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Suspended particles enhance biodegradation of oil in sea

Loh, Andrew, Shankar, Ravi, Ha, Sung Yong, An, Joon Geon, Yim, Un Hyuk
The Science of the total environment 2019 v.685 pp. 324-331
biodegradation, dispersibility, droplets, evaporation, oils, particulates, petroleum, polycyclic aromatic hydrocarbons, weathering
Biodegradation patterns of oil in four distinct phases were compared over a 14-day series of exposures. The dispersibility and stability of oil droplets in the water column were important factors affecting oil biodegradation. Due to the stability of oil droplets with particle interactions, oil-suspended particulate matter aggregates (OSA) showed a five-fold enhancement in biodegradation compared to non-dispersed oil. The reduction of total petroleum hydrocarbons was highest in OSA (51.45%), followed by chemically dispersed oil (33.5%), oil film (21.6%), and water-accommodated fractions (WAF, 14.3%). Polycyclic aromatic hydrocarbon (PAH) profiles and percentage weathering plots showed that reductions in PAHs in WAF, oil film, and chemically dispersed oil were mainly due to evaporation (41.5–69.5%) and only partially due to biodegradation (7.4–16.3%). However, the reduction of PAHs in OSA was driven more by biodegradation (36.8%) than evaporation (29.7%). The strong PAH–particle interactions in OSA inhibited evaporation of PAHs and enhanced microorganism biodegradation in the water column.