Distribution of oil and grease and petroleum hydrocarbons in the straits of Johor, Peninsular Malaysia

Seawater and surface sediments were collected from 31 stations along the Johor straits. Oil, grease and petroleum hydrocarbons were found at all stations. Oil and grease concentrations in water ranged from 0.270 to 3.534 mg per litre, and those of petroleum hydrocarbons from 0.001 to 0.135 and from 0.025 to 2.795 mg per litre expressed as chrysene and Seligi crude oil equivalents, respectively. The highest petroleum hydrocarbon concentrations were found at stations near the principal shipping lane of the Malacca straits, where they approached the oil and grease concentrations. At most stations there was a substantial contribution from non-petrogenic pollutants. Three distant stations showed low sediment concentrations of petroleum hydrocarbons, which could be regarded as background concentrations, but concentrations in water were relatively high reflecting seasonal tidal patterns.