The rate of removal and the compositional changes of diesel in Antarctic marine sediment
Woolfenden, ENM and Hince, G and Powell, SM and Stark, SC and Snape, I and Stark, JS and George, SC, The rate of removal and the compositional changes of diesel in Antarctic marine sediment, The Science of The Total Environment: An International Journal for Scientific Research Into The Environment and Its Relationship With Man, 410-411, (Online) pp. 205-216. ISSN 0048-9697 (2011) [Refereed Article]
Diesels and lubricants used at research stations can persist in terrestrial and marine sediments for decades, but knowledge of their effects on the surrounding environments is limited. In a 5 year in situ investigation, marine sediment spiked with Special Antarctic Blend (SAB) diesel was placed on the seabed of O'Brien Bay near Casey Station, Antarctica and sampled after 5, 56, 65, 104 and 260 weeks. The rates and possible mechanisms of removal of the diesel from the marine sediments are presented here.
The hydrocarbons within the spiked sediment were removed at an overall rate of 4.7 mg total petroleum hydrocarbons kg−1 sediment week−1, or 245 mg kg−1 year−1, although seasonal variation was evident. The concentration of total petroleum hydrocarbons fell markedly from 2020±340 mg kg−1 to 800±190 mg kg−1,
but after 5 years the spiked sediment was still contaminated relative to natural organic matter (160± 170 mg kg−1). Specific compounds in SAB diesel preferentially decreased in concentration, but not as would be expected if biodegradation was the sole mechanism responsible. Naphthalene was removed more readily than n-alkanes, suggesting that aqueous dissolution played a major role in the reduction of SAB diesel. 1,3,5,7- Teramethyladamantane and 1,3-dimethyladamantane were the most recalcitrant isomers in the spiked marine
sediment. Dissolution of aromatic compounds from marine sediment increases the availability of more soluble, aromatic compounds in the water column. This could increase the area of contamination and potentially broaden the region impacted by ecotoxicological effects from shallow sediment dwelling fauna, as noted during biodegradation, to shallow (b19 m) water dwelling fauna.