Occurrence, Sources and Environmental Health Risk Assessment of Polycyclic Aromatic Hydrocarbons in Agricultural and Industrial Effluent Discharges in Wadi El Bey (Tunisia)

Persistent Organic Pollutants (POPs) such as polycyclic aromatic hydrocarbons (PAHs) are of great concern due to their persistence, bioaccumulation and toxic properties. The occurrence, source and ecological risk assessment of 26 polycyclic aromatic hydrocarbons in industrial and agricultural effluents affecting the Wadi El Bey watershed were investigated by means of gas chromatographic/mass spectrometric analysis (GC/MS). Total PAHs (Σ 26 PAH) ranged from 1.21 to 91.7 μg/L. The 4 and 5-ring compounds were the principal PAHs detected in most of the 5 sites examined. Diagnostic concentration ratios and molecular indices were performed to identify the PAH sources. Results show that PAHs could originate from petrogenic, pyrolytic and mixed sources. According to the eco-toxicological assessment, the potential risk associated to PAHs affecting agricultural and industrial effluents of Wadi El Bey Watershed ranged from moderate to high for aquatic ecosystem and human health. The Toxic Equivalency Factor (TEF) approach indicated that benzo (a) pyrene and benzo (a) anthracene were the principal responsible for carcinogenic power of samples.