Organophosphite Antioxidants and Novel Organophosphate Esters in Dust from China: Large-Scale Distribution and Heterogeneous Phototransformation

Contamination of dairy products with tris(2,4-di-tert-butylphenyl) phosphite and implications for human exposure

Tris(2,4-di-tert-butylphenyl) phosphite (AO168), an organophosphite antioxidant, can be oxidized to tris(2,4-di-tert-butylphenyl) phosphate (AO168 = O) during the production, processing, and application of plastics. AO168 = O can be further transformed to bis(2,4-di-tert-butylphenyl) phosphate and 2,4-di-tert-butylphenol. Here, we discovered the contamination of AO168 and its transformation products in dairy products for the first time. More samples contained AO168 (mean concentration: 8.78 ng/g wet weight [ww]), bis(2,4-di-tert-butylphenyl) phosphate (mean:11.1 ng/g ww) and 2,4-di-tert-butylphenol (mean: 46.8 ng/g ww) than AO168 = O (mean: 40.2 ng/g ww). The concentrations of AO168 and its transformation products were significantly correlated, and differed with the packaging material and storage conditions of the product. Estimated daily intakes (EDIs) of AO168 and its transformation products were calculated. Although the overall dietary risks were below one, transformation products accounted for 96.7% of the total hazard quotients. The high-exposure EDIs of total AO168 were above the threshold of toxicological concern (300 ng/kg bw/day), and deserve continual monitoring.

Traditional and Novel Organophosphate Esters in Plastic Greenhouse: Occurrence, Multimedia Migration, and Exposure Risk via Vegetable Consumption

The migration and risk of organophosphate esters (OPEs) in agricultural air-soil-plant multimedia systems due to plastic film application remain unclear. This study investigates the multimedia distribution of traditional OPEs (TOPEs), novel OPEs (NOPEs), and their transformation products (POPEs) in plastic and solar greenhouses. The total concentration of OPE-associated contaminants in air and airborne particles ranged from 594 to 1560 pg/m3 and 443 to 15600 ng/g, respectively. Significant correlations between air OPE concentrations and those in polyolefin film (P < 0.01) indicate plastic film as the primary source. Contaminants were also found in soils (96.8-9630 ng/g) and vegetables (197-7540 ng/g). The primary migration pathway for NOPEs was particle dry deposition onto the soil and leaf, followed by plant accumulation. Leaf absorption was the main uptake pathway for TOPEs and POPEs, influenced by vegetable specific leaf surface area. Moreover, total exposure to OPE-associated contaminants via vegetable intake was assessed at 2250 ng/kg bw/day for adults and 2900 ng/kg bw/day for children, with an acceptable hazard index. However, a high ecological risk was identified for NOPE compounds (median risk quotient, 975). This study provides the first evidence of the multimedia distribution and potential threat posed by OPE-associated contaminants in agricultural greenhouses.

A new approach to monitoring typical organophosphorus compounds (OPs) in environmental media: From database building to suspect screening

Organophosphorus compounds (OPs) are widely used as flame retardants (FRs) and plasticizers, yet strategies for comprehensively screening of suspect OPs in environmental samples are still lacking. In this work, a neoteric, robust, and general suspect screening technique was developed to identify novel chemical exposures by use of ultra-high performance liquid chromatography-Q Exactive hybrid quadrupole-Orbitrap high resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS). We firstly established a suspect chemical database which had 7,922 OPs with 4,686 molecular formulas, and then conducted suspect screening in n = 50 indoor dust samples, n = 76 sediment samples, and n = 111 water samples. By use of scoring criteria such as retention time prediction models, we successfully confirmed five compounds by comparison with their authentic standards, and prioritized three OPs candidates including a nitrogen/fluorine-containing compound, that is dimethyl {1H-indol-3-yl[3-(trifluoromethyl)anilino]methyl} phosphonate (DMITFMAMP). Given that the biodegradation half-life values in water (t1/2,w) of DMITFMAMP calculated by EPI Suite is 180 d, it is considered to be potentially persistent. This strategy shows promising potential in environmental pollution assessment, and can be expected to be widely used in future research.

Contamination Status of Novel Organophosphate Esters Derived from Organophosphite Antioxidants in Soil and the Effects on Soil Bacterial Communities

The contamination status of novel organophosphate esters (NOPEs) and their precursors organophosphite antioxidants (OPAs) and hydroxylated/diester transformation products (OH-OPEs/di-OPEs) in soils across a large-scale area in China were investigated. The total concentrations of the three test NOPEs in soil were 82.4-716 ng g-1, which were considerably higher than those of traditional OPEs (4.50-430 ng g-1), OPAs (n.d.-30.8 ng g-1), OH-OPEs (n.d.-0.49 ng g-1), and di-OPEs (0.57-21.1 ng g-1). One NOPE compound, i.e., tris(2,4-di-tert-butylphenyl) phosphate (AO168 = O) contributed over 65% of the concentrations of the studied OPE-associated contaminants. A 30-day soil incubation experiment was performed to confirm the influence of AO168 = O on soil bacterial communities. Specific genera belonging to Proteobacteria, such as Lysobacter and Ensifer, were enriched in AO168 = O-contaminated soils. Moreover, the ecological function of methylotrophy was observed to be significantly enhanced (t-test, p < 0.01) in soil treated with AO168 = O, while nitrogen fixation was significantly inhibited (t-test, p < 0.01). These findings comprehensively revealed the contamination status of OPE-associated contaminants in the soil environment and provided the first evidence of the effects of NOPEs on soil microbial communities.

Acute exposure to tris(2,4-di-tert-butylphenyl)phosphate elicits cardiotoxicity in zebrafish (Danio rerio) larvae via inducing ferroptosis

Tris(2,4-di-tert-butylphenyl)phosphate (AO168 =O), a novel organophosphate ester, is prevalent and abundant in the environment, posing great exposure risks to ecological and public health. Nevertheless, the toxicological effects of AO168 =O remain entirely unknown to date. The results in this study indicated that acute exposure to AO168 =O at 10 and 100 μg/L for 5 days obviously impaired cardiac morphology and function of zebrafish larvae, as proofed by decreased heartbeat, stroke volume, and cardiac output and the occurrence of pericardial edema and ventricular hypertrophy. Transcriptomics, polymerase chain reaction, and molecular docking revealed that the strong interaction of AO168 =O and transferrin receptor 1 activated the transportation of ferric iron into intracellular environment. The release of free ferrous ion to cytoplasmic iron pool also contributed to the iron overload in heart region, thus inducing ferroptosis in larvae via generation of excessive reactive oxygen species, glutathione peroxidase 4 inhibition, glutathione depletion and lipid peroxidation. Ferroptosis inhibitor (Fer-1) co-exposure effectively relieved the cardiac dysfunctions of zebrafish, verifying the dominant role of ferroptosis in the cardiotoxicity caused by AO168 =O. This research firstly reported the adverse impact and associated mechanisms of AO168 =O in cardiomyogenesis of vertebrates, underlining the urgency of concerning the health risks of AO168 =O.

Uptake, translocation, and metabolism of organophosphate esters (OPEs) in plants and health perspective for human: A review

Plant uptake, accumulation, and transformation of organophosphate esters (OPEs) play vital roles in their geochemical cycles and exposure risks. Here we reviewed the recent research advances in OPEs in plants. The mean OPE concentrations based on dry/wet/lipid weight varied in 4.80-3,620/0.287-26.8/12,000-315,000 ng g-1 in field plants, and generally showed positive correlations with those in plant habitats. OPEs with short-chain substituents and high hydrophilicity, particularly the commonly used chlorinated OPEs, showed dominance in most plant samples, whereas some tree barks, fruits, seeds, and roots demonstrated dominance of hydrophobic OPEs. Both hydrophilic and hydrophobic OPEs can enter plants via root and foliar uptake, and the former pathway is mainly passively mediated by various membrane proteins. After entry, different OPEs undergo diverse subcellular distributions and acropetal/basipetal/intergenerational translocations, depending on their physicochemical properties. Hydrophilic OPEs mainly exist in cell sap and show strong transferability, hydrophobic OPEs demonstrate dominant distributions in cell wall and limited migrations owing to the interception of Casparian strips and cell wall. Additionally, plant species, transpiration capacity, growth stages, commensal microorganisms, and habitats also affect OPE uptake and transfer in plants. OPE metabolites derived from various Phase I transformations and Phase II conjugations are increasingly identified in plants, and hydrolysis and hydroxylation are the most common metabolic processes. The metabolisms and products of OPEs are closely associated with their structures and degradation resistance and plant species. In contrast, plant-derived food consumption contributes considerably to the total dietary intakes of OPEs by human, particularly the cereals, and merits specifical attention. Based on the current research limitations, we proposed the research perspectives regarding OPEs in plants, with the emphases on their behavior and fate in field plants, interactions with plant-related microorganisms, multiple uptake pathways and mechanisms, and comprehensive screening analysis and risk evaluation.

Nontarget Identification of Novel Organophosphorus Flame Retardants and Plasticizers in Indoor Air and Dust from Multiple Microenvironments in China

The indoor environment is a typical source for organophosphorus flame retardants and plasticizers (OPFRs), yet the source characteristics of OPFRs in different microenvironments remain less clear. This study collected 109 indoor air samples and 34 paired indoor dust samples from 4 typical microenvironments within a university in Tianjin, China, including the dormitory, office, library, and information center. 29 target OPFRs were analyzed, and novel organophosphorus compounds (NOPs) were identified by fragment-based nontarget analysis. Target OPFRs exhibited the highest air and dust concentrations of 46.2-234 ng/m3 and 20.4-76.0 μg/g, respectively, in the information center, where chlorinated OPFRs were dominant. Triphenyl phosphate (TPHP) was the primary OPFR in office air, while tris(2-chloroethyl) phosphate dominated in the dust. TPHP was predominant in the library. Triethyl phosphate (TEP) was ubiquitous in the dormitory, and tris(2-butoxyethyl) phosphate was particularly high in the dust. 9 of 25 NOPs were identified for the first time, mainly from the information center and office, such as bis(chloropropyl) 2,3-dichloropropyl phosphate. Diphenyl phosphinic acid, two hydroxylated and methylated metabolites of tris(2,4-ditert-butylphenyl) phosphite (AO168), and a dimer phosphate were newly reported in the indoor environment. NOPs were widely associated with target OPFRs, and their human exposure risk and environmental behaviors warrant further study.

Occurrence, potential sources, and ecological risks of traditional and novel organophosphate esters in facility agriculture soils: A case study in Beijing, China

Although traditional organophosphate esters (OPEs) in soils have attracted widespread interest, there is little information on novel OPEs (NOPEs), especially in facility agriculture soils. In this work, we surveyed 11 traditional OPEs, four NOPEs, and four corresponding organophosphite antioxidant precursors (OPAs) for the NOPEs in soil samples collected from facility greenhouses and open fields. The median summed concentrations of traditional OPEs and NOPEs were 14.1 μg/kg (range: 5.38-115 μg/kg) and 702 μg/kg (range: 348-1952 μg/kg), respectively, in film-mulched soils from greenhouses. These concentrations were much higher than those in soils without mulch films, which suggests that OPEs in soils are associated with plastic mulch films. Tris(2,4-di-tert-butylphenyl) phosphate, which is a NOPE produced by oxidation of (2,4-di-tert-butylphenyl) phosphite, was the predominant congener in farmland soils, with concentrations several orders of magnitude greater than those of traditional OPEs. Comparisons of OPEs in different mulch films and the corresponding mulched soils revealed that degradable and black films caused more severe pollution than polyethylene and white films. Traditional OPEs, including tris(2-ethylhexyl) phosphate and tricresyl phosphate, exhibited moderate risks in farmland soils, especially in film-mulched soils. NOPEs, including trisnonylphenol phosphate, posed high ecological risks to the terrestrial ecosystem. Risk evaluations should be conducted for a broad range of NOPEs in the environment.

Discovering Novel Organophosphorus Compounds in Wastewater Treatment Plant Effluents through Suspect Screening and Nontarget Analysis

Limited knowledge on the structure of emerging organophosphorus compounds (OPCs) hampers our comprehensive understanding of their environmental occurrence and potential risks. Through suspect and nontarget screening, combining data-dependent acquisition, data-independent acquisition, and parallel reaction monitoring modes, we identified 60 OPCs (17 traditional and 43 emerging compounds) in effluents of 14 wastewater treatment plants (WWTPs) in Beijing and Qinghai, China. These OPCs comprise 26 organophosphate triesters, 17 organophosphate diesters, 6 organophosphonates, 7 organothiophosphate esters, and 4 other OPCs. Notably, 14 suspect OPCs were newly identified in WWTP effluents, and 16 nontarget OPCs were newly discovered in environmental matrices. Specifically, the cyclic phosphonate, (5-ethyl-2-methyl-1,3,2-dioxaphosphorinan-5-yl)methyl dimethyl phosphonate P-oxide (PMMMPn), consistently appeared in all WWTP effluents, with semiquantitative concentrations ranging from 44.4 to 282 ng/L. Its analogue, di-PMMMPn, presented in 93% of wastewater samples. Compositional differences between the WWTP effluents of two cities were mainly attributed to emerging OPCs. Hazard and ecological risk assessment underscored the substantial contribution of chlorinated organophosphate esters and organothiophosphate esters to overall risks of OPCs in WWTP effluents. This study provides the most comprehensive OPC profiles in WWTP effluents to date, highlighting the need for further research on their occurrence, fate, and risks, particularly for chlorinated OPCs.

The hidden diet: Synthetic antioxidants in packaged food and their impact on human exposure and health

Synthetic antioxidants (AOs) are commonly used in everyday items and industrial products to inhibit oxidative deterioration. However, the presence of AOs in food packaging and packaged foods has not been thoroughly documented. Moreover, studies on human exposure to AOs through skin contact with packaging or ingesting packaged foods are limited. In this study, we analyzed twenty-three AOs-including synthetic phenolic antioxidants (SPAs) and organophosphite antioxidants (OPAs)-along with six transformation products in various food samples and their packaging materials. We found AOs in food products at concentrations ranging from 1.30 × 103 to 1.77 × 105 ng/g, which exceeded the levels in both outer packaging (6.05 × 102-3.07 × 104 ng/g) and inner packaging (2.27 × 102-1.09 × 105 ng/g). The most common AOs detected in foodstuffs were tris(2,4-di-tert-butylphenyl) phosphate (AO168O), butylated hydroxytoluene (BHT), and octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (AO1076), together constituting 95.7 % of the total AOs found. Our preliminary exposure assessment revealed that dietary exposure-estimated at a median of 2.55 × 104 ng/kg body weight/day for children and 1.24 × 104 ng/kg body weight/day for adults-is a more significant exposure route than dermal contact with packaging. Notably, four AOs were identified in food for the first time, with BHT making up 76.8 % and 67.6 % of the total BHT intake for children and adults, respectively. These findings suggest that food consumption is a significant source of BHT exposure. The estimated daily intakes of AOs via consumption of foodstuffs were compared with the recommended acceptable daily intake to assess the risks. This systematic investigation into AOs contributes to understanding potential exposure and health risks associated with AOs in packaged foods. It emphasizes the need for further evaluation of human exposure to these substances.

OPEs-ID: A software for non-targeted screening of organophosphate esters based on liquid chromatography-high-resolution mass spectrometry

Organophosphate esters (OPEs) are widely used as flame retardants and plasticizers, presenting a potential threat to the environment and human health. To date, no automatic software exists for the nontargeted screening of OPEs. In this study, OPEs-ID, a user-friendly software, was developed for the identification of OPEs using liquid chromatography-high-resolution mass spectrometry. The main workflow of OPEs-ID included fragments-dependent precursor ion screening, elemental composition determination, extracted ion chromatograms (EIC) comparison, and molecular structure identification via MetFrag strategy. A mixture of 17 OPE standards was identified with an identification rate of 100% by OPEs-ID. OPEs-ID demonstrated a rate of 94.1% for correctly ranking within the top 1 candidate in a local database (41.2% in PubChem) for the 17 OPE standards, which remarkably improved the identification when compared to conventional in silico fragmentation algorithms. Using a pooled airborne fine particle sample (PM2.5), OPEs-ID could automatically retrieve 22 valid molecules with structure candidates. The detection frequencies of 9 newly identified OPEs were between 13% and 100% in the 32 PM2.5 samples. Their semi-quantification concentrations were comparable to those of some traditional OPEs. Overall, OPEs-ID offers a powerful tool to significantly enrich our understanding of the OPEs present in the environment.

Heterogeneous Photodegradation Behavior of Liquid Crystal Monomers in Dust: Quantitative Structure-Activity Relationship and Product Identification

The heterogeneous photodegradation behavior of liquid crystal monomers (LCMs) in standard dust (standard reference material, SRM 2583) and environmental dust was investigated. The measured photodegradation ratios for 23 LCMs in SRM and environmental dust in 12 h were 11.1 ± 1.8 to 23.2 ± 1.1% and 8.7 ± 0.5 to 24.0 ± 2.8%, respectively. The degradation behavior of different LCM compounds varied depending on their structural properties. A quantitative structure-activity relationship model for predicting the degradation ratio of LCMs in SRM dust was established, which revealed that the molecular descriptors related to molecular polarizability, electronegativity, and molecular mass were closely associated with LCMs' photodegradation. The photodegradation products of the LCM compound 4'-propoxy-4-biphenylcarbonitrile (PBIPHCN) in dust, including •OH oxidation, C-O bond cleavage, and ring-opening products, were identified by nontarget analysis, and the corresponding degradation pathways were suggested. Some of the identified products, such as 4'-hydroxyethoxy-4-biphenylcarbonitrile, showed predicted toxicity (with an oral rat lethal dose of 50%) comparable to that of PBIPHCN. The half-lives of the studied LCMs in SRM dust were estimated at 32.2-82.5 h by fitting an exponential decay curve to the observed photodegradation data. The photodegradation mechanisms of LCMs in dust were revealed for the first time, enhancing the understanding of LCMs' environmental behavior and risks.

Bringing the emerging organophosphate flame retardants (eOPFRs) into view: A hidden ecological and human health threat

The production and usage of organophosphate flame retardants (OPFRs) in textiles, plastics, and electronics have surged, with phosphorus-based flame retardants constituting over 30 % of the global consumption of flame retardants. Meanwhile, concerns regarding the potential hazards of OPFRs to ecosystems and human health including disruptions in the endocrine system, inhibition of reproduction, and manifestation of developmental defects have intensified. However, our comprehensive data analysis has unveiled a pronounced and critical knowledge gap, as at present, a majority of studies emphasize the attributes of traditional OPFRs, such as triphenyl phosphate (TPHP), while emerging OPFRs (eOPFRs) remain undeservedly overlooked. We elaborated on the current advancements and challenges regarding eOPFRs research and demonstrated that eOPFRs exhibit considerable diversity in terms of their chemical structures, substantial residue levels, broad sources of occurrence, and limited understanding of their potent (eco)toxicological implications. In light of these attributes, it becomes evident that the environmental and health risks of eOPFRs can be comparable to, if not surpass, those attributed to traditional OPFRs. This compelling observation underscores an imperative need for heightened research focus and extensive research efforts dedicated to the study of eOPFRs, rather than still focusing on the realm of their traditional counterparts. Despite the challenges ahead, the emphasized environmental surveillance and toxicological assessment are imperative to prevent the potential evolution of these compounds into a significant ecological and human health threat.

Synthetic Antioxidants as Contaminants of Emerging Concern in Indoor Environments: Knowns and Unknowns

Synthetic antioxidants, including synthetic phenolic antioxidants (SPAs), amine antioxidants (AAs), and organophosphite antioxidants (OPAs), are essential additives for preventing oxidative aging in various industrial and consumer products. Increasing attention has been paid to the environmental contamination caused by these chemicals, but our understanding of synthetic antioxidants is generally limited compared to other emerging contaminants such as plasticizers and flame retardants. Many people spend a significant portion (normally greater than 80%) of their time indoors, meaning that they experience widespread and persistent exposure to indoor contaminants. Thus, this Perspective focuses on the problem of synthetic antioxidants as indoor environmental contaminants. The wide application of antioxidants in commercial products and their demonstrated toxicity make them an important family of indoor contaminants of emerging concern. However, significant knowledge gaps still need to be bridged: novel synthetic antioxidants and their related transformation products need to be identified in indoor environments, different dust sampling strategies should be employed to evaluate human exposure to these contaminants, geographic scope and sampling scope of research on indoor contamination should be broadened, and the partition coefficients of synthetic antioxidants among different media need to be investigated.

Indirect Emissions from Organophosphite Antioxidants Result in Significant Organophosphate Ester Contamination in China

Organophosphite antioxidants (OPAs) have been seriously neglected as potential sources of organophosphate esters (OPEs) in environments. This study utilizes a modeling approach to quantify for the first time national emissions and multimedia distributions of triphenyl phosphate (TPHP)─a well-known flame retardant─and three novel OPEs: tris(2,4-ditert-butylphenyl) phosphate (AO168═O), bis(2,4-ditert-butylphenyl) pentaerythritol diphosphate (AO626═O2), and trisnonylphenol phosphate (TNPP). Emphasis is on the quantitative assessment of OPA source in China. TPHP has 1.1-9.7 times higher emission (300 Mg/year in 2019 with half from OPA sources) than AO168═O (278 Mg/year), AO626═O2 (53 Mg/year), and TNPP (32 Mg/year), but AO168═O is predominant in environments (63-79%) except freshwaters. About 72-99% of the studied OPEs are emitted via air, with 88-99% ultimately distributed into soils as the major sink. OPA-source emissions contribute 9.5-57% and 4.7-56% of TPHP masses and concentrations (except in sediments) in different media, respectively. Both AO168═O and AO626═O2 exhibit high overall persistence ranging between 2 and 11 years. Source emissions and environmental concentrations are elevated in economically developed areas, while persistence is higher in northern areas, where precipitation and temperature are lower. This study shows the significance of the sources of OPA to OPE contamination, which supports chemical management of these substances.

Organophosphate esters (OPEs) in a heavily polluted river in South China: Occurrence, spatiotemporal trends, sources, and phase distribution

In the past decade, organophosphate esters (OPEs) undergo rapid increase in production and use. Meanwhile, owing to their additive property, OPEs exhibit liability to escape from related products and therefore ubiquity in various environments. Moreover, numerous researches verify their bioavailability and negative effects on biota and human, hence their occurrence and associated risks have caught much concern, particularly those in aquatic systems. So far, however, OPEs in water are generally investigated as a whole, their phase distribution and behavior in waterbodies are incompletely characterized. We examined 25 OPEs in water (including dissolved and particulate phases), sediment, and sediment core samples from the Lian River, which flows through the Guiyu e-waste recycling zone and Shantou specific economic zone in South China. Compared to most global waterbodies, the Lian River showed high or ultrahigh OPE levels in both water and sediments, particularly in the reaches surrounded by e-waste recycling and plastic-related industries, which were the top two greatest OPE sources. Non-industrial and agriculture-related anthropogenic activities also contributed OPEs. Sediment core data suggested that OPEs have been present in waters in Guiyu since the 1960s and showed a temporal trend consistent with the local waste-recycling business. The phase distribution of OPEs in the Lian River was significantly correlated with their hydrophobicity and solubility. Owing to their wide range of physicochemical properties, OPE congeners showed significant percentage differences in the Lian River water and sediments. Generally, OPEs in water reflect their dynamic real-time inputs, while those in sediment signify their accumulative deposition, which is another cause of their phase distribution disparities in the Lian River. The physicochemical parameters of OPEs first imposed negative and then positive influences on their dissolved phase-sediment distribution, indicating the involvement of both the adsorption of dissolved OPEs and the deposition of particle-bound OPEs.

Nontarget Identification of Novel Organophosphorus Flame Retardants and Plasticizers in Rainfall Runoffs and Agricultural Soils around a Plastic Recycling Industrial Park

Plastic recycling and reprocessing activities may release organophosphate ester (OPE) flame retardants and plasticizers into the surrounding environment. However, the relevant contamination profiles and impacts remain not well studied. This study investigated the occurrence of 28 OPEs and their metabolites (mOPEs) in rainfall runoffs and agricultural soils around one of the largest plastic recycling industrial parks in North China and identified novel organophosphorus compounds (NOPs) using high-resolution mass spectrometry-based nontarget analysis. Twenty and twenty-seven OPEs were detected in runoff water and soil samples, with total concentrations of 86.0-2491 ng/L and 2.53-199 ng/g dw, respectively. Thirteen NOPs were identified, of which eight were reported in the environment for the first time, including a chlorine-containing OPE, an organophosphorus heterocycle, a phosphite, three novel OPE metabolites, and two oligomers. Triphenylphosphine oxide and diphenylphosphinic acid occurred ubiquitously in runoffs and soils, with concentrations up to 390 ng/L and 40.2 ng/g dw, respectively. The downwind areas of the industrial park showed elevated levels of OPEs and NOPs. The contribution of hydroxylated mOPEs was higher in soils than in runoffs. These findings suggest that plastic recycling and reprocessing activities are significant sources of OPEs and NOPs and that biotransformation may further increase the ecological and human exposure risk.

Occurrence and Release of Organophosphite Antioxidants and Novel Organophosphate Esters from Plastic Food Packaging

Organic phosphite antioxidants (OPAs) are widely added in plastic products and can be oxidized to generate oxidized derivatives (OPAs = O), namely organic phosphate esters (OPEs), during production and use processing. Herein, the occurrence of OPEs and OPAs in five plastic food packages was detected by liquid chromatography-tandem mass spectrometry. Three OPEs (TPhP, TCEP, and AO168 = O) and three OPAs (TPhPi, TCEPi, and AO168) were found in the plastic packages, with concentrations of <MQL-124 ng/g (∑₃OPAs) and 196-831 ng/g (∑₃OPEs), respectively. The migration potential of OPAs and OPEs to food was measured by simulation experiments. OPAs and OPEs in plastic can efficiently migrate to oily simulants, alkaline simulants, and acidic simulants. After 14 days, the total concentration of all OPAs and OPEs in the food simulants reached <MQL-1.21 (acidic food simulants), <MQL-0.32 (alkaline food simulants), and 11.4-31.4 ng/mL (oily food simulants), respectively. OPAs and OPEs in 12 kinds of plastic-packaged foods were detected, with high concentrations in dairy food (∑₃OPAs + ∑₃OPEs: 18.3-28.9 ng/mL) and in oils (∑₃OPAs + ∑₃OPEs: 32.7-60.9 ng/mL). Accordingly, the estimated ingestion of OPAs and OPEs through plastic-packaged food can reach 2.6 and 32.7 ng/kg in children and 1.1 and 6.5 ng/kg in adults, indicating a non-negligible exposure risk of organic phosphorus pollutants.