A Kinetic Study on the Accumulation of No.0 Fuel Oil and Pinghu Crude Oil Water-Accommodated Fraction in Exopalaemon carinicauda

Abstract

The kinetic parameters of No.0 fuel oil and Pinghu crude oil water-accommodated fractions (WAFs) during accumulation and elimination in Exopalaemon carinicauda were quantified using a semi-static two-compartment kinetic model. The accumulation phase data were analyzed via nonlinear regression to obtain kinetic parameters, yielding critical values including the uptake rate constant (k1), elimination rate constant (k2), bioconcentration factor (BCF), equilibrium body burden (CAmax), and biological half-life (B1/2). Modeling results demonstrated distinct kinetic parameters for the two oils. For No.0 fuel oil, the average values were k1 = 5.21; k2 = 0.1105; BCF = 48.98; CAmax = 2.95 mg/kg; and B1/2 = 6.40 days. For Pinghu crude oil, the averages were k1 = 10.25; k2 = 0.1044; BCF = 98.15; CAmax = 8.48 mg/kg; and B1/2 = 6.64 days. The uptake rate constant (k1) and BCF generally decreased with increasing petroleum hydrocarbon exposure concentrations in ambient seawater, while the elimination rate constant (k2) remained relatively constant across different concentrations. CAmax increased proportionally with the petroleum hydrocarbon exposure concentration. Goodness-of-fit tests confirmed that the petroleum hydrocarbon concentrations in the experimental data were well described by the semi-static two-compartment model. Throughout the testing period, the concentration of No.0 fuel oil in Exopalaemon carinicauda remained lower than that of Pinghu crude oil.

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