A dog's tale: soil ingestion by a canine.

A single Irish Setter pet dog had its soil ingestion behavior quantitatively estimated on 3 consecutive days via a soil tracer-based mass-balance methodology. The results indicated a high agreement among the eight tracers (Al, Si, Ti, Y, Zr, La, Ce, and Nd) employed to estimate soil ingestion. The estimated daily soil ingestion rate ranged from approximately 10 to 20 g/day depending on the tracer. This represents a value far exceeding soil ingestion reported by an "average" child (ranging from 30 to 50 mg/day). The several hundred-fold higher soil ingestion rate in this dog compared to soil ingestion by an average child suggests the need to evaluate more fully soil and dust ingestion in domestic animals and wildlife especially with respect to potential exposure to contaminants in soil.