Phthalates: Relationships between Air, Dust, Electronic Devices, and Hands with Implications for Exposure.

Exposure to phthalates is pervasive and is of concern due to associations with adverse health effects. Exposures and exposure pathways of six phthalates were investigated for 51 women aged 18-44 years in Ontario, Canada, based on measured phthalate concentrations in hand wipes and indoor media in their residences. All six phthalates had detection frequencies of 100% in air (∑6670 ng m-3 geomean) and floor dust (∑6630 µg g-1), nearly 100% detection frequencies for hand palms and backs that were significantly correlated and concentrations were repeatable over a 3 week interval. Phthalates on hands were significantly correlated with levels in air and dust, as expected according to partitioning theory. Total exposure was estimated as 4860 ng kg bw-1 day-1 (5th and 95th percentiles 1980-16 950 ng kg bw-1 day-1), with dust ingestion, followed by hand-to-mouth transfer, as the dominant pathways. With the exception of diethyl phthalate (DEP), phthalates had over 50% detection frequencies in surface wipes of most electronic devices sampled, including devices in which the use of phthalates was not expected. Phthalate concentrations on surfaces of hand-held devices were ∼10 times higher than on non-hand-held devices and were correlated with levels on hands. The data are consistent with phthalate emissions from sources such as laminate flooring and personal care products (e.g., scented candles), followed by partitioning among air, dust, and surface films that accumulate on electronic devices and skin, including hands. We hypothesize that hands transfer phthalates from emission sources and dust to hand-held electronic devices, which accumulate phthalates due to infrequent washing and which act as a sink and then a secondary source of exposure. The findings support those of others that exposure can be mitigated by increasing ventilation, damp cloth cleaning, and minimizing the use of phthalate-containing products and materials.

Are cell phones an indicator of personal exposure to organophosphate flame retardants and plasticizers?

BACKGROUND: Exposure to organophosphate ester (OPE) flame retardants and plasticizers is widespread and is of concern due to their toxicity. OBJECTIVES: To investigate relationships between and within OPE concentrations in air, dust, hands, electronic product wipes and urinary metabolites with the goal of identifying product sources and exposure pathways. METHODS: Women in Toronto and Ottawa, Canada, provided a urine sample, two sets of hand wipes, access to their homes for air and dust sampling, and completed a questionnaire. OPE concentrations were obtained for air and floor dust in the bedroom (n = 51) and most used room (n = 26), hand wipes (n = 204), and surface wipes of handheld (n = 74) and non-handheld electronic devices (n = 125). All air, dust and wipe samples were analyzed for 23 OPE compounds; urine samples (n = 44) were analyzed for 8 OPE metabolites. RESULTS: Five-8 OPEs were detected in >80% of samples depending on the sample type. OPE median concentrations in hand wipes taken 3 weeks apart were not significantly different. Palms had higher concentrations than the back of hands; both were significantly correlated. Concentrations of 9 OPEs were significantly higher in surface wipes of handheld than non-handheld electronic devices. Six OPEs in hand wipes were significantly correlated with cell phone wipes, with two to four OPEs significantly correlated with tablet, laptop and television wipes. Multiple regression models using hand wipes, cell phone wipes and dust explained 8-33% of the variation in creatinine-adjusted urinary metabolites; air concentrations did not have explanatory power. OPEs in cell phone wipes explained the greatest variation in urinary metabolites. CONCLUSIONS: Handheld electronic devices, notably cell phones, may either be sources or indicators of OPE exposure through hand-to-mouth and/or dermal uptake.

Trends in hexabromocyclododecanes in the UK and North America.

Water samples (n = 107) taken from nine English freshwater lakes from a mix of urban, rural, and remote locations on 12 occasions between August 2008 and February 2012, and archived suspended sediment samples (n = 39) collected over the period 1980-2012 at the mouth of the Niagara River in Lake Ontario were analysed to assess the temporal trends in contamination by the three main hexabromocyclododecane (HBCD) diastereomers (α-, ß-, and γ-HBCD). HBCDs (45 to 890 pg L-1, n = 107) were generally equally distributed between the operationally defined freely dissolved and particulate phases in English lake water. Concentrations of HBCDs declined over the sampling period with half-lives of 5.1 years in English water, with a significantly decreasing trend also observed for Niagara River suspended sediments (NRSSs). With respect to seasonal trends, significantly higher concentrations were found in colder compared to warmer periods at 5 out of 9 English lakes, while NRSSs in this study revealed no statistically significant seasonal trends. The maximum HBCD concentration in NRSSs was about 3 orders of magnitude lower than those detected in English lake water, which is plausible given the greater per capita use of HBCD in Europe than North America. While γ-HBCD was consistently dominant (35-86%; mean = 56%) in English lake water samples, and dominated in NRSSs collected prior to 2002 inclusive (13-100%, mean = 73%), the abundance of γ-HBCD was significantly lower (3.5-37%; mean = 23%) in NRSSs from 2003 onwards.

Passive air sampling of flame retardants and plasticizers in Canadian homes using PDMS, XAD-coated PDMS and PUF samplers.

Passive air samplers (PAS) were evaluated for measuring indoor concentrations of phthalates, novel brominated flame retardants (N-BFRs), polybrominated diphenyl ethers (PBDEs), and organophosphate esters (OPEs). Sampling rates were obtained from a 50-day calibration study for two newly introduced PAS, polydimethylsiloxane (PDMS) or silicone rubber PAS (one with and one without a coating of styrene divinyl benzene co-polymer, XAD) and the commonly used polyurethane foam (PUF) PAS. Average sampling rates normalized to PAS surface area were 1.5 ±â€¯1.1 m3 day-1 dm-2 for both unsheltered PDMS and XAD-PDMS, and 0.90 m3 ±â€¯0.6 day-1dm-2 for partially sheltered PUF. These values were derived based on the compound-specific sampling rates measured here and in the literature for the PAS tested, to reasonably account for site-specific variability of sampling rates. PDMS and PUF were co-deployed for three weeks in 51 homes located in Ottawa and Toronto, Canada. Duplicate PUF and PDMS samplers gave concentrations within 10% of each other. PDMS and PUF-derived air concentrations were not statistically different for gas-phase compounds. PUF had a higher detection of particle-phase compounds such as some OPEs. Phthalate and OPE air concentrations were ∼100 times higher than those of N-BFRs and PBDEs. Concentrations were not systematically related to PM10, temperature or relative humidity. We conclude that both PAS provide replicable estimates of indoor concentrations of these targeted semi-volatile organic compounds (SVOCs) over a three-week deployment period. However, PUF is advantageous for collecting a wider range of compounds including those in the particle phase.

Palaeotoxicity: reconstructing the risk of multiple sedimentary pollutants to freshwater organisms.

'Real-world' contaminant exposure of sediment-dwelling biota is typically long-term, low-level and to multiple pollutants. However, sediment quality guidelines, designed to protect these organisms, relate only to single contaminants. This study uses radiometrically dated sediment cores from 7 English lakes with varying contamination histories to reconstruct temporal changes in likely risk to biota (herein termed 'palaeotoxicity'). The Probable Effects Concentration Quotient (PEC-Q) approach was used to combine sediment concentrations from multiple contaminants (trace metals; PCBs; PBDEs) to determine risk allocated to metals and persistent organic pollutants (POPs) separately as well as combined (PEC-Q Mean-All). Urban-influenced lakes were considerably more contaminated, exceeding PEC-Q thresholds of 0.5 and 2.0 over long durations (some since the nineteenth century). This has been mainly due to metals (principally lead) and by factors of up to 10 for individual metals and by > 2 for PEC-Q Mean-Metals. In 6 out of 7 lakes, considerable reductions in risk associated with trace metals are observed since emissions reductions in the 1970s. However, at all lakes, PEC-Q Mean-POPs has increased sharply since the 1950s and at 5 out of 7 lakes now exceeds PEC-Q Mean-Metals. These organic pollutants are therefore now the dominant driver behind elevated contaminant risk to sediment-dwelling biota and recent temporal trends in PEC-Q Mean-All remain above threshold values as a result. Finally, PEC-Q Mean-All values were compared to standard biological toxicity tests for surface sediments at each site. While chironomid growth and daphniid reproduction were significantly reduced compared to controls at 5 out of 7, and all lakes, respectively, the scale of these reductions showed only limited quantitative agreement with predicted risk.

Hexabromocyclododecanes, polybrominated diphenyl ethers, and polychlorinated biphenyls in radiometrically dated sediment cores from English lakes, ~1950-present.

This paper reports input fluxes between ~1950 and present, of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and hexabromocyclododecanes (HBCDs) in radiometrically-dated sediment cores from 7 English lakes. Fluxes of PCBs at all but one location prone to significant sediment resuspension peaked in the late-1960s/early-1990s, before declining thereafter. Input fluxes of HBCDs at all sites increased from first emergence in the mid-1960s. Thereafter, fluxes peaked in the late-1980s/early-2000s, before declining through to the present, except at the most urban site where HBCD fluxes are still increasing. Trends of PBDEs predominant in the Penta-BDE and Octa-BDE formulations vary between sites. While at some locations, fluxes peaked in the late-1990s/early-2000s; at others, fluxes are still increasing. This suggests the full impact of EU restrictions on these formulations has yet to be felt. Fluxes of BDE-209 have yet to peak at all except one location, suggesting little discernible environmental response to recent EU restrictions on the Deca-BDE product. Strikingly, fluxes of BDE-209 in the most recent core slices either exceed or approach peak fluxes of ΣPCBs, implying substantial UK use of Deca-BDE. Excepting HBCDs, inventories of our target contaminants correlated significantly with local population density, implying substantial urban sources.

Polybrominated diphenyl ethers (PBDEs) in English freshwater lakes, 2008-2012.

Concentrations of tri-to-hexa-BDEs were determined in water samples taken from 9 English lakes on 13 occasions between April 2008 and February 2012. Across all sites, concentrations of ΣBDEs in individual samples ranged from 9.2 to 171.5pgL(-)(1), with an average of 61.9pgL(-)(1). Notwithstanding the far greater use of the Penta-BDE commercial formulation in the USA, concentrations in this study are comparable to the limited data available for the Great Lakes. PBDE concentrations showed no evidence of a decline at any monitored location over the study period. This may be because this study commenced 4years after the introduction of restrictions on the Penta- and Octa-BDE formulations. While concentrations normalised to water volume at the different locations were statistically indistinguishable; significant spatial variation was apparent when the data were normalised to total suspended solids (TSS) content. However, this spatial variation was not correlated with factors such as population density and lake catchment area, suggesting that concentrations of PBDEs in lake water in this study are a complex integral of numerous factors. BDE-47:99 ratios and concentrations of ΣBDEs respectively decreased and increased significantly with increasing TSS content. As TSS content was elevated in colder compared with warmer periods, such seasonal variation in TSS content appears a major contributor to the observed elevation of ΣBDE concentrations in colder periods, and higher BDE-47:99 ratios in warmer periods.

[Correlations between HBCD and thyroid hormone concentrations in human serum from production source area].

The levels of hexabromocyclododecane (HBCD) in human serum from the HBCD production source region were detected by UPLC-ESI-MS/MS. The concentrations (lipid weight) of ∑ HBCD in 80 serum samples ranged from not detectable to 2702.5 ng · g(-1). The mean and median values were 104.9 ng · g(-1) and 5.9 ng · g(-1), respectively. The most abundant HBCD isomer in 42 samples was γ-HBCD, while α-HBCD was the most abundant isomer in the other 26 serum samples. There was no significant difference in ∑ HBCD concentration among different age and gender. In this study, the thyroid hormone abnormality rate in the 80 residents was up to 33%. The thyroid hormone abnormality rate of the residents whose serum HBCD was detected was significantly higher than those without HBCD in serum. Since the local residents were highly exposed to HBCD, the probability of thyroid abnormality might be significantly increased.

Polybrominated diphenyl ethers in atmosphere and soil of a production area in China: levels and partitioning.

Polybrominated diphenyl ethers (PBDEs) were measured in atmosphere and soil samples taken in winter and summer at a PBDE production area of Laizhou Bay in China. The concentrations of Sigma11PBDE were 0.017-1.17 ng/m3 in gaseous phase, 0.5-161.1 ng/m3 in particulate phase, and 73-2629 ng/g dry weight in soil samples. The PBDE congener pattern in the gaseous phase differed from that in the particulate phase, and the PBDE congener pattern in the particulate phase was similar with that in soil. This demonstrated that there was little difference with atmospheric particle-soil transfer efficiency among PBDE congeners. In addition, there were seasonal variations in percentages on particle for lower brominated congeners. The BDE-28 was mostly in the gaseous phase in summer (88.3%), whereas the average proportion of BDE-28 in gaseous phase in winter was 38.9%. Higher brominated congeners (i.e., BDE-206, BDE-207, BDE-208, and BDE-209) were bound to the atmospheric particulate phase, and their potentials for long-range migration were mainly affected by the environmental behavior of atmospheric particles. Results indicated that PBDE congeners in summer were closer to gas-particle partition equilibrium than in winter. Temperature should be considered the main factor causing nonequilibrium in winter.

[Correlations between PBDEs and thyroid hormone concentrations in adults from production source area].

Polybrominated diphenyl ethers (PBDEs) concentrations in 36 resident serum samples from PBDEs production source area were analyzed by gas chromatography/negative chemical ionization/mass spectrometry(GC-NCI-MS) method, and the concentrations of thyroid hormones were determined as well. The sigma5PBDEs (BDE-28, -47, -153, -183, -209) concentrations(lipid weight) in serum ranged from 130.3 to 4 478.4 ng x g(-1), with an average value of 529.9 ng x g(-1). BDE-209 was a dominant PBDE congener, on average accounting for 69.8% of the total PBDEs concentrations. Spearman rank correlation coefficient was calculated between PBDEs and thyroid hormone, it showed that there were high significant negative correlation between BDE-28, -47, -153, -183 and thyroid-stimulating hormone (TSH), and significant negative correlation was also found between BDE-183 and free thyroxine (fT4). Additionally, there were significant positive correlation between BDE-28, -47 and triiodothyronine (T3), as well as between BDE-28, -153, -183 and free triiodothyronine(fT3). In summary, the concentrations of PBDEs in serum in this study were at a high level, and BDE-209 was the predominant congener. The exposure to the PBDEs may affect thyroid hormone levels, and the further research should focus on the relationship between PBDEs and thyroid hormone concentrations.

Human exposure to polybrominated diphenyl ethers at production area, China.

The concentrations of polybrominated diphenyl ethers (PBDEs) were detected in air and aquatic products in PBDEs production areas which are located at the south coast area of Laizhou Bay, Shandong province, China in this study. Concentrations of SigmaPBDEs in the air ranged from 0.47 ng/m3 to 161 ng/m3. In aquatic products, concentrations of SigmaPBDEs ranged from 2.7 ng/g wet weight to 42 ng/g wet weight. The mean dietary intake of SigmaPBDEs via aquatic products consumption in this study was 218 ng/day. Daily intake of SigmaPBDEs via inhalation in this study was 612 ng for men and 455 ng for women. With a contribution of 80%, BDE-209 was predominant in the total intake. Dietary intake and breathing inhalation contributed 29 and 71%, respectively, to the total PBDEs intake. The results indicate that breathing inhalation also plays a very significant pathway for the population of the PBDEs production area. Compared with similar studies in other countries, human exposure to PBDEs via diet and inhalation in this study was the highest in the world.

Polybrominated diphenyl ethers in the serum and breast milk of the resident population from production area, China.

Polybrominated diphenyl ethers (PBDEs) have been produced in the south coast area of Laizhou Bay, Shandong Province in China, but little is known about the PBDE exposure level of residents to these compounds. We set out to assess potential health risks of PBDEs in the south coast area of the Laizhou Bay by determining the concentrations of PBDEs in serum and breast milk. We measured concentrations of eight PBDE congeners in serum and breast milk. The arithmetic means of Sigma(8)PBDE in pooled serum and breast milk were 613 ng/g lipid and 81.5 ng/g lipid, respectively. The highest concentration for Sigma(8)PBDE in all serum pools was 1830 ng/g lipid from the 41-50 year old female group. BDE-209 was the predominant congener, with the mean concentrations of 403 ng/g lipid in serum and 45.6 ng/g lipid in breast milk, respectively. BDE-209 averagely accounted for 65.8% and 54.2% of the total PBDEs, respectively. Our results suggest that high exposures to PBDEs have led to very high PBDE concentrations in serum and breast milk from the residents living in the south coast area of Laizhou Bay. High PBDE concentrations in human serum, particularly in women, pose a potential public health threat to local residents.