Krupp, F. & Fleming, R. (eds.), Establishment of a Marine Habitat and Wildlife Sanctuary for the Gulf Region. Final report of phase III. Jubail, Frankfurt a.M.

Petroleum Hydrocarbons in Marine Sediments and Biota 3½ Years after the Gulf War Oil Spill

A b s t r a c t: Many of the salt-marsh and mangrove plants in very heavily oiled intertidal areas have taken up to three years to die since the Gulf War oil spill. Oil loadings responsible for partial and total plant mortalities in some of these areas are characterised. Concentrations of the weathered oil in excess of 7.15 kg/m2 for Arthrocnemum macrostachyum (salt-marsh), 4,56 kg/m2 for Halocnemum strobilaceum (salt-marsh) and 2,12 kg/m2 for Avicennia marina (mangrove) are expected to cause 100 % mortality after a period of a few years, The significance of these results is discussed. Oil contaminated groundwater was not observed to migrate from buried oiled sediments to adjacent non-oiled sediments in the fine-grained, low energy salt-marsh and mangrove sites, The sediments beneath the tar pavements and some of the very heavily oiled intertidal areas (i.e. 47 g/kg) were found to represent the least degraded oiled sediments in the Sanctuary. The ploughing of some of the tar covered sediments in 1992 caused a significant increase in the rate of degradation of the oil which was observed in both 1993 and 1994, However, the total weight of oil extracted from the sediments appears to have changed little from the 1993 to 1994 sampling period. It is also comparable between the ploughed and adjacent non-ploughed sediments. Greatest hydrocarbon degradation was observed in a high energy intertidal environment compared to a relatively low energy site. Concentrations of total oil were similar for the 1992 and 1994 sampling periods at the low energy site, whereas erosion at the upper intertidal of the high energy site may have removed oiled sediments to the lower intertidal zone. The juvenile mullet (Mugil sp.) observed to graze on the benthic algae overlying the intertidal oil were found to ingest measurably more aliphatic hydrocarbons than fish from 3 control site.