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.

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).

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.

Occurrence, distribution and potential risk to infants of neonicotinoids in breast milk: A case study in Hangzhou, China.

The pervasive use of neonicotinoid insecticides (neonics) has led to increasing concerns regarding the potential health risks associated with them. Breast milk is the main food source of infants, and thus, the presence of chemicals in breast milk has a greater impact on infant health. However, there have only been few reports regarding the presence of neonics in breast milk. Herein, eight neonics were detected in breast milk samples using ultraperformance liquid chromatography-mass spectrometry and their Pearson correlation was analyzed. The potential health risks of neonics to infants were assessed using the relative potency factor (RPF) method. The results revealed that neonics were widely detected in the breast milk samples from Hangzhou, with at least one neonics being detected in >94 % of the breast milk samples. The most frequently detected neonics included thiamethoxam (70.8 %) followed by imidacloprid (IMI) (62.0 %) and clothianidin (46.0 %). The residual concentrations of neonics in the breast milk samples ranged from

Estimating arsenic biotransfer factors from feed to chicken: a viable approach to animal feed risk assessment.

Reliable biotransfer factor (BTF) data are critical for animal-feed studies in human risk assessment. A wide range of BTF values have been reported (0.0015-0.83 d/kg), expressed as the ratio of total arsenic (tAs) concentration (µg/kg) in chicken to daily intake rate (µg/d) of tAs in feed (tAs/tAs). Data on inorganic As (iAs) for chicken meat and tAs concentrations for feed were obtained from our related study. Using the linear regression technique developed in this study, we estimated the BTF as 0.016 d/kg, as iAs/tAs (R2 > 0.7702) and 0.55 d/kg as tAs/tAs (R2 = 0.9743) for whole chicken meat. From a mass-balance perspective, we suggest that tAs be used as the denominator for the BTF unit. To illustrate our feed-risk assessment method, we analyzed commercial feeds for tAs concentration (n = 79). Consumption data for the general population (n = 2479) were obtained from a Taiwanese total diet study. Bivariate Monte Carlo simulations (n = 10,000) showed that the 95th percentile (P95) of estimated daily intake (EDI) was 0.002 µg/kg body weight (bw)/d as iAs (< the benchmark dose lower limit of 3.0 µg/kg bw/d). Our results thus show that the commercial chicken feeds assessed in this study are of low health concern for the general Taiwanese population. We discuss the factors that may have affected the assessment, such as the type of animals investigated, type of feeds, feed tested, type of chemical species used for BTF estimation and statistical approach.

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.

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.

Acute human exposure assessment to tetrahydrocannabinol (Δ9-THC).

Delta-9-tetrahydrocannabinol (Δ9-THC) is a naturally occurring psychoactive compound derived from the hemp plant Cannabis sativa. In 2015, EFSA established an acute reference dose (ARfD) of 1 µg/kg body weight (bw) for Δ9-THC and assessed acute dietary exposure from milk and dairy products. This resulted at the most 3% and 13% of the ARfD for adults and toddlers, respectively. Following the European Commission Recommendation 2016/2115 on the monitoring of the presence of Δ9-THC in food and the issuing of a new mandate, EFSA assessed the acute human exposure to Δ9-THC. 'Standard' food categories were used as proxies for consumption of hemp and hemp-based products. Twelve independent scenarios based on single food categories were considered and acute exposure was assessed for consumption days only for all age groups excluding infants. Occurrence data for Total-Δ9-THC (588 samples in total) were used for this assessment up to the highest reliable percentile for each food category. The EFSA ARfD of 1 µg/kg bw was exceeded in the adult high consumers of most considered hemp and hemp-containing products, under the lower-bound (LB) and upper-bound (UB) scenario. At the UB, acute exposure in adult high consumers was estimated based on the highest reliable percentile of occurrence, for Hemp seeds (P95, up to 9 µg/kg bw), Hemp oil (P95, up to 21 µg/kg bw), Tea (Infusion) (P95, up to 208 µg/kg bw), Breakfast cereals (P50, up to 1.3 µg/kg bw), Pasta (Raw) (P75, up to 6.4 µg/kg bw), Bread and rolls (P75, up to 1.3 µg/kg bw), Bread and rolls from hemp flour (P90, up to 4.1 µg/kg bw), Cereal bars (P50, up to 0.3 µg/kg bw), Fine bakery wares (P75, up to 5.1 µg/kg bw), Chocolate (Cocoa) products (P75, up to 1.1 µg/kg bw), Energy drinks (P75, up to 0.2 µg/kg bw), Dietary supplements (P75, up to 9.9 µg/kg bw), Beer and beer-like beverages (P90, up to 41 µg/kg bw). The use of proxies for the consumption of hemp and hemp-containing products, the limited number of occurrence data and the analytical limitations in the quantification of Δ9-THC represent the most important sources of uncertainty. Overall, exposure estimates presented in this report are expected to represent an overestimation of acute exposure to Δ9-THC in the EU.

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 ±â€¯26.28, 5.905 ±â€¯11.57, 103.8 ±â€¯310.5, 595.9 ±â€¯1794, and 178.2 ±â€¯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 ±â€¯18.0, 2.4 ±â€¯5.8, 11.3 ±â€¯37.2, 36.3 ±â€¯103, and 9.9 ±â€¯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.

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.

The Impact of Activity-Based Mobility Pattern on Assessing Fine-Grained Traffic-Induced Air Pollution Exposure.

Quantifying the air pollution and health impacts of transportation plans provides decision makers with valuable information that can help to target interventions. However, a large number of environmental epidemiological research assumes exposures of static populations at residential locations and does not consider the human activity patterns, which may lead to significant estimation errors. This study uses an integrated modeling framework to predict fine-grained air pollution exposures occurring throughout residents' activity spaces. We evaluate concentrations of fine particulate matter (PM2.5) under a regional transportation plan for Sacramento, California, using activity-based travel demand model outputs, vehicle emission, and air dispersion models. We use predicted air pollution exposures at the traffic analysis zone (TAZ) level to estimate residents' exposure accounting for their movements throughout the day to assess the impact of activity-based mobility pattern on air pollution exposure. Results of PM2.5 exposures estimated statically (at residential locations) versus dynamically (over residents' activity-based mobility) demonstrates that the two methods yield statistically significant different results (p < 0.05). In addition, the comparison conducted in different age groups shows that the difference between these two approaches is greater among youth and working age residents, whereas seniors show a similar pattern using both approaches due to their lower rates of travel activity.

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.

A Pilot Study to Examine Exposure to Residential Radon in Under-Sampled Census Tracts of DeKalb County, Georgia, in 2015.

While DeKalb County, Georgia, offers free radon screening for all eligible residents, portions of the county remain relatively under-sampled. This pilot study focused on 10% of the census tracts in the county with the lowest proportion of radon testing; most were in southern DeKalb County. In total, 217 households were recruited and homes were tested for indoor radon concentrations on the lowest livable floor over an eight-week period from March-May 2015. Tract-level characteristics were examined to understand the differences in socio-demographic and economic factors between the pilot study area and the rest of the county. The pilot study tracts had a higher proportion of African Americans compared to the rest of DeKalb County (82% versus 47%). Radon was detected above 11.1 Bq/m³ (0.3 pCi/L) in 73% of the indoor samples and 4% of samples were above 148 Bq/m³ (4 pCi/L). Having a basement was the strongest predictive factor for detectable and hazardous levels of radon. Radon screening can identify problems and spur homeowners to remediate but more research should be done to identify why screening rates vary across the county and how that varies with radon levels in homes to reduce radon exposure.

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.

Margin of safety for two UV filters estimated by in vitro permeation studies mimicking consumer habits: Effects of skin shaving and sunscreen reapplication.

Sunscreens are intended to work on the skin. To be both efficient and safe, the lowest possible percutaneous permeation of UV filters should occur. The potential for systemic absorption of Benzophenone-3 (BP3, 10%) and Ethylhexyl Triazone (EHT, 5%) in a silicone-based water-in-oil emulsion was assessed in vitro using a full-thickness porcine-ear skin mimicking in-use conditions. The estimated Systemic Exposure Dose (SED) after the sunscreen application at 1.0 mg/cm2 for 6 h (i) on the face; (ii) on the whole-body skin, was (i) 136 and 30; (ii) 4200 and 933 µg/kg_bw/d for BP3 and EHT, respectively. Reapplication does not mean the double risk; the SED values were only 1.40-1.37-fold greater. Skin shaving increased BP3 and EHT bioavailability 1.38 and 1.80-fold, respectively. Margin of Safety values were estimated according to guidelines applicable for European Union. For three realistic exposure scenarios, MoS of 48, 34 and 34 for BP3 in the sunscreen applied on the whole-body indicate some concerns regarding the safety for consumers (MoS<100). Despite undeniable functional benefits in sunscreens, BP3 concentration allowed in EU cosmetics (max. 10%) should be reviewed, especially in products intended for whole-body applications. The development of new UV filters should be focused on their specific physico-chemical properties.

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.