Assessment of Inhalation Exposures and Potential Health Risks to the General Population that Resulted from the Collapse of the World Trade Center Towers

National Center for Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, 1200 Pennsylvania Ave., Washington, DC 22314, USA.
Risk Analysis (Impact Factor: 2.5). 11/2007; 27(5):1203-21. DOI: 10.1111/j.1539-6924.2007.00956.x
Source: PubMed

ABSTRACT In the days following the collapse of the World Trade Center (WTC) towers on September 11, 2001 (9/11), the U.S. Environmental Protection Agency (EPA) initiated numerous air monitoring activities to better understand the ongoing impact of emissions from that disaster. Using these data, EPA conducted an inhalation exposure and human health risk assessment to the general population. This assessment does not address exposures and potential impacts that could have occurred to rescue workers, firefighters, and other site workers, nor does it address exposures that could have occurred in the indoor environment. Contaminants evaluated include particulate matter (PM), metals, polychlorinated biphenyls, dioxins, asbestos, volatile organic compounds, particle-bound polycyclic aromatic hydrocarbons, silica, and synthetic vitreous fibers (SVFs). This evaluation yielded three principal findings. (1) Persons exposed to extremely high levels of ambient PM and its components, SVFs, and other contaminants during the collapse of the WTC towers, and for several hours afterward, were likely to be at risk for acute and potentially chronic respiratory effects. (2) Available data suggest that contaminant concentrations within and near ground zero (GZ) remained significantly elevated above background levels for a few days after 9/11. Because only limited data on these critical few days were available, exposures and potential health impacts could not be evaluated with certainty for this time period. (3) Except for inhalation exposures that may have occurred on 9/11 and a few days afterward, the ambient air concentration data suggest that persons in the general population were unlikely to suffer short-term or long-term adverse health effects caused by inhalation exposures. While this analysis by EPA evaluated the potential for health impacts based on measured air concentrations, epidemiological studies conducted by organizations other than EPA have attempted to identify actual impacts. Such studies have identified respiratory effects in worker and general populations, and developmental effects in newborns whose mothers were near GZ on 9/11 or shortly thereafter. While researchers are not able to identify specific times and even exactly which contaminants are the cause of these effects, they have nonetheless concluded that exposure to WTC contaminants (and/or maternal stress, in the case of developmental effects) resulted in these effects, and have identified the time period including 9/11 itself and the days and few weeks afterward as a period of most concern based on high concentrations of key pollutants in the air and dust.

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    • "Mathematical models suggest that because 95% of human exposure to dioxin and furans tends to occur through food consumption and only 1% by inhalation, WTC pile workers exposed to high levels of dioxin for 3 months had only an estimated 17% higher burden of these two toxins after 3 months of exposure, and modeled body burden would have returned to near background levels after leaving the area or after ambient levels dropped to background concentrations (by December 2001 in the areas near the WTC site and by May 2002 at the site) [12]. Findings from these models suggest that exposures to dioxins and furans did not significantly increase lifetime cancer risk [12] [14]. "
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    Annals of Epidemiology 07/2014; 25(5). DOI:10.1016/j.annepidem.2014.05.016 · 2.00 Impact Factor
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    • "To date, the model developed by Nicholson (1986) has been the most often used for asbestos cancer risk assessment (Azuma et al., 2009; Camus et al., 1998, 2002; Lorber et al., 2007). However , an increasing number of studies are now using Berman and Crump potency factors or developing ones based on meta-analytic techniques (Hodgson and Darnton, 2010; Lenters et al., 2011; Loomis et al., 2009). "
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    ABSTRACT: Asbestos-related cancer risk is usually a concern restricted to occupational settings. However, recent published data on asbestos environmental concentrations in Thetford Mines, a mining city in Quebec, Canada, provided an opportunity to undertake a prospective cancer risk assessment in the general population exposed to these concentrations. Using an updated Berman and Crump dose-response model for asbestos exposure, we selected population-specific potency factors for lung cancer and mesothelioma. These factors were evaluated on the basis of population-specific cancer data attributed to the studied area's past environmental levels of asbestos. We also used more recent population-specific mortality data along with the validated potency factors to generate corresponding inhalation unit risks. These unit risks were then combined with recent environmental measurements made in the mining town to calculate estimated lifetime risk of asbestos-induced lung cancer and mesothelioma. Depending on the chosen potency factors, the lifetime mortality risks varied between 0.7 and 2.6 per 100,000 for lung cancer and between 0.7 and 2.3 per 100,000 for mesothelioma. In conclusion, the estimated lifetime cancer risk for both cancers combined is close to Health Canada's threshold for "negligible" lifetime cancer risks. However, the risks estimated are subject to several uncertainties and should be confirmed by future mortality rates attributed to present day asbestos exposure.
    International journal of hygiene and environmental health 07/2013; 217(2-3). DOI:10.1016/j.ijheh.2013.07.008 · 3.83 Impact Factor
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    • "For example, MEP may represent more recent and MBP less recent exposure, and either metabolite or their sums may misclassify exposure. As discussed recently using DEHP metabolites, metabolites with longer or shorter elimination half-lives may underestimate or overestimate exposure over an interval ( " near " vs. " distant " ) (Lorber et al. 2007). Taking these factors into account, in addition to biologic potency and dilution correction (see (McLachlan 1993)), could improve risk estimates using exposure biomarkers. "
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    Environmental Research 01/2012; 112:186-93. DOI:10.1016/j.envres.2011.12.006 · 4.37 Impact Factor
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