Table Of ContentPHYTOREMEDIATION POTENTIAL OF AROMATIC
GRASSES (LEMON GRASS, VETIVER) VIS A VIS RAYA
FOR CADMIUM CONTAMINATED SOILS
Thesis
Submitted to the Punjab Agricultural University
in partial fulfillment of the requirements
for the degree of
MASTER OF SCIENCE
in
SOIL SCIENCE
(Minor Subject: Chemistry)
By
Dilip Kumar Pal
(L-2010-A-98-M)
Department of Soil Science
College of Agriculture
© PUNJAB AGRICULTURAL UNIVERSITY
LUDHIANA-141 004
2013
CERTIFICATE – I
This is to certify that the thesis entitled, “Phytoremediation potential of aromatic
grasses (lemon grass, vetiver) vis a vis raya for cadmium contaminated soils” submitted
for the degree of M.Sc. in the subject of Soil Science (Minor Subject: Chemistry) of the
Punjab Agricultural University, Ludhiana, is a bonafide research work carried out by Dilip
Kumar Pal (L-2010-A-98-M) under my supervision and that no part of this thesis has been
submitted for any other degree.
The assistance and help received during the course of investigations have been fully
acknowledged.
(Major Advisor)
Dr. MPS. KHURANA
Senior Soil Chemist
Department of Soil Science
Punjab Agricultural University,
Ludhiana- 141004 (India)
2
CERTIFICATE- II
This is to certify that the thesis entitled, “Phytoremediation potential of aromatic
grasses (lemon grass, vetiver) vis a vis raya for cadmium contaminated soils” submitted
by Dilip Kumar Pal (L-2010-A-98-M) to the Punjab Agricultural University, Ludhiana, in
partial fulfilment of the requirements for the degree of M. Sc. in the subject of Soil Science
(Minor Subject: Chemistry) has been approved by the Student’s Advisory Committee along
with the Head of Department after an oral examination of the same.
____________________ __________________
Head of the Department Major Advisor
(Dr. U S Sadana) (Dr. M P S Khurana)
_________________________
Dean, Post-Graduate Studies
(Dr. Gursharan Singh)
3
ACKNOWLEDGEMENTS
First of all, I bow my head to “AKAL PURKH” the ALMIGHTY by whose
kindness I have been able to clear another chapter of my life.
Words are compendious in expressing my profound sense of gratitude to my
revered Major Advisor Dr. M P S Khurana, Sr. Soil Chemist, Department of Soil
Science, Punjab Agricultural University, Ludhiana, for his constant guidance,
constructive criticism, encouragement and unstinting moral support provided during this
investigation. Working under his expertise has been a great learning experience.
I am highly thankful to the respected members of my Advisory Committee,
Dr. Dhanwinder Singh, Sr. Soil Microbiologist, Department of Soil Science, Dr. Anita
Garg, Chemist, Department of Chemistry, Dr. Rajender Kumar, Assistant Agronomist,
Department of Agronomy and Dr. G S Saroa (Dean PGS Nominee), Sr. Soil Chemist,
Department of Soil Science for their valuable suggestions, continuous support and going
through the manuscript.
I duly acknowledge the research facilities provided by the Head, Department of
Soil Science, Punjab Agricultural University, Ludhiana.
I am falling short of words to express my feelings of obligation toward my
parents Sh. Uma Shankar Pal and Smt. Vimla, who always stand by me during the
testing times of my life. I also thankful to my elder brother Kailash Pati Pal for their
moral support during the period of study. Their everlasting inspiration, support and
affection enable me to face difficult situations in my life.
I am highly thankful to my friends, Rajan, Rajiv, Arun, Lakhvir, Sanjay,
Navneet, Haridarshan, Sooraj, Niraj, Hanu, Dhaked, Pawitar and Daljeet for their
pleasant association and co-operation during the hours of need.
Invaluable help rendered by laboratory and field staff of the Department of Soil
Science is fully acknowledged.
I feel proud to be a part of PAU, Ludhiana where I learnt a lot and spent some
unforgettable moments of my life.
Needless to say, errors and omissions if any are all mine.
Date__________ ____________________
Place: Ludhiana Dilip Kumar Pal
4
Title of the thesis : "Phytoremediation potential of aromatic grasses (lemon
grass, vetiver) vis a vis raya for cadmium contaminated
soils"
Name of the student : Dilip Kumar Pal
and Admission No. L-2010-A-98-M
Major Subject : Soil Science
Minor Subject : Chemistry
Name and Designation : Dr. MPS Khurana
of Major Advisor Sr. Soil Chemist
Degree to be Awarded : M.Sc.
Year of award of degree : 2013
Total pages in thesis : 85+Vita
Name of the University : Punjab Agricultural University,
Ludhiana – 141 004, Punjab, India
ABSTRACT
Environmental pollution due to industrial and agricultural activities had resulted in
considerable increase in heavy metals in all compartments of environment, especially in soils.
Hyper-accumulator plants are needed to be identified to remediate the polluted soils.
Aromatic grasses are known to accumulate nutrient and toxic elements in large amount so
phyto-remediating potential of lemon grass and vetiver are compred with raya. To find out the
best phytoremediating crop screen house studies were conducted with Cd (0, 5, 10, 20, 40, 80
and 160 mg kg-1 soil) and EDTA (0 and 1 g kg-1 soil) on alkaline loamy sand soil. Increasing
rates of Cd application resulted in significant increase in DTPA-Cd which was further
enhanced by EDTA application. Increasing phyto-toxic effect of Cd with its increased
application, consequently caused reduction in dry matter yield of each crop. Vetiver contained
highest content of Cd in both shoots and roots, thus showing its highest accumulation/phyto-
remediating potential among other crops. The roots in all crops were found to accumulate
higher content of Cd as compared to shoots. The yield reduction at 80 mg Cd kg-1 soil was
65.9, 21.5 and 19.8 per cent in raya, lemon grass and vetiver respectively suggesting vetiver
to be the most tolerant crop while raya to be less tolerant whereas lemon grass showed
intermediate tolerance. The upper critical toxic levels of DTPA-Cd in soil was estimated to be
10.3, 21.4 and 24.5 mg kg-1 soil for raya, lemon grass and vetiver respectively while in shoots,
these were 40.7, 138.2 and 180.3 µg g-1 dry matter for 20 % reduction. The relation of Cd
with Cu and Mn was antagonistic while with Fe and Zn, it was synergistic at lower levels but
antagonistic at higher levels. Among various fraction such as Exchangeable + water soluble
(EX + WS), carbonate bound (CARB), Organic bound (OM), Mn-oxide bound (MnOX),
Amorphous Fe-oxide bound (AFeOX), Crystalline Fe-oxide bound (CFeOX) and residual
(RES), EX+WS influenced the bio availability of Cd to greater extent (60 to 84%) compared
to other fraction. Application of EDTA substantially increased EX+WS fraction indicating its
usefulness in enhancing the solubility of this element. The amount of EX+WS fraction left
after the harvest was minimum in vetiver at all levels of Cd application. This quality of
vetiver makes it most suitable candidate for the cleanup of soil contaminated with heavy
metal.
Key words: Cadmium, EDTA, Critical levels, Cd fractions
_____________________ ___________________
Signature of Major Advisor Signature of the Student
5
6
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iv`c coKw vwDw hoieAw, ijs iv`c eI.fI.tI.ey. (EDTA) pwaux nwl hor vwDw hoieAw[ kYfImIAm dI
mwqrw iv`c vwDy nwl PweItotokisk pRBwv ivc vI vwDw hoieAw, ijs kwrn hryk &sl dy s`uky pdwrQ
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im`tI iv`c DTPA-Cd dI auqlI nwzuk p`Dr 10.3, 21.4 Aqy 24.5 im. gRwm iklo-1 rwieAw, lYmn gRws
qy vYtIvr iv`c kmR vwr pweI geI jdoN ik qxy iv`c ieh mwqrw 40.7, 138.2 Aqy 180.3 mweIkRogRwm
gRwm-1 sI [ kfY ImIAm dy Cu Aqy Mn nwl sbMD ivroDI sn jdNo ik Fe Aqy Zn nwl hyTlI p`Dr qy
nyVly pr au~qlI p`Dr qy ivroD vwly sbMD sn[ v`Ko-v`Kry q`qW ijvNy ik qbdIlI vwlw + pwxI iv`c
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(CfeOX) Aqy irizfUAl (RES), EX+WS AMS ny kfY ImIAm dI aupl`bDI nUM dUijAW AMSW dy mukwbly
vDyry (60 qoN 84 pRqISq) pRBwivq kIqw h[Y eI.fI.tI.ey. dI vrqoN EX+WS AMS iv`c cKo w vwDw krdI
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7
CONTENTS
CHAPTER TITLE PAGE NO.
I INTRODUCTION 1-3
II REVIEW OF LITERATURE 4-19
III MATERIAL AND METHODS 20-24
IV RESULTS AND DISCUSSION 25-71
V SUMMARY 72-75
REFERENCE 76-85
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CHAPTER I
INTRODUCTION
In the recent years, the concern has been focused increasingly on environmental
pollution and its impact on human being and animals. Industrial and agricultural activities in
developing countries have led to considerable increase in different environmental
compartments especially in soils over the past decade. Modern agriculture is confronted with
an environmental crisis with major concern being addressed to its long term safety. It is
needed to provide safe food and disposal of feed, respecting environmental quality and
national resources. Degradation of environment by disposal of wastes releasing various toxic
metals is the result of the development in industrial sector. Agricultural lands show elevated
levels of pollutants metals due to various anthropogenic activities such as continuous use of
sewage water largely contaminated with industrial effluents, sewage sludge and fertilizers.
Though effluent is enriched with several useful ingredients as well, such as nitrogen,
phosphorus and potassium, providing fertilizer value to the growing crops but presence of
heavy metals such as cadmium affects the crop negatively resulting in loss of yield (Rattan et
al 2005 and Khurana et al 2003). Heavy metal contamination is of particular concern due to
the growing number of sites that are contaminated and the serious health problems associated
with heavy metal toxicity. The crops growing on sewage irrigated soils invariably contained
higher amounts of heavy metals as compared to the tube-well irrigated soils (Brar et al 2002
and Khurana et al 2003). Among the pollutants element, cadmium (Cd), a commulative
poison, is recognized as an extremely significant pollutant due to its high toxicity even at low
exposure and relatively large solubility in water (Pinto et al 2004). This has led the
International Food Standards Organization, Codex Alimentarious Commission to propose a
0.1 mg Cd kg-1 limit for cereals, pulses and legumes. The maximum tolerable intake of
cadmium for humans recommended by FAO/WHO is 70 ug day -1.
Sewage irrigated soils contain higher amounts of heavy metals as compared to the
tube-well irrigated soils. These metals due to their high residence time remain in the soils in
dangerous proportion and thus have implications on human and animal health (Aulakh et al
2009 and Mitra and Gupta 1999). Physical and chemical technologies have been used to
ameliorate heavy metal contaminated soils. Physical methods and evacuation of polluted soils
and its disposal to land fill sites are quite expensive. In chemical methods, the amount of
heavy metal fraction available to the plants has to be reduced which means they have to be
immobilized and the equilibrium between soluble and insoluble fraction is intentionally
shifted towards more insoluble form. This can be achieved either by increasing soil pH or
causing precipitation or forming insoluble complexes. Nevertheless, the heavy metals remain
in soil. Therefore, the result of chemical remediation is not decontamination but stabilization
where the metals are transferred to inactive form. Thus this approach has deleterious effect on
microbiological, physical and chemical properties which results in unforeseen shift in
chemical equilibrium in the soil. They may cause severe disturbances in the soil profile of the
area or run the risk of further contamination. Information regarding the amelioration of the
soils contaminated with heavy metals particularly cadmium with some cost effective
technology is lacking.
More recently, increasing attention has been given to the plant based technology
(phytoremediation) to remediate heavy metal contaminated soils (McGrath et al 1993). It is
the emerging technologies which offers cost effective and safe alternative to conventional
soil clean up techniques by using the ability of some plants to absorb and accumulate
significantly very high concentration of these heavy metal ions. It is typically slower than
chemical or removal techniques due to the growing season of the plants, but does not
interfere with soil profile. In the phytoremediation process, several sequential crops of
selected plant species can be cultivated to reduce the concentrations of heavy metals in
contaminated soils to environmentally acceptable levels (Padmavathiamma and Li 2007 and
Jaldia et al 2009). Heavy metals can be translocated to above ground plant parts. The metal-
rich plant material may be safely harvested and removed from the site without extensive
excavation, disposal costs and loss of top soil associated with traditional remediation
practices (Blaylock et al 1997). A viable and remunerative option could be the cultivation
of non-edible crops, which are economically remunerative as well like cut flower, aromatic
and and medicinal plants (Lal et al 2008). Assessment of the relative accumulation in the
aerial and underground parts still remains to be elucidated. Synthetic chelates such as
EDTA, DTPA, HEDTA and EGTA has been used in soils to increase the phytoextraction of
heavy metals from soils (Kos et al 2003). An increase in heavy metals (Pb, Zn and Cd)
mobilization from soils has been observed with applied EDTA (Gray et al 2000 and
Greman et al 2001). Studis have indicated that EDTA made the cadmium more available to
the plants and lowered the Cd content of the soil. Results from these studies suggested that
with careful management, chelate assisted phytoextraction may provide a still more cost
effective decontamination strategy.
Further, sequential extraction procedures are essentially needed to identify the solid
phases of heavy metals responsible for bioavailability. Once, these heavy metals are
incorporated into the soil, their extractability decreases with time indicating a possible change
of their forms in the soil (Bell et al 1991). If the crop is planted following the application of
heavy metals, extractability depends on the type of plant species and the change in chemical
form which may influence the uptake by plants and help to reduce the toxicity. Therefore the
present study was planned with the following objectives:
2
Description:This is to certify that the thesis entitled, “Phytoremediation potential of aromatic grasses (lemon grass, vetiver) vis a vis raya for cadmium contaminated
