ASSESSING VARIATIONS IN METAL BIOACCUMULATION IN BLUE CRAB (CALLINECTES AMNICOLA) TISSUE FROM SEDIMENT IN ELECHI CREEK, RIVERS STATE, NIGERIA

Abstract This paper assessed the hazardous metal concentrations and bioconcentration in blue crab (Callinectes Amnicola) from sediment in Elechi Creek, Niger Delta. Sampling occurred at three distinct stations: Station 1 (ST1), a sand-fill area with limited tidal influence; Station 2 (ST2), near a sawmill; and Station 3 (ST3), downstream with stormwater inflows. Monthly collections of sediment, water, and crab tissue were conducted over six months, with metals analyzed via Atomic Absorption Spectrophotometry. Results showed notable spatial variations in metal levels. ST3 recorded the highest concentrations, with Fe at 35.8 ± 8.9 mg/L, Zn at 11.9 ± 3.1 mg/L, Cd at 0.06 ± 0.03 mg/L, and Cu at 114.1 ± 65.0 mg/L in surface water, while sediment levels included Fe at 161.1 ± 27.3 mg/kg and Cu at 425.1 ± 22.4 mg/kg. Bioaccumulation factors (BAF) and bioconcentration factors (BCF) indicated high metal uptake in crabs, especially for Zn and Fe; the BAF values were found to be 13.8571 mg/kg for Zn and 1.1955 mg/kg for Fe at ST3, hence showing higher bioavailability at this location. These results confirmed high levels of metals and accumulating trends in ST3, which might reflect some of the environmental impacts due to localized activities. Overall, this study is an indication of the fact that regular monitoring in the Niger Delta is unavoidable to reduce metal accumulation hazards both to aquatic ecosystems and public health. Keywords: Metal bioaccumulation, Callinectes amnicola, Niger Delta, Contamination