Distributions and accumulation rates of polycyclic aromatic hydrocarbons in the northern Gulf of Mexico sediments

Abstract Sediment samples collected from shelf, slope and interior basin of the northern Gulf of Mexico during 2011–2013, 1–3 years after the Deepwater Horizon (DWH) oil spill, were utilized to characterize \{PAH\} pollution history, in this region. Results indicate that the concentrations of surface ΣPAH43 and their accumulation rates vary between 44 and 160 ng g−1 and 6–55 ng cm−2 y−1, respectively. ΣPAH43 concentration profiles, accumulation rates and Δ14C values are significantly altered only for the sediments in the immediate vicinity of the \{DWH\} wellhead. This shows that the impact of \{DWH\} oil input on deep-sea sediments was generally limited to the area close to the spill site. Further, the \{PAHs\} source diagnostic analyses suggest a noticeable change in \{PAHs\} composition from higher to lower molecular weight dominance which reflects a change in source of \{PAHs\} in the past three years, back to the background composition. Results indicate low to moderate levels of \{PAH\} pollution in this region at present, which are unlikely to cause adverse effects on benthic communities.