Heavy metal contamination in mangrove ecosystems: assessing bioaccumulation in crabs and snails along the Bayelsa Coast, Nigeria

Abstract

Rapid human population growth and industrial activities along coastal areas have intensified anthropogenic contamination in water, sediment and edible fauna, posing public health risks. Mangrove ecosystems act as pollutant sinks, increasing the likelihood of heavy metal accumulation in aquatic organisms. This study examines heavy metal contamination and bioaccumulation in crabs (Callinectes amnicola) and snails (Tympanotonos fuscatus) from mangrove ecosystems along the Bayelsa coast, Nigeria. Water, sediment, crab and snail samples were collected from three stations and analysed using flame atomic absorption spectrophotometry for lead (Pb), cadmium (Cd), nickel (Ni), arsenic (As), zinc (Zn) and copper (Cu). Biota-sediment accumulation factor (BSAF) analyses for crabs revealed significant bioaccumulation of Ni, As and Zn, particularly in highly contaminated stations. The target hazard quotient (THQ) suggested low immediate health risks for human consumers. Ongoing monitoring and pollution control measures are essential to mitigate potential long-term exposure risks and protect public health and ecosystem integrity.