Thirty samples of gastropod shells belonging to Nerita albicilla and Canarium (Gibberulus) gibbosus from 15
stations along the Egyptian Red Sea coast were selected for chemical analysis. The analysis indicated that
Nerita is a geochemical marker for a sizeable group of trace elements including; Cu, Pb, Zn, Ag, Th, Ba, Tl, S,
Sc and Se, while Canarium is a good accumulator of the elements, Mo, U, Au and K. Both species have the
same selectivity for Ni, Mn, Fe, As, Sr and P. The differences in sensitivity between the two species are