Abstract
A field study was initiated in December 2000 in two selected sub-Antarctic soils (Kerguelen Archipelago) with the objective of determining the long-term effects of a fertilizer addition on the degradation rate and the toxicity of oil residues under severe sub-Antarctic conditions. Two soils were selected. The first site was an organic soil supporting an abundant vegetal cover while the second one was a mineral soil, free from vegetation. Both soils were located in the vicinity of the permanent station of Port-aux-Francais (69°42′E−49°19′S). Two series of five experimental plots (0.75 × 0.7 5 m) were settled firmly into each of the studied soils. Each plot received 500 ml of diesel fuel or Arabian light crude oil and some of them were treated with a bioremediation agent: the slow release fertilizer Inipol EAP-22® (Elf Atochem). All plots were sampled on a regular basis over a 4-year period. The microbial response was improved by bioremediation treatments but fertilizer addition had a greater impact on the mineral soil when compared to the organic one. The rate of degradation was significantly improved by bioremediation treatments. However, even after 4 years, the toxicity of oiled soils as determined by Microtox solid phase tests showed a persistent response in spite of an apparent significant degradation of alkanes and aromatics. Despite the very small amount of contaminant used in this experiment, 4 years of bioremediation was not sufficient to obtain a complete return to pristine conditions
Published Version
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