i need a scientific researcher

its for a science extension project. I'm researching about polycyclic aromatic hydrocarbons (PAHs) in contaminated soil. I need to come up with a hypothesis and methodology related to this topic. I was considering extraction of the compounds from the soil, or instead comparing the root growth of various plants in various soil which contain PAHs. The experiment must be conducted at my school lab and price is a factor that may limit my ability to perform the experiment. therefore the method should be considerably cheap as well as easy to conduct in a school lab.