In the agricultural regions of Burkina Faso, urban solid waste fertilizers were usually applied. This activity is likely to contaminate the soils and expose populations to serious diseases. This study aims to assess r...In the agricultural regions of Burkina Faso, urban solid waste fertilizers were usually applied. This activity is likely to contaminate the soils and expose populations to serious diseases. This study aims to assess rate of heavy metal (Cd, Cu, Mn, Pb, Zn, Ni, Cr) contamination in both agricultural lixisol and vertisol and to evaluate the removal efficiency of heavy metals using Vetiver grass on different two mixed heavy metal contaminated soils. A pot experiment was conducted to compare the metal accumulation and overall efficiency of metal uptake by different plant parts (roots and shoots) on both tropical soils. After 3 and 6 months growing on laboratory conditions, Vetiver grass plants were harvested and heavy metal concentrations in shoot and root parts determined by Inductively Coupled Plasma - Atomic Emission Spectroscopy. The results indicate that at 3 and 6 moths, the shoot and root concentrations of heavy metals in Vetiver grass harvested in lixisol were higher than vertisol. For different plant parts, all metal concentrations were higher in root than in shoot, except Cu and Pb. At the 3 and 6 months, the BCF values > 1 for Cd, Cu and Zn in both soils showed Vetiver grass as an effective phyto-stabilizer for these metals. However, the TF values > 1 for Cd (lixisol), Mn, Zn Ni and Cr (vertisol) indicated the efficiency of Vetiver for phytoextraction. The results of this study showed that Vetiver is more effective in lixisol</span><span style="font-family:"">,</span><span style="font-family:""> but it can be used for remediation of both studied tropical soils from agricultural region of Burkina Faso. Nevertheless, considering the special limitations of the experimental conditions, further field monitoring is necessary to demonstrate the phytoremediation efficiency of Vetiver in agricultural soils under the climatic conditions of Burkina Faso.展开更多
Rainfall-induced slope failures commonly occur in residual soil slopes.Slope failures are triggered by the reduction in soil strength.This is attributed to the decrease in soil suction due to rainwater infiltration.Sl...Rainfall-induced slope failures commonly occur in residual soil slopes.Slope failures are triggered by the reduction in soil strength.This is attributed to the decrease in soil suction due to rainwater infiltration.Slope covers like capillary barrier system and vegetative cover are effective methods that can be used to prevent rainfall-induced slope failures.The capillary barrier system is able to limit the rainwater infiltration,and vegetation can contribute to the increase in soil strength.Vetiver grass is widely planted in tropical and subtropical areas of the world for soil and water conservation.This study investigates the characteristics of unsaturated soil slope covered with capillary barrier system and Vetiver grass in comparison with the original slope through numerical analyses and field measurements.The analyses were carried out under the advanced,normal,and delayed rainfall patterns.The results of the analyses indicated that the capillary barrier system played a more significant role than the Vetiver grass in maintaining slope stability,although both the capillary barrier system and Vetiver grass contributed to the slope stability.In addition,both numerical analyses and field measurements showed that under the delayed and normal rainfall patterns,when antecedent rainwater infiltration could increase the soil moisture,the capillary barrier system performed much better compared to Vetiver grass in maintaining soil matric suctions and slope stability.展开更多
文摘In the agricultural regions of Burkina Faso, urban solid waste fertilizers were usually applied. This activity is likely to contaminate the soils and expose populations to serious diseases. This study aims to assess rate of heavy metal (Cd, Cu, Mn, Pb, Zn, Ni, Cr) contamination in both agricultural lixisol and vertisol and to evaluate the removal efficiency of heavy metals using Vetiver grass on different two mixed heavy metal contaminated soils. A pot experiment was conducted to compare the metal accumulation and overall efficiency of metal uptake by different plant parts (roots and shoots) on both tropical soils. After 3 and 6 months growing on laboratory conditions, Vetiver grass plants were harvested and heavy metal concentrations in shoot and root parts determined by Inductively Coupled Plasma - Atomic Emission Spectroscopy. The results indicate that at 3 and 6 moths, the shoot and root concentrations of heavy metals in Vetiver grass harvested in lixisol were higher than vertisol. For different plant parts, all metal concentrations were higher in root than in shoot, except Cu and Pb. At the 3 and 6 months, the BCF values > 1 for Cd, Cu and Zn in both soils showed Vetiver grass as an effective phyto-stabilizer for these metals. However, the TF values > 1 for Cd (lixisol), Mn, Zn Ni and Cr (vertisol) indicated the efficiency of Vetiver for phytoextraction. The results of this study showed that Vetiver is more effective in lixisol</span><span style="font-family:"">,</span><span style="font-family:""> but it can be used for remediation of both studied tropical soils from agricultural region of Burkina Faso. Nevertheless, considering the special limitations of the experimental conditions, further field monitoring is necessary to demonstrate the phytoremediation efficiency of Vetiver in agricultural soils under the climatic conditions of Burkina Faso.
文摘Rainfall-induced slope failures commonly occur in residual soil slopes.Slope failures are triggered by the reduction in soil strength.This is attributed to the decrease in soil suction due to rainwater infiltration.Slope covers like capillary barrier system and vegetative cover are effective methods that can be used to prevent rainfall-induced slope failures.The capillary barrier system is able to limit the rainwater infiltration,and vegetation can contribute to the increase in soil strength.Vetiver grass is widely planted in tropical and subtropical areas of the world for soil and water conservation.This study investigates the characteristics of unsaturated soil slope covered with capillary barrier system and Vetiver grass in comparison with the original slope through numerical analyses and field measurements.The analyses were carried out under the advanced,normal,and delayed rainfall patterns.The results of the analyses indicated that the capillary barrier system played a more significant role than the Vetiver grass in maintaining slope stability,although both the capillary barrier system and Vetiver grass contributed to the slope stability.In addition,both numerical analyses and field measurements showed that under the delayed and normal rainfall patterns,when antecedent rainwater infiltration could increase the soil moisture,the capillary barrier system performed much better compared to Vetiver grass in maintaining soil matric suctions and slope stability.
