Understanding the effect of oil on phytoremediation of PCB co-contamination in transformer oil using Chromolaena odorata

Greenhouse assessment of the effect of oil on Chromolaena odorata ability to remove PCB from soil treated with transformer oil co-contaminated with Aroclor 1260 was done. Plants were transplanted into one kilogram of soil contained in 1 L pots differently containing 100, 200, and 500 ml of transformer oil (T/O), co-contaminated with 100 ppm of Aroclor. Treatments were done in two microcosms; direct contamination and soil cultured method. Measured plant growth parameters showed that C. odorata growth was affected by the different concentrations of oil. Inhibition of plant growth by oil increased with concentrations. At the end of six weeks, plant growth was affected in T/O amended soil. Plants size was increased by 1.4, 0.46 and -1.0% in direct treatment and 17.01, 6.09 and 1.08% in soil culture at the 100, 200 and 500 ppm respectively. Untreated control showed a 43.07% increase. Slight PCB recovery was observed in root tissues of C. odorata but soil PCB was reduced by 66.6, 53.2, 41.5% and 77.3, 74.7, 58.8% at both treatments in their respective concentrations of oil. However, unplanted control was reduced by 21.4 and 16.7% in the two treatments at 66,000 ppm of oil. This study has shown that with improved agronomic practices, there is a possibility of phytoremediation of soil PCB from PCB contained transformer oil contaminated soil using Chromolaena odorata, hence it should be optimized in the field.