This work provides a novel data set on accumulations of both anthropogenic (Cs-137, Pu-238, Pu239+240, Am-241) and natural (Pb-210, Ra-226, Th-232) radionuclides and an element (K). Sampling of soils and lake sediments was accomplished in 1999 during Tundra Northwest (TNW-99) international expedition to a remote region of the Canadian Arctic. The sediment ages and sedimentation rates were determined. The obtained results overall indicated a high geographical diversity of contamination levels and trends. Accumulation rates were also differential, and a sediment focusing contribution was distinctly visible. Radioactive pollution was found to be lower relative to temperate counterparts. The activity ratios of anthropogenic radionuclides corresponded to global fallout as a prevailing source in the entire examined area. The post-Chernobyl radiocaesium was observed for the westernmost lake only. The elevated level of Cs-137 and Pu239+240 in the topmost sediment at the northern and eastern Arctic Archipelago was attributed to recent resuspension and subsequent redistribution of radionuclides.