Printer Friendly

Lead in cocoa and chocolate: Rankin and Flegal respond.

We thank Manton for his comments on our study (Rankin et al. 2005), and we hope that readers will be encouraged to read the entire article to place his correspondence in perspective. In our article (Rankin et al. 2005), we documented the orders of magnitude of increases in lead concentrations of processed cocoa and chocolate products over that of the lead concentration in cocoa bean nibs used in the manufacture of those products. We maintain that our conclusions are substantiated by both the data and the extensive literature documenting industrial lead contamination in the biosphere (Cocoa Producers' Alliance 2004; National Research Council 1993]. Our lead concentration measurements show that manufactured cocoa and chocolate products exhibit contamination not found in the source material--cocoa bean nibs. As detailed in the article, the average lead concentration of the cocoa bean nibs was among the lowest reported values for a natural food, whereas the lead concentrations of the cocoa products were up to over 300-fold higher; as we noted in our article (Rankin et al. 2005), those relatively high levels of lead have been acknowledged by the Cocoa Producers' Alliance (Lagos, Nigeria).

Because the concentration measurements indicated that this contamination was not naturally derived, we analyzed other materials for lead concentrations and lead isotopic composition to determine possible sources of the increase in lead in cocoa products. We are unsure about the origination of additional points in Figures 2 and 4, but we used the data listed in Table 3 in forming our original conclusions, and we continue to support those conclusions. To suggest, as Manton does, that the lead isotopic composition measurements show that the contamination is naturally derived is disingenuous and inconsistent with the extensive literature using lead isotopic compositions to characterize potential sources--natural and industrial--of lead in the biosphere (Cocoa Producers' Alliance 2004; National Research Council 1993). We maintain that the lead isotopic composition measurements suggest that, although it may be possible for some contamination originating at the cocoa farms to be transferred to the final products, the majority of contamination must accumulate during shipping and/or manufacturing, as both the lead concentrations and lead isotopic compositions of cocoa and chocolate products indicate.

Finally, we are disappointed with Manton's comment regarding our declaration of no competing financial interests. In our article (Rankin et al. 2005), we listed the American Environmental Safety Institute (AESI) as a source of funding. The institute provided some of the funding for the chemical analyses, scientific interpretation, and litigation depositions, but these were all done with the agreement that our study would be equipoised--conducted without bias. Moreover, the litigation was settled well before our manuscript was written, and we neither received nor requested funding from the AESI or any other organization or any individual involved in the litigation for the preparation or publication of the article.

The authors declare they have no competing financial interests.


Cocoa Producers' Alliance. 2004. Proposed Methodology to Determine Source and Level of Lead Contamination in Cocoa. Available: [accessed 26 January 2006].

National Research Council. 1993. Measuring Lead Exposure in Infants, Children end Other Sensitive Populations. Washington, DC:National Academy Press.

Rankin CW, Nriagu JO, Aggarwal JK, Arowolo TA, Adebayo K, Flegal AR. 2005. Lead contamination in cocoa and cocoa products: isotopic evidence of global contamination. Environ Health Perspect 113:1344-1348.

Charley W. Rankin

A. Russell Flegal

Environmental Toxicology, WIGS,

University of California, Santa Cruz

Santa Cruz, California

COPYRIGHT 2006 National Institute of Environmental Health Sciences
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2006, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:Perspectives: Correspondence
Author:Flegal, A. Russell
Publication:Environmental Health Perspectives
Date:May 1, 2006
Previous Article:Sources of lead in cocoa and chocolate.
Next Article:Taking the lead and copper rule to task.

Related Articles
Enlightened Indulgence.
Chocolate! Purely a guilty pleasure? Pure fiction!
Lead in cocoa products: where does contamination come from?
Chocolate's dark side.
Storage conditions compromise texture, quality of chocolate.
Chocolate: who makes it, who eats it.
Sources of lead in cocoa and chocolate.
Your dark master ... the cocoa bean!
Not just heavenly, it's divine: balancing the scales with justly traded chocolate.

Terms of use | Privacy policy | Copyright © 2018 Farlex, Inc. | Feedback | For webmasters