Quantitative risk assessment of the aggregate dermal exposure to the sensitizing fragrance geraniol in personal care products and household cleaning agents.

PubMed

Nijkamp, M M; Bokkers, B G H; Bakker, M I; Ezendam, J; Delmaar, J E

2015-10-01

A quantitative risk assessment was performed to establish if consumers are at risk for being dermally sensitized by the fragrance geraniol. Aggregate dermal exposure to geraniol was estimated using the Probabilistic Aggregate Consumer Exposure Model, containing data on the use of personal care products and household cleaning agents. Consumer exposure to geraniol via personal care products appeared to be higher than via household cleaning agents. The hands were the body parts receiving the highest exposure to geraniol. Dermal sensitization studies were assessed to derive the point of departure needed for the estimation of the Acceptable Exposure Level (AEL). Two concentrations were derived, one based on human studies and the other from dose-response analysis of the available murine local lymph node assay data. The aggregate dermal exposure assessment resulted in body part specific median exposures up to 0.041 μg/cm(2) (highest exposure 102 μg/cm(2)) for hands. Comparing the exposure to the lowest AEL (55 μg/cm(2)), shows that a range of 0.02-0.86% of the population may have an aggregated exposure which exceeds the AEL. Furthermore, it is demonstrated that personal care products contribute more to the consumer's geraniol exposure compared to household cleaning agents. Copyright © 2015 Elsevier Inc. All rights reserved.

FEASIBILITY OF USING THE MACROACTIVITY APPROACH TO ASSESS CHILDREN'S DERMAL EXPOSURE TO PESTICIDES

EPA Science Inventory

Results derived from an initial assessment of critical exposure pathways for children indicate that dermal contact may result in high residential exposures to pesticides. However, data on children's exposures and activities are insufficient to support quantitative assessments ...

Unraveling the Relative Importance of Oral and Dermal Contaminant Exposure in Reptiles: Insights from Studies Using the Western Fence Lizard (Sceloporus occidentalis)

PubMed Central

Weir, Scott M.; Talent, Larry G.; Anderson, Todd A.; Salice, Christopher J.

2014-01-01

Despite widespread recognition of significant data deficiencies, reptiles remain a relatively understudied taxon in ecotoxicology. To conduct ecological risk assessments on reptiles frequently requires using surrogate taxa such as birds, but recent research suggests that reptiles have significantly different exposure profiles and toxicant sensitivity. We exposed western fence lizards, Sceloporus occidentalis, to the same quantities of three model chemicals via oral (gavage) and dermal (ventral skin application) exposure for either 24 or 48 hours. Three phthalate esters (di-methyl phthalate [DMP], di-iso-butyl phthalate [DIBP], and di-n-octyl phthalate [DNOP]) were chosen as model chemicals because they represent a gradient of lipophilicity but are otherwise structurally similar. Overall, the more lipophilic phthalates (DIBP and DNOP) were found to have higher concentrations in tissues than the less lipophilic DMP. Significant differences in tissue concentrations between DIBP and DNOP were tissue-dependent, suggesting that delivery to a site of action following exposure is not only a simple function of lipophilicity. In dermal treatments, DMP usually had fewer detections (except in ventral skin samples), suggesting that lipophilicity (log Kow>2) is a requirement for uptake across the skin. In general, tissue residues were greater in oral treatments than dermal treatments (significant in adipose and liver tissue), but differences were driven strongly by differences in DMP which did not appear to be absorbed well across skin. When differences in tissue residue concentrations between oral and dermal exposure did occur, the difference was not drastic. Taken together these results suggest that dermal exposure should be considered in risk assessments for reptilian receptors. Dermal exposure may be an especially important route for reptiles as their ectothermic physiology translates to lower energetic demands and dietary exposure compared to birds and mammals. PMID:24941063

Unraveling the relative importance of oral and dermal contaminant exposure in reptiles: insights from studies using the western fence lizard (Sceloporus occidentalis).

PubMed

Weir, Scott M; Talent, Larry G; Anderson, Todd A; Salice, Christopher J

2014-01-01

Despite widespread recognition of significant data deficiencies, reptiles remain a relatively understudied taxon in ecotoxicology. To conduct ecological risk assessments on reptiles frequently requires using surrogate taxa such as birds, but recent research suggests that reptiles have significantly different exposure profiles and toxicant sensitivity. We exposed western fence lizards, Sceloporus occidentalis, to the same quantities of three model chemicals via oral (gavage) and dermal (ventral skin application) exposure for either 24 or 48 hours. Three phthalate esters (di-methyl phthalate [DMP], di-iso-butyl phthalate [DIBP], and di-n-octyl phthalate [DNOP]) were chosen as model chemicals because they represent a gradient of lipophilicity but are otherwise structurally similar. Overall, the more lipophilic phthalates (DIBP and DNOP) were found to have higher concentrations in tissues than the less lipophilic DMP. Significant differences in tissue concentrations between DIBP and DNOP were tissue-dependent, suggesting that delivery to a site of action following exposure is not only a simple function of lipophilicity. In dermal treatments, DMP usually had fewer detections (except in ventral skin samples), suggesting that lipophilicity (log Kow>2) is a requirement for uptake across the skin. In general, tissue residues were greater in oral treatments than dermal treatments (significant in adipose and liver tissue), but differences were driven strongly by differences in DMP which did not appear to be absorbed well across skin. When differences in tissue residue concentrations between oral and dermal exposure did occur, the difference was not drastic. Taken together these results suggest that dermal exposure should be considered in risk assessments for reptilian receptors. Dermal exposure may be an especially important route for reptiles as their ectothermic physiology translates to lower energetic demands and dietary exposure compared to birds and mammals.

A Web-based Tool to Aid the Identification of Chemicals Potentially Posing a Health Risk through Percutaneous Exposure.

PubMed

Gorman Ng, Melanie; Milon, Antoine; Vernez, David; Lavoué, Jérôme

2016-04-01

Occupational hygiene practitioners typically assess the risk posed by occupational exposure by comparing exposure measurements to regulatory occupational exposure limits (OELs). In most jurisdictions, OELs are only available for exposure by the inhalation pathway. Skin notations are used to indicate substances for which dermal exposure may lead to health effects. However, these notations are either present or absent and provide no indication of acceptable levels of exposure. Furthermore, the methodology and framework for assigning skin notation differ widely across jurisdictions resulting in inconsistencies in the substances that carry notations. The UPERCUT tool was developed in response to these limitations. It helps occupational health stakeholders to assess the hazard associated with dermal exposure to chemicals. UPERCUT integrates dermal quantitative structure-activity relationships (QSARs) and toxicological data to provide users with a skin hazard index called the dermal hazard ratio (DHR) for the substance and scenario of interest. The DHR is the ratio between the estimated 'received' dose and the 'acceptable' dose. The 'received' dose is estimated using physico-chemical data and information on the exposure scenario provided by the user (body parts exposure and exposure duration), and the 'acceptable' dose is estimated using inhalation OELs and toxicological data. The uncertainty surrounding the DHR is estimated with Monte Carlo simulation. Additional information on the selected substances includes intrinsic skin permeation potential of the substance and the existence of skin notations. UPERCUT is the only available tool that estimates the absorbed dose and compares this to an acceptable dose. In the absence of dermal OELs it provides a systematic and simple approach for screening dermal exposure scenarios for 1686 substances. © The Author 2015. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Validation and comparison of two sampling methods to assess dermal exposure to drilling fluids and crude oil.

PubMed

Galea, Karen S; McGonagle, Carolyn; Sleeuwenhoek, Anne; Todd, David; Jiménez, Araceli Sánchez

2014-06-01

Dermal exposure to drilling fluids and crude oil is an exposure route of concern. However, there have been no published studies describing sampling methods or reporting dermal exposure measurements. We describe a study that aimed to evaluate a wipe sampling method to assess dermal exposure to an oil-based drilling fluid and crude oil, as well as to investigate the feasibility of using an interception cotton glove sampler for exposure on the hands/wrists. A direct comparison of the wipe and interception methods was also completed using pigs' trotters as a surrogate for human skin and a direct surface contact exposure scenario. Overall, acceptable recovery and sampling efficiencies were reported for both methods, and both methods had satisfactory storage stability at 1 and 7 days, although there appeared to be some loss over 14 days. The methods' comparison study revealed significantly higher removal of both fluids from the metal surface with the glove samples compared with the wipe samples (on average 2.5 times higher). Both evaluated sampling methods were found to be suitable for assessing dermal exposure to oil-based drilling fluids and crude oil; however, the comparison study clearly illustrates that glove samplers may overestimate the amount of fluid transferred to the skin. Further comparison of the two dermal sampling methods using additional exposure situations such as immersion or deposition, as well as a field evaluation, is warranted to confirm their appropriateness and suitability in the working environment. © The Author 2014. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Dermal uptake of phthalates from clothing: Comparison of model to human participant results.

PubMed

Morrison, G C; Weschler, C J; Bekö, G

2017-05-01

In this research, we extend a model of transdermal uptake of phthalates to include a layer of clothing. When compared with experimental results, this model better estimates dermal uptake of diethylphthalate and di-n-butylphthalate (DnBP) than a previous model. The model predictions are consistent with the observation that previously exposed clothing can increase dermal uptake over that observed in bare-skin participants for the same exposure air concentrations. The model predicts that dermal uptake from clothing of DnBP is a substantial fraction of total uptake from all sources of exposure. For compounds that have high dermal permeability coefficients, dermal uptake is increased for (i) thinner clothing, (ii) a narrower gap between clothing and skin, and (iii) longer time intervals between laundering and wearing. Enhanced dermal uptake is most pronounced for compounds with clothing-air partition coefficients between 10 4 and 10 7 . In the absence of direct measurements of cotton cloth-air partition coefficients, dermal exposure may be predicted using equilibrium data for compounds in equilibrium with cellulose and water, in combination with computational methods of predicting partition coefficients. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The margin of internal exposure (MOIE) concept for dermal risk assessment based on oral toxicity data - A case study with caffeine.

PubMed

Bessems, Jos G M; Paini, Alicia; Gajewska, Monika; Worth, Andrew

2017-12-01

Route-to-route extrapolation is a common part of human risk assessment. Data from oral animal toxicity studies are commonly used to assess the safety of various but specific human dermal exposure scenarios. Using theoretical examples of various user scenarios, it was concluded that delineation of a generally applicable human dermal limit value is not a practicable approach, due to the wide variety of possible human exposure scenarios, including its consequences for internal exposure. This paper uses physiologically based kinetic (PBK) modelling approaches to predict animal as well as human internal exposure dose metrics and for the first time, introduces the concept of Margin of Internal Exposure (MOIE) based on these internal dose metrics. Caffeine was chosen to illustrate this approach. It is a substance that is often found in cosmetics and for which oral repeated dose toxicity data were available. A rat PBK model was constructed in order to convert the oral NOAEL to rat internal exposure dose metrics, i.e. the area under the curve (AUC) and the maximum concentration (C max ), both in plasma. A human oral PBK model was constructed and calibrated using human volunteer data and adapted to accommodate dermal absorption following human dermal exposure. Use of the MOIE approach based on internal dose metrics predictions provides excellent opportunities to investigate the consequences of variations in human dermal exposure scenarios. It can accommodate within-day variation in plasma concentrations and is scientifically more robust than assuming just an exposure in mg/kg bw/day. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Porcine dermal lesions produced by 1540-nm laser radiation pulses

NASA Astrophysics Data System (ADS)

Roach, William P.; Johnson, Thomas E.

2001-07-01

Completion of recent studies within our group indicates a breed-based difference in dermal response to 1540 nm 0.8 millisecond laser pulses. Laser exposure to Yucatan Mini- Pigs (highly pigmented skin) and Yorkshire pigs (lightly pigmented skin) demonstrate statistical differences between the ED50's of the two breeds. Laser delivery is accomplished using an Er:Glass system producing 1540 nm of light at millisecond exposure times and in the range of 5 to 95 J/cm2. Dermal lesion development was evaluated for acute, 1 hour, and 24-hour post exposure presentation. Our data contradicts the theory that water absorption is the sole mechanism of dermal tissue damage observed from 1540 nm laser exposures, as skin chromophores appear to play a role in lesion development.

The effects of carbon nanotubes on lung and dermal cellular behaviors

PubMed Central

Luanpitpong, Sudjit; Wang, Liying; Rojanasakul, Yon

2016-01-01

Carbon nanotubes (CNTs) hold great promise to create new and better products, but their adverse health effect is a major concern. Human exposure to CNTs is primarily through inhalation and dermal contact, especially during the manufacturing and handling processes. Numerous animal studies have demonstrated the potential pulmonary and dermal hazards associated with CNT exposure, while in vitro studies have assessed the effects of CNT exposure on various cellular behaviors and have been used to perform mechanistic studies. In this review, we provide an overview of the pathological effects of CNTs and examine the acute and chronic effects of CNT exposure on lung and dermal cellular behaviors, beyond the generally discussed cytotoxicity. We then examine the linkage of cellular behaviors and disease pathogenesis, and discuss the pertinent mechanisms. PMID:24981653

Insights into reptile dermal contaminant exposure: Reptile skin permeability to pesticides.

PubMed

Weir, Scott M; Talent, Larry G; Anderson, Todd A; Salice, Christopher J

2016-07-01

There is growing interest in improving ecological risk assessment exposure estimation, specifically by incorporating dermal exposure. At the same time, there is a growing interest in amphibians and reptiles as receptors in ecological risk assessment, despite generally receiving less research than more traditional receptors. Previous research has suggested that dermal exposure may be more important than previously considered for reptiles. We measured reptile skin permeability to four pesticides (thiamethoxam, malathion, tebuthiuron, trifluralin) using ventral skin samples. All four pesticides penetrated the skin but generally had low permeability. There was no apparent relationship between physicochemical properties and permeability coefficients. Malathion had a significantly greater permeability rate at all time points compared to the other pesticides. Tebuthiuron had a greater permeability than thiamethoxam. Reptiles and mammals appear to have similar skin permeability suggesting that dermal exposure estimates for mammals may be representative of reptiles. Copyright © 2016 Elsevier Ltd. All rights reserved.

A decision tree approach to screen drinking water contaminants for multiroute exposure potential in developing guideline values.

PubMed

Krishnan, Kannan; Carrier, Richard

2017-07-03

The consideration of inhalation and dermal routes of exposures in developing guideline values for drinking water contaminants is important. However, there is no guidance for determining the eligibility of a drinking water contaminant for its multiroute exposure potential. The objective of the present study was to develop a 4-step framework to screen chemicals for their dermal and inhalation exposure potential in the process of developing guideline values. The proposed framework emphasizes the importance of considering basic physicochemical properties prior to detailed assessment of dermal and inhalation routes of exposure to drinking water contaminants in setting guideline values.

The relationship between inadvertent ingestion and dermal exposure pathways: a new integrated conceptual model and a database of dermal and oral transfer efficiencies.

PubMed

Gorman Ng, Melanie; Semple, Sean; Cherrie, John W; Christopher, Yvette; Northage, Christine; Tielemans, Erik; Veroughstraete, Violaine; Van Tongeren, Martie

2012-11-01

Occupational inadvertent ingestion exposure is ingestion exposure due to contact between the mouth and contaminated hands or objects. Although individuals are typically oblivious to their exposure by this route, it is a potentially significant source of occupational exposure for some substances. Due to the continual flux of saliva through the oral cavity and the non-specificity of biological monitoring to routes of exposure, direct measurement of exposure by the inadvertent ingestion route is challenging; predictive models may be required to assess exposure. The work described in this manuscript has been carried out as part of a project to develop a predictive model for estimating inadvertent ingestion exposure in the workplace. As inadvertent ingestion exposure mainly arises from hand-to-mouth contact, it is closely linked to dermal exposure. We present a new integrated conceptual model for dermal and inadvertent ingestion exposure that should help to increase our understanding of ingestion exposure and our ability to simultaneously estimate exposure by the dermal and ingestion routes. The conceptual model consists of eight compartments (source, air, surface contaminant layer, outer clothing contaminant layer, inner clothing contaminant layer, hands and arms layer, perioral layer, and oral cavity) and nine mass transport processes (emission, deposition, resuspension or evaporation, transfer, removal, redistribution, decontamination, penetration and/or permeation, and swallowing) that describe event-based movement of substances between compartments (e.g. emission, deposition, etc.). This conceptual model is intended to guide the development of predictive exposure models that estimate exposure from both the dermal and the inadvertent ingestion pathways. For exposure by these pathways the efficiency of transfer of materials between compartments (for example from surfaces to hands, or from hands to the mouth) are important determinants of exposure. A database of transfer efficiency data relevant for dermal and inadvertent ingestion exposure was developed, containing 534 empirically measured transfer efficiencies measured between 1980 and 2010 and reported in the peer-reviewed and grey literature. The majority of the reported transfer efficiencies (84%) relate to transfer between surfaces and hands, but the database also includes efficiencies for other transfer scenarios, including surface-to-glove, hand-to-mouth, and skin-to-skin. While the conceptual model can provide a framework for a predictive exposure assessment model, the database provides detailed information on transfer efficiencies between the various compartments. Together, the conceptual model and the database provide a basis for the development of a quantitative tool to estimate inadvertent ingestion exposure in the workplace.

Default values for assessment of potential dermal exposure of the hands to industrial chemicals in the scope of regulatory risk assessments.

PubMed

Marquart, Hans; Warren, Nicholas D; Laitinen, Juha; van Hemmen, Joop J

2006-07-01

Dermal exposure needs to be addressed in regulatory risk assessment of chemicals. The models used so far are based on very limited data. The EU project RISKOFDERM has gathered a large number of new measurements on dermal exposure to industrial chemicals in various work situations, together with information on possible determinants of exposure. These data and information, together with some non-RISKOFDERM data were used to derive default values for potential dermal exposure of the hands for so-called 'TGD exposure scenarios'. TGD exposure scenarios have similar values for some very important determinant(s) of dermal exposure, such as amount of substance used. They form narrower bands within the so-called 'RISKOFDERM scenarios', which cluster exposure situations according to the same purpose of use of the products. The RISKOFDERM scenarios in turn are narrower bands within the so-called Dermal Exposure Operation units (DEO units) that were defined in the RISKOFDERM project to cluster situations with similar exposure processes and exposure routes. Default values for both reasonable worst case situations and typical situations were derived, both for single datasets and, where possible, for combined datasets that fit the same TGD exposure scenario. The following reasonable worst case potential hand exposures were derived from combined datasets: (i) loading and filling of large containers (or mixers) with large amounts (many litres) of liquids: 11,500 mg per scenario (14 mg cm(-2) per scenario with surface of the hands assumed to be 820 cm(2)); (ii) careful mixing of small quantities (tens of grams in <1l): 4.1 mg per scenario (0.005 mg cm(-2) per scenario); (iii) spreading of (viscous) liquids with a comb on a large surface area: 130 mg per scenario (0.16 mg cm(-2) per scenario); (iv) brushing and rolling of (relatively viscous) liquid products on surfaces: 6500 mg per scenario (8 mg cm(-2) per scenario) and (v) spraying large amounts of liquids (paints, cleaning products) on large areas: 12,000 mg per scenario (14 mg cm(-2) per scenario). These default values are considered useful for estimating exposure for similar substances in similar situations with low uncertainty. Several other default values based on single datasets can also be used, but lead to estimates with a higher uncertainty, due to their more limited basis. Sufficient analogy in all described parameters of the scenario, including duration, is needed to enable proper use of the default values. The default values lead to similar estimates as the RISKOFDERM dermal exposure model that was based on the same datasets, but uses very different parameters. Both approaches are preferred over older general models, such as EASE, that are not based on data from actual dermal exposure situations.

Hydroquinone PBPK model refinement and application to dermal exposure.

PubMed

Poet, Torka S; Carlton, Betsy D; Deyo, James A; Hinderliter, Paul M

2010-11-01

A physiologically based pharmacokinetic (PBPK) model for hydroquinone (HQ) was refined to include an expanded description of HQ-glucuronide metabolites and a description of dermal exposures to support route-to-route and cross-species extrapolation. Total urinary excretion of metabolites from in vivo rat dermal exposures was used to estimate a percutaneous permeability coefficient (K(p); 3.6×10(-5) cm/h). The human in vivo K(p) was estimated to be 1.62×10(-4) cm/h, based on in vitro skin permeability data in rats and humans and rat in vivo values. The projected total multi-substituted glutathione (which was used as an internal dose surrogate for the toxic glutathione metabolites) was modeled following an exposure scenario based on submersion of both hands in a 5% aqueous solution of HQ (similar to black and white photographic developing solution) for 2 h, a worst-case exposure scenario. Total multi-substituted glutathione following this human dermal exposure scenario was several orders of magnitude lower than the internal total glutathione conjugates in rats following an oral exposure to the rat NOEL of 20 mg/kg. Thus, under more realistic human dermal exposure conditions, it is unlikely that toxic glutathione conjugates (primarily the di- and, to a lesser degree, the tri-glutathione conjugate) will reach significant levels in target tissues. Copyright © 2010. Published by Elsevier Ltd.

77 FR 12727 - Trifloxystrobin; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-02

..., 2 T.W. Alexander Drive, Research Triangle Park, NC 27709. The petition requested that 40 CFR 180.555..., dermal and inhalation exposures. It is a strong dermal sensitizer. In repeated dose tests in rats, the... following pre-natal exposure to rats and rabbits and post-natal exposures to rats. Trifloxystrobin was...

76 FR 69648 - Trifloxystrobin; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-09

... (PP 0F7713) by Bayer CropScience, P.O. Box 12014, 2 T.W. Alexander Dr., Research Triangle Park, NC... single oral, dermal and inhalation exposures. It is a strong dermal sensitizer. In repeated dose tests in... follows: i. Acute exposure. Quantitative acute dietary exposure and risk assessments are performed for a...

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

EPA Science Inventory

High throughput screening (HTS) models are being developed and applied to prioritize chemicals for more comprehensive exposure and risk assessment. Dermal pathways are possible exposure routes to humans for thousands of chemicals found in personal care products and the indoor env...

A COMPARISON OF CYTOKINE MESSAGE AND PROTEIN PROFILES OBTAINED FOLLOWING DERMAL EXPOSURE TO DIISOCYANATES.

EPA Science Inventory

Exposure to certain low molecular weight chemicals is associated with asthma. A simple method to identify this hazard is needed. Increased expression of Th2 cytokine mRNA in draining lymph nodes following dermal exposure and increased production of Th2 cytokines by cultured cell...

THE INDOOR FUGACITY MODEL

EPA Science Inventory

Dermal and non-dietary pathways are potentially significant exposure pathways to pesticides used in the home. The exposure pathways include dermal contact through the hands and skin, ingestion from hand to mouth activities, ingestion through contact with toys and other items, ...

PBTK Modeling Demonstrates Contribution of Dermal and Inhalation Exposure Components to End-Exhaled Breath Concentrations of Naphthalene

PubMed Central

Kim, David; Andersen, Melvin E.; Chao, Yi-Chun E.; Egeghy, Peter P.; Rappaport, Stephen M.; Nylander-French, Leena A.

2007-01-01

Background Dermal and inhalation exposure to jet propulsion fuel 8 (JP-8) have been measured in a few occupational exposure studies. However, a quantitative understanding of the relationship between external exposures and end-exhaled air concentrations has not been described for occupational and environmental exposure scenarios. Objective Our goal was to construct a physiologically based toxicokinetic (PBTK) model that quantitatively describes the relative contribution of dermal and inhalation exposures to the end-exhaled air concentrations of naphthalene among U.S. Air Force personnel. Methods The PBTK model comprised five compartments representing the stratum corneum, viable epidermis, blood, fat, and other tissues. The parameters were optimized using exclusively human exposure and biological monitoring data. Results The optimized values of parameters for naphthalene were a) permeability coefficient for the stratum corneum 6.8 × 10−5 cm/hr, b) permeability coefficient for the viable epidermis 3.0 × 10−3 cm/hr, c) fat:blood partition coefficient 25.6, and d) other tissue:blood partition coefficient 5.2. The skin permeability coefficient was comparable to the values estimated from in vitro studies. Based on simulations of workers’ exposures to JP-8 during aircraft fuel-cell maintenance operations, the median relative contribution of dermal exposure to the end-exhaled breath concentration of naphthalene was 4% (10th percentile 1% and 90th percentile 11%). Conclusions PBTK modeling allowed contributions of the end-exhaled air concentration of naphthalene to be partitioned between dermal and inhalation routes of exposure. Further study of inter- and intraindividual variations in exposure assessment is required to better characterize the toxicokinetic behavior of JP-8 components after occupational and/or environmental exposures. PMID:17589597

PBTK modeling demonstrates contribution of dermal and inhalation exposure components to end-exhaled breath concentrations of naphthalene.

PubMed

Kim, David; Andersen, Melvin E; Chao, Yi-Chun E; Egeghy, Peter P; Rappaport, Stephen M; Nylander-French, Leena A

2007-06-01

Dermal and inhalation exposure to jet propulsion fuel 8 (JP-8) have been measured in a few occupational exposure studies. However, a quantitative understanding of the relationship between external exposures and end-exhaled air concentrations has not been described for occupational and environmental exposure scenarios. Our goal was to construct a physiologically based toxicokinetic (PBTK) model that quantitatively describes the relative contribution of dermal and inhalation exposures to the end-exhaled air concentrations of naphthalene among U.S. Air Force personnel. The PBTK model comprised five compartments representing the stratum corneum, viable epidermis, blood, fat, and other tissues. The parameters were optimized using exclusively human exposure and biological monitoring data. The optimized values of parameters for naphthalene were a) permeability coefficient for the stratum corneum 6.8 x 10(-5) cm/hr, b) permeability coefficient for the viable epidermis 3.0 x 10(-3) cm/hr, c) fat:blood partition coefficient 25.6, and d) other tissue:blood partition coefficient 5.2. The skin permeability coefficient was comparable to the values estimated from in vitro studies. Based on simulations of workers' exposures to JP-8 during aircraft fuel-cell maintenance operations, the median relative contribution of dermal exposure to the end-exhaled breath concentration of naphthalene was 4% (10th percentile 1% and 90th percentile 11%). PBTK modeling allowed contributions of the end-exhaled air concentration of naphthalene to be partitioned between dermal and inhalation routes of exposure. Further study of inter- and intraindividual variations in exposure assessment is required to better characterize the toxicokinetic behavior of JP-8 components after occupational and/or environmental exposures.

INFLUENCE OF MATRIX FORMULATION ON DERMAL PERCUTANEOUS ABSORPTION OF TRIAZOLE FUNGICIDES USING QSAR AND PBPK / PD MODELS

EPA Science Inventory

The objective of this work is to use the Exposure Related Dose Estimating Model (ERDEM) and quantitative structure-activity relationship (QSAR) models to develop an assessment tool for human exposure assessment to triazole fungicides. A dermal exposure route is used for the physi...

ESTIMATING CONTAMINANT DOSE FOR INTERMITTENT DERMAL CONTACT: MODEL DEVELOPMENT, TESTING, AND APPLICATION

EPA Science Inventory

Assessments of aggregate exposure to pesticides and other surface contamination in residential environments are often driven by assumptions about dermal contacts. Accurately predicting cumulative doses from realistic skin contact scenarios requires characterization of exposure sc...

BREATH MEASUREMENT AND MODELS TO ASSESS VOC DERMAL ABSORPTION IN WATER

EPA Science Inventory

Dermal exposure to volatile organic compounds (VOCs) in water results from environmental contamination of surface, ground-, and drinking waters. This exposure occurs both in occupational and residential settings. Compartmental models incorporating body burden measurements have ...

Advective and diffusive dermal processes for estimating terrestrial amphibian pesticide exposure

EPA Science Inventory

Background/Question/Methods Dermal exposure presents a potentially significant but understudied route for pesticide uptake in terrestrial amphibians. Historically, evaluation of pesticide risk to both amphibians and reptiles has been achieved by comparing ingestion and inhalat...

Potential Dermal Exposure to Flonicamid and Risk Assessment of Applicators During Treatment in Apple Orchards.

PubMed

Zhao, Mei-Ai; Yu, Aili; Zhu, Yong-Zhe; Kim, Jeong-Han

2015-01-01

Exposure and risk assessments of flonicamid for applicators were performed in apple orchards in Korea. Fifteen experiments were done with two experienced applicators under typical field conditions using a speed sprayer. In this study, cotton gloves, socks, masks, and dermal patches were used to monitor potential dermal exposure to flonicamid, and personal air samplers with XAD-2 resin and glass fiber filter were used to monitor potential inhalation exposure. The analytical methods were validated for the limit of detection, limit of quantitation, reproducibility, linearity of the calibration curve, and recovery of flonicamid from various exposure matrices. The results were encouraging and acceptable for an exposure study. The applicability of XAD-2 resin was evaluated via a trapping efficiency and breakthrough test. During the mixing/loading, the average total dermal exposure was 22.6 μg of flonicamid, corresponding to 4.5×10(-5)% of the prepared amount. For the spraying, the potential dermal exposure was 9.32 mg, and the ratio to applied amount was 1.9 × 10(-2%). The primary exposed body parts were the thigh (2.90 mg), upper arm (1.75 mg), and lower leg (1.66 mg). By comparison, absorbable quantity of exposure was small, only 1.62 μg (3.2×10(-6)%). The margin of safety (MOS) were calculated for risk assessment, in all sets of trials, MOS > 1, indicating the exposure level of flonicamid was considered to be safe in apple orchards. Although this was a limited study, it provided a good estimate of flonicamid exposure for orchard applicators.

Dermal exposure to chromium in the grinding of stainless and acid-proof steel.

PubMed

Mäkinen, Milja; Linnainmaa, Markku

2004-04-01

The aim of the study was to measure the dermal exposure levels of chromium dust during grinding of stainless and acid-proof steel parts. The potential dermal exposure of the body was measured with a patch sampling method and the actual exposure of hands with a hand-wash method. Simultaneously, personal air samples were also collected. The range of body and hand exposure to chromium dust was 4.04-3406 and 0.72-79.7 mg/h, respectively. Dust was distributed quite evenly to different body parts. Workers using hand-held grinding tools were more exposed than those using band grinders. It was judged that the sampling methods applied in this study gave a realistic estimation of exposure levels, because of the uniform distribution of contamination during grinding. Respiratory exposure was high compared to Finnish occupational exposure limit values.

A decision support framework for characterizing and managing dermal exposures to chemicals during Emergency Management and Operations.

PubMed

Dotson, G Scott; Hudson, Naomi L; Maier, Andrew

2015-01-01

Emergency Management and Operations (EMO) personnel are in need of resources and tools to assist in understanding the health risks associated with dermal exposures during chemical incidents. This article reviews available resources and presents a conceptual framework for a decision support system (DSS) that assists in characterizing and managing risk during chemical emergencies involving dermal exposures. The framework merges principles of three decision-making techniques: 1) scenario planning, 2) risk analysis, and 3) multicriteria decision analysis (MCDA). This DSS facilitates dynamic decision making during each of the distinct life cycle phases of an emergency incident (ie, preparedness, response, or recovery) and identifies EMO needs. A checklist tool provides key questions intended to guide users through the complexities of conducting a dermal risk assessment. The questions define the scope of the framework for resource identification and application to support decision-making needs. The framework consists of three primary modules: 1) resource compilation, 2) prioritization, and 3) decision. The modules systematically identify, organize, and rank relevant information resources relating to the hazards of dermal exposures to chemicals and risk management strategies. Each module is subdivided into critical elements designed to further delineate the resources based on relevant incident phase and type of information. The DSS framework provides a much needed structure based on contemporary decision analysis principles for 1) documenting key questions for EMO problem formulation and 2) a method for systematically organizing, screening, and prioritizing information resources on dermal hazards, exposures, risk characterization, and management.

A decision support framework for characterizing and managing dermal exposures to chemicals during Emergency Management and Operations

PubMed Central

Dotson, G. Scott; Hudson, Naomi L.; Maier, Andrew

2016-01-01

Emergency Management and Operations (EMO) personnel are in need of resources and tools to assist in understanding the health risks associated with dermal exposures during chemical incidents. This article reviews available resources and presents a conceptual framework for a decision support system (DSS) that assists in characterizing and managing risk during chemical emergencies involving dermal exposures. The framework merges principles of three decision-making techniques: 1) scenario planning, 2) risk analysis, and 3) multicriteria decision analysis (MCDA). This DSS facilitates dynamic decision making during each of the distinct life cycle phases of an emergency incident (ie, preparedness, response, or recovery) and identifies EMO needs. A checklist tool provides key questions intended to guide users through the complexities of conducting a dermal risk assessment. The questions define the scope of the framework for resource identification and application to support decision-making needs. The framework consists of three primary modules: 1) resource compilation, 2) prioritization, and 3) decision. The modules systematically identify, organize, and rank relevant information resources relating to the hazards of dermal exposures to chemicals and risk management strategies. Each module is subdivided into critical elements designed to further delineate the resources based on relevant incident phase and type of information. The DSS framework provides a much needed structure based on contemporary decision analysis principles for 1) documenting key questions for EMO problem formulation and 2) a method for systematically organizing, screening, and prioritizing information resources on dermal hazards, exposures, risk characterization, and management. PMID:26312660

The role of the chemical burns caused by hydroxide ion in the toxicity of dermal exposure to tetramethylammonium ion in a rat model.

PubMed

Wu, Chen-Long; Su, Shih-Bin; Lien, Hsiao-Yin; Guo, How-Ran

2012-11-01

To evaluate the role of the chemical burns caused by hydroxide ion in the fatal effects of tetramethylammonium ion (TMA) in dermal exposure to tetramethylammonium hydroxide (TMAH), we conducted a rat study consisting of two-step treatments with dermal exposure to NaOH and tetramethylammonium chloride (TMACl). In the first step, NaOH or saline was administered in the gauze on the shaved skin for 5 min, and in the second step, TMAH, TMACl, or saline was administered in the same way. The mean blood pressure (MBP), heart rate (HR), and survival in rats were compared among seven groups. Dermal exposure to saline and then 2.75 M TMACl introduced limited and temporary non-fatal effects. Exposure to 2.75 M NaOH and then saline had almost no effects and caused no deaths. Treatments with more concentrated NaOH or TMACl resulted in suppressions of MBP and HR, and deaths were observed after the dosing of TMACl. The toxicity of dermal exposure to TMA alone is limited, but fatal effects can be introduced by pre-treatment with hydroxide ion. Therefore, the chemical burn caused by hydroxide ion plays an essential role in the toxicity, implicating that effective neutralizing may help decreasing the fatality rate. Copyright © 2012 Elsevier Ltd and ISBI. All rights reserved.

A FUGACITY-BASED INDOOR RESIDENTIAL PESTICIDE FATE MODEL

EPA Science Inventory

Dermal and non-dietary pathways are potentially significant exposure pathways to pesticides used in the home. Exposure pathways include dermal contact of pesticide residues with the hands and skin, ingestion from hand-to-mouth activities, ingestion through contact with toys an...

PULMONARY HYPERRESPONSIVENESS FOLLOWING DERMAL EXPOSURE TO SELECTED DIISOCYANATES

EPA Science Inventory

PULMONARY HYPERRESPONSIVENESS FOLLOWING DERMAL EXPOSURE TO SELECTED DIISOCYANATES

M.J.K. Selgrade, E.H. Boykin, N.H. Coates, D.L. Doerfler, S.H. Gavett
Experimental Toxicology Div., National Health and Environmental Research Laboratory, Office of Research and Developmen...

Risk assessment of local dermal effects and skin sensitisation under the EU Chemicals Regulation REACH: a proposal for a qualitative, exposure scenario specific, approach.

PubMed

Schaafsma, G; Hertsenberg, A J; Marquart, J

2011-08-01

Within the framework of REACH, an assessment regarding local dermal effects and skin sensitisation should be performed for substances. Quantitative hazard information for these effects is often not available. Furthermore, it is difficult to relate the way in which animals are exposed in dermal toxicity studies directly to dermal exposure in practice. In the absence of quantitative information, a qualitative assessment for dermal effects is the most reasonable option. The qualitative approach as proposed in the REACH guidance recommends only general risk management measures (RMM) for three categories with a low, moderate and high identified hazard, without specifying which RMM are needed for a specific exposure scenario. We propose to differentiate frequency of exposure based on differences in activities and to compare measured and estimated local skin exposure levels with rules of thumb for evaluation of control of risks per hazard category. For workers, specific RMM regimes are assigned to each combination of hazard category and process category (PROC). For consumers, a strategy in which RMM are arranged from product-integrated measures to the use of personal protective equipment (PPE) is presented. Our approach may be transferred into automated assessment tools like Chesar and CEFIC GES. Copyright © 2011 Elsevier Inc. All rights reserved.

Exploratory breath analyses for assessing toxic dermal exposures of firefighters during suppression of structural burns.

PubMed

Pleil, Joachim D; Stiegel, Matthew A; Fent, Kenneth W

2014-09-01

Firefighters wear fireproof clothing and self-contained breathing apparatus (SCBA) during rescue and fire suppression activities to protect against acute effects from heat and toxic chemicals. Fire services are also concerned about long-term health outcomes from chemical exposures over a working lifetime, in particular about low-level exposures that might serve as initiating events for adverse outcome pathways (AOP) leading to cancer. As part of a larger US National Institute for Occupational Safety and Health (NIOSH) study of dermal exposure protection from safety gear used by the City of Chicago firefighters, we collected pre- and post-fire fighting breath samples and analyzed for single-ring and polycyclic aromatic hydrocarbons as bioindicators of occupational exposure to gas-phase toxicants. Under the assumption that SCBA protects completely against inhalation exposures, any changes in the exhaled profile of combustion products were attributed to dermal exposures from gas and particle penetration through the protective clothing. Two separate rounds of firefighting activity were performed each with 15 firefighters per round. Exhaled breath samples were collected onto adsorbent tubes and analyzed with gas-chromatography-mass spectrometry (GC-MS) with a targeted approach using selective ion monitoring. We found that single ring aromatics and some PAHs were statistically elevated in post-firefighting samples of some individuals, suggesting that fire protective gear may allow for dermal exposures to airborne contaminants. However, in comparison to a previous occupational study of Air Force maintenance personnel where similar compounds were measured, these exposures are much lower suggesting that firefighters' gear is very effective. This study suggests that exhaled breath sampling and analysis for specific targeted compounds is a suitable method for assessing systemic dermal exposure in a simple and non-invasive manner.

Dinitrotoluene exposure in the copper mining industry and renal cancer: a case-cohort study.

PubMed

Seidler, Andreas; Harth, Volker; Taeger, Dirk; Möhner, Matthias; Gawrych, Katarzyna; Bergmann, Annekatrin; Haerting, Johannes; Kahmann, Hans-Joachim; Bolt, Hermann Maximilian; Straif, Kurt; Brüning, Thomas

2014-04-01

To evaluate the association between dinitrotoluene (DNT) exposure and renal cancer in a case-cohort study. This case-cohort study was conducted among men born between 1920 and 1974 (n=16 441) who were gainfully employed between 1953 and 1990 in one of two copper mines in Mansfeld, Saxony-Anhalt, former German Democratic Republic, and followed up till 31 December 2006. The study included 109 cases with renal cancer identified by record linkage with the Common Cancer Registry of the New Federal States of Germany (GKR) or by a network of pathology institutes. A comparison subcohort of 999 cohort members was selected at random from the total cohort. Duration and intensity of inhalation and dermal exposure to DNT were assessed on the basis of a job exposure matrix. A time-dependent Cox proportional hazards model modified for case-cohort design was used to assess the relationship between cumulative inhalation and dermal DNT exposure and renal cancer. Elevated risks were found for medium (HR=2.73; 95% CI 1.00 to 7.42) and high (HR=1.81; 95% CI 0.75 to 4.33) dermal exposure to DNT. Relative risks for medium inhalation exposure to DNT were not increased (HR=0.93; 95% CI 0.48 to 1.79) while relative risks for high inhalation exposure to DNT were elevated to 1.36 (95% CI 0.84 to 2.21). We found a statistically significant HR of 2.12 (95% CI 1.03 to 4.37) for combined medium or high inhalation and medium or high dermal exposure to DNT. According to our case-cohort study, dermal and inhalation exposure to DNT is associated with increased renal cancer risk.

Quantitative plasma biomarker analysis in HDI exposure assessment.

PubMed

Flack, Sheila L; Fent, Kenneth W; Trelles Gaines, Linda G; Thomasen, Jennifer M; Whittaker, Steve; Ball, Louise M; Nylander-French, Leena A

2010-01-01

Quantification of amines in biological samples is important for evaluating occupational exposure to diisocyanates. In this study, we describe the quantification of 1,6-hexamethylene diamine (HDA) levels in hydrolyzed plasma of 46 spray painters applying 1,6-hexamethylene diisocyanate (HDI)-containing paint in vehicle repair shops collected during repeated visits to their workplace and their relationship with dermal and inhalation exposure to HDI monomer. HDA was detected in 76% of plasma samples, as heptafluorobutyryl derivatives, and the range of HDA concentrations was < or =0.02-0.92 microg l(-1). After log-transformation of the data, the correlation between plasma HDA levels and HDI inhalation exposure measured on the same workday was low (N = 108, r = 0.22, P = 0.026) compared with the correlation between plasma HDA levels and inhalation exposure occurring approximately 20 to 60 days before blood collection (N = 29, r = 0.57, P = 0.0014). The correlation between plasma HDA levels and HDI dermal exposure measured on the same workday, although statistically significant, was low (N = 108, r = 0.22, P = 0.040) while the correlation between HDA and dermal exposure occurring approximately 20 to 60 days before blood collection was slightly improved (N = 29, r = 0.36, P = 0.053). We evaluated various workplace factors and controls (i.e. location, personal protective equipment use and paint booth type) as modifiers of plasma HDA levels. Workers using a downdraft-ventilated booth had significantly lower plasma HDA levels relative to semi-downdraft and crossdraft booth types (P = 0.0108); this trend was comparable to HDI inhalation and dermal exposure levels stratified by booth type. These findings indicate that HDA concentration in hydrolyzed plasma may be used as a biomarker of cumulative inhalation and dermal exposure to HDI and for investigating the effectiveness of exposure controls in the workplace.

NHEXAS PHASE I ARIZONA STUDY--STANDARD OPERATING PROCEDURE FOR PROBABILISTIC APPROACH OF EXPOSURE CALCULATION OF DERMAL EXPOSURE (IIT-A-13.0)

EPA Science Inventory

The purpose of this SOP is to describe the procedures undertaken to calculate the dermal exposure using a probabilistic approach. This SOP uses data that have been properly coded and certified with appropriate QA/QC procedures by the University of Arizona NHEXAS and Battelle Labo...

Dermal exposure of applicators to chlorpyrifos on rice farms in Ghana.

PubMed

Atabila, Albert; Phung, Dung Tri; Hogarh, Jonathan N; Osei-Fosu, Paul; Sadler, Ross; Connell, Des; Chu, Cordia

2017-07-01

Studies evaluating dermal exposure to pesticides among applicators in tropical countries have largely been conducted using the patch dosimetry and hand wiping/washing techniques. This study used the more accurate whole-body dosimetry technique to evaluate dermal exposure to chlorpyrifos among applicators on rice farms in Ghana. The exposure levels were plotted as Cumulative Probability Distribution (CPD). Total Dermal Exposure (TDE) of chlorpyrifos among the median exposed and the 5% highly exposed groups during a spray event were 24 mg and 48 mg, respectively. When these were converted as a percentage of the quantity of active ingredient applied (Unit Exposure, UE), UE values of 0.03% and 0.06% were found among the median exposed and the 5% highly exposed groups, respectively. Overall, the hands were the most contaminated anatomical regions of the applicators, both in terms of proportion of TDE (39%) and skin loading (13 μg/cm 2 ). Also, the lower anatomical region was more contaminated (82% of TDE) compared to the upper anatomical region (18% of TDE). The levels of chlorpyrifos TDE among the applicators were found to be influenced by the quantity of insecticide applied and the height of the crops sprayed (p < 0.05). The pesticide UE data of the present study can be used to estimate the levels of dermal exposure under similar pesticide use scenarios among applicators. The findings of the present study suggest that protecting the hands and the lower anatomical regions with appropriate PPE may significantly reduce exposure among applicators. Copyright © 2017 Elsevier Ltd. All rights reserved.

CONTROLLED, SHORT-TERM DERMAL AND INHALATION EXPOSURE TO CHLOROFORM

EPA Science Inventory

Studies were conducted to determine the uptake by humans of chloroform as a result of controlled short-term dermal and inhalation exposures. The approach used continuous real-time breath analysis to determine exhaled-breath profiles and evaluate chloroform kinetics in the huma...

STUDY TO TEST THE FEASIBILITY OF USING THE MACROACTIVITY APPROACH TO ASSESS DERMAL EXPOSURE

EPA Science Inventory

In the macroactivity approach, dermal exposure is estimated using empirically-derived transfer coefficients to aggregate the mass transfer associated with a series of contacts with a contaminated medium. The macroactivity approach affords the possibility of developing screenin...

APPLICATION OF THE EXPOSURE DOSE ESTIMATING MODEL (ERDEM) TO ASSESSMENT OF DERMAL EXPOSURE IN THE RAT TO MALATHION

EPA Science Inventory

APPLICATION OF THE EXPOSURE DOSE ESTIMATING MODEL (ERDEM) TO ASSESSMENT OF DERMAL EXPOSURE IN THE RAT TO MALATHION.
Evans, M.V1., Power, F.W2., Dary, C.C2., Tornero-Velez, R2., and Blancato, J.N2.
1 NHEERL, US EPA, ORD, ETD, RTP, NC; 2 NERL, US EPA, ORD, EDRB, LV, NV
Re...

The Transient Dermal Exposure II: Post-Exposure Absorption and Evaporation of Volatile Compounds

PubMed Central

FRASCH, H. FREDERICK; BUNGE, ANNETTE L.

2016-01-01

The transient dermal exposure is one where the skin is exposed to chemical for a finite duration, after which the chemical is removed and no residue remains on the skin’s surface. Chemical within the skin at the end of the exposure period can still enter the systemic circulation. If it has some volatility, a portion of it will evaporate from the surface before it has a chance to be absorbed by the body. The fate of this post-exposure “skin depot” is the focus of this theoretical study. Laplace domain solutions for concentration distribution, flux, and cumulative mass absorption and evaporation are presented, and time domain results are obtained through numerical inversion. The Final Value Theorem is applied to obtain the analytical solutions for the total fractional absorption by the body and evaporation from skin at infinite time following a transient exposure. The solutions depend on two dimensionless variables: χ, the ratio of evaporation rate to steady-state dermal permeation rate; and the ratio of exposure time to membrane lag time. Simple closed form algebraic equations are presented that closely approximate the complete analytical solutions. Applications of the theory to the dermal risk assessment of pharmaceutical, occupational, and environmental exposures are presented for four example chemicals. PMID:25611182

Dermal insecticide residues from birds inhabiting an orchard

USGS Publications Warehouse

Vyas, N.B.; Spann, J.W.; Hulse, C.S.; Gentry, S.; Borges, S.L.

2007-01-01

The US Environmental Protection Agency conducts risk assessments of insecticide applications to wild birds using a model that is limited to the dietary route of exposure. However, free-flying birds are also exposed to insecticides via the inhalation and dermal routes. We measured azinphos-methyl residues on the skin plus feathers and the feet of brown-headed cowbirds (Molothrus ater) in order to quantify dermal exposure to songbirds that entered and inhabited an apple (Malus x domestica) orchard following an insecticide application. Exposure to azinphos-methyl was measured by sampling birds from an aviary that was built around an apple tree. Birds sampled at 36 h and 7-day post-application were placed in the aviary within 1 h after the application whereas birds exposed for 3 days were released into the aviary 4-day post-application. Residues on vegetation and soil were also measured. Azinphos-methyl residues were detected from the skin plus feathers and the feet from all exposure periods. Our results underscore the importance of incorporating dermal exposure into avian pesticide risk assessments.

Dermal Exposure Assessment to Pesticides in Farming Systems in Developing Countries: Comparison of Models

PubMed Central

Lesmes Fabian, Camilo; Binder, Claudia R.

2015-01-01

In the field of occupational hygiene, researchers have been working on developing appropriate methods to estimate human exposure to pesticides in order to assess the risk and therefore to take the due decisions to improve the pesticide management process and reduce the health risks. This paper evaluates dermal exposure models to find the most appropriate. Eight models (i.e., COSHH, DERM, DREAM, EASE, PHED, RISKOFDERM, STOFFENMANAGER and PFAM) were evaluated according to a multi-criteria analysis and from these results five models (i.e., DERM, DREAM, PHED, RISKOFDERM and PFAM) were selected for the assessment of dermal exposure in the case study of the potato farming system in the Andean highlands of Vereda La Hoya, Colombia. The results show that the models provide different dermal exposure estimations which are not comparable. However, because of the simplicity of the algorithm and the specificity of the determinants, the DERM, DREAM and PFAM models were found to be the most appropriate although their estimations might be more accurate if specific determinants are included for the case studies in developing countries. PMID:25938911

USE OF THE MACROACTIVITY APPROACH TO ASSESS CHILDREN'S DERMAL EXPOSURE TO PESTICIDES IN RESIDENTIAL ENVIRONMENTS

EPA Science Inventory

In the macroactivity approach, dermal exposure is estimated using empirically-derived transfer coefficients (TC) to aggregate the mass transfer associated with a series of contacts with a contaminated medium. The macroactivity approach affords the possibility of developing scr...

DERMAL EXPOSURE ASSESSMENT: A SUMMARY OF EPA APPROACHES

EPA Science Inventory

This final report presents a concise description and evaluation of the approaches used in the Agency for dermal exposure assessment including a discussion about harmonization and research needs in this area. The report is intended to be used by EPA program offices in their effort...

Inhalational and dermal exposures during spray application of biocides.

PubMed

Berger-Preiss, Edith; Boehncke, Andrea; Könnecker, Gustav; Mangelsdorf, Inge; Holthenrich, Dagmar; Koch, Wolfgang

2005-01-01

Data on inhalational and potential dermal exposures during spray application of liquid biocidal products were generated. On the one hand, model experiments with different spraying devices using fluorescent tracers were carried out to investigate the influence of parameters relevant to the exposure (e.g. spraying equipment, nozzle size, direction of application). On the other hand, measurements were performed at selected workplaces (during disinfection operations in food and feed areas; pest control operations for private, public and veterinary hygiene; wood protection and antifouling applications) after application of biocidal products such as Empire 20, Responsar SC, Omexan-forte, Actellic, Perma-forte; Fendona SC, Pyrethrum mist; CBM 8, Aldekol Des 03, TAD CID, Basileum, Basilit. The measurements taken in the model rooms demonstrated dependence of the inhalation exposure on the type of spraying device used, in the following order: "spraying with low pressure" < "airless spraying" < "fogging" indicating that the particle diameter of the released spray droplets is the most important parameter. In addition inhalation exposure was lowest when the spraying direction was downward. Also for the potential dermal exposure, the spraying direction was of particular importance: overhead spraying caused the highest contamination of body surfaces. The data of inhalational and potential dermal exposures gained through workplace measurements showed considerable variation. During spraying procedures with low-pressure equipments, dose rates of active substances inhaled by the operators ranged from 7 to 230 microg active substance (a.s.)/h. An increase in inhaled dose rates (6-33 mg a.s./h) was observed after use of high application volumes/time unit during wood protection applications indoors. Spraying in the veterinary sector using medium-pressure sprayers led to inhaled dose rates between 2 and 24mga.s./h. The highest inhaled dose rates were measured during fogging (114 mg a.s./h) and after-high-pressure applications in the antifouling sector (110-300 mg a.s./h). The potential dermal exposure of spray operators was lowest (dose rates from 0.2 to 7 mg a.s./h) in the areas of food and feed disinfection and private and public hygiene during spraying with low-pressure devices. During fogging, wood protection and antifouling applications, high-potential dermal exposures of the operators were determined. Dermal dose rates varied between 100 and 34,000 mg a.s./h.

Effect of hydration status on pesticide uptake in anurans following exposure to contaminated soils.

PubMed

Glinski, Donna A; Henderson, W Matthew; Van Meter, Robin J; Purucker, S Thomas

2018-06-01

In this study, the impact of hydration status on dermal uptake of pesticides in two species of amphibians is examined. Absorption of pesticides in anurans occurs primarily through a highly vascularized dermal seat patch; however, pesticides can also enter through the superficial dermis following exposure. Despite the growing body of literature on dermal exposure in amphibians, little is known on how hydration status influences uptake. Thus, the objective of this study was to investigate the influence of hydration status on absorption of pesticides (atrazine, triadimefon, metolachlor, chlorothalonil, and imidacloprid) in southern leopard frogs (Lithobates sphenocephala) and Fowler's toads (Anaxyrus fowleri). Amphibian treatments included dehydration periods of 0, 2, 4, 6, 8, or 10 h prior to exposure to pesticide-contaminated soils for 8 h. Following exposure, soil and whole-body homogenates were extracted and analyzed by LC-MS/MS. Dehydration time was then regressed against post-exposure concentrations to infer the impact of dehydration on dermal pesticide uptake. Increased dehydration time resulted in significantly lowered pesticide concentrations in both species (F 6, 293  = 67.66, p = 0.007) for the five pesticides studied. This phenomenon could be due to an energy and/or dilution effect.

Evaluation of Veriox as a Skin Decontamination Product after Dermal Exposure to the Nerve Agent VX

DTIC Science & Technology

2016-09-01

in hair -clipped, unanesthetized guinea pigs. Efficacy was established by generating VX dose-lethality curves for each DC product based on 24 survival...This study compared the effectiveness of Veriox® to RSDL when each was used as a DC product 2 min after dermal exposure to VX in hair -clipped...by the dermal LD90 of VX in untreated animals. A LD90 value of 188 μg/kg generated in hair -clipped, unanesthetized guinea pigs (Clarkson, personal

A dermatotoxicokinetic model of human exposures to jet fuel.

PubMed

Kim, David; Andersen, Melvin E; Nylander-French, Leena A

2006-09-01

Workers, both in the military and the commercial airline industry, are exposed to jet fuel by inhalation and dermal contact. We present a dermatotoxicokinetic (DTK) model that quantifies the absorption, distribution, and elimination of aromatic and aliphatic components of jet fuel following dermal exposures in humans. Kinetic data were obtained from 10 healthy volunteers following a single dose of JP-8 to the forearm over a surface area of 20 cm2. Blood samples were taken before exposure (t = 0 h), after exposure (t = 0.5 h), and every 0.5 h for up to 3.5 h postexposure. The DTK model that best fit the data included five compartments: (1) surface, (2) stratum corneum (SC), (3) viable epidermis, (4) blood, and (5) storage. The DTK model was used to predict blood concentrations of the components of JP-8 based on dermal-exposure measurements made in occupational-exposure settings in order to better understand the toxicokinetic behavior of these compounds. Monte Carlo simulations of dermal exposure and cumulative internal dose demonstrated no overlap among the low-, medium-, and high-exposure groups. The DTK model provides a quantitative understanding of the relationship between the mass of JP-8 components in the SC and the concentrations of each component in the systemic circulation. The model may be used for the development of a toxicokinetic modeling strategy for multiroute exposure to jet fuel.

NIOSH comments to DOL on the occupational safety and health advance notice of proposed rulemaking: Occupational exposure to methylene chloride by R. A. Lemen, February 25, 1987

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1987-02-25

The testimony addressed the concerns of NIOSH regarding the advance notice of proposed rulemaking (ANPR) dealing with occupational exposure to methylene-chloride (75092) (MC). Specifically the testimony addressed the studies that OSHA should consider in its assessment of the potential health risks, especially the carcinogenic, chronic neurological, encephalopathic, teratogenic, and mutagenic effects of MC; the dermal absorption studies available and the extent of the potential adverse health effects resulting from dermal exposure; studies or evidence indicating the combined effects of inhalation and dermal exposures; how OSHA should estimate the significance of risk at the current exposure limits; what the permissible exposuremore » levels should be; production and control systems; substitution availability; protective equipment and clothing; worker exposure and monitoring; worker training; and medical surveillance.« less

DEVELOPMENT AND EVALUATION OF AN AGGREGATE SURFACE SAMPLING METHOD FOR USE IN ASSESSING DERMAL EXPOSURES OF YOUNG CHILDREN

EPA Science Inventory

In the macroactivity approach, dermal exposure is estimated using empirically-derived transfer coefficients to aggregate the mass transfer associated with a series of contacts with a contaminated medium. The macroactivity approach affords the possibility of developing screenin...

40 CFR 798.4100 - Dermal sensitization.

Code of Federal Regulations, 2014 CFR

2014-07-01

... system selected is recommended; (ii) Animals may act as their own controls or groups of induced animals... CONTROL ACT (CONTINUED) HEALTH EFFECTS TESTING GUIDELINES Specific Organ/Tissue Toxicity § 798.4100 Dermal... hypersensitive state is developed. (3) Induction exposure is an experimental exposure of a subject to a test...

40 CFR 798.4100 - Dermal sensitization.

Code of Federal Regulations, 2012 CFR

2012-07-01

... system selected is recommended; (ii) Animals may act as their own controls or groups of induced animals... CONTROL ACT (CONTINUED) HEALTH EFFECTS TESTING GUIDELINES Specific Organ/Tissue Toxicity § 798.4100 Dermal... hypersensitive state is developed. (3) Induction exposure is an experimental exposure of a subject to a test...

40 CFR 798.4100 - Dermal sensitization.

Code of Federal Regulations, 2013 CFR

2013-07-01

... system selected is recommended; (ii) Animals may act as their own controls or groups of induced animals... CONTROL ACT (CONTINUED) HEALTH EFFECTS TESTING GUIDELINES Specific Organ/Tissue Toxicity § 798.4100 Dermal... hypersensitive state is developed. (3) Induction exposure is an experimental exposure of a subject to a test...

40 CFR 798.4100 - Dermal sensitization.

Code of Federal Regulations, 2011 CFR

2011-07-01

... system selected is recommended; (ii) Animals may act as their own controls or groups of induced animals... CONTROL ACT (CONTINUED) HEALTH EFFECTS TESTING GUIDELINES Specific Organ/Tissue Toxicity § 798.4100 Dermal... hypersensitive state is developed. (3) Induction exposure is an experimental exposure of a subject to a test...

40 CFR 799.9325 - TSCA 90-day dermal toxicity.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Health Effects Test Guidelines § 799.9325 TSCA 90-day dermal toxicity. (a) Scope. This section is...-observed-effects level (NOEL) and toxic effects associated with continuous or repeated exposure to a test... human exposure. (b) Source. The source material used in developing this TSCA test guideline is the...

40 CFR 799.9325 - TSCA 90-day dermal toxicity.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Health Effects Test Guidelines § 799.9325 TSCA 90-day dermal toxicity. (a) Scope. This section is...-observed-effects level (NOEL) and toxic effects associated with continuous or repeated exposure to a test... human exposure. (b) Source. The source material used in developing this TSCA test guideline is the...

40 CFR 799.9325 - TSCA 90-day dermal toxicity.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Health Effects Test Guidelines § 799.9325 TSCA 90-day dermal toxicity. (a) Scope. This section is...-observed-effects level (NOEL) and toxic effects associated with continuous or repeated exposure to a test... human exposure. (b) Source. The source material used in developing this TSCA test guideline is the...

40 CFR 799.9325 - TSCA 90-day dermal toxicity.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Health Effects Test Guidelines § 799.9325 TSCA 90-day dermal toxicity. (a) Scope. This section is...-observed-effects level (NOEL) and toxic effects associated with continuous or repeated exposure to a test... human exposure. (b) Source. The source material used in developing this TSCA test guideline is the...

40 CFR 799.9325 - TSCA 90-day dermal toxicity.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Health Effects Test Guidelines § 799.9325 TSCA 90-day dermal toxicity. (a) Scope. This section is...-observed-effects level (NOEL) and toxic effects associated with continuous or repeated exposure to a test... human exposure. (b) Source. The source material used in developing this TSCA test guideline is the...

ESTIMATING CHILDREN'S DERMAL AND NON-DIETARY INGESTION EXPOSURE AND DOSE WITH EPA'S SHEDS MODEL

EPA Science Inventory

A physically-based stochastic model (SHEDS) has been developed to estimate pesticide exposure and dose to children via dermal residue contact and non-dietary ingestion. Time-location-activity data are sampled from national survey results to generate a population of simulated ch...

CYTOKINE PROFILES DO NOT PREDICT ANTIBODY RESPONSES AND RESPIRATORY HYPERRESPONSIVENESS FOLLOWING DERMAL EXPOSURE TO ISOCYANATES

EPA Science Inventory

Rationale: Cytokine profiling of local lymph node responses following dermal exposure has been proposed as a test to identify chemicals that pose a risk of occupational asthma. The present study tested the hypothesis that relative differences in cytokine profiles for dini...

MODELED RESIDENTIAL CHLORPYRIFOS EXPOSURE AND DOSE TO CHILDREN VIA DERMAL SURFACE RESIDUE CONTACT AND NON-DIETARY INGESTION

EPA Science Inventory

A physically-based stochastic model has been applied to estimate residential chlorpyrifos exposure and dace to children via the non-dietary ingestion and dermal residue contact pathways. Time-location-activity data for 2825 children were sampled from national surveys to generat...

HAND WIPE SUBSAMPLING METHOD FOR USE WITH BIOMARKER MEASUREMENTS IN THE AGRICULTURAL HEALTH STUDY/PESTICIDE EXPOSURE STUDY

EPA Science Inventory

Dermal exposure studies incorporating urinary biomarker measurements are complicated because dermal sampling may intercept or remove the target chemical before it is absorbed. A hand wipe subsampling method has been developed using polyurethane foam-tipped (PUF) swabs to minim...

Dermal, oral, and inhalation pharmacokinetics of methyl tertiary butyl ether (MTBE) in human volunteers.

PubMed

Prah, James; Ashley, David; Blount, Benjamin; Case, Martin; Leavens, Teresa; Pleil, Joachim; Cardinali, Frederick

2004-02-01

Methyl tertiary butyl ether (MTBE), a gasoline additive used to increase octane and reduce carbon monoxide emissions and ozone precursors, has contaminated drinking water and can lead to exposure by oral, inhalation, and dermal routes. To determine its dermal, oral, and inhalation kinetics, 14 volunteers were exposed to 51.3 microg/ml MTBE dermally in tap water for 1 h, drank 2.8 mg MTBE in 250 ml Gatorade(R), and inhaled 3.1 ppm. MTBE for 1 h. Blood and exhaled breath samples were then obtained. Blood MTBE peaked between 15 and 30 min following oral exposure, at the end of inhalation exposure, and ~5 min after dermal exposure. Elimination by each route was described well by a three-compartment model (Rsq >0.9). The Akaike Information Criterion for the three-compartment model was smaller than the two-compartment model, supporting it over the two-compartment model. One metabolite, tertiary butyl alcohol (TBA), measured in blood slowly increased and plateaued, but it did not return to the pre-exposure baseline at the 24-h follow-up. TBA is very water-soluble and has a blood:air partition ratio of 462, reducing elimination by exhalation. Oral exposure resulted in a significantly greater MTBE metabolism into TBA than by other routes based on a greater blood TBA:MTBE AUC ratio, implying significant first-pass metabolism. The slower TBA elimination may make it a better biomarker of MTBE exposure, though one must consider the exposure route when estimating MTBE exposure from TBA because of first-pass metabolism. Most subjects had a baseline blood TBA of 1-3 ppb. Because TBA is found in consumer products and can be used as a fuel additive, it is not a definitive marker of MTBE exposure. These data provide the risk assessment process of pharmacokinetic information relevant to the media through which most exposures occur-air and drinking water.

Assessment of dermal exposure and histopathologic changes of different sized nano-silver in healthy adult rabbits

NASA Astrophysics Data System (ADS)

kazem Koohi, Mohammad; Hejazy, Marzie; Asadi, Farzad; Asadian, Peyman

2011-07-01

The purpose of this study is to evaluate the dermal toxicity (Irritation/Corrosion) of three sizes of nanosilver particles (10, 20 and 30 nm) during 3 min, 1 and 4 hours according to the OECD/OCDE guideline Histopathological effects in secondary organs from liver, kidney, heart, spleen and brain 14 day post dermal administration are also reported. 10 and 20 nm Ag nanoparticles treated group showed well defined dermal erythema and oedema. Histopathological findings of 10 and 20 nm (4 hours exposure) on 14-day post dermal administration showed hyperkeratosis, acanthosis, hair-filled follicles and papillomatosis in an irregular epidermis, fibrosis, hyperemia, erythema, intracellular oedema and hyalinisation of collagen in dermis of skin. Liver revealed midzonal and periacinar necrosis, portal mononuclear infiltration, liver fatty change, liver congestion and hyperemic central vein. Splenic red pulp congestion and white pulp hyperreactivity, splenic trabeculae and sinusoidal congestion and hyaline change were found in spleen. Fatty degeneration in some cardiovascular cells and subendocardial hemorrhage without inflammation was perceived. Picnotic appearance of pyramidal neurons in the brain cortex, gliosis and mild perineuronal oedema ischemic cell change and hyperemic meninges was observed in brain. Our research concluded that dermal exposure to lesser sizes of silver nanoparticles is more disastrous than greater ones.

Evaluation of Furfuryl Alcohol Sensitization Potential Following Dermal and Pulmonary Exposure: Enhancement of Airway Responsiveness

PubMed Central

Franko, Jennifer; Jackson, Laurel G.; Hubbs, Ann; Kashon, Michael; Meade, B. J.; Anderson, Stacey E.

2015-01-01

Furfuryl alcohol is considered by the U.S. Environmental Protection Agency to be a high volume production chemical, with over 1 million pounds produced annually. Due to its high production volume and its numerous industrial and consumer uses, there is considerable potential for work-related exposure, as well as exposure to the general population, through pulmonary, oral, and dermal routes of exposure. Human exposure data report a high incidence of asthma in foundry mold workers exposed to furan resins, suggesting potential immunologic effects. Although furfuryl alcohol was nominated and evaluated for its carcinogenic potential by the National Toxicology Program, studies evaluating its immunotoxicity are lacking. The studies presented here evaluated the immunotoxic potential of furfuryl alcohol following exposure by the dermal and pulmonary routes using a murine model. When tested in a combined irritancy local lymph node assay, furfuryl alcohol was identified to be an irritant and mild sensitizer (EC3 = 25.6%). Pulmonary exposure to 2% furfuryl alcohol resulted in enhanced airway hyperreactivity, eosinophilic infiltration into the lungs, and enhanced cytokine production (IL-4, IL-5, and interferon-γ) by ex vivo stimulated lung-associated draining lymphoid cells. Airway hyperreactivity and eosinophilic lung infiltration were augmented by prior dermal exposure to furfuryl alcohol. These results suggest that furfuryl alcohol may play a role in the development of allergic airway disease and encourage the need for additional investigation. PMID:22003193

Chlorpyrifos exposures in Egyptian cotton field workers.

PubMed

Farahat, Fayssal M; Fenske, Richard A; Olson, James R; Galvin, Kit; Bonner, Matthew R; Rohlman, Diane S; Farahat, Taghreed M; Lein, Pamela J; Anger, W Kent

2010-06-01

Neurobehavioral deficits have been reported in Egyptian pesticide application teams using organophosphorus (OP) pesticides, but whether these effects are related to OP pesticide exposures has yet to be established. In preparation for a comprehensive study of the relationship between OP pesticide dose and neurobehavioral deficits, we assessed exposure within this population. We conducted occupational surveys and workplace observations, and collected air, dermal patch and biological samples from applicators, technicians and engineers involved in chlorpyrifos applications during cotton production to test the hypotheses that: (1) dermal exposure was an important contributor to internal dose and varied across body regions; and (2) substantial differences would be seen across the three job categories. Applicators were substantially younger and had shorter exposure histories than did technicians and engineers. Applicators and technicians were observed to have relatively high levels of skin or clothing contact with pesticide-treated foliage as they walked through the fields. Both dermal patch loadings of chlorpyrifos and measurements of a chlorpyrifos-specific metabolite (TCPy) in urine confirmed substantial exposure to and skin absorption of chlorpyrifos that varied according to job category; and dermal patch loading was significantly higher on the thighs than on the forearms. These findings support our hypotheses and support the need for research to examine neurobehavioral performance and exposures in this population. More importantly, the exposures reported here are sufficiently high to recommend urgent changes in work practices amongst these workers. Copyright 2010 Elsevier Inc. All rights reserved.

Chlorpyrifos Exposures in Egyptian Cotton Field Workers

PubMed Central

Farahat, Fayssal M.; Fenske, Richard A.; Olson, James R.; Galvin, Kit; Bonner, Matthew R.; Rohlman, Diane S.; Lein, Pamela J.; Anger, W. Kent

2013-01-01

Neurobehavioral deficits have been reported in Egyptian pesticide application teams using organophosphorus (OP) pesticides, but whether these effects are related to OP pesticide exposures has yet to be established. In preparation for a comprehensive study of the relationship between OP pesticide dose and neurobehavioral deficits, we assessed exposure within this population. We conducted occupational surveys and workplace observations, and collected air, dermal patch and biological samples from applicators, technicians and engineers involved in chlorpyrifos applications during cotton production to test the hypotheses that: 1) dermal exposure was an important contributor to internal dose and varied across body regions; and 2) substantial differences would be seen across the three job categories. Applicators were substantially younger and had shorter exposure histories than did technicians and engineers. Applicators and technicians were observed to have relatively high levels of skin or clothing contact with pesticide-treated foliage as they walked through the fields. Both dermal patch loadings of chlorpyrifos and measurements of a chlorpyrifos-specific metabolite (TCPy) in urine confirmed substantial exposure to and skin absorption of chlorpyrifos that varied according to job category; and dermal patch loading was significantly higher on the thighs than on the forearms. These findings support our hypotheses and support the need for research to examine neurobehavioral performance and exposures in this population. More importantly, the exposures reported here are sufficiently high to recommend urgent changes in work practices amongst these workers. PMID:20193710

DERMAL, ORAL, AND INHALATION PHARMACOKINETICS OF METHYL TERTIARY BUTYL ETHER (MTBE) IN HUMAN VOLUNTEERS

EPA Science Inventory

Methyl tertiary butyl ether (MTBE), a gasoline additive, used to increase octane and reduce carbon monoxide emissions and ozone precursors has contaminated drinking water leading to exposure by oral, inhalation, and dermal routes. To determine its dermal, oral, and inhalation ki...

In vitro dermal absorption of pyrethroid pesticides in human and rat skin

EPA Science Inventory

Dermal exposure to pyrethroid pesticides can occur during manufacture and application. This study examined the in vitro dermal absorption of pyrethroids using rat and human skin. Dermatomed skin from adult male Long Evans rats or human cadavers was mounted in flowthrough diffusi...

Distribution of kerosene components in rats following dermal exposure.

PubMed

Tsujino, Y; Hieda, Y; Kimura, K; Eto, H; Yakabe, T; Takayama, K; Dekio, S

2002-08-01

The systemic distribution of kerosene components in blood and tissues was analysed in rats following dermal exposure. Four types of trimethylbenzenes (TMBs) and aliphatic hydrocarbons (AHCs) with carbon numbers 9-16 (C(9)-C(16)) were analysed as major kerosene components by capillary gas chromatography/mass spectrometry (GC/MS). The kerosene components were detected in blood and all tissues after a small piece of cotton soaked with kerosene was applied to the abdominal skin. The amounts of TMBs detected were higher than those of AHCs. Greater increases in TMB levels were found in adipose tissue in an exposure duration-dependent manner. The amounts of TMBs detected were only at trace levels following post-mortem dermal exposure to kerosene. These findings suggest that kerosene components were absorbed percutaneously and distributed to various organs via the blood circulation. Post-mortem or ante-mortem exposure to kerosene could be distinguished when the exposure duration was relatively long. Adipose tissue would seem to be the most useful for estimating the degree of kerosene exposure.

Exposure assessment for trihalomethanes in municipal drinking water and risk reduction strategy.

PubMed

Chowdhury, Shakhawat

2013-10-01

Lifetime exposure to disinfection byproducts (DBPs) in municipal water may pose risks to human health. Current approaches of exposure assessments use DBPs in cold water during showering, while warming of chlorinated water during showering may increase trihalomethane (THM) formation in the presence of free residual chlorine. Further, DBP exposure through dermal contact during showering is estimated using steady-state condition between the DBPs in shower water impacting on human skin and skin exposed to shower water. The lag times to achieve steady-state condition between DBPs in shower water and human skin can vary in the range of 9.8-391.2 min, while shower duration is often less than the lag times. Assessment of exposure without incorporating these factors might have misinterpreted DBP exposure in some previous studies. In this study, exposure to THMs through ingestion was estimated using cold water THMs, while THM exposure through inhalation and dermal contact during showering was estimated using THMs in warm water. Inhalation of THMs was estimated using THM partition into the shower air, while dermal uptake was estimated by incorporating lag times (e.g., unsteady and steady-state phases of exposure) during showering. Probabilistic approach was followed to incorporate uncertainty in the assessment. Inhalation and dermal contact during showering contributed 25-60% of total exposure. Exposure to THMs during showering can be controlled by varying shower stall volume, shower duration and air exchange rate following power law equations. The findings might be useful in understanding exposure to THMs, which can be extended to other volatile compounds in municipal water. © 2013 Elsevier B.V. All rights reserved.

Characterization of occupational exposures to cleaning products used for common cleaning tasks--a pilot study of hospital cleaners.

PubMed

Bello, Anila; Quinn, Margaret M; Perry, Melissa J; Milton, Donald K

2009-03-27

In recent years, cleaning has been identified as an occupational risk because of an increased incidence of reported respiratory effects, such as asthma and asthma-like symptoms among cleaning workers. Due to the lack of systematic occupational hygiene analyses and workplace exposure data, it is not clear which cleaning-related exposures induce or aggravate asthma and other respiratory effects. Currently, there is a need for systematic evaluation of cleaning products ingredients and their exposures in the workplace. The objectives of this work were to: a) identify cleaning products' ingredients of concern with respect to respiratory and skin irritation and sensitization; and b) assess the potential for inhalation and dermal exposures to these ingredients during common cleaning tasks. We prioritized ingredients of concern in cleaning products commonly used in several hospitals in Massachusetts. Methods included workplace interviews, reviews of product Materials Safety Data Sheets and the scientific literature on adverse health effects to humans, reviews of physico-chemical properties of cleaning ingredients, and occupational hygiene observational analyses. Furthermore, the potential for exposure in the workplace was assessed by conducting qualitative assessment of airborne exposures and semi-quantitative assessment of dermal exposures. Cleaning products used for common cleaning tasks were mixtures of many chemicals, including respiratory and dermal irritants and sensitizers. Examples of ingredients of concern include quaternary ammonium compounds, 2-butoxyethanol, and ethanolamines. Cleaning workers are at risk of acute and chronic inhalation exposures to volatile organic compounds (VOC) vapors and aerosols generated from product spraying, and dermal exposures mostly through hands. Cleaning products are mixtures of many chemical ingredients that may impact workers' health through air and dermal exposures. Because cleaning exposures are a function of product formulations and product application procedures, a combination of product evaluation with workplace exposure assessment is critical in developing strategies for protecting workers from cleaning hazards. Our task based assessment methods allowed classification of tasks in different exposure categories, a strategy that can be employed by epidemiological investigations related to cleaning. The methods presented here can be used by occupational and environmental health practitioners to identify intervention strategies.

Characterization of occupational exposures to cleaning products used for common cleaning tasks-a pilot study of hospital cleaners

PubMed Central

2009-01-01

Background In recent years, cleaning has been identified as an occupational risk because of an increased incidence of reported respiratory effects, such as asthma and asthma-like symptoms among cleaning workers. Due to the lack of systematic occupational hygiene analyses and workplace exposure data, it is not clear which cleaning-related exposures induce or aggravate asthma and other respiratory effects. Currently, there is a need for systematic evaluation of cleaning products ingredients and their exposures in the workplace. The objectives of this work were to: a) identify cleaning products' ingredients of concern with respect to respiratory and skin irritation and sensitization; and b) assess the potential for inhalation and dermal exposures to these ingredients during common cleaning tasks. Methods We prioritized ingredients of concern in cleaning products commonly used in several hospitals in Massachusetts. Methods included workplace interviews, reviews of product Materials Safety Data Sheets and the scientific literature on adverse health effects to humans, reviews of physico-chemical properties of cleaning ingredients, and occupational hygiene observational analyses. Furthermore, the potential for exposure in the workplace was assessed by conducting qualitative assessment of airborne exposures and semi-quantitative assessment of dermal exposures. Results Cleaning products used for common cleaning tasks were mixtures of many chemicals, including respiratory and dermal irritants and sensitizers. Examples of ingredients of concern include quaternary ammonium compounds, 2-butoxyethanol, and ethanolamines. Cleaning workers are at risk of acute and chronic inhalation exposures to volatile organic compounds (VOC) vapors and aerosols generated from product spraying, and dermal exposures mostly through hands. Conclusion Cleaning products are mixtures of many chemical ingredients that may impact workers' health through air and dermal exposures. Because cleaning exposures are a function of product formulations and product application procedures, a combination of product evaluation with workplace exposure assessment is critical in developing strategies for protecting workers from cleaning hazards. Our task based assessment methods allowed classification of tasks in different exposure categories, a strategy that can be employed by epidemiological investigations related to cleaning. The methods presented here can be used by occupational and environmental health practitioners to identify intervention strategies. PMID:19327131

IN VITRO DERMAL ABSORPTION OF PYRETHROID PESTICIDES IN RAT AND HUMAN SKIN

EPA Science Inventory

Pyrethriods are a class of neurotoxic pesticides and their use may lead to dermal exposure. This study examined the in vitro dermal absorption of pyrethroids in rat and human skin. Dorsal skin removed from adult male LD rats (hair clipped 24 h previously) was dermatomed and mou...

DERMAL, ORAL AND INHALATION PHARMACOKINETICS OF METHYL TERTIARY-BUTYL ETHER (MTBE) IN HUMAN VOLUNTEERS

EPA Science Inventory

Methyl tertiary butyl ether (MTBE), a gasoline additive used to increase octane and reduce carbon monoxide emissions and ozone precursors, has contaminated drinking water and can lead to exposure by oral, inhalation, and dermal routes. To determine its dermal, oral, and inhal...

DISPOSITION OF BROMODICHLOROMETHANE IN HUMANS FOLLOWING ORAL AND DERMAL EXPOSURE

EPA Science Inventory

DISPOSITION OF BROMODICHLOROMETHANE IN HUMANS FOLLOWING ORAL AND DERMAL EXPOSURE. TL Leavens1, MW Case1, RA Pegram1, BC Blount2, DM DeMarini1, MC Madden1, and JL Valentine3. 1NHEERL, USEPA, RTP, NC, USA; 2CDC, Atlanta, GA, USA; 3RTI, RTP, NC, USA.
The disinfection byproduct ...

A MODELING FRAMEWORK FOR ESTIMATING CHILDREN'S RESIDENTIAL EXPOSURE AND DOSE TO CHLORPYRIFOS VIA DERMAL RESIDUE CONTACT AND NON-DIETARY INGESTION

EPA Science Inventory

To help address the Food Quality Protection Act of 1996, a physically-based probabilistic model (Residential Stochastic Human Exposure and Dose Simulation Model for Pesticides; Residential-SHEDS) has been developed to quantify and analyze dermal and non-dietary ingestion exposu...

NHEXAS PHASE I ARIZONA STUDY--STANDARD OPERATING PROCEDURE FOR DERMAL EXPOSURE CALCULATION (IIT-A-11.0)

EPA Science Inventory

The purpose of this SOP is to describe the procedures undertaken to calculate the dermal exposure to chlorpyrifos and diazinon. This SOP uses data that have been properly coded and certified with appropriate QA/QC procedures by the University of Arizona NHEXAS and Battelle Labora...

Estimating terrestrial amphibian pesticide body burden through dermal exposure.

PubMed

Van Meter, Robin J; Glinski, Donna A; Hong, Tao; Cyterski, Mike; Henderson, W Matthew; Purucker, S Thomas

2014-10-01

Dermal exposure presents a potentially significant but understudied route for pesticide uptake in terrestrial amphibians. Our study measured dermal uptake of pesticides of varying hydrophobicity (logKow) in frogs. Amphibians were indirectly exposed to one of five pesticide active ingredients through contact with contaminated soil: imidacloprid (logKow = 0.57), atrazine (logKow = 2.5), triadimefon (logKow = 3.0), fipronil (logKow = 4.11) or pendimethalin (logKow = 5.18). All amphibians had measurable body burdens at the end of the exposure in concentrations ranging from 0.019 to 14.562 μg/g across the pesticides tested. Atrazine produced the greatest body burdens and bioconcentration factors, but fipronil was more permeable to amphibian skin when application rate was considered. Soil partition coefficient and water solubility were much better predictors of pesticide body burden, bioconcentration factor, and skin permeability than logKow. Dermal uptake data can be used to improve risk estimates of pesticide exposure among amphibians as non-target organisms. Copyright © 2014 Elsevier Ltd. All rights reserved.

Evaluation of Beryllium, Total Chromium and Nickel in the Surface Contaminant Layer Available for Dermal Exposure After Abrasive Blasting in a Shipyard

DTIC Science & Technology

2013-04-24

established to minimize the potential of dermal irritation and dermatitis (6). Chromium exposure can lead to allergic contact dermatitis , irritant... dermatitis with skin contact . (5; 15; 25; 33; 47). Nickel is potentially the most common contact allergen among the general population. Some studies...thresholds - a review focusing on occluded nickel exposure. Contact Dermatitis 52:57-64 21. Fogh CL, Andersson KG. 2000. Modelling of skin exposure

Percutaneous penetration of silver from a silver containing garment in healthy volunteers and patients with atopic dermatitis.

PubMed

Pluut, Olivier A; Bianco, Carlotta; Jakasa, Ivone; Visser, Maaike J; Krystek, Petra; Larese-Filon, Francesca; Rustemeyer, Thomas; Kezic, Sanja

2015-06-01

Human data on dermal absorption of silver under "in use" scenario are scarce which hampers health risk assessment. The main objective of the present study was to determine percutaneous penetration of silver after dermal exposure to silver containing garment in healthy individuals and atopic dermatitis (AD) patients. Next to assess pro-inflammatory effect of silver in the skin. Healthy subjects (n=15) and patients with AD (n=15) wore a sleeve containing 3.6% (w/w) silver on their lower arms for 8h during 5 consecutive days. The percutaneous penetration parameters were deduced from the silver concentration-depth profiles in the stratum corneum (SC) collected by adhesive tapes. Furthermore, silver was measured in urine samples collected before and after exposure. Inflammatory response was assessed by measuring IL-1α and IL-1RA in the exposed and non-exposed skin sites. Dermal flux of silver in healthy subjects and AD patients was respectively 0.23 and 0.20 ng/cm(2)/h. The urine silver concentrations showed no increase after exposure. Furthermore, exposure to silver did not lead to the changes in the profiles of IL-1α and IL-1RA. Dermal absorption of silver under "real life scenario" was lower than the current reference dose. Furthermore, dermal exposure did not lead to altered expression of inflammatory IL-1 cytokines in the skin. Copyright © 2015. Published by Elsevier Ireland Ltd.

Traditional and environmentally preferable cleaning product exposure and health symptoms in custodians

PubMed Central

Cavallari, Jennifer M.; Wakai, Sara; Schenck, Paula; Simcox, Nancy; Morse, Tim; Meyer, John D.; Cherniack, Martin

2015-01-01

Background We investigated the associations between traditional and environmentally preferable cleaning product exposure and dermal, respiratory, and musculoskeletal symptoms in a population of custodians. Methods We analyzed associations between symptoms and exposure to traditional and environmentally preferable cleaning product exposure among 329 custodians. Results We observed increased odds of dermal (P < 0.01), upper (P = 0.01) and lower respiratory (P = 0.01), and upper extremity (P < 0.01), back (P < 0.01), and lower extremity (P = 0.01) musculoskeletal symptoms associated with increased typical traditional cleaning product exposure. We observed significant trends for increased odds of dermal (P = 0.03) and back (P = 0.04) and lower (P = 0.02) extremity musculoskeletal symptoms associated with increased typical environmentally preferable cleaning product exposure. Conclusions Fewer positive associations and reduced odds of health symptoms associated with environmentally preferable cleaning product exposure suggest that these products may represent a safer alternative to traditional cleaning products. Am. J. Ind. Med. 58:988–995, 2015. © 2015 The Authors. American Journal of Industrial Medicine Published by Wiley Periodicals, Inc. PMID:26040239

Aviation Fuel Exposure Resulting in Otitis Externa with Vertigo.

PubMed

Long, Robert J; Charles, Reese A

2018-07-01

Otitis externa secondary to irritant or chemical exposure is well documented; however, specifically secondary to jet fuel exposure and its associated toxicology is not. Over 2 million military and civilian personnel per year are occupationally exposed to aviation fuels. An aircraft maintainer presented with noninfectious acute otitis externa secondary to external ear canal exposure to JP-5 jet fuel. Proper exposure guidelines were followed, but it was not realized that the external ear canal was involved. The first symptoms to emerge were vertigo, dizziness, and disequilibrium; however, on physical exam it appeared that there was no middle ear involvement. Otitis externa normally does not present with vestibular symptoms as the pathology affects the external ear canal dermal tissue. Upon review of JP-5's toxicology profile, dermal absorption is a route of entry and can cause general neurological symptoms, including loss of coordination. This case highlights potential deficiencies in the standardized safety data sheets that are used after exposure. Without mention of possible auricular exposure one may focus on the logical protection of the eyes, mouth, and visible skin. This is concerning due to potential delayed exposure symptoms, dermal absorption, high level of dermal destruction, and the close proximity to the sensory system. The goal of this case report is to improve the knowledge of providers caring for personnel who may be exposed and to suggest possible revisions to the Safety Data Sheets for jet fuel.Long RJ, Charles RA. Aviation fuel exposure resulting in otitis externa with vertigo. Aerosp Med Hum Perform. 2018; 89(7):661-663.

Dermal exposure to monoterpenes during wood work.

PubMed

Eriksson, Kare; Wiklund, Leif

2004-06-01

The dermal exposure to the suspected allergenic monoterpenes [small alpha]-pinene, [small beta]-pinene and [capital Delta](3)-carene was assessed with a patch sampling technique. The patch used was made of activated charcoal sandwiched between two layers of cotton cloth. Patches were fastened at 12 different spots on a sampling overall and at the front of a cap to estimate the potential exposure of the body. Fastening two patches on a cotton glove, one patch representing the dorsal side and one patch representing the palm of the hand respectively, assessed the exposure on the hands. Sampling was carried out during collecting of pine and spruce boards in sawmills and during sawing of pine wood pieces in joinery shops respectively. The potential dermal exposure of the total body was 29.0-1 890 mg h(-1) with a geometric mean (GM) of 238 mg h(-1) during sawing. During collecting the GM was estimated to 100 mg h(-1) with a range of 12.2-959 mg h(-1). The hands had a mean exposure of 9.24 mg h(-1) during sawing and 3.25 mg h(-1) during collecting respectively. The good correlation between the mass of contamination on the individual body parts and the potential body exposure indicates that sampling can be performed on one body part to give a good estimation of the potential body exposure. Monoterpenes were detected at patches fastened underneath the protective clothing indicating a contamination of the skin of the worker. The patch used may overestimate the dermal exposure.

Handling of thermal paper: Implications for dermal exposure to bisphenol A and its alternatives

PubMed Central

Bernier, Meghan R.

2017-01-01

Bisphenol A (BPA) is an endocrine disrupting chemical used in a wide range of consumer products including photoactive dyes used in thermal paper. Recent studies have shown that dermal absorption of BPA can occur when handling these papers. Yet, regulatory agencies have largely dismissed thermal paper as a major source of BPA exposure. Exposure estimates provided by agencies such as the European Food Safety Authority (EFSA) are based on assumptions about how humans interact with this material, stating that ‘typical’ exposures for adults involve only one handling per day for short periods of time (<1 minute), with limited exposure surfaces (three fingertips). The objective of this study was to determine how individuals handle thermal paper in one common setting: a cafeteria providing short-order meals. We observed thermal paper handling in a college-aged population (n = 698 subjects) at the University of Massachusetts’ dining facility. We find that in this setting, individuals handle receipts for an average of 11.5 min, that >30% of individuals hold thermal paper with more than three fingertips, and >60% allow the paper to touch their palm. Only 11% of the participants we observed were consistent with the EFSA model for time of contact and dermal surface area. Mathematical modeling based on handling times we measured and previously published transfer coefficients, concentrations of BPA in paper, and absorption factors indicate the most conservative estimated intake from handling thermal paper in this population is 51.1 ng/kg/day, similar to EFSA’s estimates of 59 ng/kg/day from dermal exposures. Less conservative estimates, using published data on concentrations in thermal paper and transfer rates to skin, indicate that exposures are likely significantly higher. Based on our observational data, we propose that the current models for estimating dermal BPA exposures are not consistent with normal human behavior and should be reevaluated. PMID:28570582

Handling of thermal paper: Implications for dermal exposure to bisphenol A and its alternatives.

PubMed

Bernier, Meghan R; Vandenberg, Laura N

2017-01-01

Bisphenol A (BPA) is an endocrine disrupting chemical used in a wide range of consumer products including photoactive dyes used in thermal paper. Recent studies have shown that dermal absorption of BPA can occur when handling these papers. Yet, regulatory agencies have largely dismissed thermal paper as a major source of BPA exposure. Exposure estimates provided by agencies such as the European Food Safety Authority (EFSA) are based on assumptions about how humans interact with this material, stating that 'typical' exposures for adults involve only one handling per day for short periods of time (<1 minute), with limited exposure surfaces (three fingertips). The objective of this study was to determine how individuals handle thermal paper in one common setting: a cafeteria providing short-order meals. We observed thermal paper handling in a college-aged population (n = 698 subjects) at the University of Massachusetts' dining facility. We find that in this setting, individuals handle receipts for an average of 11.5 min, that >30% of individuals hold thermal paper with more than three fingertips, and >60% allow the paper to touch their palm. Only 11% of the participants we observed were consistent with the EFSA model for time of contact and dermal surface area. Mathematical modeling based on handling times we measured and previously published transfer coefficients, concentrations of BPA in paper, and absorption factors indicate the most conservative estimated intake from handling thermal paper in this population is 51.1 ng/kg/day, similar to EFSA's estimates of 59 ng/kg/day from dermal exposures. Less conservative estimates, using published data on concentrations in thermal paper and transfer rates to skin, indicate that exposures are likely significantly higher. Based on our observational data, we propose that the current models for estimating dermal BPA exposures are not consistent with normal human behavior and should be reevaluated.

Dermal, inhalation, and internal exposure to 1,6-HDI and its oligomers in car body repair shop workers and industrial spray painters.

PubMed

Pronk, A; Yu, F; Vlaanderen, J; Tielemans, E; Preller, L; Bobeldijk, I; Deddens, J A; Latza, U; Baur, X; Heederik, D

2006-09-01

To study inhalation and dermal exposure to hexamethylene diisocyanate (HDI) and its oligomers as well as personal protection equipment (PPE) use during task performance in conjunction with urinary hexamethylene diamine (HDA) in car body repair shop workers and industrial spray painters. Personal task based inhalation samples (n = 95) were collected from six car body repair shops and five industrial painting companies using impingers with di-n-butylamine (DBA) in toluene. In parallel, dermal exposure was assessed using nitril rubber gloves. Gloves were submerged into DBA in toluene after sampling. Analysis for HDI and its oligomers was performed by LC-MS/MS. Urine samples were collected from 55 workers (n = 291) and analysed for HDA by GC-MS. Inhalation exposure was strongly associated with tasks during which aerosolisation occurs. Dermal exposure occurred during tasks that involve direct handling of paint. In car body repair shops associations were found between detectable dermal exposure and glove use (odds ratio (OR) 0.22, 95% confidence interval (CI) 0.09 to 0.57) and inhalation exposure level (OR 1.34, 95% CI 0.97 to 1.84 for a 10-fold increase). HDA in urine could be demonstrated in 36% and 10% of car body repair shop workers and industrial painting company workers respectively. In car body repair shops, the frequency of detectable HDA was significantly elevated at the end of the working day (OR 2.13, 95% CI 1.07 to 4.22 for 3-6 pm v 0-8 am). In both branches HDA was detected in urine of approximately 25% of the spray painters. In addition HDA was detected in urine of a large proportion of non-spray painters in car body repair shops. Although (spray) painting with lacquers containing isocyanate hardeners results in the highest external exposures to HDI and oligomers, workers that do not perform paint related tasks may also receive a considerable internal dose.

Potential Health Effects Associated with Dermal Exposure to Occupational Chemicals

PubMed Central

Anderson, Stacey E; Meade, B Jean

2014-01-01

There are a large number of workers in the United States, spanning a variety of occupational industries and sectors, who are potentially exposed to chemicals that can be absorbed through the skin. Occupational skin exposures can result in numerous diseases that can adversely affect an individual’s health and capacity to perform at work. In general, there are three types of chemical–skin interactions of concern: direct skin effects, immune-mediated skin effects, and systemic effects. While hundreds of chemicals (metals, epoxy and acrylic resins, rubber additives, and chemical intermediates) present in virtually every industry have been identified to cause direct and immune-mediated effects such as contact dermatitis or urticaria, less is known about the number and types of chemicals contributing to systemic effects. In an attempt to raise awareness, skin notation assignments communicate the potential for dermal absorption; however, there is a need for standardization among agencies to communicate an accurate description of occupational hazards. Studies have suggested that exposure to complex mixtures, excessive hand washing, use of hand sanitizers, high frequency of wet work, and environmental or other factors may enhance penetration and stimulate other biological responses altering the outcomes of dermal chemical exposure. Understanding the hazards of dermal exposure is essential for the proper implementation of protective measures to ensure worker safety and health. PMID:25574139

Potential health effects associated with dermal exposure to occupational chemicals.

PubMed

Anderson, Stacey E; Meade, B Jean

2014-01-01

There are a large number of workers in the United States, spanning a variety of occupational industries and sectors, who are potentially exposed to chemicals that can be absorbed through the skin. Occupational skin exposures can result in numerous diseases that can adversely affect an individual's health and capacity to perform at work. In general, there are three types of chemical-skin interactions of concern: direct skin effects, immune-mediated skin effects, and systemic effects. While hundreds of chemicals (metals, epoxy and acrylic resins, rubber additives, and chemical intermediates) present in virtually every industry have been identified to cause direct and immune-mediated effects such as contact dermatitis or urticaria, less is known about the number and types of chemicals contributing to systemic effects. In an attempt to raise awareness, skin notation assignments communicate the potential for dermal absorption; however, there is a need for standardization among agencies to communicate an accurate description of occupational hazards. Studies have suggested that exposure to complex mixtures, excessive hand washing, use of hand sanitizers, high frequency of wet work, and environmental or other factors may enhance penetration and stimulate other biological responses altering the outcomes of dermal chemical exposure. Understanding the hazards of dermal exposure is essential for the proper implementation of protective measures to ensure worker safety and health.

Assessment of dermal exposure of greenhouse workers to the pesticide bupirimate.

PubMed

Jongen, M J; Engel, R; Leenheers, L H

1992-01-01

An HPLC method was developed for estimation of dermal exposure of greenhouse workers to the pesticide bupirimate. Chromatography was performed on a cyano-modified silica column with methanol-water (6:4 by volume) containing 5 g/L ammonium sulfate as eluent. UV detection at 310 nm was used for quantitation. Dermal exposure was assessed by letting the workers wear cotton gloves and by measuring foliar dislodgable residues in the greenhouses as potential exposure. The analytical procedure was validated for measurement of bupirimate on cotton gloves and in solutions used for the estimation of foliar dislodgable residues. Gloves were extracted with methanol. Recovery of bupirimate from fortified gloves was complete. Methanol extracts with one volume of water added and solutions containing dislodgable residues were injected directly onto the HPLC system. The limit of detection was 30 micrograms/L. Between-day coefficients of variation were 7 and 4% at concentrations of 0.6 and 28 mg/L, respectively.

78 FR 76987 - Mandipropamid; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-20

... screening battery. No systemic or dermal toxicity was observed following dermal exposure for 28 days, up to... mass spectrometric detection (LC/MS/MS), is available to enforce the tolerance expression. The method...

Dermal in vitro penetration of methiocarb, paclobutrazol, and pirimicarb: effect of nonylphenolethoxylate and protective gloves.

PubMed Central

Nielsen, J B; Andersen, H R

2001-01-01

Dermal exposure has become the major route of human occupational exposure to pesticides. Detergents are used as part of formulated pesticide products and are known to change the barrier properties of human skin in vitro. However, studies on the influence of detergents as well as protective glove materials on dermal penetration of pesticides are scarce. In an experiment using in vitro static diffusion cells mounted with human skin, we evaluated the effect of nonylphenol-ethoxylate on dermal penetration of three extensively used pesticides--methiocarb, paclobutrazol, and pirimicarb--and the protection against dermal penetration offered by protective gloves made of latex or nitrile. There was a general tendency, though not statistically significant for all pesticides, for nonylphenolethoxylate to decrease the percutaneous penetration of the three pesticides. The nitrile generally offered better protection against percutaneous penetration of pesticides than did latex, but the degree of protection decreased over time and depended on the pesticides used. PMID:11266321

Annette Bunge: developing the principles in percutaneous absorption using chemical engineering principles.

PubMed

Stinchcomb, A L

2013-01-01

Annette Bunge and her research group have had the central theme of mathematically modeling the dermal absorption process. Most of the research focus has been on estimating dermal absorption for the purpose of risk assessment, for exposure scenarios in the environment and in the occupational setting. Her work is the basis for the United States Environmental Protection Agency's estimations for dermal absorption from contaminated water. It is also the basis of the dermal absorption estimates used in determining if chemicals should be assigned a 'skin notation' for potential systemic toxicity following occupational skin exposure. The work is truly translational in that it started with mathematical theory, is validated with preclinical and human experiments, and then is used in guidelines to protect human health. Her valued research has also extended into the topical drug bioavailability and bioequivalence assessment field.

Exposure related mutagens in urine of rubber workers associated with inhalable particulate and dermal exposure

PubMed Central

Vermeulen, R; Bos, R; Pertijs, J; Kromhout, H

2003-01-01

Aims: To determine the relation of the inhalation and dermal exposure routes and mutagenic activity in the urine of rubber workers (n = 105). Methods: Mutagenic activity of ambient total suspended particulate matter (TSPM), surface contamination wipes, and Sunday and weekday urine samples was assessed with S typhimurium YG1041 in the presence of a metabolic activation system. Each subject was grouped into one of two exposure categories for dermal exposure (high (≥25 revertants/cm2), low (<25 revertants/cm2)) based on the mutagenic activity detected on likely skin contact surfaces and into two airborne mutagenic exposure categories (high (≥210 revertants/m3), low (<210 revertants/m3)). The potential influence of skin aberrations and acetylation status (NAT2) on urinary mutagenicity levels was also evaluated. Results: A non-significant increase of +1605 revertants/g creatinine in urinary mutagenicity during the workweek relative to levels observed on Sunday was observed for the total population. Subsequent multivariate regression analyses, with the subjects' weekday urinary mutagenicity levels as the dependent variable, revealed associations with environmental and mainstream tobacco smoke exposure, with the level of mutagenic contamination on surfaces with which the subjects had likely contact, with the subjects' inhalable particulate exposure level, with observed mild skin aberrations, and when the subjects had a slow acetylation phenotype. Similar associations, although weaker were observed with Sunday urinary mutagenicity levels as well, except for the association with slow acetylation phenotype. Based on measured exposure levels it could be estimated that a high potential for exposure to surface contamination with mutagenic activity increased weekday urinary mutagenicity by about 62% when compared to low exposed workers, while high inhalable particulate exposure levels increased weekday urinary mutagenicity levels by about 21%. Subjects with mild skin aberrations had an additional, non-significant, increase in weekday urinary mutagenic activity compared to subjects without any skin aberrations. Discussion: Results suggest that the dermal exposure route may contribute more to the level of genotoxic compounds in urine of rubber workers than the inhalation route. Although the study was limited in size, the results warrant further investigation in the importance of and ways to effectively control the dermal exposure route in the rubber industry. PMID:12554836

Urine 1,6-Hexamethylene Diamine (HDA) Levels Among Workers Exposed to 1,6-Hexamethylene Diisocyanate (HDI)

PubMed Central

Gaines, Linda G. T.; Fent, Kenneth W.; Flack, Sheila L.; Thomasen, Jennifer M.; Ball, Louise M.; Richardson, David B.; Ding, Kai; Whittaker, Stephen G.; Nylander-french, Leena A.

2010-01-01

Urinary 1,6-hexamethylene diamine (HDA) may serve as a biomarker for systemic exposure to 1,6-hexamethylene diisocyanate (HDI) in occupationally exposed populations. However, the quantitative relationships between dermal and inhalation exposure to HDI and urine HDA levels have not been established. We measured acid-hydrolyzed urine HDA levels along with dermal and breathing-zone levels of HDI in 48 automotive spray painters. These measurements were conducted over the course of an entire workday for up to three separate workdays that were spaced approximately 1 month apart. One urine sample was collected before the start of work with HDI-containing paints and subsequent samples were collected during the workday. HDA levels varied throughout the day and ranged from nondetectable to 65.9 μg l−1 with a geometric mean and geometric standard deviation of 0.10 μg l−1 ± 6.68. Dermal exposure and inhalation exposure levels, adjusted for the type of respirator worn, were both significant predictors of urine HDA levels in the linear mixed models. Creatinine was a significant covariate when used as an independent variable along with dermal and respirator-adjusted inhalation exposure. Consequently, exposure assessment models must account for the water content of a urine sample. These findings indicate that HDA exhibits a biphasic elimination pattern, with a half-life of 2.9 h for the fast elimination phase. Our results also indicate that urine HDA level is significantly associated with systemic HDI exposure through both the skin and the lungs. We conclude that urinary HDA may be used as a biomarker of exposure to HDI, but biological monitoring should be tailored to reliably capture the intermittent exposure pattern typical in this industry. PMID:20530123

Urine 1,6-hexamethylene diamine (HDA) levels among workers exposed to 1,6-hexamethylene diisocyanate (HDI).

PubMed

Gaines, Linda G T; Fent, Kenneth W; Flack, Sheila L; Thomasen, Jennifer M; Ball, Louise M; Richardson, David B; Ding, Kai; Whittaker, Stephen G; Nylander-French, Leena A

2010-08-01

Urinary 1,6-hexamethylene diamine (HDA) may serve as a biomarker for systemic exposure to 1,6-hexamethylene diisocyanate (HDI) in occupationally exposed populations. However, the quantitative relationships between dermal and inhalation exposure to HDI and urine HDA levels have not been established. We measured acid-hydrolyzed urine HDA levels along with dermal and breathing-zone levels of HDI in 48 automotive spray painters. These measurements were conducted over the course of an entire workday for up to three separate workdays that were spaced approximately 1 month apart. One urine sample was collected before the start of work with HDI-containing paints and subsequent samples were collected during the workday. HDA levels varied throughout the day and ranged from nondetectable to 65.9 microg l(-1) with a geometric mean and geometric standard deviation of 0.10 microg l(-1) +/- 6.68. Dermal exposure and inhalation exposure levels, adjusted for the type of respirator worn, were both significant predictors of urine HDA levels in the linear mixed models. Creatinine was a significant covariate when used as an independent variable along with dermal and respirator-adjusted inhalation exposure. Consequently, exposure assessment models must account for the water content of a urine sample. These findings indicate that HDA exhibits a biphasic elimination pattern, with a half-life of 2.9 h for the fast elimination phase. Our results also indicate that urine HDA level is significantly associated with systemic HDI exposure through both the skin and the lungs. We conclude that urinary HDA may be used as a biomarker of exposure to HDI, but biological monitoring should be tailored to reliably capture the intermittent exposure pattern typical in this industry.

Dermal absorption and urinary elimination of N-methyl-2-pyrrolidone.

PubMed

Bader, Michael; Keener, Stephen A; Wrbitzky, Renate

2005-09-01

The dermal absorption of the solvent N-methyl-2-pyrrolidone (NMP) and its elimination in urine was investigated in an experimental study. Seven volunteers were exposed to 1045 mg of liquid NMP under occlusive conditions for 2 h. Urine was collected before, during and up to 72 h after the exposure and analysed for NMP by GC/MS after liquid-liquid extraction. Additionally, the remaining NMP in the pads was determined to estimate the total dermal uptake. The concentration of NMP in urine increased rapidly after beginning of the exposure up to 1 h after the exposure was completed. A peak concentration of 1,836+/-863 microg/l was observed, the half-life in urine was 3.2 h. About 0.5% of the absorbed dose was excreted metabolically unchanged. An average dermal absorption of 5.5 mg cm(-2) h(-1) was calculated. The results of this study show that the percutaneous absorption of NMP may contribute significantly to the overall uptake of the solvent, e.g. in the workplace. Therefore, a biological monitoring of NMP exposed workers is essential for occupational-medical surveillance.

Scented traces--Dermal exposure of synthetic musk fragrances in personal care products and environmental input assessment.

PubMed

Homem, Vera; Silva, Eduardo; Alves, Arminda; Santos, Lúcia

2015-11-01

Synthetic musks are organic compounds used as fragrance and fixative additives in several personal care products. Until now, little is known about their occurrence and distribution in these household commodities. However, this information is essential to perform a human dermal exposure assessment. Therefore, this study gives an overview on the levels of 12 synthetic musks in 140 personal care products from 7 different categories (body and hair wash, toilet soaps, shaving products, dentifrice products, deodorants/antiperspirants, moisturizers and perfumes). They were analysed by QuEChERS extraction followed by gas chromatography-mass spectrometry. Detection limits were found between 0.01ngg(-1) (galaxolide) and 5.00ngg(-1) (musk xylene). Higher average concentrations of total synthetic musks were detected in perfumes (5245.05μgg(-1)) and shampoos (487.67μgg(-1)) for adults. Galaxolide, exaltolide and cashmeran were the most detected compounds. Combining these results with the daily usage amounts, an average daily dermal exposure of 75.69μgkgbw(-1)day(-1) for adults and 15.54μgkgbw(-1)day(-1) for babies/children was achieved. The main contributors for adult and babies/children dermal exposure were perfumes and lotions, respectively. About 40% of the adult daily dermal exposure is related to exaltolide, 30% galaxolide, and 15% tonalide, while for babies/children 96% occurs due to exaltolide. An estimate of the amount of musks discharged "down-the-drain" into the wastewater treatment systems through the use of toiletries was also performed. An average emission per capita of 6.7mgday(-1) was determined and galaxolide and exaltolide were the predominant musks in the effluents. Copyright © 2015 Elsevier Ltd. All rights reserved.

In vitro human epidermal permeation of nicotine from electronic cigarette refill liquids and implications for dermal exposure assessment.

PubMed

Frasch, H Frederick; Barbero, Ana M

2017-11-01

Nicotine plus flavorings in a propylene glycol (PG) vehicle are the components of electronic cigarette liquids (e-liquids), which are vaporized and inhaled by the user. Dermal exposure to nicotine and e-liquids may occur among workers in mixing and filling of e-cigarettes in the manufacturing process. Inadvertent skin contact among consumers is also a concern. In vitro nicotine permeation studies using heat-separated human epidermis were performed with surrogate and two commercial e-liquids, neat and aqueous nicotine donor formulations. Steady-state fluxes (J ss ), and lag times (t lag ) were measured for each formulation. In addition, transient (4 h) exposure and finite dose (1-10 μl/cm 2 ) experiments were undertaken using one commercial e-liquid. Average J ss (μg/cm 2 /h) from formulations were: nicotine in PG (24 mg/ml): 3.97; commercial e-liquid containing menthol (25 mg/ml nicotine): 10.2; commercial e-liquid containing limonene (25 mg/ml nicotine): 23.7; neat nicotine: 175. E-liquid lag times ranged from 5 to 10 h. Absorbed fraction of nicotine from finite doses was ≈0.3 at 48 h. The data were applied to transient exposure and finite dose dermal exposure assessment models and to a simple pharmacokinetic model. Three illustrative exposure scenarios demonstrate use of the data to predict systemic uptake and plasma concentrations from dermal exposure. The data demonstrate the potential for significant nicotine absorption through skin contact with e-cigarette refill solutions and the neat nicotine used to mix them.

Comparing Urinary Biomarkers of Airborne and Dermal Exposure to Polycyclic Aromatic Compounds in Asphalt-Exposed Workers

PubMed Central

Sobus, Jon R.; McClean, Michael D.; Herrick, Robert F.; Waidyanatha, Suramya; Nylander-French, Leena A.; Kupper, Lawrence L.; Rappaport, Stephen M.

2009-01-01

When working with hot mix asphalt, road pavers are exposed to polycyclic aromatic hydrocarbons (PAHs) through the inhalation of vapors and particulate matter (PM) and through dermal contact with PM and contaminated surfaces. Several PAHs with four to six rings are potent carcinogens which reside in these particulate emissions. Since urinary biomarkers of large PAHs are rarely detectable in asphalt workers, attention has focused upon urinary levels of the more volatile and abundant two-ring and three-ring PAHs as potential biomarkers of PAH exposure. Here, we compare levels of particulate polycyclic aromatic compounds (P-PACs, a group of aromatic hydrocarbons containing PAHs and heterocyclic compounds with four or more rings) in air and dermal patch samples from 20 road pavers to the corresponding urinary levels of naphthalene (U-Nap) (two rings), phenanthrene (U-Phe) (three rings), monohydroxylated metabolites of naphthalene (OH-Nap) and phenanthrene (OH-Phe), and 1-hydroxypyrene (OH-Pyr) (four rings), the most widely used biomarker of PAH exposure. For each worker, daily breathing-zone air (n = 55) and dermal patch samples (n = 56) were collected on three consecutive workdays along with postshift, bedtime, and morning urine samples (n = 149). Measured levels of P-PACs and the urinary analytes were used to statistically model exposure–biomarker relationships while controlling for urinary creatinine, smoking status, age, body mass index, and the timing of urine sampling. Levels of OH-Phe in urine collected postshift, at bedtime, and the following morning were all significantly associated with levels of P-PACs in air and dermal patch samples. For U-Nap, U-Phe, and OH-Pyr, both air and dermal patch measurements of P-PACs were significant predictors of postshift urine levels, and dermal patch measurements were significant predictors of bedtime urine levels (all three analytes) and morning urine levels (U-Nap and OH-Pyr only). Significant effects of creatinine concentration were observed for all analytes, and modest effects of smoking status and body mass index were observed for U-Phe and OH-Pyr, respectively. Levels of OH-Nap were not associated with P-PAC measurements in air or dermal patch samples but were significantly affected by smoking status, age, day of sample collection, and urinary creatinine. We conclude that U-Nap, U-Phe, OH-Phe, and OH-Pyr can be used as biomarkers of exposure to particulate asphalt emissions, with OH-Phe being the most promising candidate. Indications that levels of U-Nap, U-Phe, and OH-Pyr were significantly associated with dermal patch measurements well into the evening after a given work shift, combined with the small ratios of within-person variance components to between-person variance components at bedtime, suggest that bedtime measurements may be useful for investigating dermal PAH exposures. PMID:19602502

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knudsen, Gabriel A., E-mail: gabriel.knudsen@nih.gov; Hughes, Michael F.; McIntosh, Katelyn L.

Tetrabromobisphenol A (TBBPA) is currently the world's highest production volume brominated flame retardant. Humans are frequently exposed to TBBPA by the dermal route. In the present study, a parallelogram approach was used to make predictions of internal dose in exposed humans. Human and rat skin samples received 100 nmol of TBBPA/cm{sup 2} skin and absorption and penetrance were determined using a flow-through in vitro system. TBBPA-derived [{sup 14}C]-radioactivity was determined at 6 h intervals in the media and at 24 h post-dosing in the skin. The human skin and media contained an average of 3.4% and 0.2% of the totalmore » dose at the terminal time point, respectively, while the rat skin and media contained 9.3% and 3.5%, respectively. In the intact rat, 14% of a dermally-administered dose of ~ 100 nmol/cm{sup 2} remained in the skin at the dosing site, with an additional 8% reaching systemic circulation by 24 h post-dosing. Relative absorption and penetrance were less (10% total) at 24 h following dermal administration of a ten-fold higher dose (~ 1000 nmol/cm{sup 2}) to rats. However, by 72 h, 70% of this dose was either absorbed into the dosing-site skin or had reached systemic circulation. It is clear from these results that TBBPA can be absorbed by the skin and dermal contact with TBBPA may represent a small but important route of exposure. Together, these in vitro data in human and rat skin and in vivo data from rats may be used to predict TBBPA absorption in humans following dermal exposure. Based on this parallelogram calculation, up to 6% of dermally applied TBBPA may be bioavailable to humans exposed to TBBPA. - Highlights: • Tetrabromobisphenol A is the brominated flame retardant with highest global production volumes. • Humans are frequently exposed to TBBPA by the dermal route, especially via contaminated dust. • Human and rat skin data were integrated using a parallelogram method to predict human absorption. • TBBPA was dermally absorbed and skin contact may represent a small but important route of exposure. • Up to 6% of dermally applied TBBPA may be bioavailable to humans exposed to TBBPA.« less

Human dermal absorption of chlorinated organophosphate flame retardants; implications for human exposure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abou-Elwafa Abdallah, Mohamed, E-mail: mae_abdallah@yahoo.co.uk; Department of Analytical Chemistry, Faculty of Pharmacy, Assiut University, 71526 Assiut; Pawar, Gopal

Tris-2-chloroethyl phosphate (TCEP), tris (1-chloro-2-propyl) phosphate (TCIPP) and tris-1,3-dichloropropyl phosphate (TDCIPP) are organophosphate flame retardants (PFRs) widely applied in a plethora of consumer products despite their carcinogenic potential. Human dermal absorption of these PFRs is investigated for the first time using human ex vivo skin and EPISKIN™ models. Results of human ex vivo skin experiments revealed 28%, 25% and 13% absorption of the applied dose (500 ng/cm{sup 2}, finite dose) of TCEP, TCIPP and TDCIPP, respectively after 24 h exposure. The EPISKIN™ model showed enhanced permeability values (i.e. weaker barrier), that were respectively 16%, 11% and 9% for TCEP, TCIPPmore » and TDCIPP compared to human ex vivo skin. However, this difference was not significant (P > 0.05). Estimated permeability constants (K{sub p}, cm/h) showed a significant negative correlation with log K{sub ow} for the studied contaminants. The effect of hand-washing on dermal absorption of PFRs was investigated. Washing reduced overall dermal absorption, albeit to varying degrees depending on the physicochemical properties of the target PFRs. Moreover, slight variations of the absorbed dose were observed upon changing the dosing solution from acetone to 20% Tween 80 in water, indicating the potential influence of the dose vehicle on the dermal absorption of PFRs. Finally, estimated dermal uptake of the studied PFRs via contact with indoor dust was higher in UK toddlers (median ΣPFRs = 36 ng/kg bw day) than adults (median ΣPFRs = 4 ng/kg bw day). More research is required to fully elucidate the toxicological implications of such exposure. - Highlights: • Human dermal absorption of PFRs was studied using human ex vivo skin and EPISKIN™. • Absorbed fractions of TCEP, TCIPP and TDCIPP were 28%, 25% and 13% of applied dose. • Permeability constants showed significant negative correlation to log K{sub ow} of PFRs. • Skin washing reduced the overall dermal absorption of target PFRs to varying degrees. • Toddlers are more exposed to PFRs via dermal contact with indoor dust than adults.« less

Estimation of intake and uptake of bisphenols and triclosan from personal care products by dermal contact.

PubMed

Lu, Shaoyou; Yu, Yuling; Ren, Lu; Zhang, Xiaolan; Liu, Guihua; Yu, Yingxin

2018-04-15

Increasing concern has been raised in respect of exposure to bisphenols and triclosan (TCS) due to their widespread use. However, little is known about their occurrence in personal care products (PCPs) or, particularly, their dermal uptake following daily application. It is therefore necessary to evaluate the human health risk of bisphenols and TCS via dermal absorption. In this study, 150 PCPs, covering 11 different categories, were collected in China. The concentrations of seven bisphenol analogues and TCS were measured, and the associated human health risks by dermal contact were estimated. High detection frequencies of TCS (46.7%) and bisphenol AF (38.7%) were found in the PCPs. The highest mean concentration of Σ 7 BPs (sum concentration of all seven bisphenols) was 77.8ngg -1 found in masks, and the highest mean concentration of TCS was 86.7ngg -1 in hand sanitizers. The bisphenol composition profiles varied among different categories. Bisphenol A and bisphenol F generally showed higher concentrations. Combining the concentrations of the target substances with the daily usage quantities of PCPs and other parameters, the total estimated dermal intakes and uptakes of Σ 7 BPs and TCS were calculated. The results showed that the former (12.1 and 1.06ng·kg -1 bw day -1 ) were markedly higher than the latter (1.21 and 9.58×10 -2 ng·kg -1 bw day -1 ), which included dermal absorption rates of the chemicals in the estimation. Although diet is the main source, and oral ingestion is the main route, for human BPA exposure, the results of the estimated dermal uptakes of BPA in the present study combined with those from a European study show that dermal contact is the main route with thermal paper being the main contributor when both unconjugated and conjugated BPA in the human body are considered. The present study also showed that exposure to BPA in PCPs following dermal contact should not be ignored. Copyright © 2017 Elsevier B.V. All rights reserved.

Absorption, distribution, metabolism and excretion of loxoprofen after dermal application of loxoprofen gel to rats.

PubMed

Sawamura, Ryoko; Kazui, Miho; Kurihara, Atsushi; Izumi, Takashi

2014-11-01

1. Loxoprofen (LX), is a prodrug of the pharmacologically active form, trans-alcohol metabolite (trans-OH form), which shows very potent analgesic effect. In this study, the pharmacokinetics and metabolism of [(14)C]LX-derived radioactivity after dermal application of [(14)C]LX gel (LX-G) to rats were evaluated. 2. The area under concentration-time curve (AUC0-∞) of radioactivity in the plasma after the dermal application was 13.6% of that of the oral administration (p < 0.05). 3. After the dermal application, the radioactivity remained in the skin and skeletal muscle at the treated site for 168 h, whereas the AUC0-168 h of the radioactivity concentration in every tissue examined except the treated site was statistically lower than that after the oral administration (p < 0.05). 4. The trans-OH form was observed at high levels in the treated skin site at 0.5 h. Metabolite profiles in plasma, non-treated skin site and urine after the dermal application were comparable with those after the oral administration. 5. Renal excretion was the main route of elimination after the dermal application. 6. In conclusion, compared to the oral administration, the dermal application of [(14)C]LX-G showed lower systemic and tissue exposure with higher exposure in the therapeutic target site. The radioactivity revealed similar metabolite profiles in both administration routes.

Allergic Potential and Immunotoxicity Induced by Topical Application of 1-Chloro-4-(Trifluoromethyl)Benzene (PCBTF) in a Murine Model

PubMed Central

Franko, Jennifer; Jackson, Laurel G.; Meade, B. Jean; Anderson, Stacey E.

2011-01-01

The purpose of the studies in this paper was to evaluate the allergic potential, immunotoxicity, and irritancy of the occupationally relevant chemical, 1-chloro-4-(trifluoromethyl)benzene, also known as parachlorobenzotrifluoride (PCBTF), following dermal exposure in a murine model. Evaluation of the sensitization potential, conducted using the local lymph node assay (LLNA) at concentrations ranging from 50% to 100%, identified a dose-dependent increase in lymphocyte proliferation with a calculated EC3 value of 53.1%. While no elevations in total or specific IgE were observed after exposure to any concentration of the chemical, significant increases in IFN-γ protein production by stimulated draining lymphoid cells were observed, indicating a T-cell-mediated response. Dermal exposure to PCBTF was not found to alter the immune response to a T-cell-dependant antigen. These results demonstrate that PCBTF has the potential to induce allergic sensitization following dermal exposure and based on LLNA results would be classified as a weak sensitizer. PMID:21747864

Operator dermal exposure and protection provided by personal protective equipment and working coveralls during mixing/loading, application and sprayer cleaning in vineyards.

PubMed

Thouvenin, Isabelle; Bouneb, Françoise; Mercier, Thierry

2017-06-01

The efficiency of a working coverall combined with personal protective equipment to protect operators against dermal exposure to plant protection products under field conditions was studied. Operators wore a non-certified water-repellent finish polyester/cotton coverall plus a certified gown during the mixing/loading and the cleaning phases. Insecticide foliar application to a vineyard was selected as the exposure scenario. The overall dermal residue levels measured in this study were in the range of data recently collected in Europe. The water-repellent finish working coverall reduced body exposure by a factor of approximately 95%. Wearing a Category III Type 3 partial body gown during mixing/loading and cleaning of the application equipment led to a further protective effect of 98.7%. The combination of a water-repellent finish working coverall and partial body protection during specific tasks provided satisfactory levels of protection and can be considered as suitable protection for the conditions of use studied.

Dermal, inhalation, and internal exposure to 1,6‐HDI and its oligomers in car body repair shop workers and industrial spray painters

PubMed Central

Pronk, A; Yu, F; Vlaanderen, J; Tielemans, E; Preller, L; Bobeldijk, I; Deddens, J A; Latza, U; Baur, X; Heederik, D

2006-01-01

Objectives To study inhalation and dermal exposure to hexamethylene diisocyanate (HDI) and its oligomers as well as personal protection equipment (PPE) use during task performance in conjunction with urinary hexamethylene diamine (HDA) in car body repair shop workers and industrial spray painters. Methods Personal task based inhalation samples (n = 95) were collected from six car body repair shops and five industrial painting companies using impingers with di‐n‐butylamine (DBA) in toluene. In parallel, dermal exposure was assessed using nitril rubber gloves. Gloves were submerged into DBA in toluene after sampling. Analysis for HDI and its oligomers was performed by LC‐MS/MS. Urine samples were collected from 55 workers (n = 291) and analysed for HDA by GC‐MS. Results Inhalation exposure was strongly associated with tasks during which aerosolisation occurs. Dermal exposure occurred during tasks that involve direct handling of paint. In car body repair shops associations were found between detectable dermal exposure and glove use (odds ratio (OR) 0.22, 95% confidence interval (CI) 0.09 to 0.57) and inhalation exposure level (OR 1.34, 95% CI 0.97 to 1.84 for a 10‐fold increase). HDA in urine could be demonstrated in 36% and 10% of car body repair shop workers and industrial painting company workers respectively. In car body repair shops, the frequency of detectable HDA was significantly elevated at the end of the working day (OR 2.13, 95% CI 1.07 to 4.22 for 3–6 pm v 0–8 am). In both branches HDA was detected in urine of ∼25% of the spray painters. In addition HDA was detected in urine of a large proportion of non‐spray painters in car body repair shops. Conclusion Although (spray) painting with lacquers containing isocyanate hardeners results in the highest external exposures to HDI and oligomers, workers that do not perform paint related tasks may also receive a considerable internal dose. PMID:16728504

Chlorpyrifos PBPK/PD model for multiple routes of exposure.

PubMed

Poet, Torka S; Timchalk, Charles; Hotchkiss, Jon A; Bartels, Michael J

2014-10-01

1. Chlorpyrifos (CPF) is an important pesticide used to control crop insects. Human Exposures to CPF will occur primarily through oral exposure to residues on foods. A physiologically based pharmacokinetic/pharmacodynamic (PBPK/PD) model has been developed that describes the relationship between oral, dermal and inhalation doses of CPF and key events in the pathway for cholinergic effects. The model was built on a prior oral model that addressed age-related changes in metabolism and physiology. This multi-route model was developed in rats and humans to validate all scenarios in a parallelogram design. 2. Critical biological effects from CPF exposure require metabolic activation to CPF oxon, and small amounts of metabolism in tissues will potentially have a great effect on pharmacokinetics and pharmacodynamic outcomes. Metabolism (bioactivation and detoxification) was therefore added in diaphragm, brain, lung and skin compartments. Pharmacokinetic data are available for controlled human exposures via the oral and dermal routes and from oral and inhalation studies in rats. The validated model was then used to determine relative dermal versus inhalation uptake from human volunteers exposed to CPF in an indoor scenario.

The utility of naphthyl-keratin adducts as biomarkers for jet-fuel exposure

PubMed Central

Kang-Sickel, Juei-Chuan C.; Butler, Mary Ann; Frame, Lynn; Serdar, Berrin; Chao, Yi-Chun E.; Egeghy, Peter; Rappaport, Stephen M.; Toennis, Christine A.; Li, Wang; Borisova, Tatyana; French, John E.; Nylander-French, Leena A.

2014-01-01

We investigated the association between biomarkers of dermal exposure, naphthyl-keratin adducts (NKA), and urine naphthalene biomarker levels in 105 workers routinely exposed to jet-fuel. A moderate correlation was observed between NKA and urine naphthalene levels (p = 0.061). The NKA, post-exposure breath naphthalene, and male gender were associated with an increase, while CYP2E1*6 DD and GSTT1-plus (++/+−) genotypes were associated with a decrease in urine naphthalene level (p < 0.0001). The NKA show great promise as biomarkers for dermal exposure to naphthalene. Further studies are warranted to characterize the relationship between NKA, other exposure biomarkers, and/or biomarkers of biological effects due to naphthalene and/or PAH exposure. PMID:21961652

The utility of naphthyl-keratin adducts as biomarkers for jet-fuel exposure.

PubMed

Kang-Sickel, Juei-Chuan C; Butler, Mary Ann; Frame, Lynn; Serdar, Berrin; Chao, Yi-Chun E; Egeghy, Peter; Rappaport, Stephen M; Toennis, Christine A; Li, Wang; Borisova, Tatyana; French, John E; Nylander-French, Leena A

2011-11-01

We investigated the association between biomarkers of dermal exposure, naphthyl-keratin adducts (NKA), and urine naphthalene biomarker levels in 105 workers routinely exposed to jet-fuel. A moderate correlation was observed between NKA and urine naphthalene levels (p = 0.061). The NKA, post-exposure breath naphthalene, and male gender were associated with an increase, while CYP2E1*6 DD and GSTT1-plus (++/+-) genotypes were associated with a decrease in urine naphthalene level (p < 0.0001). The NKA show great promise as biomarkers for dermal exposure to naphthalene. Further studies are warranted to characterize the relationship between NKA, other exposure biomarkers, and/or biomarkers of biological effects due to naphthalene and/or PAH exposure.

A new technique to assess dermal absorption of volatile chemicals in vitro by thermal gravimetric analysis.

PubMed

Rauma, Matias; Isaksson, Tina S; Johanson, Gunnar

2006-10-01

Potential health hazards of dermal exposure, variability in reported dermal absorption rates and potential losses from the skin by evaporation indicate a need for a simple, inexpensive and standardized procedure to measure dermal absorption and desorption of chemical substances. The aim of this study was to explore the possibility to measure dermal absorption and desorption of volatile chemicals using a new gravimetric technique, namely thermal gravimetric analysis (TGA), and trypsinated stratum corneum from pig. Changes in skin weight were readily detected before, during and after exposure to vapours of water, 2-propanol, methanol and toluene. The shape and height of the weight curves differed between the four chemicals, reflecting differences in diffusivity and partial pressure and skin:air partitioning, respectively. As the skin weight is highly sensitive to the partial pressure of volatile chemicals, including water, this technique requires carefully controlled conditions with respect to air flow, temperature, chemical vapour generation and humidity. This new technique may help in the assessment of dermal uptake of volatile chemicals. Only a small piece of skin is needed and skin integrity is not necessary, facilitating the use of human samples. The high resolution weight-time curves obtained may also help to elucidate the characteristics of absorption, desorption and diffusion of chemicals in skin.

Including non-dietary sources into an exposure assessment of the European Food Safety Authority: The challenge of multi-sector chemicals such as Bisphenol A.

PubMed

von Goetz, N; Pirow, R; Hart, A; Bradley, E; Poças, F; Arcella, D; Lillegard, I T L; Simoneau, C; van Engelen, J; Husoy, T; Theobald, A; Leclercq, C

2017-04-01

In the most recent risk assessment for Bisphenol A for the first time a multi-route aggregate exposure assessment was conducted by the European Food Safety Authority. This assessment includes exposure via dietary sources, and also contributions of the most important non-dietary sources. Both average and high aggregate exposure were calculated by source-to-dose modeling (forward calculation) for different age groups and compared with estimates based on urinary biomonitoring data (backward calculation). The aggregate exposure estimates obtained by forward and backward modeling are in the same order of magnitude, with forward modeling yielding higher estimates associated with larger uncertainty. Yet, only forward modeling can indicate the relative contribution of different sources. Dietary exposure, especially via canned food, appears to be the most important exposure source and, based on the central aggregate exposure estimates, contributes around 90% to internal exposure to total (conjugated plus unconjugated) BPA. Dermal exposure via thermal paper and to a lesser extent via cosmetic products may contribute around 10% for some age groups. The uncertainty around these estimates is considerable, but since after dermal absorption a first-pass metabolism of BPA by conjugation is lacking, dermal sources may be of equal or even higher toxicological relevance than dietary sources. Copyright © 2017 Elsevier Inc. All rights reserved.

Acute hydrofluoric acid exposure reported to Taiwan Poison Control Center, 1991-2010.

PubMed

Wu, M-L; Yang, C-C; Ger, J; Tsai, W-J; Deng, J-F

2014-05-01

Hydrofluoric acid (HF) is a dangerous chemical that can cause severe cutaneous burns as well as possible systemic toxicity. We retrospectively analyzed all human HF exposure cases reported to the National Poison Control Center of Taiwan between 1991 and 2010. In this 20-year survey, 324 calls were identified, with a majority of dermal exposure (84%). Occupational exposure accounted for 80% of all cases, with workers in semiconductor industry (61%), cleaning industry (15%), chemical or metal industry (13%), and other industries (11%). Electrolyte imbalances were uncommon, hypocalcemia, hypomagnesemia, and hypokalemia were recorded in 8.6%, 1.2%, and 1.5% of all cases, respectively. Most cases (64%) of dermal exposure received antidotal treatment. Treatment modalities of dermal exposure included calcium gluconate soaking, 49.8%; intravenous calcium, 20.6%; and topical use of calcium gluconate gel, 13.9%. Twenty patients (7%) received surgery. Following HF exposure, the majority of patients presented with mild (56.5%) or moderate (36.7%) toxic effects. However, four patients were severely intoxicated; two patients died of HF-related dysrhythmia and shock. Significant symptomology may occur following HF exposure, and most of the HF exposure required hospitals evaluation. Calcium gluconate soaks appear to be effective in reducing local pain and tissue damage. Hyperkalemia should not be overemphasized as a common finding in HF exposure, hypokalemia tends to occur in cases of severe HF poisoning.

Methamphetamine residue dermal transfer efficiencies from household surfaces.

PubMed

Van Dyke, Mike; Martyny, John W; Serrano, Kate A

2014-01-01

Methamphetamine contamination from illegal production operations poses a potential health concern for emergency responders, child protective services, law enforcement, and children living in contaminated structures. The objective of this study was to evaluate dermal transfer efficiencies of methamphetamine from contaminated household surfaces. These transfer efficiencies are lacking for methamphetamine, and would be beneficial for use in exposure models. Surfaces were contaminated using a simulated smoking method in a stainless steel chamber. Household surfaces were carpet, painted drywall, and linoleum. Dermal transfer efficiencies were obtained using cotton gloves for two hand conditions, dry or saliva moistened (wet). In addition, three contact scenarios were evaluated for both hand conditions: one, two, or three contacts with contaminated surfaces. Dermal transfer efficiencies were calculated for both hand conditions and used as inputs in a Stochastic Human Exposure and Dose Simulation model (SHEDS-Multimedia, Office of Research and Development, United States Environmental Protection Agency, Research Triangle Park, N.C.). Results of this study showed that average dermal transfer efficiencies of methamphetamine ranged from 11% for dry hands to 26% for wet hands. There was a significantly higher wet transfer as compared to dry transfer for all surfaces. For wet hands, dermal transfer depended on surface type with higher transfer from carpet and linoleum as compared to drywall. Based on our estimates of dermal transfer efficiency, a surface contamination clearance level of 1.5 μg/100 cm(2) may not ensure absorbed doses remain below the level associated with adverse health effects in all cases. Additional dermal transfer studies should be performed using skin surrogates that may better predict actual skin transfer.

Exploring uptake and biodistribution of polystyrene (nano)particles in zebrafish embryos at different developmental stages.

PubMed

van Pomeren, M; Brun, N R; Peijnenburg, W J G M; Vijver, M G

2017-09-01

In ecotoxicology, it is continuously questioned whether (nano)particle exposure results in particle uptake and subsequent biodistribution or if particles adsorb to the epithelial layer only. To contribute to answering this question, we investigated different uptake routes in zebrafish embryos and how they affect particle uptake into organs and within whole organisms. This is addressed by exposing three different life stages of the zebrafish embryo in order to cover the following exposure routes: via chorion and dermal exposure; dermal exposure; oral and dermal exposure. How different nanoparticle sizes affect uptake routes was assessed by using polystyrene particles of 25, 50, 250 and 700nm. In our experimental study, we showed that particle uptake in biota is restricted to oral exposure, whereas the dermal route resulted in adsorption to the epidermis and gills only. Ingestion followed by biodistribution was observed for the tested particles of 25 and 50nm. The particles spread through the body and eventually accumulated in specific organs and tissues such as the eyes. Particles larger than 50nm were predominantly adsorbed onto the intestinal tract and outer epidermis of zebrafish embryos. Embryos exposed to particles via both epidermis and intestine showed highest uptake and eventually accumulated particles in the eye, whereas uptake of particles via the chorion and epidermis resulted in marginal uptake. Organ uptake and internal distribution should be monitored more closely to provide more in depth information of the toxicity of particles. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

78 FR 3333 - Spiromesifen; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-16

... oral, dermal and inhalation routes of exposure. It was neither an eye nor dermal irritant, but showed..., alphabetically, the commodity ``Tea, dry'' to read as follows: Sec. 180.607 Spiromesifen; tolerances for residues. (a) General. (1) * * * Parts per Commodity million * * * * * Tea, dry 40 * * * * * * * * * * [FR Doc...

DERMAL AND MOUTHING TRANSFERS OF SURFACE RESIDUES MEASURED USING FLUORESCENCE IMAGING

EPA Science Inventory

To reduce the uncertainty associated with current estimates of children's exposure to pesticides by dermal contact and non-dietary ingestion, residue transfer data are required. Prior to conducting exhaustive studies, a screening study to develop and test methods for measuring...

Higher dermal exposure of cashiers to BPA and its association with DNA oxidative damage.

PubMed

Lv, Yanshan; Lu, Shaoyou; Dai, Yanyan; Rui, Caiyan; Wang, Yongjun; Zhou, Yuanxiu; Li, Yanru; Pang, Qihua; Fan, Ruifang

2017-01-01

Bisphenol A (BPA) is a widely used chemical in the production of many polycarbonate plastics, epoxy resin linings for food and beverage containers and thermal papers. Oral intakes from the contaminated diets were considered as the predominant source of BPA exposure for humans. However, due to the high levels of BPA on thermal receipts and their wide applications in our daily life, the amount of BPA be transferred to the skin after holding thermal paper should not be underestimated, particularly for cashiers. To investigate the contribution of BPA exposure levels via the dermal contact route and the relationship between BPA exposure level and oxidative DNA damage, six male volunteers were recruited and required to simulate the cashiers' work and handle the thermal receipts during the study period. Triclosan (TCS, an antimicrobial compound used widely in personal health and skin care products) was applied as a reference compound. Their urinary BPA, TCS and 8-hydroxy-2'-deoxyguanosine (8-OHdG) concentrations were determined by high performance liquid chromatography/ tandem spectrometer (LC/MS/MS). The results showed that after handling the thermal receipts, the urinary BPA concentrations of volunteers increased 3 times of those before the experimental period. But TCS levels in urine kept stable. There existed a correlation between BPA exposure and 8-OHdG (R 2 =0.237, p<0.001), but not between TCS and 8-OHdG concentrations (R 2 =0.026, p<0.777), indicating that more BPA exposure could lead to higher oxidative DNA damage. That the increases in 8-OHdG levels in urine being almost consistent with those of BPA suggested that handling thermal receipts resulted in the increasing BPA intakes and BPA exposure was correlated with DNA oxidative damage. After 48h of the end of handling thermal receipts, the urinary BPA levels did not descend to the levels before experiment, suggesting that the excretion of BPA via dermal contact was over 48h. BPA exposure through dermal contact route contributed 51.9% to 84% to urinary BPA levels with the GM ratio of 70.9% for cashiers, indicating that it might be seriously underestimated for cashiers according to the previous studies. More attentions should be paid on the exposure of BPA via dermal penetration for cashiers. Copyright © 2016 Elsevier Ltd. All rights reserved.

Levels of bisphenol-A in different paper products in Guangzhou, China, and assessment of human exposure via dermal contact.

PubMed

Fan, Ruifang; Zeng, Biyan; Liu, Xiaosu; Chen, Chao; Zhuang, Qinwei; Wang, Yongjun; Hu, Mingli; Lv, Yanshan; Li, Junnan; Zhou, Yuanxiu; Lin, Zhi Yuan William

2015-03-01

Bisphenol A (BPA) is a chemical widely used both in plastics production as a food and beverage container and in thermal papers as a color developer. Dietary consumption is the main route of human exposure to BPA, but dermal absorption through handling different papers might be underestimated or ignored. In this study, BPA in different paper products, including different types of papers, receipts and Chinese currencies, were investigated. BPA was detected in receipts (n = 87) and Chinese currencies (n = 46) with concentrations of 0.17-2.675 × 10(4) μg per g paper and 0.09-288.55 μg per g paper, respectively. Except for parchment papers (n = 3), copy papers (n = 3) and food contact papers (n = 3), BPA was measured in all of the other paper products, with levels of 0.01-6.67 μg per g paper. BPA transferred from thermal papers to common papers increased with the increasing contact pressure. Compared with that in water, the migration speed of BPA was doubled in the synthetic sweat. Washing hands could reduce BPA dermal exposure, and washing hands with lotion was the most efficient way. However, about 19-47% of BPA was still found on hands after different washing methods. Dermal absorption via handling of receipts and papers was estimated to be 36.45 ng per day for the general population and 1.54 × 10(-3) to 248.73 μg per day for a cashier. These values are below the maximum doses recommended by the U.S. Environmental Protection Agency and the European Food Safety Authority. However, due to its uncertain adverse effects on human beings, long-term BPA exposure through dermal absorption should be paid more attention, particularly for some occupational populations.

An interspecies correlation model to predict acute dermal toxicity of plant protection products to terrestrial life stages of amphibians using fish acute toxicity and bioconcentration data.

PubMed

Weltje, Lennart; Janz, Philipp; Sowig, Peter

2017-12-01

This paper presents a model to predict acute dermal toxicity of plant protection products (PPPs) to terrestrial amphibian life stages from (regulatory) fish data. By combining existing concepts, including interspecies correlation estimation (ICE), allometric relations, lethal body burden (LBB) and bioconcentration modelling, an equation was derived that predicts the amphibian median lethal dermal dose (LD 50 ) from standard acute toxicity values (96-h LC 50 ) for fish and bioconcentration factors (BCF) in fish. Where possible, fish BCF values were corrected to 5% lipid, and to parent compound. Then, BCF values were adjusted to an exposure duration of 96 h, in case steady state took longer to be achieved. The derived correlation equation is based on 32 LD 50 values from acute dermal toxicity experiments with 15 different species of anuran amphibians, comprising 15 different PPPs. The developed ICE model can be used in a screening approach to estimate the acute risk to amphibian terrestrial life stages from dermal exposures to PPPs with organic active substances. This has the potential to reduce unnecessary testing of vertebrates. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of a chemical mixture on dermal penetration of arsenic and nickel in male pig in vitro.

PubMed

Turkall, Rita M; Skowronski, Gloria A; Suh, Duck H; Abdel-Rahman, Mohamed S

2003-04-11

The effect of a chemical mixture on the dermal penetration of arsenic or nickel was assessed by applying arsenic-73 or nickel-63 alone or with the chemical mixture to dermatomed male pig skin samples in flow-through diffusion cells. The chemical mixture consisted of chloroform, phenanthrene, and toluene for arsenic penetration studies and phenol, toluene, and trichloroethylene (TCE) for nickel studies. These are predominant chemicals found at hazardous waste sites. Arsenic and nickel bind to skin after dermal exposure. Total penetration of arsenic and nickel in the chemical mixture were significantly increased by 33% and 20% compared to arsenic and nickel alone, respectively. While more radioactivity penetrated skin with chemical treatment than metal alone, significantly less radioactivity was loosely adsorbed to skin and could be easily washed off from the skin surface with soap and water. The results of this study indicate that the potential health risk from dermal exposure to arsenic or nickel is enhanced if other chemicals are present.

In vitro permeation of platinum and rhodium through Caucasian skin.

PubMed

Franken, A; Eloff, F C; Du Plessis, J; Badenhorst, C J; Jordaan, A; Du Plessis, J L

2014-12-01

During platinum group metals (PGMs) refining the possibility exists for dermal exposure to PGM salts. The dermal route has been questioned as an alternative route of exposure that could contribute to employee sensitisation, even though literature has been focused on respiratory exposure. This study aimed to investigate the in vitro permeation of platinum and rhodium through intact Caucasian skin. A donor solution of 0.3mg/ml of metal, K2PtCl4 and RhCl3 respectively, was applied to the vertical Franz diffusion cells with full thickness abdominal skin. The receptor solution was removed at various intervals during the 24h experiment, and analysed with high resolution ICP-MS. Skin was digested and analysed by ICP-OES. Results indicated cumulative permeation with prolonged exposure, with a significantly higher mass of platinum permeating after 24h when compared to rhodium. The mass of platinum retained inside the skin and the flux of platinum across the skin was significantly higher than that of rhodium. Permeated and skin retained platinum and rhodium may therefore contribute to sensitisation and indicates a health risk associated with dermal exposure in the workplace. Copyright © 2014 Elsevier Ltd. All rights reserved.

Ingestion, inhalation, and dermal exposures to chloroform and trichloroethene from tap water.

PubMed Central

Weisel, C P; Jo, W K

1996-01-01

Individuals are exposed to volatile compounds present in tap water by ingestion, inhalation, and dermal absorption. Traditional risk assessments for water often only consider ingestion exposure to toxic chemicals, even though showering has been shown to increase the body burden of certain chemicals due to inhalation exposure and dermal absorption. We collected and analyzed time-series samples of expired alveolar breath to evaluate changes in concentrations of volatile organic compounds being expired, which reflects the rate of change in the bloodstream due to expiration, metabolism, and absorption into tissues. Analysis of chloroform and trichloethene in expired breath, compounds regulated in water, was also used to determine uptake from tap water by each route (inhalation, ingestion, or absorption). Each route of exposure contributed to the total exposure of these compounds from daily water use. Further, the ingestion dose was completely metabolized before entering the bloodstream, whereas the dose from the other routes was dispersed throughout the body. Thus, differences in potential biologically effective doses depend on route, target organ, and whether the contaminant or metabolite is the biologically active agent. Images Figure 1. A Figure 1. B Figure 1. C Figure 2. A Figure 2. B PMID:8834861

Determinants of dermal exposure among Nicaraguan subsistence farmers during pesticide applications with backpack sprayers.

PubMed

Blanco, Luis E; Aragón, Aurora; Lundberg, Ingvar; Lidén, Carola; Wesseling, Catharina; Nise, Gun

2005-01-01

Identification of pesticide exposure determinants has become an issue in explaining exposure variability and improving control measures. Most studies have been conducted in industrialized countries. The aim of this study was to identify relevant dermal exposure determinants among Nicaraguan subsistence farmers. Field data on possible determinants were collected during 32 pesticide applications through observation and supplementary videorecording. A multistep reduction strategy brought down the 110 potential exposure determinants to 27 variables, which were grouped as worksite, spray equipment, working practices, clothing or hygiene practices related. Dermal exposure was quantified with a modification of Fenske's visual scoring method. Multivariate linear regression modeling within groups and across groups was performed. In the within-group analyses, work practices, spray equipment and worksite related determinants explained 52, 33 and 25% of the exposure variability, respectively. Clothing and hygiene practices were weaker determinants and did not always reduce the exposure. The final model included determinants from all groups except hygiene practices and explained 69% of the exposure variability. A less restricted model increased the explained variability to 75%. Several novel determinants were identified, including spraying on a muddy terrain, dew on plants, sealing the tank lid with a cloth and wiping sweat from the face. This study showed that a combination of observation and visual scoring techniques can provide valuable information on determinants of pesticide exposure and affected body parts under developing country conditions. The results could be used to develop job-specific questionnaires and to design training and preventive programs.

Exposure Assessment Tools by Routes - Dermal

EPA Pesticide Factsheets

EPA ExpoBox is a toolbox for exposure assessors. Its purpose is to provide a compendium of exposure assessment and risk characterization tools that will present comprehensive step-by-step guidance and links to relevant exposure assessment data bases

IN VIVO DERMAL ABSORPTION OF PYRETHROID PESTICIDES IN THE RAT

EPA Science Inventory

The potential for exposure to pyrethroid pesticides has risen recently because of their increased agricultural and residential use. The objective of this study was to examine the in vivo dermal absorption of bifenthrin, deltamethrin and cis-permethrin in the rat. Hair on...

In vivo dermal absorption of pyrethroid pesticides in the rat.

EPA Science Inventory

The potential for exposure to pyrethroid pesticides has risen recently because of their increased use. The objective of this study was to examine the in vivo dermal absorption of bifenthrin, deltamethrin and permethrin in the rat. Hair on the dorsal side of anesthetized adult m...

A pilot study to collect micro-activity data of two- to four-year-old farm labor children in Salinas Valley, California.

PubMed

Zartarian, V G; Streicker, J; Rivera, A; Cornejo, C S; Molina, S; Valadez, O F; Leckie, J O

1995-01-01

A pesticide exposure assessment pilot study was conducted in Salinas Valley, California during September, 1993. The pilot study had two main purposes: 1) to develop general methodologies for videotaping micro-activities of a population, and 2) to collect an initial database of activity patterns of two- to four-year-old farm labor children. Tools to accurately determine exposure and dose through all three pathways (dermal, ingestion, and inhalation) are needed to effectively assess and manage health risks posed by pesticides and other environmental pollutants. Eight to ten hours of videotape data were collected for each of four Mexican-American farm labor children. In addition, the researchers administered a day-after recall questionnaire to the caregivers of the children to test (for the study sample) the hypothesis that recall questionnaires are inadequate for collecting detailed information regarding dermal and hand-to-mouth exposures. The results of this study provide the first detailed set of videotape data on farm labor children, a population at high risk to pesticide exposures. In addition, this is the first project in the exposure assessment field to use direct observation videotaping for collecting micro-activity data in order to quantify dermal and ingestion exposure. The comparison of caregivers' recall of children's activities to actual videotapes from the pilot study supports the hypothesis that videotaping may greatly improve the accuracy of activity information used to compute dermal and ingestion exposures. However, as it was clear that the researchers' presence in some cases altered the activities of the subjects, further experiments need to be conducted to minimize interference of videotaping on exposure-related activities. This paper explains the selection of the study population, the methods used to implement the pilot study, and the lessons learned. While the discussion focuses on four case studies in the Mexican-American farm labor population, the data collection methods developed and the lessons learned can be applied to other populations.

Systemic exposure to PAHs and benzene in firefighters suppressing controlled structure fires.

PubMed

Fent, Kenneth W; Eisenberg, Judith; Snawder, John; Sammons, Deborah; Pleil, Joachim D; Stiegel, Matthew A; Mueller, Charles; Horn, Gavin P; Dalton, James

2014-08-01

Turnout gear provides protection against dermal exposure to contaminants during firefighting; however, the level of protection is unknown. We explored the dermal contribution to the systemic dose of polycyclic aromatic hydrocarbons (PAHs) and other aromatic hydrocarbons in firefighters during suppression and overhaul of controlled structure burns. The study was organized into two rounds, three controlled burns per round, and five firefighters per burn. The firefighters wore new or laundered turnout gear tested before each burn to ensure lack of PAH contamination. To ensure that any increase in systemic PAH levels after the burn was the result of dermal rather than inhalation exposure, the firefighters did not remove their self-contained breathing apparatus until overhaul was completed and they were >30 m upwind from the burn structure. Specimens were collected before and at intervals after the burn for biomarker analysis. Urine was analyzed for phenanthrene equivalents using enzyme-linked immunosorbent assay and a benzene metabolite (s-phenylmercapturic acid) using liquid chromatography/tandem mass spectrometry; both were adjusted by creatinine. Exhaled breath collected on thermal desorption tubes was analyzed for PAHs and other aromatic hydrocarbons using gas chromatography/mass spectrometry. We collected personal air samples during the burn and skin wipe samples (corn oil medium) on several body sites before and after the burn. The air and wipe samples were analyzed for PAHs using a liquid chromatography with photodiode array detection. We explored possible changes in external exposures or biomarkers over time and the relationships between these variables using non-parametric sign tests and Spearman tests, respectively. We found significantly elevated (P < 0.05) post-exposure breath concentrations of benzene compared with pre-exposure concentrations for both rounds. We also found significantly elevated post-exposure levels of PAHs on the neck compared with pre-exposure levels for round 1. We found statistically significant positive correlations between external exposures (i.e. personal air concentrations of PAHs) and biomarkers (i.e. change in urinary PAH metabolite levels in round 1 and change in breath concentrations of benzene in round 2). The results suggest that firefighters wearing full protective ensembles absorbed combustion products into their bodies. The PAHs most likely entered firefighters' bodies through their skin, with the neck being the primary site of exposure and absorption due to the lower level of dermal protection afforded by hoods. Aromatic hydrocarbons could have been absorbed dermally during firefighting or inhaled during the doffing of gear that was off-gassing contaminants. © The Author 2014. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Systemic Exposure to PAHs and Benzene in Firefighters Suppressing Controlled Structure Fires

PubMed Central

Fent, Kenneth W.; Eisenberg, Judith; Snawder, John; Sammons, Deborah; Pleil, Joachim D.; Stiegel, Matthew A.; Mueller, Charles; Horn, Gavin P.; Dalton, James

2014-01-01

Turnout gear provides protection against dermal exposure to contaminants during firefighting; however, the level of protection is unknown. We explored the dermal contribution to the systemic dose of polycyclic aromatic hydrocarbons (PAHs) and other aromatic hydrocarbons in firefighters during suppression and overhaul of controlled structure burns. The study was organized into two rounds, three controlled burns per round, and five firefighters per burn. The firefighters wore new or laundered turnout gear tested before each burn to ensure lack of PAH contamination. To ensure that any increase in systemic PAH levels after the burn was the result of dermal rather than inhalation exposure, the firefighters did not remove their self-contained breathing apparatus until overhaul was completed and they were >30 m upwind from the burn structure. Specimens were collected before and at intervals after the burn for biomarker analysis. Urine was analyzed for phenanthrene equivalents using enzyme-linked immunosorbent assay and a benzene metabolite (s-phenylmercapturic acid) using liquid chromatography/tandem mass spectrometry; both were adjusted by creatinine. Exhaled breath collected on thermal desorption tubes was analyzed for PAHs and other aromatic hydrocarbons using gas chromatography/mass spectrometry. We collected personal air samples during the burn and skin wipe samples (corn oil medium) on several body sites before and after the burn. The air and wipe samples were analyzed for PAHs using a liquid chromatography with photodiode array detection. We explored possible changes in external exposures or biomarkers over time and the relationships between these variables using non-parametric sign tests and Spearman tests, respectively. We found significantly elevated (P < 0.05) post-exposure breath concentrations of benzene compared with pre-exposure concentrations for both rounds. We also found significantly elevated post-exposure levels of PAHs on the neck compared with pre-exposure levels for round 1. We found statistically significant positive correlations between external exposures (i.e. personal air concentrations of PAHs) and biomarkers (i.e. change in urinary PAH metabolite levels in round 1 and change in breath concentrations of benzene in round 2). The results suggest that firefighters wearing full protective ensembles absorbed combustion products into their bodies. The PAHs most likely entered firefighters’ bodies through their skin, with the neck being the primary site of exposure and absorption due to the lower level of dermal protection afforded by hoods. Aromatic hydrocarbons could have been absorbed dermally during firefighting or inhaled during the doffing of gear that was off-gassing contaminants. PMID:24906357

Exposure to organophosphate flame retardants in spray polyurethane foam applicators: Role of dermal exposure.

PubMed

Bello, Anila; Carignan, Courtney C; Xue, Yalong; Stapleton, Heather M; Bello, Dhimiter

2018-04-01

Spray polyurethane foam (SPF) is a highly effective thermal insulation material that has seen considerable market growth in the past decade. Organophosphate flame retardants (PFRs) are added to SPF formulations to meet fire code requirements. A common flame retardant used in SPF formulations is tris 1-chloro 2-propyl phosphate (TCIPP), a suspected endocrine disruptor. Exposure monitoring efforts during SPF applications have focused primarily on the isocyanate component, a potent respiratory and dermal sensitizer. However, to our knowledge, there is no monitoring data for TCIPP. To characterize occupational exposures to TCIPP and other flame retardants during SPF insulation. Workers at four SPF insulation sites and one foam removal site (total n = 14) were recruited as part of this pilot study. Personal inhalation exposure to TCIPP was monitored with a CIP-10MI inhalable sampler and potential dermal exposure was assessed through the use of a glove dosimeter. Biomarkers of TCIPP and three other PFRs were measured in urine collected from workers pre-and post-shift. Linear mixed effect models were used to analyze associations of urinary biomarkers with inhalation and dermal exposures and paired t-tests were used to examine the difference on the means of urinary biomarkers pre-and post-shift. Chemical analysis of all species was performed with liquid chromatography-electrospray ionization tandem mass spectrometry. Geometric mean (GM) concentrations of TCIPP in personal air monitors and glove dosimeters collected from SPF applicators, 294.7 μg/m 3 and 18.8 mg/pair respectively. Overall, GM concentrations of the two TCIPP urinary biomarkers BCIPP and BCIPHIPP and (6.2 and 88.8 μg/mL) were 26-35 times higher than reported in the general population. Post-shift levels of TCIPP biomarkers were higher than pre-shift even though workers at insulation sites wore supplied air respirators, gloves and coveralls. The urinary biomarkers for the other PFRs were not elevated post shift. Concentrations of TCIPP on glove dosimeters were positively associated with post-shift urinary TCIPP biomarkers (p < 0.05) whereas concentrations in personal air samples were not. High levels of urinary biomarkers for TCIPP among SPF applicators, including post-shift, points to absorption of TCIPP during the work shift, in spite of the use of best industry exposure control practices. Dermal exposure appears to be an important, if not the primary exposure pathway for TCIPP, although inhalation or incidental ingestion of foam particles post-SPF application cannot be ruled out in this pilot study. Copyright © 2018 Elsevier Ltd. All rights reserved.

[Pollution characteristics and health risk assessment of atmospheric volatile organic compounds (VOCs) in pesticide factory].

PubMed

Tan, Bing; Wang, Tie-Yu; Pang, Bo; Zhu, Zhao-Yun; Wang, Dao-Han; Lü, Yong-Long

2013-12-01

A method for determining volatile organic compounds (VOCs) in air by summa canister collecting and gas chromatography/ mass spectroscopy detecting was adopted. Pollution condition and characteristics of VOCs were discussed in three representative pesticide factories in Zhangjiakou City, Hebei Province. Meanwhile, an internationally recognized four-step evaluation model of health risk assessment was applied to preliminarily assess the health risk caused by atmospheric VOCs in different exposure ways, inhalation and dermal exposure. Results showed that serious total VOCs pollution existed in all factories. Concentrations of n-hexane (6161.90-6910.00 microg x m(-3)), benzene (126.00-179.30 microg x m(-3)) and 1,3-butadiene (115.00-177.30 microg x m(-3)) exceeded the Chronic Inhalation Reference Concentrations recommended by USEPA, corresponding to 700, 30 and 2 microg x m(-3), respectively. Concentration of dichloromethane (724.00 microg x m(-3)) in factory B was also higher than the reference concentration (600 microg x m(-3)). Results of health risk assessment indicated that non-carcinogenic risk indexes of VOCs ranged from 1.00E-04 to 1.00E + 00 by inhalation exposure, and 1.00E-09 to 1.00E-05 by dermal exposure. Risk indexes of n-hexane and dichloromethane by inhalation exposure in all factories exceeded 1, and risk index of benzene by inhalation in factory B was also higher than 1. Carcinogenic risk indexes exposed to VOCs ranged from 1.00E-08 to 1.00E-03 by inhalation exposure and 1. oo00E -13 to 1.00E-08 by dermal exposure. Cancer risk of 1,3-butadiene by inhalation exceeded 1.0E-04, which lead to definite risk, and those of benzene by inhalation also exceeded the maximum allowable level recommended by International Commission on Radiological Protection (5.0E-05). The risks of dermal exposure presented the same trend as inhalation exposure, but the level was much lower than that of inhalation exposure. Thus, inhalation exposure of atmospheric VOCs was the dominant way of health risk in these factories.

PHYSIOLOGICALLY-BASED PHARMACOKINETIC AND PHARMACODYNAMIC (PBPK/PD) MODEL FOR PREDICTING THE DERMAL DOSE AND DISPOSITION OF ORGANOPHOSPHORUS INSECTICIDES

EPA Science Inventory

Physiologically-based pharmacokinetic/ pharmacodynamic (PBPK/PD) models are particularly suited for interpretation of cumulative risk via the dermal route for which aggregate exposure must be assessed for chemicals having a common mechanism of toxicity. To this end, a quantita...

40 CFR 721.3000 - Dicarboxylic acid monoester.

Code of Federal Regulations, 2010 CFR

2010-07-01

... prevent dermal contact for any person involved in any processing or use operation where dermal contact may... prevent contact or exposure. —Promptly remove contaminated non-imprevious clothing, wash before reuse... smoking. —Keep container closed. FIRST AID: In case of contact. EYES: Immediately flush with water for at...

Computational prediction of dermal diffusivity for large number of chemicals – challenges and applications

EPA Science Inventory

The assessment of risk from dermal exposure for thousands of chemicals, such as consumer products, due to their potential to enter the environment as contaminants is a daunting task. A strategy has been developed to integrate high-throughput technologies with toxicity, known as ...

Estimating diesel fuel exposure for a plumber repairing an underground pipe.

PubMed

Finn, Mary; Stenzel, Mark; Ramachandran, Gurumurthy

2017-04-01

We estimated the diesel fuel exposure of a plumber repairing an underground water line leak at a truck stop. The repair work was performed over three days during which the plumber spent most of his time in a pit filled with a mixture of water and diesel fuel. Thus, the plumber was exposed via both the inhalation and dermal routes. While previously asymptomatic, he was diagnosed with acute renal failure 35 days after working at this site. No measurements were available for estimating either inhalation or dermal exposures or the cumulative dose and, therefore, two different approaches were used that were based on simple models of the exposure scenario. The first approach used the ideal gas law with the vapor pressure of the diesel fuel mixture to estimate a saturation vapor concentration, while the second one used a mass balance of the petroleum hydrocarbon component of diesel fuel in conjunction with the Henry's Law constant for this mixture. These inhalation exposure estimates were then adjusted to account for the limited ventilation in a confined space. The inhalation exposure concentrations predicted when handling the water layer alone is much lower than that expected from the organic layer. This case study illustrates the large differences in inhalation exposure associated with volatile organic layers and aqueous solution containing these chemicals. The estimate of dermal exposure was negligible compared to the inhalation exposure because the skin presents a much smaller surface area of exposure to the contaminant compared to the lungs. The methodology presented here is useful for situations where little information is available for more formal mathematical exposure modeling, but where adjustments to the worst-case exposures, estimated simply, can provide reasonable exposure estimates.

Exposure assessment for a nested case-control study of lung cancer among European asphalt workers.

PubMed

Agostini, Michela; Ferro, Gilles; Olsson, Ann; Burstyn, Igor; De Vocht, Frank; Hansen, Johnni; Lassen, Christina Funch; Johansen, Christoffer; Kjaerheim, Kristina; Langard, Sverre; Stucker, Isabelle; Ahrens, Wolfgang; Behrens, Thomas; Lindbohm, Marja-Liisa; Heikkilä, Pirjo; Heederik, Dick; Portengen, Lützen; Shaham, Judith; Boffetta, Paolo; Kromhout, Hans

2010-10-01

Development of a method for retrospective assessment of exposure to bitumen fume, bitumen condensate, organic vapour, polycyclic aromatic hydrocarbons, and co-exposures to known or suspected lung carcinogens for a nested case-control study of lung cancer mortality among European asphalt workers. Company questionnaires and structured questionnaires used in interviews and industry-specific job-exposure matrices (JEMs) were elaborated and applied. Three sources of information were eventually used for exposure assessment and assignment: (i) data obtained in cohort phase, (ii) data from living subjects, next-of-kin, and fellow-workers questionnaires, and (iii) JEMs for bitumen exposure by inhalation and via skin and co-exposures to known or suspected lung carcinogens within and outside cohort companies. Inhalation and dermal exposure estimates for bitumen were adjusted for time trends, time spent in a job, and other determinants of exposure (e.g. oil gravel paving). Clothing patterns, personal protective devices, and personal hygiene were taken into consideration while estimating dermal exposure. Occupational exposures could be assessed for 433 cases and 1253 controls for relevant time periods. Only 43% of work histories were spent inside original asphalt and construction companies. A total of 95.8% of job periods in cohort companies could be coded at a more detailed level. Imputation of work time and 'hygienic behaviour' multipliers was needed for <10% of work history years. Overall, downward trends in exposure were present and differences existed between countries and companies. As expected, correlations were strongest (r > 0.7) among bitumen-related agents, while correlations between coal tar, bitumen-related agents, and established lung carcinogens were weaker (r < 0.4). A systematic and detailed approach was developed to estimate inhalation and dermal exposure for a nested case-control study among asphalt workers.

Appraisal of the sensitising potential of orally and dermally administered mercaptobenzothiazole by a biphasic protocol of the local lymph node assay.

PubMed

Ahuja, Varun; Wanner, Reinhard; Platzek, Thomas; Stahlmann, Ralf

2009-10-01

Mercaptobenzothiazole (MBT) is used while manufacturing natural rubber products. Our study deals with assessing its allergenic potential following dermal and oral routes of exposure, using a biphasic local lymph node assay (LLNA). Female Balb/c mice were treated with MBT (dermally 3, 10, 30% concentrations in DMSO; orally 1, 10, 100 mg/kg doses in corn oil) on the back (dermal study) or through oral administration (oral study) on days 1-3 followed by auricular application of 3, 10 and 30% concentrations, respectively, on days 15-17. End points determined on day 19 included ear thickness, ear punch weight, lymph node weight, lymph node cell count, and lymphocyte subpopulations (CD4+, CD8+, CD45+). After dermal application of 3% or 10% solution, a significant increase in cell count and lymph node weight along with significant decrease in CD8+ cells was observed. After initial oral administration of 1 mg/kg, we noticed a significant amplification in cell count. Following oral administration of 10 mg/kg, we observed a similar increase in cell count and lymph node weight. The results of our study show that the modified biphasic LLNA protocol can be used to study the sensitising potential of a compound also following the oral route of exposure.

Evaluation of 3D-human skin equivalents for assessment of human dermal absorption of some brominated flame retardants.

PubMed

Abdallah, Mohamed Abou-Elwafa; Pawar, Gopal; Harrad, Stuart

2015-11-01

Ethical and technical difficulties inherent to studies in human tissues are impeding assessment of the dermal bioavailability of brominated flame retardants (BFRs). This is further complicated by increasing restrictions on the use of animals in toxicity testing, and the uncertainties associated with extrapolating data from animal studies to humans due to inter-species variations. To overcome these difficulties, we evaluate 3D-human skin equivalents (3D-HSE) as a novel in vitro alternative to human and animal testing for assessment of dermal absorption of BFRs. The percutaneous penetration of hexabromocyclododecanes (HBCD) and tetrabromobisphenol-A (TBBP-A) through two commercially available 3D-HSE models was studied and compared to data obtained for human ex vivo skin according to a standard protocol. No statistically significant differences were observed between the results obtained using 3D-HSE and human ex vivo skin at two exposure levels. The absorbed dose was low (less than 7%) and was significantly correlated with log Kow of the tested BFR. Permeability coefficient values showed increasing dermal resistance to the penetration of γ-HBCD>β-HBCD>α-HBCD>TBBPA. The estimated long lag times (>30 min) suggests that frequent hand washing may reduce human exposure to HBCDs and TBBPA via dermal contact. Copyright © 2015 Elsevier Ltd. All rights reserved.

Exposure to benzene in a pooled analysis of petroleum industry case-control studies.

PubMed

Glass, D C; Schnatter, A R; Tang, G; Armstrong, T W; Rushton, L

2017-11-01

Cases of lymphohematopoietic cancer from three petroleum industry cohorts, matched to controls from the respective cohort, were pooled into single study. Average benzene exposure was quantitatively estimated in ppm for each job based on measured data from the relevant country, adjusted for the specific time period, site and job exposure characteristics and the certainty of the exposure estimate scored. The probability of dermal exposure and of peak exposure was also assessed. Before risk was examined, an exposure estimate comparison and rationalisation exercise was performed across the studies to ensure accuracy and consistency of approach. This article evaluates the final exposure estimates and their use in the risk assessments. Overall benzene exposure estimates were low: 90% of participants accumulated less than 20 ppm-years. Mean cumulative exposure was estimated as 5.15 ppm-years, mean duration was 22 years, and mean exposure intensity was 0.2 ppm. 46% of participants were allocated a peak exposure (>3 ppm at least weekly). 40% of participants had a high probability of dermal exposure (based on the relative probability of at least weekly exposure). There were differences in mean intensity of exposure, probability of peak, and/or dermal exposure associated with job category, job site, and decade of exposure. Terminal Operators handling benzene-containing products were the most highly exposed group, followed by Tanker Drivers carrying gasoline. Exposures were higher around 1940-1950 and lower in more recent decades. Overall confidence in the exposure estimates was highest for recently held jobs and for white-collar jobs. We used sensitivity analyses, which included and excluded case-sets on the basis of exposure certainty scores, to inform the risk assessment. The above analyses demonstrated that the different patterns of exposure across the three studies are largely attributable to differences in jobs, site types, and time frames rather than study. This provides reassurance that the previous rationalisation of exposures achieved inter-study consistency and that the data could be confidently pooled.

Assessment of the in vitro dermal irritation potential of cerium, silver, and titanium nanoparticles in a human skin equivalent model

EPA Science Inventory

AbstractDermal exposure to metals may res·ult in irritant contact dermatitis. This study examined the potential of metal nanoparticles to elicit irritant contact dermatitis in a human skin equivalent model (HSEM) derived from epidermal keratinocytes. These cultured cells form a m...

CHEMOMORPHIC ANALYSIS OF MALATHION IN SKIN LAYERS: IMPLICATIONS FOR THE USE OF DERMATOPHARMACOKINETIC (DPK) TAPE STRIPPING IN EXPOSURE ASSESSMENT TO PESTICIDES

EPA Science Inventory

The dermatopharmacokinetic (DPK) method of dermal tape stripping may prove to be a valuable addition to risk assessment protocols for toxic substances. To examine this possibility, the dermal penetration and absorption characteristics of [14C]-malathion in
the Sprague-Dawley...

76 FR 76309 - Isoxaflutole; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-07

...). UFL = use of a LOAEL to extrapolate a NOAEL. UFS = use of a short-term study for long-term risk..., dermal, and inhalation routes of exposure and it is not a dermal sensitizer. In long-term studies via the... offspring exhibited ocular and liver toxicities as seen in long- term studies. In the acute and subchronic...

Estimating Dermal Transfer of Copper Particles from the Surfaces of Pressure-Treated Lumber and Implications for Exposure

EPA Science Inventory

Lumber pressure-treated with micronized copper was examined for the release of copper and copper micro/nanoparticles using a surface wipe method to simulate dermal transfer. In 2003, the wood industry began replacing CCA treated lumber products for residential use with copper ba...

Dermal uptake of three brominated phenols: tetrabromobisphenol A (TBBPA), tetrabromobisphenol A bis(2,3-dibromopropyl ether) (TBBPA-BDBPE), and 2,4,6-tribromophenol (TBP).

EPA Science Inventory

Three brominated phenols, TBBPA, TBBPA-BDBPE, and TBP, were assayed to determine dermal absorption and penetrance. All three chemicals are high production volume brominated flame retardants (BFR) used in consumer products, resulting in ubiquitous human exposure. TBBPA, a reactive...

Evaluation of the irritancy and hypersensitivity potential following topical application of didecyldimethylammonium chloride

PubMed Central

Anderson, Stacey E.; Shane, Hillary; Long, Carrie; Lukomska, Ewa; Meade, B. Jean; Marshall, Nikki B.

2016-01-01

Didecyldimethylammonium chloride (DDAC) is a dialkyl-quaternary ammonium compound that is used in numerous products for its bactericidal, virucidal and fungicidal properties. There have been clinical reports of immediate and delayed hypersensitivity reactions in exposed individuals; however, the sensitization potential of DDAC has not been thoroughly investigated. The purpose of these studies was to evaluate the irritancy and sensitization potential of DDAC following dermal exposure in a murine model. DDAC induced significant irritancy (0.5 and 1%), evaluated by ear swelling in female Balb/c mice. Initial evaluation of the sensitization potential was conducted using the local lymph node assay (LLNA) at concentrations ranging from 0.0625–1%. A concentration-dependent increase in lymphocyte proliferation was observed with a calculated EC3 value of 0.17%. Dermal exposure to DDAC did not induce increased production of IgE as evaluated by phenotypic analysis of draining lymph node B-cells (IgE+B220+) and measurement of total serum IgE levels. Additional phenotypic analyses revealed significant and dose-responsive increases in the absolute number of B-cells, CD4+ T-cells, CD8+ T-cells and dendritic cells in the draining lymph nodes, along with significant increases in the percentage of B-cells (0.25% and 1% DDAC) at Day 10 following 4 days of dermal exposure. There was also a significant and dose-responsive increase in the number of activated CD44 + CD4 + and CD8+ T-cells and CD86+ B-cells and dendritic cells following exposure to all concentrations of DDAC. These results demonstrate the potential for development of irritation and hypersensitivity responses to DDAC following dermal exposure and raise concerns about the use of this chemical and other quaternary ammonium compounds that may elicit similar effects. PMID:27216637

Measurements of dermal uptake of nicotine directly from air and clothing.

PubMed

Bekö, G; Morrison, G; Weschler, C J; Koch, H M; Pälmke, C; Salthammer, T; Schripp, T; Toftum, J; Clausen, G

2017-03-01

In this preliminary study, we have investigated whether dermal uptake of nicotine directly from air or indirectly from clothing can be a meaningful exposure pathway. Two participants wearing only shorts and a third participant wearing clean cotton clothes were exposed to environmental tobacco smoke (ETS), generated by mechanically "smoking" cigarettes, for three hours in a chamber while breathing clean air from head-enveloping hoods. The average nicotine concentration (420 μg/m 3 ) was comparable to the highest levels reported for smoking sections of pubs. Urine samples were collected immediately before exposure and 60 hour post-exposure for bare-skinned participants. For the clothed participant, post-exposure urine samples were collected for 24 hour. This participant then entered the chamber for another three-hour exposure wearing a hood and clothes, including a shirt that had been exposed for five days to elevated nicotine levels. The urine samples were analyzed for nicotine and two metabolites-cotinine and 3OH-cotinine. Peak urinary cotinine and 3OH-cotinine concentrations for the bare-skinned participants were comparable to levels measured among non-smokers in hospitality environments before smoking bans. The amount of dermally absorbed nicotine for each bare-skinned participant was conservatively estimated at 570 μg, but may have been larger. For the participant wearing clean clothes, uptake was ~20 μg, and while wearing a shirt previously exposed to nicotine, uptake was ~80 μg. This study demonstrates meaningful dermal uptake of nicotine directly from air or from nicotine-exposed clothes. The findings are especially relevant for children in homes with smoking or vaping. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Dermal absorption of kerosene components in rats and the influence of its amount and area of exposure.

PubMed

Tsujino, Yoshio; Hieda, Yoko; Kimura, Kojiro; Dekio, Satoshi

2003-04-23

The influences of amount and area of dermal exposure to kerosene upon the levels of kerosene components in biological samples were examined in vivo and in vitro. Thirty-two rats were randomly divided into four groups and exposed to kerosene through the abdominal skin for 2h. The amounts (soaked in cotton) and area of kerosene exposed were 1 ml/4 cm(2) in Group I, 4 ml/4 cm(2) in Group II, 4 ml/16 cm(2) in Group III and 16 ml/64 cm(2) in Group IV. Before, then 5, 10, 20, 30, 45, 60, 90 and 120 min after exposure, 0.5 ml of blood was collected. Solid tissue samples, including the exposed skin area, were harvested at 120 min. Kerosene components were analyzed by gas chromatography/mass spectrometry. Trimethylbenzens (TMBs) that are easily absorbed kerosene components, appeared at 5-20 min. The time course changes in TMB levels in blood were significantly different between Groups I and II or Groups I and III, and almost identical between Groups II and III. Similar trends were observed in tissue samples at 120 min. High concentrations of aliphatic hydrocarbons (AHCs) were detected in the exposed skin and the AHC levels were dependent on the amount of kerosene exposed per unit area. These results suggest that (1) dermal absorption of kerosene occurs soon after dermal exposure started, (2) absorption of TMBs is influenced by the total amount of kerosene rather than area of exposure, and (3) AHCs remaining in the skin at significant levels are influenced by the amount of kerosene per unit area exposed.

Orbital implant exposure treatment with porcine dermal collagen patching.

PubMed

Alwitry, A; Burns, S J; Abercrombie, L C

2006-09-01

To present a small case series of orbital implant exposures treated with porcine dermal collagen (Permacol, Tissue Science Laboratories PLC, Aldershot, Hants, UK) patching. A retrospective chart review of three cases of orbital implant exposure treated with Permacol patching. Three cases were identified. There were 4 operative episodes of Permacol patching (one socket had two attempts at permacol patching). In all 4 cases the patch rapidly failed and melted away leaving behind the orbital implant exposure. All 3 patients required implant removal. Orbital implant exposure remains a major long-term complication of evisceration and enucleation procedures. On the basis of our experience, we would not recommend using Permacol as a non-autologous material for covering exposed Medpor (Medpor, Porex Surgical, Atlanta, Georgia, USA) orbital implants. Further study is required to fully assess the safety and efficacy profile of Permacol in socket surgery.

Repeated exposure of mouse dermal fibroblasts at a sub-cytotoxic dose of UVB leads to premature senescence: a robust model of cellular photoaging.

PubMed

Zeng, Ji-ping; Bi, Bo; Chen, Liang; Yang, Ping; Guo, Yu; Zhou, Yi-qun; Liu, Tian-yi

2014-01-01

Photoaging skin is due to accumulative effect of UV irradiation that mainly imposes its damage on dermal fibroblasts. To mimic the specific cellular responses invoked by long term effect of UVB, it is preferable to develop a photo-damaged model in vitro based on repeated UVB exposure instead of a single exposure. To develop a photo-damaged model of fibroblasts by repeated UVB exposure allowing for investigation of molecular mechanism underlying premature senescence and testing of potential anti-photoaging compounds. Mouse dermal fibroblasts (MDFs) at early passages (passages 1-3) were exposed to a series of 4 sub-cytotoxic dose of UVB. The senescent phenotypes were detected at 24 or 48h after the last irradiation including cell viability, ROS generation, mitochondrial membrane potential, cell cycle, production and degradation of extracellular matrix. Repeated exposure of UVB resulted in remarkable features of senescence. It effectively avoided the disadvantages of single dose such as induction of cell death rather than senescence, inadequate stress resulting in cellular self-rehabilitation. Our work confirms the possibility of detecting cellular machinery that mediates UVB damage to fibroblasts in vitro by repeated exposure, while the potential molecular mechanisms including cell surface receptors, protein kinase signal transduction pathways, and transcription factors remain to be further evaluated. Copyright © 2013 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

Exposure to metal-working fluids in the automobile industry and the risk of male germ cell tumours.

PubMed

Behrens, Thomas; Pohlabeln, Hermann; Mester, Birte; Langner, Ingo; Schmeisser, Nils; Ahrens, Wolfgang

2012-03-01

In a previous analysis of a case-control study of testicular cancer nested in a cohort of automobile workers, we observed an increased risk for testicular cancer among workers who had ever been involved in occupational metal-cutting tasks. We investigated whether this risk increase was due to exposure to metal-working fluids (MWF). Occupational exposure to MWF was assessed in detail using a job-specific questionnaire for metal-cutting work. We calculated ORs and associated 95% CIs individually matched for age (±2 years) and adjusted for a history of cryptorchidism by conditional logistic regression. The prevalence of exposure to MWF was 39.8% among cases and 40.1% among controls. For total germ cell tumours and seminomas we did not observe risk increases for metal-cutting tasks or occupational exposure to MWF (OR 0.95; 95% CI 0.69 to 1.32 and OR 0.88; 95% CI 0.58 to 1.35, respectively). However, dermal exposure to oil-based MWF was associated with an increased risk for non-seminomatous testicular cancer. Dermal exposure to oil-based MWF for more than 5000 h showed particularly high risk estimates (OR 4.72; 95% CI 1.48 to 15.09). Long-term dermal exposure to oil-based MWF was a risk factor for the development of non-seminomatous testicular germ cell cancer. Possible measures to reduce exposure include the introduction of engineering control measures such as venting or enclosing of machines, and enforcing the use of personal protective equipment during metal cutting.

Influence of dermal exposure to ultraviolet radiation and coal tar (polycyclic aromatic hydrocarbons) on the skin aging process.

PubMed

Borska, Lenka; Andrys, Ctirad; Krejsek, Jan; Palicka, Vladimir; Vorisek, Viktor; Hamakova, Kvetoslava; Kremlacek, Jan; Borsky, Pavel; Fiala, Zdenek

2016-03-01

Ultraviolet radiation (UVR) and crude coal tar (CCT) containing PAHs can accelerate the skin-aging process (SAP). However, UVR induces the formation of an important protective factor in SAP (vitamin D). To determine the relation of SAP to selected risks and benefits of combined dermal exposure to UVR and coal tar (PAHs). The study group consisted of patients with chronic stable plaque psoriasis and treated by Goeckerman therapy (GT; daily dermal application of UVR and 5% CCT ointment). The levels of urinary 1-hydroxypyrene (1-OHP), oxidative stress (DNA and RNA damage), genotoxic damage (chromosomal aberration in peripheral lymphocytes; ABC), 25-hydroxy-vitamin D [25(OH)D] and the PASI score were evaluated before and after GT. Intensive dermal absorption of PAHs was confirmed by increased levels of 1-OHP (p<0.01). After the therapy, we found an increased level of oxidative stress (p<0.05), an increased level of genotoxic damage (ABC; p<0.001), a high efficiency of the treatment (p<0.001) and an elevated production of 25(OH)D (p<0.01). We also found a relationship between the duration of UVR and the genotoxic damage (p<0.01), vitD (p<0.05) and the PASI score (p<0.05). Furthermore, we found a relationship between oxidative stress and 25(OH)D (p<0.05) and between genotoxic damage and the PASI score (p<0.05). Dermal exposure to UVR and coal tar (PAHs) enhances the level of oxidative stress and genotoxic damage and thus contributes to SAP. However, the exposure is very effective as a treatment and elevates the production of 25(OH)D, the protective factor in SAP. According to our results, UVR is probably a more hazardous factor in SAP. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Dermal microdialysis of inflammatory markers induced by aliphatic hydrocarbons in rats

PubMed Central

Patlolla, Ram R.; Mallampati, Ramya; Fulzele, Suniket V.; Babu, R. Jayachandra; Singh, Mandip

2010-01-01

In the present study we made an attempt to understand the skin irritation cascade of selected aliphatic hydrocarbons using microdialysis technique. Microdialysis probes were inserted into dermis in the dorsal skin of hairless rats. After 2 h of probes insertion, occlusive dermal exposure (2 h) was carried out with 230 μl of nonane, dodecane and tetradecane, using Hill top chambers®. Inflammatory biomarkers such as substance P (SP), α-melanocyte stimulating hormone (α-MSH) Interleukin 6 (IL-6) and prostaglandin E2 (PGE2) were analyzed in the dialysis samples by enzyme immunoassay (EIA). SP, α-MSH and IL6 were released in significant amounts following the dermal exposure of nonane and dodecane, whereas tetradecane did not induce any of these markers in significant amounts compared to control. Nonane increased the PGE2 levels in significant amounts within 2 h of chemical exposure compared to dodecane and tetradecane. IL-6 response was found to be slow and 2–3-fold increase in IL-6 levels was observed after 5 h following nonane and dodecane application. The magnitude of skin irritation exerted by all three chemicals was in the order of nonane ≥ dodecane ≥ tetradecane. The results demonstrate that microdialysis can be used to measure the inflammatory biomarkers in the skin irritation studies and irritation response of chemicals was quantifiable by this method. In conclusion, microdialysis was found to be an excellent tool to measure several inflammatory biomarkers as a function of time after dermal exposures with irritant chemicals. PMID:19152832

40 CFR 158.1010 - Applicator exposure-criteria for testing.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) PESTICIDE PROGRAMS DATA REQUIREMENTS FOR PESTICIDES Human Exposure § 158.1010 Applicator exposure—criteria... epidemiological or poisoning incident data indicate that adverse health effects may have resulted from handling of the pesticide. (b) Exposure criteria. (1) Dermal exposure may occur during the prescribed use. (2...

40 CFR 158.1010 - Applicator exposure-criteria for testing.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) PESTICIDE PROGRAMS DATA REQUIREMENTS FOR PESTICIDES Human Exposure § 158.1010 Applicator exposure—criteria... epidemiological or poisoning incident data indicate that adverse health effects may have resulted from handling of the pesticide. (b) Exposure criteria. (1) Dermal exposure may occur during the prescribed use. (2...

40 CFR 158.1010 - Applicator exposure-criteria for testing.

Code of Federal Regulations, 2012 CFR

2012-07-01

...) PESTICIDE PROGRAMS DATA REQUIREMENTS FOR PESTICIDES Human Exposure § 158.1010 Applicator exposure—criteria... epidemiological or poisoning incident data indicate that adverse health effects may have resulted from handling of the pesticide. (b) Exposure criteria. (1) Dermal exposure may occur during the prescribed use. (2...

40 CFR 158.1010 - Applicator exposure-criteria for testing.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) PESTICIDE PROGRAMS DATA REQUIREMENTS FOR PESTICIDES Human Exposure § 158.1010 Applicator exposure—criteria... epidemiological or poisoning incident data indicate that adverse health effects may have resulted from handling of the pesticide. (b) Exposure criteria. (1) Dermal exposure may occur during the prescribed use. (2...

40 CFR 158.1010 - Applicator exposure-criteria for testing.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) PESTICIDE PROGRAMS DATA REQUIREMENTS FOR PESTICIDES Human Exposure § 158.1010 Applicator exposure—criteria... epidemiological or poisoning incident data indicate that adverse health effects may have resulted from handling of the pesticide. (b) Exposure criteria. (1) Dermal exposure may occur during the prescribed use. (2...

MICRONUCLEUS STUDIES IN THE PERIPHERAL BLOOD AND BONE MARROW OF MICE TREATED WITH JET FUELS, JP-8 AND JET-A

EPA Science Inventory

The potential adverse effects of dermal and inhalation exposure of jet fuels are important for health hazard evaluation in humans. In an animal model, the genotoxic potential of jet fuels, JP-8 and Jet-A, was investigated. Mice were treated dermally with either a single or multip...

77 FR 23625 - Quizalofop Ethyl; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-20

... via the oral, dermal, and inhalation routes of exposure. It is not an eye or dermal irritant nor a... the correct terminology, as follows: Bean, dry to bean, dry seed; sorghum, grain to sorghum, grain... 0.05 Bean, dry, seed 0.4 Bean, succulent 0.25 Beet, sugar, molasses 0.2 Beet, sugar, roots 0.1 Beet...

Predicting dermal penetration for Expocast chemicals using in silico approaches – should dermal metabolism be considered?

EPA Science Inventory

There are thousands of consumer product chemicals to which humans may be exposed to via direct (e.g. product use) or indirect (e.g. contact with contaminated media) pathways. The US EPA has developed a research program known as ExpoCast to predict exposures to give real-world con...

EVALUATION OF CHEMICAL RELEASES AND WORKER EXPOSURES FROM FILTER PRESS OPERATIONS

EPA Science Inventory

The exposures (inhalation and dermal) and releases (air, water, solids, and process streams) associated with the filtration of industrial wastewater sludge from an electronics manufacturing plant were characterized. Chemical releases and worker exposures for a target chemical (t...

Modelling effects of chemical exposure on birds wintering in agricultural landscapes: The western burrowing owl (Athene cunicularia hypugaea) as a case study

USGS Publications Warehouse

Engelman, Catherine A.; Grant, William E.; Mora, Miguel A.; Woodin, Marc

2012-01-01

We describe an ecotoxicological model that simulates the sublethal and lethal effects of chronic, low-level, chemical exposure on birds wintering in agricultural landscapes. Previous models estimating the impact on wildlife of chemicals used in agro-ecosystems typically have not included the variety of pathways, including both dermal and oral, by which individuals are exposed. The present model contains four submodels simulating (1) foraging behavior of individual birds, (2) chemical applications to crops, (3) transfers of chemicals among soil, insects, and small mammals, and (4) transfers of chemicals to birds via ingestion and dermal exposure. We demonstrate use of the model by simulating the impacts of a variety of commonly used herbicides, insecticides, growth regulators, and defoliants on western burrowing owls (Athene cunicularia hypugaea) that winter in agricultural landscapes in southern Texas, United States. The model generated reasonable movement patterns for each chemical through soil, water, insects, and rodents, as well as into the owl via consumption and dermal absorption. Sensitivity analysis suggested model predictions were sensitive to uncertainty associated with estimates of chemical half-lives in birds, soil, and prey, sensitive to parameters associated with estimating dermal exposure, and relatively insensitive to uncertainty associated with details of chemical application procedures (timing of application, amount of drift). Nonetheless, the general trends in chemical accumulations and the relative impacts of the various chemicals were robust to these parameter changes. Simulation results suggested that insecticides posed a greater potential risk to owls of both sublethal and lethal effects than do herbicides, defoliants, and growth regulators under crop scenarios typical of southern Texas, and that use of multiple indicators, or endpoints provided a more accurate assessment of risk due to agricultural chemical exposure. The model should prove useful in helping prioritize the chemicals and transfer pathways targeted in future studies and also, as these new data become available, in assessing the relative danger to other birds of exposure to different types of agricultural chemicals.

Exposure to Carbon Nanotube Material: Assessment of Nanotube Cytotoxicity Using Human Keratinocyte Cells

NASA Technical Reports Server (NTRS)

Shvedova, Anna A.; Castranova, Vincent; Kisin, Elena R.; Schwegler-Berry, Diane; Murray, Ashley R.; Gandelsman, Vadim Z.; Maynard, Andrew; Baron, Paul

2003-01-01

Carbon nanotubes are new members of carbon allotropes similar to fullerenes and graphite. Because of their unique electrical, mechanical, and thermal properties, carbon nanotubes are important for novel applications in the electronics, aerospace, and computer industries. Exposure to graphite and carbon materials has been associated with increased incidence of skin diseases, such as carbon fiber dermatitis, hyperkeratosis, and naevi. We investigated adverse effects of single-wall carbon nanotubes (SWCNT) using a cell culture of immortalized human epidermal keratinocytes (HaCaT). After 18 h of exposure of HaCaT to SWCNT, oxidative stress and cellular toxicity were indicated by formation of free radicals, accumulation of peroxidative products, antioxidant depletion, and loss of cell viability. Exposure to SWCNT also resulted in ultrastructural and morphological changes in cultured skin cells. These data indicate that dermal exposure to unrefined SWCNT may lead to dermal toxicity due to accelerated oxidative stress in the skin of exposed workers.

Designing of mouse model: a new approach for studying sulphur mustard-induced skin lesions.

PubMed

Lomash, Vinay; Deb, Utsab; Rai, Renuka; Jadhav, Sunil E; Vijayaraghavan, R; Pant, S C

2011-08-01

This study was planned to design a mouse model for studying sulphur mustard (SM)-induced skin injury. SM was applied dermally at dose of 5 or 10 mg kg(-1) in polyethyleneglycol-300 (PEG-300) or dimethylsulphoxide (DMSO) or acetone once. The changes in body weight, organ body weight indices (OBWI) and haematological and oxidative stress parameters were investigated over a period of 3-7 days and supported by histopathological observations. Exposure to SM in PEG-300 or DMSO resulted in a significant depletion in body weight, OBWI, hepatic glutathione (GSH) and elevation in hepatic lipid peroxidation, without affecting the blood GSH and hepatic oxidised glutathione (GSSG) levels. Interestingly, no aforesaid change was observed after dermal application of SM diluted in acetone. These biochemical changes were supported by the histological observations, which revealed pronounced toxic effect and damage to liver, kidney and spleen after dermal application of SM diluted in PEG-300 or DMSO. The skin showed similar microscopic changes after dermal application of SM in all the three diluents, however; the severity of lesions was found to be time and dose dependent. It can be concluded that dermal exposure of SM diluted in acetone can be used to mimic SM-induced skin toxicity without systemic toxicity in a mouse model. Copyright © 2010 Elsevier Ltd and ISBI. All rights reserved.

US EPA'S SUPERSITES PROGRAM

EPA Science Inventory

Dermal exposure to volatile organic compounds (VOCs) in water results from environmental contamination of surface, ground-, and drinking waters. This exposure occurs both in occupational and residential settings. Compartmental models incorporating body burden measurements have ...

Approaches to Estimate Consumer Exposure under TSCA

EPA Pesticide Factsheets

CEM contains a combination of models and default parameters which are used to estimate inhalation, dermal, and oral exposures to consumer products and articles for a wide variety of product and article use categories.

Occupational exposure to pesticides, nicotine and minor psychiatric disorders among tobacco farmers in southern Brazil.

PubMed

Faria, Neice Muller Xavier; Fassa, Anaclaudia Gastal; Meucci, Rodrigo Dalke; Fiori, Nadia Spada; Miranda, Vanessa Iribarrem

2014-12-01

Exposure to pesticides has been associated with psychiatric problems among farm workers, although there is still controversy as to chemical types, intensity and forms of exposure that represent risk factors for neuropsychological problems. Furthermore, tobacco workers are exposed to dermal absorption of nicotine, although its effect on mental health has not yet been studied. To identify the prevalence of minor psychiatric disorders (MPD) among tobacco farmers and associated factors, paying special attention to pesticide and nicotine exposure. This is a cross-sectional study with a representative sample of tobacco growers, characterizing economic indicators of the farms, socio-demographic factors, lifestyle habits and occupational exposures. Multivariate analysis was performed using a hierarchical Poisson regression model. A total of 2400 tobacco farmers were assessed and MPD prevalence was 12%. MPD was higher among women (PR 1.4), workers aged 40 or over, tenants/employees (PR 1.8) and those who reported having difficulty in paying debts (PR 2.0). Low socioeconomic status was inversely associated with MPD prevalence. Tasks involving dermal exposure to pesticides showed risk varying between 35% and 71%, whereas tobacco growers on farms using organophosphates had 50% more risk of MPD than those not exposed to this kind of pesticide. The number of pesticide poisoning and green tobacco sickness episodes showed linear association with MPD. The study reinforces the evidence of the association between pesticide poisoning and mental health disorders. It also points to increased risk of MPD from low socioeconomic status, dermal pesticide exposure as well as from exposure to organophosphates. Furthermore, the study reveals intense nicotine exposure as a risk for tobacco farmers' mental health. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

Urinary DAP metabolite levels in Thai farmers and their families and exposure to pesticides from agricultural pesticide spraying.

PubMed

Hanchenlaksh, Chalalai; Povey, Andrew; O'Brien, Sarah; de Vocht, Frank

2011-08-01

We conducted a biomarker study to characterise exposure to pesticides among farmers and their families in Thailand to assess the relative importance of the dermal exposure route and to identify important factors that determine exposure levels within farmers' families. Sixteen farmers' families (eight vegetable and eight fruit farmers) participated in the study. Three morning spot urine samples were collected during a pesticide spraying week. Spot samples were grouped by individual and analysed for dialkylphosphate (DAP) metabolites and creatinine. Additional information on exposure and lifestyle was collected by means of questionnaires. Dermal exposure was assessed using a semi-quantitative observational method (DREAM). Urinary DAP levels varied 20-fold between farmers, with average (geometric mean) levels of 51.1 μg/g for vegetable and 122.2 μg/g for fruit farmers. A moderate correlation (r(s)∼0.45) was found between log(e)-transformed DREAM scores and DAP levels. Farmers' urinary metabolite levels were not correlated with those of their spouses (r(s)∼-0.30) or children (r(s)∼-0.00) collected on the same days. Detectable spouses' DAP levels were on average (geometric mean) 13.0 μg/g and those of children 7.6 μg/g. Farmers in Thailand as well as their families are exposed to pesticides in the spraying season and dermal exposure is an important route. The main route of exposure for farmers' families seems to be through transfer from the farmer to family members or contamination of the home environment, rather than family members helping or playing on the farm. Showering or washing immediately after pesticide spraying greatly reduces the potential exposure of family members to pesticide residues.

Skin analysis following dermal exposure to kerosene in rats: the effects of postmortem exposure and fire.

PubMed

Hieda, Yoko; Tsujino, Yoshio; Xue, Yuying; Takayama, Koji; Fujihara, Junko; Kimura, Kojiro; Dekio, Satoshi

2004-02-01

To evaluate the usefulness of skin analysis for the forensic examination of cases involving postmortem dermal exposure to kerosene and/or fire, an experimental study using rats was performed. Rats received dermal exposure to kerosene before or after death, and the effect of fire was determined by burning an area of exposed skin after death. Kerosene concentrations in skin and blood were determined by gas chromatography-mass spectrometry and microscopic observation was performed for skin samples. No differences were observed in skin kerosene levels between antemortem and postmortem exposure. Kerosene concentrations in mildly burned skin where the stratum corneum (SC) was retained were approximately 84% compared to those in non-burned exposed skin, whereas concentrations in severely burned skin where the SC was almost completely burned off were 28% of non-burned skin. Even in non-exposed control skin 14% of the original kerosene concentrations could be detected, which was considered to be caused by contamination during the experimental protocol combined with kerosene's property of a high affinity for the SC. These results suggest that (1) skin analysis is useful in estimating the type of petroleum product involved in crimes or accidents even for postmortem exposure, (2) whether the SC is retained or not primarily determined the kerosene levels in burned skin, and (3) attention must be paid to evaluate the results obtained from skin samples in the light of the circumstances surrounding the case.

Health Risk Assessment on Hazardous Ingredients in Household Deodorizing Products

PubMed Central

Lee, Minjin; Kim, Joo-Hyon; Lee, Daeyeop; Kim, Jaewoo; Lim, Hyunwoo; Seo, Jungkwan; Park, Young-Kwon

2018-01-01

The inhalation of a water aerosol from a humidifier containing disinfectants has led to serious lung injuries in Korea. To promote the safe use of products, the Korean government enacted regulations on the chemicals in various consumer products that could have adverse health effects. Given the concern over the potential health risks associated with the hazardous ingredients in deodorizing consumer products, 17 ingredients were analyzed and assessed according to their health risk on 3 groups by the application type in 47 deodorizing products. The risk assessment study followed a stepwise procedure (e.g., collecting toxicological information, hazard identification/exposure assessment, and screening and detailed assessment for inhalation and dermal routes). The worst-case scenario and maximum concentration determined by the product purpose and application type were used as the screening assessment. In a detailed assessment, the 75th exposure factor values were used to estimate the assumed reasonable exposure to ingredients. The exposed concentrations of seven ingredients were calculated. Due to limitation of toxicity information, butylated hydroxyl toluene for a consumer’s exposure via the dermal route only was conducted for a detailed assessment. This study showed that the assessed ingredients have no health risks at their maximum concentrations in deodorizing products. This approach can be used to establish guidelines for ingredients that may pose inhalation and dermal hazards. PMID:29652814

Ecological risk of anthropogenic pollutants to reptiles: Evaluating assumptions of sensitivity and exposure.

PubMed

Weir, Scott M; Suski, Jamie G; Salice, Christopher J

2010-12-01

A large data gap for reptile ecotoxicology still persists; therefore, ecological risk assessments of reptiles usually incorporate the use of surrogate species. This necessitates that (1) the surrogate is at least as sensitive as the target taxon and/or (2) exposures to the surrogate are greater than that of the target taxon. We evaluated these assumptions for the use of birds as surrogates for reptiles. Based on a survey of the literature, birds were more sensitive than reptiles in less than 1/4 of the chemicals investigated. Dietary and dermal exposure modeling indicated that exposure to reptiles was relatively high, particularly when the dermal route was considered. We conclude that caution is warranted in the use of avian receptors as surrogates for reptiles in ecological risk assessment and emphasize the need to better understand the magnitude and mechanism of contaminant exposure in reptiles to improve exposure and risk estimation. Copyright © 2010 Elsevier Ltd. All rights reserved.

Human exposures to tilmicosin reported to poison centres, Texas, 1998-2003.

PubMed

Forrester, Mathias B

2005-05-01

Tilmicosin, or 20-deoxo-20-(3,5-dimethylpiperidin-1-yl)-desmycosin, is a macrolide antibiotic primarily utilized in livestock. This study examined 46 human exposure calls involving tilmicosin received by Texas poison centres during 1998-2003. The majority (91%) of the calls were received from northern and central Texas. All of the cases were unintentional exposures. The most frequent route of exposure was parenteral (48%). The majority of the patients were males (80%) and adults (84%). Only 46% of the patients were managed outside of health care facilities. Some sort of adverse medical outcome was reported in 93% of parenteral exposures and 54% of other-route exposures. However, only 21% of parenteral exposures and 15% of other-route exposures involved medical outcomes that were judged to be moderate or worse. No deaths were reported. The most frequently reported clinical effects among parenteral cases were dermal (79%), while only 9% of other-route exposures had dermal effects. Cardiovascular clinical effects were observed in a single case of parenteral exposure and a single case of other-route exposure. Although the majority of cases were managed with the assistance of health care facilities, the medical outcomes were usually not serious. Outcome depended on the route of exposure.

Coverage of Deep Cutaneous Wounds Using Dermal Template in Combination with Negative-pressure Therapy and Subsequent Skin Graft

PubMed Central

Chang, Alexandre A.; Lobato, Rodolfo C.; Nakamoto, Hugo A.; Tuma, Paulo; Ferreira, Marcus C.

2014-01-01

Background: We consider the use of dermal matrix associated with a skin graft to cover deep wounds in the extremities when tendon and bone are exposed. The objective of this article was to evaluate the efficacy of covering acute deep wounds through the use of a dermal regeneration template (Integra) associated with vacuum therapy and subsequent skin grafting. Methods: Twenty patients were evaluated prospectively. All of them had acute (up to 3 weeks) deep wounds in the limbs. We consider a deep wound to be that with exposure of bone, tendon, or joint. Results: The average area of integration of the dermal regeneration template was 86.5%. There was complete integration of the skin graft over the dermal matrix in 14 patients (70%), partial integration in 5 patients (25%), and total loss in 1 case (5%). The wound has completely closed in 95% of patients. Conclusions: The use of Integra dermal template associated with negative-pressure therapy and skin grafting showed an adequate rate of resolution of deep wounds with low morbidity. PMID:25289363

Model framework for integrating multiple exposure pathways to chemicals in household cleaning products.

PubMed

Shin, H-M; McKone, T E; Bennett, D H

2017-07-01

We present a screening-level exposure-assessment method which integrates exposure from all plausible exposure pathways as a result of indoor residential use of cleaning products. The exposure pathways we considered are (i) exposure to a user during product use via inhalation and dermal, (ii) exposure to chemical residues left on clothing, (iii) exposure to all occupants from the portion released indoors during use via inhalation and dermal, and (iv) exposure to the general population due to down-the-drain disposal via inhalation and ingestion. We use consumer product volatilization models to account for the chemical fractions volatilized to air (f volatilized ) and disposed down the drain (f down-the-drain ) during product use. For each exposure pathway, we use a fate and exposure model to estimate intake rates (iR) in mg/kg/d. Overall, the contribution of the four exposure pathways to the total exposure varies by the type of cleaning activities and with chemical properties. By providing a more comprehensive exposure model and by capturing additional exposures from often-overlooked exposure pathways, our method allows us to compare the relative contribution of various exposure routes and could improve high-throughput exposure assessment for chemicals in cleaning products. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

CEM-Consumer Exposure Model Download and Install Instructions

EPA Pesticide Factsheets

CEM contains a combination of models and default parameters which are used to estimate inhalation, dermal, and oral exposures to consumer products and articles for a wide variety of product and article use categories.

Impact of Clothing on Dermal Exposure to Phthalates: Observations and Insights from Sampling Both Skin and Clothing.

PubMed

Gong, Mengyan; Weschler, Charles J; Zhang, Yinping

2016-04-19

Clothing can either retard or accelerate dermal exposure to phthalates. To investigate the impact of clothing on dermal exposure to six phthalates (DMP/DEP/DiBP/DnBP/BBzP/DEHP) in real environments, two sets of experiments have been conducted: (1) Skin wipes were collected from 11 adults to examine the phthalate levels on both bare-skin (hand/forehead) and clothing-covered body locations (arm/back/calf); (2) Five adults were asked to wear just-washed jeans for 1 day (1(st) experiment), 5 days (2(nd) experiment), and 10 days (3(rd) experiment). Phthalate levels on their legs were measured on selected days during the wearing period, and phthalate levels in the jeans were measured at the end of each experiment and again after washing. Measured phthalate levels on body locations covered by clothing were lower than those on uncovered locations, but still substantial. Dermal uptake would be underestimated by a factor of 2 to 5 if absorption through body locations covered by clothing were neglected. Phthalate levels in the jeans and on the legs increased with the wearing time. However, the levels in the jeans and on the legs were not strongly correlated, indicating that other pathways, e.g, contact with bedding or bedclothes, likely contribute to the levels on the legs. The efficiency with which laundering washing removed phthalates from the jeans increased with decreasing Kow; median values ranged from very low (<5%) for DEHP to very high (∼75%) for DMP.

Dermal bioaccessibility of flame retardants from indoor dust and the influence of topically applied cosmetics.

PubMed

Pawar, Gopal; Abdallah, Mohamed Abou-Elwafa; de Sáa, Eugenia Villaverde; Harrad, Stuart

2017-01-01

Despite extensive literature on their potential adverse health effects, there is a lack of information on human dermal exposure to organic flame retardant chemicals (FRs). This study applies an in vitro physiologically based extraction test to provide new insights into the dermal bioaccessibility of various FRs from indoor dust to synthetic sweat/sebum mixture (SSSM). The bioaccessible fractions of α-, β- and γ-hexabromocyclododecane (HBCD) and tetrabromobisphenol A (TBBPA) to 1:1 (sweat/sebum) mixture were 41%, 47%, 50% and 40%, respectively. For Tris-2-chloroethyl phosphate (TCEP), tris (1-chloro-2-propyl) phosphate (TCIPP) and tris-1,3-dichloropropyl phosphate (TDCIPP), bioaccessible fractions were 10%, 17% and 19%. Composition of the SSSM and compound-specific physicochemical properties were the major factors influencing the bioaccessibility of target FRs. Except for TBBPA, the presence of cosmetics (moisturising cream, sunscreen lotion, body spray and shower gel) had a significant effect (P<0.05) on the bioaccessibility of the studied FRs. The presence of cosmetics decreased the bioaccessibility of HBCDs from indoor dust, whereas shower gel and sunscreen lotion enhanced the bioaccessibility of target PFRs. Our bioaccessibility data were applied to estimate the internal exposure of UK adults and toddlers to the target FRs via dermal contact with dust. Our worst-case scenario exposure estimates fell far below available health-based limit values for TCEP, TCIPP and TDCIPP. However, future research may erode the margin of safety for these chemicals.

Metabolism and disposition of 2-ethylhexyl-p-methoxycinnamate following oral gavage and dermal exposure in Harlan Sprague Dawley rats and B6C3F1/N mice and in hepatocytes in vitro.

PubMed

Fennell, Timothy R; Mathews, James M; Snyder, Rodney W; Hong, Yan; Watson, Scott L; Black, Sherry R; McIntyre, Barry S; Waidyanatha, Suramya

2017-11-23

1. 2-Ethylhexyl-p-methoxycinnamate (EHMC) is commonly used as an ingredient in sunscreens, resulting in potential oral and dermal exposure in humans. 2. Clearance and metabolism of EHMC in hepatocytes and disposition and metabolism of EHMC in rodents following oral (8-800 mg/kg) intravenous (IV) (8 mg/kg) or dermal (0.8-80 mg/kg representing 0.1-10% formulation concentration) exposure to [ 14 C]EHMC were investigated in rats and mice. 3. EHMC was rapidly cleared from rat and mouse hepatocytes (half-life ≤3.16 min) and less rapidly (half-life ≤48 min) from human hepatocytes. 4. [ 14 C]EHMC was extensively absorbed and excreted primarily in urine by 72 h after oral administration to rats (65-80%) and mice (63-72%). Oral doses to rats were excreted to a lesser extent (3-8%) in feces and as CO 2 (1-4%). Radioactive residues in tissues were <1% of the dose. There were no sex or species differences in disposition in rats. 5. Following dermal application, 34-42% of an 8-mg/kg dose was absorbed in rats, and 54-62% in mice in 72-h. 6. Among numerous urinary metabolites associated with hydrolysis of the ester, two potential reproductive and developmental toxicants, 2-ethylhexanol and 2-ethylhexanoic acid were produced by metabolism of EHMC.

ARE ALL ARSENIC EXPOSURES TOXIC? SUPPORTING REGIONAL RISK ASSESSMENTS THROUGH IMPROVED ARSENIC SPECIATION METHODOLOGY

EPA Science Inventory

Arsenic exposure assessments require the evaluation of the relative contribution of both media (water, food, etc.) and routes of exposure (ingestion, inhalation, dermal). For arsenic, the important media are predominately water and food and therefore, the route of concern for ...

Improving reptile ecological risk assessment: oral and dermal toxicity of pesticides to a common lizard species (Sceloporus occidentalis).

PubMed

Weir, Scott M; Yu, Shuangying; Talent, Larry G; Maul, Jonathan D; Anderson, Todd A; Salice, Christopher J

2015-08-01

Reptiles have been understudied in ecotoxicology, which limits consideration in ecological risk assessments. The goals of the present study were 3-fold: to improve oral and dermal dosing methodologies for reptiles, to generate reptile toxicity data for pesticides, and to correlate reptile and avian toxicity. The authors first assessed the toxicity of different dosing vehicles: 100 μL of water, propylene glycol, and acetone were not toxic. The authors then assessed the oral and dermal toxicity of 4 pesticides following the up-and-down procedure. Neither brodifacoum nor chlorothalonil caused mortality at doses ≤ 1750 μg/g. Under the "neat pesticide" oral exposure, endosulfan (median lethal dose [LD50] = 9.8 μg/g) was more toxic than λ-cyhalothrin (LD50 = 916.5 μg/g). Neither chemical was toxic via dermal exposure. An acetone dosing vehicle increased λ-cyhalothrin toxicity (oral LD50 = 9.8 μg/g; dermal LD50 = 17.5 μg/g), but not endosulfan. Finally, changes in dosing method and husbandry significantly increased dermal λ-cyhalothrin LD50s, which highlights the importance of standardized methods. The authors combined data from the present study with other reptile LD50s to correlate with available avian data. When only definitive LD50s were used in the analysis, a strong correlation was found between avian and reptile toxicity. The results suggest it is possible to build predictive relationships between avian and reptile LD50s. More research is needed, however, to understand trends associated with chemical classes and modes of action. © 2015 SETAC.

MEETING IN VANCOUVER, B.C.: MICRONUCLEUS STUDIES IN THE PERIPHERAL BLOOD AND BONE MARROW OF MICE TREATED WITH JET FUELS, JP-8 AND JET-A

EPA Science Inventory

The potential adverse effects of dermal and inhalation exposure of jet fuels are important for health hazard evaluation in humans. In an animal model, the genotoxic potential of jet fuels, JP-8 and Jet-A, was investigated. Mice were treated dermally with either a single or multip...

Acute Dermal Toxicity of Trimethylolethane Trinitrate (TMETN) in Rabbits

DTIC Science & Technology

1989-07-01

attributed to dermal exposure to TMETN at the 2 ml/kg dose level. Otitis media was confirmed in rabbit 84F608 and malocclusion of the teeth was observed in...84F608 36288 F Otitis Media , Purulent, Right Ear 84F609 36289 F Cecum - Pinworms 84F610 36290 F Cecum - -pinwormis 84F612 36291 M Cecum - Pinworms 84F613

Human health risk assessment of lead, manganese and copper from scrapped car paint dust from automobile workshops in Nigeria.

PubMed

Nduka, John Kanayochukwu; Onyenezi Amuka, John Paul; Onwuka, Jude Chinedu; Udowelle, Nnaemeka Arinze; Orisakwe, Orish Ebere

2016-10-01

The economic downturn in Nigeria and Structural Adjustment Programme led to the flooding of Nigerian market with imported used automobiles. Most of these vehicles needed refurbishing and reworking. The present study is a human health risk assessment of metal exposure resulting from reworking of imported used vehicles in Nigeria. Scrap paint dusts from 56 Japanese made cars were collected from 8 different mechanic villages (workshops A-H] in Southeastern Nigeria. Scrap paints were homogenized, mixed, divided into fine particles and digested by standard method. The filtrates were assayed of lead, manganese and copper with atomic absorption spectrophotometry (AAS). Workshop B has the highest concentration of Pb (4.26 ± 0.93). Manganese in workshops A and F were (3.31 ± 0.85) and (3.04 ± 0.47) respectively and were higher than the levels from workshops C, B, D, G and H. Copper in workshop D (7.11 ± 0.21) was significantly greater than the other workshops. The highest hazard quotient (HQ) through ingestion, inhalation and dermal exposures in adults were 9.44E-05 (workshop B), 4.20E-01 (workshop B) and 1.08E-05 (workshop D) respectively. The highest values for HQ through ingestion, inhalation and dermal in children were 8.82E-04, 7.61E-01 and 2.86E-05 all in workshop B respectively. For children, the highest carcinogenic risk levels were 7.05E-08, 6.09E-05 and 2.29E-10 for ingestion, inhalation and dermal exposures respectively. In adults, the carcinogenic risk levels were 7.55E-09, 3.39E-05 and 8.67E-10 for ingestion, inhalation and dermal exposures respectively. Chronic exposure to scrap car paint dusts may be of significant public health importance in Nigeria as this may add to the body burden of some heavy metals.

Comparison of International Guidelines of Dermal Absorption Tests Used in Pesticides Exposure Assessment for Operators

PubMed Central

So, Jaehwan; Ahn, Junyoung; Lee, Tae-Hee; Park, Kyung-Hun; Paik, Min-Kyoung; Jeong, Mihye; Cho, Myung-Haing

2014-01-01

The number of farmers who have suffered from non-fatal acute pesticide poisoning has been reported to vary from 5.7% to 86.7% in South Korea since 1975. Absorption through the skin is the main route of exposure to pesticides for farmers who operate with them. Several in vitro tests using the skins of humans or animal and in vivo tests using laboratory animals are introduced for the assessment of human dermal absorption level of pesticides. The objective of this study is to evaluate and compare international guidelines and strategies of dermal absorption assessments and to propose unique approaches for applications into pesticide registration process in our situation. Until present in our situation, pesticide exposure level to operator is determined just using default value of 10 as for skin absorption ratio because of data shortage. Dermal absorption tests are requested to get exposure level of pesticides and to ultimately know the safety of pesticides for operators through the comparison with the value of AOEL. When the exposure level is higher than AOEL, the pesticide cannot be approved. We reviewed the skin absorption test guidelines recommended by OECD, EFSA and EPA. The EPA recommends assessment of skin absorption of pesticides for humans through the TPA which includes all the results of in vitro human and animal and animal in vivo skin absorption studies. OECD and EFSA, employ a tiered approach, which the requirement of further study depends on the results of the former stage study. OECD guidelines accept the analysis of pesticide level absorbed through skin without radioisotope when the recovery using the non-labeled method is within 80~120%. Various factors are reviewed in this study, including the origin of skin (gender, animal species and sites of skin), thickness, temperature and, etc., which can influence the integrity of results. PMID:25584144

Metabolism of pesticides after dermal exposure to amphibians

EPA Science Inventory

Understanding how pesticide exposure to non-target species influences toxicity is necessary to accurately assess the ecological risks these compounds pose. Aquatic, terrestrial, and arboreal amphibians are often exposed to pesticides during their agricultural application resultin...

PESTICIDE SCREENING RESULTS FROM EIGHT DAYCARE CENTERS

EPA Science Inventory

To improve assessments of children's exposures to pesticides in support of the Food Quality Protection Act, priority research and data needs include: pesticide use patterns, pesticide residue distributions, and dermal exposure assessment approaches. To address these gaps, the ...

Linking existing in vitro dermal absorption data to physicochemical properties: Contribution to the design of a weight-of-evidence approach for the safety evaluation of cosmetic ingredients with low dermal bioavailability.

PubMed

Ates, Gamze; Steinmetz, Fabian P; Doktorova, Tatyana Yordanova; Madden, Judith C; Rogiers, Vera

2016-04-01

To characterize the risk of cosmetic ingredients when threshold toxicity is assumed, often the "margin of safety" (MoS) is calculated. This uncertainty factor is based on the systemic no observable (adverse) effect level (NO(A)EL) which can be derived from in vivo repeated dose toxicity studies. As in vivo studies for the purpose of the cosmetic legislation are no longer allowed in Europe and a validated in vitro alternative is not yet available, it is no longer possible to derive a NO(A)EL value for a new cosmetic ingredient. Alternatively, cosmetic ingredients with a low dermal bioavailability might not need repeated dose data, as internal exposure will be minimal and systemic toxicity might not be an issue. This study shows the possibility of identifying compounds suspected to have a low dermal bioavailability based on their physicochemical properties (molecular weight, melting point, topological polar surface area and log P) and their in vitro dermal absorption data. Although performed on a limited number of compounds, the study suggests a strategic opportunity to support the safety assessor's reasoning to omit a MoS calculation and to focus more on local toxicity and mutagenicity/genotoxicity for ingredients for which limited systemic exposure is to be expected. Copyright © 2016 Elsevier Inc. All rights reserved.

In Silico Estimation of Skin Concentration Following the Dermal Exposure to Chemicals.

PubMed

Hatanaka, Tomomi; Yoshida, Shun; Kadhum, Wesam R; Todo, Hiroaki; Sugibayashi, Kenji

2015-12-01

To develop an in silico method based on Fick's law of diffusion to estimate the skin concentration following dermal exposure to chemicals with a wide range of lipophilicity. Permeation experiments of various chemicals were performed through rat and porcine skin. Permeation parameters, namely, permeability coefficient and partition coefficient, were obtained by the fitting of data to two-layered and one-layered diffusion models for whole and stripped skin. The mean skin concentration of chemicals during steady-state permeation was calculated using the permeation parameters and compared with the observed values. All permeation profiles could be described by the diffusion models. The estimated skin concentrations of chemicals using permeation parameters were close to the observed levels and most data fell within the 95% confidence interval for complete prediction. The permeability coefficient and partition coefficient for stripped skin were almost constant, being independent of the permeant's lipophilicity. Skin concentration following dermal exposure to various chemicals can be accurately estimated based on Fick's law of diffusion. This method should become a useful tool to assess the efficacy of topically applied drugs and cosmetic ingredients, as well as the risk of chemicals likely to cause skin disorders and diseases.

Ocular sensitization of mice by live (but not irradiated) Chlamydia trachomatis serovar A

DOE Office of Scientific and Technical Information (OSTI.GOV)

Colley, D.G.; Goodman, T.G.; Barsoum, I.S.

1986-10-01

Ocular exposure of mice to live elementary bodies of Chlamydia trachomatis serovar A results in immunological sensitization of the mice. This reactivity is manifested by the development of early (5 h) and delayed-type (24 h) dermal reactivity and serovar-specific antibody formation against either live or irradiated (100 kilorads) elementary bodies. Parallel ocular exposure of mice to irradiated elementary bodies does not result in this sensitization. The early and late dermal immune responses induced by ocular exposure to live organisms can be transferred to unexposed mice by serum and lymphoid cell transfers, respectively. It appears that successful murine ocular sensitization bymore » human C. trachomatis serovar A elementary bodies is an ability manifested by live organisms and not by inactivated but antigenic organisms.« less

Cadherin 11 Involved in Basement Membrane Damage and Dermal Changes in Melasma.

PubMed

Kim, Nan-Hyung; Choi, Soo-Hyun; Lee, Tae Ryong; Lee, Chang-Hoon; Lee, Ai-Young

2016-06-15

Basement membrane (BM) disruption and dermal changes (elastosis, collagenolysis, vascular ectasia) have been reported in melasma. Although ultraviolet (UV) irradiation can induce these changes, UV is not always necessary for melasma development. Cadherin 11 (CDH11), which is upregulated in some melasma patients, has previously been shown to stimulate melanogenesis. Because CDH11 action requires cell-cell adhesion between fibroblasts and melanocytes, BM disruption in vivo should facilitate this. The aim of this study was to examine whether CDH11 overexpression leads to BM disruption and dermal changes, independent of UV irradiation. Immunohistochemistry/immunofluorescence, real-time PCR, Western blotting, and zymography suggested that BM disruption/dermal changes and related factors were present in the hyperpigmented skin of CDH11-upregulated melasma patients and in CDH11-overexpressing fibroblasts/keratinocytes. The opposite was seen in CDH11-knockdown cells. UV irradiation of the cultured cells did not increase CDH11 expression. Collectively, these data demonstrate that CDH11 overexpression could induce BM disruption and dermal changes in melasma, regardless of UV exposure.

78 FR 22789 - Methyl Jasmonate; Exemption From the Requirement of a Tolerance

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-17

.... The acute toxicity data show virtual non-toxicity for all routes of exposure and suggest that any...) and confirmed virtual non-toxicity through the oral route of exposure. There were no observed... virtual non-toxicity through the dermal route of exposure. (MRID No. 48653902). Methyl jasmonate is...

THE US EPA'S DERMAL EXPOSURE RESEARCH PROGRAM IN SUPPORT OF THE FOOD QUALITY PROTECTION ACT

EPA Science Inventory

The Food Quality Protection Act of 1996 (FQPA) requires that children's risks to pesticide exposures be considered during the tolerance-setting process. FQPA requires exposure assessments to be conducted for all pesticides sources, not just food sources. It also requires tha...

Assessment of relevant factors and relationships concerning human dermal exposure to pesticides in greenhouse applications.

PubMed

Martínez Vidal, Jose L; Egea González, Francisco J; Garrido Frenich, Antonia; Martínez Galera, María; Aguilera, Pedro A; López Carrique, Enrique

2002-08-01

Principal component analysis (PCA) was applied to the gas chromatographic data obtained from 23 different greenhouse trials. This was used to establish which factors, including application technique (very small, small, medium and large drop-size), crop characteristics (short/tall, thin/dense) and pattern application of the operator (walking towards or away from the treated area) are relevant to the dermal exposure levels of greenhouse applicators. The results showed that the highest exposure by pesticides during field applications in greenhouses, in the climatic conditions and in the crop conditions typical of a southern European country, occurs on the lower legs and front thighs of the applicators. Similar results were obtained by hierarchical cluster analysis (HCA). Drop-size seems to be very important in determining total exposure, while height and density of crops have little influence on total exposure under the conditions of the present study. No pesticide type is a major factor in total exposure. The application of multiple regression analysis (MRA) allowed assessment of the relationships between the pesticide exposure of the less affected parts of the body with the most affected parts.

Effects of mitomycin-C on normal dermal fibroblasts.

PubMed

Chen, Theodore; Kunnavatana, Shaun S; Koch, R James

2006-04-01

To evaluate the effects of mitomycin-C on the growth and autocrine growth factor production of human dermal fibroblasts from the face. In vitro study using normal adult dermal fibroblast cell lines in a serum-free model. Cell cultures were exposed to 4 mg/mL, 0.4 mg/mL, 0.04 mg/mL, 0.004 mg/mL, and 0.0004 mg/mL concentrations of mitomycin-C solution. Cell counts were performed, and the cell-free supernatants were collected at 0, 1, 3, and 5 days after the initial exposure. Population doubling times were calculated and supernatants were quantitatively assayed for basic fibroblast growth factor (bFGF) and transforming growth factor (TGF)-beta1. Continuous exposure to mitomycin-C caused fibroblast cell death by day 7 at all tested concentrations. A 4 minute exposure to mitomycin-C at 4 mg/mL caused rapid fibroblast cell death. A 4-minute exposure to mitomycin-C at either 0.4 mg/mL or 0.04 mg/mL resulted in decreased fibroblast proliferation. A 4 minute exposure to mitomycin-C at 0.4 mg/mL resulted in a marked increase in the production of both bFGF and TGF-beta1. A clinically ideal concentration of mitomycin-C would slow fibroblast proliferation yet not cause cell death to allow for a wound healing response. Mitomycin-C 0.4 mg/mL for 4 minutes satisfies the above criteria in vitro.

Assessment of the dermal exposure to azoxystrobin among women tending cucumbers in selected Polish greenhouses after restricted entry intervals expired--the role of the protective gloves.

PubMed

Jurewicz, Joanna; Hanke, Wojciech; Sobala, Wojciech; Ligocka, Danuta

2009-01-01

The purpose of our study was to determine the level of skin contamination by azoxystrobin in a group of women tending cucumbers in a vegetable-growing greenhouse after restricted entry intervals expired. Exposure samples were assessed on two days during the spring: first entry on the day after spraying of azoxystrobin and second entry six days later. Dermal exposure was measured by using patches on the outside of clothing and sampling gloves underneath regular working gloves. Pesticide deposited on clothing patches and gloves as a substitute for skin deposition was determined by liquid chromatography and mass spectrometry (LC-MS/MS). The study has shown that workers in a Polish greenhouse are exposed to pesticides at re-entry into the greenhouse after pesticides were sprayed several days earlier. Azoxystrobin has been detected on hands, shoulders and chest. Higher levels of azoxystrobin were found on the cotton gloves of women tending the vegetables than on the patches. The levels decreased (by about 60%) on the patches and increased (by about 250%) on the cotton gloves between the two days of measurement. Women working in a vegetable-growing greenhouse and not directly engaged in the process of spraying experience a measurable dermal exposure to azoxystrobin. The protective gloves constitute a source of secondary exposure rather than protecting employees' hands from contact with the pesticide. More efficient personal protective gloves for proper protection of women working in vegetable greenhouses are needed.

Quantitative cancer risk assessment for occupational exposures to asphalt fumes during built-up roofing asphalt (BURA) operations.

PubMed

Rhomberg, Lorenz R; Mayfield, David B; Goodman, Julie E; Butler, Eric L; Nascarella, Marc A; Williams, Daniel R

2015-01-01

The International Agency for Research on Cancer qualitatively characterized occupational exposure to oxidized bitumen emissions during roofing as probably carcinogenic to humans (Group 2A). We examine chemistry, exposure, epidemiology and animal toxicity data to explore quantitative risks for roofing workers applying built-up roofing asphalt (BURA). Epidemiology studies do not consistently report elevated risks, and generally do not have sufficient exposure information or adequately control for confounders, precluding their use for dose-response analysis. Dermal carcinogenicity bioassays using mice report increased tumor incidence with single high doses. In order to quantify potential cancer risks, we develop time-to-tumor model methods [consistent with U.S. Environmental Protection Agency (EPA) dose-response analysis and mixtures guidelines] using the dose-time-response shape of concurrent exposures to benzo[a]pyrene (B[a]P) as concurrent controls (which had several exposure levels) to infer presumed parallel dose-time-response curves for BURA-fume condensate. We compare EPA relative potency factor approaches, based on observed relative potency of BURA to B[a]P in similar experiments, and direct observation of the inferred BURA dose-time-response (scaled to humans) as means for characterizing a dermal unit risk factor. We apply similar approaches to limited data on asphalt-fume inhalation and respiratory cancers in rats. We also develop a method for adjusting potency estimates for asphalts that vary in composition using measured fluorescence. Overall, the various methods indicate that cancer risks to roofers from both dermal and inhalation exposure to BURA are within a range typically deemed acceptable within regulatory frameworks. The approaches developed may be useful in assessing carcinogenic potency of other complex mixtures of polycyclic aromatic compounds.

Effects of Multiple Routes of Cadmium Exposure on the Hibernation Success of the American Toad (Bufo americanus)

USGS Publications Warehouse

James, S.M.; Little, E.E.; Semlitsch, R.D.

2004-01-01

The effects of multiple routes of cadmium exposure on juvenile American toads (Bufo americanus) were evaluated using environmentally relevant concentrations. During or after exposure, toads were individually hibernated for 172 days at approximately 4??C. The following experiments were conducted: (1) dermal exposure (hibernation in soil contaminated with up to 120 ??g Cd/ g (dry weight)); (2) injection exposure (single injection with cadmium to achieve a maximum whole-body nominal concentration of 3 ??g Cd/g (wet weight) 12 days before hibernation in uncontaminated soil); and, (3) oral exposure (feeding with mealworms containing ???16 ??g Cd/g (dry weight) for 50 days before hibernation in uncontaminated soil)., We hypothesized that sublethal levels of cadmium would become lethal during hibernation because of combined chemical and cold stress. No prehibernation mortality occurred in the injection and oral exposure studies. There was a significant treatment effect on whole-body cadmium concentration in toads orally or dermally exposed and on percent of cadmium retention in toads orally exposed. There was also a trend of increased time-to-burrowing and more toads partially buried with greater cadmium concentration in the dermal study, which indicated avoidance. In all 3 experiments, no significant differences were found among cadmium treatments in hibernation survival, percent of mass loss, or locomotor performance. However, toads fed mealworms averaging 4.7 ??g Cd/g (dry weight) had only 56% survival compared with 100% survival for controls. Although our results suggest that environmentally relevant levels of cadmium do not pose a great risk to American toads, factors such as soil type or prey species may increase cadmium bioavailability, and other amphibian species may be more sensitive to cadmium than B. americanus.

COMBINED EXPOSURE TO PYRIDOSTIGMINE BROMIDE (PB), DEET, AND PERMETHRIN WITH STRESS INCREASE BLOOD-BRAIN BARRIER (BBB) PERMEABILITY AND INHIBITS BRAIN ACETYLCHOLINESTERASE IN RATS.

EPA Science Inventory

Two groups of 15 male Sprague-Dawley rats weighing 225-250 g, were administered PB (1.3mg/kg/d, oral), DEET (40mg/kg/d, dermal), and permethrin (0.13mg/kg/d, dermal) for 28 days. Animals in one group were stressed by placing them in a Plexiglas restraint tube for 5 mins. eac...

Novel aspects of intrinsic and extrinsic aging of human skin: beneficial effects of soy extract.

PubMed

Südel, Kirstin M; Venzke, Kirsten; Mielke, Heiko; Breitenbach, Ute; Mundt, Claudia; Jaspers, Sören; Koop, Urte; Sauermann, Kirsten; Knussman-Hartig, Elke; Moll, Ingrid; Gercken, Günther; Young, Anthony R; Stäb, Franz; Wenck, Horst; Gallinat, Stefan

2005-01-01

Biochemical and structural changes of the dermal connective tissue substantially contribute to the phenotype of aging skin. To study connective tissue metabolism with respect to ultraviolet (UV) exposure, we performed an in vitro (human dermal fibroblasts) and an in vivo complementary DNA array study in combination with protein analysis in young and old volunteers. Several genes of the collagen metabolism such as Collagen I, III and VI as well as heat shock protein 47 and matrix metalloproteinase-1 are expressed differentially, indicating UV-mediated effects on collagen expression, processing and degradation. In particular, Collagen I is time and age dependently reduced after a single UV exposure in human skin in vivo. Moreover, older subjects display a lower baseline level and a shorter UV-mediated increase in hyaluronan (HA) levels. To counteract these age-dependent changes, cultured fibroblasts were treated with a specific soy extract. This treatment resulted in increased collagen and HA synthesis. In a placebo-controlled in vivo study, topical application of an isoflavone-containing emulsion significantly enhanced the number of dermal papillae per area after 2 weeks. Because the flattening of the dermal-epidermal junction is the most reproducible structural change in aged skin, this soy extract appears to rejuvenate the structure of mature skin.

Isocyanate exposure assessment combining industrial hygiene methods with biomonitoring for end users of orthopedic casting products.

PubMed

Pearson, Ronald L; Logan, Perry W; Kore, Anita M; Strom, Constance M; Brosseau, Lisa M; Kingston, Richard L

2013-07-01

Previous studies have suggested a potential risk to healthcare workers applying isocyanate-containing casts, but the authors reached their conclusions based on immunological or clinical pulmonology test results alone. We designed a study to assess potential exposure to methylene diphenyl diisocyanate (MDI) among medical personnel applying orthopedic casts using two different application methods. Air, dermal, surface, and glove permeation sampling methods were combined with urinary biomonitoring to assess the overall risk of occupational asthma to workers handling these materials. No MDI was detected in any of the personal and area air samples obtained. No glove permeation of MDI was detected. A small proportion of surface (3/45) and dermal wipe (1/60) samples were positive for MDI, but were all from inexperienced technicians. Urinary metabolites of MDI [methylenedianiline (MDA)] were detected in three of six study participants prior to both a 'dry' and 'wet' application method, five of six after the dry method, and three of six after the wet method. All MDA results were below levels noted in worker or general populations. Our conclusion is that the risk of MDI exposure is small, but unquantifiable. Because there is some potential risk of dermal exposure, medical personnel are instructed to wear a minimum of 5-mil-thick (5 mil = 0.005 inches) nitrile gloves and avoid contact to unprotected skin. This could include gauntlets, long sleeves, and/or a laboratory coat.

In Vitro Dermal Safety Assessment of Silver Nanowires after Acute Exposure: Tissue vs. Cell Models

PubMed Central

Grichine, Alexei; Rachidi, Walid; Charlet, Laurent

2018-01-01

Silver nanowires (AgNW) are attractive materials that are anticipated to be incorporated into numerous consumer products such as textiles, touchscreen display, and medical devices that could be in direct contact with skin. There are very few studies on the cellular toxicity of AgNW and no studies that have specifically evaluated the potential toxicity from dermal exposure. To address this question, we investigated the dermal toxicity after acute exposure of polymer-coated AgNW with two sizes using two models, human primary keratinocytes and human reconstructed epidermis. In keratinocytes, AgNW are rapidly and massively internalized inside cells leading to dose-dependent cytotoxicity that was not due to Ag+ release. Analysing our data with different dose metrics, we propose that the number of NW is the most appropriate dose-metric for studies of AgNW toxicity. In reconstructed epidermis, the results of a standard in vitro skin irritation assay classified AgNW as non-irritant to skin and we found no evidence of penetration into the deeper layer of the epidermis. The findings show that healthy and intact epidermis provides an effective barrier for AgNW, although the study does not address potential transport through follicles or injured skin. The combined cell and tissue model approach used here is likely to provide an important methodology for assessing the risks for skin exposure to AgNW from consumer products. PMID:29641466

In Vitro Dermal Safety Assessment of Silver Nanowires after Acute Exposure: Tissue vs. Cell Models.

PubMed

Lehmann, Sylvia G; Gilbert, Benjamin; Maffeis, Thierry Gg; Grichine, Alexei; Pignot-Paintrand, Isabelle; Clavaguera, Simon; Rachidi, Walid; Seve, Michel; Charlet, Laurent

2018-04-11

Silver nanowires (AgNW) are attractive materials that are anticipated to be incorporated into numerous consumer products such as textiles, touchscreen display, and medical devices that could be in direct contact with skin. There are very few studies on the cellular toxicity of AgNW and no studies that have specifically evaluated the potential toxicity from dermal exposure. To address this question, we investigated the dermal toxicity after acute exposure of polymer-coated AgNW with two sizes using two models, human primary keratinocytes and human reconstructed epidermis. In keratinocytes, AgNW are rapidly and massively internalized inside cells leading to dose-dependent cytotoxicity that was not due to Ag⁺ release. Analysing our data with different dose metrics, we propose that the number of NW is the most appropriate dose-metric for studies of AgNW toxicity. In reconstructed epidermis, the results of a standard in vitro skin irritation assay classified AgNW as non-irritant to skin and we found no evidence of penetration into the deeper layer of the epidermis. The findings show that healthy and intact epidermis provides an effective barrier for AgNW, although the study does not address potential transport through follicles or injured skin. The combined cell and tissue model approach used here is likely to provide an important methodology for assessing the risks for skin exposure to AgNW from consumer products.

Holding Thermal Receipt Paper and Eating Food after Using Hand Sanitizer Results in High Serum Bioactive and Urine Total Levels of Bisphenol A (BPA)

PubMed Central

Hormann, Annette M.; vom Saal, Frederick S.; Nagel, Susan C.; Stahlhut, Richard W.; Moyer, Carol L.; Ellersieck, Mark R.; Welshons, Wade V.; Toutain, Pierre-Louis; Taylor, Julia A.

2014-01-01

Bisphenol A (BPA) is an endocrine disrupting environmental contaminant used in a wide variety of products, and BPA metabolites are found in almost everyone’s urine, suggesting widespread exposure from multiple sources. Regulatory agencies estimate that virtually all BPA exposure is from food and beverage packaging. However, free BPA is applied to the outer layer of thermal receipt paper present in very high (∼20 mg BPA/g paper) quantities as a print developer. Not taken into account when considering thermal paper as a source of BPA exposure is that some commonly used hand sanitizers, as well as other skin care products, contain mixtures of dermal penetration enhancing chemicals that can increase by up to 100 fold the dermal absorption of lipophilic compounds such as BPA. We found that when men and women held thermal receipt paper immediately after using a hand sanitizer with penetration enhancing chemicals, significant free BPA was transferred to their hands and then to French fries that were eaten, and the combination of dermal and oral BPA absorption led to a rapid and dramatic average maximum increase (Cmax) in unconjugated (bioactive) BPA of ∼7 ng/mL in serum and ∼20 µg total BPA/g creatinine in urine within 90 min. The default method used by regulatory agencies to test for hazards posed by chemicals is intra-gastric gavage. For BPA this approach results in less than 1% of the administered dose being bioavailable in blood. It also ignores dermal absorption as well as sublingual absorption in the mouth that both bypass first-pass liver metabolism. The elevated levels of BPA that we observed due to holding thermal paper after using a product containing dermal penetration enhancing chemicals have been related to an increased risk for a wide range of developmental abnormalities as well as diseases in adults. PMID:25337790

Holding thermal receipt paper and eating food after using hand sanitizer results in high serum bioactive and urine total levels of bisphenol A (BPA).

PubMed

Hormann, Annette M; Vom Saal, Frederick S; Nagel, Susan C; Stahlhut, Richard W; Moyer, Carol L; Ellersieck, Mark R; Welshons, Wade V; Toutain, Pierre-Louis; Taylor, Julia A

2014-01-01

Bisphenol A (BPA) is an endocrine disrupting environmental contaminant used in a wide variety of products, and BPA metabolites are found in almost everyone's urine, suggesting widespread exposure from multiple sources. Regulatory agencies estimate that virtually all BPA exposure is from food and beverage packaging. However, free BPA is applied to the outer layer of thermal receipt paper present in very high (∼20 mg BPA/g paper) quantities as a print developer. Not taken into account when considering thermal paper as a source of BPA exposure is that some commonly used hand sanitizers, as well as other skin care products, contain mixtures of dermal penetration enhancing chemicals that can increase by up to 100 fold the dermal absorption of lipophilic compounds such as BPA. We found that when men and women held thermal receipt paper immediately after using a hand sanitizer with penetration enhancing chemicals, significant free BPA was transferred to their hands and then to French fries that were eaten, and the combination of dermal and oral BPA absorption led to a rapid and dramatic average maximum increase (Cmax) in unconjugated (bioactive) BPA of ∼7 ng/mL in serum and ∼20 µg total BPA/g creatinine in urine within 90 min. The default method used by regulatory agencies to test for hazards posed by chemicals is intra-gastric gavage. For BPA this approach results in less than 1% of the administered dose being bioavailable in blood. It also ignores dermal absorption as well as sublingual absorption in the mouth that both bypass first-pass liver metabolism. The elevated levels of BPA that we observed due to holding thermal paper after using a product containing dermal penetration enhancing chemicals have been related to an increased risk for a wide range of developmental abnormalities as well as diseases in adults.

Pharmacokinetics of loxoprofen and its active metabolite after dermal application of loxoprofen gel to rats.

PubMed

Sawamura, R; Kazui, M; Kurihara, A; Izumi, T

2015-02-01

This study was conducted to evaluate the pharmacokinetics of loxoprofen (LX) and its active metabolite (trans-OH form) after a single dermal application of LX gel (LX-G) to rats. In the skin at the treated site, generation of the trans-OH form was detected and both LX and the trans-OH form remained at high concentrations for 24 h after dermal application. Furthermore, both LX and the trans-OH form also remained in the skeletal muscle over 24 h after the single dermal application, while they eliminated rapidly after the single oral administration. The area under the curve up to the last measurable point (AUC(0-t)) for plasma concentrations of LX or the trans-OH form after dermal application of LX-G was less than 11% of that after oral administration of LX. In addition, C(max) and AUC(0-t) increased in a saturable manner while increasing the dose. Overall, these results demonstrated that the trans-OH form was generated at the treated site with the process of dermal absorption of LX and it remained at the target site for a long period with low systemic exposure compared to oral administration.

Predictive Models and Tools for Screening Chemicals under TSCA: Consumer Exposure Models 1.5

EPA Pesticide Factsheets

CEM contains a combination of models and default parameters which are used to estimate inhalation, dermal, and oral exposures to consumer products and articles for a wide variety of product and article use categories.

INVESTIGATION OF TRANSFER OF FLUORESCENT TRACERS FROM SURFACES TO SKIN

EPA Science Inventory

Under the provisions of the Food Quality Protection Act (FQPA), aggregate exposure assessments must be conducted for pesticides proposed for registration. Many aspects of dermal exposure assessment remain poorly quantified. For purposes of assessing surface-to-skin transfers ...

76 FR 71346 - Public Meeting and Request for Information: Carcinogen and Recommended Exposure Limit (REL...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-17

... experimental mammalian species as the result of any oral, respiratory or dermal exposure, or any other exposure... contrast, other organizations, such as the International Agency for Research on Cancer (IARC) and the... and quicker means of classifying chemicals. Qualitative and semi- quantitative approaches such as...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jeong, Sang Hoon; Kim, Jae Hwan; Yi, Sang Min

Quantum dots (QDs) are rapidly emerging as an important class of nanoparticles (NPs) with potential applications in medicine. However, little is known about penetration of QDs through human skin. This study investigated skin penetration of QDs in both in vivo and in vitro human skin. Using the tape stripping method, this study demonstrates for the first time that QDs can actually penetrate through the stratum corneum (SC) of human skin. Transmission electron microscope (TEM) and energy diverse X-ray (EDX) analysis showed accumulation of QDs in the SC of a human skin equivalent model (HSEM) after dermal exposure to QDs. Thesemore » findings suggest possible transdermal absorption of QDs after dermal exposure over a relatively long period of time.« less

Concepts of skin protection: considerations for the evaluation and terminology of the performance of skin protective equipment.

PubMed

Brouwer, Derk H; Aitken, Robert J; Oppl, Reinhard; Cherrie, John W

2005-09-01

This article proposes a common language for better understanding processes involved in dermal exposure and skin protection. A conceptual model has been developed that systematically describes the transport of agent mass from sources, eventually resulting in "loading" of the skin surface or the skin contaminant layer. In view of a harmonized glossary of exposure terminology this is considered the exposure surface. Loading is defined as agent mass present in this layer divided by the exposure surface area. Skin protective equipment (SPE) is meant to reduce uptake, that is, an agent crosses the absorption barrier of the skin, by intervening in the processes of loading the exposure surface; however, the design of the equipment may fail to cover skin surface entirely. In addition, part of the mass intercepted by the SPE may reach the skin surface either by permeation, penetration, or by transfer when touching the contaminated exterior of the SPE. Evaluation of SPE performance has earlier focused on chemical resistance performance testing for permeation, penetration, or degradation of SPE-materials. In use-scenario practice, however, all processes will occur concurrently. Thus, SPE field performance evaluation including user-SPE interaction complementary to material testing is warranted. Results of laboratory testing for SPE-materials are reported as substance-specific breakthrough times and permeation rates. SPE field performance should be evaluated for reduction of either uptake or parameters that reflect the outcome of dermal exposure. Ideally, this should be based on the results of intervention-type workplace studies, for (e.g., assessment of exposure loading). The level of reduction can be expressed as a protection factor (ratio without/with SPE) for different parameters of dermal exposure or uptake. It is concluded that for evaluation of SPE-type performance, generic protection factors can be derived for substance-independent processes (e.g., reduction of exposure loading) but not for substance-specific reduction of uptake.

Influence of tap water quality and household water use activities on indoor air and internal dose levels of trihalomethanes.

PubMed

Nuckols, John R; Ashley, David L; Lyu, Christopher; Gordon, Sydney M; Hinckley, Alison F; Singer, Philip

2005-07-01

Individual exposure to trihalomethanes (THMs) in tap water can occur through ingestion, inhalation, or dermal exposure. Studies indicate that activities associated with inhaled or dermal exposure routes result in a greater increase in blood THM concentration than does ingestion. We measured blood and exhaled air concentrations of THM as biomarkers of exposure to participants conducting 14 common household water use activities, including ingestion of hot and cold tap water beverages, showering, clothes washing, hand washing, bathing, dish washing, and indirect shower exposure. We conducted our study at a single residence in each of two water utility service areas, one with relatively high and the other low total THM in the residence tap water. To maintain a consistent exposure environment for seven participants, we controlled water use activities, exposure time, air exchange, water flow and temperature, and nonstudy THM sources to the indoor air. We collected reference samples for water supply and air (pre-water use activity), as well as tap water and ambient air samples. We collected blood samples before and after each activity and exhaled breath samples at baseline and post-activity. All hot water use activities yielded a 2-fold increase in blood or breath THM concentrations for at least one individual. The greatest observed increase in blood and exhaled breath THM concentration in any participant was due to showering (direct and indirect), bathing, and hand dishwashing. Average increase in blood THM concentration ranged from 57 to 358 pg/mL due to these activities. More research is needed to determine whether acute and frequent exposures to THM at these concentrations have public health implications. Further research is also needed in designing epidemiologic studies that minimize data collection burden yet maximize accuracy in classification of dermal and inhalation THM exposure during hot water use activities.

Influence of Tap Water Quality and Household Water Use Activities on Indoor Air and Internal Dose Levels of Trihalomethanes

PubMed Central

Nuckols, John R.; Ashley, David L.; Lyu, Christopher; Gordon, Sydney M.; Hinckley, Alison F.; Singer, Philip

2005-01-01

Individual exposure to trihalomethanes (THMs) in tap water can occur through ingestion, inhalation, or dermal exposure. Studies indicate that activities associated with inhaled or dermal exposure routes result in a greater increase in blood THM concentration than does ingestion. We measured blood and exhaled air concentrations of THM as biomarkers of exposure to participants conducting 14 common household water use activities, including ingestion of hot and cold tap water beverages, showering, clothes washing, hand washing, bathing, dish washing, and indirect shower exposure. We conducted our study at a single residence in each of two water utility service areas, one with relatively high and the other low total THM in the residence tap water. To maintain a consistent exposure environment for seven participants, we controlled water use activities, exposure time, air exchange, water flow and temperature, and nonstudy THM sources to the indoor air. We collected reference samples for water supply and air (pre–water use activity), as well as tap water and ambient air samples. We collected blood samples before and after each activity and exhaled breath samples at baseline and postactivity. All hot water use activities yielded a 2-fold increase in blood or breath THM concentrations for at least one individual. The greatest observed increase in blood and exhaled breath THM concentration in any participant was due to showering (direct and indirect), bathing, and hand dishwashing. Average increase in blood THM concentration ranged from 57 to 358 pg/mL due to these activities. More research is needed to determine whether acute and frequent exposures to THM at these concentrations have public health implications. Further research is also needed in designing epidemiologic studies that minimize data collection burden yet maximize accuracy in classification of dermal and inhalation THM exposure during hot water use activities. PMID:16002374

Acute, subchronic, and developmental toxicological properties of lubricating oil base stocks.

PubMed

Dalbey, Walden E; McKee, Richard H; Goyak, Katy Olsavsky; Biles, Robert W; Murray, Jay; White, Russell

2014-01-01

Lubricating oil base stocks (LOBs) are substances used in the manufacture of finished lubricants and greases. They are produced from residue remaining after atmospheric distillation of crude oil that is subsequently fractionated by vacuum distillation and additional refining steps. Initial LOB streams that have been produced by vacuum distillation but not further refined may contain polycyclic aromatic compounds (PACs) and may present carcinogenic hazards. In modern refineries, LOBs are further refined by multistep processes including solvent extraction and/or hydrogen treatment to reduce the levels of PACs and other undesirable constituents. Thus, mildly (insufficiently) refined LOBs are potentially more hazardous than more severely (sufficiently) refined LOBs. This article discusses the evaluation of LOBs using statistical models based on content of PACs; these models indicate that insufficiently refined LOBs (potentially carcinogenic LOBs) can also produce systemic and developmental effects with repeated dermal exposure. Experimental data were also obtained in ten 13-week dermal studies in rats, eight 4-week dermal studies in rabbits, and seven dermal developmental toxicity studies with sufficiently refined LOBs (noncarcinogenic and commonly marketed) in which no observed adverse effect levels for systemic toxicity and developmental toxicity were 1000 to 2000 mg/kg/d with dermal exposures, typically the highest dose tested. Results in both oral and inhalation developmental toxicity studies were similar. This absence of toxicologically relevant findings was consistent with lower PAC content of sufficiently refined LOBs. Based on data on reproductive organs with repeated dosing and parameters in developmental toxicity studies, sufficiently refined LOBs are likely to have little, if any, effect on reproductive parameters.

Springer - Encylcopedia of Immigrant Health (EIH)

EPA Science Inventory

The following description is based on the section of the EIH that is devoted to pesticides: Exposure to chemical pesticides occurs via 3 major pathways of exposure, i.e., inhalation, ingestion (dietary and non dietary) and dermal. Health response varies among individuals and is l...

ESTIMATION OF CHILDREN'S EXPOSURES VIA POORLY CHARACTERIZED PATHWAYS USING CTEPP DATA

EPA Science Inventory

This work involved providing better exposure estimates for poorly characterized pathways (dermal and indirect ingestion) for young children in the CTEPP study. The chemicals used in this analysis were chlorpyrifos and its degradation product 3,5,6-trichloro-2-pyridinol.

Pesticide handling and exposures among cotton farmers in the gambia.

PubMed

Kuye, Rex A; Donham, Kelley J; Marquez, Shannon P; Sanderson, Wayne T; Fuortes, Laurence J; Rautiainen, Risto H; Jones, Martin L; Culp, Kennith R

2007-01-01

There are substantial health hazards to farmers and the environment associated with pesticide use in developing countries. Based on observations by the authors and previous reports, most previous studies in Africa are descriptive in nature. The aim of this study was to investigate how cotton farmers are exposed to pesticides in The Gambia and quantify their pesticide exposures and provide information for the formulation of a policy on pesticide safety for the country. A representative sample of 20 cotton farmers in the Central and Upper River Divisions (CRD and URD) of The Gambia were surveyed by questionnaires. Dermal pesticide exposures among a subset of 10 farmer/pesticide applicators were assessed by dermal patch samples, observation, and postapplication questionnaires. The study revealed that a toxic organochlorine insecticide, Callisulfan (endosulfan), is frequently sprayed on cotton plants by the farmers. The farmers wore no protective equipment and were inadequately dressed for work with this pesticide. Laboratory analysis of the mixed formulation showed a wide range in the concentration of the pesticide solution among the farmer/pesticide applicators and dermal patch samples showed very high residues of endosulfan analytes on their body surfaces. A low level of awareness of pesticide toxicity prevails amonsg cotton farmers in The Gambia. There is a less than adequate control of pesticides and other hazardous agrichemicals in the country.

An FTIR investigation of isocyanate skin absorption using in vitro guinea pig skin.

PubMed

Bello, Dhimiter; Smith, Thomas J; Woskie, Susan R; Streicher, Robert P; Boeniger, Mark F; Redlich, Carrie A; Liu, Youcheng

2006-05-01

Isocyanates may cause contact dermatitis, sensitization and asthma. Dermal exposure to aliphatic and aromatic isocyanates can occur in various exposure settings. The fate of isocyanates on skin is an important unanswered question. Do they react and bind to the outer layer of skin or do they penetrate through the epidermis as unreacted compounds? Knowing the kinetics of these processes is important in developing dermal exposure sampling or decontamination strategies, as well as understanding potential health implications such exposure may have. In this paper the residence time of model isocyanates on hairless guinea pig skin was investigated in vitro using attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectrometry. Model isocyanates tested were octyl isocyanate, polymeric hexamethylene diisocyanate isocyanurate (pHDI), polymeric isophorone diisocyanate isocyanurate (pIPDI) and methylenediphenyl diisocyanate (MDI). Isocyanates in ethyl acetate (30 microL) were spiked directly on the skin to give 0.2-1.8 micromol NCO cm(-2) (NCO = -N=C=O), and absorbance of the isocyanate group and other chemical groups of the molecule were monitored over time. The ATR-FTIR findings showed that polymeric isocyanates pHDI and pIPDI may remain on the skin as unreacted species for many hours, with only 15-20% of the total isocyanate group disappearing in one hour, while smaller compounds octyl isocyanate and MDI rapidly disappear from the skin surface (80+% in 30 min). Isocyanates most likely leave the skin surface by diffusion predominantly, with minimal reaction with surface proteins. The significance of these findings and their implications for dermal exposure sampling and isocyanate skin decontamination are discussed.

Factors affecting variability in the urinary biomarker 1,6-hexamethylene diamine in workers exposed to 1,6-hexamethylene diisocyanate.

PubMed

Gaines, Linda G T; Fent, Kenneth W; Flack, Sheila L; Thomasen, Jennifer M; Whittaker, Stephen G; Nylander-French, Leena A

2011-01-01

Although urinary 1,6-hexamethylene diamine (HDA) is a useful biomarker of exposure to 1,6-hexamethylene diisocyanate (HDI), a large degree of unexplained intra- and inter-individual variability exists between estimated HDI exposure and urine HDA levels. We investigated the effect of individual and workplace factors on urine HDA levels using quantitative dermal and inhalation exposure data derived from a survey of automotive spray painters exposed to HDI. Painters' dermal and breathing-zone HDI-exposures were monitored over an entire workday for up to three separate workdays, spaced approximately one month apart. One urine sample was collected before the start of work with HDI-containing paints, and multiple samples were collected throughout the workday. Using mixed effects multiple linear regression modeling, coverall use resulted in significantly lower HDA levels (p = 0.12), and weekday contributed to significant variability in HDA levels (p = 0.056). We also investigated differences in urine HDA levels stratified by dichotomous and classification covariates using analysis of variance. Use of coveralls (p = 0.05), respirator type worn (p = 0.06), smoker status (p = 0.12), paint-booth type (p = 0.02), and more than one painter at the shop (p = 0.10) were all found to significantly affect urine HDA levels adjusted for creatinine concentration. Coverall use remained significant (p = 0.10), even after adjusting for respirator type. These results indicate that the variation in urine HDA level is mainly due to workplace factors and that appropriate dermal and inhalation protection is required to prevent HDI exposure.

Developing COSHH Essentials: dermal exposure, personal protective equipment and first aid.

PubMed

Garrod, A N I; Rajan-Sithamparanadarajah, R

2003-10-01

The 'control banding' approach in COSHH Essentials combines the potential for harm with the potential for exposure by inhalation to band measures to control exposure at source, as generic strategies. These are simply adapted to specific tasks and circumstances to produce specific control advice. Where it is not possible or practical to use this control advice, the control bands can suggest adequate respiratory protective equipment using 'protection factors'. Proposals in the paper enable the user to identify the right level of respiratory protective equipment (RPE), and to begin selecting suitable RPE. Selection is made through a formatted questionnaire, enabling the user to give the right facts to the supplier. COSHH Essentials applies mainly to exposure by inhalation. However, skin exposure is very common and uptake via the skin can be an important contributor to body dose. This paper examines the factors concerning skin exposure, and the options for banding the potential for harm to the skin or via the skin. Proposals have then been made for dermal exposure control. Planning for emergencies is an important facet of risk control. Proposals are outlined to band chemical hazards for emergency planning according to a minimum of information, i.e. the danger symbol on a product label.

BEHAVIORAL DEVELOPMENT FOLLOWING DAILY EPISODES OF MOTHER-INFANT SEPARATION IN THE RAT

EPA Science Inventory

Use of dermal or inhalation routes of maternal exposure during the postnatal period in rodent developmental neurotoxicity evaluations would be most practical if dams could be separated from their pups during the exposure period. owever, this procedure raises questions concerning ...

40 CFR 161.340 - Toxicology data requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... an organophosphate, or a metabolite or degradation product thereof which causes acetyl cholinesterase... involves purposeful dermal application to, or prolonged exposure of, human skin. (6) Required if use may... supoort products intended for non-food uses if significant exposure of human females of child bearing age...

USE OF MACROACTIVITY APPROACH TO ASSESS DERMAL EXPOSURE

EPA Science Inventory

Currently, data on children's exposures and activities are very limited and insufficient to support quantitative assessments that do not rely heavily on major default assumptions as substitutes for missing information (Cohen Hubal et al. 2000a, b). Cohen Hubal et al. (2000a, b...

REFINED PBPK MODEL OF AGGREGATE EXPOSURE TO METHYL TERTIARY-BUTYL ETHER

EPA Science Inventory

Aggregate (multiple pathway) exposures to methyl tertiary-butyl ether (MTBE) in air and water occur via dermal, inhalation, and oral routes. Previously, physiologically-based pharmacokinetic (PBPK) models have been used to quantify the kinetic behavior of MTBE and its primary met...

Evaluation of silica nanoparticle toxicity after topical exposure for 90 days

PubMed Central

Ryu, Hwa Jung; Seong, Nak-won; So, Byoung Joon; Seo, Heung-sik; Kim, Jun-ho; Hong, Jeong-Sup; Park, Myeong-kyu; Kim, Min-Seok; Kim, Yu-Ri; Cho, Kyu-Bong; Seo, Mu Yeb; Kim, Meyoung-Kon; Maeng, Eun Ho; Son, Sang Wook

2014-01-01

Silica is a very common material that can be found in both crystalline and amorphous forms. Well-known toxicities of the lung can occur after exposure to the crystalline form of silica. However, the toxicities of the amorphous form of silica have not been thoroughly studied. The majority of in vivo studies of amorphous silica nanoparticles (NPs) were performed using an inhalation exposure method. Since silica NPs can be commonly administered through the skin, a study of dermal silica toxicity was necessary to determine any harmful effects from dermal exposures. The present study focused on the results of systemic toxicity after applying 20 nm colloidal silica NPs on rat skin for 90 days, in accordance with the Organization for Economic Cooperation and Development test guideline 411 with a good laboratory practice system. Unlike the inhalation route or gastrointestinal route, the contact of silica NPs through skin did not result in any toxicity or any change in internal organs up to a dose of 2,000 mg/kg in rats. PMID:25565831

Chemical stabilization of polymers: Implications for dermal exposure to additives.

PubMed

Bartsch, N; Girard, M; Schneider, L; Weijgert, V Van De; Wilde, A; Kappenstein, O; Vieth, B; Hutzler, C; Luch, A

2018-04-16

Technical benefits of additives in polymers stand in marked contrast to their associated health risks. Here, a multi-analyte method based on gas chromatography coupled to tandem mass spectrometry (GC-MS/MS) was developed to quantify polymer additives in complex matrices such as low-density polyethylene (LDPE) and isolated human skin layers after dermal exposure ex vivo. That way both technical aspects and dermal exposure were investigated. The effects of polymer additivation on the material were studied using the example of LDPE. To this end, a tailor-made polymer was applied in aging studies that had been furnished with two different mixtures of phenol- and diarylamine-based antioxidants, plasticizers and processing aids. Upon accelerated thermo-oxidative aging of the material, the formation of LDPE degradation products was monitored with attenuated total reflectance-Fourier transformed infrared (ATR-FTIR) spectroscopy. Compared to pure LDPE, a protective effect of added antioxidants could be observed on the integrity of the polymer. Further, thermo-oxidative degradation of the additives and its kinetics were investigated using LDPE or squalane as matrix. The half-lives of additives in both matrices revealed significant differences between the tested additives as well as between LDPE and squalane. For instance, 2-tert-butyl-6-[(3-tert-butyl-2-hydroxy-5-methylphenyl)methyl]-4-methylphenol (Antioxidant 2246) showed a half-life 12 times lower when incorporated in LDPE as compared to squalane. As a model for dermal exposure of consumers, human skin was brought into contact with the tailor-made LDPE containing additives ex vivo in static Franz diffusion cells. The skin was then analyzed for additives and decomposition products. This study proved 10 polymer additives of diverse pysicochemical properties and functionalities to migrate out of the polymer and eventually overcome the intact human skin barrier during contact. Moreover, their individual distribution within distinct skin layers was demonstrated. This is exemplified by the penetration of the procarcinogenic antioxidant N-phenylnaphthalen-2-amine (Neozon D) into the viable epidermis and the permeation through the skin of the neurotoxic plasticizer N-butylbenzenesulfonamide (NBBS). In addition, the analyses of additive degradation products in the isolated skin layers revealed the presence of 2-tert-butyl-4-methylphenol in all layers after contact to a polymer with substances of origin like Antioxidant 2246. Thus, attention needs to be paid to absorption of polymer additives together with their degradation products when it comes to dermal exposure assessment.

Mitochondrial tolerance to single and repeat exposure to simulated sunlight in human epidermal and dermal skin cells.

PubMed

Kelly, J; Murphy, J E J

2016-12-01

Sunlight represents the primary threat to mitochondrial integrity in skin given the unique nature of the mitochondrial genome and its proximity to the electron transport chain. The accumulation of mitochondrial DNA (mtDNA) mutations is a key factor in many human pathologies and this is linked to key roles of mitochondrial function in terms of energy production and cell regulation. The main objective of this study was to evaluate solar radiation induced changes in mitochondrial integrity, function and dynamics in human skin cells using a Q-Sun solar simulator to deliver a close match to the intensity of summer sunlight. Spontaneously immortalised human skin epidermal keratinocytes (HaCaT) and Human Dermal Fibroblasts (HDFn) were divided into two groups. Group A were irradiated once and Group B twice 7days apart and evaluated using cell survival, viability and mitochondrial membrane potential (MMP) and mass at 1, 4 and 7days post one exposure for Group A and 1, 4, 7 and 14days post second exposure for Group B. Viability and survival of HaCaT and HDFn cells decreased after repeat exposure to Simulated Sunlight Irradiation (SSI) with no recovery. HDFn cells showed no loss in MMP after one or two exposures to SSI compared to HaCaT cells which showed a periodic loss of MMP after one exposure with a repeat exposure causing a dramatic decrease from which cells did not recover. Mitochondrial Mass in exposed HDFn cells was consistent with control after one or two exposures to SSI; however mitochondrial mass was significantly decreased in HaCaT cells. Data presented here suggests that mitochondria in epidermal cells are more sensitive to sunlight damage compared to mitochondria in dermal cells, despite their origin, confirming a skin layer specific sensitivity to sunlight, but not as expected. Copyright © 2016 Elsevier B.V. All rights reserved.

Assessment of human exposure to polychlorinated dibenzofurans and dioxins.

PubMed Central

Rappe, C; Nygren, M; Marklund, S; Keller, L O; Bergqvist, P A; Hansson, M

1985-01-01

Fires, explosions and other accidents in polychlorinated biphenyl (PCB)-filled equipment can result in possible exposure of firemen, cleaning personnel and regular workers. Inhalation, dermal exposure and ingestion are the possible routes of exposure. An indirect assessment of the exposure can be made by analyses of wipes, air and water samples and clothes. A direct assessment of exposure can be made by analyses of blood samples, adipose and other tissue samples, feces and bile. PMID:4029099

Isocyanate Exposure Assessment Combining Industrial Hygiene Methods with Biomonitoring for End Users of Orthopedic Casting Products

PubMed Central

Pearson, Ronald L.; Logan, Perry W.; Kore, Anita M.; Strom, Constance M.; Brosseau, Lisa M.; Kingston, Richard L.

2013-01-01

Previous studies have suggested a potential risk to healthcare workers applying isocyanate-containing casts, but the authors reached their conclusions based on immunological or clinical pulmonology test results alone. We designed a study to assess potential exposure to methylene diphenyl diisocyanate (MDI) among medical personnel applying orthopedic casts using two different application methods. Air, dermal, surface, and glove permeation sampling methods were combined with urinary biomonitoring to assess the overall risk of occupational asthma to workers handling these materials. No MDI was detected in any of the personal and area air samples obtained. No glove permeation of MDI was detected. A small proportion of surface (3/45) and dermal wipe (1/60) samples were positive for MDI, but were all from inexperienced technicians. Urinary metabolites of MDI [methylenedianiline (MDA)] were detected in three of six study participants prior to both a ‘dry’ and ‘wet’ application method, five of six after the dry method, and three of six after the wet method. All MDA results were below levels noted in worker or general populations. Our conclusion is that the risk of MDI exposure is small, but unquantifiable. Because there is some potential risk of dermal exposure, medical personnel are instructed to wear a minimum of 5-mil-thick (5 mil = 0.005 inches) nitrile gloves and avoid contact to unprotected skin. This could include gauntlets, long sleeves, and/or a laboratory coat. PMID:23680587

A DNA vaccine delivered by dermal electroporation fully protects cynomolgus macaques against Lassa fever.

PubMed

Cashman, Kathleen A; Wilkinson, Eric R; Shaia, Carl I; Facemire, Paul R; Bell, Todd M; Bearss, Jeremy J; Shamblin, Joshua D; Wollen, Suzanne E; Broderick, Kate E; Sardesai, Niranjan Y; Schmaljohn, Connie S

2017-12-02

Lassa virus (LASV) is an ambisense RNA virus in the Arenaviridae family and is the etiological agent of Lassa fever, a severe hemorrhagic disease endemic to West and Central Africa. 1,2 There are no US Food and Drug Administration (FDA)-licensed vaccines available to prevent Lassa fever. 1,2 in our previous studies, we developed a gene-optimized DNA vaccine that encodes the glycoprotein precursor gene of LASV (Josiah strain) and demonstrated that 3 vaccinations accompanied by dermal electroporation protected guinea pigs from LASV-associated illness and death. Here, we describe an initial efficacy experiment in cynomolgus macaque nonhuman primates (NHPs) in which we followed an identical 3-dose vaccine schedule that was successful in guinea pigs, and a follow-on experiment in which we used an accelerated vaccination strategy consisting of 2 administrations, spaced 4 weeks apart. In both studies, all of the LASV DNA-vaccinated NHPs survived challenge and none of them had measureable, sustained viremia or displayed weight loss or other disease signs post-exposure. Three of 10 mock-vaccinates survived exposure to LASV, but all of them became acutely ill post-exposure and remained chronically ill to the study end point (45 d post-exposure). Two of the 3 survivors experienced sensorineural hearing loss (described elsewhere). These results clearly demonstrate that the LASV DNA vaccine combined with dermal electroporation is a highly effective candidate for eventual use in humans.

Lack of evidence for contact sensitization by Pfiesteria extract.

PubMed

Patterson, Rachel M; Noga, Edward; Germolec, Dori

2007-07-01

Members of the estuarine dinoflagellate genus Pfiesteria are reported to have been responsible for massive fish kills in the southeastern United States. Some reports suggest that exposure to waters having Pfiesteria blooms or occupation-related exposure might result in Pfiesteria-induced dermal irritation and inflammation. Although the toxin has not been isolated and purified, the original data suggested both hydrophilic and hydrophobic toxic components. Some investigators propose that dermonecrotic properties are associated with a hydrophobic fraction. A bioactive C18-bound putative toxin (CPE) extracted from Pfiesteria-laden aquarium water during active fish-killing conditions was examined in the present study to evaluate its potential to produce inflammation and dermal sensitization and to determine whether the inflammation and dermatitis reported in early human exposure studies were allergic or irritant in nature. This fraction was cytotoxic to mouse Neuro-2A cells and primary human epidermal keratinocytes (NHEK) at a concentration of 1 mg/mL. Balb/C mice exposed to 50-200% CPE by skin painting exhibited a 6-10% increase in ear swelling relative to vehicle-treated mice in a primary irritancy assay. There was no increase in lymph node cell proliferation as measured using the local lymph node assay. Exposure to CPE in culture up-regulated interleukin-8 in NHEK, whereas granulocyte macrophage-colony-stimulating factor and tumor necrosis factor alpha were only minimally altered. This study suggests that CPE is cytotoxic to keratinocytes in culture at high concentrations and that it induces mild, localized irritation but not dermal sensitization.

Toxicity review of ethylene glycol monomethyl ether and its acetate ester.

PubMed

Johanson, G

2000-05-01

Ethylene glycol monomethyl ether (EGME) and its acetate ester (EGMEA) are highly flammable, colorless, moderately volatile liquids with very good solubility properties. They are used in paints, lacquers, stains, inks and surface coatings, silk-screen printing, photographic and photo lithographic processes, for example, in the semiconductor industry, textile and leather finishing, production of food-contact plastics, and as an antiicing additive in hydraulic fluids and jet fuel. EGME and EGMEA are efficiently absorbed by inhalation as well as via dermal penetration. Dermal absorption may contribute substantially to the total uptake following skin contact with liquids or vapours containing EGME or EGMEA. EGMEA is rapidly converted to EGME in the body and the two substances are equally toxic in animals. Therefore, the two substances should be considered as equally hazardous to man. Effects on peripheral blood, testes, and sperm have been reported at occupational exposure levels ranging between 0.4 and 10 ppm EGME in air, and with additional, possibly substantial, dermal exposure. Severe malformations and disturbed hematopoiesis have been linked with exposure to EGME and EGMEA at unknown, probably high, levels. Embryonic deaths in monkeys and impaired spermatogenesis in rabbits have been reported after daily oral doses of 12 and 25 mg per kg body weight, respectively. In several studies, increased frequency of spontaneous abortions, disturbed menstrual cycle, and subfertility have been demonstrated in women working in the semiconductor industry. The contribution of EGME in relation to other exposure factors in the semiconductor industry is unclear.

The levels of kerosene components in biological samples after repeated dermal exposure to kerosene in rats.

PubMed

Fujihara, Junko; Hieda, Yoko; Tsujino, Yoshio; Xue, Yuying; Takayama, Koji; Kimura, Kojiro; Dekio, Satoshi

2004-04-01

The current study was experimentally investigated using rats whether or not kerosene components are accumulated from daily repeated dermal exposure. Rats received daily 1h-exposure to kerosene for 5 days (5K), daily 1h-exposure for 4 days and left for 1 day (4KL), a single 1h-exposure (1K), a single 1h-exposure and left for 1 day (1KL), or a single 1h-exposure, sacrificed and left dead for 1 day (1KLD). Kerosene components, trimethylbenzenes (TMBs) and aliphatic hydrocarbons (AHCs) in blood and tissues were determined by GC-MS. In blood, almost the same concentrations of TMBs were detected in the rats sacrificed immediately after exposure (5K, 1K and 1KLD), and only trace levels were detected in the rats sacrificed 1 day after exposure (4 and 1KL). Almost the same levels of AHCs in blood were detected among groups except for the rats sacrificed 1 day after a single exposure (1KL), in which AHCs were slightly lower. These results suggest that (1) AHCs tend to be accumulated from daily exposure, while TMBs do not, (2) the proportions of detected kerosene components in blood can be an indicator of whether the last exposure occurred just before death or not, (3) the kerosene levels last at least 1 day without blood circulation.

Dataset from Dick et al published in Sawyer et al 2016

EPA Pesticide Factsheets

Dataset is a time course description of lindane disappearance in blood plasma after dermal exposure in human volunteersThis dataset is associated with the following publication:Sawyer, M.E., M.V. Evans , C. Wilson, L.J. Beesley, L. Leon, C. Eklund , E. Croom, and R. Pegram. Development of a Human Physiologically Based Pharmacokinetics (PBPK) Model For Dermal Permeability for Lindane. TOXICOLOGY LETTERS. Elsevier Science Ltd, New York, NY, USA, 14(245): pp106-109, (2016).

Decamethylcyclopentasiloxane (D5).

PubMed

2017-01-01

Decamethylcyclopentasiloxane (D5; CAS No. 541-02-6) is a precursor in the production of siloxane polymers for industry and medicine and is a carrier ingredient in many toiletries and cosmetics. D5 has a relatively low order of toxicity following acute administration via the oral, dermal, and inhalation routes of exposure. It is not considered to be a dermal or eye irritant or a dermal sensitizer. There is no appreciable dermal absorption of D5 based on results from in vivo and in vitro studies. It has not been shown to be genotoxic/mutagenic when tested in a number of short-term in vitro and in vivo assays and did not cause reproductive or developmental toxicity in rats. Inhalation exposure of rats to 160 ppm D5 for up to 24 months produced adverse effects in the liver (weight changes and hepatocellular hypertrophy) and uterus (increased incidence of endometrial adenocarcinoma, endometrial adenoma, and adenomatous polyps in several animals); however, the results of recent mode-of-action studies are consistent with a uterine tumorigenesis mechanism that is not relevant for humans. Based on the results of the chronic inhalation study, 160 ppm was determined to be the no-observed-adverse-effect level (NOAEL) and was selected as the point of departure for the derivation of the workplace environmental exposure level (WEEL®) value. This NOAEL was adjusted to account for interindividual variability and residual uncertainty regarding upper respiratory tract changes still occurring at 160 ppm. The resulting 8-h time-weighted average WEEL value of 10 ppm is expected to provide a significant margin of safety against any potential adverse health effects in workers exposed to airborne D5.

Human exposure to trace elements through the skin by direct contact with clothing: Risk assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rovira, Joaquim; Environmental Engineering Laboratory, Departament d'Enginyeria Quimica, Universitat Rovira i Virgili, Av. Països Catalans 26, 43007 Tarragona, Catalonia; Nadal, Martí

Metals in textile products and clothing are used for many purposes, such as metal complex dyes, pigments, mordant, catalyst in synthetic fabrics manufacture, synergists of flame retardants, antimicrobials, or as water repellents and odour-preventive agents. When present in textile materials, heavy metals may mean a potential danger to human health. In the present study, the concentrations of a number of elements (Al, As, B, Ba, Be, Bi, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mn, Mo, Ni, Pb, Sb, Sc, Se, Sm, Sn, Sr, Tl, V, and Zn) were determined in skin-contact clothes. Analysed clothes were made of different materials,more » colours, and brands. Interestingly, we found high levels of Cr in polyamide dark clothes (605 mg/kg), high Sb concentrations in polyester clothes (141 mg/kg), and great Cu levels in some green cotton fabrics (around 280 mg/kg). Dermal contact exposure and human health risks for adult males, adult females, and for <1-year-old children were assessed. Non-carcinogenic and carcinogenic risks were below safe (HQ<1) and acceptable (<10{sup −6}) limits, respectively, according to international standards. However, for Sb, non-carcinogenic risk was above 10% of the safety limit (HQ>0.1) for dermal contact with clothes. - Highlights: • We determined in skin-contact clothes the concentrations of a number of metals. • Dermal contact exposure and health risks for adults and for 1-year-old children were assessed. • Carcinogenic risks were considered as acceptable (<10{sup −6}). • For non-carcinogenic risks, only Sb exceeded a 10% of the HQ for dermal contact with clothes.« less

Mitochondrial gene expression changes in cultured human skin cells following simulated sunlight irradiation.

PubMed

Kelly, J; Murphy, J E

2018-02-01

Exposure of skin to simulated sunlight irradiation (SSI) has being extensively researched and shown to be the main cause for changes in the skin including changes in cellular function and generation of reactive oxygen species (ROS). This oxidative stress can subsequently exert downstream effects and the subcellular compartments most affected by this oxidative stress are mitochondria. The importance of functional mitochondrial morphology is apparent as morphological defects are related to many human diseases including diabetes mellitus, liver disease, neurodegenerative diseases, aging and cancer. The main objective of this study was to evaluate solar radiation-induced changes in mitochondrial gene expression in human skin cells using a Q-Sun solar simulator to deliver a close match to the intensity of summer sunlight. Spontaneously immortalised human skin epidermal keratinocytes (HaCaT) and Human Dermal Fibroblasts (HDFn) were divided into two groups. Group A were irradiated once and Group B twice 7days apart; following irradiation, mitochondrial gene expression was evaluated 1, 4 and 7days post primary exposure for group A and 1, 4, 7 and 14days post-secondary exposure for group B. Both the epidermal and dermal cells displayed significant reduced expression of the genes analysed for mitochondrial morphology and function; however, epidermal cells displayed this reduction post SSI earlier then dermal cells at multiple time points. The data presented here reinforces the fact that epidermal cells, while displaying a heightened sensitivity to sunlight, are less prone to changes in gene expression, while dermal cells, which appear to be more resilient are possibly more prone to genomic instability and mitochondrial damage. Copyright © 2017 Elsevier B.V. All rights reserved.

Efficacy of topical phenol decontamination strategies on severity of acute phenol chemical burns and dermal absorption: in vitro and in vivo studies in pig skin.

PubMed

Monteiro-Riviere, N A; Inman, A O; Jackson, H; Dunn, B; Dimond, S

2001-05-01

Pure phenol is colorless and used in the manufacture of phenolic resins, plastics, explosives, fertilizers, paints, rubber, textiles, adhesives, pharmaceuticals, paper, soap, and wood preservatives. The purpose of this study was to compare the efficacy of several phenol decontamination strategies following dermal exposure using the pig as a model for human exposure, and then assess the effect of the two best treatments on phenol absorption in the isolated perfused porcine skin flap (IPPSF). Six anesthetized Yorkshire pigs were exposed to 89% aqueous phenol for 1 min using Hilltop chambers (10 skin sites/pig; 400 microl/site). Exposure to phenol was followed by one of 10 different decontamination procedures: 1-, 5-, 15-, and 30-min water wash; Ivory soap solution; polyethylene glycol (PEG 400); PEG 400/industrial methylated spirits (IMS); PEG 400/ethanol (EtOH); polyvinyl pyrrolidone (PVP)/70% isopropanol (IPA); and 70% IPA. For each of the last five strategies, 1-min treatment washes were repeatedly alternated with 1-min water washes for a total of 15 min. Evaluation was based on scoring of erythema, edema, and histological parameters such as intracellular and intercellular epidermal edema, papillary dermal edema, perivascular infiltrates, pyknotic stratum basale cells, and epidermal-dermal separation. It was concluded that PEG 400 and 70% IPA were superior to the other treatments investigated and equally efficacious in the reduction of phenol-induced skin damage. In addition, phenol absorption was assessed utilizing the two most effective in vivo treatments in the IPPSF. The assessment of percutaneous absorption of phenol found the PEG 400, 70% IPA, and 15-min water treatments significantly (P < 0.05) reduced phenol absorption relative to no treatment.

Survey of dermal protection in Washington State collision repair industry.

PubMed

Ceballos, Diana M; Fent, Kenneth W; Whittaker, Stephen G; Gaines, Linda G T; Thomasen, Jennifer M; Flack, Sheila L; Nylander-French, Leena A; Yost, Michael G; Reeb-Whitaker, Carolyn K

2011-09-01

Substantial exposure to isocyanates may occur during spray painting in autobody shops, yet information is lacking on the efficacy of the protective clothing used during spray painting. We investigated the personal and workplace factors associated with painters' dermal protection use during a large-scale exposure assessment study. Survey data indicated that 69% of painters always used gloves, with latex gloves (47%) and nitrile gloves (34%) used most frequently. Among latex glove users, 53% used thin latex (0.05-0.13 mm), 6% used medium latex (0.15-0.20 mm), and 12% used thick latex (> 0.20 mm). Among nitrile glove users, 27% used thin nitrile and 45% used medium nitrile. Sixty-three percent of painters always used coveralls, 44% preferring one particular brand. Although overspray presents an opportunity for dermal exposure to the neck and face, only 19% of painters protected these areas with personal protective equipment. Painters who always used coveralls were more likely to use gloves (odds ratio = 7.9, p = 0.061). Painters who reported ever having smoked cigarettes used gloves (p = 0.05) and coveralls (p = 0.04) more frequently. Painters who sprayed more than 34 clear coat jobs per month used coveralls most frequently (p = 0.038). Exact logistic regressions along with random sample calculations indicated that the survey results were independent of the shops. Because of the small sample size in this study, future research is warranted to corroborate these results. Studying the effectiveness of gloves and coveralls against polyurethane paints and understanding the underlying motivators and preferences for painters and business owners is needed for the development of best practices for the selection and use of dermal protection.

Immunotoxicity and allergic potential induced by topical application of dimethyl carbonate (DMC) in a murine model

PubMed Central

Anderson, Stacey E.; Franko, Jennifer; Anderson, Katie L.; Munson, Albert E.; Lukomska, Ewa; Meade, B. Jean

2015-01-01

Dimethyl carbonate (DMC) is an industrial chemical, used as a paint and adhesive solvent, with the potential for significant increases in production. Using select immune function assays, the purpose of these studies was to evaluate the immunotoxicity of DMC following dermal exposure using a murine model. Following a 28-day exposure, DMC produced a significant decrease in thymus weight at concentrations of 75% and greater. No effects on body weight, hematological parameters (erythrocytes, leukocytes, and their differentials), or immune cell phenotyping (B-cells, T-cells, and T-cell sub-sets) were identified. The IgM antibody response to sheep red blood cell (SRBC) was significantly reduced in the spleen but not the serum. DMC was not identified to be an irritant and evaluation of the sensitization potential, conducted using the local lymph node assay (LLNA) at concentrations ranging from 50–100%, did not identify increases in lymphocyte proliferation. These results demonstrate that dermal exposure to DMC induces immune suppression in a murine model and raise concern about potential human exposure and the need for occupational exposure regulations. PMID:22953780

Exploratory breath analyses for assessing toxic dermal exposure of firefighters during suppression of structural burns

EPA Science Inventory

Firefighters wear fireproof clothing and self-contained breathing apparatus (SCBA) during rescue and fire suppression activities to protect against acute effects from heat and toxic chemicals. Fire services are also concerned about long-term health outcomes from chemical exposure...

Development of a Multiroute Human PBPK Model for Bromodichloromethane (BDCM)

EPA Science Inventory

BDCM is an animal carcinogen and developmental toxicant. Due to its presence as a disinfection byproduct in finished drinking water, BDCM may pose a risk for exposure via ingestion, inhalation or dermal exposure. Utilizing a unique data set in which human subjects were exposed ...

EXHALED HUMAN BREATH MEASUREMENT OF JET FUEL CONSTITUENTS: DISTINGUISHING BETWEEN INHALATION AND DERMAL EXPOSURE ROUTES

EPA Science Inventory

In response to anecdotal reports, perceived health issues, and widespread complaints, the U.S. military launched an investigation into the occupational and environmental human exposure to jet fuel. The work described in the presentation assesses the correlation between two breat...

The Utility of Naphthyl-Keratin Adducts as Biomarkers for Jet-Fuel Exposure

EPA Science Inventory

We investigated the association between biomarkers of dermal exposure, naphthyl-keratin adducts (NKA), and urine naphthalene biomarker levels in 105 workers routinely exposed to jet-fuel. A moderate correlation was observed between NKA and urine naphthalene levels (p = 0.061). Th...

Solar-simulated radiation and heat treatment induced metalloproteinase-1 expression in cultured dermal fibroblasts via distinct pathways: implications on reduction of sun-associated aging.

PubMed

Lan, Cheng-Che E; Wu, Ching-Shang; Yu, Hsin-Su

2013-12-01

Sun exposure is an important environmental factor affecting human beings. Most knowledge regarding solar aging focused on light radiation (photoaging), and little emphasis has been placed on heat, a factor that is also closely associated with sun exposure. This study was launched to evaluate the effects of simulated solar radiation (SSR) and environmental heat on skin fibroblasts in terms of dermal aging. Cultured human dermal fibroblasts were treated with moderate amount of SSR (200J/cm(2)) and heat (+2°C). The metalloproteinase-1 (MMP-1) expression was used as a surrogate marker for dermal aging and the involved regulatory mechanisms were explored. Both treatment conditions did not affect viability but significantly increased the expressions of MMP-1. In parallel, both treatments increased the intracellular levels of reactive oxygen species (ROS), but the increase induced by SSR is much greater than heat. In contrast, transient receptor potential vanilloid 1 (TRPV-1), the sensor of environmental heat, was upregulated by heat but not SSR treatment. Pretreating fibroblasts with antioxidant abrogated the SSR-induced MMP-1 but has limited effect on heat-induced MMP-1. On the other hand, TRPV-1 antagonist pretreatment reduced heat-induced MMP-1 in fibroblasts but not their SSR-treated counterparts. Both SSR and heat induced MMP-1 expression in dermal fibroblasts but through different pathways. As current strategies for reducing sun-related aging focused on filtering of light and use of antioxidants, future strategies design to reduce solar aging should also incorporate heat-induced aging into consideration. Copyright © 2013 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

Dermal uptake of Tetrabromobisphenol A TBBPA by female Wistar Han rat and human skin

EPA Science Inventory

TBBPA, a brominated analog of Bisphenol A, is the highest production volume brominated flame retardant in production and human exposure is ubiquitous. Although the major route of exposure to TBBPA is oral uptake, skin penetration is possible. In the studies presented here, the de...

Principles and Procedures for Evaluating the Toxicity of Household Substances. Revised.

ERIC Educational Resources Information Center

National Academy of Sciences - National Research Council, Washington, DC. Assembly of Life Sciences.

This report was prepared for use by the professional toxicologist. It contains chapters on ingestion exposure, dermal and dye toxicity tests, inhalation exposure, chronic toxicity and carcinogenicity tests, mutagenicity tests, reproduction and teratogenicity tests, and behavioral toxicity tests. In addition, regulations under the Federal Hazardous…

Workflow and Proof of Concept for Non-Targeted Analysis of Environmental Samples by LC-MS/MS

EPA Science Inventory

The human exposure includes thousands of chemicals acquired through various routes of exposure such as inhalation, ingestion, dermal contact, and indirect ingestion. Rapid assessment and screening of these chemicals is a difficult challenge facing EPA in its mission to protect pu...

CYTOKINE RESPONSES TO DERMAL ISOCYANATE EXPOSURE IN DRAINING LYMPH NODES ARE NOT PREDICTIVE OF AIRWAY RESPONSES AFTER AIRWAY CHALLENGE

EPA Science Inventory

Exposure to low molecular weight chemicals including isocyanates has been linked to occupational asthma. A strong need exists for the rapid and accurate identification of chemical respiratory sensitizers. Recently, some investigators have proposed that chemicals may be identified...

40 CFR 158.1070 - Post-application exposure data requirements table.

Code of Federal Regulations, 2011 CFR

2011-07-01

... applicable residue dissipation data to dermal exposure data is required. 3. Turf grass transferable residue dissipation data are required when pesticides are applied to turf grass. Dislodgeable foliar residue dissipation data are required when pesticides are applied to the foliage of plants other than turf grass. 4...

40 CFR 158.1070 - Post-application exposure data requirements table.

Code of Federal Regulations, 2010 CFR

2010-07-01

... applicable residue dissipation data to dermal exposure data is required. 3. Turf grass transferable residue dissipation data are required when pesticides are applied to turf grass. Dislodgeable foliar residue dissipation data are required when pesticides are applied to the foliage of plants other than turf grass. 4...

Evaluation of the acute dermal exposure of the ethanolic and hexanic extracts from leaves of Schinus molle var. areira L. in rats.

PubMed

Bras, Cristina; Gumilar, Fernanda; Gandini, Norberto; Minetti, Alejandra; Ferrero, Adriana

2011-10-11

Schinus molle var. areira L. (Anacardiaceae) is employed in herbal medicine for many conditions, including respiratory, urinary and menstrual disorders, and as a digestive stimulant, diuretic, astringent and antidepressant. It is also known for its topical use as wound healer, antiseptic, for skin disorders and as repellent and insecticide. In the present work, the acute dermal exposure to ethanolic and hexanic extracts from leaves of Schinus molle var. areira was studied in rats. A single dose of 2000 mg/kg of body weight of ethanolic and hexanic extracts from leaves was applied on the shaved skin of male and female rats. After 24h of exposure, the patch was removed and any sign of irritation was recorded. Behavioral and functional parameters in a functional observational battery and motor activity in an open field were assessed after the exposure to the extracts. Then, after 14 days of observation, animals were retested. Finally, histopathological studies were conducted on several organs. Slight signs of erythema and edema were observed in the skin site of exposure, but they disappeared after 48 h. The exposure to the hexanic extract produced an increase in parameters of activity, rearing and arousal assessed in the functional observational battery, which reversed after 14 days. On the other hand, the ethanolic extract caused an increase in locomotor activity, reflected in a higher number of rearings performed in the open field in the evaluation carried out on Day 14. No histopathological alterations were detected in the analyzed organs. The results show that the acute dermal exposure of the ethanolic and hexanic extracts from leaves of Schinus molle var. areira only causes a slight and reversible skin irritation, and a mild stimulatory effect in rats. All these indicate that the topical use of these extracts would be safe. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Migration of Ag- and TiO2-(Nano)particles from textiles into artificial sweat under physical stress: experiments and exposure modeling.

PubMed

von Goetz, N; Lorenz, C; Windler, L; Nowack, B; Heuberger, M; Hungerbühler, K

2013-09-03

Engineered nanoparticles (ENP) are increasingly used to functionalize textiles taking advantage, e.g., of the antimicrobial activity of silver (Ag)-ENP or the UV-absorption of titania (TiO2)-ENP. Mobilization and migration of ENPs from the textile into human sweat can result in dermal exposure to these nanoobjects and their aggregates and agglomerates (NOAA). In this study we assessed exposure to NOAA migrating from commercially available textiles to artificial sweat by an experimental setup that simulates wear-and-tear during physical activity. By combining physical stress with incubation in alkaline and acidic artificial sweat solutions we experimentally realized a worst case scenario for wearing functionalized textiles during sports activities. This experimental approach is not limited to NOAA, but can be used for any other textile additive. Out of four investigated textiles, one T-shirt and one pair of trousers with claimed antimicrobial properties were found to release Ag <450 nm in detectable amounts (23-74 μg/g/L). Textiles containing TiO2 for UV protection did not release significant amounts of TiO2 <450 nm, but the antimicrobial T-shirt released both TiO2 and Ag <450 nm. The silver was present in dissolved and particulate form, whereas TiO2 was mainly found as particulate. On the basis of our experimental results we calculated external dermal exposure to Ag and TiO2 for male and female adults per use. For silver, maximal amounts of 17.1 and 8.2 μg/kg body weight were calculated for total and particulate Ag <450 nm, respectively. For TiO2, the exposure levels amount to maximal 11.6 μg/kg body weight for total (mainly particulate) TiO2. In comparison with other human exposure pathways, dermal exposure to NOAA from textiles can be considered comparably minor for TiO2-NOAA, but not for Ag-NOAA.

Immunotoxicity evaluation of jet a jet fuel in female rats after 28-day dermal exposure.

PubMed

Mann, Cynthia M; Peachee, Vanessa L; Trimmer, Gary W; Lee, Ji-Eun; Twerdok, Lorraine E; White, Kimber L

2008-01-01

The potential for jet fuel to modulate immune functions has been reported in mice following dermal, inhalation, and oral routes of exposure; however, a functional evaluation of the immune system in rats following jet fuel exposure has not been conducted. In this study potential effects of commercial jet fuel (Jet A) on the rat immune system were assessed using a battery of functional assays developed to screen potential immunotoxic compounds. Jet A was applied to the unoccluded skin of 6- to 7-wk-old female Crl:CD (SD)IGS BR rats at doses of 165, 330, or 495 mg/kg/d for 28 d. Mineral oil was used as a vehicle to mitigate irritation resulting from repeated exposure to jet fuel. Cyclophosphamide and anti-asialo GM1 were used as positive controls for immunotoxic effects. In contrast to reported immunotoxic effects of jet fuel in mice, dermal exposure of rats to Jet A did not result in alterations in spleen or thymus weights, splenic lymphocyte subpopulations, immunoglobulin (Ig) M antibody-forming cell response to the T-dependent antigen, sheep red blood cells (sRBC), spleen cell proliferative response to anti-CD3 antibody, or natural killer (NK) cell activity. In each of the immunotoxicological assays conducted, the positive control produced the expected results, demonstrating the assay was capable of detecting an effect if one had occurred. Based on the immunological parameters evaluated under the experimental conditions of the study, Jet A did not adversely affect immune responses of female rats. It remains to be determined whether the observed difference between this study and some other studies reflects a difference in the immunological response of rats and mice or is the result of other factors.

Investigations into the Immunotoxicity and Allergic Potential Induced by Topical Application of N-Butylbenzenesulfonamide (NBBS) in a Murine Model

PubMed Central

Marrocco, Antonella; Meade, B. Jean; Long, Carrie M.; Lukomska, Ewa; Marshall, Nikki B.; Anderson, Stacey E.

2015-01-01

N-Butylbenzene sulfonamide (NBBS) is a commonly used plasticizer found in numerous products. Due to its extensive use, lack of adequate toxicological data, and suspicion of toxicity based on the presence of structural alerts, it was nominated to the National Toxicology Program for comprehensive toxicological testing. The purpose of this study was to evaluate the potential for hypersensitivity and immune suppression following dermal exposure to NBBS using a murine model. NBBS tested negative in a combined irritancy/local lymph node assay (LLNA), classifying it as nonirritating and nonsensitizing. To estimate the immunosuppressive potential of NBBS, assays that assessed immunotoxicity were performed, including the immumnoglobulin (Ig) M response to T-cell-dependent antigen sheep red blood cells (SRBC), using the plaque-forming cell (PFC) assay and immune cell phenotyping. After a 28-d treatment with NBBS, mice exposed to the lowest concentration (25% NBBS) showed a significant increase in IgM-producing B cells in the spleen. No marked changes were identified in immune cell markers in the lymph node. In contrast to body weight, a significant elevation in kidney and liver weight was observed following dermal exposure to all concentrations of NBBS. These results demonstrate that dermal exposure to NBBS, other than liver and kidney toxicity, did not apparently induce immunotoxicity in a murine model. PMID:26291892

A review of critical factors for assessing the dermal absorption of metal oxide nanoparticles from sunscreens applied to humans, and a research strategy to address current deficiencies.

PubMed

Gulson, Brian; McCall, Maxine J; Bowman, Diana M; Pinheiro, Teresa

2015-11-01

Metal oxide nanoparticles in sunscreens provide broad-spectrum ultraviolet protection to skin. All studies to assess dermal penetration of nanoparticles have unanimously concluded that the overwhelming majority of nanoparticles remain on the outer surface of the skin. However, possibly due to many different experimental protocols in use, conclusions over the potential penetration to viable skin are mixed. Here, we review several factors that may influence experimental results for dermal penetration including the species studied (human, or animal model), size and coating of the metal oxide nanoparticles, composition of the sunscreen formulation, site of sunscreen application, dose and number of applications, duration of the study, types of biological samples analysed, methods for analysing samples, exposure to UV and skin flexing. Based on this information, we suggest an appropriate research agenda involving international collaboration that maximises the potential for dermal absorption of nanoparticles, and their detection, under normal conditions of sunscreen use by humans. If results from this research agenda indicate no absorption is observed, then concerns over adverse health effects from the dermal absorption of nanoparticles in sunscreens may be allayed.

Dermal uptake of petroleum substances.

PubMed

Jakasa, Ivone; Kezic, Sanja; Boogaard, Peter J

2015-06-01

Petroleum products are complex substances comprising varying amounts of linear and branched alkanes, alkenes, cycloalkanes, and aromatics which may penetrate the skin at different rates. For proper interpretation of toxic hazard data, understanding their percutaneous absorption is of paramount importance. The extent and significance of dermal absorption of eight petroleum substances, representing different classes of hydrocarbons, was evaluated. Literature data on the steady-state flux and permeability coefficient of these substances were evaluated and compared to those predicted by mathematical models. Reported results spanned over 5-6 orders of magnitude and were largely dependent on experimental conditions in particular on the type of the vehicle used. In general, aromatic hydrocarbons showed higher dermal absorption than more lipophilic aliphatics with similar molecular weight. The results showed high variation and were largely influenced by experimental conditions emphasizing the need of performing the experiments under "in use" scenario. The predictive models overestimated experimental absorption. The overall conclusion is that, based on the observed percutaneous penetration data, dermal exposure to petroleum hydrocarbons, even of aromatics with highest dermal absorption is limited and highly unlikely to be associated with health risks under real use scenarios. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Migration of Beryllium via Multiple Exposure Pathways among Work Processes in Four Different Facilities

PubMed Central

Armstrong, Jenna L.; Day, Gregory A.; Park, Ji Young; Stefaniak, Aleksandr B.; Stanton, Marcia L.; Deubner, David C.; Kent, Michael S.; Schuler, Christine R.; Virji, M. Abbas

2016-01-01

Inhalation of beryllium is associated with the development of sensitization; however, dermal exposure may also be important. The primary aim of this study was to elucidate relationships among exposure pathways in four different manufacturing and finishing facilities. Secondary aims were to identify jobs with increased levels of beryllium in air, on skin, and on surfaces; identify potential discrepancies in exposure pathways, and determine if these are related to jobs with previously identified risk. Beryllium was measured in air, on cotton gloves, and on work surfaces. Summary statistics were calculated and correlations among all three measurement types were examined at the facility and job level. Exposure ranking strategies were used to identify jobs with higher exposures. The highest air, glove, and surface measurements were observed in beryllium metal production and beryllium oxide ceramics manufacturing jobs that involved hot processes and handling powders. Two finishing and distribution facilities that handle solid alloy products had lower exposures than the primary production facilities, and there were differences observed among jobs. For all facilities combined, strong correlations were found between air-surface (rp ≥ 0.77), glove-surface (rp ≥ 0.76), and air-glove measurements (rp ≥ 0.69). In jobs where higher risk of beryllium sensitization or disease has been reported, exposure levels for all three measurement types were higher than in jobs with lower risk, though they were not the highest. Some jobs with low air concentrations had higher levels of beryllium on glove and surface wipe samples, suggesting a need to further evaluate the causes of the discrepant levels. Although such correlations provide insight on where beryllium is located throughout the workplace, they cannot identify the direction of the pathways between air, surface, or skin. Ranking strategies helped to identify jobs with the highest combined air, glove, and/or surface exposures. All previously identified high-risk jobs had high air concentrations, dermal mass loading, or both, and none had low dermal and air. We have found that both pathways are relevant. PMID:25357184

Children’s Phthalate Intakes and Resultant Cumulative Exposures Estimated from Urine Compared with Estimates from Dust Ingestion, Inhalation and Dermal Absorption in Their Homes and Daycare Centers

PubMed Central

Bekö, Gabriel; Weschler, Charles J.; Langer, Sarka; Callesen, Michael; Toftum, Jørn; Clausen, Geo

2013-01-01

Total daily intakes of diethyl phthalate (DEP), di(n-butyl) phthalate (DnBP), di(isobutyl) phthalate (DiBP), butyl benzyl phthalate (BBzP) and di(2-ethylhexyl) phthalate (DEHP) were calculated from phthalate metabolite levels measured in the urine of 431 Danish children between 3 and 6 years of age. For each child the intake attributable to exposures in the indoor environment via dust ingestion, inhalation and dermal absorption were estimated from the phthalate levels in the dust collected from the child’s home and daycare center. Based on the urine samples, DEHP had the highest total daily intake (median: 4.42 µg/d/kg-bw) and BBzP the lowest (median: 0.49 µg/d/kg-bw). For DEP, DnBP and DiBP, exposures to air and dust in the indoor environment accounted for approximately 100%, 15% and 50% of the total intake, respectively, with dermal absorption from the gas-phase being the major exposure pathway. More than 90% of the total intake of BBzP and DEHP came from sources other than indoor air and dust. Daily intake of DnBP and DiBP from all exposure pathways, based on levels of metabolites in urine samples, exceeded the Tolerable Daily Intake (TDI) for 22 and 23 children, respectively. Indoor exposures resulted in an average daily DiBP intake that exceeded the TDI for 14 children. Using the concept of relative cumulative Tolerable Daily Intake (TDIcum), which is applicable for phthalates that have established TDIs based on the same health endpoint, we examined the cumulative total exposure to DnBP, DiBP and DEHP from all pathways; it exceeded the tolerable levels for 30% of the children. From the three indoor pathways alone, several children had a cumulative intake that exceeded TDIcum. Exposures to phthalates present in the air and dust indoors meaningfully contribute to a child’s total intake of certain phthalates. Such exposures, by themselves, may lead to intakes exceeding current limit values. PMID:23626820

Lack of Evidence for Contact Sensitization by Pfiesteria Extract

PubMed Central

Patterson, Rachel M.; Noga, Edward; Germolec, Dori

2007-01-01

Background Members of the estuarine dinoflagellate genus Pfiesteria are reported to have been responsible for massive fish kills in the southeastern United States. Some reports suggest that exposure to waters having Pfiesteria blooms or occupation-related exposure might result in Pfiesteria-induced dermal irritation and inflammation. Although the toxin has not been isolated and purified, the original data suggested both hydrophilic and hydrophobic toxic components. Some investigators propose that dermonecrotic properties are associated with a hydrophobic fraction. Objectives A bioactive C18-bound putative toxin (CPE) extracted from Pfiesteria-laden aquarium water during active fish-killing conditions was examined in the present study to evaluate its potential to produce inflammation and dermal sensitization and to determine whether the inflammation and dermatitis reported in early human exposure studies were allergic or irritant in nature. Results This fraction was cytotoxic to mouse Neuro-2A cells and primary human epidermal keratinocytes (NHEK) at a concentration of 1 mg/mL. Balb/C mice exposed to 50–200% CPE by skin painting exhibited a 6–10% increase in ear swelling relative to vehicle-treated mice in a primary irritancy assay. There was no increase in lymph node cell proliferation as measured using the local lymph node assay. Exposure to CPE in culture up-regulated interleukin-8 in NHEK, whereas granulocyte macrophage–colony-stimulating factor and tumor necrosis factor α were only minimally altered. Conclusions This study suggests that CPE is cytotoxic to keratinocytes in culture at high concentrations and that it induces mild, localized irritation but not dermal sensitization. PMID:17637917

Hydrolysis of a series of parabens by skin microsomes and cytosol from human and minipigs and in whole skin in short-term culture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jewell, Christopher; Prusakiewicz, Jeffery J.; Ackermann, Chrisita

2007-12-01

Parabens are esters of 4-hydroxybenzoic acid and used as anti-microbial agents in a wide variety of toiletries, cosmetics and pharmaceuticals. It is of interest to understand the dermal absorption and hydrolysis of parabens, and to evaluate their disposition after dermal exposure and their potential to illicit localised toxicity. The use of minipig as a surrogate model for human dermal metabolism and toxicity studies, justifies the comparison of paraben metabolism in human and minipig skin. Parabens are hydrolysed by carboxylesterases to 4-hydroxybenzoic acid. The effects of the carboxylesterase inhibitors paraoxon and bis-nitrophenylphosphate provided evidence of the involvement of dermal carboxylesterases inmore » paraben hydrolysis. Loperamide, a specific inhibitor of human carboxylesterase-2 inhibited butyl- and benzylparaben hydrolysis in human skin but not methylparaben or ethylparaben. These results show that butyl- and benzylparaben are more selective substrates for human carboxylesterase-2 in skin than the other parabens examined. Parabens applied to the surface of human or minipig skin were absorbed to a similar amount and metabolised to 4-hydroxybenzoic acid during dermal absorption. These results demonstrate that the minipig is a suitable model for man for assessing dermal absorption and hydrolysis of parabens, although the carboxylesterase profile in skin differs between human and minipig.« less

Role of clothing in both accelerating and impeding dermal absorption of airborne SVOCs.

PubMed

Morrison, Glenn C; Weschler, Charles J; Bekö, Gabriel; Koch, Holger M; Salthammer, Tunga; Schripp, Tobias; Toftum, Jørn; Clausen, Geo

2016-01-01

To assess the influence of clothing on dermal uptake of semi-volatile organic compounds (SVOCs), we measured uptake of selected airborne phthalates for an individual wearing clean clothes or air-exposed clothes and compared these results with dermal uptake for bare-skinned individuals under otherwise identical experimental conditions. Using a breathing hood to isolate dermal from inhalation uptake, we measured urinary metabolites of diethylphthalate (DEP) and di-n-butylphthalate (DnBP) from an individual exposed to known concentrations of these compounds for 6 h in an experimental chamber. The individual wore either clean (fresh) cotton clothes or cotton clothes that had been exposed to the same chamber air concentrations for 9 days. For a 6-h exposure, the net amounts of DEP and DnBP absorbed when wearing fresh clothes were, respectively, 0.017 and 0.007 μg/kg/(μg/m(3)); for exposed clothes the results were 0.178 and 0.261 μg/kg/(μg/m(3)), respectively (values normalized by air concentration and body mass). When compared against the average results for bare-skinned participants, clean clothes were protective, whereas exposed clothes increased dermal uptake for DEP and DnBP by factors of 3.3 and 6.5, respectively. Even for non-occupational environments, wearing clothing that has adsorbed/absorbed indoor air pollutants can increase dermal uptake of SVOCs by substantial amounts relative to bare skin.

Antioxidant Nanoplatforms for Dermal Delivery: Melatonin.

PubMed

Milan, Aroha Sanchez; Campmany, Ana Cristina Calpena; Naveros, Beatriz Clares

2017-01-01

Melatonin is emerging as a promising therapeutic agent, mainly due to its role as antioxidant. Substantial evidences show that melatonin is potentially effective in a variety of diseases as cancer, inflammation and neurodegenerative diseases. The excellent antioxidant capacity with pharmacokinetics characteristics and the emerging search for new pharmaceutical nanotechnology based systems, make it particularly attractive to elaborate nanoplatforms based on melatonin for biomedical or cosmetic dermal applications. Different nanosystems for dermal delivery have been investigated. This review focuses on nanocarrier production strategies, dermal melatonin application and delivery advances in vivo and in vitro. Equally, future perspectives of this assisted melatonin delivery have also been discussed. In the current review, we have revised relevant articles of the available literature using the major scientific databases. One hundred and thirteen papers were included in the review, the majority of which represent latest researches in nanosized platforms for the dermal delivery of melatonin including liposomes, ethosomes, niosomes, polymeric nanoparticles, solid lipid nanoparticles and cyclodextrins. Furthermore, relevant papers reporting in vitro and in vivo application studies of these nano-based melatonin platforms were also discussed. The use of nanoplatforms for the dermal melatonin delivery as antioxidant agent could improve the efficacy of conventional melatonin administration due to the preservation of the drug from premature oxidation and the enhancement of drug permeation through the skin providing greater exposure times. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

76 FR 82146 - Tepraloxydim; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-30

... removes established tolerances for residues of tepraloxydim on ``Lentil, seed'' and ``Pea, dry, seed,'' as... toxicity via the oral, dermal, and inhalation routes of exposure. It produces minimal [[Page 82148

Safety assessment and toxicological profiling of a novel combinational sunprotective dermal formulation containing melatonin and pumpkin seed oil.

PubMed

Bora, Nilutpal Sharma; Pathak, Manash Pratim; Mandal, Santa; Mazumder, Bhaskar; Policegoudra, Rudragoud; Raju, Pakalapati Srinivas; Chattopadhyay, Pronobesh

2017-10-01

Ultraviolet (UV) radiation exposure has been known to cause irreparable damages to human skin. The daunting risk of UV radiation exposure faced by military personnel led to the development of a sunscreen formulation which has superior sun protection factor combined with the ability to counteract reactive oxygen species. The present work deals with the preclinical safety evaluation of the sunscreen formulation comprising of four US FDA approved UV filters; namely avobenzone, octinoxate, oxybenzone, titanium dioxide along with melatonin and pumpkin seed oil, via OECD protocols of assessing acute oral and dermal toxicity; skin sensitizing; skin irritating; ocular irritating and genotoxic potential. Both oral and dermal LD 50 values were found to be ˃2000 mg/kg body weight in adult Wistar albino rats using acute dermal and oral toxicity tests. The sunscreen formulation was found to be non-sensitizing to the skin of guinea pigs and non-irritating to both skin and eyes of rabbits. The sunscreen formulation was also found to be non-mutagenic which was affirmed by a battery of genotoxicity and muagenicity assays. The results obtained from this preclinical study indicated that the sunscreen formulation is non toxic and safe in animal models. This study along with additional preclinical evaluations may serve as a basis for considering the formulation as a potential candidate for further trials to establish its efficacy, tolerability and applicability. Copyright © 2017 Elsevier Inc. All rights reserved.

Urinary Biomarker, Dermal, and Air Measurement Results for 2,4-D and Chlorpyrifos Farm Applicators in the Agricultural Health Study

EPA Science Inventory

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-D and chlorpyrifos to assess exposure levels and potential determinants of exposure. Measurements included pre- a...

SERUM LEVELS OF SEVERAL ORGANOCHLORINE PESTICIDES IN FARMERS CORRESPOND WITH DIETARY EXPOSURE AND LOCAL USE HISTORY

EPA Science Inventory

In response to reported increased cancer risks among farmers, the Agricultural Health Study (AHS) was designed to examine health outcomes and environmental exposures among farm families in the United States. In the pilot phase of the AHS,food,beverage,air,dermal,dust,surface wipe...

Immunodetection of T-2 Metabolites in Rat Urines after Dermal, Oral, or Intramuscular Exposure to T-2 Toxin

DTIC Science & Technology

1988-07-25

laboratory studies, but not useful for evaluation of natural exposure. Several conventional immunoassay techniques based on tritiated ligands (Fontelo. et...1978. Natural occurrence of trichothecenes (nivaienol, deoxynivalenol, T-2) and zearalenone in corn. ExperiLentia 34, 1333-1334. LEE. S. and CHU, F.S

Usage patterns of aromatherapy among the French general population: A descriptive study focusing on dermal exposure.

PubMed

Dornic, N; Ficheux, A S; Roudot, A C; Saboureau, D; Ezzedine, K

2016-04-01

Although likely benefits of aromatherapy are well documented, little is known about essential oils consumption and exposure to molecules present in the oils. The aim of our study was to determine usage patterns of 12 types of essential oils among a quite large panel, sorted per sex and quintile of age from birth to 70. A survey was conducted in September 2014 among 1507 French individuals, selected to build a representative panel of the general population. The key point of our study, apart from the fact that it has never been done among general population, was the focus on dermal exposure. Information about types of essential oils used, skin areas exposed, frequencies and quantities were collected. Our work revealed that some sub-populations could be significantly exposed to molecules of toxicological concern, especially in terms of skin sensitization. This work is the first step to assess human exposure to these molecules, and will help safety authorities and risk managers to protect the population. Copyright © 2016 Elsevier Inc. All rights reserved.

Assessment of field re-entry exposure to pesticides: A dislodgeable foliar residue study.

PubMed

Kasiotis, Konstantinos M; Tsakirakis, Angelos N; Richard Glass, C; Charistou, Agathi N; Anastassiadou, Pelagia; Gerritsen-Ebben, Rianda; Machera, Kyriaki

2017-10-15

A dislodgeable foliar residue study was conducted in greenhouse pepper and tomato on the island of Crete, Greece, following the spray application of an SC insecticide (with active substance (a.s.) tebufenozide) and an EC fungicide (a.s. bupirimate). Furthermore, for the assessment of worker exposure to pesticides - as a result of re-entering the treated crops - a worker dermal exposure study was carried out during the tasks of tying or pruning, which allowed the transfer coefficient values for the specific tasks to be determined. Pesticide residues were analysed with an in house developed and fully validated HPLC-ESI/MS analytical method. The results from the study resulted in transfer coefficient values which were in agreement with current EFSA guideline values in most of the cases with the exception of bupirimate in a tomato greenhouse. In that case, high potential dermal exposure and low dislodgeable foliar residue values were observed, which is thought to be due to the moist leaves collected during sampling and monitoring, which led to greater than expected transfer coefficient values. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

Chronically sun-damaged melanomas express low levels of nuclear glutathione-S-transferase-π: an epidemiological and clinicopathological study in Italy.

PubMed

Campione, Elena; Medda, Emanuela; Paternò, Evelin J; Diluvio, Laura; Ricozzi, Ilaria; Carboni, Isabella; Costanza, Gaetana; Rossi, Piero; Rapanotti, Cristina; Di Stefani, Alessandro; Chimenti, Sergio; Bianchi, Luca; Orlandi, Augusto

2015-01-01

The detoxifying enzyme glutathione-s-transferase pi (GST-π) is present in keratinocytes and melanocytes and exerts a protective role against tumour progression. Melanomas close to melanocytic naevus remnants occur less frequently on sun-exposed areas, whereas solar dermal elastosis, hallmark of chronic sun-damage, characterise melanomas on sun-exposed skin. We evaluated the expression of GST-π in 113 melanomas associated to melanocytic naevus remnants or to solar dermal elastosis, classified according to clinical characteristics, history of sun exposure, histological subtypes and AJCC staging. Chronically sun-damaged melanomas, identified by moderate-severe solar dermal elastosis, showed a lower nuclear GST-π expression and a higher thickness than those related to melanocytic naevus remnants (p < 0.03). Multivariate logistic regression analysis demonstrated that male gender and chronic sun-exposure are independent risk factors significantly associated to melanomas localised on the trunk (OR = 3.36, 95% CI: 1.31-8.65; OR = 5.97, 95% CI: 1.71-20.87). If confirmed on a larger series, lower expression of nuclear GST-π in melanoma cells could represent a possible marker of chronically sun-damaged melanoma pathogenesis.

76 FR 19701 - Glyphosate (N-

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-08

... exposure. It is a mild eye irritant, slight skin irritant, and is not a dermal sensitizer in guinea pigs... those engaged in the following activities: Crop production (NAICS code 111). Animal production (NAICS...

Simulation of urinary excretion of 1-hydroxypyrene in various scenarios of exposure to polycyclic aromatic hydrocarbons with a generic, cross-chemical predictive PBTK-model.

PubMed

Jongeneelen, Frans; ten Berge, Wil

2012-08-01

A physiologically based toxicokinetic (PBTK) model can predict blood and urine concentrations, given a certain exposure scenario of inhalation, dermal and/or oral exposure. The recently developed PBTK-model IndusChemFate is a unified model that mimics the uptake, distribution, metabolism and elimination of a chemical in a reference human of 70 kg. Prediction of the uptake by inhalation is governed by pulmonary exchange to blood. Oral uptake is simulated as a bolus dose that is taken up at a first-order rate. Dermal uptake is estimated by the use of a novel dermal physiologically based module that considers dermal deposition rate and duration of deposition. Moreover, evaporation during skin contact is fully accounted for and related to the volatility of the substance. Partitioning of the chemical and metabolite(s) over blood and tissues is estimated by a Quantitative Structure-Property Relationship (QSPR) algorithm. The aim of this study was to test the generic PBTK-model by comparing measured urinary levels of 1-hydroxypyrene in various inhalation and dermal exposure scenarios with the result of model simulations. In the last three decades, numerous biomonitoring studies of PAH-exposed humans were published that used the bioindicator 1-hydroxypyrene (1-OH-pyrene) in urine. Longitudinal studies that encompass both dosimetry and biomonitoring with repeated sampling in time were selected to test the accuracy of the PBTK-model by comparing the reported concentrations of 1-OHP in urine with the model-predicted values. Two controlled human volunteer studies and three field studies of workers exposed to polycyclic aromatic hydrocarbons (PAH) were included. The urinary pyrene-metabolite levels of a controlled human inhalation study, a transdermal uptake study of bitumen fume, efficacy of respirator use in electrode paste workers, cokery workers in shale oil industry and a longitudinal study of five coke liquefaction workers were compared to the PBTK-predicted values. The simulations showed that the model-predicted concentrations of urinary pyrene and metabolites over time, as well as peak-concentrations and total excreted amount in different exposure scenarios of inhalation and transdermal exposure were in all comparisons within an order of magnitude. The model predicts that only a very small fraction is excreted in urine as parent pyrene and as free 1-OH-pyrene. The predominant urinary metabolite is 1-OH-pyrene-glucuronide. Enterohepatic circulation of 1-OH-pyrene-glucuronide seems the reason of the delayed release from the body. It appeared that urinary excretion of pyrene and pyrene-metabolites in humans is predictable with the PBTK-model. The model outcomes have a satisfying accuracy for early testing, in so-called 1st tier simulations and in range finding. This newly developed generic PBTK-model IndusChemFate is a tool that can be used to do early explorations of the significance of uptake of pyrene in the human body following industrial or environmental exposure scenarios. And it can be used to optimize the sampling time and urine sampling frequency of a biomonitoring program.

Toxicology of dimethyl and monomethyl derivatives of acetamide and formamide: a second update.

PubMed

Kennedy, Gerald L

2012-11-01

Dimethylacetamide (DMAC) and dimethylformamide (DMF) continue to be important, widely used solvents involved in a wide variety of industrial applications. As liquids with relatively low vapor pressures, contact with both the integumentary and respiratory systems is the main source of human exposure. Although airborne control levels for the workplace have been established and industrial hygiene practices to limit dermal contact have been put in place, use of these chemicals has been associated with occupational illness, mainly in Asia where new and expanded uses have led to overexposures. Thus an update of the basic toxicology data including tables indicating the dose/exposure response characteristics of both DMAC and DMF is currently important. Both chemicals are similar from a toxicology perspective. Human experience has generally shown the materials to be without adverse effect except under conditions where airborne and dermal controls were not properly applied. The use of urinary metabolite monitoring has successfully been employed to measure integrated dermal and inhalation worker exposure. The chemicals are not particularly toxic following acute exposure but high doses can produce damage to the liver, the organ which is first affected by these two chemicals. Repeated dose/exposure studies have characterized both the targets of toxicity and the doses required to produce changes by various routes of exposure. Higher doses of these materials can produce changes in developing systems, infrequently in experiments at doses in which the maternal animal is unaffected, thus care needs to be taken when exposures are to women of child-bearing age. The chemicals appear to be low in genetic activity and inhalation exposures have not shown the materials to produce tumors in rodents except with DMF in a situation in which aerosol formation was encountered. This presentation extends the two previous reviews and, like those, includes updated information on acetamide and formamide and their monomethyl derivatives as well as the commercially important DMAC and DMF. Since a large portion of the newer information deals with effects in humans and biomonitoring, these sections are presented at the start of this review.

Toxicity resulting from exposure to oven cleaners as reported to the UK National Poisons Information Service (NPIS) from 2009 to 2015.

PubMed

Day, Rachael C; Bradberry, Sally M; Sandilands, Euan A; Thomas, Simon H L; Thompson, John P; Vale, J Allister

2017-08-01

Oven cleaning products contain corrosive substances, typically sodium or potassium hydroxide. To determine the reported toxicity from exposure to oven cleaning products. Telephone enquiries to the UK National Poisons Information Service regarding oven cleaning products were analysed retrospectively for the period January 2009 to December 2015. There were 796 enquiries relating to 780 patients. Ninety-six percent of the products involved in the reported exposures contained sodium hydroxide and/or potassium hydroxide. Ingestion alone (n = 285) or skin contact alone (n = 208) accounted for the majority of cases; inhalation alone (n = 101), eye contact alone (n = 97), and multiple routes of exposure (n = 89) accounted for the remainder. Ninety-five percent of patients exposed by inhalation, 94% exposed dermally and 85% reporting eye exposure, developed features of toxicity. Patients exposed by multiple routes developed symptoms in 70% of cases. Only 103 of the 285 patients ingested oven cleaner directly, whereas 182 patients ingested food they considered to have been contaminated with oven cleaner. In 100 of the 103 direct ingestions where the features and World Health Organisation/International Programme on Chemical Safety/European Commission/European Association of Poison Centres and Clinical Toxicologists Poisoning Severity Score were known, 56 reported symptoms which were minor in 51 cases. The most common features following ingestion were vomiting (n = 26), abdominal pain (n = 22) or pharyngitis (n = 15). Skin burns (n = 91) predominantly involving the hands or arms, occurred in 44% of dermal exposures. Following inhalation, patients frequently developed respiratory features (n = 52) including coughing and chest pain/tightness. Eye pain (n = 43) and conjunctivitis (n = 33) commonly occurred following ocular exposure. Most (71%) patients exposed to an oven cleaner irrespective of the route of exposure developed features of toxicity, though in most cases only minor features developed; moderate or severe features ensued in ∼4%. Those patients exposed dermally, ophthalmically or by inhalation developed features more frequently (≥85%) than those who ingested a product directly (56%).

First tier modeling of consumer dermal exposure to substances in consumer articles under REACH: a quantitative evaluation of the ECETOC TRA for consumers tool.

PubMed

Delmaar, J E; Bokkers, B G H; ter Burg, W; van Engelen, J G M

2013-02-01

The demonstration of safe use of chemicals in consumer products, as required under REACH, is proposed to follow a tiered process. In the first tier, simple conservative methods and assumptions should be made to quickly verify whether risks for a particular use are expected. The ECETOC TRA Consumer Exposure Tool was developed to assist in first tier risk assessments for substances in consumer products. The ECETOC TRA is not a prioritization tool, but is meant as a first screening. Therefore, the exposure assessment needs to cover all products/articles in a specific category. For the assessment of the dermal exposure for substances in articles, ECETOC TRA uses the concept of a 'contact layer', a hypothetical layer that limits the exposure to a substance contained in the product. For each product/article category, ECETOC TRA proposes default values for the thickness of this contact layer. As relevant experimental exposure data is currently lacking, default values are based on expert judgment alone. In this paper it is verified whether this concept meets the requirement of being a conservative exposure evaluation method. This is done by confronting the ECETOC TRA expert judgment based predictions with a mechanistic emission model, based on the well established theory of diffusion of substances in materials. Diffusion models have been applied and tested in many applications of emission modeling. Experimentally determined input data for a number of material and substance combinations are available. The estimated emissions provide information on the range of emissions that could occur in reality. First tier tools such as ECETOC TRA tool are required to cover all products/articles in a category and to provide estimates that are at least as high as is expected on the basis of current scientific knowledge. Since this was not the case, it is concluded that the ECETOC TRA does not provide a proper conservative estimation method for the dermal exposure to articles. An alternative method was proposed. Copyright © 2012 Elsevier Inc. All rights reserved.

Investigations of immunotoxicity and allergic potential induced by topical application of triclosan in mice

PubMed Central

Anderson, Stacey E.; Meade, B. Jean; Long, Carrie M.; Lukomska, Ewa; Marshall, Nikki B.

2016-01-01

Triclosan is an antimicrobial chemical commonly used occupationally and by the general public. Using select immune function assays, the purpose of these studies was to evaluate the immunotoxicity of triclosan following dermal exposure using a murine model. Triclosan was not identified to be a sensitizer in the murine local lymph node assay (LLNA) when tested at concentrations ranging from 0.75–3.0%. Following a 28-day exposure, triclosan produced a significant increase in liver weight at concentrations of ≥ 1.5%. Exposure to the high dose (3.0%) also produced a significant increase in spleen weights and number of platelets. The absolute number of B-cells, T-cells, dendritic cells and NK cells were significantly increased in the skin draining lymph node, but not the spleen. An increase in the frequency of dendritic cells was also observed in the lymph node following exposure to 3.0% triclosan. The IgM antibody response to sheep red blood cells (SRBC) was significantly increased at 0.75% – but not at the higher concentrations – in the spleen and serum. These results demonstrate that dermal exposure to triclosan induces stimulation of the immune system in a murine model and raise concerns about potential human exposure. PMID:25812624

Risk assessment for consumer exposure to toluene diisocyanate (TDI) derived from polyurethane flexible foam.

PubMed

Arnold, Scott M; Collins, Michael A; Graham, Cynthia; Jolly, Athena T; Parod, Ralph J; Poole, Alan; Schupp, Thomas; Shiotsuka, Ronald N; Woolhiser, Michael R

2012-12-01

Polyurethanes (PU) are polymers made from diisocyanates and polyols for a variety of consumer products. It has been suggested that PU foam may contain trace amounts of residual toluene diisocyanate (TDI) monomers and present a health risk. To address this concern, the exposure scenario and health risks posed by sleeping on a PU foam mattress were evaluated. Toxicity benchmarks for key non-cancer endpoints (i.e., irritation, sensitization, respiratory tract effects) were determined by dividing points of departure by uncertainty factors. The cancer benchmark was derived using the USEPA Benchmark Dose Software. Results of previous migration and emission data of TDI from PU foam were combined with conservative exposure factors to calculate upper-bound dermal and inhalation exposures to TDI as well as a lifetime average daily dose to TDI from dermal exposure. For each non-cancer endpoint, the toxicity benchmark was divided by the calculated exposure to determine the margin of safety (MOS), which ranged from 200 (respiratory tract) to 3×10(6) (irritation). Although available data indicate TDI is not carcinogenic, a theoretical excess cancer risk (1×10(-7)) was calculated. We conclude from this assessment that sleeping on a PU foam mattress does not pose TDI-related health risks to consumers. Copyright © 2012 Elsevier Inc. All rights reserved.

46 CFR 197.555 - Personal protective clothing and equipment.

Code of Federal Regulations, 2013 CFR

2013-10-01

... SAFETY AND HEALTH STANDARDS GENERAL PROVISIONS Benzene § 197.555 Personal protective clothing and..., tight-fitting eye goggles to limit dermal exposure to, and prevent eye contact with, liquid benzene. ...

46 CFR 197.555 - Personal protective clothing and equipment.

Code of Federal Regulations, 2012 CFR

2012-10-01

... SAFETY AND HEALTH STANDARDS GENERAL PROVISIONS Benzene § 197.555 Personal protective clothing and..., tight-fitting eye goggles to limit dermal exposure to, and prevent eye contact with, liquid benzene. ...

46 CFR 197.555 - Personal protective clothing and equipment.

Code of Federal Regulations, 2014 CFR

2014-10-01

... SAFETY AND HEALTH STANDARDS GENERAL PROVISIONS Benzene § 197.555 Personal protective clothing and..., tight-fitting eye goggles to limit dermal exposure to, and prevent eye contact with, liquid benzene. ...

EVALUATION OF THE EFFECTIVENESS OF COATINGS IN REDUCING DISLODGEABLE ARSENIC, CHROMIUM, AND COPPER FROM CCA TREATED WOOD, INTERIM DATA REPORT

EPA Science Inventory

EPA is approximately 20 months into a project to evaluate the performance of wood coatings as a way to prevent arsenic, chromium and copper exposure from the surfaces of CCA treated wood. Potential dermal exposure, as measured by wipe sampling dislodgeable CCA chemical from wood ...

OPPT workplan risk assessment Methylene Chloride (dichloromethane; CASRN 75-09-2) and N-Methylpyrrolidone (NMP; CASRN 872-50-4)

EPA Science Inventory

These assessments will focus on the use of DCM and NMP in paint stripping. NMP exposures scenarios for this use result in inhalation and dermal exposure to consumers and workers. The low concern for environmental effects of NMP will be discussed in the assessment. In the case of ...

75 FR 4274 - Novaluron; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-27

... at 0.50 parts per million (ppm); Swiss chard at 12 ppm; bean, snap, succulent at 0.60 ppm; bean, dry...; bean, dry, seed at 0.30 ppm; and Swiss chard at 12 ppm. EPA's assessment of exposures and risks.... Novaluron has low acute toxicity via the oral, dermal and inhalation routes of exposure. It is not an eye or...

EVALUATING COMMERCIALLY AVAILABLE DERMAL WIPES, COTTON SUITES, AND ALTERNATIVE URINARY COLLECTION MATERIALS FOR PESTICIDE SAMPLING FROM INFANTS

EPA Science Inventory

As the Human Exposure Program focuses on the exposure of children to pesticides, there are concerns about the effect, or perceived effect, of components of the sampling procedure on the health and well-being of the infant and the ability to collect pesticide residues.

One...

Linking a dermal permeation and an inhalation model to a simple pharmacokinetic model to study airborne exposure to di(n-butyl) phthalate.

PubMed

Lorber, Matthew; Weschler, Charles J; Morrison, Glenn; Bekö, Gabriel; Gong, Mengyan; Koch, Holger M; Salthammer, Tunga; Schripp, Tobias; Toftum, Jørn; Clausen, Geo

2017-11-01

Six males clad only in shorts were exposed to high levels of airborne di(n-butyl) phthalate (DnBP) and diethyl phthalate (DEP) in chamber experiments conducted in 2014. In two 6 h sessions, the subjects were exposed only dermally while breathing clean air from a hood, and both dermally and via inhalation when exposed without a hood. Full urine samples were taken before, during, and for 48 h after leaving the chamber and measured for key DnBP and DEP metabolites. The data clearly demonstrated high levels of DnBP and DEP metabolite excretions while in the chamber and during the first 24 h once leaving the chamber under both conditions. The data for DnBP were used in a modeling exercise linking dose models for inhalation and transdermal permeation with a simple pharmacokinetic model that predicted timing and mass of metabolite excretions. These models were developed and calibrated independent of these experiments. Tests included modeling of the "hood-on" (transdermal penetration only), "hood-off" (both inhalation and transdermal) scenarios, and a derived "inhalation-only" scenario. Results showed that the linked model tended to duplicate the pattern of excretion with regard to timing of peaks, decline of concentrations over time, and the ratio of DnBP metabolites. However, the transdermal model tended to overpredict penetration of DnBP such that predictions of metabolite excretions were between 1.1 and 4.5 times higher than the cumulative excretion of DnBP metabolites over the 54 h of the simulation. A similar overprediction was not seen for the "inhalation-only" simulations. Possible explanations and model refinements for these overpredictions are discussed. In a demonstration of the linked model designed to characterize general population exposures to typical airborne indoor concentrations of DnBP in the United States, it was estimated that up to one-quarter of total exposures could be due to inhalation and dermal uptake.

78 FR 13257 - Pyraflufen-ethyl; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-27

... relatively low acute toxicity from oral, dermal, and inhalation exposure. It produces moderate eye [[Page.... However, default processing factors were used for dry potatoes (6.5X), peanut butter (1.89X), dried beef...

Human health risk analysis from disinfection by-products (DBPs) in drinking and bathing water of some Indian cities

PubMed Central

2014-01-01

Background Human health risk assessment from exposure to disinfection by-products (DBPs) during drinking and bathing water vary from country to country as per life expectancy, body mass index, water consumption pattern and individual concentration of DBPs component, etc. Methods Present study considered average direct water intake per person for adult males and females as 4 & 3 L/day, respectively as per Indian literature for risk evaluation from another component of pollutant. While other important factor like average life expectancy, body weight & body surface area for male and female were considered 64 & 67 years, 51.9 & 45.4 Kg and 1.54 & 1.38 m2 respectively as per Indian Council of Medical Research and WHO report. The corresponding lifetime cancer risk of the formed THMs to human beings was estimated by the USEPA and IRIS method as per Indian population. Results The total cancer risk reached 8.99 E-04 and 8.92 E-04 for males and females, respectively, the highest risk from THMs seems to be from the inhalation route followed by ingestion and dermal contacts. Conclusions The multipath way evaluations of lifetime cancer risks for THMs exposure through ingestion, dermal absorption, and inhalation exposure were examined at the highest degree of danger. Results reveals that water containing THMs of the selected water treatment plant of the eastern part of India was unsafe in terms of risk evaluation through inhalation and ingestion, while dermal route of risk was found very close to permissible limit of USEPA. Sensitivity analysis shows that every input parameter is sole responsible for total risk potential, whereas exposure duration playing important role for estimation of total risk. PMID:24872885

Human skin permeation of emerging mycotoxins (beauvericin and enniatins).

PubMed

Taevernier, Lien; Veryser, Lieselotte; Roche, Nathalie; Peremans, Kathelijne; Burvenich, Christian; Delesalle, Catherine; De Spiegeleer, Bart

2016-01-01

Currently, dermal exposure data of cyclic depsipeptide mycotoxins are completely absent. There is a lack of understanding about the local skin and systemic kinetics and effects, despite their widespread skin contact and intrinsic hazard. Therefore, we provide a quantitative characterisation of their dermal kinetics. The emerging mycotoxins enniatins (ENNs) and beauvericin (BEA) were used as model compounds and their transdermal kinetics were quantitatively evaluated, using intact and damaged human skin in an in vitro Franz diffusion cell set-up and ultra high-performance liquid chromatography (UHPLC)-MS analytics. We demonstrated that all investigated mycotoxins are able to penetrate through the skin. ENN B showed the highest permeation (kp,v=9.44 × 10(-6) cm/h), whereas BEA showed the lowest (kp,v=2.35 × 10(-6) cm/h) and the other ENNs ranging in between. Combining these values with experimentally determined solubility data, Jmax values ranging from 0.02 to 0.35 μg/(cm(2) h) for intact skin and from 0.07 to 1.11 μg/(cm(2) h) for damaged skin were obtained. These were used to determine the daily dermal exposure (DDE) in a worst-case scenario. On the other hand, DDE's for a typical occupational scenario were calculated based on real-life mycotoxin concentrations for the industrial exposure of food-related workers. In the latter case, for contact with intact human skin, DDE's up to 0.0870 ng/(kg BW × day) for ENN A were calculated, whereas for impaired skin barrier this can even rise up to 0.3209 ng/(kg BW × day) for ENN B1. This knowledge is needed for the risk assessment after skin exposure of contaminated food, feed, indoor surfaces and airborne particles with mycotoxins.

Inhalation and dermal exposure to eight antineoplastic drugs in an industrial laundry facility.

PubMed

Fransman, Wouter; Huizer, Daan; Tuerk, Jochen; Kromhout, Hans

2007-04-01

The aims of the study were to quantify levels of dermal and inhalation exposure to antineoplastic drugs in an industrial laundry service in the Netherlands and to test the removal efficiency of the washing procedure for removal of antineoplastic drugs. During four workdays dermal and inhalation exposure to eight frequently used antineoplastic drugs (cyclophosphamide, ifosfamide, methotrexate, 5-fluorouracil, etoposide, cytarabine, gemcitabine and chlorambucil) were measured for all job titles involved in handling unwashed laundry. To test the removal efficiency of the washing procedure, 10 x 10 cm sections were excised before and after the washing procedure. These sections were taken from 15 bed sheets that were collected in hospitals of patients who were treated with one of the selected antineoplastic drugs. During none of the four measurement days, detectable levels of any of the eight antineoplastic drugs (cyclophosphamide, ifosfamide, methotrexate, 5-fluorouracil, etoposide, cytarabine, gemcitabine, or chlorambucil) were found on workers' skin of hands or in any of the air samples. Only four out of the 15 bed sheets from patients that were treated with antineoplastic drugs appeared to be contaminated with detectable levels of antineoplastic drugs before the washing procedure (range 13.0-3,060 ng/100 cm(2)). After the pre-washing and after the complete washing procedure, no detectable levels of any of the eight antineoplastic drugs were found anymore in the selected bed sheets. The implementation of guidelines for working with antineoplastic drugs seems to be successful in reducing exposure to antineoplastic drugs of workers in this laundry facility to an acceptable, non-detectable level and to remove antineoplastic drug contamination from bed linen.

Selective Susceptibility of Human Skin Antigen Presenting Cells to Productive Dengue Virus Infection

PubMed Central

Cerny, Daniela; Haniffa, Muzlifah; Shin, Amanda; Bigliardi, Paul; Tan, Bien Keem; Lee, Bernett; Poidinger, Michael; Tan, Ern Yu; Ginhoux, Florent; Fink, Katja

2014-01-01

Dengue is a growing global concern with 390 million people infected each year. Dengue virus (DENV) is transmitted by mosquitoes, thus host cells in the skin are the first point of contact with the virus. Human skin contains several populations of antigen-presenting cells which could drive the immune response to DENV in vivo: epidermal Langerhans cells (LCs), three populations of dermal dendritic cells (DCs), and macrophages. Using samples of normal human skin we detected productive infection of CD14+ and CD1c+ DCs, LCs and dermal macrophages, which was independent of DC-SIGN expression. LCs produced the highest viral titers and were less sensitive to IFN-β. Nanostring gene expression data showed significant up-regulation of IFN-β, STAT-1 and CCL5 upon viral exposure in susceptible DC populations. In mice infected intra-dermally with DENV we detected parallel populations of infected DCs originating from the dermis and migrating to the skin-draining lymph nodes. Therefore dermal DCs may simultaneously facilitate systemic spread of DENV and initiate the adaptive anti-viral immune response. PMID:25474532

Contaminated soils (II): in vitro dermal absorption of nickel (Ni-63) and mercury (Hg-203) in human skin.

PubMed

Moody, Richard P; Joncas, Julie; Richardson, Mark; Petrovic, Sanya; Chu, Ih

2009-01-01

Dermal absorption of heavy metal soil contaminants was tested in vitro with chloride salts of radioactive nickel (Ni-63) and mercury (Hg-203). Aqueous soil suspensions, spiked with either Ni-63 or Hg-203, were applied to fresh viable human breast skin tissue in Bronaugh diffusion cells perfused with Hanks HEPES buffered (pH 7.4) receptor containing 4% bovine serum albumin (BSA). Receptor fractions were collected every 6 h for 24 h when skin was soap washed. Tests were conducted concurrently in triplicate with and without soil for each skin specimen. Mean percent dermal absorption including the skin depot for Ni-63 was 1 and 22.8% with and without soil, respectively, while for Hg-203, values of 46.6 and 78.3% were obtained. Excluding the skin depot and considering only absorption in receptor, there was 0.5 and 1.8% absorption of Ni-63 with and without soil, respectively, and 1.5 and 1.4% for Hg-203. The potential bioavailability of the skin depot is discussed in relation to dermal exposure to these metals in contaminated soil.

Biomarker Discovery After Occupational Exposure To Volatile Organic Compounds And Aerosols In F-15 and C-130 Flight Line Crews: Examination of ProInflammatory Cytokines in Serum

DTIC Science & Technology

2014-08-29

about exposure to spills of any kind, direct dermal exposure to jet fuel or solvent or other exposures such as cleaning fluids and smoking (if a smoker ...additives, may influence toxicity during exposure. JP-8 was found to be non -irritating in the rabbit primary eye irritation test (Smith et al...1981; Kinkead et al., 1992a). Results in the corresponding rabbit skin irritation test ranged from non -irritating (Smith et al., 1981; Wolfe et al

The influence of water mixtures on the dermal absorption of glycol ethers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Traynor, Matthew J.; Wilkinson, Simon C.; Williams, Faith M.

2007-01-15

Glycol ethers are solvents widely used alone and as mixtures in industrial and household products. Some glycol ethers have been shown to have a range of toxic effects in humans following absorption and metabolism to their aldehyde and acid metabolites. This study assessed the influence of water mixtures on the dermal absorption of butoxyethanol and ethoxyethanol in vitro through human skin. Butoxyethanol penetrated human skin up to sixfold more rapidly from aqueous solution (50%, 450 mg/ml) than from the neat solvent. Similarly penetration of ethoxyethanol was increased threefold in the presence of water (50%, 697 mg/ml). There was a correspondingmore » increase in apparent permeability coefficient as the glycol ether concentration in water decreased. The maximum penetration rate of water also increased in the presence of both glycol ethers. Absorption through a synthetic membrane obeyed Fick's Law and absorption through rat skin showed a similar profile to human skin but with a lesser effect. The mechanisms for this phenomenon involves disruption of the stratum corneum lipid bilayer by desiccation by neat glycol ether micelles, hydration with water mixtures and the physicochemical properties of the glycol ether-water mixtures. Full elucidation of the profile of absorption of glycol ethers from mixtures is required for risk assessment of dermal exposure. This work supports the view that risk assessments for dermal contact scenarios should ideally be based on absorption data obtained for the relevant formulation or mixture and exposure scenario and that absorption derived from permeability coefficients may be inappropriate for water-miscible solvents.« less

Understanding Factors that Influence Protective Glove Use among Automotive Spray Painters

PubMed Central

Ceballos, Diana; Reeb-Whitaker, Carolyn; Glazer, Patricia; Murphy-Robinson, Helen; Yost, Michael

2017-01-01

Dermal contact with isocyanate-based coatings may lead to systemic respiratory sensitization. The most common isocyanates found in sprayed automotive coatings are monomeric and oligomeric 1,6-hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI). Most spray painters use thin (4–5 mil) latex gloves that are not effective at preventing dermal exposures when spraying isocyanate paints. Personal interviews with collision repair industry personnel and focus groups with spray painters were held to characterize risk awareness, to examine perceptions and challenges concerning protective glove use and selection, and to generate ideas for protective glove use interventions. The most popular gloves among spray painters were thin (4–5 mil) and thick (14 mil) latex. We found that medium to thick (6–8 mil) nitrile were not always perceived as comfortable and were expected to be more expensive than thin (4–5 mil) latex gloves. Of concern is the users’ difficulty to distinguish between nitrile and latex gloves; latex gloves are now sold in different colors including blue, which has traditionally been associated with nitrile gloves. Even though spray painters were familiar with the health hazards related to working with isocyanate paints; most were not always aware that dermal exposure to isocyanates could contribute to the development of occupational asthma. There is a need for more research to identify dermal materials that are protective against sprayed automotive coatings. Automotive spray painters and their employers need to be educated in the selection and use of protective gloves, specifically on attributes such as glove material, color, and thickness. PMID:24215135

Safety Evaluation of Silk Protein Film (A Novel Wound Healing Agent) in Terms of Acute Dermal Toxicity, Acute Dermal Irritation and Skin Sensitization

PubMed Central

Padol, Amol R.; Jayakumar, K.; Shridhar, N. B.; Narayana Swamy, H. D.; Narayana Swamy, M.; Mohan, K.

2011-01-01

Acute dermal toxicity study was conducted in rats. The parameters studied were body weight, serum biochemistry and gross pathology. The animals were also observed for clinical signs and mortality after the application of test film. The dermal irritation potential of silk protein film was examined using Draize test. In the initial test, three test patches were applied sequentially for 3 min, 1 and 4 hours, respectively, and skin reaction was graded. The irritant or negative response was confirmed using two additional animals, each with one patch, for an exposure period of 4 hours. The responses were scored at 1, 24, 48 and 72 hours after the patch removal. Skin sensitization study was conducted according to Buehler test in guinea pigs, in which on day 0, 7 and 14, the animals were exposed to test material for 6 hours (Induction phase) and on day 28, the animals were exposed for a period of 24 hours (Challenge phase). The skin was observed and recorded at 24 and 48 hours after the patch removal. In acute dermal toxicity study, the rats dermally treated with silk film did not show any abnormal clinical signs and the body weight, biochemical parameters and gross pathological observations were not significantly different from the control group. In acute dermal irritation study, the treated rabbits showed no signs of erythema, edema and eschar, and the scoring was given as “0” for all time points of observations according to Draize scoring system. In skin sensitization study, there were no skin reactions 24 and 48 hours after the removal of challenge patch, which was scored “0” based on Magnusson/Kligman grading scale. PMID:21430915

Effect of Skin Protection and Skin Irritation on the Internal Exposure to Carbon Disulfide in Employees of the Viscose Industry.

PubMed

Kilo, Sonja; Zonnur, Nina; Uter, Wolfgang; Göen, Thomas; Drexler, Hans

2015-10-01

Occupational exposure to carbon disulfide (CS2) leads to inhalative and dermal uptake and thereby to internal exposure. In order to prevent occupational contact dermatitis, gloves and skin protection creams are used at the workplace. The aim of the study was the evaluation of the influence of personal skin protection and irritation on the internal exposure to CS2 of employees in the viscose industry. One hundred and eighty-two male CS2-exposed employees were included in the study and were examined regarding working conditions, use of personal protective measures und skin status. Personal air monitoring and biological monitoring was performed and the 'relative internal exposure' (RIE, internal exposure in relation to external exposure) calculated. A multiple regression analysis calculated the influence of skin protection and irritation on CS2 uptake. Usage of skin protection creams and gloves (and both in combination) while working was associated with a significantly higher RIE indicating a higher dermal penetration of CS2. Equally, irritated skin and younger age was associated with a higher internal burden. Gloves and skin protection creams are useful for preventing occupational skin diseases. However, when handling skin-resorptive substances like CS2, they can increase internal exposure or skin irritation. Therefore, we recommend the careful consideration of benefits and risks of protective creams and gloves at the workplace. © The Author 2015. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Contributing Factors for Acute Illness/Injury from Childhood Pesticide Exposure in North Carolina, USA, 2007–2013

PubMed Central

Barros, Nirmalla; Langley, Ricky; Buhler, Wayne; Brantham, Kelly

2016-01-01

Between 2007 and 2013, there were 685 events with evidence of a relationship between pesticide exposure and acute illness/injury among persons less than 18 years old in North Carolina (United States). Median age of children affected was 4.3 years (range: 0.2–17.9). Distribution by gender was similar across all age groups. One fatality and four high severity events were observed. The greatest proportion (42%) of events had ocular exposures, followed by dermal (25%) and inhalation (18%) exposures. When more than one route of exposure occurred, dermal and ocular routes were the most common (46%). Almost all events took place indoors and 32 events involved contact with pets. Insecticides (53%) and insect repellants (31%) were the most frequent agents contributing to these events. Manual application of pesticides contributed to the greatest number of events (25%), while application through a pressurized can and use of a trigger pump were involved in 21% and 15% of events, respectively. Additional contributors were due to inappropriate storage of pesticides and improper use of the pesticide. These contributing factors can be removed or minimized if pesticides are stored outside the residence or out of the reach of children and pets, and adequate ventilation is ensured whenever pesticides are applied. PMID:29051410

Local and systemic toxicity of JP-8 from cutaneous exposures.

PubMed

McDougal, James N; Rogers, James V

2004-04-01

Jet propellant-8 (JP-8) jet fuel is a version of commercial jet fuel, Jet A, and is a complex mixture of primarily aliphatic (but also aromatic) hydrocarbons that varies in composition from batch to batch. There is potential for dermal exposure to jet fuels with personnel involved in aircraft refueling and maintenance operations as well as ground personnel. Cutaneous exposures have the potential to cause skin irritation, sensitization or skin cancer. JP-8 has been shown to be irritating and causes molecular changes in the skin of laboratory animals. The mechanisms of some of these effects have been investigated in intact skin and cultured skin cells. Hydrocarbons have also been shown to cause skin cancer with repeated application to the skin. Additionally, there is concern about systemic toxicity from dermal exposures to jet fuels, such as JP-8. Assessing risks from systemic absorption of hydrocarbon components is complex because most of the components are present in the mixture in small quantities (less than 1%). The effect of the fuel as a vehicle, different rates of penetration through the skin and different target organ toxicities all complicate the assessment of the hazards of cutaneous exposures. The purpose of this manuscript is to review studies of local and systemic toxicity of JP-8.

Sampling the stratum corneum for toxic chemicals.

PubMed

Coman, Garrett; Blickenstaff, Nicholas R; Blattner, Collin M; Andersen, Rosa; Maibach, Howard I

2014-01-01

Dermal exposure is an important pathway in environmental health. Exposure comes from contaminated water, soil, treated surfaces, textiles, aerosolized chemicals, and agricultural products. It can occur in homes, schools, play areas, and work settings in the form of industrial sources, consumer products, or hazardous wastes. Dermal exposure is most likely to occur through contact with liquids, water, soil, sediment, and contaminated surfaces. The ability to detect and measure exposure to toxic materials on the skin is an important environmental health issue. The stratum corneum is the skin's first and principal barrier layer of protection from the outside world. It has a complex structure that can effectively protect against a wide variety of physical, chemical, and biological contaminants. However, there are a variety of chemical agents that can damage the stratum corneum and the underlying epidermis, dermis and subcutis, and/or enter systemic circulation through the skin. There are numerous ways of sampling the stratum corneum for these toxic materials like abrasion techniques, biopsy, suction blistering, imaging, washing, wipe sampling, tape stripping, and spot testing. Selecting a method likely depends on the particular needs of the situation. Hence, there is a need to review practical considerations for their use in sampling the stratum corneum for toxins.

Occupational safety considerations with hydrazine fuels

NASA Technical Reports Server (NTRS)

Clewell, H. J.; Haddad, T. S.; George, M. E.; Mcdougal, J. N.; Andersen, M. E.

1992-01-01

A simple pharmacokinetic model and a specially designed dermal vapor exposure chamber which provides respiratory protection were used to determine the rate of penetration of hydrazine and 1,1-dimethylhydrazine (UDMH) vapor through the skin of rats. Parameters for the pharmacokinetic model were determined from intravenous and inhalation exposure data. The model was then used to estimate the skin permeation coefficient for hydrazine or UDMH vapor from the dermal-vapor exposure data. This analysis indicates that UDMH vapor has a relatively high permeability through skin (0.7 cm/hr), a value somewhat higher than was obtained for hydrazine by the same procedure (0.09 cm/hr). Based on these skin permeability results, a skin-only vapor exposure limit giving protection equivalent to the inhalation Threshold Limit Value (TLV) could be calculated. The current TLV's for UDMH and hydrazine are 0.5 and 0.1 ppm, respectively. The corresponding skin-only TLV equivalents, for personnel wearing respiratory protection, are 32 ppm for UDMH and 48 ppm for hydrazine. Should the proposed lowering to the TLV's for these compounds to 0.01 ppm be adopted, the equivalent skin-only TLV's would become 0.64 ppm for UDMH and 4.8 for hydrazine.

Socioeconomic status and exposure to disinfection by-products in drinking water in Spain.

PubMed

Castaño-Vinyals, Gemma; Cantor, Kenneth P; Villanueva, Cristina M; Tardon, Adonina; Garcia-Closas, Reina; Serra, Consol; Carrato, Alfredo; Malats, Núria; Rothman, Nathaniel; Silverman, Debra; Kogevinas, Manolis

2011-03-16

Disinfection by-products in drinking water are chemical contaminants that have been associated with cancer and other adverse effects. Exposure occurs from consumption of tap water, inhalation and dermal absorption. We determined the relationship between socioeconomic status and exposure to disinfection by-products in 1271 controls from a multicentric bladder cancer case-control study in Spain. Information on lifetime drinking water sources, swimming pool attendance, showering-bathing practices, and socioeconomic status (education, income) was collected through personal interviews. The most highly educated subjects consumed less tap water (57%) and more bottled water (33%) than illiterate subjects (69% and 17% respectively, p-value = 0.003). These differences became wider in recent time periods. The time spent bathing or showering was positively correlated with attained educational level (p < 0.001). Swimming pool attendance was more frequent among highly educated subjects compared to the illiterate (odds ratio = 3.4; 95% confidence interval 1.6-7.3). The most highly educated subjects were less exposed to chlorination by-products through ingestion but more exposed through dermal contact and inhalation in pools and showers/baths. Health risk perceptions and economic capacity may affect patterns of water consumption that can result in differences in exposure to water contaminants.

Impact of Fire Suit Ensembles on Firefighter PAH Exposures as Assessed by Skin Deposition and Urinary Biomarkers.

PubMed

Wingfors, Håkan; Nyholm, Jenny Rattfelt; Magnusson, Roger; Wijkmark, Cecilia Hammar

2018-02-13

Over the past 10 years, a number of safety measures for reducing firefighters' exposure to combustion particles have been introduced in Sweden. The most important measure was the reduction in the time firefighters wear suits and handle contaminated equipment after turn-outs involving smoke diving. This study was divided into two parts, those being to investigate the level of protection obtained by multiple garment layers and to assess exposure during a standardized smoke diving exercise. First, realistic work protection factors (WPFs) were calculated by comparing air concentrations of the full suite of gaseous and particle-bound polycyclic aromatic hydrocarbons (PAHs) inside and outside structural ensembles, including jacket and thick base layer, during a tough fire extinguishing exercise using wood as the fuel. Second, during a standardized smoke diving exercise, exposure was assessed by measuring PAH skin deposition and levels of eight urinary PAH metabolites in 20 volunteer student firefighters before and after the exercise. The average WPF for the sum of 22 PAHs was 146 ± 33 suggesting a relatively high protective capacity but also indicating a substantial enrichment of contaminants with a risk of prolonged dermal exposure. Accordingly, in the second exercise, the median levels of skin-deposited Σ14-PAHs and urinary 1-hydroxypyrene significantly increased 5-fold (21 to 99 ng/wipe) and 8-fold (0.14 to 1.1 µmol mol-1 creatinine), respectively, post exposure. Among the PAH metabolites investigated, 1-hydroxypyrene proved to be the most useful indicator of exposure, with significantly elevated urinary levels at both 6 h and 20 h after the exercise and with the strongest correlation to dermal exposure. Metabolites from two-ring and three-ring PAHs were eliminated faster while levels of 3-hydroxy-benzo[a]pyrene did not meet the detection criteria. The results from correlation studies indicated that dermal uptake was a major route of exposure in accordance with previous findings. To summarize, this study shows that some of the newly adopted protective measures were correctly implemented, and should continue to be followed and be more widely adopted. © The Author(s) 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Migration of Beryllium via Multiple Exposure Pathways among Work Processes in Four Different Facilities.

PubMed

Armstrong, Jenna L; Day, Gregory A; Park, Ji Young; Stefaniak, Aleksandr B; Stanton, Marcia L; Deubner, David C; Kent, Michael S; Schuler, Christine R; Virji, M Abbas

2014-01-01

Inhalation of beryllium is associated with the development of sensitization; however, dermal exposure may also be important. The primary aim of this study was to elucidate relationships among exposure pathways in four different manufacturing and finishing facilities. Secondary aims were to identify jobs with increased levels of beryllium in air, on skin, and on surfaces; identify potential discrepancies in exposure pathways, and determine if these are related to jobs with previously identified risk. Beryllium was measured in air, on cotton gloves, and on work surfaces. Summary statistics were calculated and correlations among all three measurement types were examined at the facility and job level. Exposure ranking strategies were used to identify jobs with higher exposures. The highest air, glove, and surface measurements were observed in beryllium metal production and beryllium oxide ceramics manufacturing jobs that involved hot processes and handling powders. Two finishing and distribution facilities that handle solid alloy products had lower exposures than the primary production facilities, and there were differences observed among jobs. For all facilities combined, strong correlations were found between air-surface (rp ≥ 0.77), glove-surface (rp ≥ 0.76), and air-glove measurements (rp ≥ 0.69). In jobs where higher risk of beryllium sensitization or disease has been reported, exposure levels for all three measurement types were higher than in jobs with lower risk, though they were not the highest. Some jobs with low air concentrations had higher levels of beryllium on glove and surface wipe samples, suggesting a need to further evaluate the causes of the discrepant levels. Although such correlations provide insight on where beryllium is located throughout the workplace, they cannot identify the direction of the pathways between air, surface, or skin. Ranking strategies helped to identify jobs with the highest combined air, glove, and/or surface exposures. All previously identified high-risk jobs had high air concentrations, dermal mass loading, or both, and none had low dermal and air. We have found that both pathways are relevant. [Supplementary materials are available for this article. Go to the publisher's online edition of Journal of Occupational and Environmental Hygiene for the following free supplemental resource: a file describing the forms of beryllium materials encountered during production and characteristics of the aerosols by process areas.].

Water-based solutions are the best decontaminating fluids for dermal corrosive exposures: a mini review.

PubMed

Brent, Jeffrey

2013-01-01

The intention is to assess whether the fundamental principle ("the solution to pollution is dilution") should be the guide for the initial medical management of corrosive dermal exposures. The US National Library of Medicine Pubmed database was searched utilizing all combinations of the search terms "decontamination", "corrosive", and "dermal". A separate search was done specifically related to hydrofluoric acid. These searches found 69 relevant papers. Only four controlled clinical studies comparing early and intensive water decontamination with no or less dilution treatment have been published on human corrosive dermal exposures. Although the authors' conclusion in the first study of 273 patients was that those that had more intensive water irrigation tended to have less time to skin grafting and shorter periods of hospitalization, the results were not statistically significant. In the second study of 51 patients, those who had "adequate" decontamination (immediate dilution or neutralization therapy) had shortened length of stay (7.2 vs. 16.2 days), lower mortality (9.5% vs. 21%), and fewer skin grafts (19% vs. 36%) despite having slightly greater burn surface area (19.7% vs. 17.2%). However, no statistical analysis was provided. The third and fourth studies were conducted in the same center. In the third study of 35 patients, those who had "immediate" water lavage (done within 10 min of exposure and continued for at least 15 min) had significantly fewer burns that progressed to full thickness (12.5% vs. 63%; p < 0.01) and significantly shorter mean hospital stays (7.7 days vs. 20.5 days; p < 0.01) than those who did not, despite the mean total burn surface area being twice as large in the adequate water decontamination group (12% vs. 6%; p < 0.05). In the fourth study of 83 patients (35 of whom had been reported in the previous study), those who had copious water lavage within 3 min of injury were less likely to progress to full thickness burns (13.5% vs. 60.8%; p < 0.01), had fewer delayed complications (5.4% vs. 30.4%; p < 0.01) and shorter lengths of stay (6.2 vs. 22 days; p < 0.01), compared with those who did not. In a further study, water was compared to the proprietary agent Diphoterine(®) in a controlled prospective cohort study of 180 dermal alkali exposures. The Diphoterine(®) first group was decontaminated significantly faster than the water first group (median times to irrigation 1 vs. 5 min; p < 0.001). No analysis adjusted for time to decontamination was provided, so the study demonstrated that only those individuals who decontaminated early did better than those who decontaminated later. The data support water as the best decontaminating solution. It has been shown to be efficacious in clinical trials, is widely available, and inexpensive.

Household products: a review.

PubMed

DiCarlo, Marc A

2003-10-01

Household products include detergents, cleaners and polishes, bleaches, disinfectants and sterilizers, dust removers, antistatics and deodorizers, office materials, removers, and products for clothing. Many of these contain chemicals that present a risk to those who come into contact with them. This contact may be through inhalation or dermal exposure for human adults, or by ingestion for children. Pets are exposed through ingestion, dermal contact, and inhalation. An emerging class of household products is the fabric refreshers, which may pose a hazard to humans and pets. This review explores the major chemicals expected in typical fabric refreshers, "and their potential hazards to household pets.

EVALUATING COMMERCIALLY AVAILABLE DERMAL ...

EPA Pesticide Factsheets

As the Human Exposure Program focuses on the exposure of children to pesticides, there are concerns about the effect, or perceived effect, of components of the sampling procedure on the health and well-being of the infant and the ability to collect pesticide residues. One concern involves the materials in wipes used to collect pesticide residues or other contact materials on the skin. In recent studies (e.g., National Human Exposure Assessment Survey; NHEXAS), isopropyl alcohol has been used as a solvent in conjunction with a cloth wipe to obtain samples from the hands of adults and children. Although isopropyl alcohol is generally considered innocuous, the use of commercially available products could eliminate concerns about exposure to alcohol. A few studies have evaluated the potential of commercially available baby wipes to collect personal exposure samples for metals research, but not for the area of pesticide research (Millson et al., 1994; Campbell et al., 1993; Lichtenwalner et al., 1993). Therefore, there is a need to evaluate the potential for using commercially available baby wipes for collecting pesticide samples from skin and other surfaces. Another concern involves establishing a convenient and safe method for assessing overall dermal exposure for children, especially for those in crawling stage. One route that the U .S. Environmental Protection Agency (EPA) would like to investigate is the use of cotton body suits (infant sleepers) as an indicator

Pesticide Uptake Across the Amphibian Dermis Through Soil and Overspray Exposures

EPA Science Inventory

For terrestrial amphibians, accumulation ofpesticides through dermal contact is a primary route ofexposure in agricultural landscapes and may be contributingto widespread amphibian declines. To show pesticidetransfer across the amphibian dermis at permitted labelapplication rates...

Public health assessment for petro-processors of Lousiana Incorporated, Baton Rouge, East Baton Rouge Parish, Louisiana, Region 6. Cerclis No. LAD057482713. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1996-01-16

The Petro-Processors of Louisiana, Inc. (PPI) site, located in East Baton Rouge Parish, Louisiana, operated two waste disposal facilities: the Brooklawn area and the Scenic Highway area. Both areas contain chlorinated aromatic hydrocarbons and chlorinated hydrocarbons. Contaminants have been detected in samples from soil, groundwater, surface water, and air at the Brooklawn area and in soil, groundwater, and air at the Scenic Highway area. The site is considered a public health hazard because of risks to human health from past, present, and future exposure to hazardous substances. Exposure pathways of public health concern are: ingestion of contaminated fish, potential ingestionmore » of contaminated groundwater and wildlife, dermal contact with contaminated sediments, inhalation of airborne volatile contaminants prior to and during remedial activities, and dermal contact and incidental ingestion of contaminated soils.« less

A fugacity-based indoor residential pesticide fate model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bennett, Deborah H.; Furtaw, Edward J.; McKone, Thomas E.

Dermal and non-dietary pathways are potentially significant exposure pathways to pesticides used in residences. Exposure pathways include dermal contact with residues on surfaces, ingestion from hand- and object-to-mouth activities, and absorption of pesticides into food. A limited amount of data has been collected on pesticide concentrations in various residential compartments following an application. But models are needed to interpret this data and make predictions about other pesticides based on chemical properties. In this paper, we propose a mass-balance compartment model based on fugacity principles. We include air (both gas phase and aerosols), carpet, smooth flooring, and walls as model compartments.more » Pesticide concentrations on furniture and toys, and in food, are being added to the model as data becomes available. We determine the compartmental fugacity capacity and mass transfer-rate coefficient for wallboard as an example. We also present the framework and equations needed for a dynamic mass-balance model.« less

Reactive skin decontamination lotion (RSDL) for the decontamination of chemical warfare agent (CWA) dermal exposure.

PubMed

Schwartz, M D; Hurst, C G; Kirk, M A; Reedy, S J D; Braue, E H

2012-08-01

Rapid decontamination of the skin is the single most important action to prevent dermal absorption of chemical contaminants in persons exposed to chemical warfare agents (CWA) and toxic industrial chemicals (TICs) as a result of accidental or intentional release. Chemicals on the skin may be removed by mechanical means through the use of dry sorbents or water. Recent interest in decontamination systems which both partition contaminants away from the skin and actively neutralize the chemical has led to the development of several reactive decontamination solutions. This article will review the recently FDA-approved Reactive Skin Decontamination Lotion (RSDL) and will summarize the toxicity and efficacy studies conducted to date. Evidence of RSDL's superior performance against vesicant and organophosphorus chemical warfare agents compared to water, bleach, and dry sorbents, suggests that RSDL may have a role in mass human exposure chemical decontamination in both the military and civilian arenas.

Risk assessment of dissolved trace metals in drinking water of Karachi, Pakistan.

PubMed

Karim, Zahida

2011-06-01

Health risk caused by the exposure to trace metals in water through different exposure pathways was investigated. Graphite furnace atomic absorption spectrometry was used for the determination of trace metals (nickel, copper, chromium, lead, cobalt, manganese and iron) in drinking water samples. The concentration of metals was compared with the world health organization (WHO) drinking water quality guideline values. Risk of metals on human health was evaluated using Hazard Quotient (HQ). Hazard quotients of all metals through oral ingestion and dermal absorption are found in the range of 1.11 × 10⁻² to 1.35 × 10⁻¹ and 8.52 × 10⁻⁵ to 9.75 × 10⁻², respectively. The results of the present study reflect the unlikely potential for adverse health effects to the inhabitants of Karachi due to the oral ingestion and dermal absorption of water containing these metals.

Texas Bull Nettle (Cnidoscolus texanus) Exposures Reported to Texas Poison Centers.

PubMed

Forrester, Mathias B

2017-06-01

Texas bull nettle (Cnidoscolus texanus) is covered in bristly hairs similar to stinging nettle. Contact with the plant may result in intense dermal pain, burning, itching, cellulitis, and allergic reaction. This study characterizes C texanus exposures reported to a large state-wide poison center system. Cases were C texanus exposures reported to Texas poison centers during 2000-2015. The distribution of cases was determined for patient demographics, exposure circumstances, and patient outcome. A total of 140 C texanus exposures were identified. Twenty percent of the patients were aged ≤5 years, 21% were 6 to 12 years, 5% were 13 to 19 years, and 51% were ≥20years; and 51% of the patients were male. Eighty-one percent of the exposures occurred at the patient's own residence, 11% in a public area, 2% at another residence, and 1% at school. Seventy-eight percent of the patients were managed on site, 13% were already at or en route to a health care facility, and 6% were referred to a health care facility. Eighty-eight percent of the exposures resulted in dermal effects: irritation or pain (56%), erythema or flushing (31%), edema (27%), pruritus (24%), rash (19%), puncture or wound (19%), and hives or welts (11%). C texanus exposures reported to Texas poison centers were most likely to be unintentional and occur at the patient's own residence. The outcomes of the exposures tended not to be serious and could be managed successfully outside of health care facilities. Copyright © 2017 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

Past, present and emerging toxicity issues for jet fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mattie, David R., E-mail: david.mattie@wpafb.af.mil; Sterner, Teresa R.

2011-07-15

The US Air Force wrote the specification for the first official hydrocarbon-based jet fuel, JP-4, in 1951. This paper will briefly review the toxicity of the current fuel, JP-8, as compared to JP-4. JP-8 has been found to have low acute toxicity with the adverse effects being slight dermal irritation and weak dermal sensitization in animals. JP-4 also has low acute toxicity with slight dermal irritation as the adverse effect. Respiratory tract sensory irritation was greater in JP-8 than in JP-4. Recent data suggest exposure to jet fuel may contribute to hearing loss. Subchronic studies for 90 days with JP-8more » and JP-4 showed little toxicity with the primary effect being male rat specific hydrocarbon nephropathy. A 1-year study was conducted for JP-4. The only tumors seen were associated with the male rat specific hydrocarbon nephropathy. A number of immunosuppressive effects have been seen after exposure to JP-8. Limited neurobehavioral effects have been associated with JP-8. JP-8 is not a developmental toxicant and has little reproductive toxicity. JP-4 has not been tested for immune, neurobehavioral or reproductive endpoints. JP-8 and JP-4 were negative in mutagenicity tests but JP-4 showed an increase in unscheduled DNA synthesis. Currently, JP-8 is being used as the standard for comparison of future fuels, including alternative fuels. Emerging issues of concern with jet fuels include naphthalene content, immunotoxicity and inhalation exposure characterization and modeling of complex mixtures such as jet fuels.« less

Past, present and emerging toxicity issues for jet fuel.

PubMed

Mattie, David R; Sterner, Teresa R

2011-07-15

The US Air Force wrote the specification for the first official hydrocarbon-based jet fuel, JP-4, in 1951. This paper will briefly review the toxicity of the current fuel, JP-8, as compared to JP-4. JP-8 has been found to have low acute toxicity with the adverse effects being slight dermal irritation and weak dermal sensitization in animals. JP-4 also has low acute toxicity with slight dermal irritation as the adverse effect. Respiratory tract sensory irritation was greater in JP-8 than in JP-4. Recent data suggest exposure to jet fuel may contribute to hearing loss. Subchronic studies for 90 days with JP-8 and JP-4 showed little toxicity with the primary effect being male rat specific hydrocarbon nephropathy. A 1-year study was conducted for JP-4. The only tumors seen were associated with the male rat specific hydrocarbon nephropathy. A number of immunosuppressive effects have been seen after exposure to JP-8. Limited neurobehavioral effects have been associated with JP-8. JP-8 is not a developmental toxicant and has little reproductive toxicity. JP-4 has not been tested for immune, neurobehavioral or reproductive endpoints. JP-8 and JP-4 were negative in mutagenicity tests but JP-4 showed an increase in unscheduled DNA synthesis. Currently, JP-8 is being used as the standard for comparison of future fuels, including alternative fuels. Emerging issues of concern with jet fuels include naphthalene content, immunotoxicity and inhalation exposure characterization and modeling of complex mixtures such as jet fuels. Copyright © 2011 Elsevier Inc. All rights reserved.

Farmers’ Exposure to Pesticides: Toxicity Types and Ways of Prevention

PubMed Central

Damalas, Christos A.; Koutroubas, Spyridon D.

2016-01-01

Synthetic pesticides are extensively used in agriculture to control harmful pests and prevent crop yield losses or product damage. Because of high biological activity and, in certain cases, long persistence in the environment, pesticides may cause undesirable effects to human health and to the environment. Farmers are routinely exposed to high levels of pesticides, usually much greater than those of consumers. Farmers’ exposure mainly occurs during the preparation and application of the pesticide spray solutions and during the cleaning-up of spraying equipment. Farmers who mix, load, and spray pesticides can be exposed to these chemicals due to spills and splashes, direct spray contact as a result of faulty or missing protective equipment, or even drift. However, farmers can be also exposed to pesticides even when performing activities not directly related to pesticide use. Farmers who perform manual labor in areas treated with pesticides can face major exposure from direct spray, drift from neighboring fields, or by contact with pesticide residues on the crop or soil. This kind of exposure is often underestimated. The dermal and inhalation routes of entry are typically the most common routes of farmers’ exposure to pesticides. Dermal exposure during usual pesticide handling takes place in body areas that remain uncovered by protective clothing, such as the face and the hands. Farmers’ exposure to pesticides can be reduced through less use of pesticides and through the correct use of the appropriate type of personal protective equipment in all stages of pesticide handling. PMID:29051407

Farmers' Exposure to Pesticides: Toxicity Types and Ways of Prevention.

PubMed

Damalas, Christos A; Koutroubas, Spyridon D

2016-01-08

Synthetic pesticides are extensively used in agriculture to control harmful pests and prevent crop yield losses or product damage. Because of high biological activity and, in certain cases, long persistence in the environment, pesticides may cause undesirable effects to human health and to the environment. Farmers are routinely exposed to high levels of pesticides, usually much greater than those of consumers. Farmers' exposure mainly occurs during the preparation and application of the pesticide spray solutions and during the cleaning-up of spraying equipment. Farmers who mix, load, and spray pesticides can be exposed to these chemicals due to spills and splashes, direct spray contact as a result of faulty or missing protective equipment, or even drift. However, farmers can be also exposed to pesticides even when performing activities not directly related to pesticide use. Farmers who perform manual labor in areas treated with pesticides can face major exposure from direct spray, drift from neighboring fields, or by contact with pesticide residues on the crop or soil. This kind of exposure is often underestimated. The dermal and inhalation routes of entry are typically the most common routes of farmers' exposure to pesticides. Dermal exposure during usual pesticide handling takes place in body areas that remain uncovered by protective clothing, such as the face and the hands. Farmers' exposure to pesticides can be reduced through less use of pesticides and through the correct use of the appropriate type of personal protective equipment in all stages of pesticide handling.

Evaluation of inhaled and cutaneous doses of imidacloprid during stapling ornamental plants in tunnels or greenhouses.

PubMed

Aprea, Cristina; Lunghini, Liana; Banchi, Bruno; Peruzzi, Antonio; Centi, Letizia; Coppi, Luana; Bogi, Mirella; Marianelli, Enrico; Fantacci, Mariella; Catalano, Pietro; Benvenuti, Alessandra; Miligi, Lucia; Sciarra, Gianfranco

2009-09-01

The aim of this research was to assess dermal and respiratory exposure of workers to imidacloprid during manual operations with ornamental plants previously treated in greenhouses or tunnels. A total of 10 female workers, 5 in greenhouses and 5 in tunnels, were monitored for 3 or 5 consecutive days. Actual skin contamination, excluding hands, was evaluated using nine filter paper pads placed directly on the skin. To evaluate the efficacy of protective clothing in reducing occupational exposure we also placed four pads on top of the outer clothing. Hand contamination was evaluated by washing with 95% ethanol. Respiratory exposure was evaluated by personal air sampling. Respiratory dose was calculated on the basis of a lung ventilation of 15 l/min. Absorbed doses were calculated assuming a skin penetration of 10% and a respiratory retention of 100%. Dislodgeable foliar residues (DFRs) were determined during the days of re-entry in order to determine the dermal transfer factor. From the dependence of dermal exposure of hands from DFRs, a mean transfer factor was estimated to be 36.4 cm(2)/h. Imidacloprid was determined by liquid chromatography with selective mass detection and electrospray interface in all matrices analysed. Respiratory dose was 4.1+/-4.0 (0.1-14.3)% and 3.0+/-2.0 (0.6-6.9)% (mean+/-SD (range)) of the total real dose during work in tunnels and greenhouses, respectively. The estimated absorbed doses, 0.29+/-0.45 microg/kg (0.06-2.25 microg/kg) body weight and 0.32+/-0.18 microg/kg (0.07-0.66 microg/kg) body weight (mean+/-SD (range)) in tunnels and in greenhouses, respectively, were less than the acceptable operator exposure level of 0.15 mg/kg body weight and than the acceptable daily intake of 0.05 mg/kg body weight. The hands and exposed skin of all workers were found to be contaminated, indicating that greater precautions, such as daily changing of gloves and clothing, are necessary to reduce skin exposure.

Assessment of exposure to pesticides during mixing/loading and spraying of tomatoes in the open field.

PubMed

Aprea, Maria Cristina; Bosi, Anna; Manara, Michele; Mazzocchi, Barbara; Pompini, Alessandra; Sormani, Francesca; Lunghini, Liana; Sciarra, Gianfranco

2016-01-01

Some evidence of exposure-response of metolachlor and pendimethalin for lung cancer and an association of metribuzin with risk of glioma have been reported. The primary objectives in this study were to evaluate exposure and occupational risk during mixing/loading of pesticides and during their application to tomatoes cultivated in open fields. Sixteen farmers were sampled. Respiratory exposure was estimated by personal air sampling using fiberglass filters in a IOM device. Dermal exposure was assessed using skin pads and hand washing. Absorbed doses were estimated assuming 100% lung retention, and 50% or 10% skin absorption for metribuzin, and pendimethalin and metolachlor, respectively. The three pesticides were quantified by gas chromatography tandem mass spectrometry in all matrices. Metolachlor was used as a tracer of contamination of clothes and tractors unrelated to the exposure monitored. Respiratory exposure to metribuzin, used in granular form, was on average more than one order of magnitude higher than exposure to pendimethalin, used in the form of microencapsulated liquid. The actual doses were 0.067-8.08 µg/kg bw, 0.420-12.6 µg/kg bw, and 0.003-0.877 µg/kg bw for pendimethalin, metribuzin, and metolachlor, respectively. Dermal exposure was about 88% of the actual dose for metribuzin and more than 95%, for pendimethalin and metolachlor. For risk assessment, the total absorbed doses (sum of respiratory and skin absorbed doses) were compared with the AOEL for each compound. The actual and absorbed doses of the three pesticides were always lower than the acceptable operator exposure level (AOEL), which are reported to be 234 µg/kg bw, 20 µg/kg bw, and 150 µg/kg bw for pendimethalin, metribuzin, and metolachlor, respectively. In any case, personal protective equipment and spraying devices should be chosen with care to minimize exposure.

Protective effect of crocin on ultraviolet B‑induced dermal fibroblast photoaging.

PubMed

Deng, Mingwu; Li, Dong; Zhang, Yichen; Zhou, Guangdong; Liu, Wei; Cao, Yilin; Zhang, Wenjie

2018-06-11

Ultraviolet B (UVB) radiation induces the production of reactive oxygen species (ROS), resulting in the aging of dermal fibroblasts. Crocin, a bioactive constituent of Crocus sativus, possesses anti‑oxidation effects. The purpose of the present study was to evaluate the protective effect of crocin on UVB‑induced dermal fibroblast photoaging. Human dermal fibroblasts were isolated and cultured with different concentrations of crocin prior to and following exposure to UVB irradiation. The senescent phenotypes of cells were evaluated, including cell proliferation, cell cycle, senescence‑associated β‑galactosidase (SA‑β‑gal) expression, intracellular ROS, expression of antioxidant protein glutathione peroxidase 1 (GPX‑1) and extracellular matrix protein collagen type 1 (Col‑1). Crocin rescued the cell proliferation inhibited by UVB irradiation, prevented cell cycle arrest and markedly decreased the number of SA‑β‑gal‑positive cells. In addition, crocin reduced UVB‑induced ROS by increasing GPX‑1 expression and other direct neutralization effects. Furthermore, crocin promoted the expression of the extracellular matrix protein Col‑1. Crocin could effectively prevent UVB‑induced cell damage via the reduction of intracellular ROS; thus, it could potentially be used in the prevention of skin photoaging.

Concentrations of synthetic musk compounds in personal care and sanitation products and human exposure profiles through dermal application.

PubMed

Roosens, Laurence; Covaci, Adrian; Neels, Hugo

2007-11-01

Synthetic musks, such as 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene (AHTN) and 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-gamma-2-benzopyran (HHCB), musk ketone (MK) and musk xylene (MX), are used as an alternative for natural musk. Due to their widespread use, these synthetic compounds turned up in different environmental compartments, such as wastewater, human and animal tissues. Yet, little is known about their distribution and occurrence in personal care and household products, information needed in order to evaluate the different human exposure routes. This paper gives an overview of the synthetic musk levels in six different product categories: body lotions, perfumes, deodorants, hair care products, shower products and sanitation products. Especially body lotions, perfumes and deodorants contained high levels of synthetic musks. Maximum concentrations of HHCB, AHTN, MX and MK were 22 mg g(-1), 8 mg g(-1), 26 microg g(-1) and 0.5 microg g(-1), respectively. By combining these results with the average usage of consumer products, low-, medium- and high-exposure profiles through dermal application could be estimated. HHCB was the highest contributor to the total amount of synthetic musks in every exposure profile (18-23 700 microg d(-1)). Exposure to MK and MX did not increase substantially (10-20-fold) between low- and high-exposure profiles, indicating that these compounds cover a less broad range. In comparison, exposure to HHCB and AHTN increased up to 10 000 fold between low- and high-exposure.

FUGACITY-BASED INDOOR RESIDENTIAL PESTICIDE FATE MODEL

EPA Science Inventory

Dermal and non-dietary pathways are possibly important for exposure to pesticides used in residences. Limited data have been collected on pesticide concentrations in residential air and surfaces following application. Models may be useful for interpreting these data and to make...

CHARACTERIZING RESIDUE TRANSFER EFFICIENCIES USING A FLUORESCENT IMAGING TECHNIQUE

EPA Science Inventory

To reduce the uncertainty associated with current estimates of children's exposure to pesticides by dermal contact and indirect ingestion, residue transfer data are required. Prior to conducting exhaustive studies, a screening study to identify the important parameters for chara...

Variability in the skin exposure of machine operators exposed to cutting fluids.

PubMed

Wassenius, O; Järvholm, B; Engström, T; Lillienberg, L; Meding, B

1998-04-01

This study describes a new technique for measuring skin exposure to cutting fluids and evaluates the variability of skin exposure among machine operators performing cyclic (repetitive) work. The technique is based on video recording and subsequent analysis of the video tape by means of computer-synchronized video equipment. The time intervals at which the machine operator's hand was exposed to fluid were registered, and the total wet time of the skin was calculated by assuming different evaporation times for the fluid. The exposure of 12 operators with different work methods was analyzed in 6 different workshops, which included a range of machine types, from highly automated metal cutting machines (ie, actual cutting and chip removal machines) requiring operator supervision to conventional metal cutting machines, where the operator was required to maneuver the machine and manually exchange products. The relative wet time varied between 0% and 100%. A significant association between short cycle time and high relative wet time was noted. However, there was no relationship between the degree of automatization of the metal cutting machines and wet time. The study shows that skin exposure to cutting fluids can vary considerably between machine operators involved in manufacturing processes using different types of metal cutting machines. The machine type was not associated with dermal wetness. The technique appears to give objective information about dermal wetness.

Risk-Based High-Throughput Chemical Screening and Prioritization using Exposure Models and in Vitro Bioactivity Assays.

PubMed

Shin, Hyeong-Moo; Ernstoff, Alexi; Arnot, Jon A; Wetmore, Barbara A; Csiszar, Susan A; Fantke, Peter; Zhang, Xianming; McKone, Thomas E; Jolliet, Olivier; Bennett, Deborah H

2015-06-02

We present a risk-based high-throughput screening (HTS) method to identify chemicals for potential health concerns or for which additional information is needed. The method is applied to 180 organic chemicals as a case study. We first obtain information on how the chemical is used and identify relevant use scenarios (e.g., dermal application, indoor emissions). For each chemical and use scenario, exposure models are then used to calculate a chemical intake fraction, or a product intake fraction, accounting for chemical properties and the exposed population. We then combine these intake fractions with use scenario-specific estimates of chemical quantity to calculate daily intake rates (iR; mg/kg/day). These intake rates are compared to oral equivalent doses (OED; mg/kg/day), calculated from a suite of ToxCast in vitro bioactivity assays using in vitro-to-in vivo extrapolation and reverse dosimetry. Bioactivity quotients (BQs) are calculated as iR/OED to obtain estimates of potential impact associated with each relevant use scenario. Of the 180 chemicals considered, 38 had maximum iRs exceeding minimum OEDs (i.e., BQs > 1). For most of these compounds, exposures are associated with direct intake, food/oral contact, or dermal exposure. The method provides high-throughput estimates of exposure and important input for decision makers to identify chemicals of concern for further evaluation with additional information or more refined models.

A Probabilistic Risk Assessment for Deployed Military Personnel After the Implementation of the Leishmaniasis Control Program at Tallil Air Base, Iraq

DTIC Science & Technology

2009-01-01

used ADE FE (SAfemale/ SAmale ), [4] where ADE is the adjusted dermal exposure (mg/lb [AI]), FE is the ßagger exposure, SAfemale is the sur- face...area of an adult woman as estimated by equation 3, and SAmale is the surface area of an adult man as estimated by equation 3. We assumed a triangular

The long term immunological response of swine after two exposures to a salmon thrombin and fibrinogen hemostatic bandage

PubMed Central

Rothwell, Stephen W.; Settle, Timothy; Wallace, Shannon; Dorsey, Jennifer; Simpson, David; Bowman, James R.; Janmey, Paul; Sawyer, Evelyn

2014-01-01

Experimental salmon thrombin/fibrinogen dressings have been shown to provide effective hemostasis in severe hemorrhage situations. The hypothesis for this study was that swine would still remain healthy without coagulopathy six months after exposure to salmon thrombin/fibrinogen dressings. Initial exposure was by insertion of the salmon dressing into the peritoneal cavity. Three months after the initial exposure, the same animals were subjected to two full thickness dermal wounds on the dorsal surface. One wound was bandaged with the salmon thrombin/fibrinogen bandage and the other wound was dressed with a standard bandage. The animals were monitored for an additional three months. Blood was drawn every 14 days over the six months for immunological and coagulation function analysis. All of the animals (8 pigs) remained healthy during the six month period and the dermal wounds healed without incidence. Lymph nodes and spleen showed signs of normal immune response and Western blots showed development of antibodies against salmon fibrinogen, but none of the animals made antibodies that recognized any species of thrombin. Coagulation parameters (fibrinogen concentration, thrombin time, PT and aPTT) and hematological parameters remained normal over the course of the study when compared to initial values of the subject swine. PMID:20705479

Dermal Exposure to Cumene Hydroperoxide: Assessing its Toxic Relevance and Oxidant Potential

PubMed Central

Rider, Cynthia V.; Chan, Po; Herbert, Ron A.; Kissling, Grace E.; Fomby, Laurene M.; Hejtmancik, Milton R.; Witt, Kristine; Waidyanatha, Suramya; Travlos, Greg; Kadiiska, Maria B.

2016-01-01

Cumene hydroperoxide (CHP) is a high production volume chemical that is used to generate phenol and acetone. Dermal exposure to CHP was hypothesized to result in systemic tissue toxicity, production of free radicals and consequent decrease of plasma antioxidant levels. To evaluate the hypothesis and characterize the toxicity of CHP, male and female B6C3F1/N mice and F344/N rats were exposed to varying doses of CHP applied topically for 14 or 90 days. No significant changes in survival or body weight of mice and rats were observed following 14 days of exposure. However, 90 days of CHP exposure at the high dose (12 mg/kg) triggered a significant decrease (−15%) in the body weight of the male rat group only. Irritation of the skin was observed at the site of application and was characterized by inflammation and epidermal hyperplasia. In treated animals, histology of liver tissue, free radical generation, and antioxidant levels in blood plasma were not significantly changed as compared to the corresponding controls. Consistent with the lack of systemic damage, no increase in micronucleated erythrocytes was seen in peripheral blood. In conclusion, topical CHP application caused skin damage only at the application site and did not cause systemic tissue impairment. PMID:26985019

Nitroxides are more efficient inhibitors of oxidative damage to calf skin collagen than antioxidant vitamins.

PubMed

Venditti, Elisabetta; Scirè, Andrea; Tanfani, Fabio; Greci, Lucedio; Damiani, Elisabetta

2008-01-01

Reactive oxygen species generated upon UV-A exposure appear to play a major role in dermal connective tissue transformations including degradation of skin collagen. Here we investigate on oxidative damage to collagen achieved by exposure to (i) UV-A irradiation and to (ii) AAPH-derived radicals and on its possible prevention using synthetic and natural antioxidants. Oxidative damage was identified through SDS-PAGE, circular dichroism spectroscopy and quantification of protein carbonyl residues. Collagen (2 mg/ml) exposed to UV-A and to AAPH-derived radicals was degraded in a time- and dose-dependent manner. Upon UV-A exposure, maximum damage was observable at 730 kJ/m2 UV-A, found to be equivalent to roughly 2 h of sunshine, while exposure to 5 mM AAPH for 2 h at 50 degrees C lead to maximum collagen degradation. In both cases, dose-dependent protection was achieved by incubation with muM concentrations of nitroxide radicals, where the extent of protection was shown to be dictated by their structural differences whereas the vitamins E and C proved less efficient inhibitors of collagen damage. These results suggest that nitroxide radicals may be able to prevent oxidative injury to dermal tissues in vivo alternatively to commonly used natural antioxidants.

Investigation of respiratory and dermal symptoms associated with metal working fluids at an aircraft engine manufacturing facility.

PubMed

Meza, Francisco; Chen, Lilia; Hudson, Naomi

2013-12-01

Each year, 1.2 million metalworkers are exposed to metalworking fluids (MWFs), which can cause dermal and respiratory disease. The National Institute for Occupational Safety and Health (NIOSH) conducted a health hazard evaluation of MWF exposures at an aircraft engine manufacturing facility. The objectives were to determine employee exposures to endotoxin and MWFs in the air, characterize symptoms experienced by employees working with MWFs, compare them to symptoms of employees unexposed to MWFs, and make recommendations for reducing exposures based on results. Four hundred seven workers were categorized as MWF exposed or MWF unexposed and completed questionnaires. Estimated prevalence ratios (PR) of dermatitis, asthma, and work-related asthma (WRA) symptoms were calculated. Airborne concentrations of MWF and endotoxin were measured, and work practices observed. MWF exposed workers had a significantly higher prevalence of dermatitis on wrists/forearms (PR 2.59; 95% CI 1.22, 5.46), asthma symptoms (PR 1.49; 95% CI 1.05, 2.13), and WRA symptoms (PR 2.10; 95% CI 1.22, 3.30) than unexposed workers. Airborne concentrations of MWF were below the NIOSH recommended exposure limit (REL) for MWF aerosols (thoracic particulate mass). Despite MWF exposures below the NIOSH REL, exposed workers had a higher prevalence of asthma, WRA, and dermatitis symptoms than unexposed workers. Recommendations to reduce exposure included configuring mist collectors to automatically turn on when the machine is in use, and enforcing enclosure use. © 2013 Wiley Periodicals, Inc.

Investigation of Respiratory and Dermal Symptoms Associated with Metal Working Fluids at an Aircraft Engine Manufacturing Facility

PubMed Central

Meza, Francisco; Chen, Lilia; Hudson, Naomi

2015-01-01

Background Each year, 1.2 million metalworkers are exposed to metalworking fluids (MWFs), which can cause dermal and respiratory disease. The National Institute for Occupational Safety and Health (NIOSH) conducted a health hazard evaluation of MWF exposures at an aircraft engine manufacturing facility. The objectives were to determine employee exposures to endotoxin and MWFs in the air, characterize symptoms experienced by employees working with MWFs, compare them to symptoms of employees unexposed to MWFs, and make recommendations for reducing exposures based on results. Methods 407 workers were categorized as MWF exposed or MWF unexposed and completed questionnaires. Estimated prevalence ratios (PR) of dermatitis, asthma, and work-related asthma (WRA) symptoms were calculated. Airborne concentrations of MWF and endotoxin were measured, and work practices observed. Results MWF exposed workers had a significantly higher prevalence of dermatitis on wrists/forearms (PR 2.59; 95% CI 1.22, 5.46), asthma symptoms (PR 1.49; 95% CI 1.05, 2.13) and WRA symptoms (PR 2.10; 95% CI 1.22, 3.30) than unexposed workers. Airborne concentrations of MWF were below the NIOSH recommended exposure limit (REL) for MWF aerosols (thoracic particulate mass). Conclusions Despite MWF exposures below the NIOSH REL, exposed workers had a higher prevalence of asthma, WRA, and dermatitis symptoms than unexposed workers. Recommendations to reduce exposure included configuring mist collectors to automatically turn on when the machine is in use, and enforcing enclosure use. PMID:24122918

The Health Risk of Cd Released from Low-Cost Jewelry.

PubMed

Pouzar, Miloslav; Zvolská, Magdalena; Jarolím, Oldřich; Audrlická Vavrušová, Lenka

2017-05-12

The composition of the surface layer of 13 low-cost jewelry samples with a high Cd content was analyzed using an energy-dispersive X-ray fluorescence spectrometer (ED XRF). The analyzed jewels were obtained in cooperation with the Czech Environmental Inspectorate. The jewels were leached in two types of artificial sweat (acidic and alkaline) for 7 days. Twenty microliters of the resulting solution was subsequently placed on a paper carrier and analyzed by an LIBS (Laser-Induced Breakdown Spectrometry) spectrometer after drying. The Cd content in the jewelry surface layer detected by using ED XRF ranged from 13.4% to 44.6% (weight per weight-w/w). The samples were subsequently leached in artificial alkaline, and the acidic sweat and leachates were analyzed using laser-induced breakdown spectrometry (LIBS). The amount of released Cd into alkaline sweat ranged from 24.0 to 370 µg Cd per week, respectively 3.23-61.7 µg/cm²/week. The amount of released Cd into acidic sweat ranged from 16.4 to 1517 µg Cd per week, respectively 3.53-253 µg/cm²/week. The limit of Cd for dermal exposure is not unequivocally determined in the countries of the EU (European Union) or in the U.S. Based on the US EPA (United States Environmental Protection Agency) approach used to establish the reference dose (RfD) for Cd contained in food and information about the bioavailability of Cd after dermal exposure, we assessed our own value of dermal RfD. The value was compared with the theoretical amount of Cd, which can be absorbed into the organism from jewelry in contact with the skin. The calculation was based on the amount of Cd that was released into acidic and alkaline sweat. The highest amount of Cd was released into acidic sweat, which represents 0.1% of dermal RfD and into alkaline sweat, 0.5% of dermal RfD. These results indicate that the analyzed jewelry contains Cd over the limit for composition of jewelry available within the territory of the EU. The determined amount of Cd in analyzed jewelry does not, however, pose a threat in terms of carcinogenic toxic effects.

In vitro percutaneous absorption and metabolism of Bisphenol A (BPA) through fresh human skin.

PubMed

Toner, Frank; Allan, Graham; Dimond, Stephen S; Waechter, John M; Beyer, Dieter

2018-03-01

Bisphenol A (BPA) is a high production volume compound. It is mainly used as a monomer to make polymers for various applications including food-contact materials. The primary route of exposure to BPA in the general population is through oral intake (EFSA 2015) however, other potential sources of exposure have also been identified, such as dermal contact. In the present study, the percutaneous absorption through human skin has been investigated in an in vitro study according to OECD TG 428 (Skin Absorption: In Vitro Method). In order to investigate potential dermal BPA metabolism during absorption, radiolabelled BPA was applied to fresh, metabolically competent, human skin samples (ring labelled 14 C BPA concentrations tested were 2.4, 12, 60 and 300mg/L). Measured as total radioactivity the mean absorbed dose (receptor compartment) ranged from 1.7-3.6% of the applied doses and the dermal delivery (epidermis+dermis+receptor compartment), sometimes also named bioavailable dose was 16-20% of the applied doses, with the majority of the radioactivity associated with epidermis compared to dermis and receptor fluid. No metabolism was observed in any of the epidermis samples; however some metabolism was observed in dermis and receptor fluid samples with formation of BPA-glucuronide and BPA-sulfate, and some polar metabolites. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Dermal Uptake of Benzophenone-3 from Clothing.

PubMed

Morrison, Glenn C; Bekö, Gabriel; Weschler, Charles J; Schripp, Tobias; Salthammer, Tunga; Hill, Jonathan; Andersson, Anna-Maria; Toftum, Jørn; Clausen, Geo; Frederiksen, Hanne

2017-10-03

Benzophenone-3 (also known as BP-3 or oxybenzone) is added to sunscreens, plastics, and some coatings to filter UV radiation. The suspected endocrine disruptor BP-3 has been detected in the air and settled dust of homes and is expected to redistribute from its original sources to other indoor compartments, including clothing. Given its physical and chemical properties, we hypothesized that dermal uptake from clothing could contribute to the body burden of this compound. First, cotton shirts were exposed to air at an elevated concentration of BP-3 for 32 days; the final air concentration was 4.4 μg/m 3 . Next, three participants wore the exposed shirts for 3 h. After 3 h of exposure, participants wore their usual clothing during the collection of urine samples for the next 48 h. Urine was analyzed for BP-3, a metabolite (BP-1), and six other UV filters. The rate of urinary excretion of the sum of BP-1 and BP-3 increased for all participants during and following the 3 h of exposure. The summed mass of BP-1 and BP-3 excreted during the first 24 h attributable to wearing exposed t-shirts were 12, 9.9, and 82 μg for participants 1, 2, and 3, respectively. Analysis of these results, coupled with predictions of steady-state models, suggest that dermal uptake of BP-3 from clothing could meaningfully contribute to overall body burden.

Estimating Dermal Transfer of Copper Particles from the ...

EPA Pesticide Factsheets

Lumber pressure-treated with micronized copper was examined for the release of copper and copper micro/nanoparticles using a surface wipe method to simulate dermal transfer. In 2003, the wood industry began replacing CCA treated lumber products for residential use with copper based formulations. Micronized copper (nano to micron sized particles) has become the preferred treatment formulation. There is a lack of information on the release of copper, the fate of the particles during dermal contact, and the copper exposure level to children from hand-to-mouth transfer. For the current study, three treated lumber products, two micronized copper and one ionic copper, were purchased from commercial retailers. The boards were left to weather outdoors for approximately 1 year. Over the year time period, hand wipe samples were collected periodically to determine copper transfer from the wood surfaces. The two micronized formulations and the ionic formulation released similar levels of total copper. The amount of copper released was high initially, but decreased to a constant level (~1.5 mg m-2) after the first month of outdoor exposure. Copper particles were identified on the sampling cloths during the first two months of the experiment, after which the levels of copper were insufficient to collect interpretable data. After 1 month, the particles exhibited minimal changes in shape and size. At the end of 2-months, significant deterioration of the particles was

Quantifying Amphibian Pesticide Body Burdens for Active Ingredients Versus Formulations Through Dermal Exposure

EPA Science Inventory

Widespread pesticide applications throughout agricultural landscapes pose a risk to post-metamorphic amphibians leaving or moving between breeding ponds in terrestrial habitats. Recent studies indicate that the inactive ingredients in pesticide formulations may be equally or more...

STUDY TO IDENTIFY IMPORTANT PARAMETERS FOR CHARACTERIZING PESTICIDE RESIDUE TRANSFER EFFICIENCIES

EPA Science Inventory

To reduce the uncertainty associated with current estimates of children's exposure to pesticides by dermal contact and non-dietary ingestion, residue transfer data are required. Prior to conducting exhaustive studies, a screening study to identify the important parameters for...

CHARACTERIZING PESTICIDE RESIDUE TRANSFER EFFICIENCIES USING FLUORESCENT TRACER IMAGING TECHNIQUES

EPA Science Inventory

To reduce the uncertainty associated with current estimates of children's exposure to pesticides by dermal contact and non-dietary ingestion, residue transfer data are required. Prior to conducting exhaustive studies, a screening study was conducted to identify the important pa...

Complete horizontal skin cell resurfacing and delayed vertical cell infiltration into porcine reconstructive tissue matrix compared to bovine collagen matrix and human dermis.

PubMed

Mirastschijski, Ursula; Kerzel, Corinna; Schnabel, Reinhild; Strauss, Sarah; Breuing, Karl-Heinz

2013-10-01

Xenogenous dermal matrices are used for hernia repair and breast reconstruction. Full-thickness skin replacement is needed after burn or degloving injuries with exposure of tendons or bones. The authors used a human skin organ culture model to study whether porcine reconstructive tissue matrix (Strattice) is effective as a dermal tissue replacement. Skin cells or split-thickness skin grafts were seeded onto human deepidermized dermis, Strattice, and Matriderm. Cellular resurfacing and matrix infiltration were monitored by live fluorescence imaging, histology, and electron microscopy. Proliferation, apoptosis, cell differentiation, and adhesion were analyzed by immunohistochemistry. Epithelial resurfacing and vertical proliferation were reduced and delayed with both bioartificial matrices compared with deepidermized dermis; however, no differences in apoptosis, cell differentiation, or basement membrane formation were found. Vertical penetration was greatest on Matriderm, whereas no matrix infiltration was found on Strattice in the first 12 days. Uncompromised horizontal resurfacing was greatest with Strattice but was absent with Matriderm. Strattice showed no stimulatory effect on cellular inflammation. Matrix texture and surface properties governed cellular performance on tissues. Although dense dermal compaction delayed vertical cellular ingrowth for Strattice, it allowed uncompromised horizontal resurfacing. Dense dermal compaction may slow matrix decomposition and result in prolonged biomechanical stability of the graft. Reconstructive surgeons should choose the adequate matrix substitute depending on biomechanical requirements at the recipient site. Strattice may be suitable as a dermal replacement at recipient sites with high mechanical load requirements.

Estimating dermal transfer from PCB-contaminated porous surfaces.

PubMed

Slayton, T M; Valberg, P A; Wait, A D

1998-06-01

Health risks posed by dermal contact with PCB-contaminated porous surfaces have not been directly demonstrated and are difficult to estimate indirectly. Surface contamination by organic compounds is commonly assessed by collecting wipe samples with hexane as the solvent. However, for porous surfaces, hexane wipe characterization is of limited direct use when estimating potential human exposure. Particularly for porous surfaces, the relationship between the amount of organic material collected by hexane and the amount actually picked up by, for example, a person's hand touch is unknown. To better mimic PCB pickup by casual hand contact with contaminated concrete surfaces, we used alternate solvents and wipe application methods that more closely mimic casual dermal contact. Our sampling results were compared to PCB pickup using hexane-wetted wipes and the standard rubbing protocol. Dry and oil-wetted samples, applied without rubbing, picked up less than 1% of the PCBs picked up by the standard hexane procedure; with rubbing, they picked up about 2%. Without rubbing, saline-wetted wipes picked up 2.5%; with rubbing, they picked up about 12%. While the nature of dermal contact with a contaminated surface cannot be perfectly reproduced with a wipe sample, our results with alternate wiping solvents and rubbing methods more closely mimic hand contact than the standard hexane wipe protocol. The relative pickup estimates presented in this paper can be used in conjunction with site-specific PCB hexane wipe results to estimate dermal pickup rates at sites with PCB-contaminated concrete.

Dermal uptake and excretion of 4,4'-methylenedianiline during rotor blade production in helicopter industry--an intervention study.

PubMed

Weiss, Tobias; Schuster, Hubert; Müller, Johannes; Schaller, Karl-Heinz; Drexler, Hans; Angerer, Jürgen; Käfferlein, Heiko U

2011-10-01

Workers using composite materials by fibre reinforced laminate technology are exposed to 4,4'-methylenedianiline (MDA), a liver toxicant and suspected human carcinogen, during the production of rotor blades in helicopter industry. The aim of the study presented here was to assess the internal dose of MDA and the suitability of various personal protection measures at the workplace. Ambient monitoring and biological monitoring was carried out by analysing MDA in air and urine samples in seven workers of a highly specialized workplace (rotor blade production). Three different concepts of personal protection measures were applied to study the route of uptake and to evaluate strategies in decreasing workplace exposure. In addition, elimination kinetics of MDA was studied in three workers who were exposed to MDA on three consecutive working days. Ambient monitoring consistently provided air levels at or below the limit of quantification of 0.1 μg m(-3). Nevertheless, MDA was detected in 89% of all post-shift urine samples and median concentration was 4.2 μg l(-1). MDA in urine were >20 times higher than expected on data from ambient monitoring alone. A significant decrease in exposure could be achieved when workers have worn MDA-protective overalls in combination with MDA-protective gloves and a splash protection shield (from 9.8 μg l(-1) down to 3.7 μg l(-1)). The results show that MDA is taken up primarily via the skin at the workplaces under study. The excretion of MDA in urine was observed to be delayed after dermal exposure. Exposure assessment of MDA should be carried out by biological monitoring rather than ambient monitoring. For this purpose, urine samples midweek or at the end of the week should be used based on the observed delay in the excretion of MDA after dermal absorption. Uptake of MDA via the skin could not be completely avoided even if state-of-the-art personal protection measures were applied.

Exposure to sub-10nm particles emitted from a biodiesel-fueled diesel engine: In vitro toxicity and inflammatory potential.

PubMed

Malorni, Livia; Guida, Vincenzo; Sirignano, Mariano; Genovese, Giuliana; Petrarca, Claudia; Pedata, Paola

2017-03-15

The inflammatory effects of organic sub-10nm particles generated and emitted from a diesel engine fueled with a biodiesel and a commercial diesel oil are analyzed in this paper. Diesel combustion is the major sources of ultrafine particles (UFP) in the environment, particularly in urbanized areas. In the last years, there is an increasing use of biomass-derived fuels because they are a renewable source of energy that may mitigate climate change through the reduction of net CO 2 with respect to conventional fossil fuels. Although there is a general agreement on biofuels ability to reduce conventional pollutants, new and potentially harmful pollutants can be formed during biofuel combustion. In particular, the emission of sub-10nm particles is strongly increased with respect to that of larger soot particles. Organic sub-10nm particles are separated from larger sizes particulate matter by collection in water suspension for toxicological and inflammatory tests. After exposure to sub-10nm particles, the effects on proliferation, apoptosis and secretion of cytokines, chemokines and growth factors networks production is analyzed in immortalized non-tumorigenic human dermal keratinocyte cell line (HaCaT) and human alveolar epithelial-like cells (A549). Nanoparticles exert different cytotoxic effects in the two cell lines, suggesting that the dermal way of exposure is more sensitive than the inhalant way. These differences are most evident in the secretion of pro-inflammatory, angiogenic and proliferative cytokines and chemokines whose expression is more finely modulated in HaCaT cells compared to A-549 cells. Considering the size of these particles, it is important to promote the culture of prevention also for the dermal way in particularly exposed workers. Copyright © 2017 Elsevier B.V. All rights reserved.

Increased susceptibility of skin from HERDA (Hereditary Equine Regional Dermal Asthenia)-affected horses to bacterial collagenase degradation: a potential contributing factor to the clinical signs of HERDA.

PubMed

Rashmir-Raven, Ann; Lavagnino, Michael; Sedlak, Aleksa; Gardner, Keri; Arnoczky, Steven

2015-12-01

Hereditary equine regional dermal asthenia (HERDA) is a genetic disorder of collagen resulting in fragile, hyper-extensible skin and ulcerative lesions. The predominance of skin lesions have been shown to occur on the dorsum of HERDA-affected horses. While this has been postulated to be due to increased exposure to sunlight of these areas, the precise pathological mechanism which causes this to occur is unclear. We hypothesized that an increase in collagenase activity, that has been associated with the exposure of dermal fibroblasts to sunlight, will significantly degrade the material properties of skin from HERDA-affected horses when compared to unaffected controls. Six unaffected and seven HERDA-affected horses, all euthanized for other reasons. Full-thickness skin samples from similar locations on each horse were collected and cut into uniform strips and their material properties (tensile modulus) determined by mechanical testing before (n = 12 samples/horse) or after (n = 12 samples/horse) incubation in bacterial collagenase at 37°C for 6 h. The change in modulus following treatment was then compared between HERDA-affected and unaffected horses using a Student's t-test. The modulus of skin from HERDA-affected horses decreased significantly more than that from unaffected horses following collagenase treatment (54 ± 7% versus 30 ± 16%, P = 0.004). The significant decrease in the modulus of skin from HERDA-affected horses following collagenase exposure suggests that their altered collagen microarchitecture is more susceptible to enzymatic degradation and may explain the localization of skin lesions in HERDA-affected horses to those areas of the body most exposed to sunlight. These findings appear to support the previously reported benefits of sunlight restriction in HERDA-affected horses. © 2015 ESVD and ACVD.

Dermal uptake of nicotine from air and clothing: Experimental verification.

PubMed

Bekö, G; Morrison, G; Weschler, C J; Koch, H M; Pälmke, C; Salthammer, T; Schripp, T; Eftekhari, A; Toftum, J; Clausen, G

2018-03-01

This study aims to elucidate in greater detail the dermal uptake of nicotine from air or from nicotine-exposed clothes, which was demonstrated recently in a preliminary study. Six non-smoking participants were exposed to gaseous nicotine (between 236 and 304 μg/m 3 ) over 5 hours while breathing clean air through a hood. Four of the participants wore only shorts and 2 wore a set of clean clothes. One week later, 2 of the bare-skinned participants were again exposed in the chamber, but they showered immediately after exposure instead of the following morning. The 2 participants who wore clean clothes on week 1 were now exposed wearing a set of clothes that had been exposed to nicotine. All urine was collected for 84 hours after exposure and analyzed for nicotine and its metabolites, cotinine and 3OH-cotinine. All participants except those wearing fresh clothes excreted substantial amounts of biomarkers, comparable to levels expected from inhalation intake. Uptake for 1 participant wearing exposed clothes exceeded estimated intake via inhalation by >50%. Biomarker excretion continued during the entire urine collection period, indicating that nicotine accumulates in the skin and is released over several days. Absorbed nicotine was significantly lower after showering in 1 subject but not the other. Differences in the normalized uptakes and in the excretion patterns were observed among the participants. The observed cotinine half-lives suggest that non-smokers exposed to airborne nicotine may receive a substantial fraction through the dermal pathway. Washing skin and clothes exposed to nicotine may meaningfully decrease exposure. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

EXPOSURES AND INTERNAL DOSES OF ...

EPA Pesticide Factsheets

The National Center for Environmental Assessment (NCEA) has released a final report that presents and applies a method to estimate distributions of internal concentrations of trihalomethanes (THMs) in humans resulting from a residential drinking water exposure. The report presents simulations of oral, dermal and inhalation exposures and demonstrates the feasibility of linking the US EPA’s information Collection Rule database with other databases on external exposure factors and physiologically based pharmacokinetic modeling to refine population-based estimates of exposure. Review Draft - by 2010, develop scientifically sound data and approaches to assess and manage risks to human health posed by exposure to specific regulated waterborne pathogens and chemicals, including those addressed by the Arsenic, M/DBP and Six-Year Review Rules.

PHYSIOLOGICALLY BASED PHARMACOKINETIC MODEL FOR HUMAN EXPOSURES TO METHYL TERTIARY-BUTYL ETHER

EPA Science Inventory

Humans can be exposed by inhalation, ingestion, or dermal absorption to methyl tertiary-butyl ether (MTBE), an oxygenated fuel additive, from contaminated water sources. The purpose of this research was to develop a physiologically based pharmacokinetic model describing in human...

Dermal Danger? Estimating Pesticide Exposure and Accumulation in Terrestrial Phase Amphibians

EPA Science Inventory

Pesticide registration is required in the US. The EPA must ensure, when used according to label directions: reasonable certainty of no harm to human health, wildlife, fish, and plants, including endangered and non-target species, as well as surface and groundwater.

PROPOSED SUITE OF MODELS FOR ESTIMATING DOSE RESULTING FROM EXPOSURES BY THE DERMAL ROUTE

EPA Science Inventory

Recent risk assessment guidance emphasizes consideration of mechanistic factors for influencing disposition of a toxicant. To incorporate mechanistic information into risk assessment, a suite of models is proposed for use in characterizing and quantifying dosimetry of toxic age...

ANALYSIS OF HOUSEHOLD WATER USE BEHAVIOR FOR USE AS IAQ MODEL PARAMETERS

EPA Science Inventory

Chemicals brought into the home through the domestic water supply, result in human exposure via the three principal routes: ingestion, inhalation, and dermal contact. Disinfection byproducts resulting from the treatment of municipal water supplies lead to the formation of a mix...

The use of bio-monitoring to assess exposure in the electroplating industry

PubMed Central

Beattie, Helen; Keen, Chris; Coldwell, Matthew; Tan, Emma; Morton, Jackie; McAlinden, John; Smith, Paul

2017-01-01

Workers in the electroplating industry are potentially exposed to a range of hazardous substances including nickel and hexavalent chromium (chromium VI) compounds. These can cause serious health effects, including cancer, asthma and dermatitis. This research aimed to investigate whether repeat biological monitoring (BM) over time could drive sustainable improvements in exposure control in the industry. BM was performed on multiple occasions over 3 years, at 53 electroplating companies in Great Britain. Surface and dermal contamination was also measured, and controls were assessed. Air monitoring was undertaken on repeat visits where previous BM results were of concern. There were significant reductions in urinary nickel and chromium levels over the lifetime of this work in the subset of companies where initially, control deficiencies were more significant. Increased risk awareness following provision of direct feedback to individual workers and targeted advice to companies is likely to have contributed to these reductions. This study has shown that exposures to chromium VI and nickel in the electroplating industry occur via a combination of inhalation, dermal and ingestion routes. Surface contamination found in areas such as canteens highlights the potential for transferral from work areas, and the importance of a regular cleaning regime. PMID:26627055

The use of bio-monitoring to assess exposure in the electroplating industry.

PubMed

Beattie, Helen; Keen, Chris; Coldwell, Matthew; Tan, Emma; Morton, Jackie; McAlinden, John; Smith, Paul

2017-01-01

Workers in the electroplating industry are potentially exposed to a range of hazardous substances including nickel and hexavalent chromium (chromium VI) compounds. These can cause serious health effects, including cancer, asthma and dermatitis. This research aimed to investigate whether repeat biological monitoring (BM) over time could drive sustainable improvements in exposure control in the industry. BM was performed on multiple occasions over 3 years, at 53 electroplating companies in Great Britain. Surface and dermal contamination was also measured, and controls were assessed. Air monitoring was undertaken on repeat visits where previous BM results were of concern. There were significant reductions in urinary nickel and chromium levels over the lifetime of this work in the subset of companies where initially, control deficiencies were more significant. Increased risk awareness following provision of direct feedback to individual workers and targeted advice to companies is likely to have contributed to these reductions. This study has shown that exposures to chromium VI and nickel in the electroplating industry occur via a combination of inhalation, dermal and ingestion routes. Surface contamination found in areas such as canteens highlights the potential for transferral from work areas, and the importance of a regular cleaning regime.

Assessing Residential Exposure Risk from Spills of Flowback Water from Marcellus Shale Hydraulic Fracturing Activity

PubMed Central

Abualfaraj, Noura; Olson, Mira S.

2018-01-01

Identifying sources of concern and risk from shale gas development, particularly from the hydraulic fracturing process, is an important step in better understanding sources of uncertainty within the industry. In this study, a risk assessment of residential exposure pathways to contaminated drinking water is carried out. In this model, it is assumed that a drinking water source is contaminated by a spill of flowback water; probability distributions of spill size and constituent concentrations are fit to historical datasets and Monte Carlo simulation was used to calculate a distribution of risk values for two scenarios: (1) use of a contaminated reservoir for residential drinking water supply and (2) swimming in a contaminated pond. The swimming scenario did not produce risks of concern from a single exposure of 1 h duration, but 11 such 1-h exposures did produce risks of 10−6 due to radionuclide exposure. The drinking water scenario over a 30-year exposure duration produced cancer risk values exceeding 10−6 for arsenic, benzene, benzo(a)pyrene, heptachlor, heptachlor epoxide, pentachlorophenol, and vinyl chloride. However, this extended exposure duration is probably not realistic for exposure by a spill event. Radionuclides produced risks in the residential drinking water scenario of 10−6 in just 8 h, a much more realistic timeline for continual exposure due to a spill event. In general, for contaminants for which inhalation exposure was applicable, this pathway produced the highest risks with exposure from ingestion posing the next greatest risk to human health followed by dermal absorption (or body emersion for radionuclides). Considering non-carcinogenic effects, only barium and thallium exceed target limits, where the ingestion pathway seems to be of greater concern than dermal exposure. Exposure to radionuclides in flowback water, particularly through the inhalation route, poses a greater threat to human health than other contaminants examined in this assessment and should be the focus of risk assessment and risk mitigation efforts. PMID:29641504

Assessing Residential Exposure Risk from Spills of Flowback Water from Marcellus Shale Hydraulic Fracturing Activity.

PubMed

Abualfaraj, Noura; Gurian, Patrick L; Olson, Mira S

2018-04-11

Identifying sources of concern and risk from shale gas development, particularly from the hydraulic fracturing process, is an important step in better understanding sources of uncertainty within the industry. In this study, a risk assessment of residential exposure pathways to contaminated drinking water is carried out. In this model, it is assumed that a drinking water source is contaminated by a spill of flowback water; probability distributions of spill size and constituent concentrations are fit to historical datasets and Monte Carlo simulation was used to calculate a distribution of risk values for two scenarios: (1) use of a contaminated reservoir for residential drinking water supply and (2) swimming in a contaminated pond. The swimming scenario did not produce risks of concern from a single exposure of 1 h duration, but 11 such 1-h exposures did produce risks of 10 -6 due to radionuclide exposure. The drinking water scenario over a 30-year exposure duration produced cancer risk values exceeding 10 -6 for arsenic, benzene, benzo(a)pyrene, heptachlor, heptachlor epoxide, pentachlorophenol, and vinyl chloride. However, this extended exposure duration is probably not realistic for exposure by a spill event. Radionuclides produced risks in the residential drinking water scenario of 10 -6 in just 8 h, a much more realistic timeline for continual exposure due to a spill event. In general, for contaminants for which inhalation exposure was applicable, this pathway produced the highest risks with exposure from ingestion posing the next greatest risk to human health followed by dermal absorption (or body emersion for radionuclides). Considering non-carcinogenic effects, only barium and thallium exceed target limits, where the ingestion pathway seems to be of greater concern than dermal exposure. Exposure to radionuclides in flowback water, particularly through the inhalation route, poses a greater threat to human health than other contaminants examined in this assessment and should be the focus of risk assessment and risk mitigation efforts.

Historical reconstruction of polychlorinated biphenyl (PCB) exposures for workers in a capacitor manufacturing plant.

PubMed

Hopf, Nancy B; Ruder, Avima M; Waters, Martha A

2014-05-01

We developed a semiquantitative job exposure matrix (JEM) for workers exposed to polychlorinated biphenyls (PCBs) at a capacitor manufacturing plant from 1946 to 1977. In a recently updated mortality study, mortality of prostate and stomach cancer increased with increasing levels of cumulative exposure estimated with this JEM (trend p values = 0.003 and 0.04, respectively). Capacitor manufacturing began with winding bales of foil and paper film, which were placed in a metal capacitor box (pre-assembly), and placed in a vacuum chamber for flood-filling (impregnation) with dielectric fluid (PCBs). Capacitors dripping with PCB residues were then transported to sealing stations where ports were soldered shut before degreasing, leak testing, and painting. Using a systematic approach, all 509 unique jobs identified in the work histories were rated by predetermined process- and plant-specific exposure determinants; then categorized based on the jobs' similarities (combination of exposure determinants) into 35 job exposure categories. The job exposure categories were ranked followed by a qualitative PCB exposure rating (baseline, low, medium, and high) for inhalation and dermal intensity. Category differences in other chemical exposures (solvents, etc.) prevented further combining of categories. The mean of all available PCB concentrations (1975 and 1977) for jobs within each intensity rating was regarded as a representative value for that intensity level. Inhalation (in microgram per cubic milligram) and dermal (unitless) exposures were regarded as equally important. Intensity was frequency adjusted for jobs with continuous or intermittent PCB exposures. Era-modifying factors were applied to the earlier time periods (1946-1974) because exposures were considered to have been greater than in later eras (1975-1977). Such interpolations, extrapolations, and modifying factors may introduce non-differential misclassification; however, we do believe our rigorous method minimized misclassification, as shown by the significant exposure-response trends in the epidemiologic analysis.

Field Evaluation of Solvent-Free Sampling with Di-n-butylamine for the Determination of Airborne Monomeric and Oligomeric 1,6-Hexamethylene Diisocyanate

DTIC Science & Technology

2014-03-27

cause contact dermatitis , asthma, and hypersensitivity pneumonitis; the most common adverse health outcome associated with isocyanate exposure is...linked to allergic contact dermatitis in humans and respiratory sensitization in animals. Chronic dermal exposure has resulted in skin irritation and...derivatization stabilizes the highly reactive isocyanates and enhances recovery of the isocyanates that do not come into contact with the derivatization

Trans-Dermal Fentanyl Patches are a Cost-Effective Method of Long-Term Analgesic Delivery Following Corneal Exposure to Sulfur Mustard Vapor

DTIC Science & Technology

2012-01-01

SM) exposure in rabbits involves delivery of the opioid receptor agonist buprenorphine using subcutaneously implanted osmotic pumps. The...significantly lower than the costs of purchasing and loading an osmotic pump with buprenorphine . Pump implantation took approximately 10 min per...general distress than did the buprenorphine cohort. The elevated behavioral changes exhibited by the rabbits with implanted pumps were likely a

Development of a high-throughput screening system for identification of novel reagents regulating DNA damage in human dermal fibroblasts.

PubMed

Bae, Seunghee; An, In-Sook; An, Sungkwan

2015-09-01

Ultraviolet (UV) radiation is a major inducer of skin aging and accumulated exposure to UV radiation increases DNA damage in skin cells, including dermal fibroblasts. In the present study, we developed a novel DNA repair regulating material discovery (DREAM) system for the high-throughput screening and identification of putative materials regulating DNA repair in skin cells. First, we established a modified lentivirus expressing the luciferase and hypoxanthine phosphoribosyl transferase (HPRT) genes. Then, human dermal fibroblast WS-1 cells were infected with the modified lentivirus and selected with puromycin to establish cells that stably expressed luciferase and HPRT (DREAM-F cells). The first step in the DREAM protocol was a 96-well-based screening procedure, involving the analysis of cell viability and luciferase activity after pretreatment of DREAM-F cells with reagents of interest and post-treatment with UVB radiation, and vice versa. In the second step, we validated certain effective reagents identified in the first step by analyzing the cell cycle, evaluating cell death, and performing HPRT-DNA sequencing in DREAM-F cells treated with these reagents and UVB. This DREAM system is scalable and forms a time-saving high-throughput screening system for identifying novel anti-photoaging reagents regulating DNA damage in dermal fibroblasts.

A review of the neurotoxicity risk of selected hydrocarbon fuels.

PubMed

Ritchie, G D; Still, K R; Alexander, W K; Nordholm, A F; Wilson, C L; Rossi, J; Mattie, D R

2001-01-01

Over 1.3 million civilian and military personnel are occupationally exposed to hydrocarbon fuels, emphasizing gasoline, jet fuel, diesel fuel, or kerosene. These exposures may occur acutely or chronically to raw fuel, vapor, aerosol, or fuel combustion exhaust by dermal, respiratory inhalation, or oral ingestion routes, and commonly occur concurrently with exposure to other chemicals and stressors. Hydrocarbon fuels are complex mixtures of 150-260+ aliphatic and aromatic hydrocarbon compounds containing varying concentrations of potential neurotoxicants including benzene, n-hexane, toluene, xylenes, naphthalene, and certain n-C9-C12 fractions (n-propylbenzene, trimethylbenzene isomers). Due to their natural petroleum base, the chemical composition of different hydrocarbon fuels is not defined, and the fuels are classified according to broad performance criteria such as flash and boiling points, complicating toxicological comparisons. While hydrocarbon fuel exposures occur typically at concentrations below permissible exposure limits for their constituent chemicals, it is unknown whether additive or synergistic interactions may result in unpredicted neurotoxicity. The inclusion of up to six performance additives in existing fuel formulations presents additional neurotoxicity challenge. Additionally, exposures to hydrocarbon fuels, typically with minimal respiratory or dermal protection, range from weekly fueling of personal automobiles to waist-deep immersion of personnel in raw fuel during maintenance of aircraft fuel tanks. Occupational exposures may occur on a near daily basis for from several months to over 20 yr. A number of published studies have reported acute or persisting neurotoxic effects from acute, subchronic, or chronic exposure of humans or animals to hydrocarbon fuels, or to certain constituent chemicals of these fuels. This review summarizes human and animal studies of hydrocarbon fuel-induced neurotoxicity and neurobehavioral consequences. It is hoped that this review will support ongoing attempts to review and possibly revise exposure standards for hydrocarbon fuels.

Benzene and naphthalene in air and breath as indicators of exposure to jet fuel

PubMed Central

Egeghy, P; Hauf-Cabalo, L; Gibson, R; Rappaport, S

2003-01-01

Aims: To estimate exposures to benzene and naphthalene among military personnel working with jet fuel (JP-8) and to determine whether naphthalene might serve as a surrogate for JP-8 in studies of health effects. Methods: Benzene and naphthalene were measured in air and breath of 326 personnel in the US Air Force, who had been assigned a priori into low, moderate, and high exposure categories for JP-8. Results: Median air concentrations for persons in the low, moderate, and high exposure categories were 3.1, 7.4, and 252 µg benzene/m3 air, 4.6, 9.0, and 11.4 µg benzene/m3 breath, 1.9, 10.3, and 485 µg naphthalene/m3 air, and 0.73, 0.93, and 1.83 µg naphthalene/m3 breath, respectively. In the moderate and high exposure categories, 5% and 15% of the benzene air concentrations, respectively, were above the 2002 threshold limit value (TLV) of 1.6 mg/m3. Multiple regression analyses of air and breath levels revealed prominent background sources of benzene exposure, including cigarette smoke. However, naphthalene exposure was not unduly influenced by sources other than JP-8. Among heavily exposed workers, dermal contact with JP-8 contributed to air and breath concentrations along with several physical and environmental factors. Conclusions: Personnel having regular contact with JP-8 are occasionally exposed to benzene at levels above the current TLV. Among heavily exposed workers, uptake of JP-8 components occurs via both inhalation and dermal contact. Naphthalene in air and breath can serve as useful measures of exposure to JP-8 and uptake of fuel components in the body. PMID:14634191

Mathematical Description of the Uptake of Hydrocarbons in Jet Fuel into the Stratum Corneum of Human Volunteers

PubMed Central

Kim, David; Farthing, Matthew W.; Miller, Cass T.; Nylander-French, Leena A.

2008-01-01

The objective of this research was to develop a mathematical description of uptake of aromatic and aliphatic hydrocarbons into the stratum corneum of human skin in vivo. A simple description based on Fick’s Laws of diffusion was used to predict the spatiotemporal variation of naphthalene, 1- and 2-methylnaphthalene, undecane, and dodecane in the stratum corneum of human volunteers. The estimated values of the diffusion coefficients for each chemical were comparable to values predicted using in vitro skin systems and biomonitoring studies. These results demonstrate the value of measuring dermal exposure using the tape-strip technique and the importance of quantifying of dermal uptake. PMID:18423910

A Case–Control Study of Lung Cancer Nested in a Cohort of European Asphalt Workers

PubMed Central

Olsson, Ann; Kromhout, Hans; Agostini, Michela; Hansen, Johnni; Lassen, Christina Funch; Johansen, Christoffer; Kjaerheim, Kristina; Langård, Sverre; Stücker, Isabelle; Ahrens, Wolfgang; Behrens, Thomas; Lindbohm, Marja-Liisa; Heikkilä, Pirjo; Heederik, Dick; Portengen, Lützen; Shaham, Judith; Ferro, Gilles; de Vocht, Frank; Burstyn, Igor; Boffetta, Paolo

2010-01-01

Background We conducted a nested case–control study in a cohort of European asphalt workers in which an increase in lung cancer risk has been reported among workers exposed to airborne bitumen fume, although potential bias and confounding were not fully addressed. Objective We investigated the contribution of exposure to bitumen, other occupational agents, and tobacco smoking to the risk of lung cancer among asphalt workers. Methods Cases were cohort members in Denmark, Finland, France, Germany, the Netherlands, Norway, and Israel who had died of lung cancer between 1980 and the end of follow-up (2002–2005). Controls were individually matched in a 3:1 ratio to cases on year of birth and country. We derived exposure estimates for bitumen fume and condensate, organic vapor, and polycyclic aromatic hydrocarbons, as well as for asbestos, crystalline silica, diesel motor exhaust, and coal tar. Odds ratios (ORs) were calculated for ever-exposure, duration, average exposure, and cumulative exposure after adjusting for tobacco smoking and exposure to coal tar. Results A total of 433 cases and 1,253 controls were included in the analysis. The OR was 1.12 [95% confidence interval (CI), 0.84–1.49] for inhalation exposure to bitumen fume and 1.17 (95% CI, 0.88–1.56) for dermal exposure to bitumen condensate. No significant trend was observed between lung cancer risk and duration, average exposure, or cumulative exposure to bitumen fume or condensate. Conclusions We found no consistent evidence of an association between indicators of either inhalation or dermal exposure to bitumen and lung cancer risk. A sizable proportion of the excess mortality from lung cancer relative to the general population observed in the earlier cohort phase is likely attributable to high tobacco consumption and possibly to coal tar exposure, whereas other occupational agents do not appear to play an important role. PMID:20529766

Historical reconstruction of polychlorinated biphenyl (PCB) exposures for workers in a capacitor manufacturing plant

PubMed Central

Hopf, Nancy B.; Ruder, Avima M.; Waters, Martha A.

2015-01-01

We developed a semiquantitative job exposure matrix (JEM) for workers exposed to polychlorinated biphenyls (PCBs) at a capacitor manufacturing plant from 1946 to 1977. In a recently updated mortality study, mortality of prostate and stomach cancer increased with increasing levels of cumulative exposure estimated with this JEM (trend p values=0.003 and 0.04, respectively). Capacitor manufacturing began with winding bales of foil and paper film, which were placed in a metal capacitor box (pre-assembly), and placed in a vacuum chamber for flood-filling (impregnation) with dielectric fluid (PCBs). Capacitors dripping with PCB residues were then transported to sealing stations where ports were soldered shut before degreasing, leak testing, and painting. Using a systematic approach, all 509 unique jobs identified in the work histories were rated by predetermined process- and plant-specific exposure determinants; then categorized based on the jobs’ similarities (combination of exposure determinants) into 35 job exposure categories. The job exposure categories were ranked followed by a qualitative PCB exposure rating (baseline, low, medium, and high) for inhalation and dermal intensity. Category differences in other chemical exposures (solvents, etc.) prevented further combining of categories. The mean of all available PCB concentrations (1975 and 1977) for jobs within each intensity rating was regarded as a representative value for that intensity level. Inhalation (in microgram per cubic milligram) and dermal (unitless) exposures were regarded as equally important. Intensity was frequency adjusted for jobs with continuous or intermittent PCB exposures. Era-modifying factors were applied to the earlier time periods (1946–1974) because exposures were considered to have been greater than in later eras (1975–1977). Such interpolations, extrapolations, and modifying factors may introduce non-differential misclassification; however, we do believe our rigorous method minimized misclassification, as shown by the significant exposure–response trends in the epidemiologic analysis. PMID:23475444

Screening-Level Risk Assessment for Styrene-Acrylonitrile (SAN) Trimer Detected in Soil and Groundwater

PubMed Central

Kirman, C. R.; Gargas, M. L.; Collins, J. J.; Rowlands, J. C.

2012-01-01

A screening-level risk assessment was conducted for styrene-acrylonitrile (SAN) Trimer detected at the Reich Farm Superfund site in Toms River, NJ. Consistent with a screening-level approach, on-site and off-site exposure scenarios were evaluated using assumptions that are expected to overestimate actual exposures and hazards at the site. Environmental sampling data collected for soil and groundwater were used to estimate exposure point concentrations. Several exposure scenarios were evaluated to assess potential on-site and off-site exposures, using parameter values for exposures to soil (oral, inhalation of particulates, and dermal contact) and groundwater (oral, dermal contact) to reflect central tendency exposure (CTE) and reasonable maximum exposure (RME) conditions. Three reference dose (RfD) values were derived for SAN Trimer for short-term, subchronic, and chronic exposures, based upon its effects on the liver in exposed rats. Benchmark (BMD) methods were used to assess the relationship between exposure and response, and to characterize appropriate points of departure (POD) for each RfD. An uncertainty factor of 300 was applied to each POD to yield RfD values of 0.1, 0.04, and 0.03 mg/kg-d for short-term, subchronic, and chronic exposures, respectively. Because a chronic cancer bioassay for SAN Trimer in rats (NTP 2011a) does not provide evidence of carcinogenicity, a cancer risk assessment is not appropriate for this chemical. Potential health hazards to human health were assessed using a hazard index (HI) approach, which considers the ratio of exposure dose (i.e., average daily dose, mg/kg-d) to toxicity dose (RfD, mg/kg-d) for each scenario. All CTE and RME HI values are well below 1 (where the average daily dose is equivalent to the RfD), indicating that there is no concern for potential noncancer effects in exposed populations even under the conservative assumptions of this screening-level assessment. PMID:23030654

IRIS Toxicological Review of Benzene (Noncancer Effects) (1998 External Review Draft)

EPA Science Inventory

Benzene is a widely used as an industrial solvent, an intermediate in chemical synthesis of commercial products, and a component of gasoline. The potential for human exposure via inhalation, dermal, and oral routes is great under environmental and occupational situations. The U.S...

Research Summaries of 1989

DTIC Science & Technology

1989-01-01

INHALATION AND DERMAL EXPOSURE. NMRI REPORT. JULY 1989. 34 PP. TOXICOLOGY DETACHMENT M0096.00O.0006 (DW377025) REPORT NO.35 ADMINISTRATION INHALATION ...672 NMRI 89-0122 MADONNA GS LEDNEY GD ELLIOTT TB BROOK I ULRICH JT qYERS KR PATCHEN ML WALKER RI TREHALOSE DIMYCOLATE ENHANCES RESISTANCE TO INFECTION

A MULTI-RESIDUE METHOD FOR THE ANALYSIS OF INSECTICIDES COLLECTED ON COTTON SURFACE WIPES

EPA Science Inventory

A method was developed for the extraction, clean-up, and analysis of multiple pesticides from cotton wipe media used in human exposure studies to collect residues from residential hard surfaces. Measurements of pesticides are critical for estimating dermal and indirect ingestion ...

NHEXAS PHASE I REGION 5 STUDY--METALS IN DUST ANALYTICAL RESULTS

EPA Science Inventory

This data set includes analytical results for measurements of metals in 1,906 dust samples. Dust samples were collected to assess potential residential sources of dermal and inhalation exposures and to examine relationships between analyte levels in dust and in personal and bioma...

40 CFR 721.63 - Protection in the workplace.

Code of Federal Regulations, 2010 CFR

2010-07-01

... wear, personal protective equipment that provides a barrier to prevent dermal exposure to the substance in the specific work area where it is selected for use. Each such item of personal protective... other personal protective equipment selected in paragraph (a)(1) of this section, the following items...

INCONSISTENCIES BETWEEN CYTOKINE PROFILES, ANTIBODY RESPONSES, AND RESPIRATORY HYPERRESPONSIVENESS FOLLOWING DERMAL EXPOSURE TO ISOCYANATES

EPA Science Inventory

Cytokine profiling of local lymph node responses has been proposed as a simple test to identify chemicals, such as low molecular weight diisocyanates, that pose a significant risk of occupational asthma. Previously, we reported cytokine mRNA profiles for dinitrochlorobenzene (DNC...

78 FR 46274 - Pyroxasulfone; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-31

... following a 4-week dermal exposure producing local inflammation and systemic effects of minimal to mild...- linear approach (i.e., Reference dose (RfD)) will adequately account for all chronic toxicity, including... and other relevant data. Cancer risk is quantified using a linear or nonlinear approach. If sufficient...

AN UPDATE ON SOME ARSENIC PROJECTS AT THE UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

EPA Science Inventory

ABSTRACT Exposure to arsenic (As) has been reported to cause many adverse health effects in humans, including internal and skin cancers, vascular, neurological and dermal manifestations. Some Offices of the US Environmental Protection Agency (EPA) deal with As and selected activ...

Exposure to dust-bound PAHs and associated carcinogenic risk in primitive and traditional cooking practices in Pakistan.

PubMed

Kamal, Atif; Malik, Riffat Naseem; Martellini, Tania; Cincinelli, Alessandra

2015-08-01

The aim of this study was to determine the abundance and distribution of polycyclic aromatic hydrocarbons (PAHs) in dust samples collected from the selected professional cooking workplaces (WCs) and residential household cooking areas (WRs), where traditional and primitive cooking practices are still prevelent. Another aim of this study was to investigate the carcinogenic risk for Pakistani human exposure to dust-bound PAHs via the routes of inhalation, ingestion, and dermal contact. Generally, the concentration of individual congeners of PAHs in surface dust samples of WC sites was higher than those measured in WR sites (p < 0.05). The benzo(a)pyrene (B(a)P), a very high carcinogenic compound, was present in the dust samples from WC sites in the highest mean concentration (630 ng g(-1) dry weight (d.w.)). The BaP mean concentration in WC workplaces was almost eight times higher than the mean value found in WR exposure sites. Moreover, the average concentration of ∑PAHs, combustion origin PAHs (∑COMB) and sum total of 7-carcinogenic PAHs (∑7-carcinogens) were also significantly higher in WC dusts samples than that in WR workplaces. Principal component analysis (PCA) and diagnostic ratios suggested coal/wood combustion as major PAH emission sources in both exposure sites. The average incremental lifetime cancer risk (ILCR) suggested a moderate to potential high cancer risk for adults and children exposed to dust-bound PAHs in both exposure sites, in particular via both dermal and ingestion contact pathways.

Risk-based high-throughput chemical screening and prioritization using exposure models and in vitro bioactivity assays

DOE PAGES

Shin, Hyeong -Moo; Ernstoff, Alexi; Arnot, Jon A.; ...

2015-05-01

We present a risk-based high-throughput screening (HTS) method to identify chemicals for potential health concerns or for which additional information is needed. The method is applied to 180 organic chemicals as a case study. We first obtain information on how the chemical is used and identify relevant use scenarios (e.g., dermal application, indoor emissions). For each chemical and use scenario, exposure models are then used to calculate a chemical intake fraction, or a product intake fraction, accounting for chemical properties and the exposed population. We then combine these intake fractions with use scenario-specific estimates of chemical quantity to calculate dailymore » intake rates (iR; mg/kg/day). These intake rates are compared to oral equivalent doses (OED; mg/kg/day), calculated from a suite of ToxCast in vitro bioactivity assays using in vitro-to-in vivo extrapolation and reverse dosimetry. Bioactivity quotients (BQs) are calculated as iR/OED to obtain estimates of potential impact associated with each relevant use scenario. Of the 180 chemicals considered, 38 had maximum iRs exceeding minimum OEDs (i.e., BQs > 1). For most of these compounds, exposures are associated with direct intake, food/oral contact, or dermal exposure. The method provides high-throughput estimates of exposure and important input for decision makers to identify chemicals of concern for further evaluation with additional information or more refined models.« less

Relative source allocation of TDI to drinking water for derivation of a criterion for chloroform: a Monte-Carlo and multi-exposure assessment.

PubMed

Niizuma, Shun; Matsui, Yoshihiko; Ohno, Koichi; Itoh, Sadahiko; Matsushita, Taku; Shirasaki, Nobutaka

2013-10-01

Drinking water quality standard (DWQS) criteria for chemicals for which there is a threshold for toxicity are derived by allocating a fraction of tolerable daily intake (TDI) to exposure from drinking water. We conducted physiologically based pharmacokinetic model simulations for chloroform and have proposed an equation for total oral-equivalent potential intake via three routes (oral ingestion, inhalation, and dermal exposures), the biologically effective doses of which were converted to oral-equivalent potential intakes. The probability distributions of total oral-equivalent potential intake in Japanese people were estimated by Monte Carlo simulations. Even when the chloroform concentration in drinking water equaled the current DWQS criterion, there was sufficient margin between the intake and the TDI: the probability that the intake exceeded TDI was below 0.1%. If a criterion that the 95th percentile estimate equals the TDI is regarded as both providing protection to highly exposed persons and leaving a reasonable margin of exposure relative to the TDI, then the chloroform drinking water criterion could be a concentration of 0.11mg/L. This implies a daily intake equal to 34% of the TDI allocated to the oral intake (2L/d) of drinking water for typical adults. For the highly exposed persons, inhalation exposure via evaporation from water contributed 53% of the total intake, whereas dermal absorption contributed only 3%. Copyright © 2013 Elsevier Inc. All rights reserved.

An Exploratory Study: Assessment of Modeled Dioxin ...

EPA Pesticide Factsheets

EPA announced the availability of the final report, An Exploratory Study: Assessment of Modeled Dioxin Exposure in Ceramic Art Studios. This report investigates the potential dioxin exposure to artists/hobbyists who use ball clay to make pottery and related products. Dermal, inhalation, and ingestion exposures to clay were measured at the ceramics art department of Ohio State University in Columbus, OH. The exposure estimates were based on measured levels of clay in the studio air, deposited on surrogate food samples and on the skin of the artists. The purpose of this report is to describe an exploratory investigation of potential dioxin exposures to artists/hobbyists who use ball clay to make pottery and related products.

Irritancy and Allergic Responses Induced by Exposure to the Indoor Air Chemical 4-Oxopentanal

PubMed Central

Anderson, Stacey E.; Franko, Jennifer; Jackson, Laurel G.; Wells, J. R.; Ham, Jason E.; Meade, B. J.

2012-01-01

Over the last two decades, there has been an increasing awareness regarding the potential impact of indoor air pollution on human health. People working in an indoor environment often experience symptoms such as eye, nose, and throat irritation. Investigations into these complaints have ascribed the effects, in part, to compounds emitted from building materials, cleaning/consumer products, and indoor chemistry. One suspect indoor air contaminant that has been identified is the dicarbonyl 4-oxopentanal (4-OPA). 4-OPA is generated through the ozonolysis of squalene and several high-volume production compounds that are commonly found indoors. Following preliminary workplace sampling that identified the presence of 4-OPA, these studies examined the inflammatory and allergic responses to 4-OPA following both dermal and pulmonary exposure using a murine model. 4-OPA was tested in a combined local lymph node assay and identified to be an irritant and sensitizer. A Th1-mediated hypersensitivity response was supported by a positive response in the mouse ear swelling test. Pulmonary exposure to 4-OPA caused a significant elevation in nonspecific airway hyperreactivity, increased numbers of lung-associated lymphocytes and neutrophils, and increased interferon-γ production by lung-associated lymph nodes. These results suggest that both dermal and pulmonary exposure to 4-OPA may elicit irritant and allergic responses and may help to explain some of the adverse health effects associated with poor indoor air quality. PMID:22403157

Amphibians at risk? Susceptibility of terrestrial amphibian life stages to pesticides.

PubMed

Brühl, Carsten A; Pieper, Silvia; Weber, Brigitte

2011-11-01

Current pesticide risk assessment does not specifically consider amphibians. Amphibians in the aquatic environment (aquatic life stages or postmetamorphic aquatic amphibians) and terrestrial living juvenile or adult amphibians are assumed to be covered by the risk assessment for aquatic invertebrates and fish, or mammals and birds, respectively. This procedure has been evaluated as being sufficiently protective regarding the acute risk posed by a number of pesticides to aquatic amphibian life stages (eggs, larvae). However, it is unknown whether the exposure and sensitivity of terrestrial living amphibians are comparable to mammalian and avian exposure and sensitivity. We reviewed the literature on dermal pesticide absorption and toxicity studies for terrestrial life stages of amphibians, focusing on the dermal exposure pathway, that is, through treated soil or direct overspray. In vitro studies demonstrated that cutaneous absorption of chemicals is significant and that chemical percutaneous passage, P (cm/h), is higher in amphibians than in mammals. In vivo, the rapid and substantial uptake of the herbicide atrazine from treated soil by toads (Bufo americanus) has been described. Severe toxic effects on various amphibian species have been reported for field-relevant application rates of different pesticides. In general, exposure and toxicity studies for terrestrial amphibian life stages are scarce, and the reported data indicate the need for further research, especially in light of the global amphibian decline. Copyright © 2011 SETAC.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shin, Hyeong -Moo; Ernstoff, Alexi; Arnot, Jon A.

We present a risk-based high-throughput screening (HTS) method to identify chemicals for potential health concerns or for which additional information is needed. The method is applied to 180 organic chemicals as a case study. We first obtain information on how the chemical is used and identify relevant use scenarios (e.g., dermal application, indoor emissions). For each chemical and use scenario, exposure models are then used to calculate a chemical intake fraction, or a product intake fraction, accounting for chemical properties and the exposed population. We then combine these intake fractions with use scenario-specific estimates of chemical quantity to calculate dailymore » intake rates (iR; mg/kg/day). These intake rates are compared to oral equivalent doses (OED; mg/kg/day), calculated from a suite of ToxCast in vitro bioactivity assays using in vitro-to-in vivo extrapolation and reverse dosimetry. Bioactivity quotients (BQs) are calculated as iR/OED to obtain estimates of potential impact associated with each relevant use scenario. Of the 180 chemicals considered, 38 had maximum iRs exceeding minimum OEDs (i.e., BQs > 1). For most of these compounds, exposures are associated with direct intake, food/oral contact, or dermal exposure. The method provides high-throughput estimates of exposure and important input for decision makers to identify chemicals of concern for further evaluation with additional information or more refined models.« less

Changes of MMP-1 and collagen type Ialpha1 by UVA, UVB and IRA are differentially regulated by Trx-1.

PubMed

Buechner, Nicole; Schroeder, Peter; Jakob, Sascha; Kunze, Kerstin; Maresch, Tanja; Calles, Christian; Krutmann, Jean; Haendeler, Judith

2008-07-01

Exposure of human skin to solar radiation, which includes ultraviolet (UV) radiation (UVA and UVB) visible light and infrared radiation, induces skin aging. The effects of light have been attributed to irradiation-induced reactive oxygen species (ROS) formation, but the specific signaling pathways are not well understood. Detrimental effects of solar radiation are dermal diseases and photoaging. Exposure of cultured human dermal fibroblasts to UVA, UVB or IRA increased ROS formation in vitro. One important redox regulator is the oxidoreductase thioredoxin-1 (Trx). Trx is ubiquitously expressed and has anti-oxidative and anti-apoptotic properties. Besides its function to reduce H(2)O(2), Trx binds to and regulates transcription factors. The aim of this study was to investigate whether Trx influences the regulation of MMP-1 and collagen Ialpha1 by UVA, UVB and IRA. We irradiated human dermal fibroblasts with UVA, UVB and IRA. UVA, UVB and IRA upregulated MMP-1 expression. Trx inhibited UVA-induced MMP-1 upregulation in a NFkappaB dependent manner. UVA, UVB and IRA reduced collagen Ialpha1 expression. Incubation with Trx inhibited the effects of UVB and IRA on collagen Ialpha1 expression. In conclusion, MMP-1 and collagen Ialpha1, which play important roles in aging processes, seems to be regulated by different transcriptional mechanisms and Trx can only influence distinct signaling pathways induced by UVA, UVB and probably IRA. Thus, Trx may serve as an important contributor to an "anti-aging therapeutic cocktail".

Biological Mechanisms Underlying the Ultraviolet Radiation-Induced Formation of Skin Wrinkling and Sagging II: Over-Expression of Neprilysin Plays an Essential Role

PubMed Central

Imokawa, Genji; Nakajima, Hiroaki; Ishida, Koichi

2015-01-01

Our previous studies strongly indicated that the up-regulated activity of skin fibroblast-derived elastase plays a pivotal role in wrinkling and/or sagging of the skin via the impairment of elastic fiber configuration and the subsequent loss of skin elasticity. Fortunately, we succeeded in identifying human skin fibroblast-derived elastase as a previously known enzyme, neprilysin or neutral endopeptidase (NEP). We have also characterized epithelial-mesenchymal paracrine cytokine interactions between UVB-exposed-keratinocytes and dermal fibroblasts and found that interleukin-1α and granulocyte macrophage colony stimulatory factor (GM-CSF) are intrinsic cytokines secreted by UVB-exposed keratinocytes that stimulate the expression of neprilysin by fibroblasts. On the other hand, direct UVA exposure of human fibroblasts significantly stimulates the secretion of IL-6 and also elicits a significant increase in the gene expression of matrix metallo-protease(MMP)-1 as well as neprilysin (to a lesser extent), which is followed by distinct increases in their protein and enzymatic activity levels. Direct UVA exposure of human keratinocytes also stimulates the secretion of IL-6, IL-8 and GM-CSF but not of IL-1 and endothelin-1. These findings suggest that GM-CSF secreted by UVA-exposed keratinocytes as well as IL-6 secreted by UVA-exposed dermal fibroblasts play important and additional roles in UVA-induced sagging and wrinkling by up-regulation of neprilysin and MMP-1, respectively, in dermal fibroblasts. PMID:25856676

Development of an ex vivo BrdU labeling procedure for the murine LLNA

EPA Science Inventory

The murine local lymph node assay (LLNA) is widely used to identify chemicals that may cause allergic contact dermatitis. Exposure to a dermal sensitizer results in proliferation of local lymph node T cells, which has traditionally been measured by in vivo incorporation of [3H]m...

Lymphocyte Gene Expression Characteristic of Immediate Airway Responses (IAR) and Methacholine (MCH) Hyperresponsiveness in Mice Sensitized and Challenged with Isocyanates

EPA Science Inventory

Exposure to isocyanates has been associated with occupational airway diseases, including asthma. Previously we reported on respiratory and immune responses following dermal sensitization and intranasal challenge of BALB/c mice with 6 different isocyanates. The purpose of this st...

Associations between marine phytoplankton and symptoms of illness among recreational beachgoers in Puerto Rico, 2009

EPA Science Inventory

While phytoplankton generally have crucial roles in marine ecosystems, a small subset can release toxins and produce harmful algal blooms (HABs). HABs can be a threat to human health as symptoms from exposure range from neurological impairment to gastrointestinal (GI), dermal, a...

CONCENTRATIONS OF PESTICIDE FROM DERMAL SURFACES: A COMPARISON OF NHEXAS & AZ BORDER SAMPLES

EPA Science Inventory

NHEXAS-AZ was a statewide survey designed to gather data on the distributions of exposure from various media. Results of intensive sampling were obtained from 179 homes. Border-AZ was a similar study focusing on homes within 40 km of the Arizona-Mexico Border; similar results...

75 FR 5546 - Proposed Significant New Use Rule for Multi-walled Carbon Nanotubes

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-03

... American Industrial Classification System (NAICS) codes have been provided to assist you and others in... dermal exposure; use of the substance without a National Institute for Occupational Safety and Health... observation period of up to 3 months. Evaluation should include markers of damage, oxidant stress, cell...

"Green" synthesized and coated nanaosilver alters the membrance permeability of barrier (intestinal, brain, endothelial) cells and stimulates oxidative stress pathways in neurons.

EPA Science Inventory

Nanosilver's (nanoAg) use in medical applications and consumer products is increasing. Because of this, its "green" synthesis and surface modification with beneficial coatings are desirable. Given nanoAg's potential exposure routes (e.g., dermal, intestin...

78 FR 36671 - Acetamiprid; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-19

... one of the following methods: Federal eRulemaking Portal: http://www.regulations.gov . Follow the... validity, completeness, and reliability as well as the relationship of the results of the studies to human... toxic in acute lethality studies via the oral route of exposure and is minimally toxic via the dermal...

Toxicokinetics of the pyrethroid insecticide bifenthrin in blood and brain of the rat

EPA Science Inventory

Bifenthrin is a pyrethroid insecticide and human exposure to it can occur by oral, pulmonary and dermal routes. Pyrethroids are neurotoxic agents and it is generally believed that the parent pyrethroid is the toxic entity. The objective of this study was to assess the toxicokinet...

Predictable root recession coverage.

PubMed

Hoexter, David L

2006-01-01

Gingival recession, exposure of the tooth's root, is undesirable and, in many situations, contrary to normal physiology. Today's root coverage is predictable. With the use of an acellular dermal matrix membrane (Fasciablast), we can achieve a new blood supply and predictable coverage, with no second surgical procedure. Youth, esthetics and physiology are restored.

Tissue time course and bioavailability of the pyrethroid insecticide bifenthrin in the Long-Evans rat

EPA Science Inventory

Bifenthrin is a pyrethroid insecticide and human exposure to it can occur by oral, pulmonary and dermal routes. Pyrethroids are neurotoxic agents and it is generally believed that the parent pyrethroid is the toxic entity. This study evaluated the oral disposition and bioavaila...

DEVELOPMENT OF QUANTITATIVE STRUCTURE ACTIVITY RELATIONSHIPS TO PREDICT TOXICITY FOR A VARIETY OF HUMAN AND ECOLOGICAL ENDPOINTS

EPA Science Inventory

The number of chemicals released into the environment has significantly increased over the past few years, leading to increased risk of human exposure through inhalation, ingestion, or dermal uptake. In addition, the risk also increases with increasing toxicity of the chemical. ...

76 FR 52664 - Request for Information: Announcement of Carcinogen and Recommended Exposure Limit (REL) Policy...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-23

... in one or more experimental mammalian species as the result of any oral, respiratory or dermal... scientific evidence. In contrast, other organizations, such as the International Agency for Research on... need for more efficient and quicker means of classifying chemicals. Qualitative and semi- quantitative...

CONTROLLED, SHORT-TERM DERMAL AND INHALATION EXPOSURE TO MTBE AND DIBROMOCHLOROMETHANE

EPA Science Inventory

The oxygenate methyl tert-butyl ether (MTBE) has been added to gasoline to meet national ambient air quality standards in those parts of the US that are non-compliant for carbon monoxide. Although MTBE has provided important health benefits in terms of reduced hazardous air po...

EXPERIMENTAL METHODOLOGIES AND PRELIMINARY TRANSFER FACTOR DATA FOR ESTIMATION OF DERMAL EXPOSURES TO PARTICLES

EPA Science Inventory

Developmental efforts and experimental data are described that focused on quantifying the transfer of particles on a mass basis from indoor surfaces to human skin. Methods were developed that utilized a common fluorescein-tagged Arizona Test Dust (ATD) as a possible surrogate ...

The humoral immune response of mice exposed to simulated road paving-like asphalt fumes.

PubMed

Anderson, Stacey E; Munson, Albert E; Tomblyn, Seth; Meade, B Jean; Diotte, Nicole M

2008-07-01

Asphalt is a complex mixture of organic molecules, including polycyclic aromatic hydrocarbons (PAH), which have been reported to cause serious adverse health effects in humans. Workers in manufacturing and construction trades exposed to asphalt are potentially at risk for being exposed to asphalt fumes and PAHs. Epidemiological investigations have collected mounting evidence that chemicals found in asphalt fumes present carcinogenic and possibly immunotoxic hazards. Studies evaluating the immunotoxic effects of asphalt fume are limited due to the large number of variables associated with asphalt fume exposures. This work investigates the immuno-toxic effects of road paving-like asphalt fume by analyzing the in vivo IgM response to a T-dependent antigen after exposure to whole, vapor, and particulate phase road paving-like asphalt fumes and asphalt fume condensate. Systemic exposures via intraperitoneal injection of asphalt fume condensate (at 0.625 mg/kg) and the particulate phase (at 5 mg/kg) resulted in significant reductions in the specific spleen IgM response to SRBC. Pharyngeal aspiration of the asphalt fume condensate (at 5 mg/kg) also resulted in significant suppression of the IgM response to SRBC. A significant reduction in the specific spleen IgM activity was observed after inhalation exposure to whole asphalt fumes (35 mg/m(3)) and the vapor components (11 mg/m(3)). Dermal exposures to the asphalt fume condensate resulted in significant reductions in the total (at 50 mg/kg) and specific (at 250 mg/kg) spleen IgM response to SRBC. These results demonstrate that exposure to road paving-like asphalt fumes is immunosuppressive through systemic, respiratory, and dermal routes of exposure in a murine model and raise concerns regarding the potential for adverse immunological effects.

Determinants of captan air and dermal exposures among orchard pesticide applicators in the Agricultural Health Study.

PubMed

Hines, Cynthia J; Deddens, James A; Coble, Joseph; Kamel, Freya; Alavanja, Michael C R

2011-07-01

To identify and quantify determinants of captan exposure among 74 private orchard pesticide applicators in the Agricultural Health Study (AHS). To adjust an algorithm used for estimating pesticide exposure intensity in the AHS based on these determinants and to compare the correlation of the adjusted and unadjusted algorithms with urinary captan metabolite levels. External exposure metrics included personal air, hand rinse, and dermal patch samples collected from each applicator on 2 days in 2002-2003. A 24-h urine sample was also collected. Exposure determinants were identified for each external metric using multiple linear regression models via the NLMIXED procedure in SAS. The AHS algorithm was adjusted, consistent with the identified determinants. Mixed-effect models were used to evaluate the correlation between the adjusted and unadjusted algorithm and urinary captan metabolite levels. Consistent determinants of captan exposure were a measure of application size (kilogram of captan sprayed or application method), wearing chemical-resistant (CR) gloves and/or a coverall/suit, repairing spray equipment, and product formulation. Application by airblast was associated with a 4- to 5-fold increase in exposure as compared to hand spray. Exposure reduction to the hands, right thigh, and left forearm from wearing CR gloves averaged ∼80%, to the right and left thighs and right forearm from wearing a coverall/suit by ∼70%. Applicators using wettable powder formulations had significantly higher air, thigh, and forearm exposures than those using liquid formulations. Application method weights in the AHS algorithm were adjusted to nine for airblast and two for hand spray; protective equipment reduction factors were adjusted to 0.2 (CR gloves), 0.3 (coverall/suit), and 0.1 (both). Adjustment of application method, CR glove, and coverall weights in the AHS algorithm based on our exposure determinant findings substantially improved the correlation between the AHS algorithm and urinary metabolite levels.

Determinants of Captan Air and Dermal Exposures among Orchard Pesticide Applicators in the Agricultural Health Study

PubMed Central

Hines, Cynthia J.; Deddens, James A.; Coble, Joseph; Kamel, Freya; Alavanja, Michael C. R.

2011-01-01

Objectives: To identify and quantify determinants of captan exposure among 74 private orchard pesticide applicators in the Agricultural Health Study (AHS). To adjust an algorithm used for estimating pesticide exposure intensity in the AHS based on these determinants and to compare the correlation of the adjusted and unadjusted algorithms with urinary captan metabolite levels. Methods: External exposure metrics included personal air, hand rinse, and dermal patch samples collected from each applicator on 2 days in 2002–2003. A 24-h urine sample was also collected. Exposure determinants were identified for each external metric using multiple linear regression models via the NLMIXED procedure in SAS. The AHS algorithm was adjusted, consistent with the identified determinants. Mixed-effect models were used to evaluate the correlation between the adjusted and unadjusted algorithm and urinary captan metabolite levels. Results: Consistent determinants of captan exposure were a measure of application size (kilogram of captan sprayed or application method), wearing chemical-resistant (CR) gloves and/or a coverall/suit, repairing spray equipment, and product formulation. Application by airblast was associated with a 4- to 5-fold increase in exposure as compared to hand spray. Exposure reduction to the hands, right thigh, and left forearm from wearing CR gloves averaged ∼80%, to the right and left thighs and right forearm from wearing a coverall/suit by ∼70%. Applicators using wettable powder formulations had significantly higher air, thigh, and forearm exposures than those using liquid formulations. Application method weights in the AHS algorithm were adjusted to nine for airblast and two for hand spray; protective equipment reduction factors were adjusted to 0.2 (CR gloves), 0.3 (coverall/suit), and 0.1 (both). Conclusions: Adjustment of application method, CR glove, and coverall weights in the AHS algorithm based on our exposure determinant findings substantially improved the correlation between the AHS algorithm and urinary metabolite levels. PMID:21427168

[Physically-based model of pesticide application for risk assessment of agricultural workers].

PubMed

Rubino, F M; Mandic-Rajcevic, S; Vianello, G; Brambilla, G; Colosio, C

2012-01-01

Due to their unavoidable toxicity to non-target organisms, including man, the not of Plant Protection Products requires a thorough risk assessment to rationally advise safe use procedures and protection equipment by farmers. Most information on active substances and formulations, such as dermal absorption rates and exposure limits are available in the large body of regulatory data. Physically-based computational models can be used to forecast risk in real-life conditions (preventive assessment by 'exposure profiles'), to drive the cost-effective use of products and equipment and to understand the sources of unexpected exposure.

Chronic exposure of interleukin-13 suppress the induction of matrix metalloproteinase-1 by tumour necrosis factor α in normal and scleroderma dermal fibroblasts through protein kinase B/Akt.

PubMed

Brown Lobbins, M L; Shivakumar, B R; Postlethwaite, A E; Hasty, K A

2018-01-01

Peripheral blood mononuclear cells taken from patients with scleroderma express increased levels of interleukin (IL)-13. Moreover, the expression of matrix metalloproteinase-1 (MMP-1) from involved scleroderma skin fibroblasts is refractory to stimulation by tumour necrosis factor (TNF)-α. To elucidate the mechanism(s) involved, we examined the effect of IL-13 on TNF-α-induced MMP-1 expression in normal and scleroderma human dermal fibroblast lines and studied the involvement of serine/threonine kinase B/protein kinase B (Akt) in this response. Dermal fibroblast lines were stimulated with TNF-α in the presence of varying concentrations of IL-13. Total Akt and pAkt were quantitated using Western blot analyses. Fibroblasts were treated with or without Akt inhibitor VIII in the presence of IL-13 followed by TNF-α stimulation. MMP-1 expression was analysed by real-time polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA). Statistical analysis was performed using analysis of variance (anova) or Student's t-test. Upon TNF-α stimulation, normal dermal fibroblasts secrete more MMP-1 than systemic sclerosis (SSc) fibroblasts. This increase in MMP-1 is lost when fibroblasts are co-incubated with IL-13 and TNF-α. IL-13 induced a significant increase in levels of pAkt in dermal fibroblasts, while Akt inhibitor VIII reversed the suppressive effects of IL-13 on the response of cultured fibroblasts to TNF-α, increasing their expression of MMP-1. We show that IL-13 suppresses MMP-1 in TNF-α-stimulated normal and scleroderma dermal fibroblast. Akt inhibitor VIII is able to reverse the suppressive effect of IL-13 on MMP-1 expression and protein synthesis. Our data suggest that IL-13 regulates MMP-1 expression in response to TNF-α through an Akt-mediated pathway and may play a role in fibrotic diseases such as scleroderma. © 2017 British Society for Immunology.

Inhalation Exposure to Jet Fuel (JP8) Among U.S. Air Force Personnel

DTIC Science & Technology

2010-10-01

less Ihan 25 ft > grrater tlulII 25 I t). primary job (entranl > (IIItlldomirum.er/jireglloro > Oil /side IWllgar), (HId performillg I"Orious tasks...collect vapor samples on coconut shell chareoal in tWQ.scction (100 mg/50 mg) glass sorbcnt tubes (Anasorb; SKC Inc .. Eighty Four. Pa.) at a now...dermal JP8 exposure study (~) assessed three body surfaces, additional body regions were not assessed in this study to minimize the burden Oil study

Potential of the octanol-water partition coefficient (logP) to predict the dermal penetration behaviour of amphiphilic compounds in aqueous solutions.

PubMed

Korinth, Gintautas; Wellner, Tanja; Schaller, Karl Heinz; Drexler, Hans

2012-11-23

Aqueous amphiphilic compounds may exhibit enhanced skin penetration compared with neat compounds. Conventional models do not predict this percutaneous penetration behaviour. We investigated the potential of the octanol-water partition coefficient (logP) to predict dermal fluxes for eight compounds applied neat and as 50% aqueous solutions in diffusion cell experiments using human skin. Data for seven other compounds were accessed from literature. In total, seven glycol ethers, three alcohols, two glycols, and three other chemicals were considered. Of these 15 compounds, 10 penetrated faster through the skin as aqueous solutions than as neat compounds. The other five compounds exhibited larger fluxes as neat applications. For 13 of the 15 compounds, a consistent relationship was identified between the percutaneous penetration behaviour and the logP. Compared with the neat applications, positive logP were associated with larger fluxes for eight of the diluted compounds, and negative logP were associated with smaller fluxes for five of the diluted compounds. Our study demonstrates that decreases or enhancements in dermal penetration upon aqueous dilution can be predicted for many compounds from the sign of logP (i.e., positive or negative). This approach may be suitable as a first approximation in risk assessments of dermal exposure. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Trivalent chromium activates Rac-1 and Src and induces switch in the cell death mode in human dermal fibroblasts.

PubMed

Rudolf, Emil; Cervinka, Miroslav

2009-08-10

In this study we examined interactions between human dermal fibroblasts and chromium acetate hydroxide originating from environmental waste sediments. We show that initially exposure of fibroblasts to Cr (III) induced membrane-dependent signaling including activation of Rac1 GTPase, Src and apoptosis signal-regulating kinase 1 (ASK-1) kinases leading to increased activities of p38 and particularly Jun N-terminal kinase (JNK) and subsequent activation of caspase-3. At later treatment intervals (48-96 h), caspase-3 activity became suppressed and markedly increased lactate dehydrogenase (LDH) release was observed. Further experiments demonstrated that LDH release occurred in the presence of increased oxidative stress, extensive DNA damage, overactivation of poly(ADP-ribose)polymerase-1 (PARP-1) and depletion of ATP. Using specific inhibitors it was demonstrated that oxidative stress along with PARP-1 activity are responsible for cell death mode switch and upon their inhibition caspase-3 activity could be restored. In conclusion, Cr (III) seems to induce a biphasic response in dermal fibroblasts, with initial apoptosis switched to necrosis via increased DNA damage and resulting PARP-1 activity.

A toxicologic and dermatologic assessment of cinnamyl phenylpropyl materials when used as fragrance ingredients.

PubMed

Belsito, D; Bickers, D; Bruze, M; Calow, P; Dagli, M; Fryer, A D; Greim, H; Miyachi, Y; Saurat, J H; Sipes, I G

2011-12-01

The cinnamyl phenylpropyl fragrance ingredients are a diverse group of chemical structures that have similar metabolic and toxicity profiles. A toxicological and dermatological review of these fragrance ingredients is presented. The common characteristic structural element of cinnamyl phenylpropyl materials is an aryl substituted primary alcohol/aldehyde/ester. For high end users, calculated maximum dermal exposures vary from 0.14% to 0.72%; systemic exposures vary from 0.0002 to 0.0280 mg/kg/day. Human dermatological studies show that these materials are not generally irritants or sensitizers at lower exposures from consumer products. Reactions (0.9%) in fragrance sensitive patients were observed with 3-phenyl-1-propanol at 5% in petrolatum. The cinnamyl phenylpropyl materials had low acute toxicity and no significant toxicity in repeat dose oral or dermal toxicity studies. No mutagenic or genotoxic activity in bacteria and mammalian cell line assays was observed. The cinnamyl phenylpropyl alcohol materials participate in the same beta oxidation pathways as their parent cinnamic acid derivatives, including common routes of absorption, distribution, and metabolic detoxification, and exhibit similar toxicological endpoints. Based on the review of available data, it is concluded that these materials would not present a safety concern at current levels of use as fragrance ingredients. Copyright © 2011 Elsevier Ltd. All rights reserved.

Mortality Among Workers Exposed to Toluene Diisocyanate in the US Polyurethane Foam Industry: Update and Exposure-Response Analyses

PubMed Central

Pinkerton, Lynne E.; Yiin, James H.; Daniels, Robert D.; Fent, Kenneth W.

2017-01-01

Background Mortality among 4,545 toluene diisocyante (TDI)-exposed workers was updated through 2011. The primary outcome of interest was lung cancer. Methods Life table analyses, including internal analyses by exposure duration and cumulative TDI exposure, were conducted. Results Compared with the US population, all cause and all cancer mortality was increased. Lung cancer mortality was increased but was not associated with exposure duration or cumulative TDI exposure. In post hoc analyses, lung cancer mortality was associated with employment duration in finishing jobs, but not in finishing jobs involving cutting polyurethane foam. Conclusions Dermal exposure, in contrast to inhalational exposure, to TDI is expected to be greater in finishing jobs and may play a role in the observed increase in lung cancer mortality. Limitations include the lack of smoking data, uncertainty in the exposure estimates, and exposure estimates that reflected inhalational exposure only. PMID:27346061

Human dermal exposure to galaxolide from personal care products.

PubMed

Correia, P; Cruz, A; Santos, L; Alves, A

2013-06-01

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. © 2013 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

A MURINE MODEL FOR LOW MOLECULAR WEIGHT CHEMICALS: DIFFERENTIATION OF RESPIRATORY SENSITIZERS (TMA) FROM CONTACT SENSITIZERS (DNFB)

EPA Science Inventory

Exposure to low molecular weight (LMW) chemicals contributes to both dermal and respiratory sensitization and is an important occupational health problem. Our goal was to establish an in vivo murine model for hazard identification of LMW chemicals that have the potential to indu...

Cytotoxicity of copper (II) oxide nanoparticles in rat intestinal cells: effect of simulated gastrointestinal fluids and generation of oxidative stress

EPA Science Inventory

Metallic oxide nanoparticles (NPs) have a variety of applications in industry, medicine and commercial products. Exposure to NPs can occur by inhalation, dermal contact and oral ingestion. We have previously reported on the dose- and time-dependent cytotoxicity of CuO NPs (size...

DERMAL TRANSFER EFFICIENCY OF PESTICIDES FROM NEW, VINYL SHEET FLOORING TO DRY AND WETTED PALMS

EPA Science Inventory

The USEPA is concerned about the exposure of humans to pesticide residues contained in or on various surfaces found within the home environment. Studies have been conducted to evaluate a variety of home surfaces for surface-dislodgeable residues, which are those that are most r...

MUTAGENICITY AND MUTATION SPECTRA OF AIR AND WATER: ROLE OF GSST1-1 AND AKR GENOTYPES

EPA Science Inventory

Recent molecular epidemiology research confirms that an increased risk for bladder cancer is associated with dermal/inhalation exposure to chlorinated water (from bathing/showering and/or swimming), rather than to drinking the water, and that risk is enhanced in people carrying a...

Cladosporiosis in a tomato clownfish (Amphiprion frenatus).

PubMed

Silphaduang, U; Hatai, K; Wada, S; Noga, E

2000-06-01

Infection with Cladosporium sp., a deuteromycete, caused a deep dermal ulcer that extended to bone in a cultured tomato clownfish (Amphiprion frenatus). The infection may have been secondary to immunosuppression resulting from transport or confinement-induced stress or may have resulted from chronic exposure to copper. Reports of fungal infections in tropical marine fish are rare.

DERMAL EXPOSURE TO METHYL TERT-BUTYL ETHER (MTBE) AND DIBROMOCHLOROMETHANE (DBCM) WHILE BATHING WITH CONTAMINATED WATER

EPA Science Inventory

The oxygenate methyl tert-butyl ether (MTBE) has been added to gasoline to help meet national ambient air quality standards in those parts of the U.S. that are non-compliant for carbon monoxide. Although MTBE has provided important health benefits in terms of reduced hazardous a...

Soil or Dust for Health Risk Assessment Studies in Urban Environment.

PubMed

Gabarrón, M; Faz, A; Acosta, J A

2017-10-01

To identify the best material (soil or dust) to be selected for health-risk assessment studies, road dust and urban soil from three cities with different population densities were collected, and size fractions were analysed for metal content (Pb, Zn, Cu, Cd, Cr, Co, and Ni). Results showed similar distribution of the size particles among cities, predominating fractions between 75 and 2000 μm in road dust and particles below 75 μm in soil. Metals were mainly bound to PM10 in both soil and road dust increasing the risk of adverse health effects, overall through inhalation exposure. The risk assessment showed that the most hazardous exposure pathway was the ingestion via, followed by dermal absorption and inhalation route. Values of hazard quotient showed that the risk for children due to the ingestion and dermal absorption was higher than adults, and slightly larger at PM10 comparing to <75-μm fraction for the inhalation route. Higher risk values were found for road dust, although any hazard index or cancer risk index value did not overreach the safe value of 10 -6 .

Skin notation in the context of workplace exposure standards

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scansetti, G.; Piolatto, G.; Rubino, G.F.

1988-01-01

In the establishment of workplace exposure standards, the potential for cutaneous absorption is taken into consideration through the addition of skin notation to the relevant substance. In the TLVs Documentation (ACGIH, 1986) dermal lethal dose to 50% (LD50) or human data are the bases for the assignment of skin notation to 91 of 168 substances. For the other substances, the skin attribution seems to be based on undocumented statements in 24 (14.5%), skin effects in 13 (8%), and analogy in 7 (4%), while in the remaining 33 (20%) any reference is lacking as to the basis for notation of themore » cutaneous route of entry. Furthermore, since the established cut-off value of 2 g/kg is sometimes bypassed when a notation is added or omitted, the use of dermal LD50 is perplexing. Given the relevance of the skin notation for the validation of threshold limit values (TLVs) in the workplace, a full examination and citation of all available scientific data are recommended when establishing the TLV of substances absorbable through the skin.« less

In vitro determination of transdermal permeation of synthetic musks and estimated dermal uptake through usage of personal care products.

PubMed

Zhang, Xiaolan; Yu, Yuling; Gu, Yue; Li, Xiaojing; Zhang, Xinyu; Yu, Yingxin

2017-04-01

Synthetic musks, chemical constituents of personal care products, enter the human body through dermal contact. Elucidation of the mechanisms underlying transdermal permeation of synthetic musks should enhance our understanding of their uptake and distribution in human skin and allow accurate evaluation of associated human exposure. Here, the transdermal permeation dynamics and distribution of galaxolide (HHCB) and tonalide (AHTN) were investigated using an in vitro skin diffusion model. The transdermal permeation amounts of HHCB and AHTN increased rapidly during the first 6 h. The applied HHCB and AHTN amounts did not affect percutaneous absorption rates. HHCB and AHTN remained primarily in the stratum corneum, accounting for 70.0% and 70.3% of the totals during the 24-h period, respectively. The percutaneous absorption rate of both chemicals was ∼11%. HHCB, AHTN, musk ketone, musk xylene, and Musk-T were detected in 29 personal care products. The average total concentrations of the musks were 3990, 54.0, 17.7, and 9.8 μg g -1 in perfume, shampoo, lotion, and shower gel, respectively. Among the four product categories, HHCB was dominant (57.4%-99.6%), followed by AHTN. The data clearly indicate that polycyclic and nitro musks are most commonly used in personal care products. The total estimated dermal intake (51.6 μg kg -1 bw  day -1 ) was markedly higher than total dermal uptake (5.9 μg kg -1 bw  day -1 ) when percutaneous absorption rates of the chemicals were added into the calculation. Uptake of HHCB and AHTN via dermal contact of personal care products was significantly higher than that from dust inhalation calculated according to earlier literature data. Copyright © 2017 Elsevier Ltd. All rights reserved.

Triolein reduces MMP-1 upregulation in dermal fibroblasts generated by ROS production in UVB-irradiated keratinocytes.

PubMed

Leirós, Gustavo J; Kusinsky, Ana Gabriela; Balañá, María Eugenia; Hagelin, Karin

2017-02-01

Cytokine production and oxidative stress generated by ultraviolet radiation B (UVB) skin exposure are main factors of skin photoaging. Interleukin-6 (IL-6) produced by irradiated keratinocytes is proposed to have a role in metalloproteinases (MMPs) expression activation in dermal fibroblasts. We examined the effect of triolein treatment of UVB-irradiated keratinocytes on MMP1 (interstitial collagenase) expression response of dermal fibroblasts. We assayed UVB-irradiated keratinocytes soluble signals, mainly IL-6 and reactive oxygen species (ROS). IL-6 expression and ROS generation were assayed in UVB-irradiated keratinocytes. MMP1 mRNA expression response was assayed in fibroblasts grown in keratinocytes conditioned medium. We evaluated the effect of treating keratinocytes with triolein on IL-6 expression and ROS generation in keratinocytes, and MMP1 expression in fibroblasts. The irradiation of epidermal cells with sublethal UVB doses increased IL-6 expression and ROS generation. Conditioned culture medium collected from keratinocytes was used to culture dermal fibroblasts. MMP1 mRNA expression increase was observed in fibroblasts cultured in medium collected from UVB-irradiated keratinocytes. Triolein treatment reduced the IL-6 expression and ROS generation in keratinocytes and this effect was reflected in downregulation of MMP1 expression in fibroblasts. Triolein reduces both the expression of IL-6 and ROS generation in irradiated keratinocytes. It seems to exert an anti-inflammatory and anti-oxidative stress effect on irradiated keratinocytes that in turn reduces MMP1 expression in dermal fibroblasts. Collectively, these results indicate that triolein could act as a photoprotective agent. Copyright © 2016 Japanese Society for Investigative Dermatology. Published by Elsevier B.V. All rights reserved.

Currently used organophosphate flame retardants determined in the settled dust of masjids and hotels of Saudi Arabia, a new insight into human health implications of dust exposure.

PubMed

Ali, Nadeem; Ibrahim Ismail, Iqbal Mohammad; Kadi, Mohammad W; Salem Ali Albar, Hussain Mohammed

2018-05-23

Indoor settled dust particles are considered as an important source of human exposure to chemicals such as organophosphate flame retardants (PFRs). In recent decades the Kingdom of Saudi Arabia (KSA) has experienced tremendous growth in population, as a result the number of masjids has also increased significantly to provide sufficient space for the public to offer prayers. The hospitality industry in KSA is also expanding to cater for the ever-increasing number of pilgrims visiting the two holy cities of the kingdom. However, limited data are available on the indoor pollution of masjids and hotels. In this study, PFRs were analyzed in the settled dust collected from various hotels and masjids of Jeddah, KSA. Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) and tris(1-chloro-2-propyl) phosphate (TCPP) were the major PFRs in masjid (median = 2490 and 2055 ngg-1) and hotel (median = 2360 and 3315 ngg-1) dust, respectively. A public health risk assessment was carried out by determining the incremental lifetime cancer risk (ILCR), and daily exposure via dust ingestion, inhalation, and dermal contact of PFRs. The calculated daily exposure via dust ingestion was well below the reference dose (RfD) values, and also the calculated hazardous quotient (HQ) and carcinogenic risk were well below the risk mark. However, the ILCR for PFRs was below the reference values of USEPA, which suggested that long-term exposure to these chemicals has a limited cause for concern. The study showed that the general public is exposed to PFRs in the studied microenvironments and the major exposure routes are dermal contact and ingestion.

Measurement of the exposure of workers to pesticides*

PubMed Central

Durham, William F.; Wolfe, Homer R.

1962-01-01

There is not a single pesticide for which the interrelationships between occupational exposure by different routes, the fate of the compound in the human body, and its clinical effects are all adequately known. Results of the direct measurement of exposure to pesticides may be used in evaluating the relative hazard of different routes of exposure, different operational procedures, and different protective devices. Results of the indirect measurement of exposure may be of use for the same purpose; in addition, these indirect measures may be used in relating exposures under observed conditions to clinical effects. This paper describes and evaluates detailed procedures for the use of air samples, pads, and washes in the direct measurement of the dermal and respiratory exposure of workers to pesticides. Good methods are not available for measuring oral exposure. Any measure of the absorption, storage, physiological effect, or excretion of a compound constitutes an indirect indication of exposure to it. ImagesFIG. 2 PMID:13888659

Phthalates and polycyclic aromatic hydrocarbons (PAHs) in the indoor settled carpet dust of mosques, health risk assessment for public.

PubMed

Kadi, Mohammad W; Ali, Nadeem; Albar, Hussain Mohammed Salem Ali

2018-06-15

A number of studies have reported the occurrence of phthalates and polycyclic aromatic hydrocarbons (PAHs) in indoor settled dust from different occupational and residential settings around the world but limited studies are available from public and religious places. In recent decades Kingdom of Saudi Arabia (KSA) has experienced tremendous industrial growth especially in the petroleum industries, and as result environmental issues related with such industries have also increased but scientific data is still scarce to understand the impact on public health. Therefore, the main objective of this study was to report the phthalates and PAHs profile in the settled dust collected from various mosques of Jeddah, an important part of people living in the region, and to evaluate the health risk associated with these chemicals via dust ingestion, inhalation and dermal contact for the general public who attend mosques for prayers. Phenanthrene (500-3000 ng/g), pyrene (40-1220 ng/g), and chrysene (95-4590 ng/g) were the major PAHs and ∑ 12 PAHs concentrations ranged from 2550 to 9150 ng/g. Whereas, DEHP (

Organochlorine pesticides across the tributaries of River Ravi, Pakistan: Human health risk assessment through dermal exposure, ecological risks, source fingerprints and spatio-temporal distribution.

PubMed

Baqar, Mujtaba; Sadef, Yumna; Ahmad, Sajid Rashid; Mahmood, Adeel; Li, Jun; Zhang, Gan

2018-03-15

This study monitored the human health risks through dermal exposure, hazardous risks to ecological integrity, contamination levels, spatio-temporal distribution, and congener specific analysis of organochlorine pesticides (OCPs) across River Ravi and its three northern tributaries (Nullah Bein, Nullah Basanter and Nullah Deg). The residual levels of OCPs isomers were screened for water (n=54) and surface sediment (n=54) samples from twenty seven sampling sites in two alternate seasons (pre-monsoon and post-monsoon). The ∑OCPs concentrations ranged from 13.61 to 1992.18ng/g dry weight and 12.89 to 128.16ng/L with predominance of β-endosulfan and p,p'-DDT in sediment and water matrixes, respectively. Distribution pattern revealed significantly higher concentrations in upstream and midstream, suggesting considerable transboundary OCPs pollution. Calculated ratios of α-HCH/γ-HCH, o,p'-DDT/p,p'-DDT, (DDE+DDD)/∑DDTs and cis/trans-chlordane for water and sediments identified the fresh addition of lindane, technical DDTs and chlordane in the study area. Risk quotient (RQ) based ecological risk was found to be >1 at all studied streams during both seasons and elucidates higher risks for endosulfan (α-endosulfan) and endrin. Human health risk assessment indicated absence of hazardous (non-carcinogenic) risk through bathing in studied streams; as the hazard index values ranged from 1.09E-05 to 2.48E-02 (acceptable limit; <1). However, the calculated carcinogenic risk possessed by OCPs through dermal exposure ranged from 1.39E-10 to 1.98E-05 that highlighted the considerable carcinogenic risk associated to aldrin, dieldrin, p,p'-DDT and β-endosulfan at certain studied sites. Therefore, the high levels of ecological risk and carcinogenic human health risk had emphasized an immediate elimination of ongoing OCPs addition in the studied area. Copyright © 2017 Elsevier B.V. All rights reserved.

Brominated and phosphate flame retardants (FRs) in indoor dust from different microenvironments: Implications for human exposure via dust ingestion and dermal contact.

PubMed

Zheng, Xiaobo; Qiao, Lin; Covaci, Adrian; Sun, Runxia; Guo, Huiying; Zheng, Jing; Luo, Xiaojun; Xie, Qilai; Mai, Bixian

2017-10-01

Indoor dust has been widely used to monitor flame retardants (FRs) in indoor environment, but most studies only focused on floor dust. In the present study, FRs were examined in indoor dust from different locations. Dust from air conditioner (AC) filters, beddings, floor, and windows in bedrooms, and dust from AC filters, printer table surface, computer table surface, floor, and windows in offices were collected, respectively. Polybrominated diphenyl ether congener 209 (BDE 209) and decabromodiphenyl ethane (DBDPE) were the most abundant brominated flame retardants (BFRs), and tris(chloroisopropyl) phosphate (TCIPP), tris(1,3-dichloroisopropyl) phosphate (TDCIPP), and triphenyl phosphate (TPHP) were the most abundant phosphate flame retardants (PFRs). In bedrooms, the AC filter dust had the highest median levels of BDE 209 (536 ng/g) and DBDPE (2720 ng/g), while bed dust had the highest median levels of ΣPFRs (2750 ng/g) among dust samples. In offices, printer table dust had higher median levels of BDE 209 (1330 ng/g), DBDPE (8470 ng/g), and ΣPFRs (11,000 ng/g) than those in other dust samples. The high dust ingestion values of BDE 209, DBDPE, and individual PFR were 0.28, 1.20, and <0.01-0.32 ng/kg bw/day and 7.37, 31.2, and <0.01-4.54 ng/kg bw/day for BDE 209, DBDPE, and individual PFR for adults and toddlers, respectively. The high dermal exposure values of individual PFR during sleeping were <0.01-0.23 and <0.01-0.36 ng/kg bw/day for adults and toddlers, respectively. More human exposure pathways other than dust ingestion should be considered, such as the dermal contact with beddings and furniture. Copyright © 2017 Elsevier Ltd. All rights reserved.

Skin physiology in microgravity: a 3-month stay aboard ISS induces dermal atrophy and affects cutaneous muscle and hair follicles cycling in mice.

PubMed

Neutelings, Thibaut; Nusgens, Betty V; Liu, Yi; Tavella, Sara; Ruggiu, Alessandra; Cancedda, Ranieri; Gabriel, Maude; Colige, Alain; Lambert, Charles

2015-01-01

The Mice Drawer System (MDS) Tissue Sharing program was the longest rodent space mission ever performed. It provided 20 research teams with organs and tissues collected from mice having spent 3 months on the International Space Station (ISS). Our participation to this experiment aimed at investigating the impact of such prolonged exposure to extreme space conditions on mouse skin physiology. Mice were maintained in the MDS for 91 days aboard ISS (space group (S)). Skin specimens were collected shortly after landing for morphometric, biochemical, and transcriptomic analyses. An exact replicate of the experiment in the MDS was performed on ground (ground group (G)). A significant reduction of dermal thickness (-15%, P =0.05) was observed in S mice accompanied by an increased newly synthetized procollagen (+42%, P =0.03), likely reflecting an increased collagen turnover. Transcriptomic data suggested that the dermal atrophy might be related to an early degradation of defective newly formed procollagen molecules. Interestingly, numerous hair follicles in growing anagen phase were observed in the three S mice, validated by a high expression of specific hair follicles genes, while only one mouse in the G controls showed growing hairs. By microarray analysis of whole thickness skin, we observed a significant modulation of 434 genes in S versus G mice. A large proportion of the upregulated transcripts encoded proteins related to striated muscle homeostasis. These data suggest that a prolonged exposure to space conditions may induce skin atrophy, deregulate hair follicle cycle, and markedly affect the transcriptomic repertoire of the cutaneous striated muscle panniculus carnosus.

UVA Causes Dual Inactivation of Cathepsin B and L Underlying Lysosomal Dysfunction in Human Dermal Fibroblasts

PubMed Central

Lamore, Sarah D.; Wondrak, Georg T.

2013-01-01

Cutaneous exposure to chronic solar UVA-radiation is a causative factor in photocarcinogenesis and photoaging. Recently, we have identified the thiol-dependent cysteine-protease cathepsin B as a novel UVA-target undergoing photo-oxidative inactivation upstream of autophagic-lysosomal dysfunction in fibroblasts. In this study, we examined UVA effects on a wider range of cathepsins and explored the occurrence of UVA-induced cathepsin inactivation in other cultured skin cell types. In dermal fibroblasts, chronic exposure to non-cytotoxic doses of UVA caused pronounced inactivation of the lysosomal cysteine-proteases cathepsin B and L, effects not observed in primary keratinocytes and occurring only to a minor extent in primary melanocytes. In order to determine if UVA-induced lysosomal impairment requires single or dual inactivation of cathepsin B and/or L, we used a genetic approach (siRNA) to selectively downregulate enzymatic activity of these target cathepsins. Monitoring an established set of protein markers (including LAMP1, LC3-II, and p62) and cell ultrastructural changes detected by electron microscopy, we observed that only dual genetic antagonism (targeting both CTSB and CTSL expression) could mimic UVA-induced autophagic-lysosomal alterations, whereas single knockdown (targeting CTSB or CTSL only) did not display ‘UVA-mimetic’ effects failing to reproduce the UVA-induced phenotype. Taken together, our data demonstrate that chronic UVA inhibits both cathepsin B and L enzymatic activity and that dual inactivation of both enzymes is a causative factor underlying UVA-induced impairment of lysosomal function in dermal fibroblasts. PMID:23603447

Photobiomodulation of distinct lineages of human dermal fibroblasts: a rational approach towards the selection of effective light parameters for skin rejuvenation and wound healing

NASA Astrophysics Data System (ADS)

Mignon, Charles; Uzunbajakava, Natallia E.; Raafs, Bianca; Moolenaar, Mitchel; Botchkareva, Natalia V.; Tobin, Desmond J.

2016-03-01

Distinct lineages of human dermal fibroblasts play complementary roles in skin rejuvenation and wound healing, which makes them a target of phototherapy. However, knowledge about differential responses of specific cell lineages to different light parameters and moreover the actual molecular targets remain to be unravelled. The goal of this study was to investigate the impact of a range of parameters of light on the metabolic activity, collagen production, and cell migration of distinct lineages of human dermal fibroblasts. A rational approach was used to identify parameters with high therapeutic potential. Fibroblasts exhibited both inhibitory and cytotoxic change when exposed to a high dose of blue and cyan light in tissue culture medium containing photo-reactive species, but were stimulated by high dose red and near infrared light. Cytotoxic effects were eliminated by refreshing the medium after light exposure by removing potential ROS formed by extracellular photo-reactive species. Importantly, distinct lineages of fibroblasts demonstrated opposite responses to low dose blue light treatment when refreshing the medium after exposure. Low dose blue light treatment also significantly increased collagen production by papillary fibroblasts; high dose significantly retarded closure of the scratch wound without signs of cytotoxicity, and this is likely to have involved effects on both cell migration and proliferation. We recommend careful selection of fibroblast subpopulations and their culture conditions, a systematic approach in choosing and translating treatment parameters, and pursuit of fundamental research on identification of photoreceptors and triggered molecular pathways, while seeking effective parameters to address different stages of skin rejuvenation and wound healing.

Variations of emission characterization of PAHs emitted from different utility boilers of coal-fired power plants and risk assessment related to atmospheric PAHs.

PubMed

Wang, Ruwei; Liu, Guijian; Zhang, Jiamei

2015-12-15

Coal-fired power plants (CFPPs) represent important source of atmospheric PAHs, however, their emission characterization are still largely unknown. In this work, the concentration, distribution and gas-particle partitioning of PM10- and gas-phase PAHs in flue gas emitted from different coal-fired utility boilers were investigated. Moreover, concentration and distribution in airborne PAHs from different functional areas of power plants were studied. People's inhalatory and dermal exposures to airborne PAHs at these sites were estimated and their resultant lung cancer and skin cancer risks were assessed. Results indicated that the boiler capacity and operation conditions have significant effect on PAH concentrations in both PM10 and gas phases due to the variation of combustion efficiency, whereas they take neglected effect on PAH distributions. The wet flue gas desulphurization (WFGD) takes significant effect on the scavenging of PAH in both PM10 and gas phases, higher scavenging efficiency were found for less volatile PAHs. PAH partitioning is dominated by absorption into organic matter and accompanied by adsorption onto PM10 surface. In addition, different partitioning mechanism is observed for individual PAHs, which is assumed arising from their chemical affinity and vapor pressure. Risk assessment indicates that both inhalation and dermal contact greatly contribute to the cancer risk for CFPP workers and nearby residents. People working in workshop are exposed to greater inhalation and dermal exposure risk than people living in nearby vicinity and working office. Copyright © 2015. Published by Elsevier B.V.

Exposure to triclosan augments the allergic response to ovalbumin in a mouse model of asthma.

PubMed

Anderson, Stacey E; Franko, Jennifer; Kashon, Michael L; Anderson, Katie L; Hubbs, Ann F; Lukomska, Ewa; Meade, B Jean

2013-03-01

During the last decade, there has been a remarkable and unexplained increase in the prevalence of asthma. These studies were conducted to investigate the role of dermal exposure to triclosan, an endocrine-disrupting compound, on the hypersensitivity response to ovalbumin (OVA) in a murine model of asthma. Triclosan has had widespread use in the general population as an antibacterial and antifungal agent and is commonly found in consumer products such as soaps, deodorants, toothpastes, shaving creams, mouthwashes, and cleaning supplies. For these studies, BALB/c mice were exposed dermally to concentrations of triclosan ranging from 0.75 to 3% (0.375-1.5mg/mouse/day) for 28 consecutive days. Concordantly, mice were ip injected with OVA (0.9 µg) and aluminum hydroxide (0.5mg) on days 1 and 10 and challenged with OVA (125 µg) by pharyngeal aspiration on days 19 and 27. Compared with the animals exposed to OVA alone, increased spleen weights, OVA-specific IgE, interleukin-13 cytokine levels, and numbers of lung eosinophils were demonstrated when mice were coexposed to OVA and triclosan. Statistically significant increases in OVA-specific and nonspecific airway hyperreactivity were observed for all triclosan coexposed groups compared with the vehicle and OVA controls. In these studies, exposure to triclosan alone was not demonstrated to be allergenic; however, coexposure with a known allergen resulted in enhancement of the hypersensitivity response to that allergen, suggesting that triclosan exposure may augment the allergic responses to other environmental allergens.

A generic, cross-chemical predictive PBTK model with multiple entry routes running as application in MS Excel; design of the model and comparison of predictions with experimental results.

PubMed

Jongeneelen, Frans J; Berge, Wil F Ten

2011-10-01

Physiologically based toxicokinetic (PBTK) models are computational tools, which simulate the absorption, distribution, metabolism, and excretion of chemicals. The purpose of this study was to develop a physiologically based pharmacokinetic (PBPK) model with a high level of transparency. The model should be able to predict blood and urine concentrations of environmental chemicals and metabolites, given a certain environmental or occupational exposure scenario. The model refers to a reference human of 70 kg. The partition coefficients of the parent compound and its metabolites (blood:air and tissue:blood partition coefficients of 11 organs) are estimated by means of quantitative structure-property relationship, in which five easily available physicochemical properties of the compound are the independent parameters. The model gives a prediction of the fate of the compound, based on easily available chemical properties; therefore, it can be applied as a generic model applicable to multiple compounds. Three routes of uptake are considered (inhalation, dermal, and/or oral) as well as two built-in exercise levels (at rest and at light work). Dermal uptake is estimated by the use of a dermal diffusion-based module that considers dermal deposition rate and duration of deposition. Moreover, evaporation during skin contact is fully accounted for and related to the volatility of the substance. Saturable metabolism according to Michaelis-Menten kinetics can be modelled in any of 11 organs/tissues or in liver only. Renal tubular resorption is based on a built-in algorithm, dependent on the (log) octanol:water partition coefficient. Enterohepatic circulation is optional at a user-defined rate. The generic PBTK model is available as a spreadsheet application in MS Excel. The differential equations of the model are programmed in Visual Basic. Output is presented as numerical listing over time in tabular form and in graphs. The MS Excel application of the PBTK model is available as freeware. The accuracy of the model prediction is illustrated by simulating experimental observations. Published experimental inhalation and dermal exposure studies on a series of different chemicals (pyrene, N-methyl-pyrrolidone, methyl-tert-butylether, heptane, 2-butoxyethanol, and ethanol) were selected to compare the observed data with the model-simulated data. The examples show that the model-predicted concentrations in blood and/or urine after inhalation and/or transdermal uptake have an accuracy of within an order of magnitude. It is advocated that this PBTK model, called IndusChemFate, is suitable for 'first tier assessments' and for early explorations of the fate of chemicals and/or metabolites in the human body. The availability of a simple model with a minimum burden of input information on the parent compound and its metabolites might be a stimulation to apply PBTK modelling more often in the field of biomonitoring and exposure science.

Development and Utilization of an Ex Vivo Bromodeoxyuridine Local Lymph Node Assay (LLNA) Protocol for Assessing Potential Chemical Sensitizers

EPA Science Inventory

The murine local lymph node assay (LLNA) is widely used to identify chemicals that may cause allergic contact dermatitis. Exposure to a dermal sensitizer results in proliferation of local lymph node T cells, which has traditionally been measured by in vivo incorporation of [3H]m...

CHEMOMORPHIC ANALYSIS OF MALATHION IN SKIN LAYERS OF THE RAT: IMPLICATIONS FOR THE USE OF DERMATOPHARMACOKINETIC (DPK) TAPE STRIPPING IN EXPOSURE ASSESSMENT TO PESTICIDES

EPA Science Inventory

The dermatopharmacokinetic (DPK) method of dermal tape stripping may prove to be a valuable addition to risk assessment protocols for toxic substances as it has been for the assessment of bioequivalence and bioavailability of topical dermatologic drugs. The measurement of drug ...

In Vitro Pulmonary Toxicity Assessment of Nano-Enabled Outdoor Wood Preservatives

EPA Science Inventory

Nanoscale CuCO3 (1 - 400 nm) and CeO2 (5 - 7 nm) particles are employed as a preservative and UV coating for outdoor wood, respectively. CuCO3 and CeO2 treated outdoor wood provide a product and application with a risk of dermal and/or inhalation exposures to a mixture of nanomat...

NHEXAS PHASE I ARIZONA STUDY--STANDARD OPERATING PROCEDURE FOR PREPARATION OF DERMAL WASH FOR PESTICIDES AND METALS (BCO-L-20.0)

EPA Science Inventory

This abstract is included for completeness of documentation. The technique described in the SOP title was planned in writing the QSIP. It was subsequently not used, and the SOP was not written.

The National Human Exposure Assessment Survey (NHEXAS) is a federal interagency r...

Estimation of human percutaneous bioavailability for two novel brominated flame retardants, 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (EH-TBB) and bis(2-ethylhexyl) tetrabromophthalate (BEH-TEBP)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knudsen, Gabriel A., E-mail: gabriel.knudsen@nih.g

2-Ethylhexyl-2,3,4,5-tetrabromobenzoate (EH-TBB) and bis(2-ethylhexyl)tetrabromophthalate (BEH-TEBP) are novel brominated flame retardants used in consumer products. A parallelogram approach was used to predict human dermal absorption and flux for EH-TBB and BEH-TEBP. [{sup 14}C]-EH-TBB or [{sup 14}C]-BEH-TEBP was applied to human or rat skin at 100 nmol/cm{sup 2} using a flow-through system. Intact rats received analogous dermal doses. Treated skin was washed and tape-stripped to remove “unabsorbed” [{sup 14}C]-radioactivity after continuous exposure (24 h). “Absorbed” was quantified using dermally retained [{sup 14}C]-radioactivity; “penetrated” was calculated based on [{sup 14}C]-radioactivity in media (in vitro) or excreta + tissues (in vivo). Human skin absorbedmore » EH-TBB (24 ± 1%) while 0.2 ± 0.1% penetrated skin. Rat skin absorbed more (51 ± 10%) and was more permeable (2 ± 0.5%) to EH-TBB in vitro; maximal EH-TBB flux was 11 ± 7 and 102 ± 24 pmol-eq/cm{sup 2}/h for human and rat skin, respectively. In vivo, 27 ± 5% was absorbed and 13% reached systemic circulation after 24 h (maximum flux was 464 ± 65 pmol-eq/cm{sup 2}/h). BEH-TEBP in vitro penetrance was minimal (< 0.01%) for rat or human skin. BEH-TEBP absorption was 12 ± 11% for human skin and 41 ± 3% for rat skin. In vivo, total absorption was 27 ± 9%; 1.2% reached systemic circulation. In vitro maximal BEH-TEBP flux was 0.3 ± 0.2 and 1 ± 0.3 pmol-eq/cm{sup 2}/h for human and rat skin; in vivo maximum flux for rat skin was 16 ± 7 pmol-eq/cm{sup 2}/h. EH-TBB was metabolized in rat and human skin to tetrabromobenzoic acid. BEH-TEBP-derived [{sup 14}C]-radioactivity in the perfusion media could not be characterized. < 1% of the dose of EH-TBB and BEH-TEHP is estimated to reach the systemic circulation following human dermal exposure under the conditions tested. Chemical compounds studied in this article: 2-Ethylhexyl 2,3,4,5-tetrabromobenzoate (PubChem CID: 71316600; CAS No. 183658-27-7 FW: 549.92 g/mol logP{sub est}: 7.73–8.75 (12)) Abdallah et al., 2015a. Other published abbreviations for 2-ethylhexyl-2,3,4,5-tetrabromobenzoate are TBB EHTeBB or EHTBB Abdallah and Harrad, 2011. bis(2-ethylhexyl) tetrabromophthalate (PubChem CID: 117291; CAS No. 26040-51-7 FW: 706.14 g/mol logP{sub est}: 9.48-11.95 (12)). Other published abbreviations for bis(2-ethylhexyl)tetrabromophthalate are TeBrDEPH TBPH or BEHTBP. - Highlights: • Human skin maximal flux was 11 ± 7 (EH-TBB) & 0.3 ± 0.2 (BEH-TEBP) pmol-eq/cm{sup 2}/h. • Predicted systemic bioavailability was < 1% for either chemical after 24 h. • Skin retained EH-TBB & BEH-TEBP after 24 h dermal exposure. • EH-TBB was hydrolyzed to tetrabromobenzoic acid; BEH-TEBP was not metabolized. • Skin contact is an important route of human exposure to EH-TBB & BEH-TEBP.« less

Detection of Multi-walled Carbon Nanotubes and Carbon Nanodiscs on Workplace Surfaces at a Small-Scale Producer.

PubMed

Hedmer, Maria; Ludvigsson, Linus; Isaxon, Christina; Nilsson, Patrik T; Skaug, Vidar; Bohgard, Mats; Pagels, Joakim H; Messing, Maria E; Tinnerberg, Håkan

2015-08-01

The industrial use of novel-manufactured nanomaterials such as carbon nanotubes and carbon nanodiscs is increasing globally. Occupational exposure can occur during production, downstream use, and disposal. The health effects of many nanomaterials are not yet fully characterized and to handle nano-objects, their aggregates and agglomerates >100nm (NOAA), a high degree of control measures and personal protective equipment are required. The emission of airborne NOAA during production and handling can contaminate workplace surfaces with dust, which can be resuspended resulting in secondary inhalation exposures and dermal exposures. This study surveys the presence of carbon-based nanomaterials, such as multi-walled carbon nanotubes (MWCNTs) and carbon nanodiscs, as surface contamination at a small-scale producer using a novel tape sampling method. Eighteen different surfaces at a small-scale producer were sampled with an adhesive tape sampling method. The surfaces selected were associated with the production and handling of MWCNT powder in the near-field zone. Surfaces in the far-field zone were also sampled. In addition, tape stripping of the skin was performed on one worker. The tape samples were analysed with scanning electron microscopy to detect the carbon-based NOAA. Air sampling with a personal impactor was also performed on a worker who was producing MWCNTs the same day as the tape samples were collected. MWCNTs were detected in 50% of the collected tape samples and carbon nanodiscs in 17%. MWCNTs and carbon nanodiscs were identified in all parts of the workplace, thus, increasing the risk for secondary inhalation and dermal exposure of the workers. Both airborne MWCNTs and carbon nanodiscs were detected in the personal impactor samples. The tape-strip samples from the worker showed no presence of carbon-containing nanoparticles. Tape sampling is a functional method for detecting surface contamination of carbon-based NOAA and for exposure control during production at potentially any workplace that produces or handles such manufactured nanomaterials. With the tape method, it is possible to monitor if a potential for secondary inhalation exposure or dermal exposure exists through resuspension of dust deposited on workplace surfaces. By means of air sampling, we could confirm that carbon nanodiscs were resuspended into the air at the workplace even though they were not handled during that particular work shift. MWCNTs were detected in the air samples, but can have been derived from either resuspension or from the work tasks with MWCNTs that were performed during the air sampling. Tape sampling is a complementary method to air sampling and together these two methods provide a better view of the hygienic situation in workplaces where NOAA can be emitted into work environments. © The Author 2015. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Environmental footprint of pharmaceuticals: the significance of factors beyond direct excretion to sewers.

PubMed

Daughton, Christian G; Ruhoy, Ilene S

2009-12-01

The combined excretion of active pharmaceutical ingredients (APIs) via urine and feces is considered the primary route by which APIs from human pharmaceuticals enter the environment. Disposal of unwanted, leftover medications by flushing into sewers has been considered a secondary route-one that does not contribute substantially to overall environmental loadings. The present study presents the first comprehensive examination of secondary routes of API release to the environment and for direct but unintentional human exposure. These include bathing, washing, and laundering, all of which release APIs remaining on the skin from the use of high-content dermal applications or from excretion to the skin via sweating, and disposal of unused and partially used high-content devices. Also discussed are the health hazards associated with: partially used devices, medication disposal practices of consumers, and interpersonal dermal transfer of API residues. Understanding these secondary routes is important from the perspective of pollution prevention, because actions can be designed more easily for reducing the environmental impact of APIs compared with the route of direct excretion (via urine and feces), for reducing the incidence of unintentional and purposeful poisonings of humans and pets, and for improving the quality and cost-effectiveness of health care. Overall, unintentional exposure to APIs for humans via these routes is possibly more important than exposure to trace residues recycled from the environment in drinking water or foods.

Explicit formula of finite difference method to estimate human peripheral tissue temperatures during exposure to severe cold stress.

PubMed

Khanday, M A; Hussain, Fida

2015-02-01

During cold exposure, peripheral tissues undergo vasoconstriction to minimize heat loss to preserve the maintenance of a normal core temperature. However, vasoconstricted tissues exposed to cold temperatures are susceptible to freezing and frostbite-related tissue damage. Therefore, it is imperative to establish a mathematical model for the estimation of tissue necrosis due to cold stress. To this end, an explicit formula of finite difference method has been used to obtain the solution of Pennes' bio-heat equation with appropriate boundary conditions to estimate the temperature profiles of dermal and subdermal layers when exposed to severe cold temperatures. The discrete values of nodal temperature were calculated at the interfaces of skin and subcutaneous tissues with respect to the atmospheric temperatures of 25 °C, 20 °C, 15 °C, 5 °C, -5 °C and -10 °C. The results obtained were used to identify the scenarios under which various degrees of frostbite occur on the surface of skin as well as the dermal and subdermal areas. The explicit formula of finite difference method proposed in this model provides more accurate predictions as compared to other numerical methods. This model of predicting tissue temperatures provides researchers with a more accurate prediction of peripheral tissue temperature and, hence, the susceptibility to frostbite during severe cold exposure. Copyright © 2014 Elsevier Ltd. All rights reserved.

Dermal uptake and percutaneous penetration of ten flame retardants in a human skin ex vivo model.

PubMed

Frederiksen, Marie; Vorkamp, Katrin; Jensen, Niels Martin; Sørensen, Jens Ahm; Knudsen, Lisbeth E; Sørensen, Lars S; Webster, Thomas F; Nielsen, Jesper B

2016-11-01

The dermal uptake and percutaneous penetration of ten organic flame retardants was measured using an ex vivo human skin model. The studied compounds were DBDPE, BTBPE, TBP-DBPE, EH-TBB, BEH-TEBP, α, β and γ-HBCDD as well as syn- and anti-DDC-CO. Little or none of the applied flame retardants was recovered in either type of the receptor fluids used (physiological and worst-case). However, significant fractions were recovered in the skin depot, particularly in the upper skin layers. The primary effect of the worst-case receptor fluid was deeper penetration into the skin. The recovered mass was used to calculate lower- and upper-bound permeability coefficients kp. Despite large structural variation between the studied compounds, a clear, significant decreasing trend of kp was observed with increasing log Kow. The results indicate that the dermis may provide a significant barrier for these highly lipophilic compounds. However, based on our results, dermal uptake should be considered in exposure assessments, though it may proceed in a time-lagged manner compared to less hydrophobic compounds. Copyright © 2016 Elsevier Ltd. All rights reserved.

Recreational swimmers' exposure to Vibrio vulnificus and Vibrio parahaemolyticus in the Chesapeake Bay, Maryland, USA.

PubMed

Shaw, Kristi S; Sapkota, Amy R; Jacobs, John M; He, Xin; Crump, Byron C

2015-01-01

Vibrio vulnificus and Vibrio parahaemolyticus are ubiquitous in the marine-estuarine environment, but the magnitude of human non-ingestion exposure to these waterborne pathogens is largely unknown. We evaluated the magnitude of dermal exposure to V. vulnificus and V. parahaemolyticus among swimmers recreating in Vibrio-populated waters by conducting swim studies at four swimming locations in the Chesapeake Bay in 2009 and 2011. Volunteers (n=31) swam for set time periods, and surface water (n=25) and handwash (n=250) samples were collected. Samples were analyzed for Vibrio concentrations using quantitative PCR. Linear and logistic regressions were used to evaluate factors associated with recreational exposures. Mean surface water V. vulnificus and V. parahaemolyticus concentrations were 1128CFUmL(-1) (95% confidence interval (CI): 665.6, 1591.4) and 18CFUmL(-1) (95% CI: 9.8, 26.1), respectively, across all sampling locations. Mean Vibrio concentrations in handwash samples (V. vulnificus, 180CFUcm(-2) (95% CI: 136.6, 222.5); V. parahaemolyticus, 3CFUcm(-2) (95% CI: 2.4, 3.7)) were significantly associated with Vibrio concentrations in surface water (V. vulnificus, p<0.01; V. parahaemolyticus, p<0.01), but not with salinity or temperature (V. vulnificus, p=0.52, p=0.17; V. parahaemolyticus, p=0.82, p=0.06). Handwashing reduced V. vulnificus and V. parahaemolyticus on subjects' hands by approximately one log (93.9%, 89.4%, respectively). It can be concluded that when Chesapeake Bay surface waters are characterized by elevated concentrations of Vibrio, swimmers and individuals working in those waters could experience significant dermal exposures to V. vulnificus and V. parahaemolyticus, increasing their risk of infection. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

PubMed

Shi, Leimeng; Gao, Yuan; Zhang, Haijun; Geng, Ningbo; Xu, Jiazhi; Zhan, Faqiang; Ni, Yuwen; Hou, Xiaohong; Chen, Jiping

2017-04-01

Levels and distribution of short- and medium-chain chlorinated paraffins (SCCPs and MCCPs) were measured in indoor dusts from malls in China. The concentrations of SCCPs and MCCPs in dustfalls from a building material mall ranged from 6.0 to 361.4 μg g -1 and from 5.0 to 285.9 μg g -1 , respectively. Much heavier contamination was found in central air conditioner filter (CACF) dusts from a newly opened shopping mall, with SCCP concentrations of 114.7-707.0 μg g -1 and MCCP concentrations of 89.0-1082.9 μg g -1 . The C 13 - and C 14 -CPs were the dominant congeners, while the Cl 7 and Cl 8 groups were the major chlorine congeners in both kinds of dust samples. Significant correlation relationships (p ≤ 0.05) were found between ∑SCCPs and ∑MCCPs in CACF dusts and dustfalls. Varied exposure pathways including dust ingestion and dermal permeation have been evaluated. The average daily exposure doses of SCCPs and MCCPs for the adult in CACF dusts and dustfalls were estimated to be 0.394 and 0.150 μg kg -1  day -1 , respectively. The toddler had higher exposure risks with 5.918 and 2.658 μg kg -1  day -1 in the shopping and building material malls, respectively. Dermal permeation was the predominated exposure pathway for the adult, while dust ingestion was suggested to be more important for the toddler due to hand-to-mouth contact. Copyright © 2017 Elsevier Ltd. All rights reserved.

Determination of heavy metals in indoor dust from Istanbul, Turkey: estimation of the health risk.

PubMed

Kurt-Karakus, Perihan Binnur

2012-12-01

Levels of eight potentially toxic heavy metals in indoor dust from homes and offices in Istanbul were investigated. The concentrations of heavy metals in indoor dust from homes+office ranged from 62 to 1800 μgg(-1) for Cu, 3-200 μgg(-1) for Pb, 0.4-20 μgg(-1) for Cd, 210-2800 μgg(-1) for Zn, 2.8-460μgg(-1) for Cr, 8-1300μgg(-1) for Mn, 2.4-25μgg(-1) for Co, 120-2600μgg(-1) for Ni. Results of the study were comparable to other studies conducted on indoor dust and street dust from a variety of cities globally. Considering only ingestion + inhalation, the carcinogenic risk level of Cr for adults and children (3.7×10(-5) and 2.7×10(-5)) in Istanbul was in the range of EPA's safe limits (1×10(-6) and 1×10(-4)), indicating that cancer risk of Cr due to exposure to indoor dust in Istanbul can be acceptable. According to calculated Hazard Quotient (HQ), for non-cancer effects, the ingestion of indoor dust appears to be the major route of exposure to the indoor dust that results in a higher risk for heavy metals, followed by dermal contact and inhalation pathways. However, compared to ingestion and dermal contact exposure, exposure through inhalation is almost negligible. Hazard Index (HI) values for all studied elements were lower than safe limit of 1 and this result suggested that none of the population groups would likely to experience potential health risk due to exposure to heavy metals from indoor dust in the study area. Copyright © 2012 Elsevier Ltd. All rights reserved.

An Evaluation of the Relationship among Urine, Air, and Hand Measures of Exposure to Bisphenol A (BPA) in US Manufacturing Workers.

PubMed

Hines, Cynthia J; Christianson, Annette L; Jackson, Matthew V; Ye, Xiaoyun; Pretty, Jack R; Arnold, James E; Calafat, Antonia M

2018-06-13

Exposure to bisphenol A (BPA) can be assessed using external and internal exposure measures. We examined the relationship between two measures of external BPA exposure (air and hand-wipe samples) and one of internal exposure (total BPA in urine) for a group of US manufacturing workers. During 2013-2014, we recruited 78 workers from six US companies that made BPA or made products with BPA. We quantified BPA in seven urine samples, two full-shift air samples and in pre- and end-shift hand-wipe samples collected from workers over 2 consecutive days. We examined correlations between creatinine-corrected urinary concentrations of total BPA (total BPACR) and BPA levels in air and hand wipes using Pearson's correlation coefficient. We also applied mixed-effects regression models to examine the relationship between total BPACR with BPA in air (urine~air model) and with BPA in end-shift hand wipes (urine~hand model), separately and together (urine~air+hand model), after adjusting for covariates. End-shift total BPACR strongly correlated with BPA in air (rp = 0.79, P < 0.0001) and nearly as strongly with BPA in end-shift hand wipes (rp = 0.75, P < 0.0001). In mixed-effect models, BPA air concentration and end-shift hand-wipe BPA level were significantly and positively associated with end-shift total BPACR (P < 0.0001 each). We found a significant effect of the Day 1 BPA air concentration on Day 2 total BPACR (P = 0.0104). When BPA air concentration and end-shift hand-wipe BPA level were in the same model, the air concentration (P < 0.0001) was more significant than the hand-wipe level (P = 0.0106). BPA levels in air and end-shift hand wipes strongly correlated with total BPACR, suggesting that both inhalation and dermal contract were likely exposure routes; however, inhalation, on average, appeared to be a more dominant exposure route than dermal contact for these manufacturing workers.

2,4-Dinitroanisole (DNAN) (2014).

PubMed

2018-01-01

2,4-dinitroanisole (DNAN) is a warhead explosive currently under investigation as a replacement for TNT in melt-cast insensitive munitions. In animal studies, DNAN is a mild ocular and skin irritant with a significant potential for dermal absorption.  It is not a dermal sensitizer.  Acute and subacute rat inhalation studies demonstrated minimal toxicity with LC 50 and LOAEL endpoints of 2.9 and 150 mg/m 3 , respectively.  In rat oral toxicity studies (14 and 90 days) organ weight and clinical chemistry changes suggested hepatocellular injury and anemia, particularly in females.  In males there was evidence of testicular injury at the high-dose level (80 mg/kg/day).  The NOAELs for the 14- and 90-day studies were 25 and 5 mg/kg/day, respectively, with a calculated BMDL 10 value of 0.93 mg/kg/day.  No chronic, carcinogenicity or reproductive/developmental toxicity data were available for DNAN, but a maternal and fetal NOAEL of 5.1 mg/kg/day was inferred.  DNAN is considered non-mutagenic and non-genotoxic.  It is metabolized in vivo to 2,4-dinitrophenol (DNP), but other details of its metabolism or pharmacokinetics are unknown.  There are considerable toxicity data for DNP, a known un-coupler of oxidative phosphorylation among other things, and these data may further inform regarding the safety of DNAN.  In humans, DNAN was a component of louse powder (prior to DDT) with no reported safety concerns.  However, its handling and use as a munition component presents a potential occupational hazard by both inhalation and dermal routes of exposure.  Considering both DNAN and DNP toxicity endpoints, the recommended Workplace Environmental Exposure limit for DNAN is 0.1 mg/m 2 (8-h time weighted average).

Jet Fuel Exposure and Neurological Health in Military Personnel

DTIC Science & Technology

2011-07-01

and dermal samples E Absorbed Dose measure: Exhaled breath, urine , blood F Lifestyle factors (smoking), use of protective equipment (gloves...toluene, ethylbenzene, xylene, and naphthalene. To assess personal absorbed dose levels to JP8 components, exhaled breath and urine samples were...the following primary analytes of interest were measured: benzene, toluene, ethylbenzene, xylene, and naphthalene. Pre- and post- shift urine samples

Occupational and environmental hazard assessments for the isolation, purification and toxicity testing of cyanobacterial toxins

PubMed Central

2009-01-01

Cyanobacteria can produce groups of structurally and functionally unrelated but highly potent toxins. Cyanotoxins are used in multiple research endeavours, either for direct investigation of their toxicologic properties, or as functional analogues for various biochemical and physiological processes. This paper presents occupational safety guidelines and recommendations for personnel working in field, laboratory or industrial settings to produce and use purified cyanotoxins and toxic cyanobacteria, from bulk harvesting of bloom material, mass culture of laboratory isolates, through routine extraction, isolation and purification. Oral, inhalational, dermal and parenteral routes are all potential occupational exposure pathways during the various stages of cyanotoxin production and application. Investigation of toxicologic or pharmacologic properties using in vivo models may present specific risks if radiolabelled cyanotoxins are employed, and the potential for occupational exposure via the dermal route is heightened with the use of organic solvents as vehicles. Inter- and intra-national transport of living cyanobacteria for research purposes risks establishing feral microalgal populations, so disinfection of culture equipment and destruction of cells by autoclaving, incineration and/or chlorination is recommended in order to prevent viable cyanobacteria from escaping research or production facilities. PMID:19925679

Photoprotective Potential of Penta-O-Galloyl-β-DGlucose by Targeting NF-κB and MAPK Signaling in UVB Radiation-Induced Human Dermal Fibroblasts and Mouse Skin.

PubMed

Kim, Byung-Hak; Choi, Mi Sun; Lee, Hyun Gyu; Lee, Song-Hee; Noh, Kum Hee; Kwon, Sunho; Jeong, Ae Jin; Lee, Haeri; Yi, Eun Hee; Park, Jung Youl; Lee, Jintae; Joo, Eun Young; Ye, Sang-Kyu

2015-11-01

Exposure of the skin to ultraviolet radiation can cause skin damage with various pathological changes including inflammation. In the present study, we identified the skin-protective activity of 1,2,3,4,6-penta-O-galloyl-β-D-glucose (pentagalloyl glucose, PGG) in ultraviolet B (UVB) radiation-induced human dermal fibroblasts and mouse skin. PGG exhibited antioxidant activity with regard to intracellular reactive oxygen species (ROS) generation as well as ROS and reactive nitrogen species (RNS) scavenging. Furthermore, PGG exhibited anti-inflammatory activity, inhibiting the activation of nuclear factor-kappaB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling, resulting in inhibition of the expression of pro-inflammatory mediators. Topical application of PGG followed by chronic exposure to UVB radiation in the dorsal skin of hairless mice resulted in a significant decrease in the progression of inflammatory skin damages, leading to inhibited activation of NF-κB signaling and expression of pro-inflammatory mediators. The present study demonstrated that PGG protected from skin damage induced by UVB radiation, and thus, may be a potential candidate for the prevention of environmental stimuli-induced inflammatory skin damage.

Principles for identification of High Potency Category Chemicals for which the Dermal Sensitisation Threshold (DST) approach should not be applied.

PubMed

Roberts, David W; Api, Anne Marie; Safford, Robert J; Lalko, Jon F

2015-08-01

An essential step in ensuring the toxicological safety of chemicals used in consumer products is the evaluation of their skin sensitising potential. The sensitising potency, coupled with information on exposure levels, can be used in a Quantitative Risk Assessment (QRA) to determine an acceptable level of a given chemical in a given product. Where consumer skin exposure is low, a risk assessment can be conducted using the Dermal Sensitisation Threshold (DST) approach, avoiding the need to determine potency experimentally. Since skin sensitisation involves chemical reaction with skin proteins, the first step in the DST approach is to assess, on the basis of the chemical structure, whether the chemical is expected to be reactive or not. Our accompanying publication describes the probabilistic derivation of a DST of 64 μg/cm(2) for chemicals assessed as reactive. This would protect against 95% of chemicals assessed as reactive, but the remaining 5% would include chemicals with very high potency. Here we discuss the chemical properties and structural features of high potency sensitisers, and derive an approach whereby they can be identified and consequently excluded from application of the DST. Copyright © 2015 Elsevier Inc. All rights reserved.

Exposure to Triclosan Augments the Allergic Response to Ovalbumin in a Mouse Model of Asthma

PubMed Central

Anderson, Stacey E.; Franko, Jennifer; Kashon, Michael L.; Anderson, Katie L.; Hubbs, Ann F.; Lukomska, Ewa; Meade, B. Jean

2015-01-01

During the last decade, there has been a remarkable and unexplained increase in the prevalence of asthma. These studies were conducted to investigate the role of dermal exposure to triclosan, an endocrine-disrupting compound, on the hypersensitivity response to ovalbumin (OVA) in a murine model of asthma. Triclosan has had widespread use in the general population as an antibacterial and antifungal agent and is commonly found in consumer products such as soaps, deodorants, toothpastes, shaving creams, mouthwashes, and cleaning supplies. For these studies, BALB/c mice were exposed dermally to concentrations of triclosan ranging from 0.75 to 3% (0.375–1.5 mg/mouse/day) for 28 consecutive days. Concordantly, mice were ip injected with OVA (0.9 μg) and aluminum hydroxide (0.5 mg) on days 1 and 10 and challenged with OVA (125 μg) by pharyngeal aspiration on days 19 and 27. Compared with the animals exposed to OVA alone, increased spleen weights, OVA-specific IgE, interleukin-13 cytokine levels, and numbers of lung eosinophils were demonstrated when mice were coexposed to OVA and triclosan. Statistically significant increases in OVA-specific and nonspecific airway hyperreactivity were observed for all triclosan coexposed groups compared with the vehicle and OVA controls. In these studies, exposure to triclosan alone was not demonstrated to be allergenic; however, coexposure with a known allergen resulted in enhancement of the hypersensitivity response to that allergen, suggesting that triclosan exposure may augment the allergic responses to other environmental allergens. PMID:23192912

Triclosan Induces Thymic Stromal Lymphopoietin in Skin Promoting Th2 Allergic Responses

PubMed Central

Marshall, Nikki B.; Lukomska, Ewa; Long, Carrie M.; Kashon, Michael L.; Sharpnack, Douglas D.; Nayak, Ajay P.; Anderson, Katie L.; Meade, B. Jean; Anderson, Stacey E.

2016-01-01

Triclosan is an antimicrobial chemical incorporated into many personal, medical and household products. Approximately, 75% of the U.S. population has detectable levels of triclosan in their urine, and although it is not typically considered a contact sensitizer, recent studies have begun to link triclosan exposure with augmented allergic disease. We examined the effects of dermal triclosan exposure on the skin and lymph nodes of mice and in a human skin model to identify mechanisms for augmenting allergic responses. Triclosan (0%–3%) was applied topically at 24-h intervals to the ear pinnae of OVA-sensitized BALB/c mice. Skin and draining lymph nodes were evaluated for cellular responses and cytokine expression over time. The effects of triclosan (0%–0.75%) on cytokine expression in a human skin tissue model were also examined. Exposure to triclosan increased the expression of TSLP, IL-1β, and TNF-α in the skin with concomitant decreases in IL-25, IL-33, and IL-1α. Similar changes in TSLP, IL1B, and IL33 expression occurred in human skin. Topical application of triclosan also increased draining lymph node cellularity consisting of activated CD86+GL-7+ B cells, CD80+CD86+ dendritic cells, GATA-3+OX-40+IL-4+IL-13+ Th2 cells and IL-17 A+ CD4 T cells. In vivo antibody blockade of TSLP reduced skin irritation, IL-1β expression, lymph node cellularity, and Th2 responses augmented by triclosan. Repeated dermal exposure to triclosan induces TSLP expression in skin tissue as a potential mechanism for augmenting allergic responses. PMID:26048654

PM2.5 pollution from household solid fuel burning practices in central India: 1. Impact on indoor air quality and associated health risks.

PubMed

Matawle, Jeevan Lal; Pervez, Shamsh; Shrivastava, Anjali; Tiwari, Suresh; Pant, Pallavi; Deb, Manas Kanti; Bisht, Diwan Singh; Pervez, Yasmeen F

2017-10-01

PM 2.5 concentrations were measured in residential indoor environment in slums of central India during 2012-2013. In addition, a suite of chemical components including metals (Al, K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Cd, Pb, Mo, Se, Sb, Na, Mg, K and Hg), ions (Na + , Mg 2+ , K + , Ca 2+ , F - , Cl - , NH 4 + , NO 3 - and SO 4 2- ) and carbon (OC and EC) were analyzed for all samples. Indoor PM 2.5 concentrations were found to be several folds higher than the 24-h national ambient air quality standard (60 µg/m 3 ) for PM 2.5 in India, and the concentrations were found to vary from season to season. Mass closure was attempted for PM 2.5 data, and close to 100 % mass was accounted for by organic matter, crustal material, secondary organic and inorganic aerosols and elemental carbon. Additionally, carcinogenic and non-carcinogenic health risks associated with exposure to indoor PM 2.5 (inhalation, dermal and ingestion) were estimated and while exposures associated with dermal contact and ingestion were found to be within the acceptable limits, risk associated with inhalation exposure was found to be high for children and adults. Elements including Al, Cd, Co, Cr, Mn, Ni, As and Pb were present in high concentrations and contributed to carcinogenic and non-carcinogenic risks for residents' health. Results from this study highlight the need for efforts to reduce air pollution exposure in slum areas.

Children's exposure assessment: a review of factors influencing Children's exposure, and the data available to characterize and assess that exposure.

PubMed Central

Cohen Hubal, E A; Sheldon, L S; Burke, J M; McCurdy, T R; Berry, M R; Rigas, M L; Zartarian, V G; Freeman, N C

2000-01-01

We review the factors influencing children's exposure to environmental contaminants and the data available to characterize and assess that exposure. Children's activity pattern data requirements are demonstrated in the context of the algorithms used to estimate exposure by inhalation, dermal contact, and ingestion. Currently, data on children's exposures and activities are insufficient to adequately assess multimedia exposures to environmental contaminants. As a result, regulators use a series of default assumptions and exposure factors when conducting exposure assessments. Data to reduce uncertainty in the assumptions and exposure estimates are needed to ensure chemicals are regulated appropriately to protect children's health. To improve the database, advancement in the following general areas of research is required: identification of appropriate age/developmental benchmarks for categorizing children in exposure assessment; development and improvement of methods for monitoring children's exposures and activities; collection of activity pattern data for children (especially young children) required to assess exposure by all routes; collection of data on concentrations of environmental contaminants, biomarkers, and transfer coefficients that can be used as inputs to aggregate exposure models. PMID:10856019

Natural and Sun-Induced Aging of Human Skin

PubMed Central

Rittié, Laure; Fisher, Gary J.

2015-01-01

With worldwide expansion of the aging population, research on age-related pathologies is receiving growing interest. In this review, we discuss current knowledge regarding the decline of skin structure and function induced by the passage of time (chronological aging) and chronic exposure to solar UV irradiation (photoaging). Nearly every aspect of skin biology is affected by aging. The self-renewing capability of the epidermis, which provides vital barrier function, is diminished with age. Vital thermoregulation function of eccrine sweat glands is also altered with age. The dermal collagenous extracellular matrix, which comprises the bulk of skin and confers strength and resiliency, undergoes gradual fragmentation, which deleteriously impacts skin mechanical properties and dermal cell functions. Aging also affects wound repair, pigmentation, innervation, immunity, vasculature, and subcutaneous fat homeostasis. Altogether, age-related alterations of skin lead to age-related skin fragility and diseases. PMID:25561721

Health assessment for Kaiser Aluminum and Chemical Corporation, Mead, Spokane County, Washington, Region 10. CERCLIS No. WAD000065508. Preliminary report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1989-04-12

The 240-acre Kaiser Aluminum Site is on the National Priorities List. The plant was built in 1942 as an aluminum-reduction facility. Concentrations of cyanide (total) in the river range from 0.011 to 1.7 parts per million (ppm) and free cyanide concentrations ranged from non-detected (ND) to 0.58 ppm. Soils on-site are contaminated with cyanide and fluoride; total cyanide levels range from ND to 985 ppm. The site is considered to be of potential public health concern because of the risk to human health caused by the possibility of exposure to hazardous substances via ingestion of contaminated ground water, dermal absorptionmore » of contaminants found in the surface soils on-site, and inhalation of and dermal contact with reentrained contaminated dust.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perona, Ralph; Whicker, Jeffrey Jay; Mirenda, Richard J.

This report documents the calculation of Authorized Limits for radionuclides in soil to be used in the transfer of property by the Los Alamos National Laboratory (LANL). The Authorized Limits support the evaluation process to clear land for release under different uses even though the soil contains small residual amounts of radioactivity. The Authorized Limits are developed for four exposure scenarios: residential, commercial/industrial, construction worker, and recreational. Exposure to radionuclides in soil under these scenarios is assessed for exposure routes that include incidental ingestion of soil; inhalation of soil particulates; ingestion of homegrown produce (residential only); and external irradiation frommore » soil. Inhalation and dermal absorption of tritiated water vapor in air are also assessed.« less

Exposure of hairdressers to the main cosmetics used in hairdressing salons in France: A preliminary study.

PubMed

Ramirez-Martinez, A; Granda-Torres, P; Wesolek, N; Ficheux, A S; Roudot, A C

2016-09-02

In recent years, more attention has been given to chemical exposure in hairdressers. This increasing interest is largely due to the various respiratory and skin symptoms observed in hairdressers. According to these symptoms, hairdressers are in contact with various sources of exposure. Particularly in France, little information is available to assess professional exposure of hairdressers. In order to gather information to assess exposure in hairdressers, 11 hairdressing salons were visited. All the salons were located in Brest City (France). Preferentially, small hairdressing salons were visited. Observations were performed to obtain salon characteristics and to record workers' practices. Calculations revealed that in the worst-case scenario, dermal professional exposure reaches 14.68 and 13.67 mg/kg/day for hair coloring and highlighting mixtures, respectively. Inhalation exposure represents 14.2 and 18.1 mg/kg/day for hair coloring and highlighting mixtures, respectively. These exposure values represent baseline values for exposure of French hairdressers working in small hairdressing salons.

The Adverse Cardiac Effects of Di(2-ethylhexyl) phthalate and Bisphenol A

PubMed Central

Posnack, Nikki Gillum

2014-01-01

The ubiquitous nature of plastics has raised concerns pertaining to continuous exposure to plastic polymers and human health risks. Of particular concern is the use of endocrine-disrupting chemicals (EDCs) in plastic production, including Di(2-ethylhexyl) phthalate (DEHP) and Bisphenol A (BPA). Widespread and continuous exposure to DEHP and BPA occurs through dietary intake, inhalation, dermal and intravenous exposure via consumer products and medical devices. This article reviews the literature examining the relationship between DEHP and BPA exposure and cardiac toxicity. In vitro and in vivo experimental reports are outlined, as well as epidemiological studies which examine the association between these chemicals and cardiovascular outcomes. Gaps in our current knowledge are also discussed, along with future investigative endeavors that may help resolve whether DEHP and/or BPA exposure has a negative impact on cardiovascular physiology. PMID:24811950

Bioavailability of organic solvents in soils: Input into biologically based dose-response models for human risk assessments. 1998 annual progress report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wester, R.C.; Maibach, H.I.

1998-06-01

'The purpose of this study is to determine the bioavailability of organic solvents following dermal exposures to contaminated soil and water. Breath analysis is being used to obtain real-time measurements of volatile organics in expired air following exposure in rats and humans. Rhesus monkeys will be used as surrogates for humans in benzene exposures. The exhaled breath data is being analyzed using physiologically based pharmacokinetic (PBPK) models to determine the dermal bioavailability of organic solvents under realistic exposure conditions. The end product of this research will be a tested framework for the rapid screening of real and potential exposures whilemore » simultaneously developing physiologically based pharmacokinetic (PBPK) models to comprehensively evaluate and compare exposures to organics from either contaminated soil or water. This report summarizes work 7 months into a 3-year project. Method development has produced systems for solvent exposure from soil and water which mimic actual exposure, and for which animals and human volunteers can be safely tested. Soil exposure is generally open to the air (working the soil) while water exposure is generally immersion. For 6--8 hour test exposure, a patch has been developed where soil is contained against the skin by a non-occlusive membrane, while simultaneously allowing volatilization of test solvent to the environment (activated charcoal). The water counterpart is an occlusive glass culture dish, sealed to skin with silicone adhesive. Shorter term exposure is done by one hand immersion in a bucket containing circulating water or soil, the volunteer instructed to move fingers through the water or soil. Human volunteers and animals breathe fresh air via a new breath-inlet system that allows for continuous real-time analysis of undiluted exhaled air. The air supply system is self-contained and separated from the exposure solvent-laden environment. The system uses a Teledyne 3DQ Discovery ion trap mass spectrometer (MS/MS) equipped with an atmospheric sampling glow discharge ionization source (ASGDI). The MS/MS system provides an appraisal of individual chemical components in the breath stream in the single-digit parts-per-billion (ppb) detectable range for each of the compounds proposed for study, while maintaining linearity of response over a wide dynamic range.'« less

EPA's SHEDS-multimedia model: children's cumulative pyrethroid exposure estimates and evaluation against NHANES biomarker data.

PubMed

Xue, Jianping; Zartarian, Valerie; Tornero-Velez, Rogelio; Tulve, Nicolle S

2014-12-01

The U.S. EPA's SHEDS-Multimedia model was applied to enhance the understanding of children's exposures and doses to multiple pyrethroid pesticides, including major contributing chemicals and pathways. This paper presents combined dietary and residential exposure estimates and cumulative doses for seven commonly used pyrethroids, and comparisons of model evaluation results with NHANES biomarker data for 3-PBA and DCCA metabolites. Model input distributions were fit to publicly available pesticide usage survey data, NHANES, and other studies, then SHEDS-Multimedia was applied to estimate total pyrethroid exposures and doses for 3-5 year olds for one year variability simulations. For dose estimations we used a pharmacokinetic model and two approaches for simulating dermal absorption. SHEDS-Multimedia predictions compared well to NHANES biomarker data: ratios of 3-PBA observed data to SHEDS-Multimedia modeled results were 0.88, 0.51, 0.54 and 1.02 for mean, median, 95th, and 99th percentiles, respectively; for DCCA, the ratios were 0.82, 0.53, 0.56, and 0.94. Modeled time-averaged cumulative absorbed dose of the seven pyrethroids was 3.1 nmol/day (versus 8.4 nmol/day for adults) in the general population (residential pyrethroid use and non-use homes) and 6.7 nmol/day (versus 10.5 nmol/day for adults) in the simulated residential pyrethroid use population. For the general population, contributions to modeled cumulative dose by chemical were permethrin (60%), cypermethrin (22%), and cyfluthrin (16%); for residential use homes, contributions were cypermethrin (49%), permethrin (29%), and cyfluthrin (17%). The primary exposure route for 3-5 year olds in the simulated residential use population was non-dietary ingestion exposure; whereas for the simulated general population, dietary exposure was the primary exposure route. Below the 95th percentile, the major exposure pathway was dietary for the general population; non-dietary ingestion was the major pathway starting below the 70th percentile for the residential use population. The new dermal absorption methodology considering surface loading had some impact, but did not change the order of key pathways. Published by Elsevier Ltd.

Cholinesterase activity in black-crowned night-herons exposed to fenthion-treated water

USGS Publications Warehouse

Smith, G.J.; Spann, J.W.; Hill, E.F.

1986-01-01

Fenthion, (O,O-Dimethyl O-(3-methyl-4-(methylthio)phenyl) phosphorothioate), a widely used mosquito control agent, has caused wildlife mortality. To simulate a shallow wetland environment, an exposure chamber was used containing water treated with fenthion at 1 and 10 times the field application rate of 112 g active ingredient (AI)/ha. This system permitted an evaluation of exposure routes and the effects of fenthion in a representative species of wading bird, the black-crowned night-heron (Nycticorax nycticorax). The results suggested that herons received only a dermal exposure, and that their brain acetylcholinesterase activity was not significantly inhibited. In contrast, however, plasma butyrylcholinesterase activity was inhibited, suggesting the herons were exposed to the insecticide. The application rates and types of exposures were not life-threatening in this species.

The chromene sargachromanol E inhibits ultraviolet A-induced ageing of skin in human dermal fibroblasts.

PubMed

Kim, J-A; Ahn, B-N; Kong, C-S; Kim, S-K

2013-05-01

Skin ageing is influenced by environmental factors such as ultraviolet (UV) radiation. The effects of UV radiation on skin functions should be investigated using human in vitro models to understand the mechanisms of skin ageing. Additionally, marine algae provide a valuable source for identifying and extracting biologically active substances. In this study, sargachromanol E was isolated from a marine brown alga, Sargassum horneri, and its inhibitory effect on skin ageing was investigated using UVA-irradiated dermal fibroblasts. Formation of intracellular reactive oxygen species (ROS), lipid peroxidation and protein oxidation induced by UVA irradiation were investigated in UVA-irradiated human dermal fibroblasts. The levels of matrix metalloproteinases (MMPs) were determined by reverse-transcriptase polymerase chain reaction and Western blot analysis. Sargachromanol E did not exhibit any significant cytotoxicity or phototoxicity in UVA-exposed dermal fibroblasts. Additionally, sargachromanol E suppressed intracellular formation of ROS, membrane protein oxidation, lipid peroxidation and expression of collagenases such as MMP-1, MMP-2 and MMP-9, all of which are caused by UVA exposure. It was further found that these inhibitions were related to an increase in the expression of the tissue inhibitor of metalloproteinase (TIMP) genes, TIMP1 and TIMP2. Moreover, we have shown that the transcriptional activation of activator protein 1 (AP-1) signalling caused by UVA irradiation was inhibited by treatment with sargachromanol E. This study suggests that UVA irradiation modulates MMP expression via the transcriptional activation of AP-1 signalling, whereas treatment with sargachromanol E protected cell damage caused by UVA irradiation. © 2013 The Authors. BJD © 2013 British Association of Dermatologists.

Health assessment for Colbert Landfill NPL (National Priorities List) Site, Spokane, Washington, Region 10. CERCLIS No. WAD980514541. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1988-07-25

The Colbert Landfill NPL site is located about fifteen miles north of Spokane, Washington. Area ground water is contaminated with several volatile organic chemicals. The medium of most concern regarding potential health effects is the ground water. Potential exposure pathways include ingestion and inhalation of volatiles from contaminated ground water and dermal exposure to contaminated ground water. The susceptible populations are remedial workers performing well water sampling on-site and populations off-site utilizing contaminated wells at levels that are of a potential health concern, for drinking, bathing, and irrigation purposes.

[Cutaneous radiation syndrome after accidental skin exposure to ionizing radiation].

PubMed

Peter, R U

2013-12-01

Accidental exposure of the human skin to single doses of ionizing radiation greater than 3 Gy results in a distinct clinical picture, which is characterized by a transient and faint erythema after a few hours, then followed by severe erythema, blistering and necrosis. Depending on severity of damage, the latter generally occurs 10-30 days after exposure, but in severe cases may appear within 48 hrs. Between three and 24 months after exposure, epidermal atrophy combined with progressive dermal and subcutaneous fibrosis is the predominant clinical feature. Even years and decades after exposure, atrophy of epidermis, sweat and sebaceous glands; telangiectases; and dermal and subcutaneous fibrosis may be found and even continue to progress. For this distinct pattern of deterministic effects following cutaneous accidental radiation exposure the term "cutaneous radiation syndrome (CRS)" was coined in 1993 and has been accepted by all international authorities including IAEA and WHO since 2000. In contrast to the classical concept that inhibition of epidermal stem cell proliferation accounts for the clinical symptomatology, research of the last three decades has demonstrated the additional crucial role of inflammatory processes in the etiology of both acute and chronic sequelae of the CRS. Therefore, therapeutic approaches should include topical and systemic anti-inflammatory measures at the earliest conceivable point, and should be maintained throughout the acute and subacute stages, as this reduces the need for surgical intervention, once necrosis has occurred. If surgical intervention is planned, it should be executed with a conservative approach; no safety margins are needed. Antifibrotic measures in the chronic stage should address the chronic inflammatory nature of this process, in which over-expression TGF beta-1 may be a target for therapeutic intervention. Life-long follow-up often is required for management of delayed effects and for early detection of secondary malignancies, which must be searched for especially in the borderline areas between clinically symptomatic and asymptomatic skin.

The hair dyes PPD and PTD fail to induce a T(H)2 immune response following repeated topical application in BALB/c mice.

PubMed

Rothe, Helga; Sarlo, Katherine; Scheffler, Heike; Goebel, Carsten

2011-01-01

1,4-Phenylenediamine (PPD) and the structurally-related 1,4-toluenediamine (PTD) are frequently used oxidative hair dye precursors that can induce a delayed-type hypersensitivity reaction known as contact allergy. Very rare cases of Type 1 (IgE-mediated) allergic responses associated with PPD or PTD have been reported among hair dye users. As part of an effort to determine if repeated dermal exposure to the dyes could induce a T-helper-2 (T(H)2) response, we used a dermal exposure regimen in mice reported to identify a T(H)2 response. Ear swelling was evident at post-final exposure to PPD and PTD, indicating that an immune response was observed. However, cytokine mRNA after repeated topical exposure to these two chemicals showed no shift in the expression toward the typical T(H)2 cytokines interleukin (IL)-4 and IL-10 compared to the T(H)1 cytokine interferon (IFN)-γ. Consistent with these cytokine profiles, no concomitant increase in total serum IgE antibody titer or in B220+IgE+ lymphocytes in lymph nodes and skin application site skin was detected. In contrast, using an identical exposure regimen, animals topically exposed to the known respiratory (Type 1) allergen toluene 2,4-diisocyanate (TDI) showed significant expression of IL-4 and IL-10 mRNA compared to IFN? as well as an increase in total serum IgE and in B220+IgE+ cells in lymph nodes and skin application site. The data generated are consistent with the pattern of adverse reactions to hair dyes seen clinically, which overwhelmingly is of delayed rather than immediate-type hypersensitivity. Although current animal models have a limited ability to detect rare T(H)2 responses to contact allergens, the present study results support the view that exposure to hair dyes is not associated with relevant T(H)2 induction.

The skin: its structure and response to ionizing radiation.

PubMed

Hopewell, J W

1990-04-01

The response of the skin to ionizing radiation has important implications both for the treatment of malignant disease by radiation and for radiological protection. The structural organization of human skin is described and compared with that of the pig, with which it shows many similarities, in order that the response of the skin to ionizing radiation may be more fully understood. Acute radiation damage to the skin is primarily a consequence of changes in the epidermis; the timing of the peak of the reaction is related to the kinetic organization of this layer. The rate of development of damage is independent of the radiation dose, since this is related to the natural rate of loss of cells from the basal layer of the epidermis. Recovery of the epidermis occurs as a result of the proliferation of surviving clonogenic basal cells from within the irradiated area. The presence of clonogenic cells in the canal of the hair follicle is important, particularly after non-uniform irradiation from intermediate energy beta-emitters. The migration of viable cells from the edges of the irradiated site is also significant when small areas of skin are irradiated. Late damage to the skin is primarily a function of radiation effects on the vasculature; this produces a wave of dermal atrophy after 16-26 weeks. Dermal necrosis develops at this time after high doses. A second phase of dermal thinning is seen to develop after greater than 52 weeks, and this later phase of damage is associated with the appearance of telangiectasia. Highly localized irradiation of the skin, either to a specific layer (as may result from exposure to very low energy beta-emitters) or after exposure to small highly radioactive particles, 'hot particles', produces gross effects that become visibly manifest within 2 weeks of exposure. These changes result from the direct killing of the cells of the skin in interphase after doses greater than 100 Gy. Dose-effect curves have been established for the majority of these deterministic endpoints in the skin from the results of both experimental and clinical studies. These are of value in the establishment of safe radiation dose limits for the skin.

Effect of mitomycin on normal dermal fibroblast and HaCat cell: an in vitro study

PubMed Central

Wang, Yao-wen; Ren, Ji-hao; Xia, Kun; Wang, Shu-hui; Yin, Tuan-fang; Xie, Ding-hua; Li, Li-hua

2012-01-01

Objective: To evaluate the effects of mitomycin on the growth of human dermal fibroblast and immortalized human keratinocyte line (HaCat cell), particularly the effect of mitomycin on intracellular messenger RNA (mRNA) synthesis of collagen and growth factors of fibroblast. Methods: The normal dermal fibroblast and HaCat cell were cultured in vitro. Cell cultures were exposed to 0.4 and 0.04 mg/ml of mitomycin solution, and serum-free culture medium was used as control. The cellular morphology change, growth characteristics, cell proliferation, and apoptosis were observed at different intervals. For the fibroblasts, the mRNA expression changes of transforming growth factor (TGF)-β1, basic fibroblast growth factor (bFGF), procollagen I, and III were detected by reverse transcription polymerase chain reaction (RT-PCR). Results: The cultured normal human skin fibroblast and HaCat cell grew exponentially. A 5-min exposure to mitomycin at either 0.4 or 0.04 mg/ml caused marked dose-dependent cell proliferation inhibition on both fibroblasts and HaCat cells. Cell morphology changed, cell density decreased, and the growth curves were without an exponential phase. The fibroblast proliferated on the 5th day after the 5-min exposure of mitomycin at 0.04 mg/ml. Meanwhile, 5-min application of mitomycin at either 0.04 or 0.4 mg/ml induced fibroblast apoptosis but not necrosis. The apoptosis rate of the fibroblast increased with a higher concentration of mytomycin (p<0.05). A 5-min exposure to mitomycin at 0.4 mg/ml resulted in a marked decrease in the mRNA production of TGF-β1, procollagen I and III, and a marked increase in the mRNA production of bFGF. Conclusions: Mitomycin can inhibit fibroblast proliferation, induce fibroblast apoptosis, and regulate intracellular protein expression on mRNA levels. In additon, mitomycin can inhibit HaCat cell proliferation, so epithelial cell needs more protecting to avoid mitomycin’s side effect when it is applied clinically. PMID:23225855

RASopathic comedo-like or cystic lesions induced by Vemurafenib: A model of skin lesions similar but not identical to those induced by dioxins (MADISH).

PubMed

Kaya, G; Saxer-Sekulic, N; Kaya, A; Sorg, O; Boespflug, A; Thomas, L; Saurat, J H

2018-03-24

Patients treated with vemurafenib for metastatic melanoma often develop skin lesions similar to those observed after exposure to dioxin-like compounds. We previously called these lesions MADISH (metabolizing acquired dioxin-induced skin hamartoma) when analysing a case of acute dioxin poisoning. We performed a clinical trial aimed at comparing the skin lesions observed under vemurafenib treatment with MADISH in order to bring to light a possible cross-talk between vemurafenib and dioxin pathways. In this case-series study we explored the histological aspect of skin lesions in 10 cases treated with vemurafenib for malignant melanoma. We also analysed the ability of vemurafenib and tyrosine kinase inhibitors to induce dioxin-AhR pathway. All patients had skin lesions diagnosed as "non-inflammatory acneiform eruption" by dermatologists. These were predominantly facial with notable retro-auricular involvement and clinically compatible with chloracne/MADISH when assessed by dioxin expert. Histological analysis showed mostly comedo-like lesions and dermal cysts containing epithelial wall with basal or lateral epithelial projections and lamellar keratinization, and alterations of remaining sebaceous glands. The expression of CYP1A1, a gene highly induced following dioxin exposure, was not observed in these lesions. Vemurafenib and the tyrosine kinase inhibitors erlotinib and gefitinib did not induce CYP1A1 activity. Although the skin lesions under vemurafenib treatment were morphologically similar to MADISH, the absence of CYP1A1 expression in dermal cysts of patients and the absence of CYP1A1 activation by vemurafenib led us consider that these skin lesions were different from true MADISH and not mediated by a cross-talk of AhR signalling, but rather to a hyperactivation of PI3K-Akt pathway as a consequence of vemurafenib treatment. A strong expression of CYP1A1 in the epithelial wall of dermal cysts must be required, parallel to the morphology of the lesions, to make the diagnosis of MADISH, the hallmark of an exposure to dioxin-like/chloracnegen compounds. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Establishment of dermal sheath cell line from Cashmere goat and characterizing cytokeratin 13 as its novel biomarker.

PubMed

Zhu, Bing; Guo, Zhili; Jin, Muzi; Bai, Yujuan; Yang, Wenliang; Hui, Lihua

2018-05-01

To establish a dermal sheath cell line, a dermal papilla cell line and a outer root sheath cell line from Cashmere goat and clarify the similarities and differences among them. We established a dermal sheath cell line, a dermal papilla cell line and a outer root sheath cell line from the pelage skin hair follicles of Cashmere goat. The growth rate of dermal sheath cells was intermediate between that of dermal papilla cells and outer root sheath cells. Immunofluorescence experiments and reverse transcription-polymerase chain reaction analysis showed that at both the transcriptional and translational levels, the dermal sheath cells were alpha-smooth muscle actin (α-SMA) + /cytokeratin 13 + , while the dermal papilla cells were α-SMA + /cytokeratin 13 - and the outer root sheath cells were α-SMA - /cytokeratin 13 + . Patterns of cytokeratin 13 expression could distinguish the dermal sheath cells from the dermal papilla cells. These results suggest that cytokeratin 13 could serve as a novel biomarker for dermal sheath cells of Cashmere goat, and should prove useful for researchers investigating dermal stem cells or interaction of different types of cells during hair cycle.

Chronic Arsenic Exposure and Risk of Post Kala-azar Dermal Leishmaniasis Development in India: A Retrospective Cohort Study

PubMed Central

Das, Sushmita; Mandal, Rakesh; Rabidas, Vidya Nand; Verma, Neena; Pandey, Krishna; Ghosh, Ashok Kumar; Kesari, Sreekant; Kumar, Ashish; Purkait, Bidyut; Lal, Chandra Sekhar; Das, Pradeep

2016-01-01

Background Visceral leishmaniasis (VL), with the squeal of Post-kala-azar dermal leishmaniasis (PKDL), is a global threat for health. Studies have shown sodium stibogluconate (SSG) resistance in VL patients with chronic arsenic exposure. Here, we assessed the association between arsenic exposure and risk of developing PKDL in treated VL patients. Methods In this retrospective study, PKDL patients (n = 139), earlier treated with SSG or any other drug during VL, were selected from the study cohort. Trained physicians, unaware of arsenic exposure, interviewed them and collected relevant data in a questionnaire format. All probable water sources were identified around the patient’s house and water was collected for evaluation of arsenic concentration. A GIS-based village-level digital database of PKDL cases and arsenic concentration in groundwater was developed and individual point location of PKDL cases were overlaid on an integrated GIS map. We used multivariate logistic regression analysis to assess odds ratios (ORs) for association between arsenic exposure and PKDL development. Results Out of the 429 water samples tested, 403 had arsenic content of over 10 μg/L, with highest level of 432 μg/L among the seven study villages. Multivariate adjusted ORs for risk of PKDL development in comparison of arsenic concentrations of 10.1–200 μg/L and 200.1–432.0 μg/L were 1.85 (1.13–3.03) and 2.31 (1.39–3.8) respectively. Interestingly, similar results were found for daily dose of arsenic and total arsenic concentration in urine sample of the individual. The multivariate-adjusted OR for comparison of high baseline arsenic exposure to low baseline arsenic exposure of the individuals in the study cohort was 1.66 (95% CI 1.02–2.7; p = 0.04). Conclusion Our findings indicate the need to consider environmental factors, like long time arsenic exposure, as an additional influence on treated VL patients towards risk of PKDL development in Bihar. PMID:27776123

Apigenin prevents ultraviolet-B radiation induced cyclobutane pyrimidine dimers formation in human dermal fibroblasts.

PubMed

Britto, S Mary; Shanthakumari, D; Agilan, B; Radhiga, T; Kanimozhi, G; Prasad, N Rajendra

2017-09-01

Exposure to solar ultraviolet-B (UVB) radiation leads to the formation of cyclobutane pyrimidine dimers (CPDs). We investigated the protective effect of apigenin against UVB-induced CPDs formation in human dermal fibroblasts cells (HDFa). For this purpose, HDFa cells were treated with apigenin (15μM) prior to UVB irradiation (20mJ/cm 2 ); DNA damage and subsequent molecular end points were observed. Exposure to UVB radiation increased significant CPDs formation in HDFa cells and the frequencies of CPDs were reduced by treatment with apigenin (15μM). UVB-induced CPDs downregulates the expression of nucleotide excision repair (NER) genes such as xeroderma pigmentosum complementation group C, B, G and F (XPC, XPB, XPG and XPF), transcription factor II human (TFIIH) and excision repair cross-complementation group 1 (ERCC1) in HDFa cells. Conversely, apigenin treatment restored UVB-induced loss of NER proteins in HDFa cells, which indicates its preventive effect against CPDs formation. Besides, single low dose UVB-exposure induced nuclear fragmentation, apoptotic frequency and apoptotic proteins expression (Bax and Caspase-3) have been prevented by the apigenin pretreatment. Furthermore, apigenin exhibits strong UV absorbance property and showed 10.08 SPF value. Thus, apigenin can protect skin cells against UVB-induced CPDs formation probably through its sunscreen effect. Hence, apigenin can be considered as an effective protective agent against UV induced skin damages. Copyright © 2017 Elsevier B.V. All rights reserved.

[Long-term complications of sulfur mustard exposure: a therapeutic update].

PubMed

Shiyovich, Arthur; Rosman, Yossi; Krivoy, Amir; Statlender, Liran; Kassirer, Michael; Shrot, Shai

2014-01-01

Sulfur mustard (SM) is an alkylating chemical warfare agent with high military significance due to its high toxicity, resistance and availability. SM was widely used in military conflicts, the last being the Iran-Iraq war with more than 100,000 Iranians exposed, one-third of whom are still suffering from late effects. The intensity of the delayed complications correlates to the extent, the area and the route of exposure. The clinical manifestations most commonly involve respiratory, ocular and dermal effects. Respiratory complications include dyspnea, cough and expectorations and various obstructive and restrictive lung diseases. Dermal complications are itching, burning sensation, blisters, dry skin, dermatitis and pigmentary changes. Ocular complications include photophobia, red eye, tearing, corneal ulcers and blindness. Although the picture remains incomplete the major mechanisms responsible for the clinical and pathological effects of SM are: DNA alkylation and cross-linking, protein modification and membrane damage in addition to induction of inflammatory mediators in the target tissues causing extensive necrosis, apoptosis and loss of tissue structure. The current report reviews long-term complications of SM exposure, focusing on new treatments tested in clinical trials conducted on humans. Such treatments include: N-acetyl cysteine, bronchodilators, corticosteroids, Interferon-gamma, furosemide and morphine for the respiratory complications. Ocular complications may entail: Invasive procedures treating corneal complication, limbal ischemia and stem cell deficiency. Treatment for dermatological complications include: anti-depressants, pimercrolimus, Unna's boot, capsaicin, phenol and menthol, Aloe vera and olive oil, curcumin and Interferon-gamma.

Gene Expression Profiling of the Intact Dermal Sheath Cup of Human Hair Follicles.

PubMed

Niiyama, Shiro; Ishimatsu-Tsuji, Yumiko; Nakazawa, Yosuke; Yoshida, Yuzo; Soma, Tsutomu; Ideta, Ritsuro; Mukai, Hideki; Kishimoto, Jiro

2018-04-24

Cells that constitute the dermal papillae of hair follicles might be derived from the dermal sheath, the peribulbar component of which is the dermal sheath cup. The dermal sheath cup is thought to include the progenitor cells of the dermal papillae and possesses hair inductive potential; however, it has not yet been well characterized. This study investigated the gene expression profile of the intact dermal sheath cup, and identified dermal sheath cup signature genes, including extracellular matrix components and BMP-binding molecules, as well as TGF-b1 as an upstream regulator. Among these, GREM2, a member of the BMP antagonists, was found by in situ hybridization to be highly specific to the dermal sheath cup, implying that GREM2 is a key molecule contributing to maintenance of the properties of the dermal sheath cup.

Dermis, acellular dermal matrix, and fibroblasts from different layers of pig skin exhibit different profibrotic characteristics: evidence from in vivo study

PubMed Central

Zuo, Yanhai; Lu, Shuliang

2017-01-01

To explore the profibrotic characteristics of the autografted dermis, acellular dermal matrix, and dermal fibroblasts from superficial/deep layers of pig skin, 93 wounds were established on the dorsa of 7 pigs. 72 wounds autografted with the superficial/deep dermis and acellular dermal matrix served as the superficial/deep dermis and acellular dermal matrix group, respectively, and were sampled at 2, 4, and 8 weeks post-wounding. 21 wounds autografted with/without superficial/deep dermal fibroblasts served as the superficial/deep dermal fibroblast group and the control group, respectively, and were sampled at 2 weeks post-wounding. The hematoxylin and eosin staining showed that the wounded skin thicknesses in the deep dermis group (superficial acellular dermal matrix group) were significantly greater than those in the superficial dermis group (deep acellular dermal matrix group) at each time point, the thickness of the cutting plane in the deep dermal fibroblast group was significantly greater than that in the superficial dermal fibroblast group and the control group. The western blots showed that the α-smooth muscle actin expression in the deep dermis group (superficial acellular dermal matrix group) was significantly greater than that in the superficial dermis group (deep acellular dermal matrix group) at each time point. In summary, the deep dermis and dermal fibroblasts exhibited more profibrotic characteristics than the superficial ones, on the contrary, the deep acellular dermal matrix exhibited less profibrotic characteristics than the superficial one. PMID:28423561

Possible endocrine disrupting effects of parabens and their metabolites.

PubMed

Boberg, Julie; Taxvig, Camilla; Christiansen, Sofie; Hass, Ulla

2010-09-01

Parabens are preservatives used in a wide range of cosmetic products, including products for children, and some are permitted in foods. However, there is concern for endocrine disrupting effects. This paper critically discusses the conclusions of recent reviews and original research papers and provides an overview of studies on toxicokinetics. After dermal uptake, parabens are hydrolyzed and conjugated and excreted in urine. Despite high total dermal uptake of paraben and metabolites, little intact paraben can be recovered in blood and urine. Paraben metabolites may play a role in the endocrine disruption seen in experimental animals and studies are needed to determine human levels of parabens and metabolites. Overall, the estrogenic burden of parabens and their metabolites in blood may exceed the action of endogenous estradiol in childhood and the safety margin for propylparaben is very low when comparing worst-case exposure to NOAELs from experimental studies in rats and mice. Copyright 2010 Elsevier Inc. All rights reserved.

Bioaccessibility of metals in alloys: Evaluation of three surrogate biofluids

PubMed Central

Hillwalker, Wendy E.; Anderson, Kim A.

2014-01-01

Bioaccessibility in vitro tests measure the solubility of materials in surrogate biofluids. However, the lack of uniform methods and the effects of variable test parameters on material solubility limit interpretation. One aim of this study was to measure and compare bioaccessibility of selected economically important alloys and metals in surrogate physiologically based biofluids representing oral, inhalation and dermal exposures. A second aim was to experimentally test different biofluid formulations and residence times in vitro. A third aim was evaluation of dissolution behavior of alloys with in vitro lung and dermal biofluid surrogates. This study evaluated the bioaccessibility of sixteen elements in six alloys and 3 elemental/metal powders. We found that the alloys/metals, the chemical properties of the surrogate fluid, and residence time all had major impacts on metal solubility. The large variability of bioaccessibility indicates the relevancy of assessing alloys as toxicologically distinct relative to individual metals. PMID:24212234

Chronic UVB-irradiation actuates perpetuated dermal matrix remodeling in female mice: Protective role of estrogen

PubMed Central

Röck, Katharina; Joosse, Simon Andreas; Müller, Julia; Heinisch, Nina; Fuchs, Nicola; Meusch, Michael; Zipper, Petra; Reifenberger, Julia; Pantel, Klaus; Fischer, Jens Walter

2016-01-01

Chronic UVB-exposure and declined estradiol production after menopause represent important factors leading to extrinsic and intrinsic aging, respectively. Remodeling of the extracellular matrix (ECM) plays a crucial role in both responses. Whether the dermal ECM is able to recover after cessation of UVB-irradiation in dependence of estradiol is not known, however of relevance when regarding possible treatment options. Therefore, the endogenous sex hormone production was depleted by ovariectomy in female mice. Half of the mice received estradiol substitution. Mice were UVB-irradiated for 20 weeks and afterwards kept for 10 weeks without irradiation. The collagen-, hyaluronan- and proteoglycan- (versican, biglycan, lumican) matrix, collagen cleavage products and functional skin parameters were analyzed. The intrinsic aging process was characterized by increased collagen fragmentation and accumulation of biglycan. Chronic UVB-irradiation additionally augmented the lumican, versican and hyaluronan content of the dermis. In the absence of further UVB-irradiation the degradation of collagen and accumulation of biglycan in the extrinsically aged group was perpetuated in an excessive matter. Whereas estradiol increased the proteoglycan content, it reversed the effects of the perpetuated extrinsic response on collagen degradation. Suspension of the intrinsic pathway might therefore be sufficient to antagonize UVB-evoked long-term damage to the dermal ECM. PMID:27460287

Interaction of New-Developed TiO2-Based Photocatalytic Nanoparticles with Pathogenic Microorganisms and Human Dermal and Pulmonary Fibroblasts

PubMed Central

Nica, Ionela Cristina; Stan, Miruna Silvia; Popa, Marcela; Chifiriuc, Mariana Carmen; Lazar, Veronica; Pircalabioru, Gratiela G.; Dumitrescu, Iuliana; Ignat, Madalina; Feder, Marcel; Tanase, Liviu Cristian; Mercioniu, Ionel; Diamandescu, Lucian; Dinischiotu, Anca

2017-01-01

TiO2-based photocatalysts were obtained during previous years in order to limit pollution and to ease human daily living conditions due to their special properties. However, obtaining biocompatible photocatalysts is still a key problem, and the mechanism of their toxicity recently received increased attention. Two types of TiO2 nanoparticles co-doped with 1% of iron and nitrogen (TiO2-1% Fe–N) atoms were synthesized in hydrothermal conditions at pH of 8.5 (HT1) and 5.5 (HT2), and their antimicrobial activity and cytotoxic effects exerted on human pulmonary and dermal fibroblasts were assessed. These particles exhibited significant microbicidal and anti-biofilm activity, suggesting their potential application for microbial decontamination of different environments. In addition, our results demonstrated the biocompatibility of TiO2-1% Fe–N nanoparticles at low doses on lung and dermal cells, which may initiate oxidative stress through dose accumulation. Although no significant changes were observed between the two tested photocatalysts, the biological response was cell type specific and time- and dose-dependent; the lung cells proved to be more sensitive to nanoparticle exposure. Taken together, these experimental data provide useful information for future photocatalytic applications in the industrial, food, pharmaceutical, and medical fields. PMID:28125053

Child-Specific Exposure Factors Handbook (Final Report) ...

EPA Pesticide Factsheets

The National Center for Environmental Assessment Staff (NCEA) have prepared this handbook to provide information on various physiological and behavioral factors commonly used in assessing children’s exposure to environmental chemicals. Children have different exposure circumstances than do adults. Understanding these differences is key for evaluating potential for environmental hazards from pollutants. They consume more of certain foods and water and have higher inhalation rates per unit of body weight than adults. Young children play close to the ground and come into contact with contaminated soil outdoors and with contaminated dust on surfaces and carpets indoors. Ingestion of human milk may be another potential pathway of exposure for infants and young children. The Child-Specific Exposure Factors Handbook provides a summary of statistical data on various exposure factors used in assessing children exposures. These factors include: drinking water consumption; soil ingestion and mouthing behavior; inhalation rates; dermal factors including skin surface area and soil adherence factors; consumption of retail and home-grown foods; breast milk intake; body weight; and activity pattern data.

Organophosphate pesticide method development and presence of chlorpyrifos in the feet of nearctic-neotropical migratory songbirds from Canada that over-winter in Central America agricultural areas.

PubMed

Alharbi, Hattan A; Letcher, Robert J; Mineau, Pierre; Chen, Da; Chu, Shaogang

2016-02-01

Recent modeling analysis suggests that numerous birds may be at risk of acute poisoning in insecticide-treated fields. Although the majority of avian field studies on pesticides have focused on treated seed, granule, insect or vegetation (oral exposure) ingestion, dermal exposure is an important exposure route when birds come into contact with deposited pesticides on foliage and other surfaces. Some nearctic-neotropical migratory songbirds are likely exposed to pesticides on their non-breeding habitats and include treated crops, plantations or farmlands. In the present study, we developed a method for four environmentally-relevant organophosphate (OP) pesticides (fenthion, fenamiphos, chlorpyrifos and diazinon) in the feet of migratory songbirds (i.e. Common yellowthroat, Gray catbird, Indigo bunting, America redstart, Northern waterthrush, Northern parula, and an additional 12 species of warblers). A total of 190 specimens of the 18 species of songbirds were sampled from available window-killed birds (spring of 2007 and 2011) in downtown Toronto, Canada. The species that were available most likely over-wintered in Mexican/Central American crops such as citrus, coffee and cacao. The feet of the dead birds were sampled and where OP foot exposure likely occurred during over-wintering foraging on pesticide-treated crops. Chlorpyrifos was the only measurable OP (pg mg feet weight(-1)) and in the 2011-collected feet of Black throated blue warbler (0.5), Tennessee warbler (1.0), Northern parula (1.2), Northern waterthrush (0.6), Common yellowthroat (1.0) and the Blue winged warbler (0.9). Dermal contact with OP pesticides during over-wintering in agricultural areas resulted in low levels of chlorpyrifos and long time retention on the feet of a subset of songbirds. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

Human health risk assessment of occupational and residential exposures to dechlorane plus in the manufacturing facility area in China and comparison with e-waste recycling site.

PubMed

Wang, De-Gao; Alaee, Mehran; Byer, Jonathan D; Brimble, Samantha; Pacepavicius, Grazina

2013-02-15

A screening level human health risk assessment based on the worst-case scenario was conducted on the occupational and residential exposures to dechlorane plus (DP) in the manufacturing facility region and an electronic-waste (e-waste) recycling site in China, which are two of the most polluted areas of DP in the world. Total estimated exposure doses (EEDs) via dietary intake, dermal contact, and inhalation was approximately 0.01 mg kg(-1) d(-1) for people living in the manufacturing facility region. In comparison, total EEDs (approximate 0.03 μg kg(-1), d(-1)) were 300-fold lower in people living near an e-waste recycling site in China. Chronic oral, dermal, and inhalation reference doses (RfDs) were estimated to be 5.0, 2.0, and 0.01 mg kg(-1)d (-1), respectively. The oral RfD was markedly greater than Mirex (2×10(-4) mg kg(-1) d(-1)) and decabromodiphenyl ether (BDE-209; 7×10(-3) mg kg(-1) d(-1)), which have been or might be replaced by DP as a flame retardant with less toxicity. Monte Carlo simulation was used to generate the probability densities and functions for the hazard index which was calculated from the EEDs and RfDs to assess the human health risk. The hazard index was three orders of magnitude lower than 1, suggesting that occupational and residential exposures were relatively safe in the manufacturing facility region and e-waste recycling site. Copyright © 2012 Elsevier B.V. All rights reserved.