Abstract:
Phytoremediation has emerged as a plant-based and cost-effective alternative to remediate
heavy metal contaminated soils. Although this technique is widely known, a significant study
has not been reported yet to find out a potentially capable plant to clean Cr contaminated
soils. In studies carried out by our group, six plant species (Vernonia cinerea, Tridax
procumbens, Sphagnaticola trilobata, Talinum triangulare, Clitoria ternatea and Vernonia
zeylanica) have been tested under Cr contaminated conditions and identified T. triangulare
(Ceylon spinach) with comparatively higher tolerance to Cr with relatively higher biomass
than other plants under contaminated conditions. The aim of this study was to compare the
phytoremediation potential of T. triangulare towards Cr for various soil types under Cr
contamination conditions. Pot experiments were carried out using four different types of soils
(sand, loamy sand, clay and laterite) under Cr contamination conditions (treatments with 200
and 300 mg of Cr/ kg dry soil). Plants were harvested at 60 days of growth and Cr uptake by
plant shoot and root were separately analysed by atomic absorption spectrometry.
The Cr uptake by T. triangulare under different soil types with maximum contaminated
conditions of Cr (300 mg/kg) were analysed (ANOVA, p < 0.05) and showed no significant
difference between loamy sand and sandy soil with the mean value of 109.30 (±18.45) mg kg-
1 and 136.00 (±34.70) mg kg-1 respectively and also no significant difference between
Laterite and Clay with the mean value of 36.26 (±6.12) mg kg-1 and 43.44 (±4.29) mg kg-1
respectively. The results of this study indicated that, Cr uptake capacity and the tolerability of
T. triangulare significantly change with soil types. Even though T. triangulare shows to be
capable of habituation in different soils, its Cr uptake capacities varies significantly. T.
triangulare shows potential of being introduced to different terrestrial environments to
remediate Cr. However, future study of the plant in different soil environments is suggested.
