A study of bioaccumulation occurring in a spatial and temporal aquatic environment

The impacts of spatial, temporal, and hydrodynamics on the bioaccumulation in the Chernobyl cooling lake were evaluated using a two-dimensional aquatic exposure assessment model. The model framework integrated spatial and temporal heterogeneity effects of radioactive environments, changes in abundance and distribution of aquatic populations, spatial and temporal dependent (or density-dependent) radionuclide ingestion rates, and population biomass changes. Plankton population growth was integrated into the hydrodynamic-transport model to determine the plankton biomass density change and distributions. The exposure estimation was conducted in a two-dimensional finite element mesh which was used in the hydrodynamic-transport model. Results indicated that bioaccumulation factors with the assumption of steady-state and homogeneous conditions significantly over-estimated the radionuclide concentration accumulated in fish. The impacts of changes of biomass distributions and variable ingestion rates on the bioaccumulation varied spatially and temporally. Results also revealed that a higher radiobiological turn-over rate could be a dominate factor in determining the radionuclide fate in biota when the ecological processes, such as population growth, were relatively slow. Two different predator-prey relationships were applied. Their impacts on the bioaccumulation of fish varied spatially and temporally. Overall, the results suggest that a more realistic physical description of contaminated environments and ecosystems is necessary in studying bioaccumulation occurring in nature