Title

Evidence for biomagnification of rubidium in freshwater and marine food webs

Document Type

Article

Publication Date

5-1-2005

Publication Title

Canadian Journal of Fisheries and Aquatic Sciences

Volume

62

Issue

5

First Page

1161

Last Page

1167

Abstract

Rubidium (Rb), a rarely studied alkali metal, may be an essential ultra-trace element for humans and other organisms. However, very little information exists in regard to the concentrations and distribution of Rb in freshwater and marine food webs. We measured Rb concentrations in freshwater fish from Lake Erie and two Arctic lakes (Lake Hazen and Resolute Lake) and in seabirds, ringed seals, and invertebrates from the marine Northwater Polynya in Baffin Bay. The alkali analogues of Rb, cesium (Cs), and potassium (K) were also analysed in a subset of fish from Lakes Erie and Hazen. Rb and Cs concentrations and Cs:K ratios in the sampled biota are significantly regressed against δ15N values, indicating biomagnification through the food web in diverse ecosystems. However, there is no relationship between K concentrations and δ15N values, indicating a lack of biomagnification and the presence of homeostatistic mechanisms for this essential trace element. Rb must be included with mercury and Cs as metals that consistently biomagnify in diverse food webs and should be considered in multi-element biomagnification studies. © 2005 NRC.

DOI

10.1139/f05-027

ISSN

0706652X

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