Abstract

M. Al-Busaidi, P. Yesudhason, A. Al-Waili, W. Al-Rahbi, K. Al-Harthy, N. Al-Mazrooei and S. Al-Habsi

Clam samples of Liochoncha ornata were collected for a period of one year from July 2009 to June 2010
at monthly interval. The soft tissue of clams was analyzed to detect some potentially toxic metals and
polycyclic aromatic hydrocarbons (PAHs). Accumulation of Hg, Cd and Pb in the clam tissues showed
variability with a mean concentration of 0.011±0.009, 1.769±0.942 and 0.015±0.039 µg/g wet weight for
Hg, Cd and Pb, respectively. Cadmium had recorded a particularly high potential of accumulation in L.
ornata. The bioaccumulation of PAHs in the clams appeared to be selective and ranged from 4.80 to
12.0 ng/g; wet weight. The most carcinogenic PAHs, such as benzo (a) pyrene and dibenz (a,h)
anthracene, were in all cases below the limits of detection. No distinctive relationship was found
between different size class and contaminant uptake by the clam. The concentrations of both of Pb and
Hg in L. ornata, were found to be below the safe limits suggested by various authorities and thus gave
no indication of pollution by such elements. However, continuous monitoring of these and other
pollutants in the coastal marine ecosystem is advised.