Publication Date:
2017-04-04
Description:
Active volcanoes emit considerable amounts of
contaminants such as As, Se and V. Mount Etna is the biggest
volcano of Europe and an excellent geochemical site to study
water-soil processes. Due to its volcanic activity, the rainwater
has a strong compositional gradient, both in time and space.
At present, the behaviour of trace elements in the soils around
Mt Etna is poorly understood. To determine the influence of
the rainwater pH on the potential mobilization of geogenic
pollutants, batch experiments have been performed with
synthetic rainwater for 25 soils collected along the flanks of
the volcano. Our results show that:
i) The maximum concentrations in the leaching solutions are
higher for acid rain than for neutral rain (e.g. 7.7 vs 1.3
mg/L for Se).
ii) With neutral rain conditions the soils upwind from the
volcano have higher concentrations of Se than those
downwind (up to 1.3 mg/L compared to ≤0.3 mg/L for
the other samples). This trend is less clear for As and V.
iii) For soils collected from 2 to 10 km downwind of the
craters, Se concentrations in acid rain leachates decrease
one order of magnitude with increasing distance. A
similar pattern is also observed upwind from the
volcano. For As and V no clear relationship between
concentrations and location with respect to the volcanic
craters is observed.
Both i) and ii) result in a low pH dependence for samples
upwind from the volcano. The biggest difference between acid
and neutral leaching for As and V is observed for a sample 2
km downwind from the craters. The observed patterns are
influenced by potential controlling factors, such as organic
matter content, total concentrations, mineralogy, influence of
the volcanic plume, etc. Our results have implications for the
chemical composition of the Etnean aquifer, the only water
resource to the one million inhabitants around Mt Etna, as well
as for the bioavailability and potential toxicity through
agricultural activities, essential to the local economy.
Description:
Published
Description:
Davos, Switzerland
Description:
4.4. Scenari e mitigazione del rischio ambientale
Description:
open
Keywords:
volcanic soils
;
selenium
;
arsenic
;
vanadium
;
01. Atmosphere::01.01. Atmosphere::01.01.07. Volcanic effects
;
03. Hydrosphere::03.03. Physical::03.03.01. Air/water/earth interactions
;
05. General::05.02. Data dissemination::05.02.01. Geochemical data
;
05. General::05.08. Risk::05.08.01. Environmental risk
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
Oral presentation
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