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Titolo:
Use of Rn-222 and Ra-226 to trace groundwater discharge into the Chesapeake Bay
Autore:
Hussain, N; Church, TM; Kim, G;
Indirizzi:
Univ Delaware, Coll Marine Studies, Newark, DE 19716 USA Univ Delaware Newark DE USA 19716 ll Marine Studies, Newark, DE 19716 USA
Titolo Testata:
MARINE CHEMISTRY
fascicolo: 1-2, volume: 65, anno: 1999,
pagine: 127 - 134
SICI:
0304-4203(199905)65:1-2<127:UORART>2.0.ZU;2-8
Fonte:
ISI
Lingua:
ENG
Soggetto:
BLOOMS;
Keywords:
groundwater; water column; algal blooms;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Physical, Chemical & Earth Sciences
Citazioni:
20
Recensione:
Indirizzi per estratti:
Indirizzo: Hussain, N Univ Delaware, Coll Marine Studies, Newark, DE 19716 USA Univ Delaware Newark DE USA 19716 tudies, Newark, DE 19716 USA
Citazione:
N. Hussain et al., "Use of Rn-222 and Ra-226 to trace groundwater discharge into the Chesapeake Bay", MAR CHEM, 65(1-2), 1999, pp. 127-134

Abstract

Activities of Rn-222 and Ra-226 were measured in water samples from the Chesapeake Bay during two summers and one winter in 1995 and 1997 in order todevelop a potential groundwater tracer. A major estuary to the Bay, the Potomac, was Rn-222 activities ranged between also sampled for these nuclidesduring 1997 in order to assess their inputs to the Bay. The about 20 and 140 dpm/100 l within the Chesapeake Bay. Higher activities were encountered at the northern end of the Bay. In the upper Potomac. activities as high as200-300 dpm/100 l were observed. These activities are twice to as much as two orders of magnitude higher than coastal ocean Rn. The activities generally decrease with salinity and depth to the south and show little change between summer and winter. The 222Rn activities are much in excess of its parent Ra-226 which suggests an active disequilibrated source of Rn-222 to these waters. Considering the short half-life of Rn-222 (3.8 days) and its limited exchange with the atmosphere, another important source is suggested tobe the exchange of groundwater in lower salinity regions of the Bay or itstributaries. The inverse trend of Rn against salinity is consistent with afresh groundwater end member from the Chesapeake Bay watershed. The Rn-222concentrations of the Potomac tributary are even greater than in the Bay, increasing from 47 dpm/100 l at the Bay entrance to about 280 dpm/100 l upstream and suggest an even more significant groundwater discharge. Calculations suggest as much as 10% of freshwater inputs to the Chesapeake Bay couldbe from groundwater. (C) 1999 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 30/11/20 alle ore 19:33:48