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Two-Compartment Kinetic Modeling of Radiocesium Accumulation in Marine Bivalves under Hypothetical Exposure Regimes
journal contribution
posted on 2016-01-29, 00:00 authored by Ke Pan, Qiao-Guo Tan, Wen-Xiong WangInterpreting
the variable concentrations of 137Cs in
the field biological samples requires mechanistic understanding of
both environmental and biological behavior of 137Cs. In
this study, we used a two-compartment model to estimate and compare
the 137Cs biokinetics in three species of subtropical marine
bivalves. Significant interspecific difference of 137Cs
biokinetics was observed among oysters, mussels, and scallops. There
was considerable 137Cs assimilation from phytoplankton
in the bivalves, but the calculated trophic transfer factors were
generally between 0.04 and 0.4. We demonstrated a major efflux of
radiocesium in the scallops (with a rate constant of 0.207 d–1), whereas the efflux was comparable between oysters and mussels
(0.035–0.038 d–1). A two-compartment kinetic
model was developed to simulate the 137Cs accumulation
in the three bivalves under four hypothetical exposure regimes. We
showed that the bivalves respond differently to the exposure regimes
in terms of time to reach equilibrium, equilibrium concentration,
and maximum concentration. Bivalves suffering more frequent intermittent
exposure may have higher maximum concentrations than those receiving
less frequent exposure. The interspecific difference of 137Cs accumulation in bivalves has important implications for biomonitoring
and implementing management techniques. This study represents one
of the first attempts to combine both dissolved and dietary pathways
to give a realistic simulation of 137Cs accumulation in
marine bivalves under dynamic exposure regimes.