The distribution of neodymium, lead, thorium and uranium was investigated in about 100 samples of 12 different species of common, edible and non-edible mushrooms collected in unpolluted areas in the province of Ciudad Real, Central Spain. The quantitative analysis of heavy metals was performed by X-ray fluorescence spectrometry (a simple, accurate and non-destructive method). The concentration of these elements was related to three factors: mushroom specie, life style/substrate and study area. The results reveal considerable amounts of the four metals in all species analyzed as well as significant differences on the capability to accumulate these elements. The maximum absorption of Nd and Pb was found in the ectomycorrhizal Cantharellus cibarius, reaching values of 7.10 and 4.86 microg g(-1), respectively. Thorium and uranium were mainly accumulated (3.63 and 4.13 microg g(-1), respectively) in Hypholoma fasciculare although it is an epiphyte species, isolated from the mineral particles of soil. The distribution patterns of these metals in sporocarps of different habitats and locations showed no significant differences, except for thorium, mainly accumulated in mushrooms living on wood regarding these living on soil organic matter. The species-specific is therefore the determining factor for accumulation of Nd, Pb, Th and U, more than substrate, in this study.

No abstract

A B S T R A C T : Illitic-smectitic clays were matured with a ferruginous, bicarbonate-rich and sulphate-rich water for different periods of time (7, 15, 30, 60 and 90 days), and subjected to discontinuous stirring, to test their use in pelotherapy. A progressive degradation of the clay minerals was observed during the maturation process, with a reduction in the illite and smectite crystallinity, in the percentage of smectites and in the phyllosilicate content. The percentage of <2 mm particles also decreased. These modifications caused changes in the clays' physicochemical properties, which are evident in an increase in their plasticity index and in slower cooling of the peloid, both of which improved the clays' effect in pelotherapy.

No abstract

The Carrirn lacustrine basin (,~ 10 km2), central Spain, is filled with NeogeneQuaternary sediments (20-25 m thick) rich in palygorsldte. Two clay units of ~ 15 m thick are of particular interest in the basin. The lower one contains over 75% phyllosilicates (palygorskite up to 90%, smectites and illite) in marginal areas (facies A), and it is laterally bound by a distal facies (B) also rich in clay minerals (smectites and illite, and some palygorskite) and gypsum, and includes dolomitic marl intercalations. The composition at the top is primarily marly, with some gypsum (C). The upper clay unit, mainly clay-size material, (D) is rich in smectites, palygorskite and sepiolite, and contains carbonate intercalations near the top. A statistical treatment of the mineralogical and chemical composition data from 120 samples, using principal factor analysis, suggests that: (a) illite and smectite are detrital in origin; (b) palygorskite was formed by transformation of illite and smectite involving reaction with Mg; and (c) sepiolite was a neoformation product favoured by evaporation of silica-and Mg-bearing waters.Palygorskite and particularly sepiolite are quite abundant in Spain.