Anthropogenic impact on metal concentration in surface water, sediment and Sarotherodon melanotheron (Rüppell, 1852) from Amadi Creek, Rivers State, Nigeria: Implications for ecosystem and public health

Metals are natural components of the biosphere however, above certain concentrations, all metals pose significant risks to aquatic organisms, ecosystems, and human health. This study, conducted from June to August 2023, assessed the concentrations of iron (Fe), lead (Pb), copper (Cu), and chromium (Cr) in surface water, sediment, and blackchin tilapia (Sarotherodon melanotheron) from Amadi Creek, Port Harcourt, Nigeria. Samples were collected monthly from three established stations and analysed for metals using atomic absorption spectrophotometry. The results revealed the presence of all four metals at varying concentrations across stations and matrices, with sediment exhibiting the highest concentrations. For instance, Cr concentrations (mean ± SD) at Station 1 were 4.77±0.26 mg/L (surface water), 9.37±0.22 mg/kg (sediment), and 5.52±0.32 mg/kg (S. melanotheron). In surface water, the values exceeded the respective limits set by the National Environmental Standards and Regulations Enforcement Agency (NESREA) for fisheries cultivation. In sediment, the concentrations of metals across the stations were Fe>Pb>Cu>Cr, values were below the USEPA sediment standards and the “Threshold Effect Concentration” (TEC) of the Consensus-Based Sediment Quality Guideline (CBSQG). The concentrations of metals in S. melanotheron were all below the standards set by the EU, FAO/, and USFDA. In conclusion, the consistent detection, elevated levels, and significant spatial variations in metal concentrations across stations highlight areas requiring targeted remediation, particularly the marine base jetty (Station 1), which appears to be the epicentre of metal pollution. The bioaccumulation of metals in S. melanotheron raises concerns for human health through fish consumption, underscoring the need for stringent environmental monitoring and pollution control measures to mitigate anthropogenic impacts and ensure environmental sustainability in Amadi Creek.