Priority Polycyclic Aromatic Hydrocarbons (PAHs): Distribution, Possible Sources and Toxicity Equivalency in Urban Drains

Abstract

Wastewater from urban areas constitutes one of the major sources of pollutants contributed to aquatic ecosystem. This study was carried out to elucidate the occurrence and possible source of US Environmental Protection Agency identified 16 priority polycyclic aromatic hydrocarbons (PAHs) in water and sediments from the urban wastewater drains in Delhi, India. A total 60 samples (water and sediment) collected during year 2011-2012, and analyzed the following USEPA methods. Water and sediment samples were extracted using liquid-liquid and ultrasonication techniques, respectively. Glass column chromatography with activated silica was used for sample extracts clean-up, followed by quantification on HPLC equipped with diode array detector at 254 nm wavelength using mixture of acetonitrule and water as mobile phase. Concentrations of total 16 PAHs ( 16PAHs) in all drain water samples ranged from 0.29-35.22 μg/L (mean ± SD, 10.83 ± 10.66 μg/L), predominated by two-and three -ring PAHs. The 16PAHs concentrations in all collected sediments ranged between 220-19321 μg/kg (mean±SD, 5574 ± 6820 μg/kg) dry weights. High molecular weight PAHs (≥4-ring PAHs) were dominant in sediment samples. Benzo(a)pyrene equivalent (BaPeq), a relative carcinogenic potential to the corresponding PAHs to BaP was estimated and presented. A selected number of concentration ratios of specific PAHs compounds were calculated and used to diagnose the possible sources of PAHs contamination. The diagnostic ratios reflected pyrogenic input from gasoline or diesel powered vehicular emissions as the major source of PAHs. The levels of PAHs observed in water and sediments were compared with similar studies undertaken in other regions of the world.

Primary Sources of Polycyclic Aromatic Hydrocarbons to Streambed Sediment in Great Lakes Tributaries Using Multiple Lines of Evidence

“…This point was demonstrated using mass fractions analysis and is further supported by simply comparing PAH concentrations from the present study with concentrations in areas where coal‐tar sealants are not used (i.e., outside of the eastern and central United States and Canada). Compared with a ΣPAH 16 mean of 13 300 µg/kg and maximum of 196 000 µg/kg for the present study, studies of urban streams, canals, drains, and lakes in Portland (OR, USA; Yanagida et al 2012), Sydney (Australia; Nguyen et al 2014), Delhi (India; Kumar et al 2016), Beijing (China; Shen et al 2009), Shanghai (China; Yang et al 2018), and Bangkok (Thailand; Boonyatumanond et al 2006) reported mean ΣPAH 16+ concentrations of 663 to 5570 µg/kg (Figure 9). The maximum ΣPAH 16+ concentrations in these studies were all <9000 µg/kg, with the exception of Delhi storm drain sediments, which had a maximum of 19 300 µg/kg.…”

“…bar = mean; whisker = maximum. a Kumar et al 2016; b Shen et al 2009; c Boonyatumanond et al 2006; d Nguyen et al 2014; e Yang et al 2018; f Yanagida et al 2012.…”

Polycyclic Aromatic Hydrocarbons in Soil and Vegetation of Niger Delta, Nigeria: Ecological Risk Assessment

“…Te existence of diferent homologs of PAHs (PAHs with a number of aromatic rings) and PAHs with diferent molecular weights in the environment suggests their likely origin or sources [72][73][74][75][76][77].…”