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AN IN VITRO GASTROINTESTINAL METHOD TO ESTIMATE BIOAVAILABLE ARSENIC IN CONTAMINATED SOILS AND SOLID MEDIA. (R825410)
Citation:
Rodriguez, R. R., N. T. Basta, S. W. Casteel, AND L. W. Pace. AN IN VITRO GASTROINTESTINAL METHOD TO ESTIMATE BIOAVAILABLE ARSENIC IN CONTAMINATED SOILS AND SOLID MEDIA. (R825410). ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 33:642-649, (1999).
Description:
A method was developed to simulate the human gastrointestinal environment and
to estimate bioavailability of arsenic in contaminated soil and solid media. In
this in vitro gastrointestinal (IVG) method, arsenic is sequentially extracted
from contaminated soil with simulated gastric and intestinal solutions. A
modified IVG-AB method, where iron hydroxide gel is used to simulate the
absorption of arsenic, was also evaluated. Fifteen contaminated soils collected
from mining/smelter sites ranging from 401 to 17 460 mg As
kg-1 were analyzed. In vitro results were compared with in
vivo relative bioavailable arsenic (RBA) determined from dosing trials using
immature swine which ranged from 2.7 to 42.8% RBA. Arsenic extracted by the IVG
and IVG-AB methods was not statistically different than RBA arsenic measured by
the in vivo method. Arsenic extracted by the IVG stomach and intestinal phases
was linearly correlated (r = 0.83 and 0.82, respectively) with in vivo
arsenic (P < 0.01). Similarly, the IVG-AB method was linearly
correlated (r = 0.79) with in vivo bioavailable arsenic (P <
0.05). All IVG methods extracted similar amounts of arsenic and provided
estimates of bioavailable As in contaminated media. The IVG method may aid in
the design and cost-effectiveness of remedial strategies of arsenic-contaminated
sites.