A dynamic model to estimate the activity concentration and whole body dose rate of marine biota as consequences of a nuclear accident.

This paper describes a dynamic compartment model (K-BIOTA-DYN-M) to assess the activity concentration and whole body dose rate of marine biota as a result of a nuclear accident. The model considers the transport of radioactivity between the marine biota through the food chain, and applies the first order kinetic model for the sedimentation of radionuclides from seawater onto sediment. A set of ordinary differential equations representing the model are simultaneously solved to calculate the activity concentration of the biota and the sediment, and subsequently the dose rates, given the seawater activity concentration.

Soil-to-soybean transfer of (99)Tc and its underground distribution in differently contaminated upland soils.

Pot experiments were performed in a greenhouse to investigate the soil-to-soybean transfer of (99)Tc in two different upland soils labeled with (99)TcO4(-) in two contrasting ways. One was to mix the soil with a (99)TcO4(-) solution 26 d before sowing (pre-sowing deposition: PSD), and the other was to apply the solution onto the soil surface 44 d after sowing (growing-period deposition: GPD). The soil-to-plant transfer was quantified with the transfer factor (TF, ratio of the plant concentration to the average of at-planting and at-harvest soil concentrations) or the aggregated transfer factor (TFag, ratio of the plant concentration to the deposition density).

Radiation exposure to marine biota around the Fukushima Daiichi NPP.

The dose rates for six marine organisms, pelagic fish, benthic fish, mollusks, crustaceans, macroalgae, and polychaete worms, representative in marine ecosystems, have been predicted by the equilibrium model with the measured seawater activity concentrations at three locations around the Fukushima Daiich nuclear power plant after the accident on March 11, 2011. Model prediction showed that total dose rates for the biota in the costal sea reached 4.8E4 μGy/d for pelagic fish, 3.

Time-dependent transfer of 137Cs, 85Sr and 65Zn to earthworms in highly contaminated soils.

The transfer characteristics of (137)Cs, (85)Sr and (65)Zn to earthworms (Eisenia andrei) in soils with different amounts of the radionuclides have been investigated. The time-dependent whole-body concentration ratios (CR) were derived for worms in artificially contaminated soils with three different activity concentrations. Two parameters of a first order kinetic model, the equilibrium concentration ratio (CR(eq)) and the effective loss rate constant (k), were estimated by a comparison of experimental CR results with model predictions.

Transport behavior and rice uptake of radiostrontium and radiocesium in flooded paddy soils contaminated in two contrasting ways.

In order to investigate the transport behavior and rice uptake of radiostrontium and radiocesium in flooded rice fields, lysimeter experiments with two paddy soils were performed in a greenhouse. A solution containing (85)Sr and (137)Cs was applied in two different ways - being mixed with the top soil 27 d before transplanting or being dropped to the surface water 1d after transplanting. Rice uptake was quantified with two kinds of transfer factor - TF(m) (dimensionless) and TF(a) (m(2)kg(-1)-dry) for the pre- and post-transplanting depositions, respectively.

Radioecological studies in Korea atomic energy research institute, KAERI.

Regarding the assessment of the terrestrial food chain dose to man, radioecology may be the field that is focused on the transfer of radionuclides from environmental media to food crops. In Korea, the environmental transfer of radionuclides to staple food crops have been investigated at Korea Atomic Energy Research Institute (KAERI) for the last 25 y mainly through radiotracer experiments in greenhouses. As a result, several hundreds of parameter values for the prediction of the radionuclide transfer have been produced.

Approach to non-human species radiation dose assessment in the Republic of Korea.

This paper describes the approach to non-human species radiation dose assessment in Korea. As the tentative reference organisms, one plant and seven animals were selected based on the new International Commission on Radiological Protection recommendation issued in 2007, and the size of the selected organisms was determined from the corresponding Korean endemic species. A set of 25 radionuclides was considered as a potential source term of causing radiological damage to organisms.

Root uptake of radionuclides following their acute soil depositions during the growth of selected food crops.

Greenhouse experiments were performed to investigate the root uptake of radionuclides following their acute soil deposition during the growth of several food crops. For this purpose, the soil under the standing plants was contaminated without any direct contamination of their stems or leaves. The intention of this design was to differentiate foilar uptake and root uptake subsequent to a radionuclide deposition during the vegetation period.

Effects of the simultaneous application of potassium and calcium on the soil-to-Chinese cabbage transfer of radiocesium and radiostrontium.

Pot experiments were carried out in a greenhouse to investigate how effectively the transfer of radiocesium and radiostrontium from soil to Chinese cabbage could be reduced by applying K and Ca simultaneously to the soil. The sources of these elements were KCl and Ca(OH)(2) at agrochemical grades. Varying dosages of K and Ca were tested for an acid loamy soil treated with a mixed solution of (137)Cs and (85)Sr at two different times - 3 d before sowing and 32 d after sowing.

Tritium levels in Chinese cabbage and radish plants acutely exposed to HTO vapor at different growth stages.

To simulate an acute exposure of Chinese cabbage and radish plants to airborne HTO, the potted plants were exposed to HTO vapor under semi-outdoor conditions for 1h at different times from the early to late growth stages. The plants were grown outdoors and the plant tritium was measured at the end of an exposure (h(0)) and at harvest. The leaf tissue free water tritium (TFWT) concentrations at h(0) were considerably lower than estimated equilibrium concentrations.

A dynamic compartment model for assessing the transfer of radionuclide deposited onto flooded rice-fields.

A dynamic compartment model has been studied to estimate the transfer of radionuclides deposited onto flooded rice-fields after an accidental release. In the model, a surface water compartment and a direct shoot-base absorption from the surface water to the rice-plant, which are major features discriminating the present model from the existing model, has been introduced to account for the flooded condition of rice-fields. The model has been applied to the deposition experiments of 137Cs on rice-fields that were performed at three different times to simulate the deposition before transplanting (May 2) and during the growth of the rice (June 1 and August 12), respectively.