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Heavy Metal Anomalies in Coastal Sediments of O'ahu, Hawai'i
|Title:||Heavy Metal Anomalies in Coastal Sediments of O'ahu, Hawai'i|
|Authors:||McMurtry, Gary M.|
Wiltshire, John C.
Kauahikaua, James P.
|Issue Date:||Oct 1995|
|Publisher:||University of Hawaii Press|
|Citation:||McMurtry GM, Wiltshire JC, Kauahikaua JP. 1995. Heavy metal anomalies in coastal sediments of O'ahu, Hawai'i. Pac Sci 49(4): 452-470.|
|Abstract:||Interelement ratios to Cr in surface samples of coastal sediments
and watershed soils of Oah'u, Hawai'i, show widespread, anomalous concentrations
of Pb, Cd, and Hg when compared with basalt, the ubiquitous rock
type. Enrichments of these heavy metals are especially pronounced in the carbonate
sands of Kahana, Maunalua, and Mamala Bays, where enrichment
factors for Pb, Cd, and Hg range from 84 to 240, 67 to 180, and 43 to 72,
respectively, based on samples collected in the early 1970s. Lesser enrichments
of Cu, Zn, and Ni generally parallel those of Pb, Cd, and Hg in highly contaminated
areas at Pearl and Honolulu Harbors, and in cultivated watershed soils.
Estimated deposition rates for Pb, Cd, and Hg from three major local source
categories-motor vehicle, agriculture, and volcanic-indicate that motor vehicles
are by far the largest source of Pb enrichments in O'ahu soils and sediments.
Widespread mercury deposition is apparently dominated by local volcanic
sources, whereas Cd deposition is more evenly dispersed among the three
major sources. The estimated Pb and Cd deposition rates are in reasonable
agreement with their observed sediment and soil burdens in the early 1970s. The
estimated Hg deposition rates are higher than necessary to explain the observed
burdens for this metal, possibly as a result of soil leaching, postdepositional
volatility, or Hg uptake and re-emission by biota.
|Appears in Collections:||Pacific Science Volume 49, Number 4, 1995|
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