The bioaccessibility of polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) in cooked plant and animal origin foods

Benchmark Dose for Dioxin Based on Gestational Diabetes Mellitus Using Coexposure Statistical Methods and an Optimized Physiologically Based Toxicokinetic Model

Dioxins are ubiquitous endocrine-disrupting substances, but determining the effects and benchmark doses in situations of coexposure is highly challenging. The objective of this study was to assess the relationship between dioxin andgestational diabetes mellitus (GDM), calculate the benchmark dose (BMD) of dioxin in coexposure scenarios, and derive a daily exposure threshold using an optimized physiologically based toxicokinetic (PBTK) model. Based on a nested case-control study including 77 cases with GDM and 154 controls, serum levels of 29 dioxin-like compounds (DLCs) along with 10 perfluoroalkyl acids (PFAAs), seven polybrominated diphenyl ethers (PBDEs), and five non-dioxin-like polychlorinated biphenyls (ndl-PCBs) were measured at 9-16 weeks of gestation. Bayesian machine kernel regression (BKMR) was employed to identify significant chemicals, and probit and logistic models were used to calculate BMD adjusted for significant chemicals. A physiologically based toxicokinetic (PBTK) model was optimized using polyfluorinated dibenzo-p-dioxins and dibenzofurans (PFDD/Fs) data by the Bayesian-Monte Carlo Markov chain method and was used to determine the daily dietary exposure threshold. The median serum level of total dioxin toxic equivalent (TEQ) was 7.72 pg TEQ/g fat. Logistic regression analysis revealed that individuals in the fifth quantile of total TEQ level had significantly higher odds of developing GDM compared to those in the first quantile (OR, 8.87; 95% CI 3.19, 27.58). The BKMR analysis identified dioxin TEQ and BDE-153 as the compounds with the greatest influence. The binary logistic and probit models showed that the BMD10 (benchmark dose corresponding to a 10% extra risk) and BMDL10 (lower bound on the BMD10) were 3.71 and 3.46 pg TEQ/g fat, respectively, when accounting for coexposure to BDE-153 up to the 80% level. Using the optimized PBTK model and modifying factor, it was estimated that daily exposure should be below 4.34 pg TEQ kg-1 bw week-1 in order to not reach a harmful serum concentration for GDM. Further studies should utilize coexposure statistical methods and physiologically based pharmacokinetic (PBTK) models in reference dose calculation.

Bioaccessibility and bioavailability of exogenous and endogenous toxic substances in traditional Chinese medicine and their significance in risk assessment

Scientific risk assessment of exogenous and endogenous toxic substances in traditional Chinese medicine (TCM) is of great significance. The present review comprises a comprehensive summary of progress in the health risk assessment of harmful exogenous substances in TCMs. Such substances include heavy metals, pesticide residues, biotoxins, and endogenous toxic components involving pyrrolizidine alkaloids. The review also discusses the strengths and weaknesses of various bioaccessibility and bioavailability models, and their applications in risk assessment. Future avenues of risk assessment research are highlighted, including further exploration of risk assessment parameters, innovation of bioaccessibility and bioavailability techniques, enhancement of probabilistic risk assessment combined with bioavailability, improvement of cumulative risk assessment strategies, and formulation of strategies for reducing relative bioavailability (RBA) values in TCMs. Such efforts represent an attempt to develop a risk assessment system that is capable of evaluating the exogenous and endogenous toxic substances in TCMs to ensure its safe use in clinics, and to promote the sustainable development of the TCM industry.

Behavior of diclofenac from contaminated fish after cooking and in vitro digestion

BACKGROUND

Seafood consumers are widely exposed to diclofenac due to the high contamination levels often present in aquatic organisms. It is a potential risk to public health due its endocrine disruptor properties. Limited information is available about diclofenac behavior after food digestion to enable a more realistic scenario of consumer exposure. This study aimed to evaluate cooking effects on diclofenac levels, and determine diclofenac bioaccessibility by an in vitro digestion assay, using commercial fish species (seabass and white mullet) as models. The production of the main metabolite 4'-hydroxydiclofenac was also investigated. Fish hamburgers were spiked at two levels (150 and 1000 ng g-1) and submitted to three culinary treatments (roasting, steaming and grilling).

RESULTS

The loss of water seems to increase the diclofenac levels after cooking, except in seabass with higher levels. The high bioaccessibility of diclofenac (59.1-98.3%) observed in both fish species indicates that consumers' intestines are more susceptible to absorption, which can be worrisome depending on the level of contamination. Contamination levels did not affect the diclofenac bioaccessibility in both species. Seabass, the fattest species, exhibited a higher bioaccessibility of diclofenac compared to white mullet. Overall, cooking decreased diclofenac bioaccessibility by up to 40% in seabass and 25% in white mullet. The main metabolite 4'-hydroxydiclofenac was not detected after cooking or digestion.

CONCLUSION

Thus, consumption of cooked fish, preferentially grilled seabass and steamed or baked white mullet are more advisable. This study highlights the importance to consider bioaccessibility and cooking in hazard characterization studies. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The Bioaccessibility and Bioavailability of Pentachlorophenol in Five Animal-Derived Foods Measured by Simulated Gastrointestinal Digestion

Pentachlorophenol (PCP) is a ubiquitous emerging persistent organic pollutant detected in the environment and foodstuffs. Despite the dietary intake of PCP being performed using surveillance data, the assessment does not consider the bioaccessibility and bioavailability of PCP. Pork, beef, pork liver, chicken and freshwater fish Ctenopharyngodon Idella-fortified by three levels of PCP were processed by RIVM and the Caco-2 cell model after steaming, boiling and pan-frying, and PCP in foods and digestive juices were detected using isotope dilution-UPLC-MS/MS. The culinary treatment and food matrix were significantly influenced (p < 0.05) in terms of the bioaccessibility and bioavailability of PCP. Pan-frying was a significant factor (p < 0.05) influencing the digestion and absorption of PCP in foods, with the following bioaccessibility: pork (81.37-90.36%), beef (72.09-83.63%), pork liver (69.11-78.07%), chicken (63.43-75.52%) and freshwater fish (60.27-72.14%). The bioavailability was as follows: pork (49.39-63.41%), beef (40.32-53.43%), pork liver (33.63-47.11%), chicken (30.63-40.83%) and freshwater fish (17.14-27.09%). Pork and beef with higher fat content were a key factor in facilitating the notable PCP bioaccessibility and bioavailability (p < 0.05). Further, the exposure of PCP to the population was significantly reduced by 42.70-98.46% after the consideration of bioaccessibility and bioavailability, with no potential health risk. It can improve the accuracy of risk assessment for PCP.

Tracing the Bioaccessibility of Per- and Polyfluoroalkyl Substances in Fish during Cooking Treatment

The effect of cooking on the contents of per- and polyfluoroalkyl substances (PFAS) in foods has been widely studied, but whether cooking-induced structural and chemical modifications in foods affect the oral bioaccessibility of PFAS remains largely unknown. In this study, three kinds of fishes with different fat contents were selected, and the bioaccessibility of PFAS during cooking treatment (steaming and frying) was evaluated using in vitro gastrointestinal simulation with gastric lipase addition. The results showed that related to their molecular structures, the bioaccessibility of an individual PFAS varied greatly, ranging from 26.0 to 108.1%. Cooking can reduce the bioaccessibility of PFAS, and steaming is more effective than oil-frying; one of the possible reasons for this result is that the PFAS is trapped in protein aggregates after heat treatment. Fish lipids and cooking oil ingested with meals exert different effects on the bioaccessibility of PFAS, which may be related to the state of the ingested lipid/oil and the degree of unsaturation of fatty acids. Gastric lipase boosted the release of long-chain PFAS during in vitro digestion, indicating that the degree of lipolysis considerably influences the bioaccessibility of hydrophobic PFAS. Estimated weekly PFAS intakes were recalibrated using bioaccessibility data, enabling more accurate and reliable dietary exposure assessments.

Bioavailability-based risk assessment of various heavy metals via multi-exposure routes for children and teenagers in Beijing, China

Assessing the health risks of sensitive population, such as children and teenagers, through multiple exposure routes (MERs) such as ingestion, inhalation, and dermal contact is critical for policy creation that protects or reduces exposure to pollutants for all populations. Heavy metal (HM) contents in food and environmental media in Beijing, capital of China, were collected. Furthermore, on the basis of considering the bioavailability of HMs, we evaluated the multiple environmental routes and health risks to HMs in children and teenagers of eight age groups (2-<3, 3-<4, 4-<5, 5-<6, 6-<9, 9-<12, 12-<15, and 15-<18) in Beijing, China by Monte Carlo simulation approach. The main findings are as follows: lead exposure in children aged 2-<3 years exceeds the exposure dose (0.3 μg·kg-1·d-1) of 0.5 point reduction in intelligence quotient. Moreover, children aged 2-<3 and 6-<9 years have relatively high non-carcinogenic risk (NCR) of 1.32 and 1.30, respectively. The carcinogenic risk (CR) for children aged 6-<9 and 9-<12 years is 2.73×10-6 and 2.39×10-6, respectively. Specifically, the contributions of oral ingestion, dermal contact, and inhalation to the NCR were 69.5%, 18.9%, and 11.6%, respectively. Moreover, the combined NCR contributions of copper, cadmium, mercury, and arsenic (As) were about 69.4%. The contributions of the above three routes to the CR were 93.4%, 4.1%, and 2.5%, in that order, with the largest CR contribution of As being about 92.0%. This study can provide new ideas for accurately assessing the exposure and health risks of HMs in the population, and we believe that it is necessary to update the national standards for food and soil based on the bioavailability of HMs.

Levels, enrichment characteristics and dietary intake risk of polychlorinated dibenzo-p-dioxin/furans in traditional smoked pork

The concentrations and TEQs of polychlorinated dibenzo-p-dioxin/furans (PCDD/Fs) in traditional smoked pork were significantly higher than those in raw pork, and mainly distributed in the surface layer. The main enriched congeners during traditional smoking were 2378-TCDF, 12378-PeCDF, 23478-PeCDF, 1234678-HpCDF, OCDF, 1234678-HpCDD and OCDD. The ability of each congener to transfer from the surface to the inner part was various. According to the dietary habits of local residents, PCDD/Fs in more than half of the traditional smoked pork samples posed a potential carcinogenic risk, and the risk in the surface samples were 1.02-10.2 times that of the corresponding inner samples. Some variables might be the important factors affecting the concentration of PCDD/Fs in smoked pork, such as the duration of smoking and the kind of fuel. It is recommended to achieve lower risk by reducing the consumption of smoked pork, especially the surface layer of smoked pork, and innovating traditional smoking technologies.

Bioaccessibility of per- and polyfluoroalkyl substances in food and dust: Implication for more accurate risk assessment

Humans are exposed to per- and polyfluoroalkyl substances (PFASs) mainly through oral exposure route, while little is known about their bioaccessibility (BC) in oral matrices. Here, the BC of 13 PFASs in simulated vegetable (VFs) and animal foods (AFs) as well as indoor dust was investigated using a physiology-based extraction test. The BC of PFASs in the AFs (78.5 ± 13.6 %) was distinctly higher than that in the VFs (60.6 ± 13.4 %), because high-saturated and long-chain fatty acids in the animal fat favored formation of more stable micelles. The BC of most long-chain PFASs was positively correlated with the protein content while negatively correlated with the carbohydrate content in the foods. The BC of polyfluoroalkyl phosphate diesters was negatively correlated with the lipid content. The BC of the very long-chain PFASs in the foods was 2.42-6.02 times higher than that in the dust, which might be attributed to their strong sequestration in dust. With the increase in bile salt concentration, the BC of PFASs in food increased and then remained constant, which was related to the changes in fatty acids and stability of the formed micelles. Comparing with the previous results obtained from animal study, the BC obtained in this study has the potential to predict PFAS bioavailability in food.

Serum levels of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in a sample of Lebanese pregnant women: The role of dietary, anthropometric, and environmental factors

Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are unintentionally produced, toxic environmental chemicals that persist for long years and bioaccumulate along the food chain, contaminating humans through diet. A particularly critical population subgroup is pregnant women given the adverse health effects on fetuses and newborns. Several anthropogenic sources of exposure to PCDD/Fs exist in Lebanon. Therefore, the aim of the present cross-sectional study is to measure the levels of PCDD/Fs in a sample of pregnant women in Lebanon and to explore potential associated factors. In this study, we measured serum concentrations of seven dioxins and ten furans, among 423 pregnant women recruited at delivery, using gas chromatography MS/MS. Among 269 participants, maternal sociodemographic information was collected including vicinity to landfills, incineration, pesticide use, industrial activity, and smoking. Anthropometric data were registered regarding pre-pregnancy body mass index (BMI), pre-pregnancy weight loss from restrictive diet, and gestational weight gain. Intake of major food groups generally related to PCDD/Fs was reported (fish, red meat, poultry, and dairy). Bivariate and multivariate analyses were performed to identify associations. PCDD/Fs were detected in 0 to 56.1% of the sample. Geometric mean concentrations were 75.5 (2.35) pg/g lipid and 2.25 (1.39) TEQ₂₀₀₅ pg/g lipid for total dioxins, and 2.66 (1.76) pg/g lipid and 0.34 (1.78) TEQ₂₀₀₅ pg/g lipid for total furans. Levels were relatively lower than levels previously observed in France, Germany, Mexico, Ghana, and Japan. Red meat consumption was the most consistently associated factor with a 2.38-2.57 fold increase in PCDD/F levels. Pre-pregnancy weight loss showed inverse associations with PCDD/F congeners. Vicinity to illegal incineration was also associated with a 2.32-2.43 fold increase in PCDD/F levels. In conclusion, results showed the importance of dietary, anthropometric, and environmental factors in the present sample's exposure to PCDD/Fs, in a region that contains anthropogenic sources of contamination.

Use of different endpoints to determine the bioavailability of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and polychlorinated biphenyls (PCBs) in Sprague-Dawley rats

Liver, fat (adipose tissue), blood, and feces are common endpoints used to determine the bioavailability of persistent organic pollutants (POPs). However, it is not known whether the bioavailability of each endpoints is comparable or whether there is a comprehensive endpoint that can be used for all congeners for the measurement of bioavailability. In this study, we observed the accumulation and distribution of 10 polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and 18 polychlorinated biphenyls (PCBs) in different organs of Sprague-Dawley (SD) rats and calculated the bioavailability based on feces, liver, and fat endpoints. Our results indicated that PCB 126, PCB 169, and 50% of PCDD/F congeners were mainly accumulated in the liver, with a bioavailability ranging from 28.9 to 50.6%. On the other hand, higher chlorinated (> 5 Cl) PCB congeners were mainly accumulated in adipose tissues, with a bioavailability ranging from 20.1 to 82.2%, while lower chlorinated (< 5 Cl) pollutants, such as 2,3,7,8-TeCDF, 2,3,7,8-TeCDD, 1,2,3,7,8-PeCDF, and PCB 28, 52, 77, 81, were likely metabolized over 36% in rats during the 8-week experimental period. If we considered metabolization (degradation) as a type of bioavailable process, then the fecal endpoint was a feasible option. However, if we considered the selective accumulation behavior of some congeners in different organs/tissues, then there was no single comprehensive endpoint suitable for all congeners. Lastly, female rats showed significantly higher PCDD bioavailability than male rats at low dose level (0.2 ng/100 g b.w./d); however, the difference in PCB bioavailability between female and male rats was not significant.

Accumulation and biotransformation of the novel vanillin-derived pesticide, vanisulfane, in laying hens after dietary exposure

Vanisulfane is a novel plant antiviral agent with promising prospects to prevent and control viral crop diseases. However, human health risk assessment after vanisulfane exposure from animal-derived food products remains limited. To gain insight into the accumulation and biotransformation of vanisulfane in livestock, laying hens were dietary exposed to ¹⁴C-vanisulfane. Although more than 80 % of the applied dose was observed in the excreta, vanisulfane and its metabolites accumulated in tissues, especially the liver and kidney, and was found to be transferred to eggs. A total of eight metabolites associated with both phase I and phase II metabolism were identified via ¹⁴C tracing and LC-QTOF-MS. Phase I metabolism included oxidation, hydroxylation, dechlorination and demethylation, and phase II metabolism was associated with sulfonic acid and glucuronide conjugation. The high percentages of metabolites in laying hens' tissues and organs, illustrated the active biotransformation of vanisulfane in vivo, which suggests that the marker residues of vanisulfane should consider its major metabolites. A digestive model was also used to determine the digestive fate of vanisulfane. This study improves our understanding of vanisulfane accumulation and biotransformation in laying hens, which will be helpful for risk assessments of foods derived from animals exposed to pesticides.

Exposure levels of PCDD/Fs and PCBs in human blood and the transplacental transfer characteristics in cord blood of newborns near the industrialized area

Mono-to octa-chlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) in pooled blood from the general population living near a typical industrialized area were investigated. Less chlorinated PCDD/Fs (mean: 2602 pg L^-1) were 7.5 times those of highly chlorinated ones (mean: 349 pg L^-1). The average ΣPCBs and Σdl-PCBs concentrations in human (cord) blood were 2741 (117) and 18 (0.31) ng L^-1, respectively. Higher concentrations of highly chlorinated PCDD/Fs were found in females than in males across different ages. The mean concentrations (and toxic equivalents (TEQs)) of PCDD/Fs were 282 (27) pg L^-1 in males and 312 (32) pg L^-1 in females. The concentrations of the PCDD/Fs and PCBs increased with age for both males and females, which might be caused by the long half-lives of these compounds and decreases in metabolic rates with age as the metabolic of nutrients, food, and also PCDD/Fs and PCBs would trend to slow. The TEQ of total PCDD/Fs and PCBs was higher in blood from orthopedics patients (107 pg L^-1) than other patients. This result may be associated with the bone density and pollutant bioaccumulation. In addition, total concentration of PCDD/Fs and PCBs in blood of women at reproductive age were 6.6 and 37 times the cord blood of newborns, respectively. Positive correlation of PCDD/Fs and PCBs especially for the higher chlorinated compounds between female and cord blood were discovered, which might be caused by the transplacental transfer characteristics and blood barrier for macromolecules and reduce the chemical exposure risks for newborns.

An aggregation-induced emission immunoassay for broad detection of polychlorinated biphenyls in chicken and crab

Polychlorinated biphenyls (PCBs) are persistent organic pollutants (POPs) with multiple variants, which may be harmful to human health by absorption and bioaccumulation. To ensure food safety, it is necessary to develop multi-residue immunoassays for broad recognition of PCBs. In this study, by mimicking the generic core structure of PCBs, three haptens have been designed and synthesized for monoclonal antibody (mAb) generation. A carboxylic acid derivative of PCB80 was a hapten that induced a mAb with broad recognition of PCBs. The results of ELISA further identified that the mAb could recognize 11 different kinds of PCBs; half-maximal inhibition concentrations (IC₅₀) ranged from 33.12 to 476.42 ng/mL. Subsequently, using aggregation-induced emission luminogen (AIEgen) nanobeads as the tracer for the output signal, the IC₅₀ value of the various PCBs was improved to 6.38-252.1 ng/mL. The limit of detection (LOD) varied from 0.32 to 42.15 ng/mL. Recoveries of 76.90-95.74% and intra-assay coefficients of variation of 8.5-14.4% were obtained with spiked chicken and crab meat samples. Matrix interference was eliminated by dilution, and no false-positive and false-negative results were observed. The developed assay provides a simple, broad-spectrum, and sensitive tool for detecting PCBs, with high-throughput possibilities for large-scale screening of PCBs in food.

Mechanisms Underlying the Impacts of Lipids on the Diverse Bioavailability of Per- and Polyfluoroalkyl Substances in Foods

Food is a major source of human exposure to per- and polyfluoroalkyl substances (PFASs), yet little is known about their bioavailability in food matrices. Here, the relative bioavailability (RBA) of PFASs in foods was determined using an in vivo mouse model. Pork, which had the highest lipid content, exhibited the greatest effect on bioavailability by increasing the RBAs of perfluoroalkyl acids (PFAAs) while reducing those of fluorotelomer phosphate diesters (diPAPs). During intestinal digestion of lipids, the bioaccessibility of PFAAs increased due to their greater partition into the stable mixed micelles. However, diPAPs were more likely to partition into the undigested oil phase due to their strong hydrophobicity. Both in vitro incubation and molecular docking results indicated that the PFAAs exhibited stronger binding affinities with mouse blood chylomicrons (CMs) than with diPAPs. Collectively, both lipid digestion in the intestine and the carrier effect of CMs played important roles in modulating the bioavailability of PFASs in food. More attention should be given to further evaluating the health risks of PFASs associated with the intake of high-lipid foods.

Polychlorinated dibenzo-p-dioxins and dibenzofurans in lotus from a lake historically polluted by the chlor-alkali industry: Occurrence, organ distribution and health risk from dietary intake

In this study, the organ distribution and exposure risk from dietary intake of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were investigated for lotus collected from Ya-er Lake, a lake in Hubei Province, Central China that was historically polluted by the chlor-alkali industry. The highest concentrations of PCDD/Fs were found in the main and fibrous lotus roots, with mean values of 48.9 ± 90.1 pg/g and 94.6 ± 143 pg/g, respectively. In all the investigated samples, Octa-CDD (OCDD) and Octa-CDF (OCDF) were the predominant congeners, at 26% and 17% of Σ₁₇ PCDD/Fs, respectively, followed by 1,2,3,4,6,7,8-HpCDF (9%). The distribution ratios of PCDD/Fs in adjacent lotus organs indicated that PCDD/Fs accumulated easily in edible organs, such as lotus seeds, membrane and leaves. The WHO-TEQ in the edible lotus organs and the probable daily intake (PDI) of lotus products by residents were calculated: the toxic equivalents in the lotus fruit parts reached a mean of 2 pg WHO-TEQ₂₀₀₅/g dw, and the mean weekly intake of lotus products for adolescents living around Ya-er Lake was 2.3 pg WHO-TEQ/kg bw/week. These results suggested that long-term consumption of lotus products from Ya-er Lake presents a health hazard to residents.

In vitro assessment of polychlorinated biphenyl bioaccessibility in meat: Influence of fat content, cooking level and consumer age on consumer uptake

In a risk assessment perspective, this work aims to assess the bioaccessibility of PCBs in meat. A standardised in vitro static digestion protocol was set up and coupled with extraction, clean-up and GC × GC-ToF/MS multianalyte method to monitor the fate of PCBs in meat during digestion. Starting with spiked meat, PCB bioaccessibility in 11% fat medium-cooked meat varied in adults from 20.6% to 30.5% according to congeners. PCB bioaccessibility increased to 44.2-50.1% in 5% fat meat and decreased to 6.2-9.1% and to 14.6-19.4% in digestion conditions mimicking infants and elderly, respectively. Intense cooking also decreased PCB bioaccessibility to 18.0-26.7%. Bioaccessibility data obtained with spiked meat were validated with measurements carried out in incurred meat samples. Finally, mean uptake distributions are obtained from a modular Bayesian approach. These distributions feature a lower mode when the fat content is higher, the meat is well-done cooked, and the consumers are older.

A comprehensive assessment of endocrine-disrupting chemicals in an Indian food basket: Levels, dietary intakes, and comparison with European data

Endocrine-disrupting chemicals (EDCs) in diet are a health concern and their monitoring in food has been introduced in the European Union. In developing countries, EDC dietary exposure data are scarce, especially from areas perceived as pollution hotspots, including industrialized countries like India. Several persistent organic pollutants (POPs) act as EDCs and pose a pressure to human health mainly through dietary exposure. In the present study, a range of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), dioxins and furans were measured in several food items collected from Indian urban (Delhi) and peri-urban (Dehradun) areas. Food basket contamination data were used to estimate EDC dietary exposure and compare it with that of the average European population estimated from available monitoring data. All the target contaminants were found in most food items, especially in dairies and meat products. OCPs were the main contributers to the measured EDC contamination. Food supplied to Delhi's markets had higher EDC contamination than that supplied to the peri-urban market in Dehradun. Despite lax compliance and control measures, Indian dietary exposure of OCPs and PBDEs were comparable with that of Europe and were lower for PCBs and dioxins. Higher meat consumption in Europe only partly explained this pattern which was driven also by the higher EDC residues in some European food items. A substantial part of endocrine disrupting potential in the diet derives from food and animal feeds internationally traded between developed and developing countries. With increasingly globalized food systems, internationally harmonized policies on EDC content in food can lead to better protection of health in both these contexts.

Bioaccessibility dependence of dietary exposure to dichlorodiphenyltrichloroethane and its metabolites and hexachlorocyclohexane isomers and their induced health risk: A case study in Beijing City, China

Bioaccessibility is essential for evaluating dietary intake of contaminants. However, there is insufficient information on the dependence of dietary intake and risk assessment of dichlorodiphenyltrichloroethane and its metabolites (DDXs) and hexachlorocyclohexane isomers (HCHs) on bioaccessibility. Here, we investigated the bioaccessibilities of DDXs and HCHs in various foods and their influences on assessing exposure in the residents of Beijing City, China. Forty-three major foods in five types (fruit, vegetables, cereals, aquatic food, and meat) were sampled, and the bioaccessibility of DDXs and HCHs was evaluated using a static in vitro gastrointestinal digestion model. The bioaccessibility of DDXs in different food types ranked in the order of meat > vegetables > fruit > cereals > aquatic food, with mean ± standard deviation values of 62.2 ± 22.1%, 20.5 ± 10.6%, 12.4 ± 3.66%, 11.2 ± 9.69%, and 10.7 ± 4.97%, respectively. The highest average bioaccessibility of HCHs was found in meat (83.4 ± 14.2%), followed by fruit (41.0 ± 12.5%), vegetables (37.6 ± 18.1%), aquatic foods (24.2 ± 9.22%), and cereals (8.73 ± 4.07%). The estimated daily intakes (EDI) of the sum of DDXs and the sum of HCHs based on the bioaccessible concentration were only about 17% and 55% of the total EDI based on the residual concentration, respectively. Meat was found to play a more important role in EDI after bioaccessibility correction. The proportion of the population with potential non-carcinogenic and carcinogenic risks markedly decreased when considering bioaccessibility. It was concluded that bioaccessibility should be integrated into dietary exposure evaluation.

Pesticides: formulants, distribution pathways and effects on human health - a review

Pesticides are commonly used in agriculture to enhance crop production and control pests. Therefore, pesticide residues can persist in the environment and agricultural crops. Although modern formulations are relatively safe to non-target species, numerous theoretical and experimental data demonstrate that pesticide residues can produce long-term negative effects on the health of humans and animals and stability of ecosystems. Of particular interest are molecular mechanisms that mediate the start of a cascade of adverse effects. This is a review of the latest literature data on the effects and consequences of contamination of agricultural crops by pesticide residues. In addition, we address the issue of implicit risks associated with pesticide formulations. The effects of pesticides are considered in the context of the Adverse Outcome Pathway concept.

Bioavailability Evaluation of Perchlorate in Different Foods In Vivo: Comparison with In Vitro Assays and Implications for Human Health Risk Assessment

Perchlorate in various foods continuously arouses public health concern. Bioavailability is a critical parameter to better estimate perchlorate exposure from diets. In this study, perchlorate bioavailability in five foods was determined in an in vivo mouse model and compared with in vitro bioaccessibility/bioavailability. The estimated in vivo perchlorate bioavailability for different foods ranged from 18.01 ± 4.53% to 45.60 ± 7.11%, with the order lettuce > pork > rice > milk powder > soybean. Moisture, fiber, and fat in foods were identified as critical factors affecting perchlorate bioavailability (correlation r = 0.71, 0.52, and -0.67, respectively). Linear regression analysis revealed that the in vitro perchlorate bioavailability determined using the Caco-2 cell model has the potential to estimate the in vivo perchlorate bioavailability in foods (R² = 0.67, slope = 1.33, and y intercept = 4.99). These findings provide insights into the effects of the food matrices on perchlorate bioavailability and could contribute to decrease the uncertainty regarding perchlorate dietary exposure risk assessment.

A review on in-vitro oral bioaccessibility of organic pollutants and its application in human exposure assessment

Generally, human oral exposure assessments of contaminants have not considered the absorption factor in the human gastrointestinal tract, thus overestimating human exposure and associated health risk. Currently, more researchers are adding the absorption factor into human exposure assessment, and bioaccessibility measured by in-vitro methods is generally replacing bioavailability for estimation because of the cheap and rapid determination. However, no single unified in-vitro method is used for bioaccessibility measurement of organic pollutants, although several methods have been developed for these pollutants and have shown good in vitro-in vivo correlation between bioaccessibility and bioavailability. The present review has focused on the development of in-vitro methods, validation of these methods through in-vivo assays, determination of factors influencing bioaccessibility, application of bioaccessibility in human exposure assessment, and the challenges faced. Overall, most in-vitro methods were validated using bioavailability, and better in vitro-in vivo correlations were obtained when absorption sinks were added to the digestion solution to mimic dynamic absorption of organic chemicals by small intestine. Incorporating bioaccessibility into the estimation of human exposure by oral ingestion significantly decreases the estimated exposure dose. However, more investigations on bioaccessibility of hydrophobic organic compounds are urgently needed because many challenges for in-vitro methods remain to be overcome.

Study on the bioaccessibility and bioavailability of perchlorate in different food matrices in vitro

Perchlorate, a persistent pollutant, interferes with iodine uptake by the thyroid. Perchlorate exposure mainly occurs through ingested food; understanding the bioaccessibility and bioavailability of perchlorate in foods facilitate more accurate human health risk assessments. An in vitro digestion/Caco-2 cell model was used for this research. The bioaccessibility of perchlorate in the control group, lettuce, rice and formula was 93.45%, 70.14%, 70.25%, and 63.68%, respectively. The bioavailability of perchlorate was as follows: control group, 43.45%; rice, 37.17%; lettuce, 35.13%; and formula, 30.72%. The absorptive apparent permeability coefficient (Papp) of the control, lettuce, rice, and formula was 30-101 nm/s, 32-65 nm/s, 54-161 nm/s, and 41-88 nm/s, respectively. The results suggested that the risk from perchlorate was overestimated only when considering the content of perchlorate in foods and that the presence of food matrices reduced perchlorate bioavailability by differing degrees.

Effects of cooking on oral bioaccessibility of PBDEs, MeO-PBDEs, and OH-PBDEs in fish (tilapia) and chicken egg

Human health concerns are rising with polybrominated diphenyl ethers' (PBDEs) analogues, methoxylated and hydroxylated PBDEs (MeO-PBDEs and OH-PBDEs), due to their occurrences in foods and greater potential toxicological effects than PBDEs. While the oral bioaccessibilities (BA%) of PBDEs in foods are available, such information on MeO-PBDEs and OH-PBDEs, and the effects of cooking on them have not been adequately addressed. The present study was conducted with fish and chicken egg as typical foods to assess the bioaccessibility (BA%) of PBDEs, MeO-PBDEs, and OH-PBDEs using the colon extended physiologically based extraction test and examine the effects of cooking processes (boiling, frying, and steaming) on them. The results showed that thermal degradation or transformation of the target compounds did not occur during boiling and frying of fish. The BA% of individual PBDEs, MeO-PBDEs, and OH-PBDEs were 20-51% for boiled fish, 11-20% for pan-fried fish, 15-77% for steamed egg, and 42-68% for pan-fried egg. Cooking decreased the BA% of all target compounds in fish due to protein denaturation. However, the BA% of OH-PBDEs in pan-fried egg were greater than those in steamed egg. In addition, the substituent groups of CH₃O- and OH- did not pose any effects on the BA% of BDE-47 in fish, but OH-group decreased its BA% in egg. These findings suggested that MeO-PBDEs and OH-PBDEs exhibited the similar oral BA% in fish to PBDEs, but the underlying mechanism for the effects of cooking on BA% of OH-PBDEs in egg needs to be further investigated.

Activation of six lipocalins genes' transcription under PCB18 stress in OsTIL-silenced Oryza sativa L

The lipocalins genes have been assigned for involving in the responses of organisms to various stress factors. The function of lipocalins under PCB18 stress was addressed by pathway complementation in the Oryza sativa L. OsTIL-silenced mutant. The growth of wild type (WT) and OsTIL-silenced mutant (MT) callus were suppressed by PCB18, and MT varieties were inhibited more seriously than WT varieties. Meanwhile, only WT varieties showed "Hormesis" effect. Compared with WT (3 day > 90.0%, 6 day ≤45.5%), MT varieties kept high removing efficiency by HPLC analysis. Varied gene transcription after OsTIL silencing was demonstrated between two varieties, especially obvious under PCB stress. Silenced OsTIL induced more protective gene transcriptions by qPCR analysis, OsVDE at 3 day, OsCHL, OsZEP1, OsZEP2 and OsUN at 6 day and OsZEP2 at 9 day. PCB18 stress further irritated these genes transcription in MT varieties. The defense stagy in WT varieties was that the transcriptions of lipocalins were inhibited to reduce PCB18 accumulation and toxicity. OsTIL could effectively limit PCB18 accumulation and toxicity. After TIL lacking, OsCHL, OsZEP1, OsZEP2 and OsUN in mutant were strongly evoked to against PCB stress. Remarkably, OsUN and OsZEP2 gene expressions were responded to PCB18 stress in both two varieties.

Magnetic solid-phase extraction as a novel method for the prediction of the bioaccessibility of polycyclic aromatic hydrocarbons

Chemical methods used to predict the bioaccessibility of hydrophobic organic compounds (HOCs) still need further development and improvement. In this work, magnetic solid-phase extraction (MSPE) based on poly(β-cyclodextrin)-coated magnetic polydopamine (Fe₃O₄@PDA@PCD) was first introduced to assess the bioaccessibility of polycyclic aromatic hydrocarbons (PAHs) in soils. Due to its good hydrophilicity and submicrometer scale, Fe₃O₄@PDA@PCD displayed a higher extraction rate for PAHs in an aqueous solution (equilibrium time < 5 min) than Tenax resin, which had an equilibrium time longer than 30 min. The merits of Fe₃O₄@PDA@PCD are beneficial to accelerate the desorption of PAHs from soil, especially for high molecular weight PAHs, in which the amounts extracted by Fe₃O₄@PDA@PCD were 1.2-2.8 times higher than those extracted by Tenax resin. The desorption kinetics data were well fitted with a two- or three-fraction model. The fitting results indicated that the MSPE method can be used to predict the bioaccessible fractions of PAHs. By comparing the prediction results obtained from the MSPE method with bioassays using earthworms, a significant linear correlation (R² = 0.98) with a slope statistically close to 1 was obtained. These results suggested that the MSPE method can act as a simple and efficient method to measure the bioaccessibility of PAHs in soil.

The Association between Seafood Intake and Fecundability: Analysis from Two Prospective Studies

Background: Seafood is an important source of omega-3 fatty acids, which have been associated with improved oocyte quality and embryo morphology in some studies. However, seafood is also a source of persistent organic pollutants and heavy metals, which may adversely affect fecundity. Previous studies of seafood intake and fecundity have generated inconsistent results. Methods: In two prospective cohort studies of 7836 female pregnancy planners from Denmark (Snart Foraeldre, n = 2709) and North America (PRESTO, n = 5127), we evaluated the association of dietary intake of total seafood and marine-sourced long-chain omega-3 fatty acids (eicosapentaenoic acid, docosahexaenoic acid, and docosapentaenoic acid) with fecundability. Participants completed a baseline questionnaire on sociodemographics, behavioral factors, anthropometrics, and medical history, and a food frequency questionnaire. Pregnancy status was updated bimonthly for up to 12 months or until reported conception. We estimated fecundability ratios (FRs) and 95% confidence intervals (CIs) using proportional probabilities regression models, adjusted for energy intake and other potential confounders. We restricted analyses to women with ≤6 menstrual cycles of attempt time at enrollment. Results: Intake of total seafood or marine-sourced long-chain omega-3 fatty acids was not appreciably associated with fecundability in either cohort (≥200 vs. <50 g/week total seafood: FR = 0.94, 95% CI: 0.79–1.10 in Snart Foraeldre; FR = 1.00, 95% CI: 0.90–1.13 in PRESTO; marine fatty acids: ≥90th vs. <25th percentile: FR = 1.00, 95% CI: 0.85–1.18 in Snart Foraeldre; FR = 0.97, 95% CI: 0.86–1.09 in PRESTO). In PRESTO, where we collected additional data on seafood preparation, we observed an inverse association between fecundability and fried shellfish (≥10 g/week vs. none: FR = 0.77, 95% CI: 0.61–0.98), but not unfried shellfish (≥20 g/week vs. none: FR = 0.98, 95% CI: 0.89–1.07); in Snart Foraeldre, there was no association with total shellfish intake. Conclusions: We found little association between seafood intake and fecundability overall, but greater intake of fried shellfish was associated with reduced fecundability among North American participants.

The Influence of Food on the In Vivo Bioavailability of DDT and Its Metabolites in Soil

Incidental soil ingestion is considered to be an important route of exposure to hydrophobic organic contaminants (HOCs), such as dichlorodiphenyl-trichloroethane (DDT). Contaminant ingestion often occurs during food consumption; however, knowledge on the influence of food on DDT bioavailability remains limited. In this study, the relative bioavailability (RBA) of soil DDTr (i.e., DDT and metabolites) was determined using an in vivo mouse model in the presence of eight kinds of food including rice, egg, pork, pear, soybean, bread, spinach, and milk powder. The values of DDTr-RBA ranged from 19.8 ± 10.9 to 114 ± 25.1%. DDTr-RBA was positively correlated with fat (r = 0.71) and negatively correlated with fiber (r = 0.63) content in food. A mechanistic study showed that fat enhanced micellarization and promoted the formation of chylomicron, which facilitated the dissolution and transport of DDTr in the intestinal tract. Bioaccessibility of DDTr was determined using a physiologically based in vitro method. The addition of lipase significantly improved the ability of the method to predict DDTr-RBA, indicating that the "fasted state" in vitro method required optimization for food scenarios. To the best of our knowledge, this is the first study to explore the mechanistic influence of food on DDTr-RBA and provide important knowledge on dietary approaches for reducing exposure to HOCs.

Is food type important for in vitro post ingestion bioaccessibility models of polychlorinated biphenyls sorbed to soil?

Soils are sorbents for many organic compounds and children consume relatively large amounts of soil. To improve the estimated health risks from this exposure pathway, we examined the role of co-ingested foods in determining the post-ingestion bioaccessibility (mobilization) of 18 polychlorinated biphenyls (PCBs) sorbed to 10 characterized soils. The bioaccessibility test system (DIN 19738, 2004) was an in vitro, 3-compartment, digestive tract containing salts, protein, and bile. Each soil was fortified with PCBs, then, digestive fluids appropriate to each compartment, were added sequentially. Next, digestive fluid and soil were seperated and PCB concentrations in both media were measured. This complete test system was then reduced to assess contributions of individual endogenous digestive fluid constituents (water, salts, pancreatin, bile, and mucin) and representative foods: protein (bovine serum albumin (BSA)), sugar (glucose), and fat (oleic acid). Then, the influence of increasing concentrations of BSA, glucose, and oleic acid was evaluated (individually) complete test systems. In a subset of the samples, solid phase microextraction (SPME) was used to measure freely dissolved PCBs. Across all treatments, percent soil organic carbon was the most influential bioaccessibility determinant, accounting for ≥87% of the explained variation. When evaluated individually, pancreatin, mucin, BSA, bile, and oleic acid each effectively increased PCB bioaccessibility and reduced freely dissolved PCB concentrations. This suggests competitive sorption of PCBs by organic constituents of the digestive constituents. Without sink material, intra-PCB mobilization differences were observed as freely dissolved PCB concentrations inversely correlated (p < 0.05) with their respective log K_ow's. When added to the complete digestive fluid, increasing oleic acid mass increased PCB bioaccessibility (p < 0.05), while adding more BSA or glucose did not (p > 0.05). This indicates that fat intake may be the sole consideration needed when modeling dietary contributions to bioaccessibility of soil sorbed PCBs.

Bioaccessibility of short chain chlorinated paraffins in meat and seafood

Bioaccessibility of short chain chlorinated paraffins (SCCPs), which is important for estimation of dietary exposure, has not been evaluated in previous studies. In the present study, we determined the bioaccessibility of SCCPs in meat (pork, beef and chicken) and seafood (fish, clams, and prawns) using the colon-extended physiologically based extraction test as an in vitro model. The bioaccessibility percentages (BAs) ranged from 33% to 84% in the fed state and from 41% to 63% in the unfed state. The BAs observed in the fed state were lower than in the unfed state in most samples, except for pork sample, which had the highest lipid content. This could be attributed to the effects caused by dietary components added in the fed state. The effects of lipid and protein in samples on bioaccessibility were investigated. In food with a high lipid content, like pork in this study, lipid was the main factor controlling SCCP bioaccessibility. In the other five foods, which had low-medium lipid contents, BA in the unfed state was positively correlated with lipid content (p < 0.05) and negatively correlated with the protein-to-lipid content ratio (p < 0.05). No significant relationships between lipid and protein content and BA were found in the fed state. As to SCCP congener groups, a positive relationship between the BAs of SCCP congener groups and their octanol-water partition coefficients (log K_ow) was found in pork sample in the fed state (p < 0.05). The BAs obtained in samples from fish, prawn, clam, and pork in the unfed state and that obtained in clam sample in the fed state were negatively correlated with log K_ow (p < 0.05). We calculated more accurate estimated dietary intakes of SCCPs using our SCCP bioaccessibility data. These results will contribute to more reliable dietary risk assessments of SCCPs.

Simultaneous detection of multiple hydroxylated polychlorinated biphenyls from biological samples using ultra-high-performance liquid chromatography with isotope dilution tandem mass spectrometry

We established a method for the separation and detection of nine hydroxylated polychlorinated biphenyls in whole blood and urine samples using ultra high performance liquid chromatography coupled with electrospray negative ionization tandem mass spectrometry. Clean-up procedures involved a filtration step, and optimization involved a pretreatment step consisting of a simple liquid-liquid extraction using hydrated silica-gel chromatography (5%). Nine hydroxylated polychlorinated biphenyls were separated on an ultra high performance liquid chromatography HSS T3 column using a gradient elution program of 2 mmol ammonium formate aqueous solution (A) and methanol (B). Recovery ranged from 84.0 to 105.4% for the nine different hydroxylated polychlorinated biphenyls in urine with three spiked levels of 0.1, 1, and 2 ng and from 73.5 to 98.6% for the blood with spiked levels of 0.2, 1, and 2 ng. The relative standard deviations were <8.7% (n = 6), and the limits of detection in urine and whole blood for the nine hydroxylated polychlorinated biphenyls were in the range of 1.5-4 and 20-100 pg/g, respectively. This analytical method may enable the simultaneous detection of various hydroxylated polychlorinated biphenyls from complex tissue matrices.

In vitro inhalation bioaccessibility for particle-bound hydrophobic organic chemicals: Method development, effects of particle size and hydrophobicity, and risk assessment

Bioaccessibility of particle-bound hydrophobic organic contaminants and related particle size effects are significant for assessing the potential human health risk via inhalation exposure, but have not been clearly evaluated. To fill this knowledge gap, the present study developed an in vitro method to estimate the inhalation bioaccessibility of particulate polycyclic aromatic hydrocarbons (PAHs) using simulated human lung fluids, i.e., a modified Gamble's solution (MGS) and artificial lysosomal fluid (ALF) with Tenax as the absorption media. Assay parameters, namely incubation time (10 d) and influence of filter use, were optimized for establishing the in vitro method. The results showed that the bioaccessibility of PAHs increased with increasing particle size, but other factors, such as total organic carbon and chemical hydrophobicity, also played a large role in the fate of these compounds. The results from this portion of the present study were then used to evaluate human health risk, which showed that the risk of these particle-bound PAHs by incorporating size-dependent PAHs bioaccessibility and deposition efficiency in the human respiratory tract into inhalation exposure risk calculations was reduced by >90% when compared to using total concentration. This suggested that the inhalation bioaccessibility and deposition efficiency of hydrophobic organic chemicals should be included in human health risk assessment.

Study of Factors Influencing the Bioaccessibility of Triazolone in Cherry Tomatoes Using a Static SHIME Model

Estimating the influence of bioaccessibility of pesticide residues in fruits and vegetables on dietary exposure is a challenge for human health risk assessment. This study investigated the bioaccessibility of pesticide residues in cherry tomatoes and contributing factors (digestion time, pH, solid/liquid ratio, and dietary nutrition) using an in vitro test simulating the human gastrointestinal tract. pH had the largest effect on triazolone precipitation in the simulated gastric intestinal juice, which had a significant impact on the bioaccessibility. The bioaccessibility of triazolone in the intestinal stage was slightly higher than that in the stomach stage, owing to bile salts and pancreatic enzymes present in the intestinal juice. The bioaccessibility of triazolone did not change significantly with digestion time. In the gastric stage, there was a logarithmic relationship between the bioaccessibility and solid/liquid ratio (R² = 0.9941). The addition of oil significantly changed the bioaccessibility in the gastrointestinal stage. Protein and dietary fiber only affected bioaccessibility in the stomach stage. Dietary nutrition can reduce the release of pesticides from fruits and vegetables into the stomach, sharply reducing the bioaccessibility, and the dietary exposure of pesticide residues in fruits and vegetables can be properly evaluated.

Thymoquinone is protective against 2,3,7,8-tetrachlorodibenzo-p-dioxin induced hepatotoxicity

We investigated changes in rat liver tissues following administration of thymoquinone (TQ) against 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induced hepatotoxicity. Fifty rats were assigned randomly to five groups of 10 as follows: control, corn oil, TCDD, TQ and TCDD + TQ. Biochemical and histopathological analyses were conducted on liver tissue. We found that 30 day TCDD administration caused histopathological changes in liver including thickening of Glisson's capsule, intracytoplasmic vacuolization in hepatocytes, sinusoidal dilation, vascular and sinusoidal congestion and inflammatory cell infiltration. TCDD administration increased malondialdehyde (MDA), total oxidant status (TOS), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) levels in rat liver tissue and reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and total antioxidant status (TAS) levels compared to all other groups. In the TQ treated group, GSH, SOD, CAT and TAS levels increased compared to all other groups. MDA, TOS, ALT, AST, ALP levels decreased compared to all other groups. Our histological findings were consistent with the biochemical findings. The oxidative and histologic effects of TCDD were eliminated by TQ treatment. TCDD administration caused oxidative stress in rat liver and TQ administered with TCDD prevented TCDD induced hepatotoxicity. TQ could be considered an alternative anti-TCDD toxicity agent.

Concentrations and Exposure Evaluation of Metals in Diverse Food Items from Chengdu, China

A total of 520 food samples belonging to 29 food types and 63 drinking water were collected in Chengdu market of China in 2014 to investigate the concentrations of 11 metals, and to assess the related exposure to the local consumers by estimating the hazard quotient and carcinogenic risk (CR). The results showed that metals concentrations in drinking water were below the limit values suggested by the Ministry of Health of the People's Republic of China, and FAO/WHO (Food and Agriculture Organization of the United Nations/World Health Organization). While As, Cd, and Cr were found at concentrations higher than the limit values in some of the foodstuffs. Children in Chengdu intake more metals compared to adults, with the same order of Mn > Zn > Cu > Sr > Cr > Ni > As > Cd > Pb > Co > Sb. Among all of the diverse food, rice, flour, and fish and seafood were the primary sources to intake metals for Chengdu residents. Residents in Chengdu are subjected to both carcinogenic and non-carcinogenic risks based on the calculated HI and CR values, especially for children. Finally, total daily metals intakes for both children and adults were calculated based on the current study and our previous studies, including consumption of food and drinking water and intake of outdoor and indoor dust. Dietary exposure is the predominant exposure route to metals for Chengdu residents, accounting for more than 75.8% of the total daily metals intakes for both children and adults.

Food contamination by PCBs and waste disposal crisis: Evidence from goat milk in Campania (Italy)

AIM

The study aims at investigating whether, and if so, to what extent the strong presence of urban and industrial waste in a territory may cause PCB contamination in goat milk produced therein.

METHODS

We compared PCB concentrations in goat milk from three different locations in the Campania region (Italy). One of the three locations, together with its surrounding area, has long suffered from illegal waste disposal and burning mainly by the so-called Ecomafia. The other locations, not involved in these illegal activities, allowed us to create a control group of goats with characteristics very similar to those of main interest.

RESULTS

In milk from the waste contaminated area we identified high PCB concentrations (six indicator PCBs amounted to 170 ng g^-1 on lipid weight, on average), whereas there was an almost total absence of such pollutants in milk from the control group. Concentrations of the six indicator PCBs were above the current European maximum residue limit fixed by the EU. At the same time, we found a lower average value of lipid content and a negative relationship between lipid content and PCB concentrations.

CONCLUSION

Evidence indicates the potential health risk for consumers living in areas involved in illegal dumping of waste.

Factors Affecting the Bioaccessibility and Intestinal Transport of Difenoconazole, Hexaconazole, and Spirodiclofen in Human Caco-2 Cells Following in Vitro Digestion

This study examined how gastrointestinal conditions affect pesticide bioaccessibility and intestinal transepithelial transport of pesticides (difenoconazole, hexaconazole, and spirodiclofen) in humans. We used an in vitro model combining human gastric and intestinal digestion, followed with Caco-2 cell model for human intestinal absorption. Bioaccessibility of three tested pesticides ranged from 25.2 to 76.3% and 10.6 to 79.63% in the gastric and intestinal phases, respectively. A marked trend similar to the normal distribution was observed between bioaccessibility and pH, with highest values observed at pH 2.12 in gastric juice. No significant differences were observed with increasing digestion time; however, a significant negative correlation was observed with the solid-liquid (S/L) ratio, following a logarithmic equation. R² ranged from 0.9198 to 0.9848 and 0.9526 to 0.9951 in the simulated gastric and intestinal juices, respectively, suggesting that the S/L ratio is also a major factor affecting bioaccessibility. Moreover, significant dose- and time-response effects were subsequently observed for intestinal membrane permeability of difenoconazole, but not for hexaconazole or spirodiclofen. This is the first study to demonstrate the uptake of pesticides by human intestinal cells, aiding quantification of the likely effects on human health and highlighting the importance of considering bioaccessibility in studies of dietary exposure to pesticide residues.

Effect of the Composition and Structure of Excipient Emulsion on the Bioaccessibility of Pesticide Residue in Agricultural Products

The influence of co-ingestion of food emulsions with tomatoes on the bioaccessibility of a model pesticide (chlorpyrifos) was studied. Emulsions were fabricated with different oil contents (0-8%), lipid compositions (medium chain triglyceride (MCT) and corn oil), and particle diameters (d₃₂ = 0.17 and 10 μm). The emulsions were then mixed with chlorpyrifos-contaminated tomato puree, and the mixtures were subjected to a simulated gastrointestinal tract (GIT) consisting of mouth, stomach, and small intestine. The particle size, surface charge, and microstructure of the emulsions was measured as they passed through the GIT, and chlorpyrifos bioaccessibility was determined after digestion. The composition and structure of the emulsions had a significant impact on chlorpyrifos bioaccessibility. Bioaccessibility increased with increasing oil content and was higher for corn oil than MCT, but did not strongly depend on oil droplet size. These results suggest that co-ingestion of emulsions with fruits or vegetables could increase pesticide bioaccessibility.

In-vitro bioaccessibility of five pyrethroids after human ingestion and the corresponding gastrointestinal digestion parameters: A contribution for human exposure assessments

Bioaccessibility is a crucial parameter in assessing the absorption of contaminants during the human digestive process, but few studies have involved the differences in the bioaccessibilities of pesticides. To investigate the mode of using the in vitro bioaccessibility to refine estimates of dietary exposure to pesticide residues, this study measured the bioaccessibilities of five pyrethroids in apples, and then, it modelled physicochemical predictors (gastrointestinal pH, digestive times, and the solid-liquid (S/L) ratio) of the bioaccessibilities of pyrethroids. Apple samples of gastric and intestinal phase digestive juices were obtained from an in vitro simulated digestion model. Our survey of in vitro digestion models found that the bioaccessibilities ranged from 4.42% to 31.22% and 10.58%-35.63% in the gastric and intestinal phases, respectively. A sharp trend similar to a normal distribution was observed between the bioaccessibilities and pH values. The bioaccessibility reached its highest value at a pH of 1.91 in the simulated gastric juice and did not significantly change with an increase of the digestive time. A significant negative correlation occurred between the bioaccessibility and S/L ratio, which followed a logarithmic equation. The correlation coefficients (R²) ranged from 0.9259 to 0.9831 and 0.9077 to 0.9960 in the simulated gastric and intestinal juice, respectively, suggested that both the pH value and S/L ratio were the main factors affecting the bioaccessibility. Furthermore, a combination of the acceptable daily intake (ADI) and bioaccessibility for human exposure assessments indicated the implication that traditional risk assessment using ADI may seriously overestimate the actual risk.

Chronic exposure of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces an obesogenic effect in C57BL/6J mice fed a high fat diet

Contaminant involvement in the pathophysiology of obesity is widely recognized. It has been shown that low dose and chronic exposure to endocrine disruptor compounds (EDCs) potentiated diet- induced obesity. High and acute exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a persistent organic pollutant (POP) and an EDC with anti-estrogenic property, causes wasting syndrome . However at lower doses, the TCDD metabolic effects remain poorly understood. We investigated the obesogenic effect during chronic exposure of TCDD at 1μg/kg body weight (bw)/week in adult C57BL/6J mice fed with a high fat diet (HFD) and exposed from 10 to 42 weeks old to TCDD or equal volume of vehicle by intragastric gavage. Under these conditions, TCDD was obesogenic in adult mice (7% in males and 8% in females), which was linked to fat mass. A sex effect was observed in the fat mass distribution in adipose tissue and in the hepatic triglyceride content evolution. In visceral fat pad weight, we observed a decrease (11%) in males and an increase (14%) in females. The hepatic triglyceride content increase (41%) in females only. TCDD failed to induce any change in plasma parameters regarding glucose and lipid homeostasis. Messenger ribonucleic acid (mRNA) levels involved in adipose tissue and hepatic metabolism, inflammation, xenobiotic metabolism and endocrine disruption were differently regulated between males and females. In conclusion, these results provide new evidence that dioxin, a POP and EDC can be obesogenic for adult mice with multi-organ effects.