Toxic Metal Bioaccumulation and Human Health Risks Assessment of Crabs (Goniopsis Pelii) From a Perturbed Tropical Mangrove Creek in Southern Nigeria

Abstract

Petroleum exploration and other human activities have resulted in the contamination of aquatic ecosystems in the Niger Delta, raising concerns about the safety of aquatic organisms consumed by the local communities. This study assessed the concentrations, spatial distribution, sources and health risk of toxic metals in crabs (Goniopsis pelii) collected from four sampling stations located along the Goi Creek, Rivers State, Nigeria. Ninety-eight adult crabs were collected and the edible tissues analysed for essential and toxic metals using AAS. One-way analysis of variance (ANOVA) was used to evaluate the spatial variation between the stations, while Pearson correlation analysis was used to determine the inter-metal relationships and possible contamination sources. EDI, THQ, HI, CR and TCR were used to assess the potential health risks from consuming the organism. The results showed significant spatial differences (p<0.05) between the concentrations of most of the metals analysed, with stations II and IV showing relatively higher concentrations of the metals than stations I and III. Fe had the highest concentration of the overall metals investigated and ranged from 63.43±5.96 to 147.61±19.63 mg/kg. Cr recorded the highest concentration of carcinogenic metal and positively correlated with Pb, Ni and As, indicating common anthropogenic sources related to petroleum activities. The health risk assessment showed that Cr was the major contributor to both carcinogenic and non-carcinogenic risks, and that children consistently had higher exposure estimates than adults. The calculated HI and TCR exceeded the recommended thresholds, suggesting potential health risks linked to long-term crab consumption. These results show that Goniopsis pelii are effective biomonitors of metal contamination in aquatic ecosystems and that petroleum derived pollutants have significantly impacted on the safety of seafood and the environmental quality of this ecologically important mangrove ecosystem. The study recommended the need for environmental remediation and regular monitoring of the aquatic organisms.