•Transdermal permeation musks were investigated using an in vitro skin diffusion model.•The applied amounts of HHCB and AHTN did not affect percutaneous absorption rates.•The percutaneous absorption rate of HHCB and AHTN was approximately 11%.•Total estimated dermal intake of musks was markedly higher than total dermal uptake.•Dermal contact is the primary route of human exposure to synthetic musks.Synthetic musks, chemical constituents of personal care products, enter the human body through dermal contact. Elucidation of the mechanisms underlying transdermal permeation of synthetic musks should enhance our understanding of their uptake and distribution in human skin and allow accurate evaluation of associated human exposure. Here, the transdermal permeation dynamics and distribution of galaxolide (HHCB) and tonalide (AHTN) were investigated using an in vitro skin diffusion model. The transdermal permeation amounts of HHCB and AHTN increased rapidly during the first 6 h. The applied HHCB and AHTN amounts did not affect percutaneous absorption rates. HHCB and AHTN remained primarily in the stratum corneum, accounting for 70.0% and 70.3% of the totals during the 24-h period, respectively. The percutaneous absorption rate of both chemicals was ∼11%. HHCB, AHTN, musk ketone, musk xylene, and Musk-T were detected in 29 personal care products. The average total concentrations of the musks were 3990, 54.0, 17.7, and 9.8 μg g−1 in perfume, shampoo, lotion, and shower gel, respectively. Among the four product categories, HHCB was dominant (57.4%–99.6%), followed by AHTN. The data clearly indicate that polycyclic and nitro musks are most commonly used in personal care products. The total estimated dermal intake (51.6 μg kg−1bw day−1) was markedly higher than total dermal uptake (5.9 μg kg−1bw day−1) when percutaneous absorption rates of the chemicals were added into the calculation. Uptake of HHCB and AHTN via dermal contact of personal care products was significantly higher than that from dust inhalation calculated according to earlier literature data.

Exposure risks of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) via consumption of nine fish species from Taihu Lake in China and associated benefits, through ingestion of ω-3 polyunsaturated fatty acids (ω-3 PUFAs) in fish, were evaluated. The concentrations of PBDEs, PCBs and ω-3 PUFAs in fish from Taihu Lake ranged from 98.2 to 269 pg/g, from 279 to 1071 pg/g and from 0.9 to 2.0 mg/g, respectively. Omega-3 PUFAs accounted for 11.2–20.9% of the total fatty acid amounts. The PBDE/PCB contamination levels were moderate. To achieve the recommended intake of 250 mg/d of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), the associated PUFA and PBDE/PCB intakes from the species were estimated. Consumption of the species, to achieve the recommended EPA + DHA intake, did not exceed the allowable daily consumption of contaminated fish. Even though, consumers should make a sensible choice for fish species to maximise benefits and minimise risks.Highlights► PBDE/PCB levels and fatty acids in fish from Taihu Lake were analysed. ► Co-ingestion risk–benefit assessment of PBDEs/PCBs/ω-3 PUFAs by fish consumption. ► Fish consumption to achieve the recommended EPA + DHA intake was estimated. ► Consumers should make a sensible choice for fish species to maximise benefits.

Bioaccessibility of a contaminant in foods is the fraction of the contaminant mobilized from the food matrices during gastrointestinal digestion. In the present paper, the bioaccessibility of polybrominated diphenyl ethers (PBDEs) in 13 types of foods, including fish, meat, rice, flour, and vegetables, was determined using an in vitro digestion method. The bioaccessibility obtained ranged from 2.6% to 41.3%. It was found that the bioaccessibility of PBDEs exhibited positive correlations with fat and carbohydrate contents and negative correlations with protein and dietary fiber contents in the foods. Fat was the most important factor affecting the bioaccessibility of PBDEs. The mechanism underlying the correlations was discussed in view of partition of PBDEs between liquid and solid phases. To our knowledge, this is the first article systematically investigating the bioaccessibility of PBDEs in foods and demonstrating the influence of the food constituents on the bioaccessibility of PBDEs.

The factors affecting the bioaccessibility of polybrominated diphenyl ethers (PBDEs) in foodstuffs were investigated using a static in vitro model. The results showed that the gastrointestinal digestion increased the bioaccessibility of PBDEs in the intestinal solution. The incubation time significantly affected the bioaccessibility, which increased to about 25% in 4−6 h and reached equilibrium. The adsorption and release processes followed a Langmuir isotherm equation (R2 > 0.99). The concentrations of PBDEs in foodstuffs did not affect the bioaccessibility, while the ratios of liquid to the mass of foodstuffs had a significant effect when the ratios were less than 90. The bioaccessibility of PBDEs increased with increasing pH, reached a maximum at a pH of 7.3 ± 0.1, and then decreased in the intestine. To our knowledge, this is the first report demonstrating the digestive parameters playing such an important role for the bioaccessibility of PBDEs in foodstuffs. Even though in vitro tests are often conducted to study bioaccessibility, the extrapolation of such results to explain what is happening inside the highly dynamic environment of the human gastrointestinal tract is still sometimes uncertain and sometimes underestimated.

•PAHs in paired samples of maternal and umbilical cord serum, and placenta were study.•Low molecular weight PAHs were the predominant compounds in the three matrices.•PAHs can transfer from maternal serum to the fetal circulation.•Passive diffusion may control the transplacental transfer process of PAHs.•PAHs with lower KOW were more likely to transfer from mother to fetus via placenta.Prenatal exposure to polycyclic aromatic hydrocarbons (PAHs) is a high-priority public health concern. However, maternal to fetal transplacental transfer of PAHs has not been systematically studied. To investigate the transplacental transfer of PAHs from mother to fetus and determine the influence of lipophilicity (octanol-water partition coefficient, KOW) on transfer process, in the present study, we measured the concentrations of 15 PAHs in 95 paired maternal and umbilical cord serum, and placenta samples (in total 285 samples) collected in Shanghai, China. The average concentration of total PAHs was the highest in maternal serums (1290 ng g−1 lipid), followed by umbilical cord serums (1150 ng g-1 lipid). The value was the lowest in placenta samples (673 ng g-1 lipid). Low molecular weight PAHs were the predominant compounds in the three matrices. Increases in fish and meat consumption did not lead to increases in maternal PAH levels, and no obvious gender differences in umbilical cord serums were observed. The widespread presence of PAHs in umbilical cord serums indicated the occurrence of transplacental transfer. The ratios of PAH concentrations in umbilical cord serum to those in maternal serum (F/M) and the concentrations in placenta to those in maternal serum (P/M) of paired samples were analyzed to characterize the transfer process of individual PAHs. Most F/M ratios on lipid basis were close to one (range: 0.79 to 1.36), which suggested that passive diffusion may control the transplacental transfer of PAHs from maternal serum to the fetal circulation. The P/M and F/M values calculated on lipid basis showed that PAHs with lower KOW were more likely to transfer from mother to fetus via the placenta.Download high-res image (328KB)Download full-size image

Although early exposure to environmental pollutants may have important toxicological consequences, the mechanisms of transplacental transfer of synthetic musks are still not well understood. The objective of the present study was to learn the musk contaminations in three matrices, including maternal blood, umbilical cord blood, and breast milk; and investigate their placental transfer mechanisms.The concentrations of eight commonly used synthetic musks were measured in 42 paired samples (126 individual samples in total) of maternal serum, umbilical cord serum, and breast milk from Chinese women living in Shanghai.Musks were ubiquitously detected, especially galaxolide (HHCB) and musk xylene (MX). The total lipid-based concentrations were higher in umbilical cord sera (87.3 ng/g), but lower in breast milk (35.2 ng/g), compared with maternal serum concentrations (71.2 ng/g). There were significant correlations between maternal serum concentrations of HHCBs (HHCB and HHCB-lactone) and umbilical cord serum concentrations, and between maternal serum concentrations and breast milk concentrations (Spearman's rho = 0.338–0.597, p < 0.05), when outliers are excluded. The average transfer ratios of HHCB and HHCB-lactone between maternal sera and umbilical cord sera were >1. And the HHCB-lactone/HHCB ratio in maternal sera was higher compared with umbilical cord sera.Contamination levels were low compared with other regions and HHCBs were found to be the predominant constituents. No regional differences or age-related accumulations were observed. Our study suggests that prenatal exposure to HHCBs occurs and that transplacental transfer is the main route of exposure. Preferential accumulation in umbilical cord blood was observed. The results showed that transplacental transfer of HHCB did not correspond to passive diffusion since the transfer ratios were significantly different from 1. The transfer ratio for HHCB was also larger than that of HHCB-lactone, although HHCB has higher lipid solubility. Low fetal metabolism of HHCB was suggested by the HHCB-lactone/HHCB ratio in maternal and umbilical cord blood.

•Transepithelial transport mechanism of PBDEs in intestine tested using Caco-2 cells.•Passive diffusion dominated the transepithelial transport PBDEs in Caco-2 cell.•Transepithelial transport of PBDEs followed the pseudo-first-order kinetics process.•Trans-cell and trans-pore process is the rate-determining step in the PBDE transport.•Transporters of P-gp, MRP, BCRP, and OCTs participated in transepithelial transport.Oral ingestion plays an important role in human exposure to polybrominated diphenyl ethers (PBDEs). The uptake of PBDEs primarily occurs in the small intestine. The aim of the present study is to investigate the transepithelial transport characteristics and mechanisms of PBDEs in the small intestine using a Caco-2 cell monolayer model. The apparent permeability coefficients of PBDEs indicated that tri- to hepta-BDEs were poorly absorbed compounds. A linear increase in transepithelial transport was observed with various concentrations of PBDEs, which suggested that passive diffusion dominated their transport at the concentration range tested. In addition, the pseudo-first-order kinetics equation can be applied to the transepithelial transport of PBDEs. The rate-determining step in transepithelial transport of PBDEs was trans-cell transport including the trans-pore process. The significantly lower transepithelial transport rates at low temperature for bidirectional transepithelial transport suggested that an energy-dependent transport mechanism was involved. The efflux transporters (P-glycoprotein, multidrug resistance-associated protein, and breast cancer resistance protein) and influx transporters (organic cation transporters) participated in the transepithelial transport of PBDEs. In addition, the transepithelial transport of PBDEs was pH sensitive; however, more information is required to understand the influence of pH.Download high-res image (304KB)Download full-size image

Dichlorodiphenyltrichloroethane (DDT) and hexachlorocyclohexanes (HCHs) are widely detected in the environment, although they have been banned in China since 1980s. To better understand the route-specific daily uptake of the pesticides by humans, a total of 322 food, dust, and air samples were collected in Shanghai, China, during 2008–2011. The median concentrations were 0.2–126.6 and 0.03–1.6 ng/g wet weight for DDTs (DDT and its metabolites) and HCHs, respectively, in different types of foods. The values in dust (indoors and outdoors) were 5.7–29.8 and 1.3–5.4 ng/g, and 13.9 × 10− 3 and 2.6 × 10− 3 ng/m3 in air (gas + particle) for DDTs and HCHs, respectively. The daily uptake of a pesticide by humans was calculated via the pesticide intake multiplied by its uptake efficiency. The uptake efficiencies of DDTs and HCHs in food through human intestines were estimated using bioaccessibility measured via an in vitro method simulating the human gastrointestinal digestion process. The total daily uptakes of DDTs and HCHs through three routes (i.e., ingestion, inhalation, and dermal contact) were 79.4 and 4.9 ng/day, respectively, for children, and 131.1 and 8.0 ng/day, respectively, for adults. Ingestion via food and dust was the main route of human exposure to the pesticides, and the daily uptake of the pesticides via food consumption accounted for 95.0–99.2% of the total.Highlights► Levels of DDTs and HCHs in food, dust and air samples from Shanghai, China ► Bioaccessibility of DDTs and HCHs in food was measured using an in vitro test. ► Daily uptake of DDTs and HCHs via ingestion, inhalation, and dermal contacts ► Ingestion via food and dust was the main route of human exposure to DDTs and HCHs. ► DDTs/HCHs from food consumption accounted for 95.0–99.2% of the total daily uptake.