Concentration and exposure profiles of polycyclic aromatic hydrocarbons (PAHs) in groundwater of commercial site at a terai belt of India

Abstract

Polycyclic Aromatic Hydrocarbons (PAHs) are a group of chemicals which belong to the group of persistent organic pollutants (POPs) know for there chemical carcinogenicity. They are released into the environment from anthropogenic sources such as combustion of fossil fuels, refused burning; industrial process and motor vehicle exhaust which results in occurrence of PAH in many parts of environment. The concentrations of groundwater PAHs were measured at commercial site of Gorakhpurduring winters. The samples were extracted with hexane by ultrasonic agitation. The extracts were then fractioned on a silica-gel column and the aromatic fraction was subjected to high pressure liquid chromatography for analysis of 16 priority PAH pollutants specified by environment protection agency (EPA). Mean concentrations of PAHs were found to be 23.21 ng/L. 3-ring, 4-ring and 5-ring PAHs were found to be dominant in the groundwater of Gorakhpurcity having 41%, 19% and 19% of the T-PAH. Univariate Pearson correlation analysis was performed which shows that the sources of all the PAH compounds are somewhat correlated with each other. Use of toxic equivalent factor (TEFs) shows that Ind(123-cd)P contributed the highest carcinogenic exposure equivalent (3.15 ng/L). The levels of PAHs in the groundwater can help in environmental risk assessment of this area.