Entity

Time filter

Source Type

Ivyland, PA, United States

Trumbore D.,Owens Corning Asphalt Technology Laboratory | Osborn L.,Heritage Research Group | Blackburn G.,PetroLabs Inc | Niebo R.,Everest Consulting Associates | And 2 more authors.
Inhalation Toxicology | Year: 2011

Recent studies have reported divergent results in rodent cancer assays using fume condensates from a variety of asphalt products. This paper presents results of a study investigating the role of oxidation, or extent of oxidation, on these findings. Five straight run asphalts, made from widely used crude oils, were used as inputs to both production scale and laboratory oxidation units and processed to a range of softening points used in common roofing products. For each of the five asphalts studied, the oxidation reaction significantly decreased measures of polycyclic aromatic compounds (PACs) that have been linked, previously and in analyses included in this study, to tumor induction in rodent bioassays. Mutagenicity index determined by the modified Ames assay was reduced between 41% and 50% from the input asphalt to the final oxidized product. A fluorescence method tuned to a subset of PAC compounds that have been associated with carcinogenic behavior in mouse bioassays was reduced between 39% and 71%. The decrease was largest in the first quarter of the oxidation reaction. These findings indicate that oxidation, by itself, was not a likely factor in the tumor induction seen in the previous studies. Rather, other factors such as the conditions of fume generation and crude source (coupled with possible differences in distillation endpoints) were more likely to have determined the outcomes. Analyses of previously published data, presented in this paper, suggest that the modified Ames and fluorescence assays are valuable screening tools for use in future health-related asphalt research. © 2011 Informa Healthcare USA, Inc. Source


Kriech A.J.,Heritage Research Group | Osborn L.V.,Heritage Research Group | Snawder J.E.,U.S. National Institute for Occupational Safety and Health | Olsen L.D.,U.S. National Institute for Occupational Safety and Health | And 4 more authors.
Polycyclic Aromatic Compounds | Year: 2011

Innovations in science may require crossing traditional boundaries between industry, unions, government, and academia. While such collaborations have the potential to be highly beneficial and productive, opportunities for such collaborations are often missed due to some of the inherent challenges. This collaborative research effort demonstrates an example of how a successful partnership can optimize the ability to answer complicated scientific questions. Specifically, these researchers collaborated to investigate inhalation and dermal exposures to polycyclic aromatic compounds and related urinary metabolites in hot-mix asphalt paving workers. Reported here are details of the partnership process used to create the study design, the review processes, and details of the analytical methodologies employed to help attain the study goals related to the identification of the nature, source, pathway, and biological relevance of exposure during hot-mix asphalt paving operations. The actual results of the study are being prepared for future publications. © Taylor & Francis Group, LLC. Source


Osborn L.V.,Heritage Research Group | Snawder J.E.,U.S. National Institute for Occupational Safety and Health | Olsen L.D.,U.S. National Institute for Occupational Safety and Health | Kriech A.J.,Heritage Research Group | And 4 more authors.
Polycyclic Aromatic Compounds | Year: 2011

As part of the design of a comprehensive study of hot-mix asphalt paving workers to investigate the relative contribution of personal breathing zone and dermal exposures to polycyclic aromatic compounds, a two-part pilot (Phase I) was performed. The pilot study was important to examine the sources of exposure, the chemical nature of these exposures, and their biological relevance through analysis of biomarkers in urine. Existing, modified, and new sampling and analytical techniques, used in concert with each other, were evaluated to help design the full-scale study (Phase II).Although subject numbers were limited, the air, dermal, and urine sampling, analytical results and field experience provided valuable guidance in the design and implementation of Phase II. An overview of methods used and developed from this study is provided. More details of those methods selected for Phase II are presented in complementary manuscripts. Results of Phase II will be the subject of future publications. © Taylor & Francis Group, LLC. Source


Osborn L.V.,Heritage Research Group | Snawder J.E.,Centers for Disease Control and Prevention | Kriech A.J.,Heritage Research Group | Cavallari J.M.,University of Connecticut Health Center | And 4 more authors.
Journal of Occupational and Environmental Hygiene | Year: 2013

An exposure assessment of hot-mix asphalt (HMA) paving workers was conducted to determine which of four exposure scenarios impacted worker exposure and dose. Goals of this report are to present the personal-breathing zone (PBZ) data, discuss the impact of substituting the releasing/cleaning agent, and discuss work practices that resulted in the highest exposure concentration for each analyte. One-hundred-seven PBZ samples were collected from HMA paving workers on days when diesel oil was used as a releasing/cleaning agent. An additional 36 PBZ samples were collected on days when B-100 (100% biodiesel, containing no petroleum-derived products) was used as a substitute releasing/cleaning agent. Twenty-four PBZ samples were collected from a reference group of concrete workers, who also worked in outdoor construction but had no exposure to asphalt emissions. Background and field blank samples were also collected daily. Total particulates and the benzene soluble fraction were determined gravimetrically. Total organic matter was determined using gas chromatography (GC) with flame ionization detection and provided qualitative information about other exposure sources contributing to worker exposure besides asphalt emissions. Thirty-three individual polycyclic aromatic compounds (PACs) were determined using GC with time-of-flight mass spectrometry; results were presented as either the concentration of an individual PAC or a summation of the individual PACs containing either 2-to 3-rings or 4-to 6-rings. Samples were also screened for PACs containing 4-to 6-rings using fluorescence spectroscopy. Arithmetic means, medians, and box plots of the PBZ data were used to evaluate trends in the data. Box plots illustrating the diesel oil results were more variable than the B-100. Also, the highest diesel oil results were much higher in concentration than the highest B-100 results. An analysis of the highest exposure results and field notes revealed a probable association between these exposures and the use of diesel oil, use of a diesel-powered screed, elevated HMA paving application temperatures, lubricating and working on broken-down equipment, and operation of a broom machine. [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 containing tables summarizing statistical data and individual analyte results. © 2013 Taylor and Francis Group, LLC. Source


Blackburn G.R.,PetroLabs Inc | Bleicher Jr. W.T.,PetroLabs Inc | Glidden S.,Mathy Technology and Engineering Services Inc. | Reinke G.,Mathy Technology and Engineering Services Inc.
Polycyclic Aromatic Compounds | Year: 2012

A laboratory fuming procedure was used in combination with a previously reported variation of the Ames Test (the Nitration Assay) to investigate the relationship between temperature, time at temperature, and distance from source, on the relative PAC content of fumes generated from paving bitumens. The test method, whose endpoint is mutagenic potency (Nitration Mutagenicity Index, NMI), takes advantage of large amplifications of Ames Test mutagenicity resulting from nitro-derivatization of PACs. NMIs were similar and quite low for fumes generated at 110°C, but increased exponentially up to 160°C. NMIs increased linearly with fuming time up to 40 min, after which they remained constant. With some initial fluctuation, they also remained constant with increasing distance of the condenser from the bitumen surface up to 100 cm. NMI increased with temperature at a faster rate than fume weight suggesting that the increases in NMI were related to both quantitative and qualitative changes in the PAC content of the fumes. © 2012 Copyright Taylor and Francis Group, LLC. Source

Discover hidden collaborations