Characterisation of colloids in coastal groundwater special focuses on their association with cs and sr

The colloids serve as the medium of transport especially for the trace metals and radio nuclides and hence have attained significancein the recent times. Two bore wells were selected for the study representing hard rock formation (Anupram) and sedimentary formation (Kalpakkam). Samples were collected during northeast monsoon and south west monsoon. Colloidal fractions of 1.2 µm, 0.8 µm, 0.45 µm and 0.22 µm.sizes were extracted.The surface charge was determined by zeta potential and average particle size was determined by particle size analyses through dynamic light scattering. The morphological studies by scanning electron microscope (SEM) show that saccroidal texture in Anupram (Charnockite formation) and almost spherical structure in Kalpakkam due to sedimentary terrain condition (Clayey sand). The elongated octahedral texture proves that the predominance clay mineral is kaolinite. The mineralogical characterization studies reveal that the Muscovite, Chlorite, Illite and Kaolinite peaks in FTIR analysis. Sr concentration was observed to increase in the finer fractions in Anupuram and decreasing trend was observed in Kalpakkam but an irrespective value of Cs in colloidal fractions at Anupruam. The negative surface charges of particles indicate that the groundwater colloids present in the groundwater of this region tend to attach positive contaminants like Cs and Sr respectively.