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

ABSTRACT

210Po and 210Pb are commonly measured to study particle cycling and particulate organic carbon export (POC) flux from the upper ocean. 210Bi is a potential oceanographic tracer. However, no convenient and rapid analytical method for 210Bi 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 210Po and 210Bi onto nickel disc and to develop an effective ship-board procedure for the rapid measurement of 210Po, 210Bi, and 210 Pb at sea. The results suggest that the optimal conditions for auto-deposition of 210Po and 210Bi were achieved by using a 25 mm diameter nickel disc in 60 mL acidic solution (pH = 0.5) for 16 h at 25 ± 1 °C. By adding 209Po and 207Bi as yield tracers to the sediments, recoveries of Po and Bi were >90%. If 210Po or 210Bi were in equilibrium with 210Pb, 210Po and 210Bi could also be potential proxies for 210Pb in sedimentary chronology. The overall recoveries of 209Po and 207Bi 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 210Bi on a ship and help to obtain its vertical profile or spatial distribution in the marine environment within 1-2 days.