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

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.