Crude oil bioremediation in sub-Antarctic intertidal sediments: chemistry and toxicity of oiled residues.
The effectiveness of fertilizers for crude oil bioremediation in sub-Antarctic intertidal sediments was tested over a one-year period in a series of ten (10) experimental enclosures. Chemical, microbial and toxicological parameters demonstrated the effectiveness of various fertilizers in a pristine environment where hydrocarbon degrading bacteria (HDB) had not been stimulated by previous accidental spills or human activities. The low temperature of seawater (3-4 degrees C) had no obvious effects on the HDB community and the bioremediation process. Over 90% of n-alkanes were degraded in the first six months and most light aromatics (2-3 rings) disappeared during the first year of observation. The toxicity of oiled residues (Microtox(R) SP) was significantly reduced in the first 6 months of the process, but it increased again in the last months of the experiment. One of the fertilizers containing fishbone compost enriched with urea, inorganic phosphorus and a lipidic surfactant reduced significantly the toxicity of oil residues in the last 3 months of the experiment. Interstitial waters collected below the oil slicks during the remediation showed no toxicity, and even stimulated Vibrio fischeri. When comparing all fertilizers to the control plots, a good correlation (r(2)=0.82) was found between the growth rate of HDB and the degradation rate of n-alkanes in the first 90 days of the experiment only indicating that fertilizers were efficient for at least 3 months but their beneficial effects were lost after 6 months.
Pelletier
E
E
Institut des Sciences de la Mer de Rimouski, Université du Québec à Rimouski, 310 allée des Ursulines, G5L 3A1 Rimouski, Canada. emilien_pelletier@uqar.qc.ca
Delille
D
D
Delille
B
B
D000473:Alkanes / Q000378:metabolism; D000864:Antarctic Regions; D001419:Bacteria / Q000378:metabolism*; D001673:Biodegradation, Environmental; D001681:Biological Assay; D005308:Fertilizers; D019015:Geologic Sediments / Q000382:microbiology*; D007700:Kinetics; D010578:Petroleum / Q000378:metabolism* / Q000633:toxicity*; D012623:Seawater
D000473:Alkanes; D005308:Fertilizers; D010578:Petroleum