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Robbins C.A.,Veritox Inc. | Krause M.W.,Veritox Inc. | Atallah R.H.,Veritox Inc. | Atallah R.H.,Dade Moeller and Associates Inc | Plisko M.J.,Environmental Profiles Inc.
Journal of Chemical Health and Safety

It has been reported that the presence of ≤0.1% benzene in base solvents often used for cleaning is likely to result in exposure concentrations above the current OSHA PEL. This prediction was based upon calculations that depend largely on the concentration of benzene assumed to be present in a solvent mixture. Measurements of exposure during work simulations and more comprehensive modeling studies show that many factors other than the benzene content of the bulk solvent influence personal and area vapor concentrations. This study examines benzene exposure due to trace amounts of benzene in solvents available recently, and whether exposure in excess of the OSHA benzene standard occurs when 10 and 50. mL of base solvents containing up to 0.1% benzene are used during a manual cleaning process in a poorly ventilated room.Breathing zone (BZ) concentrations were measured for benzene, toluene and xylene during repetitions of a cleaning procedure using a small cloth to wipe a metal paint tray with 10 and 50. mL of consumer-grade toluene and xylene alone and toluene spiked with 0.1% benzene. Air samples were collected in the breathing zone (BZ) for 15. min to determine the short-term exposure. Separate 2. hr samples were collected in the BZ and general area to obtain time-weighted average (TWA) exposure concentrations. All samples were analyzed with a GC-FID utilizing NIOSH Method 1501.A near field-far field (NF-FF) model was used in conjunction with Monte Carlo simulation to predict airborne benzene, toluene, and xylene concentrations and to quantify uncertainty in the input parameters of the model. Variables including solvent evaporation time and air movement around the worker during the work activity were analyzed over a range of possible values. The result after 10 5 iterations of Monte Carlo simulation was a range of possible outcomes and the likelihood that each would occur; these outcomes are compared to the measured airborne concentrations.Cleaning the metal pan with 10-50. mL of toluene or xylene with or without 0.1% benzene did not result in benzene exposures in excess of either the OSHA PEL 8-hr TWA (1.0. ppm) or action level (0.5. ppm). The ratio of predicted or modeled to measured benzene concentration ranged from 0.42 to 2.1. The ratio of predicted or modeled to measured xylene and toluene concentration ranged from 0.92 to 3.7. Application of the NF-FF model under the conditions studied indicates a reasonable degree of reliability in forecasting airborne solvent concentrations under the conditions studied. © 2012 Division of Chemical Health and Safety of the American Chemical Society. Source

Gilden R.,University of Maryland, Baltimore | Plisko M.,Environmental Profiles Inc. | Hiteshew K.,Environmental Profiles Inc. | Friedmann E.,University of Maryland, Baltimore | Milton D.,University of Maryland College Park
Environmental Research

Objective: We sought to determine the feasibility of measuring pesticide exposure of children using athletic fields to which pesticides were recently applied. Design and sample: This project was a pilot feasibility study designed to measure pre and posttest environmental exposure to Horsepower; a combination herbicide containing (4-Chloro-2-methylphenoxy) acetic acid (MCPA), dicamba and triclopyr. A spot application of Horsepower to a soccer field occurred at 8AM. Six players, ages 5-11 years, provided shoe wipes and urine samples before and after evening soccer practice on the field later the same day. Measurements and results: We sent samples to commercial labs where shoe wipes were analyzed for a panel of herbicides and urine samples were analyzed for dicamba, triclopyr, and creatinine. All analytes were below level of detection. Conclusions: We established the feasibility of both the recruitment and sampling procedures. Spot application, in the one instance examined, did not result in measurable exposure to pesticides. A larger study involving both spot and broadcast application and including direct observation of pesticide application is needed to ascertain whether pesticide application on athletic fields results in measurable and potentially hazardous exposure of children. © 2016 Elsevier Inc. Source

West G.H.,The Center for Construction Research and Training | Lippy B.E.,The Center for Construction Research and Training | Cooper M.R.,The Center for Construction Research and Training | Marsick D.,Marsick Consulting LLC | And 3 more authors.
Journal of Nanoparticle Research

The global construction sector is experiencing major improvements to building materials used in large quantities through commercial applications of nanotechnology. Nano-enabled construction products hold great promise for energy efficiency and resource conservation, but risk assessments lag as new products emerge. This paper presents results from an inventory, survey, and exposure assessment conducted by the authors and explores these findings in the broader context of evolving research trends and responsible development of nanotechnology. An inventory of 458 reportedly nano-enabled construction products provided insight into product availability, potential exposures, and deficiencies in risk communication that are barriers to adoption of proactive safety measures. Seasoned construction trainers surveyed were largely unaware of the availability of nano-enabled construction products. Exposure assessment demonstrated the effectiveness of ventilation to reduce exposures during mechanical abrasion of photocatalytic tiles containing titanium dioxide (TiO2). Dissociated particles of TiO2 just above the nanoscale (138 nm) were detected in the debris collected during cutting of the tiles, but measurements were below recommended exposure limits for TiO2. Exposure assessments remain scarce, and toxicological understanding primarily pertains to unincorporated nanomaterials; less is known about the occupational risks of nano-enabled construction products across their life cycle. Further research is needed to characterize and quantify exposure to debris released from nanocomposite materials for realistic risk assessment, and to ascertain how nanocomposite matrices, fillers, and degradation forces interact to affect release dynamics. Improving risk communication strategies and implementing safe work practices will cultivate responsible development of nanotechnology in construction, as will multidisciplinary research efforts. © 2016, Springer Science+Business Media Dordrecht. Source

Hofstetter E.,Environmental Profiles Inc. | Spencer J.W.,Environmental Profiles Inc. | Hiteshew K.,Environmental Profiles Inc. | Coutu M.,Environmental Profiles Inc. | Nealley M.,Environmental Profiles Inc.
Annals of Occupational Hygiene

Predictive modeling is an available tool to assess worker exposures to a variety of chemicals in different industries and product-use scenarios. The European Chemical Agency (ECHA)'s guidelines for manufacturers to fulfill the European Union's legal requirements pursuant to the Registration, Evaluation, Authorization, and Restriction of Chemicals (REACH) initiative include recommendations for the use of modeling to predict worker exposures. ECHA recommends different models for different target populations (i.e. workers, consumers, environment) and routes of exposure (i.e. skin absorption, ingestion, inhalation), and presents them hierarchically, with Tier 1 models presented as the most simplistic, conservative models and Tier 2 models recommended for further intensive evaluation of substances or preparations. In order to assess these models for one exposure (product-use) scenario, a simulation of the scenario was completed in a controlled environment and the measured results were compared with the modeling outputs. The authors predicted, based on the design of the modeling tools, that all models would overestimate worker exposures under the simulated product-use scenario, with the lower-tiered model producing the most conservative estimate of exposure. In this study, a Tier 1 model and a Tier 2 model were evaluated for comparison with the near-field, far-field (NF-FF) deterministic model and measured experimental results in a real-time worker inhalation exposure assessment. Modeling was conducted prior to actual air monitoring. The exposure scenario that was evaluated involved the application of a toluene-containing spray paint to a work surface. Air samples were collected to evaluate short-term (15-min) and long-term (240-min) exposures. Eight-hour time-weighted averages (8-h TWAs) were calculated and compared with the modeling outputs from the recommended REACH modeling tools and the NF-FF model. A comparison of each of the modeling tools with measured experimental results was generated. The Tier 1 Targeted Risk Assessment tool overestimated the 8-h TWA airborne concentration of toluene in the spray scenario by a factor of 3.61. The higher tiered Advanced REACH Tool and NF-FF models showed greater concordance with experimental results, overestimating the TWA exposure by a factor of 2.92 and 1.96, respectively. In conclusion, the Tier 1 and 2 exposure modeling tools performed as expected for the simulated exposure scenario, providing relatively accurate, though conservative, estimates according to the level of detail and precision accounted for in each model. © 2012 © The Author 2012. Published by Oxford University Press on behalf of the British Occupational Hygiene Society. Source

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