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Titolo:
New isotopic evidence for chronic lead contamination in the San Francisco Bay estuary system: Implications for the persistence of past industrial lead emissions in the biosphere
Autore:
Steding, DJ; Dunlap, CE; Flegal, AR;
Indirizzi:
Univ Calif Santa Cruz, Dept Earth Sci, WIGS, Santa Cruz, CA 95064 USA UnivCalif Santa Cruz Santa Cruz CA USA 95064 S, Santa Cruz, CA 95064 USA
Titolo Testata:
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
fascicolo: 21, volume: 97, anno: 2000,
pagine: 11181 - 11186
SICI:
0027-8424(20001010)97:21<11181:NIEFCL>2.0.ZU;2-O
Fonte:
ISI
Lingua:
ENG
Soggetto:
WESTERN NORTH-ATLANTIC; ANTHROPOGENIC LEAD; ATMOSPHERIC LEAD; HEAVY-METALS; TRANSPORT; OCEAN; DEPOSITION; CALIFORNIA; SNOW; AIR;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
44
Recensione:
Indirizzi per estratti:
Indirizzo: Steding, DJ Univ Calif Santa Cruz, Dept Earth Sci, WIGS, 1156 High St, Santa Cruz, CA 95064 USA Univ Calif Santa Cruz 1156 High St Santa Cruz CA USA 95064 USA
Citazione:
D.J. Steding et al., "New isotopic evidence for chronic lead contamination in the San Francisco Bay estuary system: Implications for the persistence of past industrial lead emissions in the biosphere", P NAS US, 97(21), 2000, pp. 11181-11186

Abstract

Measurements of lead isotope compositions in unfiltered San Francisco Bay waters from 1989 to 1998 have brought new insights into the cycling of anthropogenic lead in estuaries. Isotopic compositions of lead in the shallow (<2 m) southern reach were essentially invariant (similar to 90% derived from 1960s-1970s leaded gasoline) during the study period because of limited hydraulic flushing and the remobilization of lead from bottom sediments. In contrast, in the northern reach freshwater flushing from the San Joaquin and Sacramento rivers produced seasonal and decadal variations in lead isotope compositions. The seasonal shifts are attributed to advection of soils containing late 1980s gasoline lead into the bay during winter rains. Mass balance calculations indicate that only a small fraction (1-10%) of this leaded gasoline fallout from the late 1980s has been washed out of the San Joaquin and Sacramento rivers' drainage basin by 1995. Superimposed on this seasonal cycling was a long-term systematic shift in the component of gasolinelead expressed in the river systems, with a small (similar to 5-10%) decrease in the amount of 1960s-1970s gasoline lead in river and North Bay waters. The retention of gasoline lead in the river systems draining into the bay as well as San Francisco Bay sediments indicates that historic gasoline deposits may remain in the combined riparian/estuarine system for decades. Such a persistence is in contraindication to recent reports of rapid (annual) decreases in lead contamination in other environments, and the link between climate and contaminant transport suggests local or global climate change will have an impact on contaminant distribution and fate.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 18/09/20 alle ore 19:33:13