Optimized treatment for the phytostabilization of an acid contaminated soil in La Union-Cartagena (Spain)

Juan Carlos Galán Robles

Master's thesis

Abstract:

Contamination due to trace pollutants compounds has become a serious problem in Cartagena, Spain, where mining activities have been carried out during centuries. The dispersion of these contaminants such as Iron, Lead, Cadmium, Nickel, Arsenic, Magnesium and Manganese, caused mainly by surface run-off, has an important environmental impact on the ecosystem and the high level of toxicity might be affecting nearby regions. Few studies proposing a suitable and realistic soil treatment have been done. In this context, to deal with this situation, phytoremediation with Dittrichia viscosa has been proposed. Due to the toxicity of the soil, this natural site is almost bare of vegetation. Therefore, in order to promote plant growth, biochar and digestate can be used as growth promoters and soil amendments. The aim of this work is to find the optimal doses of biochar and digestate to be mixed with the polluted soil in order to obtain the best performance at stabilizing trace compounds in the soil. The experiment compiles 9 sets of different combinations of the substrates following an optimised statistical design. In every set, plants were grown in polluted-mixed soil, harvested, and analysed to estimate the biomass content, enzymatic activity and the concentration of trace compounds by Inductively Coupled Plasma (ICP). Soil pore water was analysed as well. Results have shown that combining 85.4% v/v of digestate and 34.1 % v/v of biochar, it is obtained the best performance at reducing their availability trace elements (TEs) from soil pore water, it was found as well that digestate promotes the decrease of the concentration of TEs in soil pore water and also it affects the enzymatic activity by being a possible factor reducing stress in plants.

Keywords

Biochar, Phytostabilization, Dittrichia viscosa, Digestate, Polluted soil

Language used: English

Date on which the thesis was submitted / produced: 20. 4. 2017

Thesis defence

• Supervisor: Mgr. Lukáš Trakal, Ph.D.

Czech University of Life Sciences Prague

Faculty of Environmental Sciences

Master programme / field:
Tropical Agriculture / Sustainable Rural Development in the Tropics and Subtropics