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Titolo:
Stable lead isotopic analyses of historic and contemporary lead contamination of San Francisco Bay estuary
Autore:
Ritson, PI; Bouse, RM; Flegal, AR; Luoma, SN;
Indirizzi:
Portland Community Coll, Portland, OR 97219 USA Portland Community Coll Portland OR USA 97219 oll, Portland, OR 97219 USA US Geol Survey, Menlo Park, CA 94025 USA US Geol Survey Menlo Park CA USA94025 l Survey, Menlo Park, CA 94025 USA Univ Calif Santa Cruz, Earth Sci Board, Santa Cruz, CA 95064 USA Univ Calif Santa Cruz Santa Cruz CA USA 95064 d, Santa Cruz, CA 95064 USA
Titolo Testata:
MARINE CHEMISTRY
fascicolo: 1-2, volume: 64, anno: 1999,
pagine: 71 - 83
SICI:
0304-4203(199902)64:1-2<71:SLIAOH>2.0.ZU;2-L
Fonte:
ISI
Lingua:
ENG
Soggetto:
ANTHROPOGENIC LEAD; EXPOSURE; CALIFORNIA; CHILDREN; CADMIUM;
Keywords:
lead; San Francisco Bay estuary; contamination;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Physical, Chemical & Earth Sciences
Citazioni:
37
Recensione:
Indirizzi per estratti:
Indirizzo: Ritson, PI Portland Community Coll, POB 19000, Portland, OR 97219 USA Portland Community Coll POB 19000 Portland OR USA 97219 219 USA
Citazione:
P.I. Ritson et al., "Stable lead isotopic analyses of historic and contemporary lead contamination of San Francisco Bay estuary", MAR CHEM, 64(1-2), 1999, pp. 71-83

Abstract

Variations in stable lead isotopic composition (Pb-204, Pb-206, Pb-207, Pb-208) in three sediment cores from the San Francisco Bay estuary document temporal changes in sources of lead during the past two centuries. Sediment,with lead from natural geologic sources, and relatively homogeneous lead isotopic compositions are overlain by sediments whose isotopic compositions indicate change in the sources of lead associated with anthropogenic modification of the estuary. The first perturbations of lead isotopic compositionin the cores occur in the late 1800s concordant with the beginning of industrialization around the estuary. Large isotopic shifts, toward lower Pb-206/Pb-207, occur after the turn of the century in both Richardson and San Pablo Bays. A similar relationship among lead isotopic compositions and lead concentrations in both Bays suggest contamination from the same source (a lead smelter). The uppermost sediments (post 1980) of all cores also have a relatively homogenous lead isotopic composition distinct from pre-anthropogenic and recent aerosol signatures. Lead isotopic compositions of leachatesfrom fourteen surface sediments and five marsh samples from the estuary were also analyzed, These analyses suggest that the lead isotopic signature identified in the upper horizons of the cores is spatially homogeneous amongrecently deposited sediments throughout the estuary. Current aerosol lead isotopic compositions [Smith, D.R., Niemeyer, S., Flegal, A.R., 1992. Lead sources to California sea otters: industrial inputs circumvent natural leadbiodepletion mechanisms. Environmental Research 57, 163-175] are distinct from the isotopic compositions of the surface sediments, suggesting that the major source of lead is cycling of historically contaminated sediments back through the water column. Both the upper core sediments and surface sediments apparently derive their lead predominantly from sources internal to the estuary. These results support the idea that geochemical cycling of leadbetween sediments and water accounts for persistently elevated lead concentrations in the water column despite 10-fold reduction of external source inputs to San Francisco Bay [Flegal, A.R., Rivera-Duarte, I., Ritson, P.I., Scelfo, G., Smith, G.J., Gordon, M., Sanudo-Wilhelmy, S.A., 1996, Metal contamination in San Francisco Waters: historic perturbations, contemporary concentrations, and future considerations in San Francisco Bay. In: Hollobaugh, J.T. (Ed.), The Ecosystem. AAAS, pp. 173-188]. (C) 1999 Elsevier ScienceB.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 26/09/20 alle ore 03:34:49