Students collected soil samples in 2013 from over 40 locations (pictured above) across the central portion of the YEW. They analyzed the samples for a range of substances and characteristics related to soil fertility, structure, and biogeochemistry, including phosphorus, magnesium, potassium, calcium, carbon, nitrogen, depth of litter layer, water holding capacity, and respiration rate.
In 2014, students analyzed the samples for metals such as lead, mercury, and arsenic, because these heavy metals can be harmful to plants, animals, and people if found in high concentrations. At this site, they could come from leaking sewer lines, paint scrapings, atmospheric deposition, and the use of contaminated fill. Most of the samples showed slightly elevated levels of heavy metals, as is common for urban soils. However, because soil in the YEW is used primarily for research, and there are minimal human-soil interactions, these high levels do not currently pose a significant health risk.