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| Titel |
Background and baseline values for thallium and antimony in soils from Murcia Region (SE, Spain) and their relationship with mineralogical composition |
| VerfasserIn |
M. J. Martínez-Sánchez, C. Pérez-Sirvent, M. L. García-Lorenzo, M. L. Tudela, J. Molina, J. Bech |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250022293
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| Zusammenfassung |
| Thallium minerals are very rare and are formed exclusively during the epithermal stage of
hydrothermal activity or under supergene conditions. Examples of these minerals include
lorandite (TlAsS2), picotpaulite (TlFe2S3) and vrbaite (Hg3Tl4As8Sb2S20). Thallium is
extremely toxic, but little studied, affecting the central nervous system.
Antimony is a low-abundance chalcophile element forming several rather rare minerals
including stibnite (Sb2S3), valentinite (Sb2O3) and kermesite (Sb2S2O), but is more usually
present at trace levels in minerals such as ilmenite, Mg-olivine, galena, sphalerite and pyrite.
Antimony has no known function in living organisms and high concentrations of Sb are
highly toxic.
The objective of this study was to determine the thallium and selenium background and
baseline levels in soils from the Region of Murcia (Southeast, Spain) and to study the
possible relationship between mineralogical composition, soil properties and antimony and
thallium concentration.
Sampling sites corresponded to areas subjected to high and similar agricultural activity or
soils with natural vegetation, which correspond to abandoned agricultural areas. A total of
490 samples were collected, and the mineralogical composition and thallium and antimony
content were determined. Samples were analysed for antimony content by atomic
fluorescence spectrometry (AFS) and by inductively coupled plasma spectrometry (ICP-MS)
for thallium content.
The results showed that the concentration of target metals was correlated with the
mineralogical composition. Thus, thallium and antimony level was positively correlated with
the phylosilicate content and with amphibole, quartz and calcite content. In addition, both
metals were positively correlated. In summary, the background level for thallium and
antimony, showed as the median, was 0.20 mg kg-1 and 1.06 mg kg-1 respectively. Baseline
level, showed as mean+ 2*Std. deviation, was 0.64 mg kg-1 for thallium and 3.12 mg
kg-1 for antimony. Given that heavy metal concentrations in the study area were
similar to those analysed in other areas of similar lithological characteristics, it
follows that the background and baselines values established could be comparable to
background and baselines values in other areas with a similar geological substrate. |
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