Occurrence and Dietary Intake of Organophosphate Esters via Animal-Origin Food Consumption in China: Results of a Chinese Total Diet Study

Pollution characteristics and health risk assessment of organophosphate esters in agricultural products from different regions of China

Organophosphate esters (OPEs) have been extensively utilized as flame retardants and plasticizers, raising significant concerns because of their persistence in the environment, mobility, and potential health risks. This study systematically analyzed the occurrence, spatial distribution, and health risks of 21 target OPEs in 232 agricultural product samples (including vegetables, fruits, grains, and animal products) collected from five regions in China: Shanghai, Liaoning, Qinghai, Sichuan, and Tibet. The results showed that the ∑11 OPEs concentrations ranged from ND (not detected) to 2381.79 μg/kg dw, with an average value of 160.79 μg/kg dw, reflecting the widespread presence of OPEs in these agricultural from the five regions. Significant regional differences were observed: Liaoning and Qinghai had the highest average concentrations, at 257.01 μg/kg dw and 245.85 μg/kg dw, respectively, while Sichuan and Tibet exhibited the lowest values, at 50.94 μg/kg dw and 43.11 μg/kg dw, respectively. Health risk assessments indicated that the HI∑ OPEs values in all regions were below the threshold of 1. Furthermore, the 95th percentile HI∑ OPEs value for grains in Liaoning approached 40 % of the threshold, with TDCIPP contributing 39 %, suggesting that the dietary exposure risks of OPEs remained a significant concern.

Plastic additives in the diet: Occurrence and dietary exposure in different population groups

A total diet study focused on exposure to plastic additives has been performed on 109 food samples. Plasticizers were detected in 85 % of analyzed samples with total concentrations ranging between not detected (nd) and 22.0 µg/g wet weight (ww). Non-phthalate plasticizers (NPPs), such as acetyl tributyl citrate (ATBC) or di(2-ethylhexyl) adipate (DEHA), were detected predominantly in baby foods (nd-3.38 µg/g ww) and meat (nd-15.0 µg/g ww), respectively. Significant differences (p ≤ 0.001) were observed across foods with different packaging types regarding the presence of ATBC and DEHA. ATBC was primarily detected in foods packaged in glass containers, meanwhile DEHA is mainly related to fresh food wrapped in plastic materials. Additionally, transference assays in selected ready to cook meals and fresh vegetables were performed, with NPPs exhibiting a higher transference from packaging to food than other compounds. The data obtained have been used for an assessment of estimated daily intake (EDI) of plastic additives in infants (6-12 months), toddlers (1-3 years), and adults (>18 years), resulting in values ranging 0.29-516 µg/kg body weight (bw)/day. Human risk related to baby food consumption, expressed as hazard quotients (HQs), was found with di(2-ethylhexyl) phthalate (DEHP) in the infant population sub-group.

Organophosphate esters and their metabolites in eggs from Vietnam

Data on the occurrence of organophosphate tri-esters (tri-OPEs) and their metabolites (di-OPEs) in hen's eggs are scarce. Therefore, 200 egg samples were gathered in 2023 in Hanoi, Vietnam and analysed by UHPLC-Q-Exactive HRMS. The majority of these compounds were detected, with tris(2-ethylhexyl) phosphate (0.10-2.7 ng/g wet weight (ww)) and trihexyl phosphate (0.08-2.3 ng/g ww) being the most prevalent tri-OPEs. Significant differences in tri-OPE profiles were observed in egg samples from battery-cage and free-range farming (p < .05). Despite egg levels ranging from 0.05 to 11.2 ng/g ww, Σdi-OPE accumulation in yolk and egg white was not significantly different in (p > .05). Among di-OPEs, dibutyl phosphate was found at the highest levels in the egg white, while bis(2-ethylhexyl) phosphate had the highest levels in yolk. There was no carcinogenic human health risk associated with OPEs in eggs (HQs <1).

Occurrence of Organophosphate Esters in Food and Food Contact Materials and Related Human Exposure Risks

Organophosphate esters (OPEs) are a class of anthropogenic chemicals that have long been used as plasticizers and flame retardants. Dietary intake is an important OPE exposure pathway for humans. Since OPEs are usually used as industrial additives in food contact materials (FCMs), OPEs can enter foods through contact to FCMs. This paper focused on FCM-related exposure risks in foods, summarizing the presence of OPEs in FCMs and foods, analyzing the migration of the OPEs from FCMs to food, and assessing the dietary exposure risk of the OPEs to humans. Overall, the levels of the OPE in FCMs were at higher levels than those in foods. Processed and packaged foods contained higher levels of OPEs than nonprocessed/fresh foods. The migration investigations revealed that OPEs can be more likely transferred from FCMs to foods under the conditions of higher temperature and longer exposure time. We hope that this work will extend our current knowledge of the apportionment of OPE sources in foods and highlight the existing research gaps.

Organophosphate Esters, Sperm Mitochondrial DNA Copy Number, and Semen Quality: A Longitudinal Study with Repeated Measurements

Toxicological studies revealed that exposure to organophosphate esters (OPEs) affects semen quality, but human evidence is controversial. Over a 3-month follow-up, 1,385 healthy young men provided 3,550 urine samples and 6,466 semen samples, which were determined for urinary OPE metabolite concentrations, sperm quality parameters, and sperm mitochondrial DNA copy number (mtDNAcn). Linear mixed models revealed inverse associations between diphenyl phosphate (DPHP) concentrations and sperm concentration [-3.81% (95% CI: -6.31, -1.24) per each 2-fold increment in exposure], total count [-4.07% (95% CI: -7.21, -0.76)], progressive motility [-0.55 (95% CI: -0.93, -0.17)], and total motility [-0.54 (95% CI: -0.91, -0.17)]; and between bis(2-butoxyethyl) phosphate (BBOEP) and diocresyl phosphate and di-p-cresyl phosphate (DoCP and DpCP) concentrations and sperm concentration [-3.61% (95% CI: -5.53, -1.58) and -3.27% (95% CI: -5.92, -0.48), respectively] and total count [-5.13% (95% CI: -7.53, -2.67) and -3.87% (95% CI: -7.21, -0.35), respectively]. These inverse associations persisted only for DPHP, DoCP and DpCP, and BBOEP measured during the epididymal storage period. Sperm mtDNAcn mediated 67.7% and 52.5%, respectively, of the associations between BBOEP and sperm concentration and total count [beta coefficient of average causal mediation effects = -0.15 (95% CI: -0.25, -0.07) and -0.18 (95% CI: -0.29, -0.08), respectively].

An assessment of the levels of emerging and traditional organophosphate ester flame retardants in dairy products in China and their combined dietary risks

A comprehensive survey was conducted by investigating 25 emerging and traditional organophosphate esters (OPEs) in 182 dairy products collected in China. The concentrations of total OPEs (ΣOPEs) ranged from 0.0261 to 1178 ng/g wet weight (ww) in all the dairy samples. The major contaminants were triethyl phosphate (proportion: 94 %) and tris(1-chloro-2-isopropyl) phosphate (proportion: 2 %). Among types of dairy products, the concentrations of ΣOPEs decreased in the following order: milk powder (mean: 80.8 ng/g ww, proportion: 86 %) > cheese (9.43 ng/g ww, 10 %) > milk tablets (2.72 ng/g ww, 3 %) > liquid dairy (1.05 ng/g ww, 1 %). The significant correlation between emerging and traditional OPEs suggests that they likely share similar sources or are used together in commercial applications. OPEs contamination was related to the OPEs properties, local OPEs production and application, and dairy types. For the general Chinese population, the average and high estimated daily intakes of ΣOPEs via dairy products were 31.5 and 83.6 ng/kg bw/day, respectively. Dairy exposure in toddlers and children were higher than other age groups. Although the high-exposure risk of ΣOPEs was 3.50 × 10-3, potentially toxic tris(1-chloro-2-isopropyl) phosphate accounted for 38 % of the total hazard quotients.

Occurrence of legacy and emerging organophosphate flame retardants (OPFRs) on silicone wristbands: Comparison within couples

Novel organophosphate flame retardants (OPFRs) are recently identified and highly detected in indoor dusts, but their personal exposure was not clear. Here, wristband was used to estimate non-dietary exposure to emerging OPFRs in comparison with legacy OPFRs in 93 adults in Beijing, China. Comparison of studies in wristband monitoring data showed a clear difference in profiles of legacy OPFRs between China and United States, where tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) was usually the dominant OPFR in the United States, but triphenyl phosphate has the highest contribution to total OPFRs in China. Five emerging OPFRs, including diethylene glycol bis(bis(2-chloroisopropyl) phosphate) (DEGBBCPP) and bis(2-ethylhexyl) phenyl phosphate (BEHPP), were detected in above 45 % of wristbands. The median concentration of DEGBBCPP (2.2 ng/g) was about three times higher than TDCIPP (0.76 ng/g), a legacy chloro-OPFR. Both emerging and legacy OPFRs were significantly correlated within 40 pairs of couples, suggesting major exposure in their homes. Wristbands from husbands had significantly higher tris(2-butoxyethyl) phosphate (TBOEP) and DEGBBCPP, while 2-ethylhexyl diphenyl phosphate (EHDPP) was significantly higher in wives' bands, suggesting gender-related exposure sources for these OPFRs.

Migration patterns of organophosphate esters from plastic food packaging simulants to foods: Donors, behaviours, and influencing factors

In recent years, organophosphate esters (OPEs) have been widely produced and used as flame retardants and plasticizer additives, posing significant ecological and health risks. Dietary intake is considered to be the primary route of human exposure to OPEs. Plastic food packaging materials are considered a crucial source for contamination of OPEs in food. However, the migration behaviour of OPEs from plastic food packaging materials into foods has received limited attention. In this study, we employed a novel method to prepare migration donors containing 13 kinds of OPEs. The migration behaviours of OPEs from food packaging simulants (polypropylene) to foods (full-fat milk powder) were simulated, and factors influencing the migration of OPEs were examined, including the properties of the target compounds, migration temperature, fat content of the migration receptors, and mass transfer mode. The results indicated that OPEs exhibited a significant migration tendency. Low molecular weight OPEs (< 300 Da) had faster migration efficiency compared to high molecular weight OPEs. The mean migration efficiencies of various OPEs showed a significant negative correlation with their molecular weights (p < 0.01) and a significant positive correlation with temperature (p < 0.01). Except for resorcinol bis(diphenyl phosphate) (RDP), which showed almost no migration, the mean migration efficiencies of other OPEs at 25 °C, 40 °C, and 60 °C were 3.1-37.5 %, 9.0-60.0 %, and 23.9-80.4 %, respectively. Most of the OPEs demonstrated higher migration efficiency in high-fat content food than low-fat content food. The migration of OPEs from food packaging simulants to foods primarily occurred through contact rather than gas-phase mass transfer. Overall, this study uncovers the migration behaviours of OPEs from food packaging simulants to foods and scrutinized the relevant factors influencing the migration. It is expected that the research in terms of the contamination control of OPEs in food will benefit from this work.

The disparities in health risks of multiple pollutants through soil and dietary exposure in a rural-urban area based on accessibility method

Rapid urbanization has resulted in disparities in environmental conditions for different communities in suburban area. This study presents a comprehensive investigation into the occurrence of pollutants in the soil and dietary food, and associated health risks in an urban-rural transitional area. The levels of potential toxic pollutants, notably metals, organophosphate esters (OPEs), and agrochemicals in surface soil and dietary food were evaluated. Higher levels of metals and OPEs were found in soils of industrial area, and agricultural soils had an elevated level of agrochemicals. The highest health risk was found for Chromium (Cr) which exceeded 1, indicating a high probability of adverse non-cancer effect to local residents. The levels of contaminants in food showed higher variability in community market and farmers' market than in supermarket, while higher levels of OPEs were found in food from supermarkets. The accessibility to fresh food mainly determined the differences in health risks of different communities. For dietary exposure, residents of industrial areas have higher levels of risk than other neighborhoods, mainly due to the possibility of exposure of foodstuffs with higher metal contents. In terms of market type, community markets mainly contributed to the comprehensive health risk through dietary exposure, especially for industrial and agricultural communities. The findings of this study provided further understanding of the spatial distribution of various contaminants as well as their health risks for different communities, which could guide the monitoring and management of potential toxic pollutants to safeguard public health in rural-urban transitional regions.

Organophosphate esters and their metabolites in Beijing total diets: Occurrence, time trend, and dietary exposure assessment

Organophosphate esters (OPEs) and their metabolites (mOPEs) are emerging pollutants. In this study, 18 OPEs and 10 mOPEs were measured in the 6th and 7th Beijing total diet studies (TDSs), and the dietary intakes of these pollutants by Beijing adults were estimated to assess related health concerns. Most OPEs and mOPEs had high detecting frequencies in both TDSs, which indicated that various foods in Beijing have been universally contaminated with OPEs and mOPEs. Statistical analysis further confirmed that the levels of both ∑OPEs and ∑mOPEs in the 7th Beijing TDS were significantly higher than those in the 6th study, indicating heavier contamination of both OPEs and their metabolites with time. Along with increasing OPE/mOPE contamination level and food consumption values, significant increases of EDIs were observed during the two studies, with the average EDIs of ∑OPEs increasing from 5.07 to 24.1 ng/kg bw/day, and that of ∑mOPEs increasing from 2.07 to 7.23 ng/kg bw/day. Although a comparison between EDIs and reference of doses (RfDs) indicated that current intakes of OPEs could still not cause significant health risks, the sharply increasing contamination levels and EDIs suggested the necessity to continuously monitor these emerging food contaminants.

Exploring organophosphate ester contamination and distribution in food: A meta-analysis

This study examines the food safety risk of organophosphate esters (OPEs) by analyzing data from 23 studies with 14,915 data points. We found EDP contamination highest in cereals, dairy, and meats, and TEHP most prevalent in vegetables and fruits, with contamination levels reaching 4.54 ng/g and 1.46 ng/g, respectively. Food processing influences OPE contamination through complex and multifaceted, akin to a "double-edged sword.", as meta-analysis and Principal Component Analysis (PCA) revealed. Estimated Dietary Intakes (EDI) identified vegetables and cereals as primary OPE sources, contributing 33.3% and 23.8% of total intake, with EDI values of 44.74 ng/kg bw/day and 32.25 ng/kg bw/day, respectively. Current exposure levels are within U.S. EPA safety thresholds (HQ < < 1), but the heightened risk to infants and children necessitates revising safety standards and ongoing monitoring.

Comprehensive dietary exposure assessment of the Chinese population to organophosphate esters (OPEs): Results of the sixth China total diet study

Organophosphate esters (OPEs) are emerging pollutants, while data on their occurrence in foods and human dietary intake are limited. Based on the 6th China total diet study conducted in 2016-2019, this study implemented a comprehensive survey of OPEs in plant-derived foods of cereals, potatoes, legumes, fruits, vegetables, and further assessed dietary exposure from both plant- and animal-derived food. The sum concentrations of 15 OPEs in the plant-derived samples ranged from 0.567 to 106 ng/g ww. 2-Ethylhexyl diphenyl phosphate (EHDPP) (median: 1.14 ng/g ww) had the highest level in plant-derived foods, with a proportion of 35.6% in the total median OPEs. Regional distribution analysis showed a higher contamination of OPEs in plant-derived food from northern area of China. Estimated dietary intakes (EDIs) of ∑OPEs for Chinese population were from 109 ng/kg bw/day in Beijing to 1164 ng/kg bw/day in Gansu province, with mean and median of 296 and 222 ng/kg bw/day, respectively. Although animal-derived foods had higher levels of OPEs, plant-derived foods, specifically cereals, was the major source of dietary OPE intake. The EDIs were much lower than reference doses, which suggested the intakes of OPEs via food consumption could not cause significant health risks to the Chinese population at present.

Organophosphate Esters in Raw Cow Milk and Cow's Drinking Water and Feed from China: Occurrence, Regional Distribution, and Dietary Exposure Assessment

Organophosphate esters (OPEs) have been widely produced and used, while little is known about their occurrence in the food chain and potential sources. In this study, raw cow milk, cow drinking water, and feed were collected from pastures across China, and OPEs were tested to explore the occurrence and transmission of OPEs in the food chain and to further assess daily OPE intakes for cows and humans via certain food consumption. The median level of ∑OPEs (sum of 15 OPEs) in raw milk was 2140 pg/mL, and tris(1-chloro-2-propyl) phosphate (TCIPP) was the most abundant OPE. Levels of OPEs in water were lower than those in raw milk except for triethyl phosphate (TEP), while levels of most OPEs in feed were significantly higher than those in raw milk (adjusted by dry weight). The estimated dietary intake of OPEs via feed for cows was 2530 ng/kg bw/day, which was much higher than that via water (742 ng/kg bw/day), indicating that feed was a more critical exposure source. For liquid milk consumers, the high-exposure (95th) estimated daily intakes (EDIs) of ∑15OPE were 20 and 7.11 ng/kg bw/day for 3-17 years and adults, respectively, and it is obvious that cows had much heavier OPE intake. Finally, the calculated hazard indexes (HIs) suggested that the intake of OPEs via cow milk consumption would not pose significant health risks to the Chinese population.

Nationwide Investigation on Organophosphate Flame Retardants in Tea from China: Migration from Packaging Materials and Implications for Global Risk Assessment

In this study, we measured 15 common organophosphate flame retardants (OPFRs) in six categories of tea samples across China. OPFRs were found in all the tea samples, with the total concentrations of OPFRs (∑OPFRs) at 3.44-432 ng/g [geometric mean (GM): 17.6 ng/g]. Triphenyl phosphate (TPhP) was the dominant OPFR, accounting for 39.0-76.2% of ∑OPFRs across all tea categories. The potential factors influencing the residual OPFRs in tea were thoroughly examined, including the agricultural environment, fermentation, and packaging of teas. Tea packaging materials (TPMs) were then identified as the primary sources of OPFRs in teas. The migration test revealed that OPFRs with lower molecular weights and log Kow values exhibited a higher propensity for facilitating the migration of OPFRs from TPMs to teas. The estimated daily intakes of OPFRs from teas were relatively higher for the general populations in Mauritania, Gambia, Togo, Morocco, and Senegal (3.18-9.79 ng/kg bw/day) than China (3.12 ng/kg bw/day). The health risks arising from OPFRs in Chinese teas were minor. This study established a baseline concentration and demonstrated the contamination sources of OPFRs in Chinese tea for the first time, with an emphasis on enhancing the hygiene standards for TPMs.

Occurrence of bisphenol analogues and their conjugated metabolites in foodstuff

Bisphenol analogues (BPs) are prevalent in diverse foodstuff samples worldwide. However, the occurrence of conjugated bisphenol A (BPA) and bisphenol S (BPS) metabolites in foodstuff remains poorly understood. This study analyzed eight BPs, and four conjugated BPA and BPS metabolites, in three animal-derived foodstuff and five plant-derived foodstuff samples from China. Results showed that fish foodstuff (9.7 ng/g ww) contained the highest mean concentration of BPA, followed by rice (5.1 ng/g ww) and beans foodstuff (3.6 ng/g ww). BPA-sulfate had higher mean concentrations than BPA-glucuronide in different foodstuff categories, except that in eggs foodstuff (p < 0.05). Compared with other foodstuff items, fish (3.4 ng/g ww) and vegetable (1.6 ng/g ww) foodstuff samples exhibited comparatively higher mean concentrations of BPS. Mean concentrations of BPS-sulfate were consistently higher than BPS-glucuronide in vegetables, meats, and fish foodstuff (p < 0.05). BPA contributed the major total dietary intake (DI) of BPs, with the mean DI of 435 ng/kg bw/day for women and 374 ng/kg bw/day for men, respectively. To our knowledge, this study is the first to investigate the occurrence of conjugated BPA and BPS metabolites in foodstuff, which enhances our comprehension of the origins of these conjugated metabolites in the human body.

Organophosphate esters in milk across thirteen countries from 2020 to 2023: Concentrations, sources, temporal trends and ToxPi priority to humans

Recent increases in organophosphate ester (OPE) application have led to their widespread presence, yet little is known about their temporal trends in food. This study collected milk samples from 13 countries across three continents during 2020-2023, finding detectable OPEs in all samples (range: 2.25-19.7; median: 7.06 ng/g ww). Although no statistical temporal differences were found for the total OPEs during the 4-year sampling campaign, it was interesting to observe significant variations in the decreasing trend for Cl-OPEs and concentration variations for aryl-OPEs and alkyl-OPEs (p < 0.05), indicating changing OPE use patterns. Packaged milk exhibited significant higher OPE levels than those found in directly collected raw unpackaged milk, and milk with longer shelf-life showed higher OPE levels, revealing packaging material as a contamination source. No significant geographical differences were observed in milk across countries (p > 0.05), but Shandong Province, a major OPE production site in China, showed relatively higher OPE concentrations. The Monte Carlo simulation of estimated daily intakes indicated no exposure risk from OPEs through milk consumption. The molecular docking method was used to assess human hormone binding affinity with OPEs, amongst which aryl-OPEs had the highest binding energies. The Toxicological-Priority-Index method which integrated chemical property, detection frequency, risk quotients, hazardous quotients and endocrine-disrupting effects was employed to prioritize OPEs. Aryl-OPEs showed the highest scores, deserving attention in the future.

Emerging organophosphite and organophosphate esters in takeaway food and the implications for human exposure

Takeaway food has become a prominent component of the diet in urban areas of China, especially for young people. Although dietary intake is a major pathway to contaminants for human exposure, studies on emerging organophosphite antioxidants (OPAs) and organophosphate esters (OPEs) in food are scarce. Here, we investigated four OPAs and 19 OPEs in takeaway foods (n = 99) and paired takeaway food packaging (n = 50) in China. AO168=O (mean: 14.9 ng/g ww), TPPO (mean: 1.05 ng/g ww), and TCIPP (mean: 0.579 ng/g ww) were dominant in the takeaway food. Some OPEs had significant correlations in takeaway food. Emerging OPAs and OPEs in takeaway food varied significantly depending on the packaging materials and food types. AO168 and AO168=O were widespread in the paired takeaway food packaging. The migration efficiencies of emerging OPAs and OPEs were low in takeaway food packaged in aluminum foil. Although the actual contamination of emerging OPAs and OPEs in takeaway food significantly differed from those of in food simulants migrated from paired takeaway food packaging, the results imply that food itself and takeaway food packaging are potential contamination sources of emerging OPAs and OPEs in takeaway food. The average estimated dietary intakes of emerging OPAs and OPEs were 465 ng/kg body weight (bw)/day and 91.9 ng/kg bw/day, respectively. The exposure risk of emerging OPAs and OPEs through takeaway food intake is low in China.

Discovery and occurrence of organophosphorothioate esters in food contact plastics and foodstuffs from South China: Dietary intake assessment

A recent study revealed the presence of non-pesticide organothiophosphate esters (OTPEs) - precursors to organophosphate esters (OPEs) contaminants - in river water. Since OPEs have demonstrated adverse reproductive outcomes in humans, this accentuates the urgency to explore the prevalence of non-pesticide OTPEs in other potential human exposure matrices. In this study, a nontarget screening method based on high-resolution mass spectrometry was used to identify OTPEs in food contact plastic (FCP) samples collected from South China. O,O,O-triphenyl phosphorothioate (TPhPt) and O,O,O-tris(2,4-di-tert-butylphenyl) phosphorothioate (AO168 = S) were unequivocally identified (Level 1), while O,O-di(di-butylphenyl) O-methyl phosphorothioate (BDBPMPt) was tentatively identified (Level 2b, indicating probable structure based on diagnostic evidence). Among n = 70 FCP samples, AO168 = S emerged with the highest detection frequency and median concentration of 74 % and 111 ng/g, respectively. Significant Pearson correlations were observed in log-transformed peak areas of AO168 = S and TPhPt in FCPs with their respective oxons, respectively. Occurrences of AO168 = S and TPhPt were further investigated in n = 100 foodstuff samples using a market basket method. AO168 = S and TPhPt exhibited detection frequencies of 43 % and 44 % in all food items with mean concentrations of 2.17 ng/g wet weight (ww) (range: <0.53-67.8 ng/g ww) and 0.112 ng/g ww (range: <0.006-2.39 ng/g ww), respectively. The highest mean concentrations for AO168 = S and TPhPt were found in vegetables (4.62 ng/g ww) and oil (3.00 ng/g ww), respectively. The median estimated daily intakes (EDIs) of AO168 = S and TPhPt via diet were calculated as 10.4 and 1.51 ng/kg body weight/day, respectively. For AO168 = S, only meat and vegetables contributed to the median EDI, whereas for TPhPt, oil was identified as the principal contributor to the median EDI. This study for the first time evaluated human exposure to OTPEs via diet, providing new insights to overall human exposure to OPEs.

High-resolution mass spectrometry-based screening and dietary intake assessment of organophosphate esters in foodstuffs from South China

Organophosphate esters (OPEs) are a group of emerging contaminants with widespread environmental occurrence, yet research on their occurrence in foodstuffs is limited. We collected 100 foodstuff samples in South China using a market basket method, and analyzed food extracts for the presence of OPEs and organophosphite antioxidants (OPAs) by suspect and nontarget screening through high-resolution mass spectrometry. Our analysis resulted in the identification of 30 OPEs, comprised of 25 OPEs with a confidence level (CL) of 1 (unequivocal identification using standards) and five OPEs with CL = 2b (probable structure based on diagnostic evidence). Interestingly, 11 of these identified OPEs had not been previously reported in food. No OPA was identified. The occurrence of identified OPEs within the food samples was further investigated. The highest median concentration of OPEs in all food samples was reached by tris(2-chloroisopropyl) phosphate (TCPP) (1.55 ng/g ww, range < 0.74-12.0 ng/g wet weight (ww)). Cereals demonstrated the highest median concentration of the cumulative 30 OPEs. Tris(2-chloroethyl) phosphate (TCEP), TCPP, and triethyl phosphate (TEP) predominantly contributed to OPEs contamination in most food categories. Eight OPEs, namely TEP, tris(2-ethylhexyl) phosphate (TEHP), TCEP, triphenyl phosphate (TPhP), 2-ethylhexyl diphenyl phosphate (EHDPP), bis(2-ethylhexyl) phenyl phosphate (BEHPP), resorcinol bis(diphenyl phosphate) (RDP), and methyl diphenyl phosphate (MDPP) exhibited significantly higher concentrations in the processed group as compared to non-processed group, suggesting that food processing may result in contamination of these OPEs. The median sum of estimated dietary intake (ΣEDI) of all OPEs was determined to be 161 ng/kg body weight/day. Cereals (38.5 %) and vegetables (23.5 %) were the predominant food categories contributing to ΣEDI, and TEP (29.0 %), TCEP (20.2 %), and TCPP (18.3 %) were three major OPEs contributing to ΣEDI. This study for the first time offered a comprehensive overview of OPE species and revealed their occurrence in foodstuffs from South China.

Concentrations, Profiles, and Health Risks of Organic Ultraviolet Filters in Eight Food Categories Determined through the Sixth Chinese Total Diet Study

Ultraviolet (UV) filters are emerging contaminants that have been found in high concentrations in human tissues. Food intake is generally considered to be the primary route of human exposure to contaminants. In this study, 184 composite food samples, prepared from 4268 individual samples in eight categories collected from 23 Chinese provinces for the sixth Chinese total diet study, were analyzed. The total and median UV filter concentrations in food samples were 1.5-68.3 and 7.9 ng/g wet weight, respectively. The highest median concentrations were found in decreasing order in meat, cereals, and legumes. In total, 15 UV filters were analyzed. 2-Ethylhexyl salicylate, homosalate, and 2-ethylhexyl-4-methoxycinnamate were dominant and made median contributions of 34.1%, 22.6%, and 14.5%, respectively, and 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol contributed the median of 0.03%, of the total UV filter concentrations. The estimated total daily UV filter intake in animal-origin foods and total UV filter concentration in human milk from the same province were significantly correlated (r = 0.44, p < 0.05). Predicted absorption, distribution, metabolism, and elimination properties led to 10 UV filters being prioritized as most likely to be retained in human tissues. The prioritization results and toxicity assessments indicated that octocrylene and 2-ethylhexyl-4-methoxycinnamate have stronger effects in vivo and therefore require more attention than others.

A modified QuEChERS method for determination of organophosphate esters in milk by GC-MS

Organophosphate esters (OPEs) are substances that have been detected in several matrices due to their use as flame retardants and plasticizers. Human exposure to OPEs can cause endocrine disruption, hormonal problems, and reproductive disturbance. Ingestion of contaminated food can be a significant route of exposure to OPEs. Food can be contaminated by OPEs in the food chain, during cultivation, and by contact with plasticizers during the production chain of processed foods. In this study, a method for the determination of 10 OPEs in commercial bovine milk was developed. The procedure was based on QuEChERS extraction and gas chromatography coupled to mass spectrometry (GC-MS) analysis. QuEChERS modification included a freezing-out step after the extraction followed by the concentration of the entire acetonitrile phase before the clean-up step. Calibration linearity, matrix effects, recovery, and precision were evaluated. Significant matrix effects were observed, which could be compensated by the isotopically labeled internal standard quantification and matrix-matched calibration curves. Recoveries ranged from 77 to 105%, with a relative standard deviation ranging from 3 to 38%. The method detection limits (MDLs) were in the range of 0.031-6.7 ng mL^-1, while the method quantification limits (MQLs) were within the range from 0.27 to 20 ng mL^-1. The proposed method was successfully validated and applied to determine the concentrations of OPEs in bovine milk. The 2-ethylhexyl diphenyl phosphate (EHDPHP) was detected in the analyzed milk samples but at levels below the MQL.

Occurrence and risk assessment of organophosphate esters in global aquatic products

Organophosphate esters (OPEs), as an important class of new pollutants, have been pervasively detected in global aquatic products, arousing widespread public concern due to their potential bioaccumulative behavior and consequent risks. With the continuous improvement of living standards of citizens, there have been constant increment of the proportion of aquatic products in diets of people. The levels of OPEs exposed to residents may also be rising due to the augmented consumption of aquatic products, posing potential hazards on human health, especially for people in coastal areas. The present study integrated the concentrations, profiles, bioaccumulation, and trophic transfer of OPEs in global aquatic products, including Mollusca, Crustacea, and fish, evaluated health risks of OPEs through aquatic products in daily diets by Mont Carol Simulation (MCS), and found Asia has been the most polluted area in terms of the concentration of OPEs in aquatic products, and would have been increasingly polluted. Among all studied OPEs, chlorinated OPEs generally showed accumulation predominance. It is worth noting that some OPEs were found bioaccumulated and/or biomagnified in aquatic ecosystems. Though MCS revealed relative low exposure risks of residents, sensitive and special groups such as children, adolescents, and fishermen may face more serious health risks than the average residents. Finally, knowledge gaps and recommendations for future research are discussed encouraging more long-term and systematic global monitoring, comprehensive studies of novel OPEs and OPEs metabolites, and more toxicological studies to completely evaluate the potential risks of OPEs.

Organophosphate Flame Retardants in Pregnant Women: Sources, Occurrence, and Potential Risks to Pregnancy Outcomes

Organophosphate flame retardants (OPFRs) are found in various environmental matrixes and human samples. Exposure to OPFRs during gestation may interfere with pregnancy, for example, inducing maternal oxidative stress and maternal hypertension during pregnancy, interfering maternal and fetal thyroid hormone secretion and fetal neurodevelopment, and causing fetal metabolic abnormalities. However, the consequences of OPFR exposure on pregnant women, impact on mother-to-child transmission of OPFRs, and harmful effects on fetal and pregnancy outcomes have not been evaluated. This review describes the exposure to OPFRs in pregnant women worldwide, based on metabolites of OPFRs (mOPs) in urine for prenatal exposure and OPFRs in breast milk for postnatal exposure. Predictors of maternal exposure to OPFRs and variability of mOPs in urine have been discussed. Mother-to-child transmission pathways of OPFRs have been scrutinized, considering the levels of OPFRs and their metabolites in amniotic fluid, placenta, deciduae, chorionic villi, and cord blood. The results showed that bis(1,3-dichloro-2-propyl) phosphate (BDCIPP) and diphenyl phosphate (DPHP) were the two predominant mOPs in urine, with detection frequencies of >90%. The estimated daily intake (EDI_M) indicates low risk when infants are exposed to OPFRs from breast milk. Furthermore, higher exposure levels of OPFRs in pregnant women may increase the risk of adverse pregnancy outcomes and influence the developmental behavior of infants. This review summarizes the knowledge gaps of OPFRs in pregnant women and highlights the crucial steps for assessing health risks in susceptible populations, such as pregnant women and fetuses.

Dietary Exposure and Health Risk of the Emerging Contaminant Fluorinated Liquid-Crystal Monomers

Fluorinated liquid-crystal monomers (FLCMs) widely used in liquid crystal displays are considered to be a new generation of persistent, bioaccumulative, and toxic contaminants. They have been widely detected in the environment. However, little is known about their occurrence in food and human dietary exposure until now. Herein, we provided an evaluation of dietary exposure and health risks of FLCMs in the Chinese adult population based on the fifth and sixth total diet studies (TDSs). The detection frequencies of FLCMs in the two surveys were 90.5 and 99.5%, with concentrations ranging from not detected ∼72.6 μg/kg wet weight (ww) and ND ∼74.7 μg/kg ww, respectively. All TDS samples contained the multiresidue of FLCMs. The mean estimated daily intakes (EDIs) of FLCMs were 172.86 and 163.10 ng/kg bw/day in the fifth and sixth TDS, respectively. Meats, vegetables, and cereals contributed the most to the EDI of FLCMs. According to the threshold of toxicological concern (TTC) method, the EDIs of 1-fluoro-4-[2-(4-propylphenyl)ethynyl]benzene (4.56 and 3.26 ng/kg bw/day) and 2-fluoro-4-[4'-propyl-1,1'-bi(cyclohexyl)-4-yl]phenyl trifluoromethyl ether (3.12 and 3.28 ng/kg bw/day) were above their TTC value (2.5 ng/kg bw/day), suggesting their potential health risk. This is the first comprehensive national dietary exposure assessment of FLCMs.

Organophosphate esters in Chinese rice: Occurrence, distribution, and human exposure risks

Dietary intake is a crucial pathway of organophosphate esters (OPEs) exposure for human. However, information about the exposure risk of OPEs via rice consumption is still largely unknown. In the present study, a total of 234 rice samples from 25 provinces or city of China were collected and the concentrations of 24 OPEs were determined. Sixteen OPEs were detected in these rice samples and each rice sample was contaminated with at least 5 OPEs, indicating a ubiquitous occurrence of OPEs in Chinese rice. Moreover, the concentrations of Σ16 OPEs ranged from 1.46 to 552.65 μg/kg dry weight (dw), with a mean value of 64.74 μg/kg dw. For the composition profile of OPEs, three Cl-OPEs, including tris(2-chloroethyl) phosphate (TCEP), tri(2-chloroisopropyl) phosphate (TCIPP) and tris(1,3-dichloro-2-propyl) phosphate (TDCIPP), accounted for the highest proportion of Σ16 OPEs. For the spatial distribution of OPEs, although obvious spatial variations were observed among the 25 provinces or city, no obvious variations were found among the six rice-cultivating regions of China. Additionally, estimated dietary intakes (EDI) values of the 16 OPEs for adults and children were 1105.24 and 1399.13 ng/kg bw/day, respectively, under the high intake scenario. The hazard indexes of the 10 OPEs were 0.108 and 0.137 for adults and children, respectively. The risk assessment results indicated that Chinese adults and children did not suffer significant adverse effects from OPEs via rice intake.

Determination of benzothiazoles, benzotriazoles and benzenesulfonamides in seafood using quick, easy, cheap, effective, rugged and safe extraction followed by gas chromatography - tandem mass spectrometry: Method development and risk assessment

The common use of benzothiazoles, benzotriazoles and benzenesulfonamides has led to widespread ubiquity in several environmental matrices. Their occurrence in edible fish could represent an additional exposure route for the population. The present study aims to develop a method for the simultaneous determination of these three compound families in seafood samples. Based on QuEChERS extraction, different salt combinations and clean-up strategies have been evaluated to achieve the highest recoveries while reducing the matrix effect in low and high lipidic content species. The best results were obtained with the original method salts and the lipid-selective push-through clean-up, which combined with gas chromatography-tandem mass spectrometry led to recoveries between 50 and 112% with negligible matrix effects and method detection limits between 0.15-9.50 ng g^-1 dw. The application of the method to commercially available samples confirmed the presence of BTs as well as BSAs, with the latter being determined in seafood for the first time. Exposure and risk assessment calculations indicated a minor risk for the population when consuming fish.

Legacy and novel brominated flame retardants in animal-derived foods from China Total Diet Study (CTDS): Temporal trends, evidence of substitution, and dietary exposure assessment

Based on the 6th China Total Diet Study (CTDS) conducted in 2016-2019, the occurrence of both legacy and novel brominated flame retardants (BFRs) was measured in animal-derived foods collected across China. Most BFRs could be frequently detected in food samples, indicating their ubiquity in the environment. Decabromodiphenyl ethane (DBDPE), a typical novel BFR, presented the highest contamination level, whereas legacy BFRs, including decabrominated diphenyl ether (BDE-209), tetrabromobisphenol A (TBBPA), and hexabromocyclododecane (HBCDD), still presented high detection frequencies and relatively abundant proportions in total BFRs. Compared with previous CTDSs conducted from 2007 to 2011, the levels and estimated dietary intakes (EDIs) of most BFRs showed a significant downtrend, which suggested that flame retardant consumption in China has transferred from legacy BFRs to novel BFRs (mainly DBDPE) and from BFRs to other kinds of flame retardants. Based on probabilistic estimation, the median EDIs of mainly used BFRs for the Chinese population ranged from 41.0 to 1.67 × 10³ pg/kg bw/day, and meat consumption was the primary source in dietary BFR intake. By conducting the margin of exposure (MOE) approach or comparing with the reference dose (RfD), it can be concluded that daily dietary intakes of BFRs were still unable to cause significant health risks to the general population in China.

A global survey of organophosphate esters and their metabolites in milk: Occurrence and dietary intake via milk consumption

The first global survey of organophosphate esters (OPEs) and their metabolites (mOPEs) in milk was carried out in this study. Concentrations of 21 OPEs and 9 mOPEs were measured in 178 milk samples collected from 30 countries located on 5 continents, and the ubiquity of both OPEs and mOPEs was observed in milk. Concentrations of ∑₂₁OPEs ranged from 53.3 pg/mL to 4270 pg/mL, with a median level of 367 pg/mL. The median level of ∑₉mOPEs was 153 pg/mL, with a range of 15-7440 pg/mL. No difference was observed among the levels of both ∑₂₁OPEs and ∑₉mOPEs in milk from the five continents. For the relationship between mOPEs and their parent OPEs, some pairs presented significant and positive correlations, which indicated that they shared similar sources. Estimated daily intakes (EDIs) of OPEs/mOPEs via milk consumption were calculated. Asian countries presented relatively low EDIs, and European and American countries, especially Denmark, the Netherlands, Finland and Argentina, presented high EDIs. Current daily OPE intake via milk consumption for global adult populations was far lower than the corresponding reference dose; however, considering that human intake of OPEs occurs via multiple sources, it is too early to conclude that the intake of OPEs were unable to cause health concerns.

Discovery of 18 Organophosphate Esters and 3 Organophosphite Antioxidants in Food Contact Materials Using Suspect and Nontarget Screening: Implications for Human Exposure

In this study of extracts of 100 food contact material (FCM) samples collected from South China, we identified 21 organophosphate esters (OPEs) by suspect screening and seven novel OPEs by characteristic fragments-based nontarget screening. Six organophosphite antioxidants (OPAs) were further identified using a suspect list derived from these identified OPEs. Of these compounds, 18 OPEs and 3 OPAs were found for the first time in the extracts of FCMs. (Semi-)quantification revealed that seven of the OPEs [triphenyl phosphate, tris(2,4-di-tert-butylphenyl) phosphate (TDtBPP), bis(2,4-di-tert-butylphenyl) methyl phosphate, (2,4-di-tert-butylphenyl)pentaerythritol phosphate, triethyl phosphate, 2-ethylhexyl-diphenyl phosphate, and trimethyl phosphate] and two of the OPAs [tris(2,4-di-tert-butylphenyl) phosphite (TDtBPPi) and pentabutylated triphenyl phosphite] were present in more than 50 FCM samples and that TDtBPP and TDtBPPi were the dominant OPE and OPA in FCMs, respectively [with median concentrations of 7260 ng/g (range: <8.50-103,879 ng/g) and 31,920 ng/g (range: <9.80-657,399 ng/g), respectively]. A migration test revealed that the migration efficiencies of compounds from a plastic coffee cup to food simulants in the cup increased as the ethanol/water ratio in the food simulants increased. This study significantly enhanced our understanding on the diversity and occurrences of OPEs and OPAs in FCMs used in China and their FCM-to-food migration risk.

Human dietary exposure to bisphenol-diglycidyl ethers in China: Comprehensive assessment through a total diet study

Despite the widespread use of bisphenol A diglycidyl ether (BADGE) and bisphenol F diglycidyl ether (BFDGE) in various consumer products as protective plasticizer, studies on human dietary exposure to these compounds are scare. In this study, nine bisphenol diglycidyl ethers (BDGEs) including BADGE, BFDGE, and seven of their derivatives were determined in the Chinese adult population based on composite dietary samples collected from the sixth (2016-2019) China total diet study (TDS). Contamination level of nine BDGEs was determined in 288 composite dietary samples from 24 provinces in China. BADGE·2H₂O and BADGE are the most frequently detected and BADGE·2H₂O presented the highest mean concentration (2.402 μg/kg). The most contaminated food composite is meats, with a mean ∑₉BDGEs of 8.203 μg/kg, followed by aquatic products (4.255 μg/kg), eggs (4.045 μg/kg), and dairy products (3.256 μg/kg). The estimated daily intake (EDI) of ∑₉BDGEs based on the mean and 95th percentile concentrations are 121.27 ng/kg bw/day and 249.71 ng/kg bw/day. Meats, eggs, and aquatic products are the main source of dietary exposure. Notably, beverages and water, alcohols were the main contributors of dietary exposure to BADGE and BADGE·2H₂O, followed by animal-derived foods. Dietary exposure assessment demonstrated that human dietary BDGEs do not pose risks to general population based on the mean and 95th percentile hazard index with < 1. This is the first comprehensive national dietary exposure assessment of BDGEs in Chinese general population.

Organophosphate esters in UK diet; exposure and risk assessment

Food ingestion has been established as an important human exposure route to many environmental contaminants (brominated flame retardants, dioxins, organochlorine pesticides etc). However, information regarding dietary exposure to organophosphate esters (OPEs) in the UK remains limited. This study provides the first comprehensive dataset on OPEs in the UK diet by measuring concentrations of eight OPEs in 393 food samples, divided into 15 food groups, collected from Birmingham, UK. All target OPEs were measured above the limit of quantification in at least one of the food groups analysed. Concentrations were highest (mean ∑₈OPEs = 18.4 ng/g wet weight (ww)) in milk and milk products, followed by those in cereal and cereal products (mean ∑₈OPEs = 15.9 ng/g ww), with concentrations lowest in chickens' eggs (mean ∑₈OPEs = 1.61 ng/g ww). Interestingly, concentrations in animal-derived foods (mean ∑₈OPEs = 44.2 ng/g ww) were statistically indistinguishable (p˃0.05) from plant-derived foods (mean ∑₈OPEs = 36.8 ng/g ww). Estimated daily dietary intakes (EDIs) of ∑₈OPEs under mean and high-end exposure scenarios for the four age groups considered were: toddlers (420 and 1547 ng/kg bw/day) ˃ children (155 and 836) ˃ elderly (74.3 and 377) ˃ adults (62.3 and 278) ng/kg bw/day, respectively. Baby food contributed 39 % of ∑₈OPEs exposure for toddlers, with non-alcoholic beverages contributing 27 % of exposure for children, while cereal and cereal products (25 %) and fruits (22 %) were the main contributors for adults and the elderly. The concentrations of OPEs in UK foodstuffs were generally of the same order of magnitude as those reported for other countries and our estimates of dietary exposure were well below the corresponding health-based limit values.

Organophosphate Esters in Foodstuffs from Multiple Provinces in China: Possible Sources during Food Processing and Implications for Human Exposure

With increasing application of organophosphate esters (OPEs) as flame retardants and plasticizers in the world, the health and ecological risks posed by these chemicals have raised people's concern over the years. Despite the fact that dietary intake is an important pathway for human exposure to OPEs, monitoring on OPEs in foodstuffs is scarce. In this study, we measured 14 OPEs in both packaged (n = 229) and fresh (n = 58) foodstuffs collected across China with a new method that was developed by two-stage solid-phase extraction. The total concentrations of OPEs (ΣOPEs) in 12 categories of packaged foodstuffs and 5 categories of fresh foodstuffs were in the range of 0.212-273 ng/g wet weight (ww) [geometric mean (GM): 5.06 ng/g ww] and 0.189-2.82 ng/g ww (GM: 0.618 ng/g ww), respectively. Significantly higher levels of ΣOPEs were found in packaged food categories of fruits and meat than those in the corresponding fresh ones, implying the extra introduction of OPEs during the processing and storage of foodstuffs. Correlation analysis showed that the GM concentrations of individual OPEs in animal-derived foods with few industrial processing were positively correlated with their annual production volumes in China in 2020, emphasizing the significance of natural sources of OPEs in these food samples. Elevated levels of ΣOPEs (range: 8.94-4120 and GM: 274 ng/g) were found in food-packaging materials, and the predominant OPE analogues were consistent with those found in packaged food samples. The result implies that the food-packaging material can be an important contamination source of OPEs in packaged foodstuffs, which is in particular true for triphenyl phosphate, tris(2-chloroisopropyl) phosphate, tris(2-chloroethyl) phosphate, and 2-ethylhexyl diphenyl phosphate. The median daily intake of ΣOPEs via food was estimated as 65.4 ng/kg bw/day for adults in China, and the category of cereals was the major contributor (72.7%) of the dietary exposure to OPEs. The exposure risk of OPEs via food intake was generally low for the Chinese population. Overall, this study establishes a baseline concentration for OPEs in Chinese foodstuffs and uncovers food contact material as a potential source of OPEs in foods. It is expected that the research in terms of food safety and OPE contamination will benefit from this work.

Organophosphate esters and their diester metabolites in infant formulas and baby supplementary foods collected in Beijing, China: Occurrence and the implications for infant exposure

Organophosphate esters (OPEs) have been extensively used as flame retardants and/or plasticizers and they found to be ubiquitous in various environmental matrices along with the gradual phase-out of brominated flame retardants (BFRs). Moreover, their main metabolites, organophosphate di-esters (di-OPEs), were also frequently detected. However, few studies focused on the occurrence of OPEs and di-OPEs in foods. In this study, fourteen OPEs and five di-OPEs were measured in infant formula and baby supplementary food (BSF) collected in Beijing, China. Most OPEs and di-OPEs presented high detection frequencies, which indicated their ubiquity in baby foods. The concentrations of ∑₁₄OPEs in the 75 infant formula samples ranged from 0.79 to 159 ng/g, with a median of 23.2 ng/g, and in which triphenyl phosphate (TPhP) was the most abundant compound. The concentrations of ∑₁₄OPEs in the 32 BSF samples were 4.42-115 ng/g (median: 19.5 ng/g), and tri(3-chloropropyl) phosphate (TCIPP) was predominant. Moreover, no significant difference was observed between OPE levels in infant formula and BSF. The median concentrations of Σ₅di-OPEs in infant formula and BSF were 3.39 and 5.43 ng/g, respectively. However, no significantly correlation was observed between concentrations of di-OPEs and their parent compounds, which indicated they have different sources. The median estimated dietary intakes (EDIs) of the ∑₁₄OPEs were from 165 to 383 ng/kg bodyweight (bw)/day for infants via infant formula feeding, and were from 429 to 470 ng/kg bw/day via BSF feeding. A comparison to corresponding reference dose (RfD) suggested that dietary intakes of OPEs to Beijing infants via formula/BSF consumption were still unable to cause significant health concerns. However, EDIs of OPEs for infants were found to be significantly higher than that for Chinese adults, and dietary intake might be the predominant OPE intake pathway for infants. To our knowledge, this is the first study to investigate OPEs and their metabolites in baby foods.