Remediation of diesel contaminated sediments by worms (Perinereis sp.) bioturbation

Abstract

Impacts of bioturbation by worms on remediation of diesel contaminated sediments were studied in a laboratory experiment. The total petroleum hydrocarbons (TPH) were represented by the oil or diesel particles which were detected in seawater as well as in the upper, middle and lower layer of sediments at every three days of experiment. The whole experiment was lasted for 21 days and the TPH in the worms was measured by fluorescence analysis and the components of residual oil in the sediments were detected by gas chromatography-mass spectrometry (GC-MS) at the end of the experiment. The results showed that the TPH were declined to 18.37±0.62 and 20.85±1.74 mg/kg in the surface and
sub-surface sediments, respectively, which were the worms’ frequently active areas. TPH was found to increase slightly in deeper sediments as well as in the water column because of bioturbation by worms. The feeding behavior of worms led to the accumulation of TPH in the worm’s body and was reached from 0.998±0.171 to 23.764±3.878 mg/kg. Many components of the diesel such as alkanes, Polycyclic Aromatic Hydrocarbons (PAHs) etc. were removed through bioturbation by worms. In conclusion, the petroleum hydrocarbons in the area where the worms are located will decrease over time.