This page is referenced by:

• 1 2020-05-06T00:39:26+00:00 Michaela Montgomery 5 plain 2020-05-08T23:58:09+00:00

  
  Investigating the Impact of Simulated Rain Events and Aging on Arsenic Bioaccessibility in Mine Waste

  Overview: Sediments from abandoned mines can contain trace amounts of arsenic which humans can be exposed to through incidental inhalation. I found that the amount of arsenic accessible to the human body from the mine sediment decreased after a rain simulation and then increased during a 1-year simulated dry period with fluctuating temperature and humidity. 
  
  Abstract: There is an abundance of abandoned precious metal mines throughout California that pose a potential environmental and health risk to the surrounding areas, especially when the mines are located near residential, urban neighborhoods. The residents who live near the Red Hill Mercury Mine in Tustin, CA, have an increased risk of exposure to mine waste that is enriched in residual trace metal(loid)s. Since arsenic (As) is a common elevated residual trace metalloid in mine waste, the As bioaccessibility of the mine waste samples collected from the Red Hill Mine was studied to determine the initial risk of exposure using the ingestible size fraction (>250 micrometers). The purpose of the study was to investigate the direct influences of rain exposure, temperature, and humidity on the As bioaccessibility of the samples through time. 
       Rain exposure (rinsing) led to a relative decrease in As bioaccessibility (ranging from 13-39% reduction). Following rinsing, the influence of temperature and humidity through time was investigated by exposing the samples to accelerated (12x) wetting/drying conditions in an environmental chamber that simulated actual temperature and humidity conditions (16.1-27.8°C, 36-95%) from October 2017 near the Red Hill Mine. Through bi-monthly simulated gastric fluid extractions, the As bioaccessibility was evaluated over a simulated year period. There was a significant decrease in As bioaccessibility around three “months” and then a gradual increase in As bioaccessibility up to one “year”. Due to this initial decrease in As bioaccessibility, it is recommended to more closely investigate the changes in As bioaccessibility from zero to six “months” at the 12x accelerated temperature and humidity cycle. Additional planned experiments include running 12x, 8x, and 4x accelerated temperature and humidity cycles to examine the effect of acceleration rate of the cycle on the As bioaccessibility and determine the accuracy of the simulated aging.
  
  Zoom Link