ASSESSMENT OF POLYCYCLIC AROMATIC HYDROCARBON CONCENTRATIONS IN ENVIRONMENTAL AND BIOTA SAMPLES FROM AZUABIE AND OKUJAGU CREEKS, UPPER BONNY ESTUARY, NIGERIA

Polycyclic aromatic hydrocarbons are persistent organic pollutants that are detrimental to the environment, wildlife and public health. In this research, the concentrations of PAH were evaluated in surface water, sediment and aquatic organisms from Azuabie and Okujagu Creeks of the Upper Bonny Estuary, Nigeria. Sample collection was done bimonthly from August 2023 to June 2024 from four locations, two from each of the Creeks. Both environmental and biota samples were collected using standard research techniques. Modified USEPA Method 522 was adopted for PAH analyses in the samples. The results obtained were analysed using appropriate statistical tools. PAH results in sediment samples ranged from 0.18±0.08 – 18.38±10.37ppm and 0.21±0.01 –26.44±12.25ppm at Azuabie and Okujagu respectively. The higher values were recorded in August, 2023. There were no significant differences between location but there were differences by time. PAH results in surface water samples ranged from 0.16±0.00 – 23.81±18.05ppm and 0.16±0.00 –26.44±12.25ppm at Azuabie and Okujagu respectively. There were no significant differences by location; August 2023 values were significantly higher than those recorded in other months. PAH values in oysters ranged from 0.11±0.007 – 6.34±0.49ppm and 0.17±0.007 – 5.06±0.69ppm at Azuabie and Okujagu respectively. There were no significant differences between location and time. PAH values in periwinkles ranged from 0.22±0.02 – 9.43±1.90ppm and 0.18±0.007 –8.38±0.32ppm at Azuabie and Okujagu respectively. Study locations did not vary significantly but time did. The highest concentrations of the PAH constituents included those of Acenaphthene of 5.715ppm, Naphthalene 4.7ppm and Dibenz(a,h)anthracene of 3.985ppm in both surface water and sediment samples at Okujagu in August 2023. At Azuabie, Benzo[a]pyrene had a concentration of 6.595ppm while sediment had 4.12ppm for Dibenz(a,h)anthracene in August 2023. Biota samples had lower values. For instance, in August 2023, Fluorene had the highest value of 0.9ppm at Azuabie and 0.63ppm at Okujagu in oysters; in periwinkles, Fluorene recorded 1.01ppm at Okujagu, while Benzo[a]pyrene had 1.2ppm at Azuabie. Some of the PAH values obtained in the samples exceeded the USEPA and WHO permissible limits. Thus, urgent measures should be taken towards environmental restoration and food security. This research has revealed varying levels of PAH contamination of surface water, sediment and biota (periwinkles and oysters) samples from locations on the Azuabie and Okujagu Creeks, Upper Bonny Estuary, Nigeria. Preventive measures should therefore be taken to prevent continued pollution while aiding the recovery of both creeks. Measures should also be taken to ensure food safety among the population.