Assessment of toxic heavy metal levels in black tiger shrimp, Peneaus monodon cultured in the northwestern province of Sri Lanka
S.P.S.D. SENADHEERA AND K.A.S. PATH1RATNE
The aim of this study was to determine the levels of three toxic heavy metals; lead, cadmium and chromium in the muscle tissue of the shrimp, Penaeus monodon cultured in the North Western Province (NWP) of Sri Lanka to examine whether the levels of these toxic heavy metals exceed the permissible/guide levels stipulated in the established quality guidelines for human consumption. Lead, cadmium and chromium concentrations in the muscle tissue of the shrimp, P. monodon from selected farms that fed from four selected water sources (Puttalam lagoon, Dutch canal, Mundal lagoon and Gembarandiya lagoon) in the NWP were determined by atomic absorption spectrophotometry using standard analytical procedures.
The levels (Mean±SEM) of lead, chromium and cadmium in the muscle tissue of the shrimp (in µg g-1 wet weight) were 0.096±0.024, 0.200±0.004 and 0.057±0.004 respectively. Even though water source-wise differences could not be detected in relation to the cadmium levels, lead and chromium levels in the shrimp tissue cultured in water from the four water sources were significantly different from each other. However, none of these metals in the shrimp tissue exceeded the maximum permissible levels or the guide levels established by the statutory authorities under fish import/export regulations. The present study indicates that there is no risk of intake of these metals from the shrimp, P. monodon cultured in the NWP of Sri Lanka as the current residue levels in the muscle tissue of the shrimp are within the safety permissible levels for human consumption.