Chemical speciation of metals in sediment and their bioaccumulation in fish on three rivers around Dhaka City, Bangladesh

As a forward step to understand the metal bioaccumulation in fish species, a study of trace metal speciation of sediment was achieved. Trace metals were measured in sediments and two fish species, Heteropneustes fossilis and Trichogaster fasciata by using inductively coupled plasma mass spectrometer (ICP-MS). Abundance of total trace metals in sediments varied in the following decreasing order: Cr > Ni > Pb > Cu > As > Cd. Sequential extraction tests revealed that the studied metals were predominantly associated with the residual fraction, followed by the organically bound phases. The range of metal content in fishes were Cr (1.8–4.8), Ni (1.0–3.1), Cu (2.5–7.2), As (0.22–0.43), Cd (0.011–0.068) and Pb (0.85–2.7 mg/kg fw), respectively. The rank of biota-sediment accumulation factors (BSAFs) for both species were in the descending order of Cu > Pb > As > Ni > Cr > Cd. Metals accumulation in fish exceeded the international permissible standards suggests that these species are not suitable for human consumption. Keywords—chemical speciation, sediment, fish, bioaccumulation, Bangladesh