies are required.

Unintentional insecticide poisoning by age: an analysis of Queensland Poisons Information Centre calls.

Objective: Data from the Queensland Poisons Information Centre (QPIC) was assessed to determine mechanisms of acute insecticide poisoning in young children (<5 years) and whether age affects insecticide‐poisoning patterns.

Assessing exposure of young children to common endocrine-disrupting chemicals in the home environment: A review and commentary of the questionnaire-based approach

Abstract Background: Although infants and young children are particularly vulnerable to endocrine disrupting chemical (EDC) exposure, there is an absence of comprehensive exposure data for this age group. As young children spend the majority of their time indoors, improved methods of exposure assessment are needed to characterise the health risks from exposures in the home environment. Biologic assessment, which has been considered the gold standard for exposure assessment in recent years, is difficult to conduct in young children. Questionnaires are an alternative and indirect method of predicting exposure, which may overcome some of the limitations of direct exposure assessment. Research problem: The feasibility of using a questionnaire-based approach to predict exposure of young children to EDCs in the home has yet to be comprehensively reviewed. Moreover, there is no one questionnaire that has been validated for predicting the exposure of infants to common EDCs in the home. Aims and objectives: The aim of this review is to discuss the use and validation of the questionnaire-based approach to predict exposure of children to chemicals from three common classes of EDCs in the home, namely, plasticisers, flame retardants, and insecticides. We discuss the strengths and weaknesses of the questionnaire-based approach as well as the important pathways of exposure in the home environment, by which to guide the design and validation of future exposure questionnaires. Results: The findings from our review indicate that the questionnaire-based approach is a valuable tool in the prediction of exposure to persistent organic pollutants, as well as to toxicants that have consistent patterns of exposure. With improvements to the design and validation process, the questionnaire-based approach may also prove to be a reliable instrument in predicting exposure to EDCs with short-half lives, including bisphenol A, phthalates, and pyrethroid and organophosphate insecticides.

A case report of plasticizer exposure and asthmatic symptoms during pregnancy

Aim: The development of fibrosis in Idiopathic Pulmonary Fibrosis (IPF) is a key feature and challenge in the treatment of the disease. The mechanisms of collagen I (COL1) reorganisation in the development of fibrosis, which may alter the stiffness of the tissue, are not well understood. Fibrillar COL1 has second harmonic generation (SHG) properties. SHG signals are coherent, propagating both in the forward (F) (primarily organized/mature collagen) and backward (B) (primarily disorganized/immature collagen) directions relative to the incident light. Collagen fibre maturity is governed by the degree of crosslinking and catalysed by enzymes from the Lysyl Oxidase family (LOX, LOXL1- 4), which are implicated IPF pathology. The aim of this study was to investigate collagen I structural remodelling and the pathological role of Lysyl Oxidases in the development of fibrosis in IPF. Methods: Formalin-fixed-and-paraffin-embedded parenchymal tissues from non-diseased donors (n = 8) and IPF explanted lungs (n = 8) were analysed for SHG. F/B SHG signal ratio was used to determine the proportion of organized to disorganized collagen. Immunohistochemistry detected LOX and LOXL1 levels in tissues with single-blinded analysis to quantify colorimetric staining by computer-assisted image-analysis. Results: Increased F/B ratio was observed in IPF compared to non-diseased tissues (p = 0.034) indicating increased COL1 fibre maturity in IPF. There was decreased LOX (p = 0.009) and increased LOXL1 (p = 0.031) expression in IPF. In lung tissues LOX negatively correlated with F/B ratio (p = 0.0491, r2= 0.249, n = 16), while LOXL1 positively correlated with F/B ratio (p = 0.003, r2= 0.4898, n = 16). Conclusion: Increased levels of COL1 fibre maturity in IPF could contribute to the increased stiffness of the tissue. LOXL1, but not LOX, may regulate the increased collagen fibre maturity in IPF tissues. These findings indicate there may be a specific role for LOX family members in the development of fibrosis in IPF.