Polycyclic Aromatic Hydrocarbons in Houston Parks After Hurricane Harvey.

Unprecedented inland precipitation and catastrophic flooding associated with Hurricane Harvey potentially redistributed contaminants from industrial sites and transportation infrastructure to recreational areas that make up networks of green infrastructure, creeks, and waterways used for flood control throughout the Greater Houston Area. Sediment samples were collected in parks located near the Buffalo Bayou watershed 1 week after Hurricane Harvey made landfall and again 7 weeks later. Total concentrations of the U.S. Environmental Protection Agency's (EPA's) 16 priority polycyclic aromatic hydrocarbons (PAHs) were measured in each sample at both time points. Diagnostic ratios were calculated to improve understanding of potential sources of PAHs after flooding. Diagnostic ratios suggest vehicular traffic to be a potential source for PAHs in parks. Although the concentrations of PAHs in all samples were below EPA actionable levels, given that no background values were available for comparison, it is difficult to quantify the impact flooding from Hurricane Harvey had on PAH concentrations in Houston parks. However, given the high frequency of flooding in Houston, and the concentration of industrial facilities and transportation infrastructure adjacent to recreation areas, these data demonstrate that PAHs were still present after unprecedented flooding. This study may also serve as a baseline for future efforts to understand the environmental health impacts of disasters.

Spatial Distribution of Polycyclic Aromatic Hydrocarbon Contaminants after Hurricane Harvey in a Houston Neighborhood.

BACKGROUND: Hurricane Harvey made landfall along the Texas Gulf Coast as a Category 4 hurricane on August 25, 2017, producing unprecedented precipitation that devastated coastal areas. Catastrophic flooding in the City of Houston inundated industrial and residential properties resulting in the displacement and transfer of soil, sediment, and debris and heightening existing environmental justice (EJ) concerns. OBJECTIVES: The primary aim of this study was to evaluate the presence, distribution, and potential human health implications of polycyclic aromatic hydrocarbons (PAHs) in a residential neighborhood of Houston, Texas following a major hurricane. METHODS: Concentrations of PAHs in 40 soil samples collected from a residential neighborhood in Houston, Texas were measured. Spatial interpolation was applied to determine the distribution of PAHs. Potential human health risks were evaluated by calculating toxicity equivalency quotients (TEQs) and incremental excess lifetime cancer risk (IELCR). RESULTS: Total priority PAH concentrations varied across samples (range: 9.7 × 101 ng/g-1.6 × 104 ng/g; mean: 3.0 × 103 ng/g ± 3.6 × 103 standard deviation). Spatial analysis indicated a variable distribution of PAH constituents and concentrations. The IELCR analysis indicated that nine of the 40 samples were above minimum standards. CONCLUSIONS: Findings from this study highlight the need for fine scale soil testing in residential areas as well as the importance of site-specific risk assessment. COMPETING INTERESTS: The authors declare no competing financial interests.

A Spatial Analysis of Possible Environmental Exposures in Recreational Areas Impacted by Hurricane Harvey Flooding, Harris County, Texas.

Hurricane Harvey made landfall on the Texas Gulf Coast in August 2017 causing catastrophic flooding. Harris County is highly vulnerable to flooding, which is controlled in part by a system of bayous that include parks and trails. The petrochemical industry, as well as thousands of documented sources of environmental pollution make recreational areas susceptible to environmental contamination during flood events. Recreational areas and toxic exposure sources were geocoded by subwatershed boundaries and overlaid with the area of Hurricane Harvey inundation. A total of 121 of 349 (36.78%) parks were flooded; 102 of 121 (84.30%) were located in subwatersheds with at least one exposure source. A total of 337 exposure sources (6 Superfund, 32 municipal solid waste, and 299 petroleum storage tanks) in 30 subwatersheds were flooded. Though parks provide flood mitigation and other postdisaster benefits, their susceptibility to environmental contamination should be considered, especially in areas with a large number of toxic exposure sources.

Using Spatial Analysis to Examine Potential Sources of Polycyclic Aromatic Hydrocarbons in an Environmental Justice Community After Hurricane Harvey.

Polycyclic aromatic hydrocarbons (PAHs) are environmental contaminants associated with adverse human health outcomes. Environmental justice neighborhoods experience disproportionate environmental health risks. Hurricane Harvey made landfall on August 25, 2017, bringing record rainfall and catastrophic flooding to Houston, Texas, redistributing PAHs in residential soil. We aimed to describe PAH distributions in soil in the Manchester neighborhood of Houston, TX, and identify their potential sources. Soil samples were collected from 24 residential addresses and analyzed for 16 priority PAH concentrations using an accelerated solvent extractor. PAH distribution and source determination were conducted using spatial analysis and isomer ratios. All sample sites detected PAHs in soil, with the total mass ranging from 0.75 to 69.9 ng/g, which were predominantly four-ring structured PAHs. Total PAH concentrations were highest on the northeastern border of the neighborhood, whereas lower overall concentrations of PAHs were found on the southwestern border, at the highest elevation in the watershed. The ratio indeno[1,,3-cd]pyrene (IP) to indeno[1,,3-cd]pyrene plus benzo[ghi]perylene indicated vehicular combustion as the primary source in 19 of 23 samples. After heavy rainfall from Hurricane Harvey in the Manchester neighborhood, PAHs in soil were unevenly distributed throughout the neighborhood, with an accumulation of PAHs in the northeastern edges. Using isomer ratios and spatial analysis, the likely source of PAHs is from use of transportation infrastructure.

Comparing residential contamination in a Houston environmental justice neighborhood before and after Hurricane Harvey.

INTRODUCTION: 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. METHODS: 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. RESULTS: 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. DISCUSSION: 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.