- 1 Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, UK
- 2 The James Hutton Institute, Craigiebuckler, Aberdeen AB15 8QH, Scotland, UK
- Received 3 November 2011. Revised 7 December 2011. Accepted 7 December 2011. Available online 12 January 2012. Published online: January 12, 2012.
Lead (Pb) is a serious environmental pollutant in all its chemical forms [1]. Attempts have been made to immobilize lead in soil as the mineral pyromorphite using phosphate amendments (e.g., rock phosphate, phosphoric acid, and apatite [ [2], [3], [4] and [5]]), although our work has demonstrated that soil fungi are able to transform pyromorphite into lead oxalate [ [6] and [7]]. Lead metal, an important structural and industrial material, is subject to weathering, and soil contamination also occurs through hunting and shooting [ [8] and [9]]. Although fungi are increasingly appreciated as geologic agents [ [10], [11] and [12]], there is a distinct lack of knowledge about their involvement in lead geochemistry. We examined the influence of fungal activity on lead metal and discovered that metallic lead can be transformed into chloropyromorphite, the most stable lead mineral that exists. This is of geochemical significance, not only regarding lead fate and cycling in the environment but also in relation to the phosphate cycle and linked with microbial transformations of inorganic and organic phosphorus. This paper provides the first report of mycogenic chloropyromorphite formation from metallic lead and highlights the significance of this phenomenon as a biotic component of lead biogeochemistry, with additional consequences for microbial survival in lead-contaminated environments and bioremedial treatments for Pb-contaminated land.
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