Non-dietary Exposure Research Articles

Assessing risks to adults and preschool children posed by PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) during a biomass burning episode in Northern Thailand

To investigate the potential cancer risk resulting from biomass burning, polycyclic aromatic hydrocarbons (PAHs) bound to fine particles (PM2.5) were assessed in nine administrative northern provinces (NNP) of Thailand, before (N-I) and after (N-II) a haze episode. The average values of Σ3,4-ring PAHs and B[a]PEquivalent concentrations in world urban cities were significantly (p<0.05) much higher than those in samples collected from northern provinces during both sampling periods. Application of diagnostic binary ratios of PAHs underlined the predominant contribution of vehicular exhaust to PM2.5-bound PAH levels in NNP areas, even in the middle of the agricultural waste burning period. The proximity of N-I and N-II values in three-dimensional (3D) principal component analysis (PCA) plots also supports this conclusion. Although the excess cancer risk in NNP areas is much lower than those of other urban area and industrialized cities, there are nevertheless some concerns relating to adverse health impacts on preschool children due to non-dietary exposure to PAHs in home environments.

Arsenic: bioaccessibility from seaweed and rice, dietary exposure calculations and risk assessment

Arsenic is a metalloid that occurs in food and the environment in different chemical forms. Inorganic arsenic is classified as a class I carcinogen. The inorganic arsenic intake from food and drinking water varies depending on the geographic arsenic background. Non-dietary exposure to arsenic is likely to be of minor importance for the general population within the European Union. In Europe, arsenic in drinking water is on average low, but food products (e.g. rice and seaweed) are imported from all over the world including from regions with naturally high arsenic levels. Therefore, specific populations living in Europe could also have a high exposure to inorganic arsenic due to their consumption pattern. Current risk assessment is based on exposure via drinking water. For a good estimation of the risks of arsenic in food, it is important to investigate if the bioavailability of inorganic arsenic from food is different from drinking water. The present study further explores the issue of European dietary exposure to inorganic arsenic via rice and seaweed and its associated health risks. The bioavailability of inorganic arsenic was measured in in vitro digestion experiments. The data indicate that the bioavailability of inorganic arsenic is similar for rice and seaweed compared with drinking water. The calculated dietary intake for specific European Union populations varied between 0.44 and 4.51 µg kg–1 bw day–1. The margins of exposure between the inorganic intake levels and the BMDL0.5 values as derived by JECFA are low. Decreasing the intake of inorganic arsenic via Hijiki seaweed could be achieved by setting legal limits similar to those set for rice by the Codex Alimentarius Commission in July 2014.

Mouthing activity data for children aged 7 to 35 months in Taiwan.

Young children's mouthing activities thought to be among the most important exposure pathways. Unfortunately, mouthing activity studies have only been conducted in a few countries. In the current study, we used videotaping and computer-based translating method to obtain mouthing activity data for 66 children aged 7-35 months in Taiwan. The median indoor hand-to-mouth and object-to-mouth frequencies were 8.91 and 11.39 contacts/h, respectively. The median indoor hand-to-mouth and object-to-mouth hourly contact durations were 0.34 and 0.46 min/h, respectively. The indoor object-to-mouth activities were significantly and negatively correlated with age. Children aged 12 to <24 months in the current study had lower indoor hand-to-mouth and object-to-mouth frequencies than children of same age group in the United States. We also found that indoor mouthing duration with pacifier was significantly and negatively correlated with indoor mouthing duration with other non-dietary objects. The results of the current study indicate that the mouthing behaviors may be different between different countries or populations with different ethnic or lifestyle characteristics. We conclude that using hand-to-mouth frequency values from the current literature may not be most reliable for estimating non-dietary exposures of young children living in Taiwan or even in other similar Asian countries.

Is pesticide exposure a cause of obstructive airways disease?

A systematic review was performed to identify any associations between pesticide exposure and the occurrence (both prevalence and incidence) of airways disease (asthma and chronic obstructive pulmonary disease) and wheezing symptoms. PubMed, MEDLINE, Embase, Scopus, CINAHL, Google Scholar and the Cochrane Database of Systematic Reviews were searched between September 2010 and October 2010 for papers with the inclusion criteria of English language, published after 1990, peer-reviewed and nondietary exposure. From a total of 4390 papers identified, 42 were included after initial assessment of content. After evaluating the included studies for quality, those considered to be at high risk of bias were excluded, leaving a total of 23 relevant papers. Results suggest that exposure to pesticides may be associated with prevalent asthma, but methodological issues, such as cross-sectional/case-control design, measurements of exposure and limited adjustment for confounders, limit the strength of the evidence base in this area. The association between pesticide exposure and asthma appears to be more evident and consistent in children than in adults. Exposure to pesticides may be associated with COPD; however, the strength of evidence for an association with COPD is weaker than for asthma. As the exposure metrics within each health end-point varied across studies, no meta-analyses were carried out.

Dioxin-related compounds in breast milk of women from Vietnamese e-waste recycling sites: Levels, toxic equivalents and relevance of non-dietary exposure

Although informal e-waste recycling sites (EWRSs) are hotspots of both polychlorinated and polybrominated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs and PBDD/Fs), human exposure to the latter has not been studied in details. This study investigated the accumulation levels and profiles of dioxin-related compounds (DRCs) in breast milk samples from women living in two Vietnamese EWRSs and estimated the intake contribution from e-waste-related exposure. Screening results using Dioxin-Responsive Chemically Activated LUciferase gene eXpression assay (DR-CALUX) showed higher dioxin-like (DL) activities in samples from the EWRS Bui Dau than in those from the EWRS Trang Minh and a reference site (2.3–10 vs 1.7–4.8 and 0.60–5.7pg CALUX-TEQ/g lipid, n=10, 6 and 9, respectively). Chemical analysis results of selected samples show that the WHO-TEQ levels of PCDD/Fs, DL-PCBs and PBDD/Fs in EWRS samples were not significantly higher than in those from the reference site (0.22–7.4 vs 1.1–3.0pg/g lipid) and within the Vietnamese background range, but women involved in recycling accumulated higher concentrations of PCDFs (13–15 vs 2.3–8.8pg/g lipid) and PBDFs (1.1–1.5 vs <1.1pg/g lipid). By comparing the DRC profile in milk of these women with the reported profile in house dust from the same site, dust ingestion was estimated to contribute most of the intake for tetraBDF, 37 per cent to 55 per cent for penta–octaCDFs, but less than twenty per cent for PCDDs and DL-PCBs, and 26 per cent for total WHO-TEQs. The DL activities in some EWRS milk samples were not fully explained by chemical data, suggesting contribution from unidentified compounds. The estimated WHO-TEQ intake doses for breastfed infants (1.3–33pg/kg/d) mostly exceeded the tolerable value, especially for those living in the EWRSs; and unidentified DRCs might increase further the dioxin-related health risk.

Heavy metals in vegetables and respective soils irrigated by canal, municipal waste and tube well waters

Heavy metal contamination in the food chain is of serious concern due to the potential risks involved. The results of this study revealed the presence of maximum concentration of heavy metals in the canal followed by sewerage and tube well water. Similarly, the vegetables and respective soils irrigated with canal water were found to have higher heavy metal contamination followed by sewerage- and tube-well-watered samples. However, the heavy metal content of vegetables under study was below the limits as set by FAO/WHO, except for lead in canal-water-irrigated spinach (0.59 mg kg−1), radish pods (0.44 mg kg−1) and bitter gourd (0.33 mg kg−1). Estimated daily intakes of heavy metals by the consumption of selected vegetables were found to be well below the maximum limits. However, a complete estimation of daily intake requires the inclusion of other dietary and non-dietary exposure sources of heavy metals.

Concentrations of polybrominated diphenyl ethers (PBDEs) in central air-conditioner filter dust and relevance of non-dietary exposure in occupational indoor environments in Greece

Polybrominated Diphenyl Ethers (PBDEs) are ubiquitous in the indoor environment owing to their use in consumer products and various studies around the world have found higher concentrations indoors than outdoors. Central air conditioner (A/C) systems have been widely used in many workplaces, therefore, studying of PBDEs in central A/C filter dust is useful to better understand the occurrences and health implications of PBDEs in indoor environments. The present study examined the occurrence of PBDEs in central A/C filter dust collected from various workplaces (n = 20) in Thessaloniki, Greece. The sum concentrations of 21 target congeners (∑21PBDE) in A/C dust ranged between 84 and 4062 ng g−1 with a median value of 1092 ng g−1, while BDE-209 was found to be the most abundant BDE congener. The daily intake via dust ingestion of PBDEs estimated for the employees of the occupational settings ranged from 3 to 45 ng day−1 (median 12 ng day−1).

Pesticide Risk Perceptions, Knowledge, and Attitudes of Operators, Workers, and Residents: A Review of the Literature

ABSTRACT The literature on the risk perceptions, knowledge levels, and attitudes of operators, workers, and residents in relation to non-dietary exposure to agricultural pesticides is reviewed. No literature was identified in relation to bystander exposure. Research has primarily been conducted on participants in developing countries and migrant workers in the United States. For operators and workers, illiteracy, poverty, and a perception that exposure to pesticides is an inevitable part of their work results in limited adoption of safety precautions while using and storing pesticides. As a result, risk communication activities aimed at operator and workers need to take account of the wider socioeconomic and cultural conditions in which workers and operators are working and living. There is less research focused on residents’ and bystanders’ perceptions, attitudes, and behaviors. The lack of European data in general, and residents’ and bystanders’ data in particular, represents a knowledge gap that is pertinent to emerging EU legislation requiring residents’ and bystanders’ inclusion in pesticide risk assessment. This review provides a comprehensive overview that can assist policy-makers, and risk communicators in the development of targeted training and awareness-raising material for operators, workers, bystanders, and residents. Areas for future research are suggested.

Health risk assessment of exposure to polybrominated diphenyl ethers (PBDEs) contained in residential air particulate and dust in Guangzhou and Hong Kong

Polybrominated diphenyl ethers (PBDEs) were measured in air particulate PM2.5 (less than 2.5 μm), TSP (Total Suspend Particle) and dust samples from different households of two major urban centers of Pearl River Delta (PRD). ∑PBDEs in PM2.5 of households in Guangzhou (GZ) (52.9–2.03 × 103 pg m−3 mean 239 pg m−3) were significantly higher than Hong Kong (HK) (0.25–160 pg m−3, mean 43.8 pg m−3). Higher ∑PBDEs occurred in indoor TSP, ranging between 117 and 1.14 × 103 pg m−3, with a median of 333 pg m−3. BDE-209 was the largest contributor to PBDEs contained in household dust, PM2.5 and TSP samples of GZ. Among the particles in household environment, PM2.5 accumulated the highest PBDEs, especially BDE-209. The constant Cparticle/Cdust values suggested that sorption is the dominant mechanism through which PBDEs are associated with settled dust and airborne particles. PBDEs were fairly uniform from urban sites to suburban sites, indicating the predominant indoor sources of PBDEs. Compared with indoor PM2.5, indoor dust ingestion made an important contribution of particle associated PBDEs exposure for adults (25 years old) and toddlers (1–2 years old). Non-dietary exposure dominated total PBDEs exposure, accounting for 91.8–99.0% exposure dose for toddlers and 45.1–82.2% for adults. Dust ingestion (69.3–96.1%) was the predominant PBDEs exposure route for toddlers.

Assessing spatial distribution, sources, and human health risk of organochlorine pesticide residues in the soils of arid and semiarid areas of northwest China

Thirty-two topsoil samples were collected to analyze the residue levels of organochlorine pesticides (OCPs) in topsoil of arid and semiarid areas of northwest China in 2011. Results showed that DDTs were the dominant contaminants with a mean concentration of 12.52ng/g. The spatial distribution characteristics indicated that α-hexachlorocyclohexanes (HCHs) were mainly used in rural sites, whereas hexachlorobenzene (HCB) and endosulfan were detected mostly in urban areas. DDTs, heptachlor, and chlordane were found almost equally in both urban and rural areas. Source identification revealed that the current levels of HCHs in soils were attributable to the residues from their historical use and fresh usage of lindane (γ-HCH). DDTs were mainly from historical use and fresh usage of dicofol, and HCB was emitted from the chemical industry. It was also found that the current soil levels of heptachlor were mainly from its historical usage, endosulfan from fresh input, and chlordane from long-range atmospheric transport, respectively. The noncarcinogenic health risk assessment with a model was also conducted using USEPA standards for adults and children. Results indicated that health risk under nondietary exposure to OCPs decreased in the sequence of ΣDDT > ΣHCH > HCB > Σheptachlor > Σendosulfan > Σchlordane. According to the reference dose from the USEPA, the health risk under nondietary exposure to OCPs in the soil samples was at a relatively safe level.

ASSESSING EXPOSURES TO PERSISTENT ORGANIC POLLUTANTS IN A GROUP OF CALIFORNIA FIREFIGHTERS

Background.Firefighters are likely to be exposed to a variety of toxic chemicals, including persistent organic pollutants (POPs), while responding to structural, vehicular or wildland fires or to industrial accidents and chemical spills. While previous studies have measured chemicals at fire sites, few have evaluated serum concentrations of POPs in firefighters. Aim. This pilot biomonitoring study assessed body burdens of selected POPs in a group of California firefighters and tested protocols that could be used in larger occupational biomonitoring studies. Methods. In 2010-11we recruited, interviewed and collected blood samples from 101 Southern California firefighters. Serum was separated and analyzed for polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) by gas chromatography/high resolution mass spectrometry using isotope dilution. Questionnaire data were analyzed using SAS. Results. All chemical classes were detected in all samples. Median concentrations (all in ng/g lipid) ranged from 1-182 for OCPs; 1-15 for PCBs and 1-30 for PBDEs. Most samples (75% and 90%, respectively) exceeded the 50th percentile of NHANES (2003-04) for PBDE-47 and PBDE-153, and 4% exceeded the 95th percentile for both. Correlations between PCBs and OCPs were moderate while PBDEs showed low and statistically non-significant correlations with PCBs or OCPs, pointing to non-dietary exposure routes for PBDEs. PCB and OCP concentrations were highest among older participants, while concentrations of almost all PBDEs were highest in those with 10-20 years of firefighting experience. Preliminary analyses showed certain practices such as use/storage of protective equipment and duty assignments to be associated with elevated serum PBDEs. Conclusions. In this pilot study PBDE concentrations in firefighters’ serum were the highest yet measured in California adults, known for high levels of flame retardants.

Modeling exposures to organophosphates and pyrethroids for children living in an urban low-income environment

Pesticide exposure in urban low-income residential environments may be elevated as a result of persistent application due to severe pest infestation. Children living in this environment may be a sensitive subpopulation for these non-dietary exposures, due to their physiological and behavioral differences. In this study, we provide an exposure modeling framework to simulate exposures for children in this environment and assess dominant exposure routes and sources of exposure variability, in order to characterize factors that influence risk. We use a dataset of pesticide measurements collected in 42 low-income dwellings, including vacuum dust and floor wipe samples from kitchens and living rooms. We fit distributions to the concentration measurements for the organophosphates measured, chlorpyrifos and diazinon, and the most prevalent pyrethroids (permethrin, cypermethrin, and cyfluthrin), and simulated 1000 homes from the distributions. Concentration measurements were then connected with activity pattern data, short-term dermal and ingestion exposures and absorbed doses were simulated for children ages 1–5 years. For both pesticide groups, exposure values ranged widely, with concentration values contributing most significantly to exposure variability, although approximately 20-fold variability was attributable to exposure factors alone. In addition, upper percentile exposed children usually had both higher concentrations as well as greater influences from exposure and dose factors. Differences were also seen across pesticide groups in dominant exposure pathways. Our analyses indicate a profile of factors that describe individuals likely to receive high doses of one or multiple pesticides and could allow for more targeted intervention strategies. More generally, this work provides a standard framework to evaluate and describe exposures to prevalent residential pesticides via multiple pathways.

Size fraction effect on phthalate esters accumulation, bioaccessibility and in vitro cytotoxicity of indoor/outdoor dust, and risk assessment of human exposure

Indoor and outdoor dusts from two urban centers in the Pearl River Delta, China, were analyzed and phthalate esters varied from 4.95 to 2220μgg−1 in indoor dust, significantly higher than outdoor dust (1.70–869μgg−1). Di-2-ethylhexyl phthalate (DEHP) was the dominant phthalate found and the highest distribution factor (DF) (1.56±0.41) was noted in the <63μm fraction (p<0.05). In vitro cytotoxicity of dust extract on human T cell lymphoblast leukemic cell line (CCRF-CEM) indicated by Lethal Concentration 50 (LC50) decreased with particle size. The power model was found as a better fit for explaining the relationship between LC50 and phthalates (R2=0.46, p<0.01). Bioaccessibility of phthalates in dust varied with different particle sizes, with the greatest bioaccessible fraction (2.49–38.6%) obtained in <63μm. Risk assessment indicated that indoor dust ingestion accounted for the major source for DEHP exposure (81.4–96.4% of non-dietary exposure and 36.5% of total exposure), especially for toddlers. The cancer risks associated with DEHP via home dust were high (10−6–10−4), with 10% of houses estimated with unacceptable risks (>10−4). After corrected with the bioaccessibility of phthalates, the cancer risks of dust exposure were moderate (10−7–10−5).

Evaluation of Predictive Algorithms Used for Estimating Potential Postapplication, Nondietary Ingestion Exposures to Pesticides Associated with Children's Hand-to-Mouth Behavior

Postapplication exposure assessment related to indoor residential application of pesticide products requires consideration of product use information, application methods, chemical-specific deposition, time-dependent availability and transferability of surface residues, reentry time, and temporal location and macro- and microactivity/behavior patterns (Baker et al., 2000). Children's mouthing behavior results in potential postapplication exposure to available pesticides in treated microenvironments through the nondietary ingestion route, in addition to the dermal or inhalation routes. Children's activities and associated behaviors may result in multiple or repeat contact of dermal areas (clothed and unclothed body areas and hands) with treated surfaces, or surfaces that may have indirect sources of residues. Further, some surfaces contacted may have transferable pesticide residues and others may not. Transfer of residues from the indoor residential environment to the dermal surface (e.g., hands) of an individual has been assumed to be linear as a function of time and number of contacts. However, studies suggest that this transfer process to the hands and other body areas may be rapidly saturable. In the most recent U.S. Environmental Protection Agency (EPA), Office of Pesticide Programs (OPP) “Residential Exposure Assessment Standard Operating Procedures” (U.S. EPA, 2012), the input variable for the number of dermal contacts (with treated surfaces) is an exponent, making the relationship nonlinear. Further, removal processes such as hand washing and transfer to untreated surfaces are important to consider. Predictive algorithms for estimating children's hand-to-mouth-related incidental ingestion exposures post pesticide application have been developed by the EPA/OPP and incorporated into probabilistic models. A review of literature addressing variables used to estimate potential incidental ingestion exposure is presented. Data relevant to input variables for predictive algorithms are discussed, including the results of a multiyear, pesticide transferable residue measurement program conducted by the Non-Dietary Exposure Task Force (NDETF) and the associated distributional characterization for this key variable. Sources of conservative bias in current hand-to-mouth, incidental ingestion exposure estimation and the role of biomonitoring to evaluate predicted exposures are discussed.

Risk assessment of non-dietary exposure to polycyclic aromatic hydrocarbons (PAHs) via house PM2.5, TSP and dust and the implications from human hair

To evaluate the cancer risk due to non-dietary PAHs exposure in home environment (inhalation and ingestion), exposure to fine particles (PM2.5) and polycyclic aromatic hydrocarbons (PAHs) of PM2.5, total suspend particles (TSP) and dust in homes at two urban centers of Pearl River Delta were assessed. House PM2.5 bound PAHs in Guangzhou (GZ) ranged from 10.0 to 61.9 ng m−3 and 0.72 to 8.15 ng m−3 in Hong Kong (HK). PAH profiles found in PM2.5, TSP and dust were different than that in hair (dominated by Nap and Phe). Pyr and Flu in house dust significantly correlated with that in hair (r = 0.69; 0.55, p < 0.05) but no correlation was found between PAHs in hair and PM2.5. High correlation coefficients (r2 = 0.97/0.95, p < 0.01) were noted between dibenzo(a,h)anthracene (DBA) and Toxicity Equivalent Concentrations (TEQs) of dust and PM2.5. The lung cancer risks based on PM2.5 bound PAHs exposure in houses of GZ (10−5–10−4) were significantly higher than those of HK (10−6–10−5), which were also significantly higher than the cancer risks associated with house dust intake (10−7–10−5) in GZ. PAHs exposure via non-dietary route (PM2.5 and dust) was found to be 1–3 times higher than fish consumption for children and contributed to 52–76% of total PAHs intake for children and 24–50% for adults in GZ.

Contamination of indoor dust and air by polychlorinated biphenyls and brominated flame retardants and relevance of non-dietary exposure in Vietnamese informal e-waste recycling sites

This study investigated the occurrence of polychlorinated biphenyls (PCBs), and several additive brominated flame retardants (BFRs) in indoor dust and air from two Vietnamese informal e-waste recycling sites (EWRSs) and an urban site in order to assess the relevance of these media for human exposure. The levels of polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), 1,2-bis-(2,4,6-tribromophenoxy)ethane (BTBPE) and decabromodiphenyl ethane (DBDPE) in settled house dust from the EWRSs (130–12,000, 5.4–400, 5.2–620 and 31–1400ngg−1, respectively) were significantly higher than in urban house dust but the levels of PCBs (4.8–320ngg−1) were not higher. The levels of PCBs and PBDEs in air at e-waste recycling houses (1000–1800 and 620–720pgm−3, respectively), determined using passive sampling, were also higher compared with non-e-waste houses. The composition of BFRs in EWRS samples suggests the influence from high-temperature processes and occurrence of waste materials containing older BFR formulations. Results of daily intake estimation for e-waste recycling workers are in good agreement with the accumulation patterns previously observed in human milk and indicate that dust ingestion contributes a large portion of the PBDE intake (60%–88%), and air inhalation to the low-chlorinated PCB intake (>80% for triCBs) due to their high levels in dust and air, respectively. Further investigation of both indoor dust and air as the exposure media for other e-waste recycling-related contaminants and assessment of health risk associated with exposure to these contaminant mixtures is necessary.

Phthalates in indoor dust in Kuwait: implications for non-dietary human exposure

Phthalates are semivolatile organic compounds with a ubiquitous environmental distribution. Their presence in indoor environments is linked to their use in a variety of consumer products such as children's toys, cosmetics, food packaging, flexible PVC flooring among others. The goal of this study was to investigate the occurrence and concentration of phthalates in dust from homes in Kuwait and to assess non-dietary human exposure to these phthalates. Dust samples were randomly collected from 21 homes and analyzed for eight phthalates. The concentrations of total phthalates were log normally distributed and ranged from 470 to 7800 μg/g. Five phthalates [Di(2-ethylhexyl) phthalate (DEHP), Di-n-octyl phthalate (DnOP), Di-n-butyl phthalate (DBP), Benzyl butyl phthalate (BzBP), and Dicyclohexyl phthalate (DcHP)] were routinely detected. The major phthalate compound was DEHP at a geometric mean concentration of 1704 μg/g (median, 2256 μg/g) accounting for 92% of the total phthalates measured. Using the measured concentrations and estimates of dust ingestion rates for children and adults, estimated human non-dietary exposure based on median phthalate concentrations ranged from 938 ng/kg-bd/day for adults to 13362 ng/kg-bd/day for toddlers. The difference in exposure estimates between children and adults in this study supports previous reports that children are at greater risk from pollutants that accumulate indoors.

Methodology to Capture Children's Non-Dietary Ingestion Exposure Activities During Meal Events

ABSTRACT During meal events, a child's food can be contaminated through contacts with objects and surfaces, and/or unwashed hands that have chemical residues, increasing ingestion exposure of contaminants for the child. This is not surprising, given that very young children eat more with the hands than adults, are active, and play with toys and objects while eating. In addition, children's unwashed hands and toys are commonly inserted into their mouths during meal events, increasing exposure. By observing children during their meal events, information can be gathered on the frequency and duration of contacts between objects, foods, and hands, and the sequence of events before the hands, foods, or objects are inserted into the mouth. This article describes the process of refining a videotaping and video-translation methodology to capture micro-level activity time series (MLATS), in order to better quantify total exposure for young children as a result of their behavior during meal events and cross-contamination of foods and hands. These MLATS can be seen as detailed activity patterns that provide useful data, along with transfer coefficients and environmental concentration to estimate exposures.

Quantifying children's aggregate (dietary and residential) exposure and dose to permethrin: application and evaluation of EPA's probabilistic SHEDS-Multimedia model

Reliable, evaluated human exposure and dose models are important for understanding the health risks from chemicals. A case study focusing on permethrin was conducted because of this insecticide's widespread use and potential health effects. SHEDS-Multimedia was applied to estimate US population permethrin exposures for 3- to 5-year-old children from residential, dietary, and combined exposure routes, using available dietary consumption data, food residue data, residential concentrations, and exposure factors. Sensitivity and uncertainty analyses were conducted to identify key factors, pathways, and research needs. Model evaluation was conducted using duplicate diet data and biomonitoring data from multiple field studies, and comparison to other models. Key exposure variables were consumption of spinach, lettuce, and cabbage; surface-to-skin transfer efficiency; hand mouthing frequency; fraction of hand mouthed; saliva removal efficiency; fraction of house treated; and usage frequency. For children in households using residential permethrin, the non-dietary exposure route was most important, and when all households were included, dietary exposure dominated. SHEDS-Multimedia model estimates compared well to real-world measurements data; this exposure assessment tool can enhance human health risk assessments and inform children's health research. The case study provides insights into children's aggregate exposures to permethrin and lays the foundation for a future cumulative pyrethroid pesticides risk assessment.

Statement on the ANSES reports on bisphenol A

Statement on the ANSES reports on bisphenol A