Atmospheric depositional characteristics of beryllium 7 and lead 210 along the southeastern Virginia coast

Abstract

Atmospheric depositional fluxes of 7Be and 210Pb were measured simultaneously in wet‐only and bulk deposition over a 29‐month period (October 1982 through February 1985) in Norfolk, Virginia (36°53′N, 76°18′W). Total precipitation accumulation during 1983 and 1984 was 134 and 129 cm, respectively, slightly above the normal yearly accumulation. The volume‐weighted average concentrations of 7Be in bulk deposition for 1983 and 1984 were 90 and 100 dpm/L, while those for 210Pb were 5.9 and 6.6 dpm/L, respectively. The annual depositional fluxes of 7Be and 210Pb in bulk deposition in 1983 and 1984 were 12.0 and 12.9 dpm/cm2 (for 7Be) and 0.79 and 0.85 dpm/cm2 (for 210Pb), respectively. There was a high degree of correlation between 7Be and 210Pb concentrations in wet‐only deposition. This was not anticipated, considering that the sources of these two radionuclides are different. These results suggest that 7Be and 210Pb cannot be used as two independent tracers for materials originating in the stratosphere versus those from the troposphere. Dry depositional fluxes for both radionuclides, estimated from differences in the wet‐only and bulk fluxes, were calculated to be a maximum of 12 and 11% of the bulk 7Be and 210Pb fluxes, respectively. On an annual average the washout ratio for 7Be in bulk deposition was 370, while that for 210Pb was 215. The annual average total deposition velocities for 7Be and 210Pb were estimated to be 1.3 and 0.7 cm/s, respectively. It is suggested that the apparent differences in the depositional characteristics (that is, total deposition velocity, washout ratio) for these radionuclides are mere artifacts of the manner in which they are calculated and do not necessarily reflect differential behavior in the atmospheric deposition of 7Be and 210Pb.

Fine sediment sources in Conservation Effects Assessment Project watersheds

“…Temporal variations of atmospheric influxes at the Goodwin Creek site for the two radionuclides were further examined (table 2) and consistent with long-term measurements from other sites (Todd et al 1989;Wilson et al 2005). At Goodwin Creek, the atmospheric influxes of Moreover, long events or events that are preceded by multiple, other storms may experience washout of the radionuclides before the end of the event (Turekian et al 1983).…”

Influence of model resolution on the atmospheric transport of <sup>10</sup>Be

“…We simply average over whatever period the observations cover and compare them with the modelled 5-yr mean fluxes. There are 7 Be observations from 37 stations (Baskaran et al, 1993;Bleichrodt, 1978;Brown et al, 1988;Crecelius, 1981;Hasebe et al, 1981;Heikkilä et al, 2008a;Hirose et al, 2004;Huh et al, 2006;Igarashi et al, 1998;Knies, 1994;McNeary and Baskaran, 2003;Olsen et al, 1985;Todd et al, 1989;Turekian et al, 1983;Uematsu et al, 1994;Young and Silker, 1980), 210 Pb from 71 stations (Baskaran et al, 1993;Graustein and Turekian, 1986;Huh et al, 2006;Hirose et al, 2004;McNeary and Baskaran, 2003;Nijampurkar and Clausen, 1990;Todd et al, 1989;Turekian et al, 1977Turekian et al, , 1983 and 10 Be from 21 stations (Chengde et al, 1992;Graham et al, 2003;Heikkilä et al, 2008a;Monaghan et al, 1986;Somayulu et al, 1984). The modelled 5-yr mean deposition fluxes of 7 Be, 10 Be and 210 Pb are shown in Figures 4, 5 and 6, together with the location and measured flux of the observations.…”

Intra-Annual Deposition of Atmospheric 210Pb,210Po and the Residence Times of Aerosol in Xiamen, China

“…However, the fluxes of 210 Pb in Xiamen were two-to threefold higher than some mid-latitude areas, such as Odawa Bay, Izmir and Huelva (Tateda et al, 2008;Lozano et al, 2011;Uğur et al, 2011). In addition, they were close to some midNorthern regions, i.e., Galveston, Tsuyazaki, Norfolk and Stillpond (Todd et al, 1989;Baskaran et al, 1993;Kim et al, 2000a;Tateda et al, 2008) although higher values were also observed at many mid-latitudes. Similar scenario also happened to 210 Po.…”