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Subject Domain (in DDC) Computer science, information & general works ♦ Data processing & computer science
Subject Keyword Dry Soil ♦ Pyrite Mine ♦ Remediation Measure ♦ Soil Affected ♦ Mg Zn ♦ Zn Concentration ♦ Unaffected Soil ♦ Remediation Action ♦ Aznalc Llar Mine ♦ Autumn Winter ♦ Geochemical Background ♦ Affected Soil ♦ Enormous Effort
Abstract georeferenced soils uniformly distributed throughout the area affected by the spill from the Aznalcóllar mine (April 1998) were analysed at three depths (0– 10, 10–30, and 30–50 cm) and on four dates (autumn–winter 1998, 1999, 2001, and 2004). For an estimate of the geochemical background, 30 unaffected soils near the edge of the spill were also analysed at the same depths. The soils were contam-inated before the spill and, the accident seriously increased the concentration of As and Zn in the first 10 cm of almost all the affected soils. After the enormous efforts of cleaning up the tailings, around 45 % of the soils had a concentration higher than 100 mg As kg−1 dry soil, and some 35 % had a concentration higher than 1,000 mg Zn kg−1 dry soil. Both As and Zn penetrated between 10 and 30 cm in 25 % and 45 % of the soils, respectively, but reached 30 cm in only 12 % of the soils. The remediation actions, especially the tilling and homogenisation of the uppermost 25 cm of the all soils, caused the As and Zn concentrations to decline in the soils, but this change was not very effective from the standpoint of pollution. Thus, 6 years after the spill, the uppermost 10 cm of 30 % of the soils continued to have an As concentration higher than 100 mg As kg−1, while the Zn concentration diminished considerably on the surface due to its greater mobility, accumulating between 10 and 30 cm in depth, where 20 % of the soils continued to register more than 1,000 mg Zn kg−1 dry soil.
Educational Role Student ♦ Teacher
Age Range above 22 year
Educational Use Research
Education Level UG and PG ♦ Career/Technical Study
Publisher Date 2008-01-01