Distribution, sources and potential toxicological significance of polycyclic aromatic hydrocarbons (PAHs) in the south west coast of Kerala, India

Abstract

To assess the potential eco-risk of PAHs along the study sites (Site1 – characterized by tourist influx and a religious pilgrimage centre resulting in domestic and organic pollution and massive foot traffic. Site 2 – Neendakara characterized by oil pollution since it is a fishing harbour and port with large scale motor boat / trawler traffic. Site 3 –characterized by inorganic pollution of heavy metals, trace metals, polycyclic aromatic hydrocarbons and organochlorins due to discharge of effluents from KMML Titanium dioxide industrial factory. Site 4 –control site since it is presumed to be near pristine being post tsunami and lacking any industrial / agricultural enterprise in the vicinity. The concentrations of N, B (a) A, Fl, ACN, and Ph cases were higher than effects range low (ERL) values, lower than the effects range median (ERM) values, except for Naphthalene and Acenaphthene. At site 2, the sampling areas are found to be stagnant with limited water circulation. Woefully, without attaining any pre-treatment on the issue, the regional industries and shipping harbor are still discharging their wastes into the area, resulting in high ∑ PAH concentration. An alarming fallout of the study is that site 4 also recorded appreciable concentrations of PAHs in the sediment, though it was found negligible in the water column. These results indicated that pessimistic eco-risks are likely to occur, although with a likelihood of 50% effects in this area. However, the remaining compounds were recorded below ERL values, which revealed the low risk of biological impairments. The study has disclosed various concentrations of PAH pollutants of low, moderate, and very high levels from the study sites signaling, effective sustainable management measures, and as a first step for long-term goals, the evaluation of water and sediments along the Kerala coastal ecosystem is recommended.