Study Chiang Mai, Thailand, December 23, 2025 – New evidence shows that domestic dogs may ingest dramatically higher levels of soil than humans, underscoring the need to reassess exposure risks in companion animals.
Understanding how much soil domestic dogs ingest is essential for evaluating their potential exposure to environmental contaminants. In a foundational study published in 1995, Calabrese and Stanek applied a soil tracer-based mass balance method to quantify soil ingestion in a single Irish Setter over three consecutive days. Eight geochemical tracers—Al, Si, Ti, Y, Zr, La, Ce, and Nd—were used to ensure precise estimation.
The analysis showed remarkable consistency across all tracers, indicating a reliable measure of soil intake. The dog consumed an estimated 10–20 g of soil per day, depending on the tracer used. This finding is particularly striking when compared with the soil ingestion rate reported for an “average” child, typically 30–50 mg/day. The dog’s intake was therefore several hundred times higher than that of a child.
Such a high ingestion rate raises broader welfare and environmental health questions. Many domestic animals interact closely with soil—through digging, chewing, grooming, and exploratory behaviors. If soil routinely contains contaminants such as heavy metals, pesticides, or industrial particulates, dogs may represent a previously underrecognized pathway for exposure.
The authors emphasize the importance of expanding research on soil and dust ingestion in domestic animals and wildlife. Their findings point to potential risks not only for canine health but also for understanding environmental toxicology more broadly. This study remains a key reference for researchers assessing ecological exposure pathways and the behavior of companion animals in complex outdoor environments.
Source: Calabrese, E., & Stanek, E. (1995). A dog’s tale: soil ingestion by a canine. Ecotoxicology and Environmental Safety. No DOI was provided in the supplied text.
