Chapman access only Poster
Mining activities mobilize undesired trace metal(oid)s during extraction processes, exposing sediment that is easily transported by wind and rain. The presence of dangerous metal tailings is of great concern because of the implications it can hold on human health. The Red Hill Mine in Tustin is inactive; its surrounding land is entirely residential, potentially exposing residents to traces of arsenic daily.
This experiment examines the effect that rainwater has on arsenic bioaccessibility of Red Hill sediment. Gastric bioaccessibility of arsenic is greatest during periods of extreme dryness, producing an increasing correlation between the number of days since last rain event and concentration of arsenic. Therefore, ingestion of sediment from the Red Hill Mine poses the greatest threat to human health during the consistent absence of rain over time.
Aliquots of a Red Hill sediment sample were rinsed weekly over the period of a month, and left to dry outside, avoiding contamination. Upon the conclusion of a month, all samples underwent a simulated gastric fluid extraction, producing data that shows the likely concentrations of As that can develop within the human body through ingestion of the fine particles. The highest As concentration, 0.1573% As, was present in the sample that remained un-rinsed, which was significantly higher than the sample rinsed on the day of extraction, 0.922% As. Data was analyzed to study both the effect that rinsing has on overall arsenic bioaccessibility, as well as the dangers that homeowners near the Red Hill Mine should be aware of.
Whiteman, Katherine and Kim, Christopher S., "Arsenic Bioaccessibility as a Function of Rainfall Exposure and Time in Mining-Impacted Sediments" (2014). Student Research Day Abstracts and Posters. 59.