Determination of Phytotreatment of Polychlorinated Biphenyls Contaminated Soil

Abstract

Chromolaena odorata propagated by stem cuttings and grown for six weeks in the greenhouse ability to thrive in soil containing various concentrations of Polychlorinated biphenyl (PCB) congeners found in Aroclor 1254, and to possibly decontaminate such soil under greenhouse conditions was the paramount objective of this study. PCBs are a family of compounds produced commercially by direct chlorination of biphenyls. In 1L pots, Chromolaena odorata plants were transplanted into soil with 100, 200, and 500 ppm Aroclor. Every day, the trials were watered to a moisture field capacity of 70%. At harvest, parameters such as the number of fully developed leaves per plant, shoot length, leaf chlorophyll content, and root length were measured. PCB was not phytotoxic to the growth of C. odorata, although plants in the 500 ppm treatment only showed a reduction in growth after the sixth week. The percentage increases in plant height for the 100, 200, and 500 ppm treatments were 45.9, 39.4, and 40.0, respectively. Leaf numbers, root length, and leaf chlorophyll content all showed declines. The control sample showed a 48.3% increase in plant height, which was not significantly different from the treated samples, indicating that C. odorata could tolerate such high PCB concentrations and be utilized to remediate polluted soil. The average total PCB absorbed by the C. odorata plant was 6.40 to 64.60 ppm per kilogram of soil, resulting in PCB absorption percentages of 0.03 to 17.03 percent per kilogram of contaminated soil. PCBs were predominantly identified in plant root tissues, with Bioaccumulation Factors ranging from 0.006-0.38. As the concentration of the chemical rises, so does the amount of PCB absorbed by the plant. C. odorata could be a good candidate plant for phytoextraction of PCB from a PCB-contaminated soil if these high BAF are maintained.