 |
| Titel |
Improvement of chemical and biological characteristics of gossan mine wastes following application of amendments and growth of Cistus ladanifer L. |
| VerfasserIn |
Erika Santos, Maria Manuela Abreu, Felipe Macías, Amarilis de Varennes |
| Konferenz |
EGU General Assembly 2013
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250079217
|
|
|
|
|
|
| Zusammenfassung |
| Cistus ladanifer is considered a good option for phytostabilization of mine wastes, composed
of several materials, but its growth is very slow due to substrata conditions (acidic pH, low
fertility and water availability, high total concentrations of hazardous elements). To enhance
the growth of C. ladanifer with application of organic/inorganic amendments can be a
strategy to speed up remediation. This study aimed to evaluate the influence of different
rates of amendments and C. ladanifer growth on the improvement of chemical and
biological characteristics of gossan wastes. Composite samples of mining wastes
(gossan+host rocks) were collected at the São Domingos mine. Amendments used were
mixtures (30, 75, 150 Mg/ha) of rockwool, agriculture wastes and wastes from liquor
distillation obtained from fruits of Arbutus unedo. Four treatments (n=6 replicates) were
carried out (control and three amended treatments) under controlled conditions in a
greenhouse. After one month of incubation at 70% of water holding capacity, C.
ladanifer was sown in half of the pots from each treatment (n=3), and the other
three pots remained in the same conditions without plant. Chemical and biological
characteristics of the wastes (with/without plants) were analysed after incubation and fifteen
months.
Gossan wastes had great total concentrations of several elements (g/kg; Al: 24.8, As:
3.03, Cu: 0.23, Pb; 9.21) whereas in an extracting solution (diluted solution of organic acids)
these were small (0.5 units),
fertility (Corganic, Pextractable, Ntotal) and dehydrogenase activity of mine wastes,
principally with the rate of 150 Mg/ha, even after one month of incubation and after
the plants be sown. In both sampling periods (beginning/end of the experiment),
Kextractable concentrations increased only with the high application rates (control
and 30 Mg/ha treatment: 1.02–1.88 mg/kg; other amended treatments: 2.13–3.55
mg/kg).
At the end of the experiment, the presence of the plant increased Corganic and Pextractable
concentrations, compared to treatments without plants, reaching the highest values in the
treatments combining amendments and plants. After one month of incubation, the
dehydrogenase activities in wastes were more than twice in the amended treatments
(1.71–33.55 μg TPF g sample 16h-1, depending on amendments application rate and
sampling period). Nevertheless, wastes from treatments with plants had higher
dehydrogenase activities (9.66–33.55 μg TPF g sample 16h-1, depending on amendments
application rate) than in treatments using only amendments (4.98–22.30 μg TPF g sample
16h-1), but both were higher than control. The plants in control presented lower fresh
biomass than in amended treatments. Plants growth in control was not sufficient to enhance
dehydrogenase activity of mine wastes (1.51 and 1.72 μg TPF g sample 16h-1, with/without
plants, respectively).
The extractable nutrients (Ca, Fe, K, Mg, Mn, Zn) increased with amendment application,
an advantage for remediation purposes. Although extractable Al, As, Na also increased
in the same treatments, they remained small. In contrast, extractable Cu and Pb
were, generally, lower in amended treatments than in control. The presence of the
plant did not increase the concentration of elemental in the extractant solution. |
|
|
|
|
|
|