Phytoremediation of heavy metal contaminated soil using different plant species

A pot experiment was conducted to compare the plant biomass accumulation and heavy metal (HM) uptake by plant species grown in HM contaminated soils. The shoot dry weights of Eucalyptus camaldeulensis, Medicago sativum, and Brassica juncea grown in contaminated soils were reduced by 8, 5, and 3-fold, respectively, compared to the same plants grown in control soil. The Pb concentration in the shoots of M. sativum, E. camaldeulensis and B. juncea grown in contaminated soil was 8.7, 11.0, and 8.8-fold, respectively, higher than Pb concentration in plants grown in control soils. M. sativum and E. camaldeulensis accumulated higher Zn concentrations in roots (71 and 86 mg kg-1) and shoots (49 and 47 mg kg-1), respectively. Zn concentrations in the roots of M. sativum, E. camaldeulensis and B. juncea were higher than in the shoots by a factor of 1.4, 1.8, and 1.3-fold, respectively. The highest Cu concentration (81 and 37 mg kg-1 dwt) was obtained in root and shoot of M. sativum grown in contaminated soil, while the highest Cr concentration (133.9 mg/kg dwt) was determined in the root of E. camaldeulensis. This suggests that E. camaldeulensis was the best candidate species for phytoremediation of HM contaminated soils.Keywords: Phytoextraction, Roadside soil, Heavy metal, Brassica juncea, Medicago sativum, Eucalyptus camaldeulensi

The impact of variation in chemical and physical properties of PFA and BPD semi-dry cement paste on strength properties

The effect of Pulverised Fuel Ash (PFA) and By-Pass-Dust (BPD) in ternary semi-dry cement pastes was reported. As well as this, the variability over 6 months in chemical composition and particle distribution was reviewed to determine impact on strength. The addition of BPD in ternary pastes resulted in a reduced strength when combined with PFA. PFA and BPD samples obtained over a 6 month period showed variability in both chemical composition and particle distribution. For PFA, it was reported that at 14 days the particle size distribution had greatest impact on strength and at 28 days the SiO2 content had greatest impact. The high variability in BPD particle size distribution resulted in finer particles achieving the greatest strength