Bioavailability Measures for Arsenic in Gold Mine Tailings.

Elevated levels of soil arsenic (As) due to anthropogenic activities have resulted in sites that pose potential health hazards to human populations. The primary risk pathway of concern is incidental soil ingestion, particularly with children. Assessment of risk by the use of total soil As is insufficient and can be misleading due to the wide range of soil properties that control the bioavailability of As. The aim of the current study is to measure the bioavailable fraction of As in gold mine tailings from California. Twenty-five samples were collected with total As ranging from 15.3 to 12,095 mg/kg As. The OSU in vitro method of Basta et al. (2007) and the SBRC method of Juhasz et al. (2009) were used to measure the bioaccessibility of As in the samples. Gatric extractable (GE) As in the OSU-IVG ranged from <2% to 9.3% with a mean of 4.2% and the SBRC GE ranged from <2% to 14.4% with a mean of 3.6%. In vitro as well as other soil extraction results were compared with swine relative bioavailbility (RBA) for six of the twenty-five samples.