Identification and Quantification of Polycyclic Aromatic Hydrocarbons in Otamiri River Owerri Southeast Nigeria

Abstract

The present study evaluates the Identification and Quantification of polycyclic aromatic Hydrocarbons in Otamiri River. Water samples were collected from Otamiri River and analyzed for polycyclic aromatic hydrocarbons (PAHs). Samples were collected from various strategic sampling points from Otamiri River: Abattoir/Shoprite Residence Point 1 (sampling point 1), Abattoir/Shoprite Residence 2 (sampling point 2), Nekede/Ihiagwa Bridge 1 (sampling point 3), and Nekede/Ihiagwa Bridge 2 (sampling point 4). The Global Positioning System (GPS) was utilized to locate the coordinates of the sampling points. The analysis of polycyclic aromatic hydrocarbons (PAHs) was performed using a BUCK M910 Gas Chromatograph equipped with an Electron Capture Detector (ECD). A RESTEK MXT-1 column (15 m × 250 µm × 0.15 µm) was employed for the separation. The injector temperature was set to 280°C, with a splitless injection of 2 µL of sample, and a linear velocity of 30 cm/s. Helium 5.0 served as the carrier gas, flowing at a rate of 40 ml/min. The oven was initially maintained at 200°C, then ramped to 330°C at a rate of 30°C per minute, and held at that temperature for 5 minutes. The detector operated at 320°C. PAHs were quantified by calculating the ratio of the area-to-mass of the internal standard to the area of the identified compounds. Abattoir/Shoprite Residence sampling point 1 recorded 3.920 mg/ml, Abattoir/Shoprite Residence 2 sampling point 2 recorded 7.749 mg/ml, Nekede/Ihiagwa Bridge 1 sampling point 3 recorded 3.841 mg/mL, and Nekede/Ihiagwa Bridge 2 sampling point 4 recorded 5.422 mg/ml. The total PAH concentrations in the Otamiri River are consistently above the Federal Ministry of Environment (FMEnv) standard of 1.845 mg/mL which suggests a high level of PAH pollution in the Otamiri water, which should be a serious public health concern. High PAH concentrations can harm on aquatic ecosystems, other animals and humans consuming the water.