Effects of chronic oil pollution in a shallow sub-tropical marine environment

A study of the marine environment off a major oil refinery in the Arabian/ Persian Gulf was carried out in 1986. The study covers an area of some 100 km² and abundance and biomass of benthic fauna as well as oil content of sediments and bivalves were investigated. In addition some physicochemical parameters of water and sediments were measured. The distribution of the fauna corresponds well with the concentrations of oil in the sediment, and an area of 1 km² was considered severely contaminated while about 10 km² was moderately contaminated. This is a considerably smaller area than that found to be contaminated in a similar study in 1981, 5 years earlier. The reason for this is probably decreased quantities of petroleum hydrocarbons released via the effluent.