RECENT BIOREMEDIATION RESULTS ON OIL SPILLEDDURING THE 1991 GULF WAR

摘要

Over thirteen years ago, Iraqi soldiers caused the release of overrn10 million barrels of oil into Arabian Gulf waters from variousrnsources. The oil impacted the majority of the western Gulf shoreline,rnestimated at over four hundred miles. Coastal development isrnhaving to deal with oil which was buried, stock-piled, or otherwisernleft in place. One such development is underway at Al Khiranrn(southern Kuwait) where oil is within planned construction areasrnfor public beaches,rnhousing lots, a marina, and channels. Although the oil isrnweathered and generally considered non-toxic (based on chemicalrnanalyses below), expanses of it pose physical and esthetic problemsrnfor construction and human use of the areas. Tests were performedrnusing various means of treating this oil, and the results arerngiven herein.rnA variety of bioremediation methods was tested, including thernuse of products from four companies, selected at random fromrnthe oil spill chemical industry (U.S. and abroad). All four werernbacterial powders, with nutrients included or added separately,rnapplied according to manufacturers' specifications. Test plots werernon mildly contaminated soil (33 mg/kg total hydrocarbons) whichrnhad oil mixed throughout. Plots were located in the upper intertidalrnzone, where they were exposed to minimal (<30 cm), diurnal,rnhigh tide flooding, and the research site was protected from wavernand wind action by a levee. Extreme conditions at the sites includedrnhigh temperatures, lack of rainfall, and flushing by highrnsalinity seawater (40 parts per thousand salt).rnSites were sampled before treatment, and at various timesrnbeginning 44 days after treatment. Composite samples were collectedrnfrom each test plot and analyzed for total petroleum hydrocarbonsrn(TRPH), and for three hydrocarbon ranges: C8-C10,rnC10-C28, and C28-C40. Results showed no significant reductionrnin total hydrocarbons by any product, compared to pre-treatmentrnlevels. Aggressive physical tilling of contaminated soils at arnsecond site provided some reduction in total hydrocarbons duringrnthis period. Various methods were tried in the next phase of testing,rnincluding additional product exposure time, increased tilling, and screening. The results provide guidelines for the use of chemicalrnproducts and physical treatments, in extreme coastal condi-rnconditions,rnfor the treatment of weathered hydrocarbons.