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Titolo:
Factors influencing the atmospheric depositional fluxes of stable Pb, Pb-210, and Be-7 into Chesapeake Bay
Autore:
Kim, G; Hussain, N; Scudlark, JR; Church, TM;
Indirizzi:
Univ Delaware, Grad Coll Marine Studies, Newark, DE 19716 USA Univ Delaware Newark DE USA 19716 ll Marine Studies, Newark, DE 19716 USA
Titolo Testata:
JOURNAL OF ATMOSPHERIC CHEMISTRY
fascicolo: 1, volume: 36, anno: 2000,
pagine: 65 - 79
SICI:
0167-7764(200005)36:1<65:FITADF>2.0.ZU;2-6
Fonte:
ISI
Lingua:
ENG
Soggetto:
DRY DEPOSITION; TRACE-ELEMENTS; NORTH-ATLANTIC; PRECIPITATION; VARIABILITY; BERYLLIUM-7; YEAR-1; AIR;
Keywords:
lead; pollution; mid-Atlantic bight; radionuclide; air mass;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Physical, Chemical & Earth Sciences
Citazioni:
27
Recensione:
Indirizzi per estratti:
Indirizzo: Kim, G Florida State Univ, Dept Oceanog, Tallahassee, FL 32306 USA FloridaState Univ Tallahassee FL USA 32306 lahassee, FL 32306 USA
Citazione:
G. Kim et al., "Factors influencing the atmospheric depositional fluxes of stable Pb, Pb-210, and Be-7 into Chesapeake Bay", J ATMOS CH, 36(1), 2000, pp. 65-79

Abstract

Atmospheric depositional fluxes of Be-7 and Pb-210 (bulk) and stable Pb (wet) were measured simultaneously for one year (from September 1995-August 1996) at Stillpond, Maryland on the upper eastern shore of the Chesapeake Bay. The annual total (bulk) depositional fluxes of Pb-210 and Be-7 were 0.78and 13 dpm cm(,)(-2) respectively, and agree well with other previously reported results at nearby locations such as Norfolk, VA and Lewes, DE. The wet depositional flux of stable Pb (58 ng cm(-2) yr(-1)) was also similar tothat measured at other Chesapeake sites during 1990-1991 (55 ng cm(-2) yr(-1), for both Wye and Elms, Maryland). This suggests that a constant Pb flux has been reached since the mandatory use of unleaded gasoline was instituted. The concentrations of Be-7, Pb-210, and to a lesser extent stable Pb were diluted exponentially by precipitation, based on concentrations versus precipitation plots. Due to higher enrichment of Pb-210 in the lower troposphere, the dilution effect was largest on Pb-210 (i.e., controlled mainly by below-cloud scavenging processes), and thus its depositional flux increase is negligible as precipitation amount increases. A good correlation between the amount of precipitation and total depositional flux of Be-7 and stable Pb, which are more enriched in the upper troposphere, suggests that precipitation amount is important in controlling their fluxes (i.e., controlledby both below-cloud scavenging and in-cloud condensation processes). Basedon Be-7 versus Pb-210 plots, it appears that Be-7, relative to Pb-210, is less efficiently scavenged by snowfall. Our results suggest that in addition to precipitation amounts, marine air-mass transport or snowfall may be important factors in controlling the seasonal variability of the fallout fluxes of trace metals in coastal areas.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 30/11/20 alle ore 20:09:24