Studies of the Influence of Graded Storm Layers on 210Pb and Heavy Metals Profiles in Great Barrier Reef Sediments
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- 作者：Philip H. Towler and J. David Smith
- 刊名：Environmental Science & Technology
- 出版年：2000
- 出版时间：July 15, 2000
- 年：2000
- 卷：34
- 期：14
- 页码：2947 - 2951
- 全文大小：105K
- 年卷期：v.34,no.14(July 15, 2000)
- ISSN：1520-5851
文摘
Intense storm activity can resuspend surficial sedimentsin coastal regions resulting in the formation of graded layersin the sediment. This occurs in the Great Barrier Reefarea of northeastern Australia where tropical cyclones arecommon. The vertical redistribution of 210Pb and heavymetals in these graded sediment layers has been examinedmathematically using a model based on Stokes's Law ofsettling and experimentally using laboratory simulations. Thevertical profiles of 210Pb and heavy metal concentrationsshow an increase with the increasing proportion offine particles toward the sediment-water interface. Thecalculated and experimental results mimic 210Pb-depth profilesproduced where there has been a constant rate ofsedimentation. The use of 210Pb as a geochromometer insediments including unidentified graded storm layers mayyield incorrect sedimentation rates and false geochronologies. The redistribution of heavy metals is similar andmay incorrectly suggest recent increases in heavymetal inputs. This misinterpretation is significant wherethe results are used in making environmental managementdecisions.