The occurrence and profiles of 15 organophosphate flame retardants/plasticizers (OPFRs) (3 chlorinated Cl-, 2 aryl-, 5 non-Cl alkyl-, and 5 other types of OPFRs) were investigated in indoor air and ...dust collected from various microenvironments, including homes in the Albany area of New York State, United States. Concurrent indoor air and dust were collected from floors and window sills at homes and fire stations to investigate the partitioning of OPFRs between the vapor and particulate phases of air and dust. The total concentrations of OPFRs in bulk air (vapor plus particulate phases) were found at several tens to hundreds of ng/m3, with mean concentrations that ranged from 0.12 ng/m3 for tripropyl phosphate (TPP) to 43.8 ng/m3 for tris(1-chloro-2-propyl)phosphate (TCIPP). TCIPP, triethyl phosphate (TEP) and tris(2-butoxyethyl)phosphate (TBOEP) were the predominant compounds found in bulk air, vapor phase, and dust. Among the ten types of microenvironments studied, indoor air samples collected from automobile parts shops contained the highest concentrations of OPFRs (mean: 258 ng/m3), followed by electronics shops, nail salons/shops that sell nail polish, and home construction/interior products shops. Estimated daily intakes of OPFRs via inhalation of air, dermal sorption, and ingestion of dust were 149, 279, and 390 ng/kg bw/day, respectively, which suggested that dust ingestion is an important source of human exposure to OPFRs among the indoor exposure pathways studied.
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•15 OPFRs were measured in indoor air and dust from various microenvironments.•TCIPP was the predominant OPFR found in bulk air.•Automobile-part shops contained the highest concentrations of OPFRs.•Dust ingestion is a major source of human exposure to OPFRs.
Bisphenol A (BPA) is widely used in industrial products. Due to the toxicity of this compound, and to comply with restrictions and regulations, manufacturers have progressively replaced it by ...substitutes. One of the main substitutes used is bisphenol S (BPS). Despite increasing use in many products, the effects of BPS on human health have been little investigated, and studies on percutaneous BPS absorption and particularly toxicokinetic data are lacking. However, the endocrine-disrupting activity of BPA and BPS appears comparable. Dermal contact is a significant source of occupational exposure and is the main route during handling of bisphenol-containing receipts by cashiers. Here, percutaneous BPS absorption was investigated and compared to that of BPA. Experiments were performed according to OECD guidelines. Test compounds dissolved in a vehicle - acetone, artificial sebum or water – were applied in vitro to fresh human skin samples in static Franz diffusion cells. Flux, cumulative absorbed dose and distribution of dose recovered were measured. BPA absorption was vehicle-dependent ranging from 3% with sebum to 41% with water. BPS absorption was much lower than BPA absorption whatever the vehicle tested (less than 1% of applied dose). However, depending on the vehicle 20% to 47% of the applied BPS dose remained in the skin, and was consequently potentially absorbable. Both BPA and BPS were mainly absorbed without biotransformation. Taken together, these results indicate that workers may be exposed to BPS through skin when handling products containing it. This exposure is of concern as its toxicity is currently incompletely understood.
•BPS is absorbed less than BPA in in vitro percutaneous assays.•Large amounts of BPS remain in the skin.•Dermal contact with BPS may lead to exposure.•For both BPA and BPS, absorption results vary depending on vehicle.•The dose absorbed mostly contains unmetabolized bisphenol.
•Occurrence and distribution of BPs and TCS in personal care products were studied.•High levels of BPF indicated the widely use of BPF as a substitute for BPA.•The EDU of targets factored dermal ...absorption rates were markedly lower than the EDI.•The human exposure to BPA from PCPs via dermal contact cannot be neglected.
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Increasing concern has been raised in respect of exposure to bisphenols and triclosan (TCS) due to their widespread use. However, little is known about their occurrence in personal care products (PCPs) or, particularly, their dermal uptake following daily application. It is therefore necessary to evaluate the human health risk of bisphenols and TCS via dermal absorption. In this study, 150 PCPs, covering 11 different categories, were collected in China. The concentrations of seven bisphenol analogues and TCS were measured, and the associated human health risks by dermal contact were estimated. High detection frequencies of TCS (46.7%) and bisphenol AF (38.7%) were found in the PCPs. The highest mean concentration of Σ7BPs (sum concentration of all seven bisphenols) was 77.8ngg−1 found in masks, and the highest mean concentration of TCS was 86.7ngg−1 in hand sanitizers. The bisphenol composition profiles varied among different categories. Bisphenol A and bisphenol F generally showed higher concentrations. Combining the concentrations of the target substances with the daily usage quantities of PCPs and other parameters, the total estimated dermal intakes and uptakes of Σ7BPs and TCS were calculated. The results showed that the former (12.1 and 1.06ng·kg−1bwday−1) were markedly higher than the latter (1.21 and 9.58×10−2ng·kg−1bwday−1), which included dermal absorption rates of the chemicals in the estimation. Although diet is the main source, and oral ingestion is the main route, for human BPA exposure, the results of the estimated dermal uptakes of BPA in the present study combined with those from a European study show that dermal contact is the main route with thermal paper being the main contributor when both unconjugated and conjugated BPA in the human body are considered. The present study also showed that exposure to BPA in PCPs following dermal contact should not be ignored.
Numerous studies have focused on assessing the risk of human exposure to polycyclic aromatic hydrocarbons (PAHs) in indoor dust via dermal contact. However, the dermal bioaccessibility and dermal ...absorption of PAHs in indoor dust have seldom been reported. In the present study, the effects of temperature, sweat ratio, solid-liquid ratio and incubation time on the dermal bioaccessibility of PAHs were examined. Naphthalene, phenanthrene, pyrene and benzoapyrenewere selected for examination in an absorption assay with keratinocyte cells. The results showed the release of PAHs from indoor dust fitted a first-order one-compartment model. Naphthalene had the highest rate of release, which was consistent with the bioaccessibility assay results. In addition, the absorption rate of naphthalene and phenanthrene by keratinocytes was higher than that of pyrene and benzoapyrene, with the latter being of higher molecular weight. These results indicated that low molecular weight PAHs were much more easily absorbed via dermal contact than were high molecular weight PAHs. The dermal bioavailability of PAHs in indoor dust was estimated by multiplying the bioaccessibility of PAHs in indoor dust by the ratio of dermal absorption by skin cells, and ranged from 0.12 to 51.0%. These data will be useful in risk assessments.
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•The dermal bioaccessbility of PAHs is generally correlated with Kow.•LMW PAHs are more easily absorbed via dermal contact than HMW PAHs.•Dermal bioavailability of PAHs ranged from 0.12 to 51.0%.
The dermal bioavailability of PAHs ranging from 0.12 to 51.0% could be employed in risk assessment.
Exposure of e-waste workers to eight halogenated and five organophosphate ester flame retardant chemicals (FRs) was studied at a Canadian e-waste dismantling facility. FR concentrations were measured ...in air and dust samples collected at a central location and at four work benches over five-24 hour periods spanning two weeks. The highest concentrations in air from workbenches were of BDE-209 (median 156 ng m−3), followed by Tris(2-chloroethyl) phosphate (TCEP, median 59 ng m−3). Dust concentrations at the workbenches were higher than those measured at the central location, consistent with the release of contaminated dust during dismantling. Dust concentrations from the workbenches were also dominated by BDE-209 (median 96,300 ng g−1), followed by Triphenyl phosphate (TPhP, median 47,000 ng g−1). Most FRs were in coarse particles 5.6–18 μm diameter and ~30% were in respirable particles (<~3 μm). Exposure estimates indicated that dust ingestion accounted for 63% of total FR exposure; inhalation and dermal absorption contributed 35 and 2%, respectively. Some air and dust concentrations as well as some estimated exposures in this formal facility in a high-income country exceeded those from informal e-waste facilities located in low and middle income countries. Although there is demonstrated toxicity of some FRs, FR exposure in the e-waste industry has received minimal attention and occupational limits do not exist for most FRs.
•Some exposures to FRs were higher in this formal facility than in informal facilities.•BDE-209 had highest air and dust concentrations, followed by organophosphate esters.•~30% of total airborne FR concentrations were in respirable particles <~3 μm.•Dust ingestion accounted for >60% of total FR exposure.•Few occupational limits exist for FR exposure in Canadian e-waste sector.
Tetrachlorvinphos (TCVP) is the pesticidal active ingredient in some collars for dogs and cats. The objective of this study was to provide a refined estimate of dermal penetration of TCVP in humans ...using in silico predictions as well as in vitro and in vivo data. The in vivo dermal absorption of TCVP was previously studied in the rat and shown to be saturable, ranging from 21.7% (10 µg/cm
2
) down to 3% (1000 µg/cm
2
) Subsequent in silico predictions were conducted for rats and humans to provide initial evaluations of species and dose-dependent differences in dermal absorption. A definitive comparison of TCVP systemic exposure in rat and human following dermal application was then conducted via a standard in vitro assay. TCVP dose levels of 10, 100, or 1000 μg/cm
2
were applied to excised rat and human skin mounted in flow-through diffusion cells. The vehicle was 1% hydroxypropylmethylcellulose (HPMC) in water. An additional 5 μg/cm
2
dose was applied to excised human skin only. The in vitro dermal absorption of TCVP was also assessed from artificial sebum at dose levels of 5, 10, or 100 μg/cm
2
applied to human skin only. Utilizing the so-called triple pack approach with in vitro and in vivo rat data and in vitro human data, dermal absorption for TCVP was calculated for humans. In silico modeling indicated absorption of TCVP through human skin might be 3- to 4- fold lower than rat skin at all application levels, with a maximum dermal absorption of 9.6% at the lowest exposure of 10 µg/cm
2
, down to 0.1% at 1000 µg/cm
2
. Similar species differences were also found in the definitive in vitro absorption assays. Modeling overestimated TCVP human dermal absorption (9.6%) as compared to excised human skin results (1.7%) for the HPMC vehicle at the lowest exposure (10 µg/cm
2
), with better agreement at the higher exposures. Conversely, modeling accurately predicted rat dermal absorption (27.9%) as compared to in vivo rat results (21.7%) at the lowest exposure in HPMC, with diminished agreement at the higher exposures. As a first approximation, in silico estimates of dermal absorption are useful; however, these tend to be more variable than in vitro or in vivo measurements. TCVP dermal penetration measured in vitro was lower in 1% HPMC vehicle as compared to artificial sebum. For the 1% HPMC vehicle, in vitro rat dermal absorption was similar to data obtained for in vivo rats, giving confidence in the triple pack approach. In consideration of the triple pack approach, estimated human dermal absorption from 1% HPMC was ≤2%. Based upon excised human skin determinations directly, estimated human dermal absorption of TCVP from artificial sebum was ≤7%.
Methamidophos is a highly hazardous organophosphate and is known to cause an acute cholinergic toxidrome. Methamidophos use is not allowed in South Africa and therefore local data pertaining to ...methamidophos poisoning is very limited, with no paediatric clinical cases described. Methamidophos is an active metabolite of acephate, a commonly used organophosphate, registered for agricultural use in South Africa. We present a paediatric case of methamidophos poisoning with prolonged clinical effects. The patient experienced a prolonged cholinergic toxidrome lasting 10 days, with a period of near-full recovery during this time. We discuss the biological plausibility of the detected methamidophos being a byproduct of acephate. In addition, we highlight the importance of closer monitoring of patients with organophosphate poisoning in areas where acephate is commonly used.
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•Organophosphate.•Methamidophos.•Paediatrics.•Dermal absorption.•Prolonged cholinergic syndrome.
Heavy metals are naturally existing elements that have relatively high atomic weight and a minimum density five times the density of water. Heavy metals have extensive applications in industries, ...homes, agriculture and medicine, leading to their wide distribution in the environment. Most heavy metals are reported to be highly toxic. They also have numerous exposure routes, including ingestion, inhalation, and dermal absorption, subsequently inducing some health effects resulting from human and heavy metals contact. The implications of heavy metals with regards to children’s health have been noted to be more severe compared to adults. The element’s harmful consequences on children health include mental retardation, neurocognitive disorders, behavioral disorders, respiratory problems, cancer and cardiovascular diseases. Much attention should be given to heavy metals because of their high toxicity potential, widespread use, and prevalence. This review therefore examines the exposure routes and health effects of mercury (Hg), lead (Pb), chromium (Cr), cadmium (Cd), and barium (Ba) on children. In addition, their toxic mechanisms are elucidated.
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