Throughout the environment, polycyclic aromatic hydrocarbons (PAHS) are created from incomplete combustion, adding to the pollution of the world. Some of these PAHs have been found to be carcinogenic, and efforts have been made to degrade them. They are found in the air and in the soil. However, PAHs are not detectable without HPLC or mass spectrometer, which are not found in everyday situations.

This project is focused on finding a visible bioindicator of phenanthrene, a PAH. Many other bioindicators might absorb PAHs, but according to a previous study, Lepidium sativum will not germinate when there are PAHs in the soil in which they are grown. This project adds to this idea by adding Pseudomonas putida, a PAH-degrading bacteria, to the soil with phenanthrene to see if Lepidium sativum can germinate after Pseudomonas putida supposedly degrades the phenanthrene. Using glass jars to grow the Lepidium sativum, I grew P. putida in BHB broth and glucose, centrifuged it, and added the suspended bacteria in broth without glucose to the soil with phenanthrene. The phenanthrene was added to the soil by dissolving it in acetone.

The germination of L. sativum considerable decreased with the addition of phenanthrene to the soil, but when P. putida was added as well, L. sativum germinated with higher percentages. However, the differences were not quite statistically significant because of the high standard deviation of the triplicate with P. putida and phenanthrene.

In conclusion, L. sativum is mostly likely able to indicate whether medium-high quantities of phenanthrene are present in soil, but further trials need to be repeated with uniform watering conditions. Further research may be done on biomass, growth rates, and higher levels of phenanthrene.