Heavy Metal Pollution in Abu Dhabi Marine Sediments: A Comparative Study across Different Environmental Areas Using Various Pollution Assessment Indices

Coastal pollution in the Arabian Gulf is an emerging issue, driven by both natural processes and human activities such as atmospheric deposition, industrial effluents, discharges from desalination and sewage treatment plants, reclamation and dredging operations, island developments, and oil and gas exploration. To investigate the bottom sediments pollution characteristics and assessments, twenty-two sites were sampled monthly and quarterly in Abu Dhabi’s territorial waters across various ecological categories which includes natural habitats, confined area, nearby public beaches. The samples were analysed for dissolved trace metals, including, Cadmium, Chromium, Copper, Cobalt, Manganese, Nickel, Lead, Zinc, Mercury, and Iron. The concentrations of these metals in the sediment ranged as follows: Cd (0 mg/kg–4.68 mg/kg), Cr (0.19 mg/kg–47.05 mg/kg), Cu (0 mg/kg–71.31 mg/kg), Co (0 mg/kg–6.57 mg/kg), Fe (82.8 mg/kg–18040 mg/kg), Mn (3.06 mg/kg–282.90 mg/kg), Ni (0 mg/kg–34.63 mg/kg), Pb (0 mg/kg–24.37 mg/kg), and Zn (1.58 mg/kg–198.5 mg/kg). Further levels of heavy metal enrichment in the bottom sediments were assessed using the Contamination Factor (CF), Enrichment Factor (EF), Geo-accumulation Index (Igeo), and Pollution Load Index (PLI). The results show that confined area has severe enrichment in Cd, moderate enrichment in Zn and Cu. PLI also confirms Cd in confined areas is >1 which indicates pollution. These accumulation in confined areas, particularly those with heavy anthropogenic activity, highlights a potential environmental risk to marine biota and eventually human health.