Student Summer Research: Soils Part 2!

Student Summer Research: Soils Part 2!

This week’s blog post features two research projects from students during our summer program. Both of these students studied metal concentrations in soils, specifically lead.

 

First Research Project

Introduction
The first project began with a curiosity of lead levels in the soil surrounding a school in southwest Illinois. The student surveyed the area for potential areas of interest and sampling sites. The research question they developed was, how does the lead concentration vary throughout the area around the school. They hypothesized that the highest concentration of lead would be found near the school parking lot entrance near the roadway. They believed vehicles might be introducing lead to the soils in this vicinity.

Materials and Methods
Drone
T-Probe
Shovel
Digital Camera
X-ray fluorescence (XRF)

Sites were selected based on aerial imagery from drone flight around the area. After site selection, the student used a T-probe and a trowel to collect soil samples at various depths from each site. Samples were stored and labeled in bags accordingly. With the help of a graduate assistant, the samples were then measured for lead concentration using the XRF. Concentration results were organized and stored to be prepared for analysis.

Results and Conclusions

Figure 1. Percentage of lead levels at each site. For reference, 10,000 ppm is equal to 1%.

All sites were within a safe level of lead concentration. According to the U.S. EPA, all of the sites could be used as gardening soil.

Figure 2. EPA recommendations on soil lead concentration and food safety. Image provided by the U.S. EPA.

The student’s hypothesis was correct and they found that the site with the highest concentrations was at the entrance of the parking lot just off the roadway. The second highest concentration was just off the parking lot near a tree line. It was suggested that these higher concentrations could be a result of frequent vehicle travel or because of the site’s close proximity to a steel mill.

 

Second Research Project

Introduction
Similar to the previous research project, this student’s work focused on lead concentration in soils. Their research question was, how does the level of lead in soils near the school compare to the soils from nearby public parks. This student was interested in the comparison of a school in southwest Illinois and publicly accessible green spaces.

Materials and Methods
Drone
Microsoft Excel
Digital camera
Field journal
X-ray fluorescence (XRF)

This study consisted of 29 sample sites, 20 of which were at the school in southwest Illinois and the remaining nine were from three different public parks in the area. The student used the XRF, with help from a graduate assistant, to find lead concentration in the soil at every sampling site. These data were then curated and stored for data analysis.

Results

Figure 1. Graph of all sample sites and their respective lead levels in parts per million.

Future Work
The student suggested that future research could be done to better understand lead concentrations in this area’s soils. They want to see how these levels could be affecting the surrounding environment and also how to eliminate lead exposure to undetectable levels.