Polycyclic Aromatic Hydrocarbon (PAH) Contents in Plant Tissues in Selected Mangrove Communities

This study was aimed to investigate the Polycyclic Aromatic Hydrocarbon contents in plant tissues in selected mangrove communities. The study was conducted in three mangrove communities in Akwa Ibom State: Iko Town (Eastern Obolo LGA), Okoroutip (Ibeno LGA), and Uta Ewa (Ikot Abasi LGA). Vegetation and soil sampling involved four randomly selected plots per site, each containing three belt transects. A systematic sampling approach was used. The vegetation parameters of Acrostichum aureum plant tissues (roots, stems, and leaves) were taken to laboratory for PAH analysis. Seventeen priority PAHs were analyzed in plant tissues using standard chromatography methods. The study revealed that in the dry season, Acrostichum aureum leaves in Okoroutip had the highest PAHs (24.53 mg/kg), dominated by benzo[j]fluoranthene and 3-methylcholanthrene, while roots were lowest (1.42 mg/kg). In Iko Town, stems accumulated the most PAHs (1.89 mg/kg), and in Uta Ewa, stems were highest (1.95 mg/kg) with lower root levels. During the wet season, PAHs increased, especially in Iko Town leaves (34.26 mg/kg, mainly indeno [1,2,3-cd]pyrene) and Okoroutip leaves (12.35 mg/kg, benzo[j]fluoranthene). Uta Ewa roots showed higher PAHs (5.77 mg/kg) than other tissues. Overall, high-molecular-weight PAHs (4–6 rings) predominated, with leaves and stems as major accumulation sites, showing clear seasonal and site variations. Acrostichum aureum accumulates high levels of PAHs, with tissue-specific and seasonal variations influenced by pollution sources and plant physiology. The species has potential as a bioindicator and accumulator of PAHs, though its effectiveness in active remediation likely depends on microbial associations. Recommendations include continuous monitoring of PAHs in mangrove ecosystems, stronger regulation of petroleum-related activities, use of A. aureum as a bioindicator, exploration of integrated phytoremediation strategies, and public health awareness to reduce exposure through contaminated seafood.