Bioaccumulation Potential of Three Toxic Heavy Metals in Shrimp, Penaeus monodon from Different Fractions of the Culture Environment
S.P.S.D. SENADHEERA AND K.A.S. PATHIRATNE
Concentrations of three toxic heavy metals viz, lead, cadmium and chromium in the muscle tissue of shrimp harvested from selected shrimp farms in the North Western Province of Sri Lanka were determined along with the metal levels in the source water, sediments of the water sources, the farm sediments and formulated shrimp feed used by the farms by Atomic Absorption Spectrophotometry using standard analytical procedures. Bio-transfer factors of the three metals in the muscle tissue of the shrimp were enumerated in relation to source water, sediments of the water sources, farm sediments and to formulated shrimp feed. Levels of lead, chromium and cadmium in the muscle tissue of the shrimp (Mean±SEM) were (in µg g-1 dry weight) 0.360±0.044, 0.610±0.044 and 0.199±0.012 (n=360) respectively. Bio-transfer factors of the three metals in shrimp in relation to water were greater than 1 indicating bioaccumulation of all the metals occurs through the water phase. Of the three metals studied, bio-transfer factors of cadmium from the sediments ranged from 9 to 21 indicating high potential of bioaccumulation via the sediments. However, bio-transfer factors of chromium and lead in shrimp tissue from the sediments were lower than 1. Metal wise comparisons indicated bio-transfer factors of cadmium in shrimp in relation to sediments were significantly higher than that of the other two metals. Bio-transfer factors of the three metals in shrimp from the formulated feed ranged from 0.1 to 0.9.