Luo and Ku have reanalyzed part of the data set we published in 2002 to address the question of the differential scavenging of thorium, protactinium and beryllium by different particulate phases (organic carbon, lithogenic material, opal and calcium carbonate). They conclude upon reanalysis that the data are consistent with their earlier proposal, based on sediment separation experiments, that lithogenic material possesses an affinity for Th some 500 times greater than do biogenic phases. While we welcome new analyses and fresh interpretations of our data set we have to disagree with their conclusion that the partition coefficient (K_d) for adsorption of Th onto lithogenic particles (K_d(Th)_L) is on the order of 2.3×10⁸, and far greater than the K_d for adsorption of Th onto calcium carbonate (K_d(Th)_C). Here we show that such a high value for K_d(Th)_L is inconsistent with a large body of observations. These observations suggest K_d(Th)_L is closer to 1×10⁷, consistent with our previous study.

Item Type:	Refereed Article
Keywords:	thorium, protactinium, scavenging, particle composition, partition coefficient
Research Division:	Earth Sciences
Research Group:	Oceanography
Research Field:	Chemical Oceanography
Objective Division:	Expanding Knowledge
Objective Group:	Expanding Knowledge
Objective Field:	Expanding Knowledge in the Earth Sciences
Author:	Chase, Z (Associate Professor Zanna Chase)
ID Code:	101433
Year Published:	2004
Web of Science® Times Cited:	25
Deposited By:	IMAS Research and Education Centre
Deposited On:	2015-06-24
Last Modified:	2015-09-23
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