Atmospheric fluxes of ²¹⁰Pb to the western Mediterranean Sea and the Saharan dust influence

Abstract

[1] Pb 210 is a well known tracer of particle dynamics in the marine environment. Geochemical models partially rely on the knowledge of its atmospheric input. Unfortunately, this is poorly known in the western Mediterranean Sea, especially regarding long-term records. In this work we have evaluated the , and were strongly correlated (R 2 = 0.95) with mean annual rainfall. This provides the possibility to determine 210 Pb fluxes in a given location if the mean annual rainfall is well known, a useful outcome for both marine biogeochemical and soil erosion studies in this region. We have also estimated the mean annual atmospheric flux of 210 Pb due to Saharan dust events registered in total deposition north of Barcelona during the last 17 years, yielding a value of 20 Bq m À2 yr À1 . This flux represents a fraction of about 16% of the total atmospheric deposition of 210 Pb in this area, but it could be up to 50% in sites with lower rainfall.

Water Circulation, Sediment Transport, and Pollutant Dynamics in Southern Iberia Waters: A Review on Numerical Modelling Studies

“…[84]. A more detailed evaluation may be seen in [85]; however the use of a mean value (which also is in good agreement with the average calculated by these last authors) is enough for our modelling purposes. In normal river water, 210 Pb concentrations are low, about 0.2 Bq/m 3 [86], and most of it is present in suspended particles.…”

Human health risk assessment of environmental and dietary exposure to natural radionuclides in the Catalan stretch of the Ebro River, Spain

“…The measured concentrations of 210 Pb in soils collected near the Ebro River are similar to those recently reported in the western Mediterranean Sea (Garcia-Orellana et al 2006). Geological characteristics of soils are a fundamental parameter to understand the radiological burdens of specific locations.…”

Aerosol deposition and origin in French mountains estimated with soil inventories of 210Pb and artificial radionuclides

“…Assuming that there was no local source of R NWT in the continental boundary layer (Monaghan, 1989) and that any increase in 210 Pb/ R NWT is due to the deposition of 210 (Appleby, 2001). Also plotted samples from the Mediterranean Area (Garcia-Orellana et al, 2006;Preiss et al, 1996;Sanchez-Cabeza et al, 2007) and Scandinavia (Peter Appleby, personal communication Table 3 esi) and effects of occult deposition are surely different depending on the direction of the slope. In Montagne Noire, samples were collected in different sub-valleys along the southern slope side influenced by Mediterranean incoming wind (called ''Autan'').…”

“…We suggest rather that Mediterranean rains, short but intense, have a more efficient washout ratio than in oceanic rains (Masson and Le Roux, submitted). Additionally, higher 210 Pb flux can also be explained by the influence of Sahara dust (Garcia-Orellana et al, 2006). (Fig.…”