Water and sediment oil content spread in Dumai coastal waters, Riau Province, Indonesia

Dumai coastal water is one of coastal area that very active in Indonesia, since it has national and international shipping lanes. Furthermore along coastal waters of Dumai are locate various industries likely influencing coastal environmental water quality. The study aimed to examine oil content in water and bottom sediment. The highest oil content in water was found at Lubuk Gaung station 11 (0.719 ppm), western part of the research location. This might be related to the monsoon season change in which sea water current changes toward west direction during April-May 2015. Sediment oil content at Purnama station 4 (3591 ppm) was the highest. It might be attributed to the existence of industries along the coast. The high oil concentration in sediment might affect coastal ecosystems.