What is it about?
Three different types of low cost soil amendments, namely, EDTA, elemental S and N-fertilizer, were investigated with Vetiver grass, Vetiveria zizanioides (Linn.) Nash growing under highly mixed Cd–Pb contamination conditions. A significant increase (p < 0.05) in Cd and Pb accumulation were recorded in the shoots of all EDTA and N-fertilizer assisted treatments. The accumulation of Cd in 25 mmol EDTA/kg soil and 300 mmol N/kg soil showed relatively higher translocation factor (1.72 and 2.15) and percentage metal efficacy (63.25 % and 68.22 %), respectively, compared to other treatments. However, it was observed that the increased application of elemental S may inhibit the availability of Pb translocation from soil-to-root and root-to-shoot. The study suggests that viable application of 25 mmol EDTA/kg, 300 mmol N/kg and 20 mmol S/kg soil have the potential to be used for soil amendment with Vetiver grass growing under contaminated mixed Cd–Pb soil conditions.
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Why is it important?
The Vetiver grass, Vetiveria zizanioides (Linn.) Nash is a fast growing and easily available in Malaysia as well as many other tropical and sub-tropical countries in the Asia-Pacific region. Vetiver grass has been widely studied over the years and showed good phytoremediation properties for heavy metal accumulation. However, most of the past studies have solely performed to investigate the phytoextraction properties of Vetiver in a single metal contaminated soil condition. There are currently no robust studies that have been examined the comparative and empirical assessment of mixed heavy metals (specifically on Cd-Pb) accumulation in Vetiver grass. Both of the Cd and Pb metals are highly hazardous metals even at low concentration level. And unlike other types of pollution, soil pollution by Cd and Pb metals are often being persistent and stay much longer in the soils as compared to air and water elements.
Perspectives
In this study, we have reported on the metal tolerance, phyto-accumulation properties and the influence of different types of low cost soil amendments in Vetiver grass growing under the highly contaminated mixed Cd-Pb soil condition. The translocation and concentration of heavy metals accumulated in Vetiver were then evaluated based on several phyto-assessment parameters such as tolerance index, biological concentration factor, biological accumulation coefficient, translocation factor and metal uptake efficacy. In our study, the results showed that Vetiver grass has relatively good tolerance responses to survive under the highly mixed Cd-Pb contaminated soil condition. We also discovered that the application of low cost soil amendments able to increase both Cd and Pb metal accumulation. The application of 25 mmol of EDTA, 300 mmol of N-fertlizer and 20 mmol of elemental Sulfur are the most promising soil amendments with Vetiver grass for phytoremediation under the highly contaminated mixed Cd-Pb soil conditions.
Assistant Professor Dr Chuck Chuan Ng
Xiamen University Malaysia
Read the Original
This page is a summary of: Effects of Different Soil Amendments on Mixed Heavy Metals Contamination in Vetiver Grass, Bulletin of Environmental Contamination and Toxicology, September 2016, Springer Science + Business Media,
DOI: 10.1007/s00128-016-1921-5.
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