(PT011) An in vitro gastrointestinal (IVG) method to estimate relative bioavailable cadmium and lead in contaminated soils.
Schroder, J.1, Basta, N.1, Si, J.1, Payton, M.1, Evans, T.2, Casteel, S.2, 1 Oklahoma State University, Stillwater, Oklahoma, United States2 University of Missouri-Columbia, Columbia, Missouri, United States
ABSTRACT- The effect of the dosing vehicle (e.g., dough) on the ability of an in vitro gastrointestinal (IVG) method to predict relative bioavailable Cd and Pb associated with soil ingestion was evaluated. Bioaccessible Cd, determined by the IVG method, was compared with relative bioavailable Cd measured from dosing trials using juvenile swine for 10 soils contaminated with Cd ranging from 23.8 to 465 mg Cd/kg soil. Bioaccessible Pb was compared with relative bioavailable Pb for 18 contaminated soils ranging from 1,270 to 14,200 mg Pb/kg soil. Bioaccessible Cd and Pb were measured in the IVG gastric extraction (GE) and intestinal extraction (IE) solutions. Means for bioaccessible Cd (in parentheses) were GE without dough (63.0%) > IE without dough (39.1%) > GE with dough (38.2%) > IE with dough (12.9%). Mean bioaccessible Pb (in parentheses) were GE without dough (32.2%), GE with dough (23.0%), IE without dough (1.06%), and IE with dough (0.56%). In vivo relative bioavailable Cd ranged from 10.4 to 116% with a mean of 63.4%. Linear relationships between IVG GE without dough (r = 0.86), IVG IE with dough (r = 0.80) and in vivo relative bioavailable Cd were found. In vivo relative bioavailable Pb ranges for different swine tissues (in parentheses) consisted of blood (1 to 87%), liver (0 to 110%), kidney (1 to 124%), and bone (0.04 to 94%). Strong linear relationships between IVG GE Pb with dough (r > 0.76), IVG IE Pb with dough (r > 0.56), and IVG GE Pb without dough (r > 0.81) and in vivo bioavailable Pb as estimated with blood, kidney, liver, and bone were established. The IVG method can be utilized to estimate relative bioavailable Pb, As, and Cd in contaminated soils.
Key words: lead, cadmium, bioavailability, in vitro gastrointestinal (IVG)