Persistent Organic Pollutant: A Review on the Distribution of Polycyclic Aromatic Hydrocarbons (PAHs) in Aquatic Ecosystem

Polycyclic aromatic hydrocarbons (PAHs) are a class of ubiquitous, carcinogenic and persistent organic pollutants. As persistent contaminants, they do not just pollute the immediate environment where they are released but travel from place to place. They have little degradability and are capable of reacting with other pollutants in the environment to form worse contaminants. It is shown in this work that PAHs are inevitably abundant in the sediment and water bodies as well as in fish. The concentration of PAHs in the aquatic environment could be attributed to the pollutants from the terrestrial ecosystem which eventually finds their way into the water bodies as effluents or run-offs. Sources and route source of some carcinogenic and mutagenic forms of PAHs were also considered and some notable and most dangerous PAHs were also classified in terms of sources. Evidences of bio-accumulation of this carcinogen abound and this poses serious trait to the free existence of living organisms both on land and in water. Combustion of oil, garbage, petroleum and petroleum products should be checkmated so as to reduce the accumulation of PAHs emanating from anthropogenic activities because the major concentration of PAHs in the environment is credited to anthropogenic source. Regular PAHs monitoring in the environment is advised and researchers should invest more energy towards discovering better and low cost effective means of PAHs contaminated air, soil and water remediation.