Seasonal variation of polycyclic aromatic hydrocarbon (pah) contamination in crassostrea tulipa (oysters) and sediments in three Ghanaian Coastal Ecosystems

Abstract

Background and Objective: Polycyclic aromatic hydrocarbons have received considerable attention as environmental organic pollutant in many continents such as Africa, Europe and Asia. Many polycyclic aromatic hydrocarbon compounds have been identified and quantified in virtually all segment of the environment due to their carcinogenicity, mutagenicity and cytotoxicity at very low concentrations. The objective of study was to look at the seasonal levels of polycyclic aromatic hydrocarbons in sediments and Crassostrea tulipa (oysters) (bio-indicator) in three water bodies from three coastal ecosystems in Ghana and also assessed the risk involved in their exposure. Materials and Methods: Two hundred and seventy oysters and eighty four sediments samples were taken for the two seasons (dry and wet season) from three coastal water bodies at Narkwa, Ada and Anyanui and extracted simultaneously by solvent-solid and Soxhlet extraction. The extracts were analyzed for sixteen polycyclic aromatic hydrocarbons using the Agilent 6890N GC-FID/MS. One and 2-way ANOVA and SPSS were employed for the data and statistical analysis. Results: The mean total polycyclic aromatic hydrocarbons levels in oysters from these sites ranged from 66.85-168.59 and 226.24-359.97 µg kgG1 in the dry and wet seasons, respectively. Elevated carcinogenic and mutagenic risks (> unit risk of 1×10G5) were associated with the ingestion of oysters from these sites especially for the wet season. The mean total polycyclic aromatic hydrocarbons concentrations in sediments from the three sites also ranged from 78.82-108 and 72.35-136.35 µg kgG1 for the dry and wet seasons, respectively. ANOVA conducted at 95% CL showed no statistical significant difference between the sites (p = 0.905) and also between seasons (p = 0.112) for polycyclic aromatic hydrocarbons levels in oysters. Also, polycyclic aromatic hydrocarbons in sediments were statistically found to be seasonal dependent (p = 0.007) but not site dependent (p = 0.078). The water bodies from the sites of sampling were polluted since the oysters used as bio-indicators recorded elevated polycyclic aromatic hydrocarbons levels. Conclusion: Patrons are advised to minimize their consumptions of oysters and exposure to contaminated sediments from these sites in order to minimize the health effect associated with environmental polycyclic aromatic hydrocarbons