Toxicokinetics of polycyclic aromatic hydrocarbons inEisenia andrei(Oligochaeta) using spiked soil

Abstract
The accumulation of four polycyclic aromatic hydrocarbons ([PAHs]; phenanthrene, pyrene, fluoranthene, and ben‐zo[a]pyrene) was tested in the earthwormEisenia andreiin a spiked artificial soil medium. A typical peak in the body residues was observed for all PAHs around day 7, which could not be explained from changes in the total soil concentration. It is argued that the most likely cause of this peak is a decrease in the concentration in pore water, the main bioavailable phase for earthworms. This decrease is caused by biodegradation while the low rate of mass transfer from the solid state precludes replenishment. To describe the data, bioavailability was assumed to decline exponentially in time, but the shape of the accumulation curves suggests a more abrupt change. Estimates of the uptake rate (k1) are similar for all PAHs when expressed on soil solution basis (approximately 2,000 L/kg/d); the elimination rate (k2) shows a decrease withKowas expected, but the values tend to be slightly lower than literature data. The dynamic bioconcentration factors (k1/k2) agree well with an equilibrium partitioning between soil water and the phases inside the organism.

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