Accumulation, release, and depuration of crude oil-in water emulsions by the bivalve Corbicula fluminalis muller (Molluscs : Bivalia : Eulamellibranchiata : Corbiculidae)‎ from Shatt al-Arab River, Basrah, Iraq

Abstract EN

The bivalve C.

fluminalis was exposed to a single doses of sublethal concentrations (20, 60 and 120 ppm) of Basrah regular crude oil-in water emulsions for a month period, under the laboratory conditions.

The pattern of accumulation and release of petroleum hydrocarbons, the depuration time (biological half-life, TB50), and the mechanisms of transport of petroleum hydrocarbons into the bivalve were determined.

The bivalve accumulated the highest amount of petroleum hydrocarbons during the first week of exposure to crude oil emulsions.

The accumulated petroleum hydrocarbons decreased each week as the petroleum hydrocarbons content of the exposure water decreased.

The capillary gas chromatography analysis revealed that the dominant petroleum hydrocarbons accumulated by the bivalve after the four weeks of exposure to crude oil emulsions were naphthalene, phenanthrene, C12, C13, and C14.

The depletion of petroleum hydrocarbons from the exposure water, and the accumulation and release of petroleum hydrocarbons by the C.

fluminalis involved formation a complex of mucus and crude oil by the bivalve.

The depuration period was began when the bivalve was transferred to a clean river water for two weeks subsequent to the month exposure to crude oil emulsions.

The accumulated petroleum hydrocarbons were rapidly, although incompletely released.

At the end of the depuration period, the capillary gas chromatography analysis showed that the petroleum hydrocarbons retain in the bivalve was naphthalene.

The biological half-life (TB50) for depuration of the bivalve calculated were 55 days, 14.5 days, and 18 days for 20 ppm, 60 ppm, and 120 ppm respectively.