Origin of TPHs and PAHs in the marine sediment nearby oil and gas extraction sites on the west coast of Qatar

Abstract

Total Petroleum Hydrocarbons (TPHs) and Polycyclic Aromatic Hydrocarbons (PAHs) are priority pollutants, which are known to be associated with petroleum products. They are released into the marine environment via accidental spillage, exploration and transportation. The present study aims to investigate the type, origin and weathering of petroleum in the coastal marine sediment of the western coastline of Qatar. Sixty-six surface sediment samples were collected along the western coastal area. The concentrations of organic hydrocarbons (TPHs and PAHs) were determined using GC-FID and GC-MS, respectively. Sediment characteristics including pH, temperature, TOC and particle size were also measured. The results indicated low concentrations of TPH (<0.001-0.246 µg/g dry weight sediment) and PAHs (<0.001-0.044 µg/g dry weight sediment). The concentrations for both organic pollutants were lower compared to the previous studies done within Qatar and in the Arabian Gulf and also indicated below the available permissible limit set by the Ministry of Municipality and Environment of Qatar and other Sediment Quality Guidelines (SQGs) used worldwide (NOAA). Pollution concentration profile is site specific where concentrations are high within the proximity of the source and derived from both direct inputs of petrogenic and pyrogenic contribution.