Improving Emergency Airway Knowledge and Self-Efficacy Levels of Outpatient Gastroenterology Staff via Implementation of Online Education and In Situ Simulation.

Twenty percent of all ambulatory surgery cases utilizing monitored anesthesia care and sedation report at least one perioperative respiratory complication such as bronchospasm, hypoxia, laryngospasm, or aspiration (). However, the national Standards of Practice for both surgical technicians and ambulatory care nurses do not mandate emergency airway education beyond cardiopulmonary resuscitation and Basic Life Support training. A local outpatient gastroenterology clinic noticed the gap in education, and the anesthesia team decided to implement an evidence-based dual-factorial quality improvement project utilizing online education and in situ simulation. First, registered nurses and procedural technologists completed a test to assess their baseline knowledge and airway emergency performance self-efficacy levels. Then an online module was distributed that included information on the 3 most common anesthesia airway emergencies in the outpatient setting: laryngospasm, aspiration, and obstruction with resultant hypoxemia. Next, participants completed an in situ simulation of the 3 airway emergencies using low-fidelity mannequins. A post-education assessment was distributed after completion of the simulation training and again at 6 weeks and 3 months post-implementation. The data collected showed a statistically significant increase in both knowledge scores and levels of self-efficacy at 6 weeks and 3 months posteducation (p < .001).

Computational Exposure Science: An Emerging Discipline to Support 21st-Century Risk Assessment.

BACKGROUND: Computational exposure science represents a frontier of environmental science that is emerging and quickly evolving. OBJECTIVES: In this commentary, we define this burgeoning discipline, describe a framework for implementation, and review some key ongoing research elements that are advancing the science with respect to exposure to chemicals in consumer products. DISCUSSION: The fundamental elements of computational exposure science include the development of reliable, computationally efficient predictive exposure models; the identification, acquisition, and application of data to support and evaluate these models; and generation of improved methods for extrapolating across chemicals. We describe our efforts in each of these areas and provide examples that demonstrate both progress and potential. CONCLUSIONS: Computational exposure science, linked with comparable efforts in toxicology, is ushering in a new era of risk assessment that greatly expands our ability to evaluate chemical safety and sustainability and to protect public health. CITATION: Egeghy PP, Sheldon LS, Isaacs KK, Özkaynak H, Goldsmith M-R, Wambaugh JF, Judson RS, Buckley TJ. 2016. Computational exposure science: an emerging discipline to support 21st-century risk assessment. Environ Health Perspect 124:697-702; http://dx.doi.org/10.1289/ehp.1509748.

A biomonitoring framework to support exposure and risk assessments.

BACKGROUND: Biomonitoring is used in exposure and risk assessments to reduce uncertainties along the source-to-outcome continuum. Specifically, biomarkers can help identify exposure sources, routes, and distributions, and reflect kinetic and dynamic processes following exposure events. A variety of computational models now utilize biomarkers to better understand exposures at the population, individual, and sub-individual (target) levels. However, guidance is needed to clarify biomonitoring use given available measurements and models. OBJECTIVE: This article presents a biomonitoring research framework designed to improve biomarker use and interpretation in support of exposure and risk assessments. DISCUSSION: The biomonitoring research framework is based on a modified source-to-outcome continuum. Five tiers of biomonitoring analyses are included in the framework, beginning with simple cross-sectional and longitudinal analyses, and ending with complex analyses using various empirical and mechanistic models. Measurements and model requirements of each tier are given, as well as considerations to enhance analyses. Simple theoretical examples are also given to demonstrate applications of the framework for observational exposure studies. CONCLUSION: This biomonitoring framework can be used as a guide for interpreting existing biomarker data, designing new studies to answer specific exposure- and risk-based questions, and integrating knowledge across scientific disciplines to better address human health risks.

Review of pesticide urinary biomarker measurements from selected US EPA children's observational exposure studies.

Children are exposed to a wide variety of pesticides originating from both outdoor and indoor sources. Several studies were conducted or funded by the EPA over the past decade to investigate children's exposure to organophosphate and pyrethroid pesticides and the factors that impact their exposures. Urinary metabolite concentration measurements from these studies are consolidated here to identify trends, spatial and temporal patterns, and areas where further research is required. Namely, concentrations of the metabolites of chlorpyrifos (3,5,6-trichloro-2-pyridinol or TCPy), diazinon (2-isopropyl-6-methyl-4-pyrimidinol or IMP), and permethrin (3-phenoxybenzoic acid or 3-PBA) are presented. Information on the kinetic parameters describing absorption and elimination in humans is also presented to aid in interpretation. Metabolite concentrations varied more dramatically across studies for 3-PBA and IMP than for TCPy, with TCPy concentrations about an order of magnitude higher than the 3-PBA concentrations. Temporal variability was high for all metabolites with urinary 3-PBA concentrations slightly more consistent over time than the TCPy concentrations. Urinary biomarker levels provided only limited evidence of applications. The observed relationships between urinary metabolite levels and estimates of pesticide intake may be affected by differences in the contribution of each exposure route to total intake, which may vary with exposure intensity and across individuals.

Assessing the quantitative relationships between preschool children's exposures to bisphenol A by route and urinary biomonitoring.

Limited published information exists on young children's exposures to bisphenol A (BPA) in the United States using urinary biomonitoring. In a previous project, we quantified the aggregate exposures of 257 preschool children to BPA in environmental and personal media over 48-h periods in 2000-2001 at homes and daycares in North Carolina and Ohio. In the present study for 81 Ohio preschool children ages 23-64 months, we quantified the children's urinary total BPA (free and conjugated) concentrations over these same 48-h periods in 2001. Then, we examined the quantitative relationships between the children's intakes doses of BPA through the dietary ingestion, nondietary ingestion, and inhalation routes and their excreted amounts of urinary BPA. BPA was detected in 100% of the urine samples. The estimated median intake doses of BPA for these 81 children were 109 ng/kg/day (dietary ingestion), 0.06 ng/kg/day (nondietary ingestion), and 0.27 ng/kg/day (inhalation); their estimated median excreted amount of urinary BPA was 114 ng/kg/day. Our multivariable regression model showed that dietary intake of BPA (p = 0.04) and creatinine concentration (p = 0.004) were significant predictors of urinary BPA excretion, collectively explaining 17% of the variability in excretion. Dietary ingestion of BPA accounted for >95% of the children's excreted amounts of urinary BPA.

The reliability of using urinary biomarkers to estimate children's exposures to chlorpyrifos and diazinon.

A few studies have reported concurrent levels of chlorpyrifos (CPF) and diazinon (DZN) and their environmentally occurring metabolites, 3,5,6-trichloro-2-pyridinol (TCP) and 2-isopropyl-6-methyl-4-pyrimidinol (IMP), in food and in environmental media. This information raises questions regarding the reliability of using these same metabolites, TCP and IMP, as urinary biomarkers to quantitatively assess the everyday exposures of children to CPF and DZN, respectively. In this study, we quantified the distributions of CPF, DZN, TCP, and IMP in several environmental and personal media at the homes and day-care centers of 127 Ohio preschool children and identified the important sources and routes of their exposures. The children were exposed to concurrent levels of these four chemicals from several sources and routes at these locations. DZN and IMP were both detected above 50% in the air and dust samples. CPF and TCP were both detected in greater than 50% of the air, dust (solid), food, and hand wipe samples. TCP was detected in 100% of the urine samples. Results from our regression models showed that creatinine levels (<0.001), and dietary (P<0.001) and inhalation (P<0.10) doses of TCP were each significant predictors of urinary TCP, collectively explaining 27% of the urinary TCP variability. This information suggests that measurement of urinary TCP did not reliably allow quantitative estimation of the children's everyday environmental exposures to CPF.

Adapting concepts from systems biology to develop systems exposure event networks for exposure science research.

Systems exposure science has emerged from the traditional environmental exposure assessment framework and incorporates new concepts that link sources of human exposure to internal dose and metabolic processes. Because many human environmental studies are designed for retrospective exposure evaluations they often do not provide practical toxicological outcome parameters. Our goal was to examine concepts from systems biology research and adapt them to a network approach that maps forward to a perturbation event using two hypothetical examples. The article proposes that environmental exposure studies should not only retrospectively document exposure levels, but also measure biological parameters that can be used to inform relevant systemic changes.

Organophosphorus and pyrethroid insecticide urinary metabolite concentrations in young children living in a southeastern United States city.

Pesticide metabolites are routinely measured in the urine of children in the United States. Although the sources of these metabolites are believed to include residues in food from agricultural applications and residues from applications in everyday environments (e.g., homes), few studies have been able to demonstrate an association between indoor residential pesticide applications and pesticide metabolite concentrations. To better quantify the effects of potential risk factors related to demographics, household characteristics, occupation, and pesticide use practices on urinary biomarker levels, we performed a study in a city (Jacksonville, Florida) previously determined to have elevated rates of pesticide use. We enrolled a convenience sample of 203 children ranging in age from 4 to 6 years; their caregivers completed a questionnaire and the children provided a urine sample, which was analyzed for a series of organophosphorus and pyrethroid insecticide metabolites. The questionnaire responses substantiated much higher pesticide use for the study participants as compared to other studies. Urinary metabolite concentrations were approximately an order of magnitude higher than concentrations reported for young children in other studies. Few statistically significant differences (at the p<0.05 level) were observed, however, several trends are worth noting. In general, mean urinary pesticide metabolite concentrations were higher for males, Caucasians, and those children living in homes with an indoor pesticide application occurring within the past four weeks. Comparing the urinary pesticide metabolite concentrations in this study to those reported in the NHANES and GerES studies showed that the children living in Jacksonville had substantially higher pyrethroid pesticide exposures than the general populations of the United States and Germany. Further research is needed in communities where routine pesticide use has been documented to obtain information on the most important routes and pathways of exposure and to develop the most effective strategies for reducing pesticide exposures for children.

Urinary biomarker, dermal, and air measurement results for 2,4-D and chlorpyrifos farm applicators in the Agricultural Health Study.

A subset of private pesticide applicators in the Agricultural Health Study (AHS) epidemiological cohort was monitored around the time of their agricultural use of 2,4-dichlorophenoxyacetic acid (2,4-D) and O,O-diethyl-O-3,5,6-trichloro-2-pyridyl phosphorothioate (chlorpyrifos) to assess exposure levels and potential determinants of exposure. Measurements included pre- and post-application urine samples, and patch, hand wipe, and personal air samples. Boom spray or hand spray application methods were used by applicators for 2,4-D products. Chlorpyrifos products were applied using spray applications and in-furrow application of granular products. Geometric mean (GM) values for 69 2,4-D applicators were 7.8 and 25 microg/l in pre- and post-application urine, respectively (P<0.05 for difference); 0.39 mg for estimated hand loading; 2.9 mg for estimated body loading; and 0.37 microg/m(3) for concentration in personal air. Significant correlations were found between all media for 2,4-D. GM values for 17 chlorpyrifos applicators were 11 microg/l in both pre- and post-application urine for the 3,5,6-trichloro-2-pyridinol metabolite, 0.28 mg for body loading, and 0.49 microg/m(3) for air concentration. Only 53% of the chlorpyrifos applicators had measurable hand loading results; their median hand loading being 0.02 mg. Factors associated with differences in 2,4-D measurements included application method and glove use, and, for hand spray applicators, use of adjuvants, equipment repair, duration of use, and contact with treated vegetation. Spray applications of liquid chlorpyrifos products were associated with higher measurements than in-furrow granular product applications. This study provides information on exposures and possible exposure determinants for several application methods commonly used by farmers in the cohort and will provide information to assess and refine exposure classification in the AHS. Results may also be of use in pesticide safety education for reducing exposures to pesticide applicators.

Assessment of a pesticide exposure intensity algorithm in the agricultural health study.

The accuracy of the exposure assessment is a critical factor in epidemiological investigations of pesticide exposures and health in agricultural populations. However, few studies have been conducted to evaluate questionnaire-based exposure metrics. The Agricultural Health Study (AHS) is a prospective cohort study of pesticide applicators who provided detailed questionnaire information on their use of specific pesticides. A field study was conducted for a subset of the applicators enrolled in the AHS to assess a pesticide exposure algorithm through comparison of algorithm intensity scores with measured exposures. Pre- and post-application urinary biomarker measurements were made for 2,4-D (n=69) and chlorpyrifos (n=17) applicators. Dermal patch, hand wipe, and personal air samples were also collected. Intensity scores were calculated using information from technician observations and an interviewer-administered questionnaire. Correlations between observer and questionnaire intensity scores were high (Spearman's r=0.92 and 0.84 for 2,4-D and chlorpyrifos, respectively). Intensity scores from questionnaires for individual applications were significantly correlated with post-application urinary concentrations for both 2,4-D (r=0.42, P<0.001) and chlorpyrifos (r=0.53, P=0.035) applicators. Significant correlations were also found between intensity scores and estimated hand loading, estimated body loading, and air concentrations for 2,4-D applicators (r-values 0.28-0.50, P-values<0.025). Correlations between intensity scores and dermal and air measures were generally lower for chlorpyrifos applicators using granular products. A linear regression model indicated that the algorithm factors for individual applications explained 24% of the variability in post-application urinary 2,4-D concentration, which increased to 60% when the pre-application urine concentration was included. The results of the measurements support the use of the algorithm for estimating questionnaire-based exposure intensities in the AHS for liquid pesticide products. Refinement of the algorithm may be possible using the results from this and other measurement studies.

Exposure as part of a systems approach for assessing risk.

BACKGROUND: The U.S. Environmental Protection Agency is facing large challenges in managing environmental chemicals with increasingly complex requirements for assessing risk that push the limits of our current approaches. To address some of these challenges, the National Research Council (NRC) developed a new vision for toxicity testing. Although the report focused only on toxicity testing, it recognized that exposure science will play a crucial role in a new risk-based framework. OBJECTIVE: In this commentary we expand on the important role of exposure science in a fully integrated system for risk assessment. We also elaborate on the exposure research needed to achieve this vision. DISCUSSION: Exposure science, when applied in an integrated systems approach for risk assessment, can be used to inform and prioritize toxicity testing, describe risks, and verify the outcomes of testing. Exposure research in several areas will be needed to achieve the NRC vision. For example, models are needed to screen chemicals based on exposure. Exposure, dose-response, and biological pathway models must be developed and linked. Advanced computational approaches are required for dose reconstruction. Monitoring methods are needed that easily measure exposure, internal dose, susceptibility, and biological outcome. Finally, population monitoring studies are needed to interpret toxicity test results in terms of real-world risk. CONCLUSION: This commentary is a call for the exposure community to step up to the challenge by developing a predictive science with the knowledge and tools for moving into the 21st century.

The design and field implementation of the Detroit Exposure and Aerosol Research Study.

The US Environmental Protection Agency recently conducted the Detroit Exposure and Aerosol Research Study (DEARS). The study began in 2004 and involved community, residential, and personal-based measurements of air pollutants targeting 120 participants and their residences. The primary goal of the study was to evaluate and describe the relationship between air toxics, particulate matter (PM), PM constituents, and PM from specific sources measured at a central site monitor with those from the residential and personal locations. The impact of regional, local (point and mobile), and personal sources on pollutant concentrations and the role of physical and human factors that might influence these concentrations were investigated. A combination of active and passive sampling methodologies were employed in the collection of PM mass, criteria gases, semivolatile organics, and volatile organic compound air pollutants among others. Monitoring was conducted in six selected neighborhoods along with one community site using a repeated measure design. Households from each of the selected communities were monitored for 5 consecutive days in the winter and again in the summer. Household, participant and a variety of other surveys were utilized to better understand human and household factors that might affect the impact of ambient-based pollution sources upon personal and residential locations. A randomized recruitment strategy was successful in enrolling nearly 140 participants over the course of the study. Over 36,000 daily-based environmental data points or records were ultimately collected. This paper fully describes the design of the DEARS and the approach used to implement this field monitoring study and reports select preliminary findings.

Adult and children's exposure to 2,4-D from multiple sources and pathways.

In this study, we investigated the 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide exposures of 135 preschool-aged children and their adult caregivers at 135 homes in North Carolina (NC) and Ohio (OH). Participants were randomly recruited from six NC and six OH counties. Monitoring was performed over a 48-h period at the participants' homes. Environmental samples included soil, outdoor air, indoor air, and carpet dust. Personal samples collected by the adult caregivers concerning themselves and their children consisted of solid food, liquid food, hand wipe, and spot urine samples. All samples were analyzed for 2,4-D (free acid form) by gas chromatography/mass spectrometry. 2,4-D was detected in all types of environmental samples but most often in carpet dust samples, with detection frequencies of 83% and 98% in NC and OH, respectively. The median level of 2,4-D in the carpet dust samples was about three times higher in OH homes compared to NC homes (156 vs. 47.5 ng/g, P<0.0002). For personal samples, 2,4-D was more frequently detected in the hand wipe samples from OH participants (>48%) than from NC participants (<9%). Hand wipe levels at the 95th percentile were about five times higher for OH children (0.1 ng/cm(2)) and adults (0.03 ng/cm(2)) than for the NC children (0.02 ng/cm(2)) and adults (<0.005 ng/cm(2)). 2,4-D was detected in more than 85% of the child and adult urine samples in both states. The median urinary 2,4-D concentration was more than twice as high for OH children compared to NC children (1.2 vs. 0.5 ng/ml, P<0.0001); however, the median concentration was identical at 0.7 ng/ml for both NC and OH adults. The intraclass correlation coefficient of reliability for an individual's urinary 2,4-D measurements, estimated from the unadjusted (0.31-0.62) and specific gravity-adjusted (0.37-0.73) values, were somewhat low for each group in this study. The variability in urinary 2,4-D measurements over the 48-h period for both children and adults in NC and OH suggests that several spot samples were needed to adequately assess these participants' exposures to 2,4-D in residential settings. Results from this study showed that children and their adult caregivers in NC and OH were likely exposed to 2,4-D through several pathways at their homes. In addition, our findings suggest that the OH children might have been exposed to higher levels of 2,4-D through the dermal and nondietary routes of exposure than the NC children and the NC and OH adults.

An observational study of 127 preschool children at their homes and daycare centers in Ohio: environmental pathways to cis- and trans-permethrin exposure.

The potential exposures of 127 preschool children to the pyrethroid insecticides, cis- and trans-permethrin, in their everyday environments were examined. Participants were recruited randomly from 127 homes and 16 daycare centers in six Ohio (OH) counties. Monitoring was performed over a 48-h period at the children's homes and/or daycare centers. Samples collected included soil, carpet dust, indoor air, outdoor air, diet, hand wipes, surface wipes, transferable residues, and urine. The environmental samples were analyzed for the cis and trans isomers of permethrin, and the urine samples were analyzed for the pyrethroid urinary metabolite, 3-phenoxybenzoic acid (3-PBA), by gas chromatography/mass spectrometry. The isomers were detected most often in the dust (100%) and hand wipe (>78%) samples collected at both homes and daycare centers. The median levels of cis-permethrin (470 and 1010 ng/g) were higher than the median levels of trans-permethrin (344 and 544 ng/g) in the dust samples at both the children's homes and daycare centers, respectively. In the children's hand wipe samples, the median levels of cis- and trans-permethrin were similar, ranging from 0.03 to 0.04 ng/cm(2), at both locations. The urinary metabolite 3-PBA was detected in 67% of the children's urine samples. The median urinary 3-PBA concentration for the children was 0.3 ng/mL, and the maximum value for one child was 33.8 ng/mL. The primary route of the children's exposure to the combined isomers was through dietary ingestion, followed by indirect ingestion. In addition, our calculated aggregate absorbed doses of permethrin accounted for about 60% of the excreted amounts of 3-PBA found in the children's urine. In conclusion, these children were potentially exposed to low levels of permethrin from several sources, and through several pathways and routes.

Pesticides and their metabolites in the homes and urine of farmworker children living in the Salinas Valley, CA.

In support of planning efforts for the National Children's Study, we conducted a study to test field methods for characterizing pesticide exposures to 20 farmworker children aged 5-27 months old living in the Salinas Valley of Monterey County, California. We tested methods for collecting house dust, indoor and outdoor air, dislodgeable residues from surfaces and toys, residues on clothing (sock and union suits), food, as well as spot and overnight diaper urine samples. We measured 29 common agricultural and home use pesticides in multiple exposure media samples. A subset of organophosphorus (OP), organochlorine (OC) and pyrethroid pesticides were measured in food. We also analyzed urine samples for OP pesticide metabolites. Finally, we administered four field-based exposure assessment instruments: a questionnaire; food diary; home inspection; and a self-administered child activity timeline. Pesticides were detected more frequently in house dust, surface wipes, and clothing than other media, with chlorpyrifos, diazinon, chlorthal-dimethyl, and cis- and trans-permethrin detected in 90% to 100% of samples. Levels of four of these five pesticides were positively correlated among the house dust, sock, and union suit samples (Spearman's rho=0.18-0.76). Pesticide loading on socks and union suits was higher for the group of 10 toddlers compared to the 10 younger crawling children. Several OP pesticides, as well as 4,4'-DDE, atrazine, and dieldrin were detected in the food samples. The child activity timeline, a novel, low-literacy instrument based on pictures, was successfully used by our participants. Future uses of these data include the development of pesticide exposure models and risk assessment.

An observational study of the potential exposures of preschool children to pentachlorophenol, bisphenol-A, and nonylphenol at home and daycare.

The Children's Total Exposure to Persistent Pesticides and Other Persistent Organic Pollutants (CTEPP) study investigated the potential exposures of 257 preschool children, ages 1 1/2-5 yr, and their primary adult caregivers to more than 50 anthropogenic chemicals. Field sampling took place in selected counties in North Carolina (NC) and Ohio (OH) in 2000-2001. Over a 48-h period in each child's daycare center and/or home, food, beverages, indoor air, outdoor air, house dust, soil, participants' hand surfaces and urine were sampled. Additional samples-transferable residues, food preparation surface wipes, and hard floor surface wipes-were collected in the approximately 13% of the homes that had pesticide applications within the 7 days prior to field sampling. Three phenols were among the measured chemicals: pentachlorophenol (PCP), bisphenol-A [2,2-bis(4-hydroxyphenyl)propane], and nonylphenol (4-n-nonylphenol). Nonylphenol (NP) was detected in less than 11% of the samples in any medium. Among samples that were collected at all participants' homes and daycare centers, PCP was detected in >50% of indoor air, outdoor air, house dust, and urine samples; bisphenol-A (BPA) was detected in >50% of indoor air, hand wipe, solid food, and liquid food samples. The concentrations of the phenols in the sampled media were measured, and the children's potential exposures and potential absorbed doses resulting from intake through the inhalation, dietary ingestion, and indirect ingestion routes of exposure were estimated. The children's potential exposures to PCP were predominantly through inhalation: 78% in NC and 90% in OH. In contrast, their potential exposures to BPA were predominantly through dietary ingestion: 99%, for children in both states. The children's estimated exposures to PCP, calculated from the amounts excreted in their urine, exceeded their estimated maximum potential intake, calculated from the multimedia PCP concentrations, by a factor greater than 10. This inconsistency for PCP highlights the need for further research on the environmental pathways and routes of PCP exposure, investigation of possible exposures to other compounds that could be metabolized to PCP, and on the human absorption, metabolism, and excretion of this phenol over time periods longer than 48 h.

The use of biomonitoring data in exposure and human health risk assessments.

Biomonitoring uses analytic methods that permit the accurate measurement of low levels of environmental chemicals in human tissues. However, depending on the intended use, biomonitoring, like all exposure tools, may not be a stand-alone exposure assessment tool for some of its environmental public health uses. Although biomonitoring data demonstrate that many environmental chemicals are absorbed in human tissues, uncertainty exists regarding if and at what concentrations many of these chemicals cause adverse health outcomes. Moreover, without exposure pathway information, it is difficult to relate biomonitoring results to sources and routes of exposure and develop effective health risk management strategies. In September 2004, the Health and Environmental Sciences Institute, U.S. Environmental Protection Agency, Centers for Disease Control and Prevention, Agency for Toxic Substances and Disease Registry, and International Council of Chemical Associations co-sponsored the International Biomonitoring Workshop, which explored the processes and information needed for placing biomonitoring data into perspective for risk assessment purposes, with special emphasis on integrating biomarker measurements of exposure, internal dose, and potential health outcome. Scientists from international governments, academia, and industry recommended criteria for applying biomonitoring data for various uses. Six case studies, which are part of this mini-monograph, were examined: inorganic arsenic, methyl eugenol, organophosphorus pesticides, perfluorooctanesulfonate, phthalates, and polybrominated diphenyl ethers. Based on the workshop and follow-up discussions, this overview article summarizes lessons learned, identifies data gaps, outlines research needs, and offers guidance for designing and conducting biomonitoring studies, as well as interpreting biomonitoring data in the context of risk assessment and risk management.

Strategic biomonitoring initiatives: moving the science forward.

Biomonitoring programs in the United States and Europe demonstrate the vast array of data that are publicly available for the evaluation of exposure trends, identification of susceptible populations, detection of emerging chemical risks, the conduct of epidemiology studies, and evaluation of risk reduction strategies. To cultivate international discussion on these issues, the ILSI Health and Environmental Sciences Institute convened a scientific session at its annual meeting in January 2006 on "Integration of Biomonitoring Exposure Data into the Risk Assessment Process." This Forum paper presents perspectives from session speakers on the biomonitoring activities of the Centers for Disease Control and Prevention, the U.S. Environmental Protection Agency, the National Research Council Committee on Human Biomonitoring for Environmental Toxicants, the German Commission on Human Biomonitoring, and the Health and Environmental Sciences Institute Biomonitoring Technical Committee. Speakers noted that better estimates of biological concentrations of substances in the tissues of human populations can be combined with other exposure indices, as well as epidemiological and toxicologic data, to improve risk estimates. With this type of combined data, the potential also exists to define exposure levels at which hazard and risk are of minimal concern. Limitations in interpreting biomonitoring data were discussed, including the need for different criteria for applying biomonitoring data for exposure assessment, risk assessment, risk management, or disease prevention purposes. As efforts and resources are expended to improve the ability to apply biomonitoring exposure data in the risk assessment process, it is equally important to communicate the significance of such data to the public.

Children's residential exposure to chlorpyrifos: application of CPPAES field measurements of chlorpyrifos and TCPy within MENTOR/SHEDS-Pesticides model.

The comprehensive individual field-measurements on non-dietary exposure collected in the Children's-Post-Pesticide-Application-Exposure-Study (CPPAES) were used within MENTOR/SHEDS-Pesticides, a physically based stochastic human exposure and dose model. In this application, however, the model was run deterministically. The MENTOR/SHEDS-Pesticides employed the CPPAES as input variables to simulate the exposure and the dose profiles for seven children over a 2-week post-application period following a routine residential and professional indoor crack-and-crevice chlorpyrifos application. The input variables were obtained from a personal activity diary, microenvironmental measurements and personal biomonitoring data obtained from CPPAES samples collected from the individual children and in their homes. Simulation results were compared with CPPAES field measured values obtained from the children's homes to assess the utility of the different microenvironmental data collected in CPPAES, i.e. indicator toys and wipe samplers to estimate aggregate exposures that can be result from one or more exposure pathways and routes. The final analyses of the database involved comparisons of the actual data obtained from the individual biomarker samples of a urinary metabolite of chlorpyrifos (TCPy) and the values predicted by MENTOR/SHEDS-Pesticides using the CPPAES-derived variables. Because duplicate diet samples were not part of the CPPAES study design, SHEDs-Pesticides simulated dose profiles did not account for the dietary route. The research provided more confidence in the types of data that can be used in the inhalation and dermal contact modules of MENTOR/SHEDS-Pesticides to predict the pesticide dose received by a child. It was determined that we still need additional understanding about: (1) the types of activities and durations of activities that result in non-dietary ingestion of pesticides and (2) the influence of dietary exposures on the levels of TCPy found in the urine.

Optimizing a dansylhydrazine (DNSH) based method for measuring airborne acrolein and other unsaturated carbonyls.

The Passive Aldehydes and Ketones Sampler (PAKS) method has been developed to measure airborne carbonyls (aldehydes and ketones) by derivatizing the carbonyls with dansylhydrazine (DNSH) on a solid sorbent. The method collection efficiencies are approximately 100% for most saturated carbonyls, but are significantly lower for unsaturated carbonyls. In this study, we examined the mechanisms of DNSH reactions with unsaturated carbonyls, focusing on acrolein. With a better understanding of these mechanisms, we modified the sampling substrate conditions and HPLC analysis conditions of the original PAKS method, resulting in substantially improved collection efficiencies for acrolein and crotonaldehyde. Evaluated under a variety of conditions (temperature, humidity, presence of ozone), the modified PAKS method had a collection efficiency of 99%+/- 5% for acrolein (N= 36) and 96%+/- 20% for crotonaldehyde (N= 6). The acrolein-DNSH derivative was stable within 9.6% of the initial amount, after 14 days of storage at 4 degrees C, on the collection medium; and stable within 2.8% of the initial amount, after 16 days of storage at room temperature, in extract.