Determination of toxicokinetic parameters for bioconcentration of water-soluble fraction of petroleum hydrocarbon associated with no. 0 diesel in Changjiang estuary and Jiaozhou bay: model versus mesocosm experiments.
A method is proposed for determination of toxicokinetic parameters for bioconcentration by phytoplankton of the water-soluble fraction (WSF) of petroleum hydrocarbon (PH) associated with No. 0 diesel, in which WSF-PH concentration in phytoplankton cells, C(A(d)), is estimated by subtracting concentration in water (S-bottle) containing a phytoplankton sample from that in a C-bottle without phytoplankton. It was demonstrated that C(A(d)) agrees well with the concentration found by direct ultrasonication extraction of collected cells, C(A(ind)) ( r = 0.88, p < 0.0001), and its uncertainty was about 17.6%. Mesocosms in 25-m3 ethylene vinyl acetate or 4-m3 polyethylene bags were performed at two sites in China: Changjiang Estuary in spring/summer 1998 and Jiaozhou Bay in autumn 1999 and spring/summer 2000. The experiments were designed to determine toxicokinetic parameters, including specific rates of uptake and elimination, and bioconcentration factor (BCF), for bioconcentration of WSF-PH by phytoplankton. A modified kinetic two-compartment model for bioconcentration of WSF-PH by phytoplankton was developed to estimate the toxicokinetic parameters. In the model, the influence of phytoplankton growth on bioconcentration and WSF-PH decline due to biotic and abiotic processes other than bioconcentration, such as volatilization, microbial degradation, phytolysis, and sorption expressed as an exponential-decay equation, are taken into account. Size-dependent BCF was observed in the laboratory experiment. BCFs were 1.0 x 10(4) in summer in Changjiang Estuary, 1.6 x 10(4) in summer, and 1.1 x 10(4) in autumn in Jiaozhou Bay. The difference in BCF may be interpreted by its size dependence.
Wang
X
X
School of Chemistry and Chemical Engineering, Ocean University of Qingdao, 5 Yushan Rd., Qingdao 266003, P.R. China. xlwang@mail.ouqd.edu.cn
Zhang
J
J
Shi
X
X
Zhu
C
C
An
Y
Y
Jun
S
S
Li
R
R
Zhu
M
M
Chen
S
S
D001682:Biological Availability; D002274:Carcinogens, Environmental / Q000032:analysis / Q000493:pharmacokinetics / Q000633:toxicity*; D020387:Food Chain; D005742:Gasoline / Q000032:analysis / Q000633:toxicity*; D007700:Kinetics; D008962:Models, Theoretical; D010839:Phytoplankton; D012995:Solubility; D018675:Toxicity Tests / Q000379:methods; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000493:pharmacokinetics / Q000633:toxicity*
D002274:Carcinogens, Environmental; D005742:Gasoline; D014874:Water Pollutants, Chemical