Selective determination of organophosphate flame retardants and plasticizers in indoor air by gas chromatography, positive-ion chemical ionization and collision-induced dissociation mass spectrometry

Organophosphate triesters and their diester degradation products in the atmosphere-A critical review

Organophosphate triesters (tri-OPEs) have found substantial use as plasticizers and flame retardants in commercial and industrial products. Despite upcoming potential restrictions on use of OPEs, widespread environmental contamination is likely for the foreseeable future. Organophosphate diesters (di-OPEs) are known biotic or abiotic degradation products of tri-OPEs. In addition, direct use of di-OPEs as commercial products also contributes to their presence in the atmosphere. We review the available data on contamination with tri-OPEs and di-OPEs in both indoor and outdoor air. Concentrations of tri-OPEs in indoor air exceed those in outdoor air. The widespread discovery of tri-OPE traces in polar regions and oceans is noteworthy and is evidence that they undergo long-range transport. There are only two studies on di-OPEs in outdoor air and no studies on di-OPEs in indoor air until now. Current research on di-OPEs in indoor and outdoor air is urgently needed, especially in countries with potentially high exposure to di-OPEs such as the UK and the US. Di-OPE concentrations are higher at e-waste dismantling areas than at surrounding area. We also summarise the methods employed for sampling and analysis of OPEs in the atmosphere and assess the relative contribution to atmospheric concentrations of di-OPEs made by environmental degradation of triesters, compared to the presence of diesters as by-products in commercial triester products. Finally, we identify shortcomings of current research and provide suggestions for future research.

A critical review on organophosphate esters in drinking water: Analysis, occurrence, sources, and human health risk assessment

Organophosphate esters (OPEs) are ubiquitous in the environment. Copious studies assessed OPEs in various environmental media. However, there is limited summative information about OPEs in drinking water. This review provides comprehensive data for the analytical methods, occurrence, sources, and risk assessment of OPEs in drinking water. In general, liquid-liquid extraction and solid-phase extraction are the most common methods in the extraction of OPEs from drinking water, while gas chromatography and liquid chromatography are the most commonly used instrumental methods for detecting OPEs in drinking water. On the basis of these techniques, a variety of methods on OPEs pretreatment and determination have been developed to know the pollution situation of OPEs. Studies on the occurrence of OPEs in drinking water show that the total concentrations of OPEs vary seasonally and regionally, with tris(1-chloro-2-isopropyl) phosphate and tris(2-chloroethyl) phosphate dominant among different kinds of drinking water. Source identification studies show that there are three main sources of OPEs in drinking water: 1) source water contamination; 2) residual in drinking water treatment process; 3) leakage from device or pipeline. Besides, risk assessments indicate that individual and total OPEs pose no or negligible health risk to human, but this result may be significantly underestimated. Finally, the current knowledge gaps on the research of OPEs in drinking water are discussed and some suggestions are provided for future environmental research.

Cytotoxic and genotoxic effects of triphenyl phosphate on root tip cells of Allium cepa L

Triphenyl phosphate (TPhP) is a tri-ester of phosphoric acid and phenol. It is used in products such as polyvinyl chloride, hydraulic fluids, polymers, photographic films and printed circuit cards as a flame retardant. It is also widely used in consumer products like electric and electronic devices, textiles and building necessaries. TPhP can diffuse into its surrounding environment easily, because it does not form a chemical bond with polymeric materials. Therefore, bio-monitoring of such compounds is needed for possible environmental and human health effects. In this study, we evaluated genotoxicity and cytotoxicity of TPhP on Allium cepa on the cells of root tips. A 10 mg/mL stock solution of TPhP was dissolved in DMSO and dilutions of 2, 4, 6, 8 and 10 mg/mL was made in distilled water. Onion bulbs, rooted in test tubes, were exposed to these concentrations of TPhP for 24 h. Distilled water was used as a negative control, 0.7% hydrogen peroxide was used as positive control, and 0.5% DMSO was used as solvent control. Significant inhibition of onion root growth was observed following treatment with the 6, 8 and 10 mg/mL TPhP ranges in comparison with the negative and solvent control groups (p < 0.05). Furthermore, in the TPhP treatment groups, total chromosome aberration ratios were significantly high in comparison with the controls (p < 0.05). These results suggest that TPhP have cytotoxic and genotoxic effects on A. cepa root tips.

Organophosphate esters (OPEs) and novel brominated flame retardants (NBFRs) in indoor dust: A systematic review on concentration, spatial distribution, sources, and human exposure

In recent years, the indoor exposure of organophosphate esters (OPEs) and novel brominated flame retardants (NBFRs) has received widespread attention worldwide. Using published data on 6 OPEs in 23 countries (n = 1437) and 2 NBFRs in 18 countries (n = 826) in indoor dust, this study systematically reviewed the concentrations, spatial distribution, sources and exposure risk of 8 flame retardants (FRs) worldwide. Tris(chloroisopropyl)phosphate (TCIPP) is the predominant FR with a median concentration of 1050 ng g-1 ΣCl-OPEs are significantly higher than Σnon-Cl-OPEs (p < 0.05). ΣOPEs in indoor dust from industrially-developed countries are higher than those from the countries lacking industrial development. Household appliances, electronics and plastic products are the main sources of non-Cl-OPEs and NBFRs, while interior decorations and materials contribute abundant Cl-OPEs in indoor dust. The mean hazard index (HI) of TCIPP for children is greater than 1, possibly posing non-cancer risk for children in some countries. The median ILCRs for 3 carcinogenic OPEs are all less than 10-6, suggesting no cancer risk induced by these compounds for both adults and children. This review helps to understand the composition, spatial pattern and human exposure risk of OPEs and NBFRs in indoor dust worldwide.

Direct evidence of the important role of proteins in bioconcentration and biomagnification of PFASs in benthic organisms based on comparison with OPEs

Despite the wide acceptance that bioconcentration and biomagnification of per/polyfluoroalkyl substances (PFASs) is related to proteins in organisms, few direct evidences are available. Here, bioconcentration and biomagnification of 9 organophosphate esters (OPEs) and 16 PFASs, which have similar range of log K_ow (octanol-water partitioning coefficient) values, were compared in the benthic food chain of biofilm-snail in Taihu Lake, China. The ∑OPEs level in water (150-23,036 ng/L) was significantly higher than ∑PFASs (57.3-351 ng/L). Although the logarithm of bioconcentration factors of both OPEs and PFASs in biofilm positively correlated with their log K_ow, the slope of PFASs was 4 times of that of OPEs, which might be due to the strong interactions of PFASs with biofilm extracellular proteins. Additionally, PFASs exhibited distinctly greater biomagnification factors from biofilm to snails (3.09-17.8) than OPEs (0.39-3.48). Significant correlations between the concentrations and protein contents in snails were observed for most long-chain PFASs, but not for any OPEs. Multiple receptor models identified polyurethane foam (77.9 %) and food packaging/metal plating (56.9 %) were the primary sources of OPEs and PFASs in Taihu Lake, respectively. We provided strong and direct evidences that proteins facilitated bioconcentration and biomagnification of PFASs.

A scalable field study using leaves as a novel passive air sampler to evaluate the potential source of organophosphate esters in street dust

Organophosphate esters (OPEs) are widely used as flame retardants and plasticizers in industrial and commercial products. It is generally believed that OPEs in street dust mainly originate from road traffic and anthropogenic activities. The influence of atmospheric deposition is still unknown. In this study, leaves were employed as a novel passive air sampler to collect particle matters (PM) in 12 cities in the central province of Henan, China. Similar compositional profiles of OPEs were found in street dust and PM samples. The concentrations of individual OPEs in PM were 1-4 times higher than in street dust. Chlorinated OPEs concentration in PM shows a moderate correlation (r² = 0.538, p < 0.01) with that in street dust. The concentration of alkyl OPEs in PM has a high correlation (r² = 0.843, p < 0.01) with that in street dust. No significant correlation (r² = 0.133, p = 0.132) was found on the aryl OPEs concentrations between street dust and PM. Spearman correlation reveals that the emission sources of tricresyl phosphate (TCrP) and triethyl phosphate (TEP) may be different from other OPEs in dust and PM samples. Principle component analysis (PCA) provides an appropriate explanation that tris (2-chloroethyl) phosphate (TCEP), triphenyl phosphate (TPhP), tris (chloropropyl) phosphate (TCPP), tributyl phosphate (TnBP), and TEP in street dust and PM may be emitted from the same sources, suggesting that PM has a significant influence on the occurrence of OPEs in street dust. The estimated dry deposition fluxes of particle-bound OPEs show a significant correlation (R² = 0.969, p < 0.01) with OPEs concentrations in street dust, revealing that the input of atmospheric deposition could be a major source of OPEs in street dust.

Comprehensive characterization of halogenated flame retardants and organophosphate esters in settled dust from informal e-waste and end-of-life vehicle processing sites in Vietnam: Occurrence, source estimation, and risk assessment

Information about the co-occurrence of halogenated flame retardants (HFRs) and organophosphate esters (OPEs) in the environment of informal waste processing areas is still limited, especially in emerging and developing countries. In this study, OPEs and HFRs including polybrominated diphenyl ethers (PBDEs), novel brominated flame retardants (NBFRs), and chlorinated flame retardants (CFRs) were determined in settled dust from Vietnamese e-waste recycling (WR) and vehicle processing (VP) workshops. Pollutant concentrations decreased in the order: OPEs (median 1500; range 230-410,000 ng/g) ≈ PBDEs (1200; 58-250,000) > NBFRs (140; not detected - 250,000) > CFRs (13; 0.39-2200). HFR and OPE levels in the WR workshops for e-waste and obsolete plastic were significantly higher than in the VP workshops. Decabromodiphenyl ether and decabromodiphenyl ethane are major HFRs, accounting for 60 ± 26% and 25 ± 29% of total HFRs, respectively. Triphenyl phosphate, tris(2-chloroisopropyl) phosphate, and tris(1,3-dichloroisopropyl) phosphate dominated the OPE profiles, accounting for 30 ± 25%, 25 ± 16%, and 24 ± 18% of total OPEs, respectively. The OPE profiles differed between WR and VP dust samples, implying different usage patterns of these substances in polymer materials for electric/electronic appliance and automotive industries. Human health risk related to dust-bound HFRs and OPEs in the study areas was low.

Atmospheric deposition, seasonal variation, and long-range transport of organophosphate esters on Yongxing Island, South China Sea

The South China Sea (SCS), surrounded by developing countries/regions with a huge consumption of flame retardants, is generally contaminated by organophosphate esters (OPEs). However, studies on the occurrence, deposition and long-range atmospheric transport (LRAT) process over the SCS of OPEs compounds are still limited. In this work, 10 OPEs were measured in 100 atmospheric samples collected from Yongxing Island (YXI) in the SCS. The total OPEs concentrations ranged from 1508 to 1968 pg/m³ with 28.6-1416.9 pg/m³ in gas and 95.2-1066.2 pg/m³ in particle partition. The three chlorinated OPEs are present at higher concentrations than the other seven non-chlorinated OPEs. Most OPEs had clear seasonal variations that followed the order: spring>summer≈winter>autumn except for tri-isobutyl phosphate (TIBP) and tris-(2-ethylhexyl) phosphate (TEHP). The particle-bound fraction of the total OPEs had little seasonal variations with a mean value of 0.35. Comparing J-P model and Koa model, it was found that the gas/particle partition in the study area was in non-equilibrium condition. LRAT, controlled by seasonal wind direction, was the predominated factor that led to the seasonal variations of OPEs on YXI. The average daily deposition flux of total OPEs was 13.0 ng/m² with an annual total deposition of 15.06 g.

Seasonal variation, source identification, and risk assessment of organophosphate ester flame retardants and plasticizers in surficial sediments from Liao River estuary wetland, China

Organophosphate ester (OPE) flame retardants and plasticizers in surficial sediments were collected in Liao River estuarine wetland during the dry, flood, and level periods to understand the seasonal variation, potential sources, and environmental risks. The concentrations of ∑₁₃OPEs ranged from 19.5 to 67.0 ng g^-1 dry weight (dw), with an average concentration of 30.6 ng g^-1 dw. OPEs pollution displayed a seasonal variation, the concentrations of OPEs in dry period > level period > flood period. Tributyl-n-phosphate was the predominant OPEs, which accounts for 29.7% of ∑₁₃OPEs. Principal component analysis and positive matrix factorization suggested that the pollution sources of OPEs also varied seasonally. The ecological risk of OPEs to aquatic organisms was low, and the non-carcinogenic and carcinogenic risks to human beings were also far below the acceptable level. 2-Ethylhexyl diphenyl phosphate was the major compound causing ecological and non-carcinogenic risk, while tris-(2-chloroethyl) phosphate had the highest carcinogenic risk.

A review of environmental occurrence, analysis, bioaccumulation, and toxicity of organophosphate esters

The ban and restriction of polychlorinated biphenyls (PCBs) and major brominated flame retardants (BFRs), including hexabromocyclododecane (HBCD) and polybrominated diphenyl ethers (PBDEs), due to their confirmed detrimental effects on wildlife and humans have paved the way for the wide application of organophosphate esters (OPEs). OPEs have been extensively used as alternative flame retardants, plasticizer, and antifoaming agents in various industrial and consumer products, which leads to an increase in production, usage, and discharge in the environment. We compile recent information on the production/usage and physicochemical properties of OPEs and discussed and compared the available sample treatment and analysis techniques of OPEs, including extraction, clean-up, and instrumental analysis. The occurrence of OPEs in sediment, aquatic biota, surface, and drinking water is documented. Toxicity, human exposure, and ecological risks of OPEs were summarized; toxicological data of several OPEs shows different adverse health effects on aquatic organisms and humans. Much attention was given to document evidence regarding the bioaccumulation and biomagnification potential of OPEs in aquatic organisms. Finally, identified research gaps and avenues for future studies are forwarded.

Organophosphate Esters in Indoor Environment and Metabolites in Human Urine Collected from a Shanghai University

In China, organophosphate esters (OPEs) are widely used in indoor environments. However, there is little information regarding the internal and external exposure of university students to OPEs. Therefore, in this study, nine OPEs and eight OPE metabolites (mOPEs) were measured in indoor dust and atmospheric PM2.5 samples from a university campus in Shanghai, as well as in urine samples collected from the university students. The total concentration of OPEs in the indoor dust in female dormitories (1420 ng/g) was approximately twice that in male dormitories (645 ng/g). In terms of indoor PM2.5, the highest OPE concentration was found in meeting rooms (105 ng/m3, on average), followed by chemical laboratories (51.2 ng/m3), dormitories (44.9 ng/m3), and offices (34.9 ng/m3). The total concentrations of the eight mOPEs ranged from 279 pg/mL to 14,000 pg/mL, with a geometric mean value of 1590 pg/mL. The estimated daily intake values based on the indoor dust and PM2.5 OPE samples (external exposure) were 1-2 orders of magnitude lower than that deduced from the concentration of urinary mOPEs (internal exposure), indicating that dermal contact, dust ingestion, and inhalation do not contribute significantly to OPE exposure in the general population. Moreover, additional exposure routes lead to the accumulation of OPEs in the human body.

Phytotoxicity of tris-(1-chloro-2-propyl) phosphate in soil and its uptake and accumulation by pakchoi (Brassica chinensis L. cv. SuZhou)

This study investigated physiological and biochemical changes in pakchoi at different growth stages (25 and 50 d) under different tris-(1-chloro-2-propyl) phosphate (TCIPP) treatments (10, 100, 500, and 1000 μg kg^-1). The uptake and accumulation of TCIPP by pakchoi and variation of TCIPP speciation in soil were also determined. TCIPP decreased the length and fresh weight of pakchoi root compared with those in blank controls, and this effect was significant when the concentration of TCIPP was higher than 100 μg kg^-1. The fresh weight of pakchoi stems and leaves, the chlorophyll content, and the activities of superoxide dismutase, peroxidase, and catalase in the leaves first increased and then decreased with increasing TCIPP concentration. The inflection point of the variation in these indices was 100 μg kg^-1 TCIPP in soil. The contents of proline and malondialdehyde increased continuously with increasing TCIPP concentration. The uptake of TCIPP by pakchoi increased linearly with increasing TCIPP concentration, and the highest TCIPP concentrations in the roots, stems, and leaves were 275.9, 80.0, and 2126.3 μg kg^-1, respectively. TCIPP was easily transferred from the roots to leaves of pakchoi, with translocation factor of up to 12.6. The content of bioavailable TCIPP in soil was high, accounting for 46.5%. Planting pakchoi could significantly reduce the content of bioavailable TCIPP, with removal rate of 39.9%-54.1%. After 50 d of planting pakchoi, the removal rate of TCIPP in soil (10.4%-18.6%) was significantly higher than that in the control without plant, but the contribution of phytoextraction was small, accounting for 2.62%-26.6%.

Optimization and validation of automated solid-phase microextraction arrow technique for determination of phosphorus flame retardants in water

In the present work, a very sensitive and fully automated direct immersion PAL SPME Arrow procedure, coupled with GC-MS, has been developed and validated for determination of nine phosphorus flame retardants in different types of water samples (river, drinking and rainwater). PDMS/DVB was selected among three commercially available SPME Arrows (PDMS/DVB, DVB/PDMS/CWR and PDMS/CWR), since it resulted in the best sensitivity. The important experimental parameters were optimized via a central composite design response surface methodology and as result, extraction time of 65 min, extraction temperature of 80 °C and added salt concentration of 19% (w/v), were selected as the optimum values. The optimized method showed linear response over the calibration range (2 - 500 ng L^-1), with R²-values higher than 0.9937. The precision (RSD%) measured by replicate analyses (n = 7) was estimated at 2 and 100 ng L^-1 and was less than 29% and 21%, respectively. The LOQ of PAL SPME Arrow, calculated as S/N = 10, was between 0.2 and 1.2 ng L^-1 (for triphenyl phosphate and tris-(1‑chloro‑2-propyl) phosphate, respectively) with extraction efficiencies between 5.9 and 31% (for tris-(1,3-dichloro-2-propyl) phosphate and tri-n‑butyl phosphate, respectively). To assess the performance of the developed technique for real samples, two river water samples, tap water from two regions and a rainwater sample were analyzed. Most of the target analytes were observed in the river samples with concentrations of 1.0 - 250 ng L^-1 and the obtained recoveries at 50 ng L^-1 ranged between 60 and 107%. Considering the figures of merit of the optimized method, PAL SPME Arrow-GC-MS showed to be the most sensitive analytical approach for determination of phosphorus flame retardants in water, with satisfying precision and accuracy, compared with conventional SPME-NPD, LLE-GC-MS and SPE-LC-MS/MS.

A review of organophosphate flame retardants and plasticizers in the environment: Analysis, occurrence and risk assessment

Organophosphate esters (OPEs) are used as additives in flame retardants and plasticizers. Due to phase out of several congeners of polybrominated diphenyl ethers (PBDEs), the application of organophosphorus flame retardants (OPFRs) is continuously increasing over the years. As a consequence, large amounts of OPEs enter the environment. Sewage and solid waste (especially e-waste) treatment plants are the important sources of OPEs released to the environment. Other sources include emissions of OPE-containing materials and vehicle fuel into the atmosphere. OPEs are widely detected in air, dust, water, soil, sediment and sludge. To know the pollution situation of OPEs, a variety of methods on their pretreatment and determination have been developed. We discussed and compared the analytical methods of OPEs, including extraction, purification as well as GC- and LC-based determination techniques. Much attention has been paid to OPEs because some of them are recognized highly toxic to biota, and the toxicological investigations of the most concerned OPEs were summarized. Risk assessments showed that the aquatic and benthic environments in some regions are under considerable ecological risks of OPEs. Finally, we pointed out problems in the current studies on OPEs and provided some suggestions for future research.

Multi-residue analysis of several high-production-volume chemicals present in the particulate matter from outdoor air. A preliminary human exposure estimation

A multi-residue method based on gas chromatography-mass spectrometry combined with pressurised liquid extraction was developed to determine seven organophosphate esters (OPEs), six phthalate esters (PAEs), four benzotriazoles (BTRs), five benzothiazoles (BTHs) and four benzenesulfonamides (BSAs) in particulate matter samples from outdoor air. All of these compounds are among the named high-production volume chemicals (HPVCs) and some of them have shown to be harmful to human, therefore they have been subject for legal regulation in order to control their production and usage. Under optimised conditions, high recovery values (>80%) and low detection limits (pg m-3) were obtained for most of the compounds with accuracy values between 83% and 118%. Some samples from two locations surrounded by different industry activities showed the widespread occurrence of all the PAEs, followed by some OPEs. Diethylhexyl phthalate (DEHP) was the most abundant compound with concentrations ranging from 1.9 to 97.7 ng m-3. With the concentrations found, estimated daily intakes through outdoor inhalation were calculated for each contaminant and for different population groups classified by age (infants, children and adults) in two possible exposure scenarios (low and high). Then, hazard quotients and carcinogenic risks were estimated for several compounds, those that had toxicological parameters available. This preliminary result showed no significant risks via ambient inhalation for the exposed population, however more research is needed to confirm the present results.

Concentrations, sources and human exposure implications of organophosphate esters in indoor dust from South Africa

The concentrations of four organophosphate esters (OPEs) were measured in 50 dust samples from homes (n = 10), offices (n = 9), university computer laboratories (n = 12) and cars (n = 19) in Durban, South Africa. The median concentrations Σ_n=₄ OPEs were 22940, 26930, 19565 and 49010 ng g⁻¹ in homes, offices, university computer laboratories and cars respectively. OPEs were detected in all samples with the exception of one car and one computer laboratory sample in which TDCIPP was not detected. Significant association of indoor characteristics with OPE concentrations was observed. OPEs positively correlated (r = 0.22, p value = 0.4862) with electronics and correlated (r = 0.522, p value = 0.0675) with foams and furniture in homes. By employing the median concentrations and an average dust intake rate, the exposure doses (ng d^-1) were found to be 169 (TCEP), 74 (TCIPP), 162 (TDCIPP) and 55 (TPHP) for adults; 159 (TCEP), 70 (TCIPP), 108 (TDCIPP) and 57 (TPHP) for teenagers; 317 (TCEP), 152 (TCIPP), 334 (TDCIPP) and 94 (TPHP) for toddlers. The predominance and exposure magnitude of OPEs in the South African environment require further investigations to determine cumulative human health effects arising from mixtures of these compounds through multiple exposure routes.

Organophosphate flame retardants in total suspended particulates from an urban area of zhengzhou, China: Temporal variations, potential affecting factors, and health risk assessment

Organophosphate esters (OPEs) are widely used as flame retardants and plasticizers in industry and daily life, but the partition of OPEs to particles is still unclear because of the wide range of their physicochemical properties. In this study, six target OPEs with different vapor pressures (log P_L) were measured from 30 total suspended particulate (TSP) samples collected from an urban area of Zhengzhou from June to November in 2018. The total concentration of OPEs ranged from 0.30 to 3.46 ng/m³, with average concentration of 1.04 ng/m³. Tris (chloroethyl) phosphate (TCEP), tris(2-chloroisopropyl) phosphate (TCPP), and tributyl phosphate (TnBP) were most abundant in TSP, accounting for approximately 86.0% to the total OPEs. The temporal variations showed a specific trend that OPE concentrations in TSP were much higher in autumn than those of summer. Significant positive correlations were observed between TSP concentration in air and the total concentration of OPEs in TSP, with r up to 0.596. Particle concentrations caused major changes on OPE concentrations in TSP with octanol-air partition coefficient (log K_OA) between 7.7 and 10 but had no significant influence on the OPEs with log K_OA higher than 12. Temperature had significant influence on the total and individual OPEs with high vapor pressures (log P_L > -4.0), indicating that log K_OA and log P_L had significant influence on the OPE concentrations in TSP and may be one of the key factors on their temporal variations. Temperature had significant influence on OPE concentrations in TSP due to the strong temperature dependency of log K_OA and log P_L. No significant relationships were found between the wind speed and OPE concentrations in TSP, suggesting that OPEs detected in TSP might be emitted from the local sources. The hazards quotient (HQ) values were 6-8 orders of magnitude lower than 1, indicating that there was a low risk to local residents from the exposure to OPEs in TSP. This study preliminarily illuminates the potential affecting factors on the temporal variations of OPEs in TSP. It would be helpful for investigating the gas-particle partitioning behaviors and human health risks of OPEs in air.

Mining the Chemical Information on Urban Wastewater: Monitoring Human Exposure to Phosphorus Flame Retardants and Plasticizers

At the individual level, exposure to contaminants is generally assessed through the analysis of specific biomarkers in biological matrices. However, these studies are costly and logistically demanding, limiting their applicability to monitor population-wide exposure over time and space. By focusing on a selection of exposure biomarkers to phosphorus flame retardants and plasticizers (PFRs), this study aims to explore the possibility of using wastewater as a complementary source of information about exposure. Wastewater samples were collected from five cities in Europe and analyzed using a previously established method. Substantial differences in biomarker levels were observed between the investigated catchments, suggesting differences in exposure. Time trends in biomarkers observed between 2013 and 2016 were found to agree with results from human biomonitoring studies and reports about production volumes. Using Monte Carlo simulations, average urinary concentrations were estimated. These were generally higher compared to results from human biomonitoring studies. Various explanations for these differences were formulated (i.e., other excretion routes, external sources and different sampling approaches). Obtained results show that wastewater analysis provides unique information about geographical and temporal differences in exposure, which would be difficult to gather using other monitoring tools.

Presence of diphenyl phosphate and aryl-phosphate flame retardants in indoor dust from different microenvironments in Spain and the Netherlands and estimation of human exposure

Phosphate flame retardants (PFRs) are ubiquitous chemicals in the indoor environment. Diphenyl phosphate (DPHP) is a major metabolite and a common biomarker of aryl-PFRs. Since it is used as a chemical additive and it is a common impurity of aryl-PFRs as well as a degradation product, its presence in indoor dust as an additional source of exposure should not be easily ruled out. In this study, DPHP (and TPHP) are measured in indoor dust in samples collected in Spain and in the Netherlands (n=80). Additionally, the presence of other emerging aryl-PFRs was monitored by target screening. TPHP and DPHP were present in all samples in the ranges 169-142,459ng/g and 106-79,661ng/g, respectively. DPHP concentrations were strongly correlated to the TPHP levels (r=0.90, p<0.01), suggesting that DPHP could be present as degradation product of TPHP or other aryl-PFRs. Estimated exposures for adults and toddlers in Spain to TPHP and DPHP via dust ingestion (country for which the number of samples was higher) were much lower than the estimated reference dose (US EPA) for TPHP. However, other routes of exposure may contribute to the overall internal exposure (diet, dermal contact with dust/consumer products and inhalation of indoor air). The estimated urinary DPHP levels for adults and toddlers in Spain (0.002-0.032ng/mL) as a result of dust ingestion were low in comparison with the reported levels, indicating a low contribution of this source of contamination to the overall DPHP exposure. Other aryl-PFRs, namely cresyl diphenyl phosphate (CDP), resorcinol bis(diphenyl phosphate) (RDP), 2-ethylhexyl diphenyl phosphate (EDPHP), isodecyl diphenyl phosphate (IDP) and bisphenol A bis(diphenyl phosphate) (BDP), were all detected in indoor dust, however, with lower frequency.

Effects of triphenyl phosphate on growth, reproduction and transcription of genes of Daphnia magna

The additive flame retardant triphenyl phosphate (TPHP) has been frequently detected in environments and biota. Evidences indicate that TPHP has potential risks to aquatic organisms. Seldom has been reported about its chronic effects to aquatic organism at low trophic levels, such as Cladocera. In the present study, <12 h old Daphnia magna (D. magna) were exposed to 0, 5, 50 or 500 μg/L TPHP for 21 days to investigate the chronic effects of TPHP on body length, fecundity and survival. Meanwhile, D. magna PCR arrays were used to evaluate the transcriptional responses of 155 genes involved in 40 pathways. Exposure to 500 μg/L TPHP for 21 days significantly decreased the body lengths of both F0 and F1 generation and inhibited the fecundity of F0 generation. Results of RT-qPCR showed that the expressions of 76 genes involved in 15 pathways were significantly altered after exposure to 500 μg/L TPHP for 21 days. The significantly altered pathways related to genetic information processing, cellular process and metabolism might be responsible for the observed effects of TPHP. Overall, our results showed that chronic exposure to TPHP caused developmental and reproductive toxicities to D. magna.

Leaching of TCIPP from furniture foam is rapid and substantial

A series of laboratory experiments were conducted, in which waste furniture polyurethane foam samples containing tris (1-chloro-2-propyl) phosphate (TCIPP) were contacted with a range of leaching fluids, formulated to simulate the composition of landfill leachate. Leaching was examined under a number of different scenarios, such as: dissolved humic matter concentration, pH, and temperature, as well as the effect of agitation, and waste:leaching fluid contact duration. In addition to single batch (no replenishment of leaching fluid), serial batch (draining of leachate and replenishment with fresh leaching fluid at various time intervals) experiments were conducted. Leaching of TCIPP from PUF appears to be a first order process. Concentrations of TCIPP in leachate generated by the experiments in this study ranged from 13 mg L^-1 to 130 mg L^-1. In serial batch leaching experiments, >95% of TCIPP was depleted from PUF after 168 h total contact with leaching fluid. Our experiments indicate leaching is potentially a very significant pathway of TCIPP emissions to the environment.

Organophosphorus Flame Retardants and Plasticizers in Building and Decoration Materials and Their Potential Burdens in Newly Decorated Houses in China

Organophosphorus flame retardants (OPFRs) have been increasingly used in various building and decoration materials to fulfill fire safety standards since the phasing out of polybrominated diphenyl ethers. We determined OPFR concentrations in the most commonly used building and decoration materials available in local markets and online in China. The OPFR concentrations varied significantly, from 14.78 ng/g (putty powder) to 9649000 ng/g (expanded polystyrene panel (EPS)). Relatively high concentrations of OPFRs were found in foam samples, followed by nonwoven and polyvinyl chloride (PVC) wallpaper, PVC pipes, sealing materials, boards, and paints. Low concentrations were found mostly in wall decoration powders, suggesting that no OPFRs had been added to these powders. Tris(1-chloro-2-propyl) phosphate and tris(1,3-dichloro-2-propyl) phosphate were the most detected halogenated OPFRs, while tri-n-butyl phosphate and tris(2-butoxyethyl) phosphate were the dominant nonhalogenated OPFRs, implying that they are commonly used in building and decoration materials. The estimated OPFR burden in interior decoration using nonwoven wallpaper was 330- and 2110-fold higher than that using latex paint and diatomite, respectively. The emission periods of OPFRs from nonwoven and PVC wallpaper may be greater than 13 years. We estimated that the total burden of OPFRs for decoration using wallpaper in newly decorated houses in China is ∼63 t/y. Significantly higher concentrations of OPFRs in interior decoration materials, especially nonwoven wallpaper, pose potential health risks to the people using the buildings.

Occurrence and fate of organophosphate ester flame retardants and plasticizers in indoor air and dust of Nepal: Implication for human exposure

The present study was carried out in Nepal, a landlocked country located between world's two most populous countries i.e. India and China. In this study, the occurrence, profiles, spatial distributions and fate of eight organophosphate ester flame retardants (OPFRs) were investigated in indoor air and house dust. Overall, the concentrations of ∑OPFR were in the range of 153-12100 ng/g (median732 ng/g) and 0.32-64 ng/m³ (median 5.2 ng/m³) in house dust and indoor air, respectively. The sources of high OPFR in the indoor environment could be from locally used wide variety of consumer products and building materials in Nepalese houses. Significantly, high concentration of tri-cresyl phosphate (TMPP) was found both in air and dust, while tri (2-ethylhexyl) phosphate (TEHP) had the highest concentration in air samples. It might be due to fact that the high concentrations of TMPP are related to intense traffic and/or nearby airports. On the other hand, significantly high concentration of TEHP could be due to anthropogenic activities. Only TEHP showed positive correlation between indoor air and house dust (Rho = 0.517, p < 0.01), while rest of compounds were either less correlated or not correlated at all. The estimated human exposure to ∑OPFR via different pathway of intake suggested dermal absorption via indoor dust as major pathway of human exposure to both children and adult population. However, other pathways of OPFR intake such as dietary or dermal absorption via soil may still be significant in case of Nepal.

Organophosphate flame retardants (OPFRs) in indoor and outdoor air in the Rhine/Main area, Germany: comparison of concentrations and distribution profiles in different microenvironments

The concentrations of 9 organophosphate flame retardants (OPFRs) were determined in 56 indoor and 9 outdoor air samples in the Rhine/Main area in Germany. The indoor samples were collected from seven different indoor microenvironments including private cars, private homes, floor/carpet stores, building material markets, schools, offices, and day care centers, while outdoor samples were simultaneously collected close to the indoor sampling locations. The total OPFR concentrations (∑OPFRs) in indoor air ranged from 3.30 to 751.0 ng/m³ with a median of 40.23 ng/m³, which was approximately eight times higher than those in outdoor air (median 5.38 ng/m³), indicating that sources of OPFRs predominate in the indoor environment. Tris(2-chloroisopropyl)phosphate (TCPP), tris(isobutyl)phosphate (TiBP), and tributyl phosphate (TnBP) were the dominating compounds both in indoor and outdoor air. The median concentration of ∑OPFRs in private cars (180.3 ng/m³) was significantly higher than that in private homes (12.51 ng/m³), schools (36.23 ng/m³), day care centers (31.80 ng/m³), and building material markets (31.17 ng/m³) (p < 0.05). Distribution profiles of OPFRs varied among different indoor microenvironments, which are evidenced by dominating indoor air concentrations of non-Cl-OPFRs in day care centers, floor/carpet stores, schools, and of Cl-OPFRs in other indoor microenvironments. Multivariate analyses revealed three distinct groups for OPFRs, i.e., TiBP/TnBP, TEP/TCEP/TDCPP, and TCPP, whose concentrations were closely associated with the distribution profiles and pollution characteristics of materials predominating in different indoor microenvironments.

Determination of the volatile fraction of phosphorus flame retardants in cushioning foam of upholstered furniture: towards respiratory exposure assessment

The purpose of this paper was to highlight potential exposure in indoor air to phosphorus flame retardants (PFRs) due to their use in upholstered furniture. For that, an analytical method of PFRs by headspace coupled to solid-phase micro-extraction (HS-SPME) was developed on cushioning foams in order to determine the PFRs' volatile fraction in the material. Tests on model foams proved the feasibility of the method. The average repeatability (RSD) is 6.3 % and the limits of detection range from 0.33 to 1.29 μg g(-1) of foam, depending on the PFRs. Results showed that some PFRs can actually be emitted in air, leading to a potential risk of exposure by inhalation. The volatile fraction can be high (up to 98 % of the total PFRs amount) and depends on the physicochemical properties of flame retardants, on the textural characteristics of the materials and on the temperature. The methodology developed for cushioning foams could be further applied to other types of materials and can be used to rate them according to their potential releases of phosphorus flame retardants.

Compositional Analysis of Commercial Oligomeric Organophosphorus Flame Retardants Used as Alternatives for PBDEs: Concentrations and Potential Environmental Emissions of Oligomers and Impurities

Four commercial oligomeric organophosphorus flame retardants (o-PFRs) were characterized using a refractive index detector and atmospheric pressure photoionization (APPI)-quadrupole time-of-flight mass spectrometry (QTOF-MS) compatible with gel permeation chromatography (GPC). Commercial o-PFRs consisted of approximately 90% or more oligomers and several impurities. Triphenyl phosphate (TPHP), tris(dimethylphenyl) phosphate (TDMPP), tris(2-chloroisopropyl) phosphate (TCIPP), and some new impurities were identified as byproducts of some manufacturing process of commercial o-PFRs for the first time. The concentrations of TPHP, TDMPP, and TCIPP were more than 1 weight %, whereas those of new impurities might be approximately 1 weight % by comparison among their abundances acquired through GPC-APPI-QTOF-MS analysis. Based on their vapor pressure and water solubility estimations, the potential environmental emissions of low molecular weight impurities were expected to be higher than those of oligomers. The presence and environmental emissions of low molecular weight impurities might be regarded as risk factors along with commercial o-PFRs.

Organophosphorus flame retardants and plasticizers: sources, occurrence, toxicity and human exposure

Due to the restricted use and ban of brominated flame retardants, organophosphorus compounds (OPs), extensively used as flame retardants and plasticizers, are ubiquitous in various environmental compartments worldwide. The present study shows that the release of OPs from a wide variety of commercial products and wastewater discharge might be considered as primary emission sources and that high potential of long-range atmospheric transport and persistence of OPs would be responsible for their presence in various matrices on a global scale. The occurrence and environmental behaviors of OPs in diverse matrices (e.g., dust, air, water, sediment, soil and biota) are reviewed. Human exposures to OPs via dermal contact, dust ingestion, inhalation and dietary intake are comprehensively evaluated. Finally, this study identifies gaps in the existing issues and generates a future agenda for the emerging contaminants OPs.

Pilot-scale incineration of wastes with high content of chlorinated and non-halogenated organophosphorus flame retardants used as alternatives for PBDEs

Chlorinated and non-halogenated organophosphorus flame retardants (OPFRs) including tris(2-chloroisopropyl) phosphate (TCIPP), diethylene glycol bis(di(2-chloroisopropyl) phosphate) (DEG-BDCIPP), triphenyl phosphate (TPHP), and bisphenol A bis(diphenyl phosphate) (BPA-BDPP) have been used increasingly as alternatives to polybrominated diphenyl ethers and other brominated flame retardants. For this study, five batches of incineration experiments of wastes containing approximately 1% of TCIPP, DEG-BDCIPP, TPHP, and BPA-BDPP were conducted using a pilot-scale incinerator. Destruction and emission behaviors of OPFRs were investigated along with the effects on behaviors of unintentional persistent organic pollutants (POPs) such as polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin-like polychlorinated biphenyls (dl-PCBs), hexachlorobenzene (HCB), pentachlorobenzene (PeCB), and pentachlorophenol (PCP). Incineration conditions were chosen according to current regulations for waste incinerators in Japan and UNEP. The OPFRs in the input materials were mainly destroyed in the primary combustion with destruction efficiencies greater than 99.999%. Concentrations of the OPFRs in the exhaust gases and ash were, respectively, <0.01-0.048 μg m(-3) and <0.5-68 μg kg(-1). Almost all of the total phosphorus in the input materials was partitioned into the ash, but less into final exit gases, indicating negligible emissions of volatile phosphorus compounds during incineration. Inputs of chlorinated OPFRs did not affect the formation markedly. Destruction and emission behaviors of unintentional POPs were investigated. Emissions of such POPs in exhaust gases and the ash were lower than the Japanese and international standards. Results show that even in wastes with high contents of chlorinated and non-halogenated OPFRs, waste incineration by the current regulations for the waste incinerators can control environmental emissions of OPFRs and unintentional POPs. Incineration is regarded as a best available technology (BAT) for waste management systems.

Simultaneous determination of thirteen organophosphate esters in settled indoor house dust and a comparison between two sampling techniques

An analytical method for the simultaneous determination of 13 organophosphate esters (OPEs) in house dust was developed. The method is based on solvent extraction by sonication, sample cleanup by solid phase extraction (SPE), and analysis by gas chromatography-positive chemical ionization-tandem mass spectrometry (GC/PCI-MS/MS). Method detection limits (MDLs) ranged from 0.03 to 0.43 μg/g and recoveries from 60% to 118%. The inter- and intra-day variations ranged from 3% to 23%. The method was applied to dust samples collected using two vacuum sampling techniques from 134 urban Canadian homes: a sample of fresh or "active" dust (FD) collected by technicians and a composite sample taken from the household vacuum cleaner (HD). Results show that the two sampling methods (i.e., FD vs HD) provided comparable results. Tributoxyethyl phosphate (TBEP), triphenyl phosphate (TPhP), tris(chloropropyl) phosphate (TCPP), tri(2-chloroethyl) phosphate (TCEP), tris(dichloro-isopropyl) phosphate (TDCPP), tricresyl phosphate (TCrP), and tri-n-butyl phosphate (TnBP) were detected in the majority of samples. The most predominant OPE was TBEP, with median concentrations of 31.9 μg/g and 22.8 μg/g in FD and HD samples, respectively, 1 to 2 orders of magnitude higher than other OPEs. The method was also applied to the analysis of OPEs in the National Institute of Standards and Technology (NIST) standard reference material (NIST SRM 2585, organic contaminants in house dust). The results from SRM 2585 may contribute to the certification of OPE concentration values in this SRM.

Electron impact, electron capture negative ionization and positive chemical ionization mass spectra of organophosphorus flame retardants and plasticizers

Phosphate esters are important commercial products that have been used both as flame retardants and as plasticizers. To analyze these compounds by gas chromatographic mass spectrometry, it is important to understand the mass spectra of these compounds using various ionization modes. This paper is a systematic overview of the electron impact (EI), electron capture negative ionization (ECNI) and positive chemical ionization (PCI) mass spectra of 13 organophosphate esters. These data are useful for developing and optimizing analytical measurements. The EI spectra of these 13 compounds are dominated by ions such as H4 PO4 (+) , (M - Cl)(+) , (M - CH2 Cl)(+) or (M)(+) depending on specific chemical structures. The ECNI spectra are generally dominated by (M - R)(-) . The PCI spectra are mainly dominated by the protonated molecular ion (M + H)(+) . The branching of the alkyl substituents, the halogenation of the substituents and, for aromatic phosphate esters, ortho alkylation of the ring are all significant factors controlling the details of the fragmentation processes. EI provides the best sensitivity for the quantitative measurement of these compounds, but PCI and ECNI both have considerable qualitative selectivity.

Phosphorus flame retardants: properties, production, environmental occurrence, toxicity and analysis

Since the ban on some brominated flame retardants (BFRs), phosphorus flame retardants (PFRs), which were responsible for 20% of the flame retardant (FR) consumption in 2006 in Europe, are often proposed as alternatives for BFRs. PFRs can be divided in three main groups, inorganic, organic and halogen containing PFRs. Most of the PFRs have a mechanism of action in the solid phase of burning materials (char formation), but some may also be active in the gas phase. Some PFRs are reactive FRs, which means they are chemically bound to a polymer, whereas others are additive and mixed into the polymer. The focus of this report is limited to the PFRs mentioned in the literature as potential substitutes for BFRs. The physico-chemical properties, applications and production volumes of PFRs are given. Non-halogenated PFRs are often used as plasticisers as well. Limited information is available on the occurrence of PFRs in the environment. For triphenyl phosphate (TPhP), tricresylphosphate (TCP), tris(2-chloroethyl)phosphate (TCEP), tris(chloropropyl)phosphate (TCPP), tris(1,3-dichloro-2-propyl)phosphate (TDCPP), and tetrekis(2-chlorethyl)dichloroisopentyldiphosphate (V6) a number of studies have been performed on their occurrence in air, water and sediment, but limited data were found on their occurrence in biota. Concentrations found for these PFRs in air were up to 47 μg m(-3), in sediment levels up to 24 mg kg(-1) were found, and in surface water concentrations up to 379 ng L(-1). In all these matrices TCPP was dominant. Concentrations found in dust were up to 67 mg kg(-1), with TDCPP being the dominant PFR. PFR concentrations reported were often higher than polybrominated diphenylether (PBDE) concentrations, and the human exposure due to PFR concentrations in indoor air appears to be higher than exposure due to PBDE concentrations in indoor air. Only the Cl-containing PFRs are carcinogenic. Other negative human health effects were found for Cl-containing PFRs as well as for TCP, which suggest that those PFRs would not be suitable alternatives for BFRs. TPhP, diphenylcresylphosphate (DCP) and TCP would not be suitable alternatives either, because they are considered to be toxic to (aquatic) organisms. Diethylphosphinic acid is, just like TCEP, considered to be very persistent. From an environmental perspective, resorcinol-bis(diphenylphosphate) (RDP), bisphenol-A diphenyl phosphate (BADP) and melamine polyphosphate, may be suitable good substitutes for BFRs. Information on PFR analysis in air, water and sediment is limited to TCEP, TCPP, TPhP, TCP and some other organophosphate esters. For air sampling passive samplers have been used as well as solid phase extraction (SPE) membranes, SPE cartridges, and solid phase micro-extraction (SPME). For extraction of PFRs from water SPE is recommended, because this method gives good recoveries (67-105%) and acceptable relative standard deviations (RSDs) (<20%), and offers the option of on-line coupling with a detection system. For the extraction of PFRs from sediment microwave-assisted extraction (MAE) is recommended. The recoveries (78-105%) and RSDs (3-8%) are good and the method is faster and requires less solvent compared to other methods. For the final instrumental analysis of PFRs, gas chromatography-flame photometric detection (GC-FPD), GC-nitrogen-phosphorus detection (NPD), GC-atomic emission detection (AED), GC-mass spectrometry (MS) as well as liquid chromatography (LC)-MS/MS and GC-Inductively-coupled plasma-MS (ICP-MS) are used. GC-ICP-MS is a promising method, because it provides much less complex chromatograms while offering the same recoveries and limits of detection (LOD) (instrumental LOD is 5-10 ng mL(-1)) compared to GC-NPD and GC-MS, which are frequently used methods for PFR analysis. GC-MS offers a higher selectivity than GC-NPD and the possibility of using isotopically labeled compounds for quantification.

Simultaneous selective detection of organophosphate and phthalate esters using gas chromatography with positive ion chemical ionization tandem mass spectrometry and its application to indoor air and dust

A selective and sensitive method for the simultaneous determination of 14 organophosphate and six phthalate esters using gas chromatography (GC) and mass spectrometry (MS) is presented. Both of these compound classes are frequently found in the indoor environment due to their use as bulk additives in numerous polymers, consumer products and building materials. GC/MS utilizing positive ion chemical ionisation (PICI) in selected reaction monitoring (SRM) mode with isobutane as the reagent gas was found to be the best of the tested methods; it proved superior to electron ionisation (EI) in selected ion monitoring (SIM) mode and to PICI using methane as the reagent gas. The method was applied to indoor air samples collected by active air sampling using solid-phase extraction (SPE) cartridges. Organophosphates and phthalates were simultaneously determined with method detection limits (MDLs) in the range of 0.1-47 ng m(-3). For most compounds the MDLs were ≤0.2 ng m(-3), but due to the presence of some of these ubiquitous indoor air pollutants in the blanks, significantly higher MDLs were observed for a few compounds. Finally, the method was also applied in the screening of a much more complex sample matrix, indoor dust.

Respiratory and dermal exposure to organophosphorus flame retardants and tetrabromobisphenol A at five work environments

Organophosphorus compounds (OPs) and tetrabromobisphenol A (TBBPA) are widely utilized as flame retardants (FRs) in plastics, textiles, rubbers, and building materials. Eight OPs and TBBPA were quantified by GC/MS from air samples collected from a furniture workshop, a circuit board factory, two electronics dismantling facilities, a computer classroom, and offices and social premises. In addition, dermal exposure was assessed with patch and hand wash samples at some workplaces. Triphenyl phosphate, tris(2-chloroethyl) phosphate, and tris(2-chloroisopropyl) phosphate were typical contaminants of the workplaces, whereas TBBPA, tricresyl phosphate, tri-n-butyl phosphate, and tris(2-ethylhexyl) phosphate were rather site-specific. The highest geometric mean of total FRs in the air samples was measured in personal samples atthe electronics dismantling facilities (2.9 and 3.8 microg/m3), whereas the stationary sample results from the other environments ranged between 90 and 720 ng/m3. Stationary samplings underestimated the personal exposure at three out of four work places where comparisons were made. Dermal exposure was shown for the first time at these occupational settings. The geometric mean of totalFR levels in patch samples ranged between 1.5 and 24 ng/cm2 and in hand wash samples between 3.5 and 34 microg/ two hands. The health effects of the measured FR levels remain unknown.

Biosensor system for continuous monitoring of organophosphate aerosols

An enzyme-based monitoring system provides the basis for continuous sampling of organophosphate contamination in air. The enzymes butyrylcholinesterase (BuChE) and organophosphate hydrolase (OPH) are stabilized by encapsulation in biomimetic silica nanoparticles, entrained within a packed bed column. The resulting immobilized enzyme reactors (IMERs) were integrated with an impinger-based aerosol sampling system for collection of chemical contaminants in air. The sampling system was operated continuously and organophosphate detection was performed in real-time by single wavelength analysis of enzyme hydrolysis products. The resulting sensor system detects organophosphates based on either enzyme inhibition (of BuChE) or substrate hydrolysis (by OPH). The detection limits of the IMERs for specific organophosphates are presented and discussed. The system proved suitable for detection of a range of organophosphates including paraoxon, demeton-S and malathion.

Microwave-assisted extraction of organophosphate flame retardants and plasticizers from indoor dust samples

A procedure for the determination of eight organophosphate flame retardants and plasticizers in dust samples is presented. Microwave-assisted extraction and gas chromatography (GC) with nitrogen-phosphorus detection (NPD) were used for sample preparation and analytes quantification, respectively. Influence of different variables (type and volume of organic solvent, temperature, time, agitation, etc.) on the yield of the extraction step was evaluated. The most important factor was the type of solvent, with the highest efficiencies corresponding to acetone. Under final conditions 10 mL of this solvent were employed. The extraction was carried out at 130 degrees C and satisfactory yields, similar to those obtained with the Soxhlet technique, were achieved. Due to the high content of organic carbon in dust samples, primary acetone extracts had to be subjected to intensive clean-up. Dilution with ultrapure water followed by concentration on a reversed-phase sorbent and further purification using silica, allowed a significant reduction of co-extracted interferences. Application of the developed methodology to indoor dust from private houses showed important concentrations of several organophosphate esters. The highest levels, up to 19 microg/g, corresponded to tris(butoxyethyl) phosphate; moreover, average values of two chlorinated compounds, used as flame retardants and considered as the most concerning species in the group, exceeded the 1 microg/g level.

Optimisation of a selective method for the determination of organophosphorous triesters in outdoor particulate samples by pressurised liquid extraction and large-volume injection gas chromatography–positive chemical ionisation–tandem mass spectrometry

A selective analytical method for the determination of nine organophosphate triesters and triphenylphosphine oxide (TPPO) in outdoor particulate matter is presented. It involves a fully automated pressurised liquid extraction (PLE) step, integrating an alumina clean-up process, and subsequent determination by large-volume injection gas chromatography-positive chemical ionisation-tandem mass spectrometry (LVI-GC-PCI-MS/MS). The extraction variables (solvent, amount of adsorbent, temperature, time and number of cycles) were optimised using a multicriteria strategy which implements a desirability function that maximises both extraction and clean-up efficiencies while searching for the best-compromise PLE conditions. The final method affords quantification limits of between 0.01 and 0.3 microg g(-1) and recoveries of >80%, with the exceptions of the most polar analytes, TCEP and TPPO (~65%) for both urban dust and PM10 samples. Moreover, the method permitted the levels of these compounds in dust deposited outdoors (between LOD and 0.5 microg g(-1) for TEHP) and PM10 samples (between LOD and 2.4 microg m(-3) for TiBP) to be measured and reported for the first time.

Optimisation of a matrix solid-phase dispersion method for the determination of organophosphate compounds in dust samples

A fast and inexpensive sample preparation procedure based on the matrix solid-phase dispersion (MSPD) technique is proposed for the isolation of several organophosphate esters (mainly employed as flame retardants and plasticizers) from indoor dust samples. Extraction and clean-up were carried out in a single step and target compounds were determined by gas chromatography (GC) with nitrogen-phosphorus detection (NPD). The main parameters affecting extraction yield and selectivity, such as type and amount of dispersant material, clean-up co-sorbent and extraction solvent, were evaluated and optimised. Under final conditions, 0.5 g of dust were dispersed with equal amounts of anhydrous sodium sulphate and Florisil, and loaded on the top of a polypropylene cartridge containing 0.5 g of alumina. The dispersed sample was washed with 2 mL of n-hexane to remove the least polar interferences and analytes were eluted with 3 mL of acetone. Recoveries of the proposed method for spiked samples ranged from 80 to 116%, and the day-to-day variability remained between 5 and 10%. Data on levels of organophosphate species in dust from private houses and vehicle cabins are provided. In both cases, the lowest concentrations corresponded to the short chain, non-chlorinated, alkyl organophosphates, whereas mean values above 1 microg g(-1) were measured for the rest of analytes.