BIOAVAILABILITY OF ARSENIC IN SOIL AND HOUSE-DUST IMPACTED BY SMELTERACTIVITIES FOLLOWING ORAL-ADMINISTRATION IN CYNOMOLGUS MONKEYS

This study was conducted to determine the extent of arsenic (As) absor ption from soil and house dust impacted by smelter activities near Ana conda, Montana. Female cynomolgus monkeys were given a single oral adm inistration via gelatin capsules of soil (0.62 mg As/kg body wt) or ho use dust (0.26 mg As/kg body wt), or soluble sodium arsenate by the ga vage or intravenous route of administration (0.62 mg As/kg body wt) in a crossover design with a minimum washout period of 14 days. Urine, f eces, and cage rinse were collected at 24-hr intervals for 168 hr. Blo od was collected at specified time points and area under the curves (A UCs) was determined. Arsenic concentrations for the first 120 hr, repr esenting elimination of greater than 94% of the total administered dos e for the three oral treatment groups, were < 0.021 to 4.68 mu g/ml fo r the urine and < 0.24 to 31.1 mu g/g for the feces. In general, peak concentrations of As in the urine and feces were obtained during the c ollection intervals of 0-24 and 24-72 hr, respectively. The main pathw ay for excretion of As for the intravenous and gavage groups was in th e urine, whereas for the soil and dust groups, it was in the feces. Me an absolute percentage bioavailability values based on urinary excreti on data were 68, 19, and 14% for the gavage, house dust, and soil trea tments, respectively, after normalization of the intravenous As recove ry data to 100%. Corresponding absolute bioavailability values based o n blood were 91, 10, and 11%. The bioavailability of soil and house du st As relative to soluble As (by gavage) was between 10 and 30%, depen ding upon whether urinary or blood values were used. These findings su ggest that risks associated with the ingestion of As in soil or dust w ill be reduced compared to ingestion of comparable quantities of As in drinking water. (C) 1995 Society of Toxicology.