Hair analysis in sled dogs (Canis lupus familiaris) illustrates a linkage of mercury exposure along the Yukon River with human subsistence food systems.

The dog has been an important biomedical research model and hair samples from sled dogs could be used as a biomarker of exposure to metals. Hair samples were used as a non-invasive indicator of mercury exposure in sled dogs fed commercial food and traditional village diets. Sled dog populations living in rural New York and Alaska were sampled in 2005 and 2006. Total mercury (THg) content was determined on the entire hair sample in sled dogs from reference sites in North Creek, New York and Salcha Alaska. Both sites fed a commercial feed for high performance dogs and had mean THg levels of 36.6 ng/g for New York sled dogs while Alaskan sled dogs, occasionally supplemented with fish oil showed THg mean of 58.2 ng/g. These THg levels are below levels that are suggested to cause adverse effects and should be considered baseline levels. Yukon River sled dogs had higher THg, ranging from 139 to 15,800 ng/g and showed decreasing mean levels from the delta area to upriver. There were significant differences between THg in the dogs from Russian Mission (10,908.3+/-3028 ng/g), the farthest west village, and Ft. Yukon (1822.4+/-1747 ng/g), the farthest east village. All village dogs along the Yukon had higher THg levels than the THg mean level (657+/-273 ng/g) of hair from ancient dogs of the Seward Peninsula.