1. Coordinating teacher: Prof. Dr. Ing. Simina Daniela ȘTEFAN
Polytehnic University of Bucharest
Faculty of Applied Chemistry and Material Science
Phytoremediation- the most effective method of remediating environmental factors using plants
Student:
Iuliana Adriana PREDOIU
Coordinating teacher:
Prof. Dr. Ing. Simina Daniela ȘTEFAN

2. Content: I. Phytoremediation II. How it works III. Soil pollution
IV. Heavy metals
V. Different phytoremediation mechanisms
VI. Plants examples
VII. Advantages
VIII. Disadvantages
Bibliography

3. I. Phytoremediation Phyto- plant remedium- restoring balance
defined as „the effecient use of plants for the remove, detoxify or immobilise environmetal contaminants in a growth matrix (soil, water, or sediments) through biological, chemical or physical plant activites and processes of the plants”

4. Phytoremediation is an in situ remediation technology that utilises the inherent abilites of living plants.
The mechanisms and efficiency of phytoremediation depend on the type of contaminant, bioavailability and soil properties.
The root system provides an enormus surgace area that absorbs and accumulates the water and nutrients essential for growth, as well as other non-essential contaminants.

5. Depositing contaminants in roots, sterling or leaves;
II. How it works?
Some plants are capable of removing or to descompose harmful chemicals from the ground when their roots take water and nutrients from contaminating soil, sediments and groundwater.
Plants can help clean contaminants as deep as their roots, which can go through natural processes to:
Depositing contaminants in roots, sterling or leaves;
Converted to less harmful chemicals in the plant or more frequently in the root area.

6. III. Soil pollution
Soil pollution is defined as the build-up in soils of persistent toxic compounds, chemicals, salts, radioactive materials, or disease causing agents, which have adverse of xenobiotic (human-made) chemicals or other alteration in the natural soil environment.
The most common chemicals involved are petroleum hydrocarbons, polynuclear aromatic hydrocarbons (such as naphthalene and benzo(a)pyrene), solvents, pesticides, lead and other heavy metals.
The soil close to Yangzong Lake, soutwest China’s Yunnan Province was seriously polluted by Arsenic in 2009.

7. IV. Heavy metals
Heavy metals are metallic chemical elements having atomic weight between and , and a specific gravity greater than about 5.0 g/cc. They are toxic, can damage living things at low concentrations and tend to accumulate in the food chain. The most common heavy metals contaminants are: As, Cd, Cr, Cu, Hg, Pb and Zn.
Chronic problems associated with long-term heavy metals exposures are:
Arsenic – skin poisoning, and central nervous system
Cadmium – affects kidney, liver and GI tract.
High levels of metals in soil can be phytotoxic. Poor plant growth and soil caused by mental toxicity can lead to metal mobilization in runoff water and subsequent deposition into nearby bodies of water. Furthermore, bare soil is more susceptibile to wind erosion and spreading of contamination by airbone dust.

8. V. Different phytoremediation mechanisms

9. VI.Plants examples
Many plants, such as mustard, alpine pennycress and gallop, have proven to be successful in over-contaminating contaminants at toxic waste sites.
Pennycress alpine
Plant that has the role of tolerance and raising toxins in the soil. Can absorb high levels of cadmium and zinc from the soil. When compost is applied to contaminated soil, phytotoxicity decreases even more.

10. For the decontamination of a lead-contaminated soil, a Brassica Juncea crop can be used with good results under the conditions of synthetic EDTA-type modifications. Lead concentrations in plant tissues are directly proportional to lead concentrations in the soil.
Citric acid has the best ability to mobilize uranium from the soil and determine its absorption into Brassica juncea plant tissues.

11. Citric acid has the best ability to mobilize uranium from the soil and determine its absorption into Brassica juncea plant tissues.
The plants of the Arabidopsis family, Nicotiana tabacum, have good tolerance to metal ions, but especially to Zn.

12. VII. Advantages
Is less disturbing to the environment and does not involve waiting for new plant communities to recolonize the site
No storage space is required
Is more likely to be aesthetically accepted by the public than traditional methods
Avoid excavation and transport of polluted materials, thus reducing the risk of spreading contaminants.

13. VIII. Disadvantages
Slow growth and low biomass require a long-term commitment
Not possible to completely prevent the leaching of contaminants into the groundwater
The survival of the plants is affected by the toxicity of the contaminated land and the general condition of the soil
Bio-accumulation of contaminants, especially metals, into the plants which then pass into the food chain, from primary level consumers upwards and/or requires the safe disposal of the affected plant material.

14. Bibliography:
„Phytoremediation: green techonology for the clean up of toxic metals in the environment”, Braz. J. Plant Physiol. Vol.17 no. Londrina Jan/Mar.2005