[Week 3]: An Ideal Site

This week I have been tasked with the rather daunting assignment; designing my research project. Dr. Hamdan was awesome enough to get her hands on some resources so I can become more familiar with ArcGIS but that was the end of my excitement. Dr. Hamdan instructed me to select a site to collect samples from along with defining the methods of collection. These collection sites were already outlined in Dr. Hamdan's previous paper, "Recreational Shooting in Tonto National Forest, AZ: a case study of heavy metal contamination in desert soils" (2016). After reading her paper I was told to evaluate each site while keeping in mind that we have the money for approximately 40 samples. I needed to make a decision considering various factors, defend that decision, then create a sampling method.

I initially began to feel overwhelmed, as this is brand new to me and it felt like I was now presented to climbing a mountain. But if there's one thing I learned from hiking mountains, its that any step forward will get you going and you need to just take it one step at a time. Below is an overview of my research design proposal. Let's see if you can stay awake until the end.

S-STEM Scholar Research Proposal:

Travel of Heavy Metal Contamination from Ammunition Cartridges Downslope in Tonto National Forest, AZ

RJ L. Mabry

Abstract

The objective of this research proposal is to roughly explain the proposed research topic choice, how the research will be conducted, and anticipated findings. This project will analyze the travel of heavy metal contamination within the Tonto National Forest, AZ. This is a continuation of a study initiated in 2016 by Dr. Abeer Hamdan of the physical sciences department at Phoenix College.

 Ammunition contains many heavy metals such as Lead and Antimony (Mozafar et. Al, 2001, pg. 177). While it has been proven that metals can contaminate soils and affect vegetation and wildlife (Peralta,et al. 2001), this phase of research will examine the travel of contamination down slope into ephemeral streams from rainfall.

This project was selected from a desire to observe and familiarize with heavy metal analysis.  As a chemistry major pursuing material sciences, metals are a central point of study. Though a student may not be a declared sustainability major, as a steward of science and a young person it is important to do one’s part and stand on the forefront of ecological progress. The world is seeking alternatives and answers to curb human caused climate change, and it is everyone’s battle to fight (not just sustainability majors). The main objective of this research project is to select a sample site and develop sample collection methods.

Proposed Research Design. In short, this research project will consist of collection soil samples from a preselected site in Tonto National Forest, AZ. The samples will be sent to a lab for analysis or potentially be prepped depending upon availability of equipment. The results will be analyzed most likely by ICP-AES (Li et al., 2001, pg. 1362).  This involves nebulizing the sample as an aerosol with a supporting gas, Argon, through concentric quartz tubes. Induction coils wrapped around the tube produce an oscillating magnetic field which excites ions and electrons in the sample (Tissue, 2001).. The sample then emits a photon as a result which is recorded on a high resolution spectrometer and the corresponding wavelength can indicate specific elements present.

            This is an expensive and complex process that is not feasible for a sophomore at a community college and will therefore be outsourced, though a tour of a similar lab will be organized. The samples may need to be prepped however that will be determined by the research advisor, Dr. Hamdan. Since experimentation is out of the research intern’s control, the independent variable for this project will be the heavy metal concentration in collected soils. The dependent variables will be the location of the sample site accounting for slope and total distance from the shooting range. The results will most likely be evaluated based off of the unequal variance t-test, Welch’s t-test. Further study of these statistical techniques need to be done in order to come to a conclusion. Lastly, a research paper will be written documenting the results.

Selection of a collection site. The first task of designing this research project is selecting a collection site. There are five potential collection sites based off of Dr. Hamdan’s previous studies and the research intern was tasked with selecting a site. An ideal site has a sharp decline into an ephemeral stream over a short distance of land for maximized drainage due to rainfall. Strong drainage would allow for analysis of concentration over a stretch of land due to natural phenomenon. The site would hopefully be located right below a mountain or ridge top which could be used as a control site, as federal regulation asks for a target and berm/backstop. This would minimize the legal likelihood of having lots of contamination at hill tops and peaks, as there needs to be an endpoint for the ammunition. (US Department of Agriculture, 2009, pg. 1). If at all possible, collection would start at the hill top and run parallel to the direction of shooting, yet perpendicular to drainage which collects at a depression or stream.

Due to financial constraints this project has the funds for approximately 40 samples. Because of this constraint, to maximize the ability to collect samples total distance of the site should be minimized. This will also help to avoid variance in results due to factors other than heavy metals travelling downslope in from rain water. Soil would be collected downhill in two mirrored 20 meter long plots of land. These two zones will be one meter wide by 20 meters long. Each zone will be sectioned into 10 one by one meter plots, for a total of 40 plots combined. These two strips would ideally have close to identical downward slopes, to ensure a somewhat similar travel of rain water and therefore, metal contamination. This could potentially create a similar concentration of heavy metals between the two strips as the previous phase of study showed that cartridge litter did not have a significant effect on contamination (Hamdan, 2016, pg. 6). Therefore, by collecting from two similar and parallel zones the research will essentially have two sets of data in order to better confirm or deny the travel of contamination downhill into ephemeral streams.

Superficial Analysis of Prospective Sites. A a cursory evaluation of these sites were performed via Google Earth as ArcGIS is still being learned and the research intern does not have full access to its features yet. Each site was viewed from approximately 1.2 km above ground. The direction of shooting is estimated based on vehicle placement and direction, identifiable berms or backstops, and missing vegetation as ranges tend to have low vegetation growth compared to its adjacent area (Mozafar et. Al. 2001, pg. 177). While this evaluation is not based on concrete data, this will allow the research intern to receive a general overview of site options.

Collection Site 1 (Aerial view 1.7 km above ground)

Site 1. This is the southern-most site and appears to the downstream to the other four sites. The entrance runs northwest and shooting appears to occur south, letting the southern hill act as a berm. The up range area appears to be at the bottom of a large ephemeral stream. It appears to be the most accessible from the highway and consequentially may receive the most shooter activity. However, this could also increase the probability of heavy metals from sources other than ammunition cartridges. There is a clear, very pronounced ephemeral stream downslope and nearby. While the path is very strong downslope, it is unclear whether the angle of elevation is steep enough. Furthermore, judging where the vehicle is parked there is a high chance that some of the contamination could be due to vehicles and an ideal site will provide the most isolation of factors. 

Collection Site 2 (Aerial view 1.1 km above ground)

Site 2. This is just north up the road from Site 1. Its downward slope is eastward with the entrance on the west side. While Site 2 does not have the big pronounced pathway into a large stream, this site has a steeper change in altitude over a shorter distance on its eastern side. There are many small dried streams which appear to have been created from either rainfall or human factors. Instead of one large track, there are about four small streams which lead to a small, narrow yet pronounced stream connecting down to Site 1. This site is still relatively accessible from the highway and it too may receive high shooter activity. What is of interest is that it appears to have a sharp downward slope which is not connected directed to other shooting sites northbound. This would allow for isolation of factors a bit further, and allow for clearer results. However, it is very unclear what direction shooting occurs in as there are multiple location that could be utilized as a berm.

Collection Site 3 (Aerial view 1.3 km above ground)

Site 3. This site appears to have its berm facing southbound and its downward slope heads northeast, with the entrance to the west. While this have a clear downward slope into a small stream, it is unclear if the berm is close to the proposed control site (hill top). Looking at the landscape it appears rain would flow down a small saddle-like area, however it may be a longer stretch farther than 20 meters, the maximum distance for the collection zones. The draw appears to create a clear path of travel for rainfall with identical plotting zones on either side. Visualizing where people tend to park their vehicles though, contamination from tires and exhaust might also mix in with the ammunition during a heavy storm.

Collection Site 4 (Aerial view 1.3 km above ground)

Site 4. This site’s entrance is eastbound and shooting appears to occur westbound. There is a small peak to the northwest and the downward slope occurs northbound from the presumed shooting range. This could be an ideal site if there was a defined ephemeral stream at its base. The hilltop seems to have enough distance from the presumed berm to provide a good control site. The downward slope occurs in such a fashion that collecting samples eastward show a clear change in heavy metal concentration. But there is no clear waterbed nearby and the terrain appears quite rocky and may prevent clear and even collection. Furthermore, considering the direction of the parked vehicle, metal contamination could stem from its tires which would provide more uncertainty in my analysis. 

Site 5 (Aerial view from 2.2 km)

Site 5. This could be an ideal site if this project had much more money and time. There is a large, apparent downward slope into very pronounced stream which appears to have originated solely from rainfall.  Its entrance is from the southwest, as the road travels northeast.  It is the farthest from the highway, and the road is on the other side of the hilltop’s peak in regards to collection. This would help isolate metals from tires and exhaust a bit, as the metal carried by rainwater is separate from the roadway. It is unclear where the berm is located, but it appears southbound considering lack of vegetation. Besides the downward slope being too far from hilltop to stream, the another downside is that there may not have a strong control site due to the suspected shooting traveling towards the peak.

Final Decision. This is a lot to consider and days have been spent evaluting the pros and cons of each site. The above evaluations do not representing the entirety of the considerations but hopefully provide insight. On a personal note, making a decision is better than making none. The selected collection location will be at Site 3. This was chosen due to its clear downward slope, nearby hilltop that could serve at a control site, and an ephemeral stream at its base. While final consultation is needed with Dr. Hamdan, this is my first step towards solidifying my research plan.

This is highly subject to change.

Sample Collection Methods. Samples will be collected with stainless steel spoons or e-tools, depending on access of equipment. The goal is for each sample to contain at least 50g up to one inch deep without pieces of vegetation, large rocks, or trash. While this will not be an exact measurement (scales will not be in the field), these samples will be placed in marked zip lock bags. Notation will include East or West Zone, followed by Site number (e.g. Site 1, Site 2). The control sites of each zone will be notated with as Control instead of Site. The full notation will look something like: “ES1”, “ES2”, “WS1”, “WS2”, “EC”, “WC”, etc.

Concluding Remarks. Everything designed is subject to change. This proposal is based off of introductory knowledge of Geochemistry and guided reading of related publications. Further consultation with research advisor, Dr. Hamdan, will be required. 

Thank you for stopping by and I will see you next week!

RJ

References

Hamdan, Abeer, 2016, “Recreational Shooting in The Tonto National Forest, AZ: a case study of  the heavy metal contamination in desert soils”. Phoenix College.

Li, Xiangdong, Chi-sun Poon, and Pui Sum Liu. (2001). “Heavy metal contamination of urban soils and street dusts in Hong Kong.” Applied Geochemistry 16.11: 1361-1368. https://doi.org/10.1016/S0883-2927(01)00045-2

Mozafar, A., Ruh, R., Klingel, P., Gamper, H., Egli,S., & Frossard, E. (2018). “Effect of heavy metal contaminated shooting rang soils on mycorrhizal colonization of roots and metal uptake by leek”. Environmental monitoring and assessment, 79(2), 177-191. https://doi.org/10.1023/A:1020202801163

Peralta, J., Gardea-Torresdey, J., Tiemann, K. et al. (2001). “Uptake and Effects of Five Heavy Metals on Seed Germination and Plant Growth in Alfalfa (Medicago sativa L.)” Bulletin of Environmental Contamination and Toxicology 66(6): 727-734. https://doi.org/10.1007/s001280069

Tissue, Brian M. (2000).” Inductively- Coupled Plasma (ICP) Excitation Source”. http://www.tissuegroup.chem.vt.edu/chem-ed/spec/atomic/emission/icp.html

US Department of Agriculture (2009), “Recreation Opportunity Guide”. https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5181928.pdf