INTRODUCTION: Heavy metal soil contamination is a major environmental issue. Elevated heavy metal soil concentrations significantly impact soil, plant and human health. This project was a community-engaged research project, in collaboration with Historic Westside Gardens (HWG), Environmental Protection Agency (EPA), and the Georgia Department of Public Health. The aims of this study were: (1) to assess baseline levels of heavy metal soil concentration levels in urban West Atlanta; and (2) to assess relationships among heavy metal soil concentrations and their bioavailability in the mimicked gastrointestinal environment.
METHODS: 15 urban agricultural and residential sites were sampled in partnership with HWG throughout West Atlanta, using snowball sampling. All soil samples were analyzed for heavy metal concentrations, using x-ray fluorescence (XRF). 38 soil samples ranging from 200 to 1000 ppm Pb concentration were chosen to process the bioavailability experiment using stomach and intestine physiological based extraction tests (PBET). Our team estimated the bioavailable concentrations of eight different heavy metals at each step and the total heavy metal soil concentrations through inductively coupled plasma (ICP).
RESULTS: Some sampling sites had heavy metal soil contamination in urban West Atlanta. Several selected heavy metal concentrations (e.g. arsenic (As) vs. lead (Pb) and Pb vs. zinc (Zn)) had high correlations. Additionally, only Pb and Zn heavy metal soil concentrations had strong correlations with their bioavailablity. The average total bioavailable concentrations of Pb and Zn exceeded the University of Georgia (UGA) risk reduction standard for agricultural soil. This study also found that there were strong correlations between soil concentration of Pb and Zn, analyzed using XRF and ICP. Compared to ICP measurements, XRF measurements tended to overestimate the heavy metal concentrations of As, barium (Ba), cadmium (Cd), chromium (Cr) and nickel (Ni).
CONCLUSION: For Pb, XRF measurements were highly correlated with ICP measurement and soil Pb heavy metal concentration had a strong correlation with Pb bioavailability. This research provided confidence that XRF was a reliable for detecting soil Pb concentrations. This study also highlighted the importance of reporting the total bioavailable concentrations and percentage to make meaningful conclusions about health impacts.
Table of Contents
1. Introduction 1
2. Materials and Methods 10
3. Results 14
4. Discussion 18
5. Conclusion 22
6. Funding 23
7. References 23
8. Tables and Figures 31
9. Appendices 40
About this Master's Thesis
|Committee Chair / Thesis Advisor|
|File download under embargo until 20 May 2021||2019-04-22||File download under embargo until 20 May 2021|