Enhancing dissipation of aroclor 1248 (PCB) using substrate amendment in rhizosphere soil

Area of Science:

• Environmental Science
• Soil Science
• Bioremediation

Background:

• Polychlorinated biphenyls (PCBs) are persistent organic pollutants.
• Previous studies show certain plants and soil amendments can enhance PCB degradation.

Purpose of the Study:

• To investigate if combining soil amendments with specific crops further enhances PCB dissipation compared to planting alone.
• To evaluate the efficacy of biphenyl, pine needles, and orange peels as soil amendments.
• To assess the impact of flat pea, reed canarygrass, and burr medic on PCB removal.

Main Methods:

• Laboratory microcosms were used to study Aroclor 1248 (PCB) contaminated soils.
• Soils were amended with biphenyl, pine needles, or orange peels.
• Microcosms were planted with flat pea, reed canarygrass, or burr medic.
• PCB concentrations and bacterial populations were monitored over approximately 100 days.

Main Results:

• Planting alone reduced PCB levels, with reed canarygrass showing the most significant dissipation.
• Soil amendments alone, particularly orange peels and biphenyl, enhanced PCB removal.
• Combinations of amendments and planting generally improved PCB dissipation, except for biphenyl with burr medic.
• Bacterial populations increased with orange peel and biphenyl amendments, but decreased with biphenyl and burr medic combined.

Conclusions:

• Combined soil amendment and crop planting can enhance PCB dissipation more effectively than either treatment alone.
• The choice of amendment and plant species is crucial for optimizing bioremediation strategies.
• Further research is needed to understand the synergistic effects and microbial responses in complex soil matrices.