Human dermal exposure to galaxolide from personal care products

Musks are synthetic fragrances applied on personal care and household products as fixatives, by retarding the release of other fragrances with higher volatility. Galaxolide is the most used polycyclic musk since the 90th decade, and it has been detected in several environmental and biological matrices, particularly in human tissues and fluids. For exposure assessment purposes, large‐monitoring data need to be obtained and rapid but reliable analytical techniques are requested. The main objective of this study is to develop and validate a new and fast analytical methodology to quantify galaxolide in personal care products and to apply this method to real matrices like skin care products (creams and lotions), shower products (soap bar), hair care products (shampoo and hair conditioner) and oral care products (toothpaste), to evaluate the human dermal exposure risk. A dispersive solid‐phase extraction is proposed, using QuEChERS methodology, followed by HPLC with fluorescence detection. Some extraction parameters were studied, like the ratio of sample/solvent amounts, the homogenization time, the salt addition effect and the used sorbents. The validation parameters of the developed method were the following: a linearity range of 0.005–1.002 mg kg^?1 sample, a limit of detection of 0.001 mg kg^?1 sample, repeatability between 0.7% and 11.3% (variation coefficient of six standard injections), an intermediate precision of 2.5% (variation coefficient of six independent analysis of the same sample), mean recoveries ranging from 65% (soap bar) to 95% (body cream) and 3% of global uncertainty in most of the working range. The time of analysis, including the extraction steps, is 60 min, allowing a throughput of 4 samples h^?1. Galaxolide was detected in all of the seven analysed products in concentrations ranging from 0.04 ± 0.01 mg kg^?1 sample (toothpaste) to 280.78 ± 8.19 mg kg^?1 sample (perfumed body cream), which may correspond to a significant estimated daily human dermal exposure of 904 μg day^?1.     

Urinary PAH metabolites as biomarkers of exposure in aquatic environments

While immunoassays have been extensively applied to evaluate environmental contamination, to date they have rarely been used for the analysis of biological fluids outside of human medicine. These media are important because pollutants such as polycyclic aromatic hydrocarbons (PAHs) and their metabolites become concentrated in tissues, body fluids, and excreta, thereby offering a measure of exposure to biologically available contaminants. Such analyses also provide a nondestructive tool for monitoring exposure. Crabs (Carcinus maenas) were exposed to phenanthrene and pyrene (separately) at concentrations ranging from 0 to 200 microg L(-1). After 48 h, urine samples were taken and analyzed by immunoassay and UV-fluorescence spectrophotometry. Urinary levels (calibrated against hydroxylated metabolites) proved to be dose dependent for both compounds, and good agreementwas demonstrated between the immunoassay and the fluorescence techniques. The cross reactivity of the immunochemical technique (ELISA) for pyrene and hydroxy-metabolites was lower than for phenanthrene. HPLC analyses demonstrated that urine from the crabs exposed to pyrene contained mainly conjugate PAH metabolites whose concentrations (the sum of the four main pyrene metabolites/conjugates) showed very good agreement with the ELISA (r2 > 0.94) and fluorescence (r2 > 0.91) data. Environmental samples were also analyzed by ELISA and UV-fluorescence, and both techniques detected PAH (mainly petrogenic) contamination in the urine samples from a polluted harbor. These data demonstrate the potential of urine analyses by ELISA and UV-fluorescence to measure exposure of crabs to PAH.     

Levels and sources of personal inhalation exposure to volatile organic compounds

Personal exposures to VOCs of 12 urban dwellers were measured directly via personal monitoring and indirectly via static monitoring combined with personal activity diaries. Over 5-10 days, day-to-day variations in personal exposures of individuals were substantial, with statistically significant (p<0.05) deviation from the normal distribution observed for daily exposures to one or more VOCs for several subjects. Daytime concentrations generally exceeded night time, with day:night mean concentration ratios for each sampling day >1 for most VOCs, with the maximum (3.85) occurring for 1,3-butadiene. Exposure in the home contributed 50-80% of overall individual exposure to 1,3-butadiene and benzene. For most VOCs, while absolute values of direct and indirect exposure estimates were significantly different (p<0.05), linear regression of direct and indirect exposure estimates revealed statistically significant correlation (p<0.01), confirming previous observations that indirect monitoring can provide satisfactory estimates of personal inhalation exposure to VOCs. ETS, the use of vehicles, and heating (but not cooking) all made appreciable contributions to personal exposure to all target VOCs.     

Plenary lecture: innovative modeling approaches applicable to risk assessments

Proper identification of safe and unsafe food at the processing plant is important for maximizing the public health benefit of food by ensuring both its consumption and safety. Risk assessment is a holistic approach to food safety that consists of four steps: 1) hazard identification; 2) exposure assessment; 3) hazard characterization; and 4) risk characterization. Risk assessments are modeled by mapping the risk pathway as a series of unit operations and associated pathogen events and then using probability distributions and a random sampling method to simulate the rare, random, variable and uncertain nature of pathogen events in the risk pathway. To model pathogen events, a rare event modeling approach is used that links a discrete distribution for incidence of the pathogen event with a continuous distribution for extent of the pathogen event. When applied to risk assessment, rare event modeling leads to the conclusion that the most highly contaminated food at the processing plant does not necessarily pose the highest risk to public health because of differences in post-processing risk factors among distribution channels and consumer populations. Predictive microbiology models for individual pathogen events can be integrated with risk assessment models using the rare event modeling method.     

Development of a passive sampler to measure personal exposure to gaseous PAHs in community settings

A sensitive, simple, and cost-effective passive sampling methodology was developed to quantify personal exposure to gaseous polycyclic aromatic hydrocarbons (PAHs). A Fan-Lioy passive PAH sampler (FL-PPS) is constructed from 320 sections of 1-cm long SPB-5 GC columns (0.75-mm i.d. and 7-microm film thickness), similar to a mini-honeycomb denuder. Given the unique feature of the GC column stationary phase, gaseous PAHs are collected on the inner surfaces of the columns by molecular diffusion and thermally desorbed to GC/MS for analysis. The sampling rates of FL-PPS were determined in the laboratory using a controlled test atmosphere containing eight PAHs for a range of face velocity, temperature, relative humidity, PAH concentration, and sampling duration. The sampling rate (mean, %RSD, cm3/min) was 26.7 (21%) for acenaphthylene, 37.6 (25%) for acenaphthene, 56.2 (13%) for fluorene, 49.1 (25%) for phenanthrene, 62.7 (22%) for anthracene, 65.4 (24%) for fluoranthene, and 64.4 (18%) for pyrene over a sampling duration of 8-48 h. The sampling rate for naphthalene was approximately 14.1 (12%) cm3/min over a sampling period of 8 h but decreased along with an increase of sampling time. The effects of temperature, humidity, face velocity, and PAH concentration on the sampling rate were not significant for all the compounds tested. A reasonable agreement (<30%) was obtained for most compounds measured by FL-PPS and a conventional active PAH sampling method colocated side-by-side in the field, but a sampling time of 24 h or longer was required for detection of less abundant PAHs in community settings.     

Comparative proteomic approaches to analysis of litchi pulp senescence after harvest

Litchi fruit (Litchi chinensis Sonn.) is highly perishable after harvest. The shelf life is only 4–6 days under ambient temperature storage conditions, which has restricted the development of the litchi industry to a considerable extent. To investigate the molecular mechanisms of litchi fruit senescence, comparative proteomic analysis was carried out on litchi pulp. After two-dimensional gel electrophoresis (2-DE), 64 spots were significantly differentially expressed, 61 of which were successfully identified using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC–ESI–MS/MS). All of the identified proteins were classified according to biological process, molecular function, and cellular component using Blast2GO. Results showed that those proteins were mainly involved in signal transduction, cell wall metabolism, primary and secondary metabolism, energy metabolism. Specifically, many up-regulated proteins were involved in auxin/ethylene regulation, which suggested that auxin and ethylene might cooperate to regulate litchi pulp senescence. Histone deacetylase and DNA methyltransferase might involve the down-regulation of proteins related to reactive oxygen species (ROS) scavenging, glycolysis, tricarboxylic acid cycle, and ATP synthesis in litchi senescence. A higher proportion of differentially expressed proteins were up-regulated and these were involved in a range of processes including cell wall organization or biogenesis, anaerobic respiration, protein degradation, lipid degradation. All of those proteins might accelerate fruit softening, deterioration and senescence. This study is the first to carry out proteomic analysis of the regulation of litchi fruit senescence.     

Simulated consumer exposure to propellant HCFC 22 (chlorodifluoromethane) in aerosol personal products

The potential human exposure to the aerosol propellant HCFC 22 (chlorodifluoromethane) arising from its use in personal products has been assessed. HCFC 22 concentrations were measured in the 'breathing zone' of an experimental manikin and an 'accompanying child' designed to simulate human use of hairsprays, body sprays and antiperspirants in a closed room. Results were expressed as the 10-min time-weighted average concentration in the air (TWA 10) and as the peak concentration in the 'breathing zone' of the 'user'.
Following a 10-s use of hairspray containing approximately 20–40% HCFC 22, TWA10 values for an adult user and child were 64–116 ppm and 44–100 ppm, respectively. Use of an aerosol body spray containing 20–65% HCFC 22 for 5–20 s gave rise to TWA10 values of 32–411 ppm for an adult user and 20–395 ppm for a child. A 4-s use of an antiperspirant containing approximately 20–40% HCFC 22 sprayed at a distance of 10–30 cm from the breathing zone of the adult user generated TWA 10 values in the range of 14–34 ppm for both the adult user and child. Opening the door of the room prior to hairspray and antiperspirant spraying slightly reduced these TWA 10 values. The peak values recorded in these studies for the adult user were 208 ppm for hairspray, 1415 ppm for body sprays and 82 ppm for antiperspirants.     

Novel active personal nanoparticle sampler for the exposure assessment of nanoparticles in workplaces

A novel active personal nanoparticle sampler (PENS), which enables the collection of both respirable particulate mass (RPM) and nanoparticles (NPs) simultaneously, was developed to meet the critical demand for personal sampling of engineered nanomaterials (ENMs) in workplaces. The PENS consists of a respirable cyclone and a micro-orifice impactor with the cutoff aerodynamic diameter (d(pa50)) of 4 μm and 100 nm, respectively. The micro-orifice impactor has a fixed micro-orifice plate (137 nozzles of 55 μm in the inner diameter) and a rotating, silicone oil-coated Teflon filter substrate at 1 rpm to achieve a uniform particle deposition and avoid solid particle bounce. A final filter is used after the impactor to collect the NPs. Calibration results show that the d(pa50) of the respirable cyclone and the micro-orifice impactor are 3.92 ± 0.22 μm and 101.4 ± 0.1 nm, respectively. The d(pa50) at the loaded micro-Al(2)O(3) mass of 0.36-3.18 mg is shifted to 102.9-101.2 nm, respectively, while it is shifted to 98.9-97.8 nm at the loaded nano-TiO(2) mass of 0.92-1.78 mg, respectively. That is, the shift of d(pa50) due to solid particle loading is small if the PENS is not overloaded. Both NPs and RPM concentrations were found to agree well with those of the IOSH respirable cyclone and MOUDI. By using the present PENS, the collected samples can be further analyzed for chemical species concentrations besides gravimetric analysis to determine the actual exposure concentrations of ENMs in both RPM and NPs fractions in workplaces, which are often influenced by the background or incident pollution sources.     

Utilize of mathematical modeling methods for human health risk assessment from exposure to food contaminants

The present review reports on the mathematical methods and statistical techniques available for human health risk assessment from exposure to food contaminants. A framework is established for the usage of these methods instead of traditional toxicological techniques. Regarding to each method applicability, strengths, limitations and weaknesses are described.     

Black carbon-inclusive modeling approaches for estimating the aquatic fate of dibenzo-p-dioxins and dibenzofurans

A novel black carbon (BC) inclusive modeling tool is applied to estimate the distribution and long-term fate of dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the Norwegian Grenland Fjords. Three versions of the model were developed in which sediment-water partitioning was described using (i) an amorphous organic carbon (AOC) partitioning sorption model without BC sorption, (ii) a combined AOC and BC sorption model based on the Freundlich isotherm, and (iii) a combined BC-AOC model based on the Langmuir isotherm. The predictive ability of the three different models was evaluated for 17 PCDD/Fs by comparison of model predictions with observed organic carbon normalized sediment-water partition coefficients (K(TOC)) and with measured concentrations. All three versions of the model were able to predict concentrations that were in reasonable agreement with measured particulate concentrations (i.e., within a factor of 4 of median values). Estimated particulate concentrations were less sensitive to the model choice because the majority of the mass of these hydrophobic chemicals is associated with particulates regardless. However, for estimation of K(TOC) or dissolved water concentrations, both versions of the combined AOC and BC sorption models provided greatly improved estimates compared to the AOC-only model.     

Simple intake and pharmacokinetic modeling to characterize exposure of Americans to perfluoroctanoic acid, PFOA

Models for assessing intakes of perfluorooctanoic acid, PFOA, are described and applied. One model is based on exposure media concentrations and contact rates. This model is applied to general population exposures for adults and 2-year old children. The other model is a simple one-compartment, first-order pharmacokinetic (PK) model. Parameters for this model include a rate of elimination of PFOA and a blood volume of distribution. The model was applied to data from the National Health and Nutritional Examination Survey, NHANES, to backcalculate intakes. The central tendency intake estimate for adults and children based on exposure media concentrations and contact rates were 70 and 26 ng/day, respectively. The central tendency adult intake derived from NHANES data was 56 and 37 ng/day for males and females, respectively. Variability and uncertainty discussions regarding the intake modeling focus on lack of data on direct exposure to PFOA used in consumer products, precursor compounds, and food. Discussions regarding PK modeling focus on the range of blood measurements in NHANES, the appropriateness of the simple PK model, and the uncertainties associated with model parameters. Using the PK model, the 10th and 95th percentile long-term average adult intakes of PFOA are 15 and 130 ng/day.     

Improved approaches for modeling the sorption of phenanthrene by a range of plant species

Equilibrium sorption of phenanthrene and its relationship with plant lipid contents were investigated using roots and shoots of alfalfa, ryegrass, tomato, potato, carrot, cucumber, zucchini, and pumpkin. Lipid extractions using chloroform and hexane were compared, and the influence of dechlorophyllization on lipid determinations was evaluated. The sorption isotherms were close to linear (R2 > 0.923, P < 0.05) and the plant-water partition coefficients (K(pl)) of phenanthrene obtained from the isotherms exhibited significant and positive correlations with plantlipid contents (R2 > 0.664, P < 0.05). The correlations were more significant (R2 > 0.906, P < 0.001) when dechlorophyllization was included in the lipid extraction. The measured sorption was higher than that estimated using the octanol-water partition coefficient (K(ow)) but was very close to the estimate using the triolein-water partition coefficient (K(tw)). This study leads us to conclude that dechlorophyllization is necessary for plant lipid determination and that K(tw) is more accurate as a substitute for the lipid-water partition coefficient (K(lip)) than K(ow). These novel approaches may provide substantial improvements in the application of partition-limited models for the estimation of plant uptake of organic contaminants.     

Calculation of the dietary exposure of Chinese consumers to acephate residues using deterministic and probabilistic approaches

This paper compares the exposure for the Chinese populations and sub-groups to acephate, a widely applied organophosphorus pesticide, using deterministic and probabilistic approaches. Acephate residue data were obtained from the national food contamination monitoring program 2001-2006, collected by multi-stage stratified sampling and with a detection rate of 3.3%. Food consumption data were gathered from the national diet and nutrition survey conducted in 2002 over three consecutive days by the 24-h recall method, and included 22,563 families or 65,886 consumers aged 2-100 years. For point estimate, it was evident that exposures were higher than the acute reference dose (ARfD) in many cases. For the probabilistic approach, the P99.9 exposures for the general population and children accounted for 11.88 and 24.15% of the ARfD, respectively, in acute intake calculations and 52.86 and 68.75%, respectively, of the acceptable daily intake (ADI) in chronic intake calculations. The exposure level of rural people was higher than urban dwellers, and vegetables contributed most to acephate intake.     

Calculation of the dietary exposure of Chinese consumers to acephate residues using deterministic and probabilistic approaches

This paper compares the exposure for the Chinese populations and sub-groups to acephate, a widely applied organophosphorus pesticide, using deterministic and probabilistic approaches. Acephate residue data were obtained from the national food contamination monitoring program 2001–2006, collected by multi-stage stratified sampling and with a detection rate of 3.3%. Food consumption data were gathered from the national diet and nutrition survey conducted in 2002 over three consecutive days by the 24-h recall method, and included 22,563 families or 65,886 consumers aged 2–100 years. For point estimate, it was evident that exposures were higher than the acute reference dose (ARfD) in many cases. For the probabilistic approach, the P99.9 exposures for the general population and children accounted for 11.88 and 24.15% of the ARfD, respectively, in acute intake calculations and 52.86 and 68.75%, respectively, of the acceptable daily intake (ADI) in chronic intake calculations. The exposure level of rural people was higher than urban dwellers, and vegetables contributed most to acephate intake.     

Validity of residential traffic intensity as an estimate of long-term personal exposure to traffic-related air pollution among adults

The validity of traffic intensity near the home as an estimate for the personal long-term exposure to traffic-related air pollution in an adult population was tested. Personal and near-home outdoor exposure to PM2.5, soot, NO, NO2, and NOx was monitored four to five times during 48 h periods in older adults. A group of 23 participants lived in high traffic intensity streets (>10000 vehicles/(24 h)), and 22 lived in low traffic intensity streets. The relation between average personal exposure and traffic intensity at the residential address was explored by taking indoor sources into account. Large differences in the measured outdoor concentrations between locations in high traffic and low traffic intensity streets were found for soot (68%), NO (127%), and NOx (35%). Differences were smaller for PM2.5 (14%) and NO2 (22%). Slightly elevated ratios were found for personal exposure to soot (1.15; 95% confidence interval (CI), 1.01-1.30)when comparing adults living in high traffic intensity streets with adults living in low traffic intensity streets. For NO, increased personal exposure (1.16) was seen for the same comparison, but this difference failed to reach statistical significance (CI, 0.80-1.66). Traffic intensity on the street of residence predicted personal exposure to soot but not to PM2.5 or nitrogen oxides. Traffic intensity may not correlate well to personal exposure and accordingly substantial misclassification of exposure may occur when traffic intensity is used as an exposure indicator in epidemiological studies. Time spent in traffic and spending time outdoors were associated with increased personal exposure of soot and PM2.5, but not NOx.     

Prediction of personal exposure to PM2.5 and carcinogenic polycyclic aromatic hydrocarbons by their concentrations in residential microenvironments

We measured exposure to fine particles (PM2.5) and polycyclic aromatic hydrocarbons (PAHs), including carcinogenic PAHs, in multiple locations for a diverse population of participants who resided in Shizuoka, Japan. In summer and winter 2002 we surveyed personal concentrations, those of four primary indoor microenvironments-living room, bedroom, kitchen (summer only), and workplace--and those outside the subjects' houses. Concentrations of PM2.5 and PAHs tended to be higher during winter. Median PM2.5 concentration was highest in living room samples during winter but in personal samples during summer. The median PAH concentrations normalized to the cancer potency equivalence factor of benzo[a]pyrene (BaP-TEQ) was highest in the bedroom during winter but outdoors in summer. Personal exposure level profiles differed markedly between smokers and nonsmokers. Personal exposures to BaP ([BaP]p) and BaP-TEQ ([BaP-TEQ]P) in nonsmokers were strongly correlated. Personal exposures of nonsmokers, as calculated from the corresponding time-weighted indoor and outdoor concentrations, were consistent with measured levels of BaP but not PM2.5. Personal exposure of nonsmokers to BaP, as calculated from the time-weighted living room, bedroom, and either workplace or outdoor concentrations, accounted for 92-107% of the measured levels of BaP-TEQ.     

Proceedings of the workshop on food-consumption surveys in developing countries: general approaches to estimation of dietary exposure to contaminants

The initial steps in estimating dietary exposure to contaminants include gathering the necessary expertise, clarifying the intent and purpose of the work, selecting a dietary exposure model, and gathering available pertinent information. Expertise is generally needed in chemistry, agriculture, toxicology, statistics, nutritional epidemiology, and computer software development. The goal might be to determine the average exposure of a population to contaminants, to identify demographic groups within a population that are especially vulnerable to a contaminant, to evaluate the regulation of agricultural and food-manufacturing practices, or to determine compliance with standards for local and/or imported foods. Examples of dietary exposure models include the core food model, directed core food model, large database model, raw agricultural commodity (RAC) model, regional diet model, duplicate diet model, and total diet composite model. Each model has advantages and disadvantages and different costs and resource requirements. Consideration of the sources and flow of selected contaminants though the food supply may help identify the best exposure model to use. Pertinent information that may already be available includes analytical data on contaminants in foods or commodities, government regulations pertaining to the levels of contaminants in foods, food-consumption data, data on the average body weights of age-gender groups (to express exposure on a body weight basis), and biochemical measures of contaminants or their residues/metabolites. Collecting available information helps to clearly define what critical information is missing so that the planned research can be most effective. Careful documentation of decisions and assumptions allows for recalculating exposure estimates with the same model using different decisions and assumptions; documentation also allows others to understand what was done and how to use the resulting intake estimates properly. Clearly identifying the limitations of the exposure model may provide justification for additional resources to further refine and improve the model.     

中国地区干酪生物胺风险评估中膳食暴露评估模型的构建

基于对中国地区市售97份干酪样品获得的8种生物胺检测数据,以及2002年中国居民营养与健康状况调查报告中的膳食消费数据,采用Monte Carlo模拟和@Risk软件量化人群干酪生物胺膳食暴露量的变异度和不确定度,构建中国地区干酪生物胺风险评估中膳食暴露评估模型。按不同地区、性别和年龄段差异的人群,分析其干酪生物胺膳食暴露量分布的统计量和90%置信区间。评估结果显示,中国城市人群的干酪生物胺暴露量明显高于同年龄段的农村人群;且城市地区女性暴露量通常高于男性,而农村地区则相反。干酪生物胺膳食暴露概率评估方法相比点评估和简单分布评估方法,能够定量评估结果的变异度和不确定度,评估更为准确。