Concentrations and risks of PCBs in soil contaminated with transformer oil in selected locations in Warri South Local Government Area, Delta State, Nigeria

Abstract

According to the list of persistent organic pollutants (POP), polychlorinated biphenyls (PCBs) are a class of organic substances whose usage has been outlawed in the majority of nations. In addition to been used in paint, flame retardants, plasticizers, and lubricants, they were principally employed in transformers, capacitors, and other industrial purpose. PCBs have been found everywhere over the world because they are capable of being released into the environment through primary and secondary sources, travel over great distances in the atmosphere and are thus persistent. PCBs were examined in soil from area around transformer installations at several sites in Warri South Local Government Area (LGA), Delta State, Nigeria. Using Agilent 6975 GC-MS at three different locations, the evaluation was conducted for both total PCBs and congeners. The soil samples were cleaned with column chromatography using silica gel and hexane as the eluting solvent and extracted with a 1:1 hexane-acetone solution in an ultrasonic bath. With the following results recorded - Ubeji (0.148 ± 0.019 mg/kg), Ogunu (0.531 ± 0.063 mg/kg) and Edjeba (0.415 ± 0.34 mg/kg), the assessment demonstrate that all locations were polluted with PCBs that were below the maximum limit of 2.0 mg/kg as allowed by the United States Toxic Substance Control Act (USTSCA). The total cancer risk calculated in these chosen locations corresponds to Ubeji (5.41×10−7), Ogunu (1.95×10−6) and Edjeba (1.52×10−6). This result showed that all the locations assessed have very low to low cancer risks compared with the value advised by USTSCA.