Summary — Nucleus colonies (nucs) of = 4 500 honey bees (Apis mellifera L) were evaluated as an alternative to full-size colonies for monitoring pollution impacts. Fifty nucs were deployed at 5 sites along a transect on Vashon Island, Washington. This provided a gradient of exposure to arsenic and cadmium from industrial sources. After 40 d, statistically significant differences were observed among sites for mean mass and numbers of bees (P ≤ 0.01), honey yield (P ≤ 0.07), and arsenic and cadmium content of forager bees (P ≤ 0.001). These findings are discussed in terms of exposure to heavy metals and observed changes in colony dynamics, especially brood rearing and hoarding of pollen, nectar, and honey.