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.

A comprehensive assessment of external exposure to persistent halogenated organic pollutants for residents in an e-waste recycling site, South China

Human skin wipes from 30 participants, air, dust, and food items were collected from a former electronic waste site in South China to provide a comprehensive understanding of residents' exposure to halogenated flame retardants (HFRs) and polychlorinated biphenyls (PCBs). The total concentration of halogenated organic pollutants (HOPs) in the dust, air, food and skin wipes ranged 240-25000 ng/g, 130-2500 pg/m3, 0.08-590 ng/g wet weight, and 69-28000 ng/m2, respectively. Wild fish, vegetables, and air were dominated by PCBs, whereas dust, livestock, and poultry were dominated by HFRs. The HOP concentrations were several orders of magnitude higher in local foodstuffs than in market foodstuffs. The chemical composition on the forehead was remarkably different from that on the hand. The importance of different exposure routes depends on the residents' food choices, except decabromodiphenyl ethane (DBDPE). For residents who consumed a 100-foot diet (mainly egg) and local wild fish, diet ingestion overwhelmed other exposure routes, and PCBs were mainly contributed by fish and HFRs by egg. For residents who consumed market food, the dermal absorption of most PCB congeners and dust ingestion of highly brominated flame retardants were relatively prominent. Inhalation was found to be a crucial route for pentabromoethylbenzene (PBEB).

Multi-pathway exposure assessment of organophosphate flame retardants in a southern Chinese population: Main route identification with compound-specificity

In this study, we conducted comprehensive organophosphorus flame retardant (PFR) exposure assessments of both dietary and non-dietary pathways in a rural population in southern China. Skin wipes were collected from 30 volunteers. Indoor and outdoor air (gas and particles), dust in the houses of these volunteers, and foodstuffs consumed by these volunteers were simultaneously collected. The total PFR concentrations in dust, gas, and PM2.5 varied from 53.8 to 5.14 × 105 ng/g, 0.528 to 4.27 ng/m3, and 0.390 to 16.5 ng/m3, respectively. The forehead (median of 1.36 × 103 ng/m2) and hand (median of 920 ng/m2) exhibited relatively high PFR concentrations, followed by the forearm (median of 440 ng/m2) and upper arm (median of 230 ng/m2). The PFR concentrations in the food samples varied from 0.0700 to 10.9 ng/g wet weight in the order of egg > roast duck/goose and vegetable > pork > chicken > fish. Tris(1-chloro-isopropyl) phosphate (TCPP) was the main PFR in the non-diet samples, whereas the profiles of PFR individuals varied by food type. Among the multiple pathways investigated (inhalation, dermal exposure, dust ingestion, and food ingestion), dermal absorption and dust ingestion were the predominant pathways for tris(2-chloroethyl) phosphate (TCEP) and bisphenol A-bis(diphenyl phosphate) (BDP), respectively, whereas dietary exposure was the most important route for other chemicals.

Assessing human internal exposure to chemicals at different physical activity levels: A physiologically based kinetic (PBK) model incorporating metabolic equivalent of task (MET)

Physical activity levels have the potential to impact human internal exposure to environmental chemicals. However, the current lack of simple modeling approaches hinders the high-throughput screening of chemical exposure at different physical activity levels. To address this gap, this study proposes a straightforward model for assessing human internal exposure to chemicals. Our approach is based on the physiologically based kinetic (PBK) model and utilizes the metabolic equivalent of task (MET) to characterize internal exposure to chemicals at varying activity levels. To facilitate the application of this model, we have developed an Excel-based operation tool, allowing users to easily modify the MET value and generate simulation results for different physical activity levels. The simulation results demonstrate that as physical activity levels increase, the biotransfer factors (BTFs) of chemicals decrease, suggesting that higher physical activity levels reduce the bioaccumulation potential of chemicals. The intensified physical activity enhances the overall elimination kinetics of chemicals from the human body. However, the simulated concentrations of chemicals in the human body increase with higher physical activity levels, due to the significantly increased external exposure to chemicals, such as through inhalation. Our proposed modeling approach, along with the operational tool, enables high-throughput simulation of human chronic internal exposure to chemicals at different physical activity levels, where the findings can assist in screening chemicals for further health risk assessment. To accomplish this, the model incorporates certain assumptions and utilizes generic model input values. However, due to the intricate nature of the interaction between external and internal exposures at different physical activity levels, validating the simulation through experimental studies becomes challenging and is not performed in this study. For future studies, we recommend incorporating more MET-related physiological input variables, improving energy balance estimates, comprehending external exposure estimates, and conducting cohort studies to enhance and validate the proposed modeling approach.

Changes in perfluoroalkyl substances (PFAS) concentrations in human milk over the course of lactation: A study in Ronneby mother-child cohort

BACKGROUND

Little is known about how PFAS concentrations in human milk change over the course of lactation, although this is an important determinant of cumulative infant exposure from breastfeeding.

OBJECTIVE

To estimate changes in PFAS concentrations in human milk over the course of lactation in a population with a wide range of exposure from background-to high-exposed.

METHODS

We measured PFAS concentrations in colostrum and mature milk samples from women in the Ronneby Mother-Child Cohort. For each PFAS, we estimated the change in concentration from colostrum collected 3-4 days postpartum to mature milk collected 4-12 weeks postpartum using linear mixed-effects models. We evaluated whether this estimated change varied by quartiles of colostrum concentrations. In a subset of mothers with at least three mature milk samples, we estimated the change in concentration per month over the first eight months of lactation.

RESULTS

Our study included 77 mother-child pairs, of whom 74 had colostrum and initial mature milk samples and 11 had three or more repeated samples. The concentration change from colostrum to mature milk varied by PFAS. While PFOS increased by 21% (95% CI: 8.9, 35), PFOA decreased by 17% (95% CI: -28, -3.5) and PFHxS decreased by 12% (95% CI: -24, 3.3). In addition, PFAS concentrations tended to increase in women with lower colostrum levels, but decreased or remained the same in women with high colostrum concentrations. When we estimated changes over the course of lactation, we found that PFOA concentrations decreased the most (-12% per month; 95% CI: -22, -1.5), whereas PFHxS and PFOS showed small nonsignificant decreases.

CONCLUSIONS

Models for cumulative infancy exposure from breastfeeding need to account for differences in concentration trajectories by PFAS and possibly by maternal exposure level. Additional research is needed to evaluate the relative exposure from breastfeeding vs prenatal exposure, especially in highly exposed communities where breastfeeding guidance is urgently needed.

Determinants of flame retardants in non-occupationally exposed individuals - A review

Flame retardants (FRs) constitute a large group of different substances, some of which have been phased out of the market due to health concerns, while others are still used in many common consumer products to prevent fire hazards. This review addressed the determinants of FRs in non-occupationally exposed individuals based on surveys and questionnaire data. For this literature review, three databases (Scopus, Pubmed and Web of Knowledge) were searched by applying suitable terms, inclusion and exclusion criteria, producing a final selection of 78 articles for review. Based on these surveys there is epidemiological evidence for a significant association (p < 0.05) among human exposure and demographic factors, as well as a significant correlation between exposure to FRs and behavioural and environmental factors. Age, gender, housing characteristics, electrical and electronic equipment and mouthing behaviour (in children) play a leading role in human exposure to FRs as published studies demonstrated. However, the methodological differences among studies such as population size, questionnaire design and statistical analysis did not reveal a complete pattern of human exposure routes. Risk perception and communication are also discussed based on limited available data. Knowledge gaps and future perspectives relating to standardized protocols, elucidation of contamination sources, and risk response of health information from different target groups were also identified.

Human exposure and risk associated with trace element concentrations in indoor dust from Australian homes

This study examines residential indoor dust from 224 homes in Sydney, Australia for trace element concentrations measured using portable X-ray Fluorescence (pXRF) and their potential risk of harm. Samples were collected as part of a citizen science program involving public participation via collection and submission of vacuum dust samples for analysis of their As, Cr, Cu, Mn, Ni, Pb and Zn concentrations. The upper 95% confidence level of the mean values for 224 samples (sieved to <250 μm) were 20.2 mg/kg As, 99.8 mg/kg Cr, 298 mg/kg Cu, 247 mg/kg Mn, 56.7 mg/kg Ni, 364 mg/kg Pb and 2437 mg/kg Zn. The spatial patterns and variations of the metals indicate high homogeneity across Sydney, but with noticeably higher Pb values in the older areas of the city. Potential hazard levels were assessed using United States Environmental Protection Agency's (US EPA) carcinogenic, non-carcinogenic and Integrated Exposure Uptake Biokinetic (IEUBK) model human health risk assessment tools for children and adults. US EPA hazard indexes (HI) for Cr and Pb were higher than the safe level of 1.0 for children. HI > 1 suggests potential non-carcinogenic health effects. Carcinogenic risks were estimated for As, Cr and Pb whose carcinogenic slope factors (CSF) were available. Only the risk factor for Cr exceeded the US EPA's carcinogenic threshold (1 × 10^-4) for children. Children aged 1-2 years had the highest predicted mean child blood lead (PbB) of 4.6 μg/dL, with 19.2% potentially having PbB exceeding 5 μg/dL and 5.80% exceeding 10 μg/dL. The Cr and Pb levels measured in indoor dust therefore pose potentially significant adverse health risks to children.

Contribution of phthalates and phthalate monoesters from drinking water to daily intakes for the general population

Although phthalates (PAEs) are ubiquitous in drinking water, and phthalate monoesters (MPAEs) have been recognized as the bioactive metabolites of PAEs, little information is available regarding the occurrence of MPAEs in drinking water and the contributions of PAEs and MPAEs to human exposure. In this study, the concentrations of PAEs and MPAEs in 146 samples of drinking water collected from 24 cities throughout China were determined. The mean concentrations of dimethyl phthalate (DMP), diethyl phthalate (DEP), diisobutyl phthalate (DiBP), di-n-butyl phthalate (DnBP), and di-2-ethylhexyl phthalate (DEHP) were 14.31 ± 26.28, 5.905 ± 11.57, 103.8 ± 310.5, 595.9 ± 1794, and 178.2 ± 422.0 ng/L, respectively. Monomethyl phthalate (MMP), monoethyl phthalate (MEP), monoisobutyl phthalate (MiBP), mono-n-butyl phthalate (MnBP), and mono-2-ethylhexyl phthalate (MEHP) were detected in drinking water for the first time, at mean concentrations of 12.1 ± 18.0, 2.4 ± 5.8, 11.3 ± 37.2, 36.3 ± 103, and 9.9 ± 18.0 ng/L, respectively. The geometric mean concentrations of MMP, MEP, MiBP, MnBP, and MEHP in urine samples collected from 1040 participants from 16 cities were 10.1, 19.3, 29.6, 47.3, and 3.63 μg/g creatinine, respectively. The concentrations of PAEs and MPAEs in drinking water and daily intakes (DIs) of PAEs from nine cities where drinking water and urine samples were simultaneously collected were used to estimate the contributions from drinking water. The percentages of DMP, DEP, DiBP, DnBP, and DEHP from drinking water accounted for DIs of 0.60%, 0.049%, 1.26%, 2.76%, and 0.56%, respectively. The percentages of MMP, MEP, MiBP, MnBP and MEHP via intake of drinking water accounted for urinary concentrations of 0.86%, 0.032%, 0.14%, 0.089%, and 0.045%, respectively.

Tagged sources of short-chain chlorinated paraffins in China's marine environment and fish

Most emitters of short chain chlorinated paraffins (SCCPs) in China are located in eastern China, posing potential risks to the marine environment and food web. Here we employed a comprehensive atmospheric transport model combined with multiple environmental compartment exchange modules and a marine food web model to simulate levels and risks of SCCPs in the marine environment and fish in the Yellow Sea (YS), East China Sea (ECS), and South China Sea (SCS). Results unveiled a decreasing SCCP level in seawaters and sediments towards offshore. The modeled SCCP total (dry + wet) loadings to the three seawater bodies ranged from 0.0013 to 0.1635 mg/m²/season and gaseous diffusive deposition ranged from 43 to 4443 kg/month. The meteorological factors and secondary emission contributing to seasonal changes in SCCPs were also discussed. A tagging technique was used to trace origins of SCCPs, demonstrating that source proximity contributes most in SCCP contamination to these seawater bodies. Modeled SCCP levels in 5 marine fish in the YS, ECS, and SCS ranged from 23 to 111 ng/g. Our results showed the current SCCP levels in the marine environment and fish did not pose exposure risks to fish consumers for different age groups and genders. However, if consumed fish were harvested and imported from more seriously contaminated seawaters by SCCPs, the estimated dietary intake (EDI) would considerably increase.

Contamination levels and human health risk assessment of toxic heavy metals in street dust in an industrial city in Northwest China

This study investigated the content, distribution, and contamination levels of toxic metals (Cd, Cr, Cu, Pb, and Zn) in street dust in Lanzhou, an industrial city in Northwest China. Meanwhile, the risk these metals posed to the urban ecosystem and human health was also evaluated using the potential ecological risk index and human exposure model. Results showed that concentrations of these metals in the dust are higher than the background value of local soil, with Cu having the highest levels. The districts of Anning and Xigu had the most extreme levels of contamination, while Chengguan and Qilihe districts were lightly contaminated, which can be partly attributed to human activities and traffic densities. In comparison with the concentrations of selected metals in other cities, the concentrations of heavy metals in Lanzhou were generally at moderate or low levels. Heavy metal concentration increased with decreasing dust particle size. The pollution indices of Cr, Cd, Cu, Pb, and Zn were in the range of 0.289-2.09, 0.332-2.15, 1.38-6.21, 0.358-2.59, and 0.560-1.83 with a mean of 1.37, 1.49, 3.18, 1.48, and 0.897, respectively. The geo-accumulation index (I _geo) suggested that Zn in street dust was of geologic origin, while Cd, Cr, Pb, and Cu were significantly impacted by anthropogenic sources. The comprehensive pollution index showed that urban dust poses a high potential ecological risk in Lanzhou. Non-carcinogenic and carcinogenic effects due to exposure to urban street dust were assessed for both children and adults. For non-carcinogenic effects, ingestion appeared to be the main route of exposure to dust particles and thus posed a higher health risk to both children and adults for all metals, followed by dermal contact. Hazard index values for all studied metals were lower than the safe level of 1, and Cr exhibited the highest risk value (0.249) for children, suggesting that the overall risk from exposure to multiple metals in dust is low. The carcinogenic risk for Cd and Cr was all below the acceptable level (< 10^-6).

Human exposure assessment to antibiotic-resistant Escherichia coli through drinking water

Antibiotic-resistant bacteria (ARB) are a potential threat to human health through drinking water with strong evidence of ARB presence in post treated tap water around the world. This study examines potential human exposure to antibiotic-resistant (AR) Escherichia coli (E. coli) through drinking water, the effect of different drinking water treatments on AR E. coli and the concentration of AR E. coli required in the source water for the EU Drinking Water Directive (DWD) (Council Directive 98/83/EC, 0CFU/100ml of E. coli in drinking water) to be exceeded. A number of scenarios were evaluated to examine different water treatment combinations and to reflect site specific conditions at a study site in Europe. A literature search was carried out to collate data on the effect of environmental conditions on AR E. coli, the effect of different water treatments on AR E. coli and typical human consumption levels of tap water. A human exposure assessment model was developed with probability distributions used to characterise uncertainty and variability in the input data. Overall results show the mean adult human exposure to AR E. coli from tap water consumption ranged between 3.44×10^-7 and 2.95×10^-1cfu/day for the scenarios tested and varied depending on the water treatments used. The level of AR E. coli required in the source water pre-treatment to exceed the DWD varied between 1 and 5logcfu/ml, depending on the water treatments used. This can be used to set possible monitoring criteria in pre-treated water for potential ARB exposure in drinking water.

Concentrations of short- and medium-chain chlorinated paraffins in indoor dusts from malls in China: Implications for human exposure

Levels and distribution of short- and medium-chain chlorinated paraffins (SCCPs and MCCPs) were measured in indoor dusts from malls in China. The concentrations of SCCPs and MCCPs in dustfalls from a building material mall ranged from 6.0 to 361.4 μg g^-1 and from 5.0 to 285.9 μg g^-1, respectively. Much heavier contamination was found in central air conditioner filter (CACF) dusts from a newly opened shopping mall, with SCCP concentrations of 114.7-707.0 μg g^-1 and MCCP concentrations of 89.0-1082.9 μg g^-1. The C₁₃- and C₁₄-CPs were the dominant congeners, while the Cl₇ and Cl₈ groups were the major chlorine congeners in both kinds of dust samples. Significant correlation relationships (p ≤ 0.05) were found between ∑SCCPs and ∑MCCPs in CACF dusts and dustfalls. Varied exposure pathways including dust ingestion and dermal permeation have been evaluated. The average daily exposure doses of SCCPs and MCCPs for the adult in CACF dusts and dustfalls were estimated to be 0.394 and 0.150 μg kg^-1 day^-1, respectively. The toddler had higher exposure risks with 5.918 and 2.658 μg kg^-1 day^-1 in the shopping and building material malls, respectively. Dermal permeation was the predominated exposure pathway for the adult, while dust ingestion was suggested to be more important for the toddler due to hand-to-mouth contact.

Evaluating spatial distribution and seasonal variation of phthalates using passive air sampling in southern India

Usage of phthalates as plasticizers has resulted in worldwide occurrence and is becoming a serious concern to human health and environment. However, studies on phthalates in Indian atmosphere are lacking. Therefore, we studied the spatio-temporal trends of six major phthalates in Tamil Nadu, southern India, using passive air samplers. Phthalates were ubiquitously detected in all the samples and the average total phthalates found in decreasing order is pre-monsoon (61 ng m^-3) > summer (52 ng m^-3) > monsoon (17 ng m^-3). Largely used phthalates, dibutylphthalate (DBP) and diethylhexlphthalate (DEHP) were predominantly found in all the seasons with contribution of 11-31% and 59-68%, respectively. The highest total phthalates was observed in summer at an urban location (836 ng m^-3). Furthermore, through principal component analysis, potential sources were identified as emissions from additives of plasticizers in the polymer industry and the productions of adhesives, building materials and vinyl flooring. Although inhalation exposure of infants was higher than other population segments (toddlers, children and adults), exposure levels were found to be safe for people belonging to all ages based on reference dose (RfD) and tolerable daily intake (TDI) values. This study first attempted to report seasonal trend based on atmospheric monitoring using passive air sampling technique and exposure risk together.

Perspectives for integrating human and environmental exposure assessments

Integrated Risk Assessment (IRA) has been defined by the EU FP7 HEROIC Coordination action as "the mutual exploitation of Environmental Risk Assessment for Human Health Risk Assessment and vice versa in order to coherently and more efficiently characterize an overall risk to humans and the environment for better informing the risk analysis process" (Wilks et al., 2015). Since exposure assessment and hazard characterization are the pillars of risk assessment, integrating Environmental Exposure assessment (EEA) and Human Exposure assessment (HEA) is a major component of an IRA framework. EEA and HEA typically pursue different targets, protection goals and timeframe. However, human and wildlife species also share the same environment and they similarly inhale air and ingest water and food through often similar overlapping pathways of exposure. Fate models used in EEA and HEA to predict the chemicals distribution among physical and biological media are essentially based on common properties of chemicals, and internal concentration estimations are largely based on inter-species (i.e. biota-to-human) extrapolations. Also, both EEA and HEA are challenged by increasing scientific complexity and resources constraints. Altogether, these points create the need for a better exploitation of all currently existing data, experimental approaches and modeling tools and it is assumed that a more integrated approach of both EEA and HEA may be part of the solution. Based on the outcome of an Expert Workshop on Extrapolations in Integrated Exposure Assessment organized by the HEROIC project in January 2014, this paper identifies perspectives and recommendations to better harmonize and extrapolate exposure assessment data, models and methods between Human Health and Environmental Risk Assessments to support the further development and promotion of the concept of IRA. Ultimately, these recommendations may feed into guidance showing when and how to apply IRA in the regulatory decision-making process for chemicals.

Dermal permeation data and models for the prioritization and screening-level exposure assessment of organic chemicals

High-throughput screening (HTS) models are being developed and applied to prioritize chemicals for more comprehensive exposure and risk assessment. Dermal pathways are possible exposure routes to humans for thousands of chemicals found in personal care products and the indoor environment. HTS exposure models rely on skin permeability coefficient (KP; cm/h) models for exposure predictions. An initial database of approximately 1000 entries for empirically-based KP data was compiled from the literature and a subset of 480 data points for 245 organic chemicals derived from testing with human skin only and using only water as a vehicle was selected. The selected dataset includes chemicals with log octanol-water partition coefficients (KOW) ranging from -6.8 to 7.6 (median=1.8; 95% of the data range from -2.5 to 4.6) and molecular weight (MW) ranging from 18 to 765g/mol (median=180); only 3% >500g/mol. Approximately 53% of the chemicals in the database have functional groups which are ionizable in the pH range of 6 to 7.4, with 31% being appreciably ionized. The compiled log KP values ranged from -5.8 to 0.1cm/h (median=-2.6). The selected subset of the KP data was then used to evaluate eight representative KP models that can be readily applied for HTS assessments, i.e., parameterized with KOW and MW. The analysis indicates that a version of the SKINPERM model performs the best against the selected dataset. Comparisons of representative KP models against model input parameter property ranges (sensitivity analysis) and against chemical datasets requiring human health assessment were conducted to identify regions of chemical properties that should be tested to address uncertainty in KP models and HTS exposure assessments.

Occurrence and human exposure of parabens and their chlorinated derivatives in swimming pools

As an emerging group of endocrine-disrupting chemicals, parabens have attracted growing attention due to their potential effects on human health. In the present study, the occurrence and distribution of eight parabens, four chlorinated parabens, and their common hydrolysis product, p-hydroxybenzoic acid (PHBA), were investigated in 39 swimming pools in Beijing, China. Methyl paraben and propyl paraben were the predominant compounds in swimming pools, accounting for 91.2 % of the total parabens. It is noteworthy that octyl paraben, a paraben with longer chain, was firstly detected in this study. There were several factors affecting the levels of parabens among the 39 swimming pools. The concentrations of parabens and chlorinated derivatives detected in indoor pools (144 ng L(-1)) were roughly 20-fold higher than those in outdoor pools (6.78 ng L(-1)). Hotel pools appear to present higher level of target compounds (361 ng L(-1)) than that in health club (228 ng L(-1)), municipal (130 ng L(-1)), school (75.6 ng L(-1)), and community pools (63.0 ng L(-1)). Moreover, the level of these compounds in pools during weekends (174 ng L(-1)) was much higher than that during weekdays (52.3 ng L(-1)). The dynamics of target compounds were also investigated to provide a general trend of the level of parabens in a school indoor swimming pool during a 14-week period. Human exposure assessment was conducted to estimate the potential risk of exposure to parabens and their chlorinated derivatives in swimming pools. Considering the total exposure dose of multiple parabens, human exposure to parabens from the water of swimming pools is negligible. However, the threat of these parabens to children in swimming pool should be concerned.