In this work, we use stable Zn and Cu isotopes to identify the sources and timing of the deposition of these metals in a sediment core from Lake Ballinger near Seattle, Washington, USA. The base of the Lake Ballinger core predates settlement in the region, while the upper sections record the effects of atmospheric emissions from a nearby smelter and rapid urbanization of the watershed. δ66Zn and δ65Cu varied by 0.50? and 0.29?, respectively, over the 500 year core record. Isotopic changes were correlated with the presmelter period (?1450 to 1900 with δ66Zn = +0.39? ± 0.09? and δ65Cu = +0.77? ± 0.06?), period of smelter operation (1900 to 1985 with δ66Zn = +0.14 ± 0.06? and δ65Cu = +0.94 ± 0.10?), and postsmelting/stable...
