AhR agonists screening and identification in indoor dust based on non-target chemical analysis by GC-Q-TOFMS and biological effect evaluation referring to ToxCast/Tox21 database.

Numerous studies reported the concentration of agonists of aryl hydrocarbon receptor (AhR) in indoor dust by target chemical analysis or the biological effects of activating the AhR by indoor extracts, but the major AhR agonists identification in indoor dust were rarely researched. In the present study, the indoor dust samples were collected for 7-ethoxyresorufin O-deethylase (EROD) assay and both non-targeted and targeted chemical analysis for AhR agonists by gas chromatography quadrupole time-of-flight mass spectrometry and gas chromatography-mass spectrometry analysis. Coupled with non-targeted analysis and toxicity Forecaster (ToxCast)/Tox21 database, 104 ToxCast chemicals were screened to be able to induce EROD response. The combination of targeted chemical analyses and biological effects evaluation indicated that PAHs, dibutyl phthalate (DBP) and Cypermethrin might be the important AhR-agonists in different indoor dust and mainly contributed in 1.84%-97.56 % (median: 26.62%) of total observed biological effects through comparing toxic equivalency quotient derived from chemical analysis with biological equivalences derived from bioassay. DBP and cypermethrin seldom reported in the analysis of AhR agonists should raise great concern. In addition, the present results in experiment of synthetic solution of 4 selected AhR-agonists pointed out that some unidentified AhR agonists existed in indoor dust.

A new border for circadian rhythm gene NFIL3 in diverse fields of cancer

The circadian rhythm disorder and abnormal expression of rhythm genes are related to many diseases, especially cancer. Rhythm gene NFIL3 is involved in energy metabolism and immune cell differentiation, and its aberrant expression is associated with metabolic diseases and inflammation. Previously, numerous studies have shown that aberrant NFIL3 expression is associated with tumorigenesis, progression, and chemotherapy resistance. For instance, NFIL3 performs as a nuclear transcription factor, impacts cell proliferation, represses apoptosis, and promotes cancer cell invasion and metastasis by regulating the transcription of target genes. In addition, NFIL3 expressed in cancer cells influences the type and proportion of infiltrated immune cells in the tumor microenvironment. Increased expression of NFIL3 induces the chemotherapy and immunotherapy resistance in cancer. In this review, we summarized the pathological functions of NFIL3 in tumorigenesis, cancer development, and treatment. The rhythm gene NFIL3 can be used as a promising target in cancer therapy in the future (AU)

The innovative model based on artificial intelligence algorithms to predict recurrence risk of patients with postoperative breast cancer.

Purpose: This study aimed to develop a machine learning model to retrospectively study and predict the recurrence risk of breast cancer patients after surgery by extracting the clinicopathological features of tumors from unstructured clinical electronic health record (EHR) data. Methods: This retrospective cohort included 1,841 breast cancer patients who underwent surgical treatment. To extract the principal features associated with recurrence risk, the clinical notes and histopathology reports of patients were collected and feature engineering was used. Predictive models were next conducted based on this important information. All algorithms were implemented using Python software. The accuracy of prediction models was further verified in the test cohort. The area under the curve (AUC), precision, recall, and F1 score were adopted to evaluate the performance of each model. Results: A training cohort with 1,289 patients and a test cohort with 552 patients were recruited. From 2011 to 2019, a total of 1,841 textual reports were included. For the prediction of recurrence risk, both LSTM, XGBoost, and SVM had favorable accuracies of 0.89, 0.86, and 0.78. The AUC values of the micro-average ROC curve corresponding to LSTM, XGBoost, and SVM were 0.98 ± 0.01, 0.97 ± 0.03, and 0.92 ± 0.06. Especially the LSTM model achieved superior execution than other models. The accuracy, F1 score, macro-avg F1 score (0.87), and weighted-avg F1 score (0.89) of the LSTM model produced higher values. All P values were statistically significant. Patients in the high-risk group predicted by our model performed more resistant to DNA damage and microtubule targeting drugs than those in the intermediate-risk group. The predicted low-risk patients were not statistically significant compared with intermediate- or high-risk patients due to the small sample size (188 low-risk patients were predicted via our model, and only two of them were administered chemotherapy alone after surgery). The prognosis of patients predicted by our model was consistent with the actual follow-up records. Conclusions: The constructed model accurately predicted the recurrence risk of breast cancer patients from EHR data and certainly evaluated the chemoresistance and prognosis of patients. Therefore, our model can help clinicians to formulate the individualized management of breast cancer patients.

Inhalation bioacessibility and lung cell penetration of indoor PM2.5-bound PAEs and its implication in risk assessment.

Several studies have evaluated the human exposure of phthalate esters (PAEs) in PM2.5 via inhalation route, however, inhalation bioaccessibility and the lung cell penetration of PAEs were barely considered in risk assessment. In the present study, PM2.5 samples collected from indoor environments were investigated for inhalation bioaccessibility of PAEs using two simulated lung fluids (gamble's solution (GMB) and artificial lysosomal fluid (ALF)). The results showed that the inhalation bioaccessibility of PAEs (except for diethyl phthalate) under healthy state (GMB: 8.9%-62.8%) was lower than that under the inflammatory condition (ALF: 14.5%-67.6%). Lung cell permeation and metabolism of three selected PAEs (diethyl phthalate, di(n-butyl)phthalate and di-2-ethylhexyl phthalate) was tested using equivalent lung cell (A549) model. The inhalation bioavailability obtained by combination of the bioaccessibility of PAEs in indoor PM2.5 and permeability data of A549 cell ranged from 11.7% to 51.1% in health condition, and 13.5%-55.0% in inflammatory state. The calibration parameter (Fc) based on the inhalation bioavailability was established in present study and could provide a reference for a more accurate risk assessment of PM2.5-bound PAEs.

A new border for circadian rhythm gene NFIL3 in diverse fields of cancer.

The circadian rhythm disorder and abnormal expression of rhythm genes are related to many diseases, especially cancer. Rhythm gene NFIL3 is involved in energy metabolism and immune cell differentiation, and its aberrant expression is associated with metabolic diseases and inflammation. Previously, numerous studies have shown that aberrant NFIL3 expression is associated with tumorigenesis, progression, and chemotherapy resistance. For instance, NFIL3 performs as a nuclear transcription factor, impacts cell proliferation, represses apoptosis, and promotes cancer cell invasion and metastasis by regulating the transcription of target genes. In addition, NFIL3 expressed in cancer cells influences the type and proportion of infiltrated immune cells in the tumor microenvironment. Increased expression of NFIL3 induces the chemotherapy and immunotherapy resistance in cancer. In this review, we summarized the pathological functions of NFIL3 in tumorigenesis, cancer development, and treatment. The rhythm gene NFIL3 can be used as a promising target in cancer therapy in the future.

Speciation and bioaccessibility of arsenic in rice under different cooking methods and its implication in risk assessment.

Numerous studies have studied the health risk assessment of human exposure to As or bioaccessible As via rice intake; however, the bioaccessibility of different As species in rice is seldom reported. In the present study, 31 rice samples were collected from markets or individual growers to investigate the speciation and bioaccessibility of As. Five different species (AsIII, AsV, DMA, MMA, and AsB) were detected in rice samples from different regions, among which AsIII accounted for the largest proportion (62.95% in average), followed by DMA and AsV. In addition, the cooking method could facilitate the release of As from rice into gastric and intestinal juice, and subsequently increase the bioaccessibility of As. The bioaccessibility of inorganic As in cooked rice ranged from 71.83 to 100%, and that of organic As ranged from 31.69 to 61.04%. Non-carcinogenic and carcinogenic risk assessment of children and adults exposure to As via rice intake considering the bioaccessibility of cooked rice was carried out. The target hazard quotient (THQ) of iAs and total As for children ranged from 0.21 to 1.61 and 0.48 to 2.26, respectively, while those for adults ranged from 0.12 to 0.88 and 0.26 to 1.23, respectively. Incremental lifetime cancer risk (ILCR) for children and adults ranged from 9.57 [Formula: see text] 10-5 to 7.25 [Formula: see text] 10-4 and 5.21 [Formula: see text] 10-5 to 3.95 [Formula: see text] 10-4, respectively. The results of risk assessment indicated that children would face a higher health risk than adults when they took the same type of rice as their staple food.

Adsorption of levofloxacin on natural zeolite: effects of ammonia nitrogen and humic acid.

The persistence of antibiotics in sewage treatment plants in recent years has become a serious problem. Meanwhile, humic acid and ammonia nitrogen are widely distributed in natural reservoirs and might influence the sorption, migration and transformation of antibiotics. In this study, natural zeolite (NZ) was evaluated as an adsorbent for the removal of levofloxacin (LEV). The physical and chemical properties of NZ before and after adsorption were characterized by various analytical techniques to develop the mechanism. The effects of ammonia nitrogen and humic acid (HA) on the interfacial behavior of LEV on NZ were explored. Comparative experiments revealed that LEV adsorption on NZ involved electrostatic interactions and ion exchange, and the adsorption processes were well fitted by the Langmuir isotherm model and pseudosecond-order kinetic model. The maximum experimental adsorption capacity of LEV was 22.17 mg·g-1 at pH 6.5. The presence of ammonia nitrogen and HA significantly suppressed the adsorption of LEV due to competitive adsorption, and the adsorption capacity decreased 58 and 46%, respectively. It is obvious that low concentrations of ammonia nitrogen and HA are conducive to improving the treatment effect of sewage. This study demonstrates that NZ is a promising and efficient material for LEV adsorption.

Study on sustainable developments in Guangdong Province from 2013 to 2018 based on an improved ecological footprint model.

Aiming at the ecological footprint model, the traditional trade adjustment method only considered the international trade process at the urban scale, ignoring the trade footprint generated by domestic trade and indirect trade in various products. This paper adopts the urban-scale ecological footprint model based on the macro-trade adjustment method to calculate the trade adjustment coefficient of biological products and the energy trade adjustment coefficient respectively to correct the trade footprint. The results showed that the per capita ecological deficit showed a straight upward trend, from 0.07351 hm2 in 2013 to 0.15472 hm2 in 2018. From 2013 to 2018, the per capita ecological footprint of Guangdong Province was greater than the per capita ecological carrying capacity, and the ecological economic system of Guangdong Province was in an unsustainable state. According to the trade ecological footprint, Guangdong Province was a completely foreign resource and service exporting city, which was consistent with Guangdong Province's own economic development direction; the analysis results of the ecological product trade footprint were more consistent with the current city positioning of biological resource products of each city, and the energy indirect trade footprint. The improved ecological footprint model could more accurately assess the true status of ecological vitality above the urban scale.

Elevated expression of the rhythm gene NFIL3 promotes the progression of TNBC by activating NF-κB signaling through suppression of NFKBIA transcription.

BACKGROUND: Epidemiological studies have confirmed that abnormal circadian rhythms are associated with tumorigenesis in breast cancer. However, few studies have investigated the pathological roles of rhythm genes in breast cancer progression. In this study, we aimed to evaluate the aberrant expression of 32 rhythm genes in breast cancer and detect the pathological roles and molecular mechanisms of the altered rhythm gene in regulating the progression of triple negative breast cancer (TNBC). METHODS: The aberrant expression of rhythm genes in breast cancer was screened by searching the GEPIA database and validated by using qRT-PCR and immunohistochemistry staining. Bioinformatics analysis combined with luciferase reporter experiment and chromatinimmunopercitation (ChIP) were used to investigate the molecular mechanism about aberrant expression of identified rhythm gene in breast cancer. The pathological roles of identified rhythm gene in TNBC progression was evaluated by colony formation assay, wound healing experiment, transwell assay, subcutaneous tumor formation and the mouse tail vein injection model through gain-of-function and loss-of-function strategies respectively. mRNA array, bioinformatics analysis, luciferase reporter experiment, ChIP and immunoflurescence assay were employed to investigate the key molecules and signaling pathways by which the identified rhythm gene regulating TNBC progression. RESULTS: We identified that nuclear factor interleukin 3 regulated (NFIL3) expression is significantly altered in TNBC compared with both normal breast tissues and other subtypes of breast cancer. We found that NFIL3 inhibits its own transcription, and thus, downregulated NFIL3 mRNA indicates high expression of NFIL3 protein in breast cancer. We demonstrated that NFIL3 promotes the proliferation and metastasis of TNBC cells in vitro and in vivo, and higher expression of NFIL3 is associated with poor prognosis of patients with TNBC. We further demonstrated that NFIL3 enhances the activity of NF-κB signaling. Mechanistically, we revealed that NFIL3 directly suppresses the transcription of NFKBIA, which blocks the activation of NF-κB and inhibits the progression of TNBC cells in vitro and in vivo. Moreover, we showed that enhancing NF-κB activity by repressing NFKBIA largely mimics the oncogenic effect of NFIL3 in TNBC, and anti-inflammatory strategies targeting NF-κB activity block the oncogenic roles of NFIL3 in TNBC. CONCLUSION: NFIL3 promotes the progression of TNBC by suppressing NFKBIA transcription and then enhancing NF-κB signaling-mediated cancer-associated inflammation. This study may provide a new target for TNBC prevention and therapy.

Inhalation bioacessibility and absorption of polycyclic aromatic hydrocarbons (PAHs) in indoor PM2.5 and its implication in risk assessment.

Inhalation bioaccessibility of polycyclic aromatic hydrocarbons (PAHs) in PM2.5 was assessed in numerous studies, however, the lung cell uptake and penetration of PAHs was seldom taken into account in risk assessment. In the present study, eighteen indoor PM2.5 samples collected from Guangzhou, China were analyzed for the inhalation bioavailability of PAHs combining the inhalation bioaccessibility and cell absorption of PAHs. Two simulated epithelial lung fluid mimicking the healthy condition (as represented by gamble's solution (GMB), pH = 7.4) and the inflammatory condition (as represented by artificial lysosomal fluid (ALF), pH = 4.5) were employed to evaluate the inhalation bioaccessibility. The results indicated that the bioaccessibility of PAHs under the inflammatory condition (1.28%-87.7%) was higher than that under healthy condition (0.88%-87.6%). Naphthalene, phenanthrene, pyrene and benzo[a]pyrene were selected for absorption assay of lung epithelial cells (A549). The absorption rate of PAHs ranged from 64.7 to 90.7% and it was inversely proportional to the number of aromatic rings. Taken together, the inhalation bioavailability based on the bioaccessibility of PAHs and the lung cell absorption ratio ranged from 9.9 to 56.9% under the healthy state, from 12.7 to 65.6% under inflammatory condition. The correction parameter (Fc) was thus established and can be used to improve the risk assessment of human exposure to PAHs via PM2.5 inhalation in future work.

Brominated flame retardants in home dust and its contribution to brominated flame retardants bioaccumulation in children hair.

Brominated flame retardants (BFRs) in house dust have raised significant concern around the world. However, few studies have reported the correlation between BFR concentrations in house dust and children's hair samples. In this study, BFR concentrations in house dust and children's hair were measured. Chemical analysis showed that the total concentrations of polybrominated diphenyl ethers (PBDEs) in house dust ranged from 334 to 4444 ng g-1, with a median of 442 ng g-1, and the concentrations in children's hair ranged from 352 to 655 ng g-1, with a median of 530 ng g-1. In addition, two alternative flame retardants, pentabromoethylbenzene (PBEB) and hexabromobenzene, were frequently detected in house dust and human hair. BDE209 was the most abundant PBDE congener detected in both house dust and children's hair. A significant correlation was found between the integrated PCA score of BFR concentrations in house dust and in children's hair (r2 = 0.31, P < 0.05), indicating the great contribution of house dust to the bodily burden of PBDEs in children. Risk assessment indicated that children's exposure to PBDEs via non-dietary intake of house dust should be recognized as an important exposure pathway.

Percutaneous Penetration and Metabolism of Plasticizers by Skin Cells and Its Implication in Dermal Exposure to Plasticizers by Skin Wipes.

Numerous studies focused on the human exposure to plasticizers via dermal contact; however, the percutaneous penetration of plasticizers was seldom considered in exposure assessment. In the present study, skin wipes of palms, back-of-hands, and forehead were collected from 114 participants (ages: 18-27). There was no significant difference between the levels of phthalates from palms and back-of-hand, while all phthalates collected from the forehead were significantly higher than those from palms and back-of-hand (p < 0.001); di(2-ethylhexyl)phthalate levels were substantially higher than other detected phthalates followed by di(n-butyl)phthalate and di(isobutyl)phthalate (DiBP), and for alternative plasticizers, bis-2-ethylhexyl terephthalate levels were substantially higher than acetyltributyl citrate and bis-2-ethylhexyladipate. Skin permeation and metabolism of phthalates was assessed using human skin equivalent models. The permeability coefficient (kp) values of phthalates were significantly negatively correlated with their log octanol-water partition coefficient (log Kow), while a significantly positive correlation was found between the log Kow and the cumulative amounts of phthalates in the cells. The proportion of phthalate intake via dermal exposure to skin wipes ranges from 1.3% (for dimethyl phthalate) to 8.6% (for DiBP) and suggests that dermal absorption is a significant route for adult phthalate exposure.

The comparison of transcriptomic response of green microalga Chlorella sorokiniana exposure to environmentally relevant concentration of cadmium(II) and 4-n-nonylphenol.

The transcriptomic response of green microalga Chlorella sorokiniana exposure to environmentally relevant concentration of cadmium(II) (Cd) and 4-n-nonylphenol (4-n-NP) was compared in the present study. Cd and 4-n-NP exposure showed a similar pattern of dys-regulated pathways. The photosystem was affected due to suppression of chlorophyll biosynthesis via down-regulation of Mg-protoporphyrin IX chelatase subunit ChlD (CHLD) and divinyl chlorophyllide a 8-vinyl-reductase (DVR) in Cd group and via down-regulation of DVR in 4-n-NP group. Furthermore, the reactive oxygen species (ROS) could be induced through down-regulation of solanesyl diphosphate synthase 1 (SPS1) and homogentisate phytyltransferase (HPT) in Cd group and via down-regulation of HPT in 4-n-NP group. Additionally, Cd and 4-n-NP would both cause the dys-regulation of carbohydrate metabolism and protein synthesis. On the other hand, there are some different responses or detoxification mechanism of C. sorokiniana to 4-n-NP stress compared to Cd exposure. The increased ROS would cause the DNA damage and protein destruction in Cd exposure group. Simultaneously, the RNA transcription was dys-regulated and a series of changes in gene expressions were observed. This included lipid metabolism, protein modification, and DNA repair, which involved in response of C. sorokiniana to Cd stress or detoxification of Cd. For 4-n-NP exposure, no effect on lipid metabolism and DNA repair was observed. The nucleotide metabolism including pyrimidine metabolism and purine metabolism was significantly up-regulated in the 4-n-NP exposure group, but not in the Cd exposure group. In addition, 4-n-NP would induce the ubiquitin-mediated proteolysis and proteasomal degradation to diminish the misfolded protein caused by ROS and down-regulation of heat shocking protein 40. In sum, the Cd and 4-n-NP could cause the same toxicological effects via the common pathways and possess similar detoxification mechanism. They also showed different responses in nucleotide metabolism, lipid metabolism, and DNA repair.

Dermal bioaccessibility of plasticizers in indoor dust and clothing.

Several studies indicate that human exposure to plasticizers via dermal pathway is not negligible, but the dermal bioaccessibility of phthalates and alternative plasticizers from the important environmental matrix including indoor dust and clothing and the importance weight of dermal exposure to those pollutants have been poorly studied. An in vitro physiologically based extraction test was employed to investigate the dermal bioaccessibility of target phthalates and alternative plasticizers from indoor dust and clothing. Temperature, incubation time, sweat/sebum ratio and solid/liquid ratio were selected to study their effects on the bioaccessibility. The bioaccessibility of Diethyl phthalates (DEP), dibutyl phthalate (DBP), bis-2-ethylhexyl phthalate (DEHP), Acetyl tributyl citrate (ATBC), bis-2-ethylhexyladipate (DEHA) and bis-2-ethylhexyl terephthalate (DEHT) in indoor dust were 66.20 ±â€¯1.93%, 94.27 ±â€¯1.31%, 80.37 ±â€¯8.09%, 75.02 ±â€¯2.12%, 94.50 ±â€¯3.42% and 74.09 ±â€¯3.79%, respectively, under the condition of 1:1 sweat/sebum ratio, 1/100 solid/liquid ratio (indoor dust), 1:1 area/area ratio (1:1, clothing) and 90 min incubation time at 36.3 °C which are chosen based on the experimental results and human physical conditions. DBP showed the highest bioaccessibility in all samples. The time course of the plasticizer release was fitted to a first-order one-compartment model. DBP showed the highest release rate (k1) calculated from the model, which was consistent with the bioaccessibility result. Risk assessment indicated that dermal exposure of DBP was an important exposure route, accounting for about 21.58% of total intake, and indoor dust was an important exposure media when considering the dermal bioaccessibility.

Comparison of sorption kinetics of PAHs by sorptive sinks and caco-2 cell and the correlation between bioaccessibility and bioavailability of PAHs in indoor dust.

Sorptive sinks are extensively used in the bioaccessibility of organic contaminants, but their suitability for simulating the intestinal cell is seldom reported. In the present study, the sorption efficiency of PAHs by sorptive sinks including silica, poly(ethylene-co-vinyl acetate) (polyE), tenax, and C18 were compared with that by caco-2 cells. The elimination rate constants of phenanthrene, fluoranthene, pyrene, benzo(a)pyrene by caco-2 cell were 0.0417 ±â€¯0.006 min-1, 0.0411 ±â€¯0.0074 min-1, 0.0362 ±â€¯0.006 min-1, and 0.0526 ±â€¯0.0037 min-1, respectively, which were more closely to that of silica and polyE compared to other materials. This indicated that these materials might be the preferable sorptive sinks to simulate absorption of PAHs by intestinal cells. The bioaccessibility of phenanthrene, fluoranthene, pyrene, benzo(a)pyrene in indoor dust ranged from 15.5-43.5%, 9.10-38.8%, 10.0-37.9%, and 6.00-21.9%, respectively, based on physiologically based extraction test (PBET) and the sorptive sinks added in the intestinal solution led to 1.17 to 8.47-fold enhancement of bioaccessibility. The correlation of in vivo PAHs relative bioavailability (RBA) and in vitro digestion bioaccessibility with or without the sorptive sinks of indoor dust were measured, and the results indicated that silica and polyE were more likely to predict PAHs RBA of indoor dust, which was consistent with the results of sorption kinetics assay. The present results indicate that silica and polyE have the potential to simulate caco-2 cell and the inclusion of these materials in the PBET is likely to predict PAHs RBA in indoor dust. Capsule: Silica and polyE were more likely to simulate absorption of PAHs by intestinal cells, and to predict PAHs RBA of indoor dust.

Synergistic effect of co-exposure to cadmium (II) and 4-n-nonylphenol on growth inhibition and oxidative stress of Chlorella sorokiniana.

Toxicological effect of freshwater algae co-exposure to Cd and 4-n-nonylphenol (4-n-NP) was seldom reported. In the present study, Chlorella sorokiniana was selected for testing the single and combined effect of Cd and 4-n-NP by detecting the growth inhibition and oxidative stress after exposure for 48 h, 72 h, and 96 h. The combined effects were evaluated by using toxic units (TU) method and concentration addition（CA）model. The synergistic effect of mixture on algal growth inhibition was both observed at 48 h and 72 h, and the additive effect was observed at 96 h. In addition, the significant alterations of superoxide, thiobarbituric acid reactive substances and antioxidant defenses (superoxide dismutase, catalase, glutathione) have been detected. It could be observed that the mixture predominantly lead to synergistic effects in superoxide induction, and the antagonistic effects in the GSH induction. A similar trend between the superoxide induction and growth inhibition were observed, which may indicate that the oxidative effects of Chlorella sorokiniana contributed to the growth inhibition after exposure to Cd and 4-n-NP. These findings may have important implications in the risk assessments of heavy metals and endocrine disruptors in the aquatic environment.

Comparison of in vitro digestion model with in vivo relative bioavailability of BDE-209 in indoor dust and combination of in vitro digestion/Caco-2 cell model to estimate the daily intake of BDE-209 via indoor dust.

There is limited information on the BDE-209 relative bioavailability (RBA) of indoor dust and the absorption of BDE-209 after in vitro digestion was seldom studied. In the present study, BDE-209 RBA in 6 household dust samples measured using an in vivo mouse model was compared to BDE-209 bioaccessibility determined using physiologically based extraction test (PBET) and solubility bioaccessibility research consortium method (SBRC) assays. BDE-209 RBA obtained ranged from 45.9 ± 16.1 to 96.0 ± 17.4% and exhibited a significant relationship with PBET gastric phase (r2 = 0.578, p = 0.080), small intestinal phase (r2 = 0.728, p = 0.031) and total BDE-209 bioaccessibility (r2 = 0.728, p = 0.031), which indicated PBET assay can serve as a surrogate to predict BDE-209 RBA to refine human health exposure. In addition, the absorption of BDE-209 by Caco-2 cell line was assessed. With the consideration of the corresponding bioaccessibility and absorption of BDE-209 by Caco-2 cell line, the human daily intake of BDE-209 via dust ingestion for adults and children was much lower than that estimated by total concentration.

In vitro digestion and absorption of BDE-28, -47, -99 and -153 in indoor dust and its implication in risk assessment.

The bioaccessibility of polybrominated diphenyl ethers (PBDEs) in indoor dust was estimated by a series of in vitro digestion methods. However, the absorption of PBDEs by intestinal cells after in vitro digestion was seldom studied. In the present study, the bioaccessibility of BDE-28, 47, 99 and 153 in indoor dust was firstly investigated by using the in vitro digestion method. Bioaccessibility in intestinal phase (BDE-28: 24.5-30.1%; BDE-47: 6.99-13.0; BDE-99: 1.61-14.2%; and BDE-153 5.97-24.4%.) was higher than that in gastric phase (BDE-28: 38.3-58.0; BDE-47: 9.62-30.9%; BDE-99: 9.71-24.3%; and BDE-153: 13.8-57.4%). The organic matter contents in indoor dust showed variable influence on the bioaccessibility of PBDEs. For the Caco-2 uptake assay, the BDE-28 showed greatest transport rate from medium to cell (Kmc: 0.525h-1), followed by -47, -99 and -153. The Kmc of PBDEs was significantly negative correlated with its corresponding KOW value. Similar pattern was found for the maximum uptake flux (Ju, max) and the transport rate from cell to medium (Kcm). The combination of bioacessibility and the absorption factor by Caco-2 cells could be used to estimate human intake of PBDEs via indoor dust would avoid overestimate the health risk.

Bioaccessibility of heavy metals in vegetables and its association with the physicochemical characteristics.

The bioaccessibilites of heavy metals in vegetables grown around a waste-incinerator site were estimated using the physiologically based extraction test (PBET) method, to assess potential health risk to the local consumers. The average gastric and intestinal bioaccessibilities of Cd, Cr, Cu, Ni, and Pb in vegetables varied within 3.2-9.4 and 0.8-5.3 %, 1.4-2.3 and 1.1-1.9 %, 25-46 and 13-26 %, 6.6-30 and 2.6-5.3 %, 11-29 and 7.1-23 %, respectively. Strong negative correlations were found between electrochemical potential (ΔE 0) and bioaccessibility for leaf mustard samples (r (2) = 0.857) and leaf lettuce samples (r (2) = 0.696). In addition, softness index (σp) and electrochemical potential (ΔE 0) exhibited a moderate but not significant relationship with bioaccessibilities on the basis of the multiple regression analysis (0.05 < p < 0.1). The total bioaccessible target hazard quotient (TBTHQ) of the five heavy metals was 2.5, with Pb being the major risk contributor. According to the TBTHQs of each group of vegetables, local consumers are experiencing adverse health effects by consuming most of the vegetables around waste-incinerator site.

Assessment of relative bioavailability of heavy metals in soil using in vivo mouse model and its implication for risk assessment compared with bioaccessibility using in vitro assay.

There is limited study to simultaneously determine the relative bioavailability of heavy metals such as Cd, Pb, Cu, Cr(VI), and Ni in soil samples. In the present study, the bioaccessibility of heavy metals using in vitro assay was compared with the relative bioavailability of heavy metals using in vivo mouse model. The bioaccessibility of heavy metals ranged from 9.05 ± 0.97 % (Cr) to 42.8 ± 3.52 % (Cd). The uptake profile of heavy metals in soil and solution samples in mouse revealed that the uptake kinetics could be fitted to a two-compartment model. The relative bioavailability of heavy meals ranged from 34.8 ± 7.0 % (Ni) to 131 ± 20.3 % (Cu). Poor correlation between bioaccessibility and relative bioavailability of heavy metals was observed (r (2) = 0.11, p > 0.05). The relative bioavailability of heavy metals was significantly higher than the bioaccessibility of heavy metals (p < 0.05). The present study indicated that the in vitro digestion method should be carefully employed in risk assessment.