Date Published: February 8, 2018
Publisher: Public Library of Science
Author(s): Jennifer A. Horney, Gaston A. Casillas, Erin Baker, Kahler W. Stone, Katie R. Kirsch, Krisa Camargo, Terry L. Wade, Thomas J. McDonald, Andy T. Y. Lau.
Polycyclic aromatic hydrocarbons (PAHs) are complex environmental toxicants. Exposure to them has been linked to adverse health outcomes including cancer, as well as diseases of the skin, liver, and immune system. Based on an ongoing community engagement partnership with stakeholder groups and residents, we conducted a small longitudinal study to assess domestic exposure to PAHs among residents of Manchester, an environmental justice neighborhood located in the East End of Houston, TX.
In December, 2016, we used fiber wipes to collect samples of household dust from 25 homes in Manchester. Following Hurricane Harvey, in September 2017, we revisited 24 of the 25 homes to collect soil samples from the front yards of the same homes. Wipes and soil were analyzed for the presence of PAHs using gas chromatography–mass spectrometry (GC-MS) methods. Principal component analysis plots, heatmaps, and PAH ratios were used to compare pre- and post-Hurricane Harvey samples.
While direct comparison is not possible, we present three methods for comparing PAHs found in pre-hurricane fiber wipes and post-hurricane soil samples. The methods demonstrate that the PAHs found before and after Hurricane Harvey are likely from similar sources and that those sources are most likely to be associated with combustion. We also found evidence of redistribution of PAHs due to extreme flooding associated with Hurricane Harvey.
Residents of the Manchester neighborhood of Houston, TX, are exposed to a range of PAHs in household dust and outdoor soil. While it was not possible to compare directly, we were able to use several methods to assess detected concentrations, changes in site-specific PAH allocations, and PAH origination. Additional research is needed to identify specific sources of domestic PAH exposure in these communities and continued work involving community members and policy makers should aim to develop interventions to reduce domestic exposure to and prevent negative health outcomes from PAHs.
Over the last decade, calls to increase the quantity and improve the quality of post-disaster research have come from both the academic and applied public health communities [1–4]. Rapid and credible post-disaster research is now seen as essential for protecting the health of the public and responders, and necessary for increasing trust of governmental response agencies among affected populations . Conducting meaningful research in the context of a public health emergency requires addressing several potentially challenging gaps including: knowledge gaps presented by public health emergencies that require interdisciplinary and academic-practice collaborations to address; difficulties in planning for, and rapidly executing, scientific research in the context of disaster response; and a general lack of available baseline data to compare with post-disaster findings to determine changes that may be attributable to the disaster [3,5]. This paper offers one approach to addressing these three challenges by presenting results from a small study of pre- and post-Hurricane Harvey exposure to polycyclic aromatic hydrocarbons (PAHs) among residents of a Houston environmental justice neighborhood.
The concentration of total PAHs in each wipe sample was widely variable, ranging from 0.29 to 3.95 μg/m2. The concentration of total PAHs in each soil sample ranged from 54.65 to 4,378.25 μg/kg. From these ranges, it was observed that the PAH concentrations were very different in the wipes and soils. To further evaluate the sample types, the concentrations were log transformed then analyzed by PCA. In the PCA, the wipes grouped together and the soils were also clustered, except for one site (Fig 2).
The concentration of PAHs in urban soils located in close proximity to residential structures may increase the risk of inhalation, ingestion, or dermal contact exposures to these pollutants . Therefore, information describing the concentrations and sources of PAHs in domestic dust and soils is important as part of the development of interventions to reduce potential adverse health outcomes among exposed populations. Since the health impacts of exposure to PAHs are potentially serious and little is known about the health impacts of domestic exposures, a study intended to characterize domestic exposure to PAHs and other contaminants among residents of an environmental justice community located in Houston, TX, was initiated by Texas A&M University and community partners t.e.j.a.s. in December 2016, which provided baseline data for the current study. After the collection of this data, this area was impacted by Hurricane Harvey, providing an opportunity to assess the potential for PAHs to be redistributed after a major flooding event.
Our small pre-post Hurricane Harvey study demonstrated redistribution of PAHs in an environmental justice neighborhood located in Houston, TX. While this study is small, and direct comparison is not possible due to the different collection methods, the unique ability to compare pre- and post-Hurricane sampling locations enabled an understanding of molecular changes following disaster conditions. Since pre-disaster samples are rarely available for comparison, this study advances our understanding of the potential environmental health impacts of disasters.