Assessment of Dissolved/ Dispersed Aliphatic and Aromatic Hydrocarbon Pollution in Seawater at the Clifton Beach on the Karachi Coast

Abstract

Sea water samples collected at different depths from 10 stations along the Clifton beach of Karachi Coast were analyzed for dissolved/dispersed polyaromatic and aliphatic hydrocarbons (PAHs and AHs) by GC and GC-MS. Sampling was performed in august 2003, just after the Tasman Spirit oil spill and in august 2003. Levels of total polycyclic aromatic hydrocarbon (PAHs) and aliphatic hydrocarbons (AHs) were 8.20-26.35 µg L−1 (Σ 16 PAHs) and 5.23-21.005 µg L−1 (Σ 16 AHs), respectively. Values decreased later on till lower than 0.02-0.25 ug L−1 possibly representing the background level of the region, exhibited lower concentrations that ranged from 0.02-0.05 µg L−1 (Av. 0.15 µg L−1 Σ 16 PAHs and 0.05–0.2 µg L−1 Σ 14 aliphatic hydrocarbons) with decreasing to 0.07 µg L−1 of PAHs with depth in the water. In September 2005, the concentrations were rather uniform, averaging 0.05 µg L−1 (Σ 16 PAHs) and 4.08 µg L−1 Σ 14 aliphatic hydrocarbons.