1. Summary of knowledgeSince about 10 years, serious problems of pollution caused by industrialisation and uncontrolled urbanisation appeared in numerous regions of Vietnam. Peripheries of big cities such HCMC are particularly affected.
Waste of plants, traffic on big road led to accumulation of big amounts of toxins in the air, soil and waters.
In Binh Duong Province, many industrial zones have been created, with more or less environment respectful plants. The frightening level of pollution led local authorities to impose strict rules for waste treatment and waste water. Next to those regulations, (clean technologies, non-polluting plants, paying polluter principle), means must be implemented to clean up fields already gravely contaminated.
One of the modern and environmental resolutions to clean up soils consists in using plant; it is what we call phytoremediation. This method is increasingly used due to its effectiveness, its lower expense compare to other chemical or physical methods and without disadvantageous consequences to the environment. This technique helps landscape amelioration without particular efforts.
Phytoremediation is a biological method to restore polluted soils by using plants which are able of hyper accumulation, particularly of heavy metals. It is a new technology very interesting by its potential market.
2. Research ObjectivesStudy consisted in finding plants able to resist lead pollution of soils, providing an important biomass and fast integration to the landscape.
3. Implemented MeansTo make experiments in order to put in practise the training of USN students in this area. Recognition was done in an industrial zone contaminated by lead (plant of batteries). Plants resistant to pollution have been identified. Experiments in pot have made possible the identification of hyper accumulator characteristics of 2 specimens.
Notice absorbency by analyses of soil, roots, branches and leaves
Select hyper accumulator by considering: fastness development, biomass production and environmental character of each plant.
4. Established partnerships
- Environment services of HCMC, of Binh Duong and Dong Nai Provinces.
- The University of Agriculture and Forest of Thu Duc
- The Soil and waters biology Laboratory in Paris XII University
5. Results
Research activities identify two plants able to absorb lead in polluted soils :
1. Le Lantana camera, L ; Verbenaceae, has the characteristic requested for phytoremediation :
- Lead accumulation capacity more than 10 000 ppm
- Fast growing to provide a big biomass
- Nice multicoloured flowers in the landscape that depollute soils at the same time.
- Maximum leaden Content is localized in roots
- Between a content of a lead acetate to 1000 ppm than 7000 ppm , the more soil is contaminated, the more the plant can fix lead.
- The plant can fix lead in first 24h following the treatment
2. Bamboo fills these last criteria perfectly. First experiments showed that one “Bambusa sp.” can resist to heavy metal pollution. Using bamboo gives no production of secondary waste what corresponds to the criterion of sustainable development.
- lead accumulation capacity more than 1000 ppm
- fast growth to provide a important biomass
- maximum leaden content localized at roots level
Student training in the project :
- 3 MA of Environment Biotechnology of USN
- 1 thesis in France (Orsay)
- 1 Master 2 in Paris XII
6. Publications1. Diep thi My Hanh, Pham thi Thanh Loan, Nguyen Giang Son, 2005. Etude de la capacité d’absorption du Plomb par le Lantana camara L. en ajoutant EDTA. Revue Bioechnologie, vol 3, n°4, p. 503- 508.
2. Diep thi My Hanh, E. Garnier Zarli, 2007. Lantana camara, L, plante d’accumulateur de Plomb dans les sols pollués, vol 10, n° 1, p. 13-23
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