THE NATURE AND EXTENT OF OIL CONTAMINATION ON SAUDI-ARABIAN GULF BEACHES - EXAMINATIONS OF BEACHES OF DAWHAT AD DAFI AND DAWHAT AD MUSALLAMIYA IN SUMMER 1991 AND WINTER 1991/92

In June/July 1991 and in January/February 1992, the oil-polluted Saudi Arabian Gulf Coast between Ras az-Zawr and Jazirat Abu Ali was examined. The distribution of oil, penetration into the sediment, and oil burden per unit area were estimated at 24 stations. The inspected coast was polluted without interruption, and the beaches were oiled over a width ranging from some meters to one kilometer. Pollution extended from an extreme high water line to a line between midwater and low water. The subtidal area appeared to be unaffected. Only one natural remediation process was found. Cyanobacterial mats, naturally occurring in the intertidal zone, are growing exuberantly on top of oiled sediments. On drying, the mats shrink and tear and break up the tar crusts. In addition, the mats seem to support hydrocarbon-degrading bacteria by providing nutrients, moisture, and shelter. Unfortunately, the cyanobacteria-mediated process is found only in the zone which is regularly inundated by tides.