TOXICITY AND PERSISTENCE OF NEARSHORE SEDIMENT CONTAMINATION FOLLOWING THE 1991 GULF-WAR

In January 1991, the world's largest oil spill inundated extensive coa stal areas of the Gulf with massive quantities of crude oil. In August 1993, the authors collected sediment samples from eleven beach sites at four tidal elevations in Kuwait and Saudi Arabia. Ten-day static se diment toxicity tests with the marine amphipod Rhepoxynius abronius re vealed significant sediment toxicity (reduced survival) at five sites. Infrared spectrometry indicated that the highest concentrations of pe troleum hydrocarbons occurred at these same five sites. Other variable s such as ammonia concentration, silt and clay content, and total orga nic matter in the sediment had no affect on amphipod survival, Concent rations of petroleum hydrocarbons greater than about 1 mg g(-1) dry se diment caused significant amphipod mortality, Such toxic sediment conc entrations occurred at Al Khiran, Kuwait, and along an extensive coast al area of Saudi Arabia from Ras Tanajib to Abu Ali (a distance of ove r 100 km). The overall area of sediment toxicity corresponds closely t o the spill trajectory and presence of sea surface petroleum as record ed on airborne radar soon after the spill (9 March 1991). These result s indicate that sediment toxicity from the world's largest oil spill p ersisted for at least 30 months, Additionally, petroleum hydrocarbon c oncentrations in the sediments of contaminated sites were sufficiently high to cause continued leaching of oil to the sea-surface. (C) 1998 Elsevier Science Ltd.