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Piscataway, NJ, United States

Vallero D.,U.S. Environmental Protection Agency | Isukapalli S.,EOHSI
Journal of Exposure Science and Environmental Epidemiology | Year: 2014

A prospective personal exposure study, involving indoor and outdoor releases, was conducted in upper Midtown Manhattan in New York City as part of the Urban Dispersion Program (UDP) focusing on atmospheric dispersion of chemicals in complex urban settings. The UDP experiments involved releases of very low levels of perfluorocarbon tracers (PFTs) in Midtown Manhattan at separate locations, during two seasons in 2005. The study presented here includes both outdoor and indoor releases of the tracers, and realistic scripted activities for characterizing near source and neighborhood-scale exposures using 1-min and 10-min duration samples, respectively. Results showed that distributions of individual tracers and exposures to them within the study area were significantly influenced by surface winds, urban terrain, and movements of people typical of urban centers. Although in general, PFT levels returned quickly to zero in general after cessation of the emissions, in some cases, the concentrations stayed at higher levels after the releases stopped. This is likely due to accumulation of the PFTs in some buildings, which then serve as "secondary sources" when outside levels are lower than indoor levels. Measurements of neighborhood-scale PFT concentrations (up to distances of several blocks away from the release points) provided information needed to establish a baseline for determining how different types of releases could affect exposures both to the general public and to emergency responders. These data highlight the factors impacting the toxic threat levels following releases of hazardous chemicals and provide supporting information for evaluating and refining protocols for emergency event response.© 2014 Nature America, Inc. Source


Greenberg M.,Rutgers University | Lioy P.,EOHSI | Ozbas B.,Rutgers University | Mantell N.,Rutgers University | And 8 more authors.
Risk Analysis | Year: 2013

We built three simulation models that can assist rail transit planners and operators to evaluate high and low probability rail-centered hazard events that could lead to serious consequences for rail-centered networks and their surrounding regions. Our key objective is to provide these models to users who, through planning with these models, can prevent events or more effectively react to them. The first of the three models is an industrial systems simulation tool that closely replicates rail passenger traffic flows between New York Penn Station and Trenton, New Jersey. Second, we built and used a line source plume model to trace chemical plumes released by a slow-moving freight train that could impact rail passengers, as well as people in surrounding areas. Third, we crafted an economic simulation model that estimates the regional economic consequences of a variety of rail-related hazard events through the year 2020. Each model can work independently of the others. However, used together they help provide a coherent story about what could happen and set the stage for planning that should make rail-centered transport systems more resistant and resilient to hazard events. We highlight the limitations and opportunities presented by using these models individually or in sequence. © 2013 Society for Risk Analysis. Source


Coughlin J.L.,EOHSI | Coughlin J.L.,Rutgers University | Thomas P.E.,EOHSI | Thomas P.E.,Rutgers University | And 2 more authors.
Drug Metabolism and Disposition | Year: 2012

Genistein is a natural phytoestrogen of the soybean, and bisphenol A (BPA) is a synthetic chemical used in the production of polycarbonate plastics. Both genistein and BPA disrupt the endocrine system in vivo and in vitro. Growing concerns of altered xenobiotic metabolism due to concomitant exposures from soy milk in BPA-laden baby bottles has warranted the investigation of the glucuronidation rate of genistein in the absence and presence (25 μM) of BPA by human liver microsomes (HLM) and rat liver microsomes (RLM). HLM yield V max values of 0.93 ± 0.10 nmol · min -1 · mg -1 and 0.62 ± 0.05 nmol · min -1 · mg -1 in the absence and presence of BPA, respectively. K m values for genistein glucuronidation by HLM in the absence and presence of BPA are 15.1 ± 7.9 μM and 21.5 ±7.7 μM, respectively, resulting in a K i value of 58.7 μM for BPA. Significantly reduced V max and unchanged K m in the presence of BPA in HLM are suggestive of noncompetitive inhibition. In RLM, the presence of BPA resulted in a K i of 35.7 μM, an insignificant change in V max (2.91 ± 0.26 nmol · min -1 · mg -1 and 3.05 · 0.41 nmol · min -1 · mg -1 in the absence and presence of BPA, respectively), and an increase in apparent K m (49.4 ± 14 μM with no BPA and 84.0 ± 28 μM with BPA), indicative of competitive inhibition. These findings are significant because they suggest that BPA is capable of inhibiting the glucuronidation of genistein in vitro, and that the type of inhibition is different between HLM and RLM. Copyright © 2012 by The American Society for Pharmacology and Experimental Therapeutics. Source

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