Application of nuclear analytical techniques for assessment of coastal impact

Marine sediments contain a record of past events and proved to be an interesting indicator matrix for this study. Instrumental neutron activation analysis and energy dispersive X-ray fluorescence techniques offer adequate sensitivity for analysis of trace elements. Grain size analysis of sediment samples before and after tsunami showed a shift in textural characteristics of the sediment which is not observed during regular monsoon and seasonal changes. Some general characteristics of sediments revealed sand content ranges between 39 and 65% and silt from 33 to 53%. Clay content was found low averaging 5.4% and varied from 2 to 13% (by weight). The concentration of Cu, Ni, Fe, Pb, Zn, Mn, Rb, Sr, Ti, K, and Ca varies from 12 to 53, 19-46, 21,952-36,785, 21-39, 39-67, 335-856, 47-61, 223-400, 4,991-8,054, 11,000-15,791, and 5,878-11,214 mg kg(-1), respectively. The positive correlation was observed for Cu, Ni, Ti, K, and Rb with respect to Fe. The negative correlation was observed for Ca, Sr, Zn, and Pb with respect to Fe, indicating the different source for these metals in the marine sediment. Decrease of the particle-reactive element in the tsunami impacted sediment indicates removal of clay component in the sediment, which is supported by the presence of low Th/U ratio.