Solvent Extraction Coupled with Gas Chromatography for the Analysis of Polycyclic Aromatic Hydrocarbons in Riverine Sediment and Surface Water of Subarnarekha River and Its Tributary, I ndia

Abstract

This study investigated the concentration, source and distribution of 16 polycyclic aromatic hydrocarbons (PAHs) in water and sediment samples collected from 56 sampling sites from town, semi-town and rural areas of Subarnarekha River and its tributary Kharkai River. The sources of contamination in these samples were identified using diagnostic ratio (DR) and principal component analysis (PCA). The concentration of Σ 16 PAHs in water samples ranged from (<Detection Limit)<DL to 26 µg/L and the value of mean±SD was 5.7±8 in Kharkai River and ranged from (<DL) to 33 µg/L and the value of mean±SD was 5.8±6 in Subarnarekha River. The dominance of 3-ring PAHs AC and ACY was found in both rivers. In sediment samples of Kharkai River the concentration of Σ 16 PAHs ranged from (<DL) to 185 ng/g, 100 ng/g and 38 ng/g in town, semi-town and rural areas and the values of mean±SD were 240±225, 100±109 and 40±49, respectively. Almost all 16 PAHs were found in all samples collected from different zones of this river but in town areas the concentration was found higher. In the Subarnarekha riverine sediment the concentration of Σ 16 PAHs was in range of (<DL) to 657 ng/g, (<DL)) to 122 ng/g and (<DL) to 68 ng/g in town, semi-town and rural areas respectively. The concentration of Σ 16 PAHs values were found 359±388, 135±143 and 66±78, in town, semi-town and rural areas respectively. The concentration of all 16 PAHs was found much higher in town areas than in other areas. The concentration of 2, 3 and 4-ring PAHs was dominant in all samples. The ratios of AN/AN+Phen and Flur/Flur+Pye were calculated to allocate the sources of contamination in sediment which indicated the contamination was due to combustion and petrogenicorigin in both river and petrogenic, fuel combustion, coal gas and wood burning was predominant source in surface water of both river. The distribution of PAHs sources was supported by PCA.