Bioconcentration of trace metals in mesozooplankton an important contaminant route to higher trophic levels

As a part of coastal monitoring programme, we examined the concentration of 12 different trace elements in mesozooplankton (MZP) to understand their bioaccumulation potential in the coastal waters of southwestern Bay of Bengal. Dissolved metal concentrations followed the order Fe > Zn > Cu > Pb > U> Cr > Mn > NI> La > Cd> Ce > Co, whereas, concentration in MZP tissues followed the trend of Fe > Zn > Mn > Cr> Ni > Pb > Cu > Ce > La > Co > U> Cd. Summer season was found to have more metal concentration in the water and MZP tissue than the southwest (SWM) and north east monsoon (NEM) seasons. The bioconcentration factor (BCF) always remained greater than 1 (>1) indicating the active accumulation of metals by MZP. The sequential trend of BCF was Mn > Ce > Fe > Cr > Pb > Ni > Co > La > Zn >Cu > Cd> U. This study has provided a novel insight into metal distribution in MZP, main food constituents of most fishes in the coastal waters, play a major role in transfer of metals in the food chain. (author)