Publication
Using indicator kriging for the evaluation of arsenic potential contamination in an abandoned mining area (Portugal)
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Advisor(s)
Abstract(s)
Mining and mineral-processing activities canmodify the environment in a variety of ways. Sulfide mineralization
is notorious for producing waters with high metal contents. Arsenic is commonly associated with sulfide mineralization
and is considered to be toxic in the environment at low levels. The studied abandoned mining area is
located in central Portugal and the resulting tailings and rejected materials were deposited and exposed to the
air and water for the last 50 years. Sixteen water sample-points were collected. One of these was collected
outside the mining influence, with the aim of obtaining a reference background.
The risk assessment, concerning the proximity to abandoned mineralized deposits, needs the evaluation of
intrinsic and specific vulnerabilities aiming the quantification of the anthropogenic activities. In this study,
two indicator variables were constructed. The first one (I1), a specific vulnerability, considers the arsenic
water supply standard value (0.05 mg/L), and the probability of it being exceeded is dependent on the
geologic and hydrological characteristics of the studied area and also on the anthropogenic activities. The
second one (I2), an intrinsic vulnerability, considers arsenic background limit as cut-off value, and depends
only on the geologic and hydro-geological characteristics of the studied area.
At Segura, the arsenic water content found during December 2006 (1.190 mg/L) was higher than the arsenic
water content detected in October 2006 (0.636 mg/L) which could be associated to the arsenic released from
Fe oxy-hydroxide. At Segura abandoned mining area, the iso-probability maps of October 2006 and December
2006, show strong anomalies associated with the water drainage from abandoned mining activities. Near the
village, the probability of exceeding the arsenic background value is high but lower than the probability of
exceeding the arsenic water supply value. The arsenic anomalies indicate a high probability for water arsenic
contamination and those waters should not be used for human consumption.
Description
Keywords
Sulfide mines Arsenic Waters Contamination Indicator kriging Segura
Citation
ANTUNES, I.M.H.R. ; ALBUQUERQUE, M.T.D. (2013) - Using indicator kriging for the evaluation of arsenic potential contamination in an abandoned mining area (Portugal). Science of the Total Environment. ISSN 0048-9697. 442, p. 545-552.