As a significant pollutant in almost all household air, I chose carcinogenic benzene to focus on in my experiment. This poisonous chemical is prevalently emitted from a long list of domestic products including furniture wax, paint, glues, newspapers, and many others. Due to its toxicity, benzene concentrations need to be kept as small as possible. The purpose of my research project was to determine whether bacteria that are capable of degrading benzene in the soil can heighten a plant's ability to remove volatile benzene from the air. In addition, I wanted to investigate the path of benzene and other volatile organic compounds, or VOCs, throughout the plant.

In the procedural aspect of my experiment, Spathiphyllum petite plants, known to remediate household VOCs, were exposed to two different types of soil bacteria species. As a result, two experimental groups and one control group were established. The first experimental group included potted plants with Pseudomonas putida, a model benzene degrader, growing in their rhizosphere.

The second contained plants with Rhizobium leguminosarum, a bacterial species not known to decompose benzene. Finally, the control consisted of a plant cultivated in the absence of any soil bacteria. After sealing the pots, a plant from each group was simultaneously placed in 3 separate, 40-liter boxes. 5 microliters of liquid benzene were pipetted into the boxes, which, according to a number of trials and calculations, represented 50 to 52 parts per million (ppm) of total aromatic hydrocarbons when fully volatilized. After an hour, the hydrocarbon concentration of each box was measured using benzene gas detector tubes and a sampling pump. This process was then repeated twice more with a new plant-soil complex in each condition.

After experimentation, the average results for these trials show that the control group removed 20 ppm, the R. leguminosarum experimental group removed 18 ppm, and the P. putida experimental group removed 26 ppm of aromatic hydrocarbons. This data suggests that the VOCs were absorbed by the plants and translocated to the rhizosphere where the P. putida played a role in degrading the pollutants. These data also foster the idea that P. putida amplified the plants' ability to uptake VOCs from the air and can help keep volatile concentrations of harmful gases minimal.