Heavy metal contamination in the Greater Amanzule Wetlands: a public health concern and a threat to seafood provision.

The Greater Amanzule Wetland (GAW) in southwestern Ghana is an ecologically important coastal ecosystem that supports biodiversity, fisheries, and local livelihoods but is increasingly threatened by anthropogenic activities. This study assessed heavy metal contamination in water and seafood species from the GAW and evaluated potential ecological and human health risks. A total of 126 water samples were collected from communities during three sampling periods in 2024 and analysed for cadmium (Cd), copper (Cu), arsenic (As), lead (Pb), nickel (Ni), and mercury (Hg). Thirty-six seafood (36) samples comprising Bagrid catfish (Chrysichthys nigrodigitatus), Blacked-chinned tilapia (Sarotherodon melanotheron), and Black tiger shrimp (Penaeus monodon) were analysed for Cd, Pb, and Hg. Heavy metal pollution index (HPI), heavy metal evaluation index (HEI), principal component analysis (PCA), and bioconcentration factor (BCF) were applied to evaluate contamination patterns, while estimated daily intake (EDI), hazard quotient (HQ), and hazard index (HI) were used to assess potential non-carcinogenic human health risks. The results revealed widespread heavy metal contamination across most sampling communities, with water concentrations generally following the trend As < Hg < Cd < Pb < Ni < Cu. Pollution indices showed moderate to very high contamination in impacted communities, while PCA showed that Cu, Ni, Pb, Cd, As, and Hg contributed substantially to variations in water quality, suggesting mixed anthropogenic and geochemical influences. Health risk assessment showed that estimated daily intake values were below corresponding reference doses and all HQ and HI were below unity, meaning no immediate non-carcinogenic health risks under the evaluated exposure conditions. However, the persistent occurrence of toxic metals highlights potential ecological and public health concerns. The study findings recommend the implementation of integrated wetland management strategies, strengthened regulation of pollution sources, routine monitoring of heavy metal levels in aquatic ecosystems, and increased community awareness on sustainable seafood consumption. Future research should incorporate sediment assessments and long-term studies to better understand contaminant dynamics and potential chronic health implications within wetland-dependent communities.