Concentration (fg/kg) of radioactive isotope Thorium-230 (230Th) in the Beaufort Sea at 3 stations in 2007 and at 4 stations in 2009

The dataset consists of 230Th concentrations (fg/kg seawater) measured in the Beaufort Sea at three stations in 2007 (Sept 22-Oct 15) and four stations in 2009 (Aug 27 - Sep 12). 20L samples were collected and quickly filtered through an Acropak cartridge (0.45 um). The samples were then acidified to pH 2 with concentrated HCl and spiked with pre-weighed quantities of 229Th and FeCl3. Acidified samples were left to equilibrate for 12 to 24 hours and their pH adjusted to 8-9 to precipitate Fe hydroxide and scavenge 230Th and 229Th. The precipitates were let to settle tover 12 to 24 hours and recovered by suction with a peristaltic pump and centrifugation into a 50 ml centrifuge tube for transport to UBC where they were measured on a Element II ICP-MS. The 2007 station locations were: KC500 (71°05'N, 134°22'W, 6 samples at 6 depths), KC2000 (71°44'N, 135°30'W, 12 samples at 12 depths), and KC2700 (72°28'N, 136°56'W, 12 samples at 12 depths). The 2009 station locations were: L1 (71°06'N, 139°10'W, 12 samples at 12 depths), L2 (74°30'N, 137°00'W, 12 samples at 12 depths), L3 (75°17'N, 137°20'W, 12 samples at 12 depths), and L1.1 (72°31'N, 136°48'W, 12 samples at 12 depths).