Factors Effecting Adsorption of ¹³⁷ Cs in Marine Sediment Samples in Marine Sediment Samples from the Upper Gulf of Thailand

Contamination of ¹³⁷Cs in sediment is a far more serious problem than in water because sediment is a main transport factor of ¹³⁷Cs to the aquatic environmental. Most of ¹³⁷Cs in water could be accumulated in sediment which has direct effect to benthos. This study focused on factors effecting the adsorption of 137Cs in marine sediment samples collected from four different estuary sites to assess the transfer direction of ¹³⁷Cs from water to sediment that the study method by treat ¹³⁷Cs into seawater and mixed with different sediment samples for 4 days. The result indicated that properties of marine sediment (cation exchange capacity (CEC), organic matter, clay content, texture, type of clay mineral and size of soil particle) had effects on ¹³⁷Cs adsorption. CEC and clay content correlated positively with the accumulation of ¹³⁷Cs in the marine sediment samples. On the other hand, organic matter in sediment correlated negatively with the accumulation of ¹³⁷Cs in samples. The study of environmental effects (pH and potassium) found that the ¹³⁷Cs adsorption decreased when concentration of potassium increased. The pH effect is still unclear in this study because the differentiation of pH levels (6, 7, 8.3) did not have effects on ¹³⁷Cs adsorption in the samples.