Analysis of 210Po, 210Bi, and 210Pb in atmospheric and oceanic samples by simultaneously auto-plating 210Po and 210Bi onto a nickel disc

Po-210 and Pb-210 are commonly measured to study particle cycling and particulate organic carbon export (POC) flux from the upper ocean. Bi-210 is a potential oceanographic tracer. However, no convenient and rapid analytical method for Bi-210 has been developed in the marine environment due to its short half-life (5 days). The aims are to study factors influencing the simultaneous auto-plating of Po-210 and Bi-210 onto nickel disc and to develop an effective ship-board procedure for the rapid measurement of Po-210, Bi-210, and Pb-210 at sea. The results suggest that the optimal conditions for auto-deposition of Po-210 and Bi-210 were achieved by using a 25 mm diameter nickel disc in 60 mL acidic solution (pH = 0.5) for 16 hat 25 +/- 1 degrees C. By adding Po-209 and Bi-207 as yield tracers to the sediments, recoveries of Po and Bi were >90%. If Po-210 or Bi-210 were in equilibrium with Pb-210, Po-210 and Bi-210 could also be potential proxies for Pb-210 in sedimentary chronology. The overall recoveries of Po-209 and( 207)Bi were >70% for rainwaters and >60% for seawater samples, respectively, which indicates this analytical procedure is also applicable to marine and atmospheric environments. This method allows the rapid measurement of Bi-210 on a ship and help to obtain its vertical profile or spatial distribution in the marine environment within 1-2 days.