Macrofungi on uranium mill tailings — Associations and metal content

Abstract

Sporocarps of three species of Ascomycota and ten species of Basidiomycota were collected from abandoned uranium mill tailings. On these sites some natural colonisation by vegetation had occurred in the last 20 years. The existing vegetation provides some circumstantial evidence for mycorrhizal associations with Pinus strobus, Populus balsamifera, P. tremuliodes, and Salix sp. A new record for Helvella corium in Ontario requires confirmation. For twelve fungal collections, representing three different tailings sites, analysis of elemental composition by neutron activation was carried out, Al, Ba, Ca, Mg, Mn and Na. Fungal concentrations of these elements were for the most part much higher than previously published values; however, the respective substrate values were also higher than values for most soils. Concentration factors rarely exceeded unity. When collections were compared, concentration factors (c.f.) for Mn were consistently higher than c.f.'s for Ba, Al or Mg, with the single exception of Ba in the ascomycete Sepultaria on Madawaska site which had a concentration factor of 1.3. The possible significance of the findings for revegetation of uranium tailings, and for fungal tolerance of high mineral substrates is considered.