Dissolved/dispersed polycyclic aromatic hydrocarbon spatial and temporal changes in the Western Gulf of Mexico

Oil extraction and transport activities in the Gulf of Mexico (GoM), along with major marine oil spills riverine inputs, are exerting environmental pressure on this system by increasing concentration oil-related pollutants such as polycyclic aromatic hydrocarbons (PAHs). To fully identify these changes related to activities, current PAH levels should be established. Here, we present low molecular weight/high weight (LMW/HMW) ratios obtained Perdido Fold Belt area surface bottom water at four cruises from May 2016 September 2017. The 1 (P1) cruise was conducted 2016, 2 (P2) September–October 3 (P3) June 2017, 4 (P4) Samples were taken during each up 3,500-m depth, deepest ever recorded for GoM. Results show that highest concentrations PAH, LMW PAHs, HMW PAHs found P4 (1.15, 1.05, 0.10 µg/L, respectively), well below 300 µg/L guideline acute exposure. LMW/HMW only P1 indicates pyrogenic hydrocarbons, while P2, P3, petrogenic. spatial distribution total LMW, showed higher values southern northeastern areas, except P4, which high inputs. complex hydrodynamic region have a significant effect seasonal changes, river contributions, eddy circulation, fronts promote their dispersion.