Fluoride remediation using floating macrophytes

Communications in Plant Sciences (January-June 2014) 4(1-2): 23-33

ISSN 2237-4027

www.complantsci.wordpress.com

Manuscript accepted on April 04, 2014 / Manuscript published online on April 29, 2014

Fluoride remediation using floating macrophytes

Naba Kumar Mondal*, Ria Bhaumik, Uttiya Dey, Kartick Chandra Pal, Chittaranjan Das, Anindita Maitra and

Jayanta Kumar Datta Department of Environmental Science, The University of Burdwan, Burdwan

ABSTRACT

Six aquatic macrophytes, such as Pistia stratiotes, Ceratophyllum demersum, Nymphoides indica,

Lemna major, Azolla pinnata, and Eichhornia crassipes were considered for remove fluoride from

aqueous solution. Five different concentrations (10, 30, 50, and 100 ppm) of fluoride solution were

taken in 1 L plastic container. Fixed weight (20 g) of macrophytes along with 500 ml fluoride

solution was taken in each plastic container for 72 hours observation. Results demonstrated all the

macrophytes show highest fluoride removal during 24 h to 48 h, but after 72 h their efficiency

reduced drastically. The species N. indica showed better removal efficiency than other experimental

macrophytes. In general, pigment measurement data indicated higher concentration at 72 h.

However, Pistia sp. showed higher concentration of pigmentation at intermediate time interval

(48 h). Higher level of dry weight to fresh weight ratio was recorded for L. major and A. pinnata at

all concentrations, excepting at 10 ppm. In addition, all macrophytes showed lower RGR at higher

concentration. Isotherm study indicated that macrophyte C. demersum is a good fitted with

Freundlich and Langmuir isotherm whereas L. major with Langmuir isotherm during 24 hours.

Keywords: Aquatic macrophyte, Fluoride, Adsorption, Pigment, Growth ratio, Biochemistry

_______________________________ *Corresponding author E-mail: [email protected] Phone: +94 34545694

Communications in Plant Sciences (2237-4027) Com Plant Sci 4(1-2): 23-33 (Jan-Jun 2014)

24 Mondal et al. 2014. Fluoride remediation using floating macrophytes.

INTRODUCTION

Control of pollution is one of the prime priorities in our

societies (Khataee et al. 2013). Among the non-metals,

fluorine is one of the most abundant elements in the

continental crust (Hu et al. 2012). Due to high electro

negativity, fluorine cannot exist in free elemental state

in nature (Camargo 2003). The most predominant

species of fluorine present in natural water as free

anion (F-), undissociated hydrofluoric acid (HF) and its

various complex forms (Pitter 1985). The natural level

of fluoride in uncontaminated fresh surface water is

<5 μM, although industrial activities can increase

concentrations to toxic levels. Substantial amount of

fluoride can cause fluorosis and subsequently it cause

global problem in many parts of the world (Msonda et

al. 2007). It is most commonly found in water-stressed

regions (Rao and Devada 2003, Suthar et al. 2008).

Fluoride is present in sea water as a major component

and concentration ranges from 1-3 mg kg-1

(Wilson

1975). Accumulation of fluoride and consequent

impairment of normal functioning occurs both in plants

(McCune et al. 1964, Weinstein and Alscher-Herman

1982), and animals (Hemens and Warwick 1972,

Bogin 1976). Among marine organisms, red algae are

known to accumulate the highest levels of fluoride

(Young and Langille 1958). Rao and Indusekhar

(1989) reported the presence of 11.35-20.04 mg kg-1

fluoride in red algae as compared to 4.78-17.82 and

3.02-18.86 mg kg-1

F in brown and green algae,

respectively. In general, cyanobacteria are highly

sensitive to fluoride, whereas green algae appear

almost resistant to F concentrations up to 10 mM. It

has been suggested that the ambient fluoride

concentrations observed in nature should have

minimal effects on indigenous algal flora.

Though voluminous information is available on the

impact of fluoride on higher plants and animals,

comparatively few studies have been reported on

fluoride uptake by aquatic macrophytes. Aquatic

macrophytes play a significant role in maintaining

water quality. There has been a great deal of interest

in the use of floating aquatic macrophytes to reduce

the concentration of noxious phytoplanktons in the

effluent from stabilization ponds and to remove

nitrogen and phosphorous from the water (Steward

1970). Aquatic floating macrophytes take up inorganic

nutrients mainly by the roots, although uptake through

the leaves may also be significant. Members of free

floating duckweeds (Lemnaceae), namely Lemna

minor, Lemna gibba, Wolffia arrhiza, and Azolla pinnata

have shown potential usefulness in the treatment of

eutrophicated water system (Sutton and Ornes 1975).

Growing evidence support that macrophytes has

immense potentiality to remove pollutant from the

aqueous medium. But not a single study highlighted to

use six macrophytes and their potentiality to remove

fluoride from surface water.

Recently, several works have demonstrated the

potential of wetland plants in aquatic phytoremediation,

a process that includes rhizofiltration, phytofiltration,

and constructed wetlands (Raskin et al. 1994, Brooks

and Ribnson 1998, Qian et al. 1999, Dushenkov and

Kapulink 2000). Due to the relative novelty of the

technology, much of the current research is still aimed

at the selection of wetland preference to high

environmental concentrations of the pollutant species,

based on the type of elements(s) to be remediated, the

local environmental and geographical conditions as

well as the removal capabilities of the plant (Zurayk et

al. 2001).

There is an evidence that aquatic plants can hyper

accumulate trace elements in their tissues when grown

in polluted water (Jain et al. 1989, Dunbabain and

Bowmer 1992, Huebert and Shay 1993). Duckweed (L.

minor) and water valvet (A. pinnata) have been shown

to bioconcentrate metals such as Fe and Cu by up to

78 times the concentrations in the waste water (Jain et

al., 1989). Pinto et al. (1987) demonstrated that water

hyacinth would remove silver from industrial waste

water for subsequent recovery with high efficiency in a

fairly short time. Water hyacinth has been used

successfully in waste water treatment systems to

improve the quality of water by reducing the levels of

organic and inorganic nutrients (Brix 1993, Delgado et

al. 1995) and readily reducing the level of heavy

metals in acidmine drain-age water (Falbo and Weaks

1990).

So, the knowledge of the capabilities of different

wetland plant species to absorb and transport trace

elements under different conditions is important to

know. The objective of this resource was to verify the

capacity of using of six macrophytes for fluoride

remediation.

MATERIAL AND METHODS

Sample collection. Samples were collected from a

stagnant water body, Golapbug campus, the University

of Burdwan near Botany Department. The sample

collection was done by using plastic packets. Six

varieties of macrophytes (Table 1) were collected

namely Pistia stratiotes (M1), Ceratophyllum

demersum (M2), Nymphoides indica (M3), Lemna

major (M4), Azolla pinnata (M5), and Eichhornia

crassipes (M6).

Experimental setup. A stock solution of 100 ppm of

fluoride was made by using anhydrous NaF in double

distilled water in a 1 liter volumetric flask and making



the volume up to the mark. From this stock solution

10 ppm, 30 ppm and 50 ppm concentrated solution

was made by dilution (each of 500 mL). The six

macrophytes were collected from target placed and

cleaned with distilled water for removal of dirt and

soluble substance. Then the water was soaked using

tissue paper and weighted and the initial weights of

them were noted. After socking water, each

macrophyte then placed in to different concentrated

solution of fluoride and solution fluoride level was

noted after 24 h, 48 h, and 72 h intervals. The fluoride

was measured by following standard method (APHA

1998). The macrophytes (fed with fluoride solution of

different concentrations) were kept for observation in

plastic (Terson made) bowl.

Table 1. Information on the species used in this study.

Family Name Scientific Name Common Name

Araceae Pistia stratiotes Water letuce

Pontederiaceae Eichhornia crassipes Waterhyacinth

Menyanthaceae Nymphoides indica Water snowflake

Ceratophyllaceae Ceratophyllum demersum Hornwort

Araceae Lemna major Duckweed

Azollaceae Azolla pinnata Water valvet

Plant material. Six floating macrophyte were collected

from natural ponds and grown in 3% Hoagland’s

nutrient medium (Hoagland et al. 1950) in the laboratory

under controlled conditions (27 ± 20C, 45 µmol m

-2 s

-1

photon flux intensity, 10 h/daylight period). The final pH

of the solution was 6.5. Two-week-old macrophytes

from the stock culture were used in the experiments.

Phytoaccumulation and phytotoxicity. The 3%

Hoagland’s nutrient medium was supplemented with

four normal concentrations (10, 30, 50, and 100 mg L-1

)

of F prepared from NaF. The final pH of the solution

was 6.8. 20g of six selected macrophytes were

inoculated into each spherical container (Tarson made,

diameter 22 cm) containing various solution of F-.

Founds cultured in the nutrient medium without F-

were treated as control. All the experiments were

performed in triplicates. After 24 h, 48 h, and 72 h,

plants from each flash were harvested separately and

analyzed for biomass, chlorophyll, carotenoid, and

F- content.

Total chlorophyll content. Fresh young leaves (0.1 g)

were selected from plants under each treatment at the

last day of the experiment, and washed with de-ionized

water. Leaves were cut into small pieces. Chlorophyll

fractions ‘a’, ‘b’ and total chlorophyll were determined

in the acetone extract (80% v/v) (Arnon 1949)

measured in a spectrophotometer at 645, 652, and

663 nm and the concentration were expressed as mg

chlorophyll g-1

fresh weight by using the following

equations:

1

663 645" "(mgg f.w) [12.7 D 2.69 D ]1000

vwChl a x x x

1

645 663" "(mgg f.w) [22.9 D 4.68 D ]1000

vwChl b x x x

1

652(mgg f.w) D 10001000

vwTotalChl x x

where D = optical density; v = final volume of 80% acetone;

w = weight of sample; f.w. =fresh weight of the sample.

Growth parameters. Fresh weight (FW, biomass) and

dry weight (DW) of all experimental macrophytes were

recorded before starting the experiment and after 10

days of incubation. To measure dry weight, plants

were dried at 80 0C (Cedergreen et al. 2007) up to

constant weight (usually 24h). Relative growth rate

(RGR) was calculated according to the equation

proposed by Hunt (1978):

2 1

2 1

( )W WRGR

T T

where RGR = relative growth rate (gg-1

d-1

), W1 and W2 =

initial and final dry weight, respectively, and (T2-T1) =

experimental period. Growth was compared considering the

control treatment versus treatments. The entire experiment

was run by triplicate. Dry to fresh weight ratio (DW/FW) was

determined according to calculation: dry weight (g)/fresh

weight (g).

Statistical analysis. The observed tabular data were

analyzed statistically by one way ANOVA analysis and

the significant difference between the treatments

means were compared through DMRT test (Panse and

Sukhatme 1967, Gomez and Gomez 1984).

RESULTS AND DISCUSSION

From the entire study it has been found that the

experimental macrophytes (Table 1) showed significant

potentiality with respect to removal of fluoride from

water. The first set of experiment was conducted by

considering 10 ppm solution of F. The removal of

fluoride was recorded after 24 h, 48 h, and 72 h. All the

macrophytes did not show same efficiency for fluoride

removal. Again no macrophyte showed sequential

removal efficiency with time. In all the cases removal

was recorded after 24 h with respect to initial

concentration, but concentration of fluoride was

increased in the solution. This is probably due to the

fact that desorption occurs after 24 h. From the

Figure 1 it is clear that only macrophytes M1 and M6

showed significant removal at 5% level of significance.



10 ppm 30 ppm 50 ppm 100 ppm0

10

20

30

40

50

60

70

80

90

100

c

c

b

b

aa

a

bb

bb

a

% o

f F

rem

oval

Concentrations

B24 hrs

C48 hrs

D72 hrs

(a) Pistia stratiotes (M1)

10 ppm 30 ppm 50 ppm 100 ppm

0

10

20

30

40

50

60

70

80

90

a

a

a

a

c

b

b

bb

bb

c

% o

f F

re

mo

val

Concentrations

B24 hrs

C48 hrs

D72 hrs

(b) Ceratophyllum demersum (M2)


10

20

30

40

50

60

70

80

90

100

c

c

c

aa

a

a

a

b

bb

b

% o

f F

rem

oval

Concentrations

B24 hrs

C48 hrs

D72 hrs

(c) Nymphoides indica (M3)


0

10

20

30

40

50

60

70

80

90

b

b

bb

b

a

a

a

a

c

cc

% o

f F

rem

oval

Concentration

B24 hrs

C48 hrs

D72 hrs

(d) Lemna major (M4)


0

10

20

30

40

50

60

70

80

90

100

c

c

aa

a

a

b

b

bb

b

b

% o

f F r

emov

al

Concentrations

B24 hrs

C48 hrs

D72 hrs

(e) Azolla pinnata (M5)


10

20

30

40

50

60

70

80

90

100

c

bb

b

bb

bb

aa

a

a

% o

f F

rem

ova

l

Concentrations

B24 hrs

C48 hrs

D72 hrs

(f) Eichhornia crassipes (M6)

Figure 1. Percentage of fluoride removal of macrophytes from different concentrations of fluoride solution during different time interval.

At 10 ppm only macrophyte M1 and M6 showed

significant removal performance than other macrophytes

during 24 h (Figure 1 a and f) and at 48 h M6

macrophyte again showed better performance than

others. Again M2, M3, M4, M5, and M6 showed

resorption during 48 h. That means after 48 h

macrophytes did not perform better (Figure 1). At

30 ppm removal performance order was N. indica (M3)

> P. stratiotes (M1) > C. demersum (M2) > L. major

(M4) > E. crassipes (M6) > A. pinnata (M5) during

48 h, although 24 h performance order was

P. stratiotes (M1) > N. indica (M3) > C. demersum

(M2) > A. pinnata (M5) > L. major (M4) > E. crassipes

(M6). Definitely macrophyte M3 showed excellent

performance with different time interval and particularly

this macrophyte absorped more than 99% fluoride

(Figure 1). Therefore N. indica was the best fluoride

absorber. Again at 72 h removal efficiency order was

N. indica (M3) > C. demersum (M2) > P. stratiotes

(M1) > L. major (M4) > E. crassipes (M6) > A. pinnata

(M5). At 50 ppm all macrophytes showed good

performance during 72 h (Figure 1). Although at 48 h



M2, M4, and M5 showed moderate removal

performance (Figure 1 b, d, and e). Macrophytes M1,

M5, and N6 showed good performance during 24 h

(Figure 1 a, e, and f). At 100 ppm similar reduction was

noted during 72 h; although the efficiencies of removal

of fluoride were a little lower than 50 ppm. During 48 h

only M1 showed good performance than other

macrophytes (Figure 1 a).

The fluoride removal efficiencies of different

macrophytes were distinct in different concentrations

with different time intervals. In 10 ppm F- solution M1

and M2 macrophytes showed the highest F- removal at

24 h and 72 h, respectively. But all other macrophytes

showed high fluoride removal efficiency during 48 h in

all concentrations (Figure 1). At higher concentrations

(30 ppm and 50 ppm) all macrophytes showed very

slow fluoride removal efficiency during 24 h and 48 h

than 72 h. But at 100 ppm fluoride solution, all

macrophytes showed higher F- removal efficiency

during first 24 hours compared to 10 ppm, 30 ppm, and

50 ppm solution; although, maximum F- removal

recorded at 72 h for 100 ppm F- solution (Figure 1).

Moreover, isotherm study clearly indicates that only

macrophyte C. demersum (M2) showed good

agreement with Freundlich and Langmuir adsorption

isomer during 24 h, whereas, macrophyte L. major

(M4) showed good agreement with Langmuir isotherm

during 24 h (Table 2). But other macrophytes did not

show any agreement with the isotherm model in any

interval of time. On the other hand the reduction of

biomass (%) was recorded highest in Ceratophyllum

sp. for both 10 pm and 30 ppm fluoride solution.

However at 50 ppm and 100 ppm fluoride solution

showed maximum dry biomass reduction in Pistia sp.

and Nymphoides sp. respectively (Table 3). Similarly

lowest dry biomass reduction was recorded in L. major

at 30 and 50 ppm fluoride solution respectively. But the

Nymphoides sp. and Azolla sp. showed lowest

biomass reduction at 10 and 100 ppm fluoride solution

respectively.

Table 2. Isotherm study during different time interval.

Macrophyte Isotherms 24 h 48 h 72 h

M1 Freundlich Y = 0.6798X-2.3161, R2=0.1614 Y=0.451X-1.854, R

2=0.038 Y=0.589X-0.533, R

2=0.019

Langmuir Y = 36.951X+51.943, R2=0.0023 Y=459.8X+5.333, R

2=0.370 Y=119.2X+0.031, R

2=0.016

Temkin Y = 3.4601X + 2.7183, R2=0.1979 Y=-0.399X+2.836, R

2+0.009 Y=-0.761X+2.170, R

2=0.128

D-R Y = - 2x10-5

X-0.376, R2=0.172 Y=1×10

-5X-2.461. R

2+0.186 Y=5×10

-6X-2.955, R

2=0.025


2=0.248 Y=0.798X-1.838, R

2=0.282

Langmuir Y = -26.468X+108.78, R2=0.8979 Y=708.8X+18.47, R

2=0.506 Y=189.5X-6.083, R

2=0.794

Temkin Y = 0.0168X+3.0615, R2=0.0019 Y=47.41X+2.155, R

2=0.573 Y=1.201X+2.13, R

2=0.057

D-R Y = -7.7015X+123.79, R2=0.0732 Y=-2 × 10

-5X-2.946, R

2=0.269 Y=0.001X-384.8, R

2=0.083


2= 0.334 Y=-0.098-0.94, R

2=0.009

Langmuir Y = 38.64X+158.57, R2=0.3605 Y=299.5X+7.903, R

2=0.716 Y=-6842X+27.51, R

2=0.079

Temkin Y = 0.146X+3.0311, R2=0.1345 Y=2.077X+2.717, R

2=0.120 Y=2.112X+0.702, R

2=0.051

D-R Y =-6966.5X-1865.6, R2=0.1128 Y=1×10

-50X-2.472, R

2=0.369 Y=5×10

-5X-578.8, R

2=0.107


2=0.342 Y=-0.732X-0.47, R

2=0.023

Langmuir Y =5672.2X-57.686, R2=0.9319 Y=646.9X+17.81, R

2=0.467 Y=345.7X+20.2, R

2= 0.015

Temkin Y = 2.3787X-3.1322, R2=0.1524 Y=2.418X+2.916, R

2=0.162 Y=-0.933X+2.445, R

2=0.142

D-R Y=-4×10-5x-3.507, R

2=0.393 Y=2×10

-5X-2.862, R

2=0.269 Y=1×10-5=X-3.478,

R

2=0.037


2=0.042 Y=-1.196X-0.053, R

2=0.279

Langmuir Y =260.63X+56.067, R2=0.0503 Y=-162.9X+86.98, R

2=0.019 Y=-320.9X+76.77, R

2=0.326

Temkin Y = 2.7289X+2.9706, R2=0.1513 Y=2.238X+2.824, R

2=0.092 Y=-2.325X+2.549, R

2=0.328

D-R Y =-1 x10-5

X-3.2837, R2=0.1286 Y=-3×10

-5X-3.276, R

2=0.033 Y=2×10—5

X-4.287, R

2=0.354


2=0.101 Y=-0.729X-0.49, R

2=0.215

Langmuir Y = -129.76X+78.675, R2=0.0305 Y=-5.369X+39.05, R

2=0.000 Y=-63.81X+32.74, R

2=0.131

Temkin Y = 3.093X+2.7259, R2=0.111 Y=3.756X+2.433, R

2=0.185 Y=-2.34X+2.146, R

2=0.216

D-R Y = -0.001X-2.857, R2=0.0511 Y=2×10

-6X-2.760, R

2=0.085 Y=4×10

-6X-3.360, R

2=0.241

Table 3. Biomass reduction (%) with respect to fresh weight after 72 hours of exposure.

Conc.(ppm) M1 M2 M3 M4 M5 M6

10 95.05a 96.33

a 86.98

c 96.27

a 95.55

a 94.06

b

30 94.67b 97.82

a 95.57

a 84.99

d 85.59

c 96.39

a

50 96.46a 95.44

b 91.87

b 86.15

c 88.52

b 95.74

a

100 92.49c 95.20

b 95.89

a 88.73

b 83.78

d 95.82

a



The pigment concentration of all studied

macrophytes under different fluoride strength solution

is represented in Table 4. It is clear that different

macrophyte showed different level of pigment under

fluoride stress condition. However, lower level of

pigment was recorded at higher concentration.

Chlorophyll level decrease due to inhibition of enzyme

activity such as δ- aminolevulinic acid dehydrates

(Padmaja et al. 1990) and protochlorophylide reductase

(Van Assche and Clijsters 1990). Electrostatic

interaction of F- with Mg in chlorophyll structure causes

destruction of chloroplast membrane through lipid

peroxidation which again accelerated due to increase

in peroxidase activity and lack of antioxidants such as

carotenoid (Prasad and Strazlka 1999), reduction in

density, size and the synthesis of chlorophyll and

inhibition in the activity of some enzymes of Calvin

cycle (Baryla et al. 2001, Benavides et al. 2005).

Regarding the pigment content, fluoride treated plants

showed a remarkable decrease in chlorophyll that

causes photosynthesis rate enormously decrease in

response to elevated F- concentration. In another

word, chloroplast contains many different parts that

respond to F- stress, therefore any changes in

chlorophyll synthesis and activity used as the index of

direct toxic effects of F-. Also increase in chlorophyll

ratio (a/b) in higher treatment (Table 4) showed that

chlorophyll ‘b’ is more sensitive to F- that disrupt the

balance between energy trapping in photo system II

and cause a decrease in electron transport (Falkwosky

and Raven 2007).

The carotenoid content decreased in response to

all treatments except in low concentration (10 ppm) of

F-. That may indicate a severe effect of F

- on cells and

its component parts in compared to other nonmetals.

Hence, it can be suggested that at first carotenoid

content increased to protect the cells against these

nonmetals, but in high concentration (100 ppm) F-

activate some mechanism and degrade carotenoid

pigments. Carotenoid is a non-enzymatic antioxidant

pigment which protects chlorophyll, membrane and cell

genetic composition against ROS under F- stress (Hou

et al. 2007). In plant cell protection mechanism of this

pigment is probably due to quenching of triplet

chlorophyll, replacing peroxidation and destruction of

chloroplast membrane (Kenneth et al. 2000). Previous

findings also proved the decrease in carotenoid

concentration is a common response to metal or

nonmetal toxicity (Rout et al. 2001), but increase is due

to important role of this pigment in detoxifying ROS

(Tewari et al. 2002, Chandra et al. 2009). As fluoride is

a densely charged anion, when it reaches the leaves, it

can readily bind with Mg+

producing MgF+ complex.

Such kind of fluoride complex can destroy the

photosynthetic pigments, particularly the chlorophylls

(Ivinskis and Murray 1984, Trapp and McFarlane 1995,

Dey et al. 2012). Therefore, these are the probable

cause of significant decrease of chlorophyll

concentration under higher fluoride concentration

medium.

The correlation study of combined effects for

accumulation of fluoride revealed that at 10 ppm, Pistia

sp. (M1) was positively correlated with Ceratophyllum

sp. (M2) and Nymphoides sp. (M3) at 1% level of

significance during 24 h (Table 5). Again Lemna sp.

(M4) showed positive correlation with Azolla sp. (M5)

(p<0.05), and Eichhornia sp. (M6) (p<0.01). Moreover

Ceratophyllum sp. (M2) showed highly positive

correlation with Azolla sp. (p<0.01) during 24 h

(Table 5). During 48 h (10 ppm) a strong positive

correlation was found for Pistia sp. (M1) with

Ceratophyllum sp. (M2), Nymphoides sp. (M3),

Lemna sp. (M4), and Eichhornia sp. (M6) and between

the pairs Ceratophyllum sp. (M2) and Nymphoides sp.

(M3), Ceratophyllum sp. (M2) and Eichhornia sp. (M6),

Lemna major (M4) and Eichhornia (M6) at 1% level of

significance (Table 5). During 72 h (10 ppm) there was

good positive correlation (p<0.01) among Pistia sp.

(M1) and Ceratophyllum sp. (M2). Eichhornia sp. (M6)

also shows strong positive correlation (p<0.01) with

Pistia sp. (M1) and Ceratophyllum sp. (M2). More or

less all the macrophytes showed good performance

when concentrations are increased from 10 ppm to 30

ppm. The fluoride adsorption efficiencies of

macrophytes decrease from 24 h to 48 h and then

increase at 72 h. At higher concentrations, 50 ppm and

100 ppm, the adsorption phenomenon showed a little

difference from lower strength of the solution.

Interestingly, some negative results indicated that

macrophyte did not show adsorption performance

together or they showed some resorption

phenomenon.

Again from DW:FW ratios it had been found that

macrophytes M4 and M5 showed higher ratio at all

concentrations (30 ppm, 50 ppm, and 100 ppm),

excepting at 10 ppm F- solution. But reverse picture

was found for M3 macrophyte. The macrophytes M1,

M2, and M6 did not show higher DW:FW ratio in all

concentration (Figure 2). The relative growth rate

(RGR) of M2, M3, and M5 macrophytes showed a little

higher than other macrophytes at 30 ppm. But only M6

macrophyte showed the highest RGR at 10 ppm F-

solution (Figure 3). The RGR is significantly (p<0.05)

reduced at 50 ppm and 100 ppm F- solution for M1,

M4, and M5 possibly due to bioaccumulation of F- and

disturbance in plant’s water stress (Garnczarsk and

Ratajczak 2000, Perfus-Barbeoch et al. 2002). Despite

of growth inhibition, there is steady decline of total

chlorophyll, Chl’a’/Chl’b’ and carotenoid content in all

the tested macrophytes (Artetxe et al. 2002).



Table 4. Pigment concentration of macrophytes under different strength of fluoride solution.

Parameter F

(ppm)

Azolla sp. Lemna sp.

24 h 48 h 72 h 24 h 48 h 72 h

Chl ‘a’ (mg.g

-1.fw)

10 0.57 ± 0.02c

0.78 ± 0.01b

0.54 ± 0.11c

0.51 ± 0.01a

0.73 ± 0.04b

0.87 ± 0.05d

30 1.70 ± 0.01a

2.30 ± 0.06a

2.60 ± 0.78b

0.43 ± 0.01b

0.51 ± 0.06d

1.20 ± 0.03c

50 1.30 ± 0.39b

0.56 ± 0.11c

5.10 ± 0.01a

0.56 ± 0.06a

0.67 ± 0.01c

4.10 ± 0.25a

100 1.20 ± 0.33b

0.54 ± 0.21c

2.10 ± 0.02b

0.46 ± 0.05b

0.87 ± 0.02a

2.50 ± 0.047b

Chl ‘b’ (mg.g

-1.fw)

10 0.45 ± 0.01c

0.47 ± 0.03b

0.47 ± 0.13c

0.42 ± 0.02b

0.56 ± 0.03b

0.61 ± 0.01b

30 0.93 ± 0.05a

1.10 ± 0.02a

1.50 ± 0.06b

0.48 ± 0.04a

0.25 ± 0.04c

0.68 ± 0.023b

50 0.90 ± 0.08a

0.50 ± 0.05b

2.40 ± 0.09a

0.32 ± 0.01c

0.61 ± 0.01a

1.60 ± 0.05a

100 0.63 ± 0.01b

0.47 ± 0.22b

1.10 ± 0.01b

0.23 ± 0.09d

0.61 ± 0.01a

1.00 ± 0.11b

Total Chl (mg.g

-1.fw)

10 1.10 ± 0.22c

1.30 ± 0.34c

1.10 ± 0.01d

9.50 ± 0.01a

1.30 ± 0.01b

1.50 ± 0.025d

30 2.90 ± 0.34a

3.60 ± 0.47b

4.40 ± 0.01b 0.94 ± 0.01

b 0.79 ± 0.04

c 5.30 ± 0.33

b

50 2.30 ± 0.21b

1.10 ± 0.35d

8.10 ± 0.04a

0.94 ± 0.01b

1.30 ± 0.03b

6.10 ± 0.14a

100 2.00 ± 0.47b

3.90 ±0.33a

3.50 ± 0.01c

0.72 ± 0.01c

3.90 ± 0.024a

3.70 ± 0.22c

Chl ‘a’/Chl ‘b’

10 1.27 ± 0.59d

1.66 ± 0.36b

1.15 ± 0.06d

1.21 ± 0.11c

1.30 ± 0.02b

1.43 ± 0.014c

30 1.83 ± 0.14b

2.09 ± 0.65a

1.73 ± 0.07c

0.89 ± 0.04d

2.04 ± 0.06a

1.76 ± 0.11c

50 1.44 ± 0.69c

1.12 ± 0.44c

2.13 ± 0.01a

1.68 ± 0.02b 1.10 ± 0.04

c 2.56 ± 0.36

a

100 1.90 ± 0.28a

1.15 ± 0.28c

1.91 ± 0.01b

2.00 ± 0.03a

1.43 ± 0.22b

2.50 ± 0.03b

Total Chl/carotenoid

10 8.46 ± 0.37b

6.50 ± 0.57b

3.23 ± 0.04d

27.9 ± 40.06a

7.65 ± 0.11c

13.60 ± 30.01b

30 5.37 ±0.22d

5.37 ± 0.47c

7.33 ± 0.07a

12.37 ± 0.01b

5.64 ± 0.05d

24.09 ± 0.03a

50 10.45 ± 0.74a

16.17 ± 0.19a

5.06 ± 0.09b

7.83 ± 0.04c

8.42 ± 0.04b

2.90 ± 0.05d

100 6.25 ± 0.29c

6.39 ± 0.01b

4.43 ± 0.07c

5.54 ± 0.01d

11.18 ± 0.01a

4.11 ± 0.01c

Carotenoid (mg.g

-1.fw)

10 0.13 ± 0.19d

0.20 ± 0.44c

0.034 ± 0.01d

0.34 ± 0.01a

1.70 ± 0.01a

0.11 ± 0.01

30 0.54 ± 0.11a

0.67 ± 0.34a

0.60 ± 0.08c

0.08 ± 0.04c

0.14 ± 0.05b

0.22 ± 0.01

50 0.22 ± 0.01c

0.07 ± 0.55d

1.60 ± 0.01a

0.12 ± 0.01b

0.02 ± 0.04c

2.10 ± 0.03a

100 0.32 ± 0.25b

0.61 ± 0.65b

0.79 ± 0.01b

0.13 ± 0.04b

0.11 ± 0.07b

0.90 ± 0.05b

Parameter F

(ppm)

Ceratophyllum sp. Nimphoides sp.

24h 48h 72h 24h 48h 72h

Chl ‘a’ (mg.g

-1.fw)

10 1.30 ± 0.01a

0.43 ± 0.02c

0.71 ± 0.22b

0.53 ± 0.01b

0.57 ± 0.01b

0.78 ± 0.01b

30 1.60 ± 0.05a

0.29 ± 0.34d

1.50 ± 0.01a

0.35 ± 0.03c

1.70 ± 0.01a

2.30 ± 0.22a

50 0.65 ± 0.01b

1.4 ± 0.01a

0.61 ± 0.36b

0.62 ± 0.33a

1.30 ± 0.33a

0.56 ± 0.37b

100 0.68 ± 0.02b

0.71 ± 0.03b

1.90 ± 0.01a

0.67 ± 0.32a

1.20 ± 0.11a

0.54 ± 0.14b

Chl ‘b’ (mg.g

-1.fw)

10 0.60 ± 0.21b

0.32 ± 0.87c

0.54 ± 0.24b

0.20 ± 0.06c

0.45 ± 0.03b

0.47 ± 0.01b

30 1.20 ± 0.11a

0.14 ± 0.22d

0.68 ± 0.11a

0.35 ± 0.01a

0.93 ± 0.30a

1.10 ± 0.02a

50 0.39 ± 0.04c

0.77 ± 0.08a

0.31 ± 0.02c

0.22 ± 0.01b

0.90 ± 0.01a

0.50 ± 0.01b

100 0.35 ± 0.75c

0.54 ± 0.01b

0.57 ± 0.04b

0.29 ± 0.01b

0.63 ± 0.01b

0.47 ± 0.07b

Total Chl (mg.g

-1.fw)

10 2.10 ± 0.04b

0.78 ± 0.01c

1.30 ± 0.12b

0.77 ± 0.02b

1.10 ± 0.08c

1.30 ± 0.33b

30 3.10 ± 0.04a

0.48 ± 0.02d

2.50 ± 0.01a

1.30 ± 0.02a

2.90 ± 0.01a

3.60 ± 0.22a

50 1.10 ± 0.06c

2.30 ± 0.01a

0.99 ± 0.07b

0.56 ± 0.03b

2.30 ± 0.04b

1.10 ± 0.08b

100 1.10 ± 0.06c

1.00 ± 0.11b

2.05 ± 0.05a

1.20 ± 0.03a

2.00 ± 0.02b

3.90 ± 0.26a


10 2.16 ± 0.22a

1.34 ± 0.04b

1.31 ± 0.01d

1.15 ± 0.07c

1.27 ± 0.03d

1.66 ± 0.55b

30 1.33 ± 0.04d

2.07 ± 0.21a

2.20 ± 0.22b

2.43 ± 0.01a

1.83 ± 0.03b

2.09 ± 0.21a

50 1.66 ± 0.09c

1.18 ± 0.01c

1.97 ± 0.11c

1.45 ± 0.01b

1.44 ± 0.09c

1.12 ± 0.23b

100 1.94 ± 0.09b

1.31 ± 0.01b

3.33 ± 0.04a

3.03 ± 0.01a

1.90 ± 0.99a

1.15 ± 0.33b


10 5.00 ± 0.09b 3.40 ± 0.001

c 6.19 ± 0.23

a 18.33 ± 0.03

a 8.46 ± 0.09

b 6.50 ± 0.69

b

30 3.37 ± 0.03d

13.63 ± 0.11a

4.38 ± 0.22b

10.00 ± 0.01b

5.37 ± 0.06c

5.37 ± 0.09c

50 5.79 ± 0.01a

5.23 ± 0.02b

5.82 ± 0.36a

6.29 ± 0.01c

10.45 ± 0.05a

10.45 ± 0.01a

100 4.07 ± 0.01c

6.66 ± 0.03b

1.04 ± 0.01c

7.06 ± 0.06c

6.25 ± 0.03c

6.25 ± 0.01b



Carotenoid (mg.g

-1.fw)

10 0.42 ± 0.01b

0.23 ± 0.23b

0.21 ± 0.01c

0.04 ± 0.02b

0.13 ± 0.02b

0.13 ± 0.03d

30 0.92 ± 0.02a 0.11 ± 0.03

c 0.57 ± 0.01

b 0.13 ± 0.01

a 0.54 ± 0.01

a 0.54 ± 0.01

a

50 0.19 ± 0.07c

0.44 ± 0.01a

0.17 ± 0.40c

0.09 ± 0.01b

0.22 ± 0.01b

0.22 ± 0.01c

100 0.27 ± 0.03c

0.15 ± 0.07c

2.40 ± 0.01a

0.17 ± 0.01a

0.32 ± 0.01b

0.32 ± 0.03b

Parameter F

(ppm)

Eichhornia sp. Pistia sp.

24h 48h 72h 24h 48h 72h

Chl ‘a’ (mg.g

-1.fw)

10 0.89 ± 0.22c

0.46 ± 0.22b

0.77 ± 0.22b 0.53 ± 0.88

b 0.62 ± 0.22

b 3.10 ± 0.01

a

30 0.95 ± 0.33c

0.65 ± 0.32b

0.37 ± 0.33c

0.87 ± 0.46a 0.82 ± 0.30

b 3.80 ± 0.02

a

50 1.60 ± 0.01a 3.40 ± 0.01

a 0.28 ± 0.01

d 0.73 ± 0.35

a 3.10 ± 0.01

a 1.50 ± 0.22

b

100 1.30 ± 0.01b

0.77 ± 0.01b

2.40 ± 0.01a

0.78 ± 0.21a 3.10 ± 0.75

a 1.30 ± 0.04

b

Chl ‘b’ (mg.g

-1.fw)

10 0.41 ± 0.01b 0.25 ± 0.04

b 0.51 ± 0.01

b 0.25 ± 0.01

a 3.10 ± 0.06

a 1.40 ± 0.02

b

30 0.32 ± 0.01c

0.25 ± 0.25b

0.18 ± 0.01d 0.29 ± 0.01

a 3.60 ± 0.66

a 1.60 ± 0.01

a

50 0.58 ± 0.01a

1.50 ± 0.32a

0.26 ± 0.30c 0.29 ± 0.02

a 2.00 ± 0.02

a 0.79 ± 0.01

c

100 0.42 ± 0.06b

1.51 ± 0.02a

1.40 ± 0.44a

0.30 ± 0.07a 1.40 ± 0.01

b 0.64 ± 0.01

c

Total Chl (mg.g

-1.fw)

10 1.40 ± 0.01a

0.75 ± 0.01b

1.40 ± 0.02b 0.85 ± 0.08

b 0.97 ± 0.01

c 4.80 ± 0.02

b

30 1.40 ± 0.01a

0.94 ± 0.22b

0.74 ± 0.01c 1.20 ± 0.74

b 1.20 ± 0.01

c 5.60 ± 0.55

a

50 0.23 ± 0.01b

5.20 ± 0.04a

0.56 ± 0.01c 1.10 ± 0.09

b 5.60 ± 0.05

a 2.40 ± 0.05

c

100 1.80 ± 0.01a

5.60 ± 0.01a

4.10 ± 0.01a

1.30 ± 0.01a 4.90 ± 0.07

b 1.90 ± 0.01

c


10 2.17 ± 0.01c

1.84 ± 0.01b

1.51 ± 0.44b 2.12 ± 0.01

c 2.00 ± 0.04

b 2.21 ± 0.01

a

30 2.97 ± 0.05b

2.60 ± 0.01a

2.05 ± 0.01a 3.00 ± 0.21

a 2.28 ± 0.41

a 1.90 ± 0.01

b

50 2.76 ± 0.05b

2.27 ± 0.13b

1.07 ± 0.37c

2.52 ± 0.11b 1.55 ± 0.11

c 2.37 ± 0.01

a

100 3.09 ± 0.03a

1.5 ± 0.01b

1.71 ± 0.01b 2.60 ± 0.04

b 2.21 ± 0.01

a 2.03 ± 0.01

a


10 1.29 ± 0.01c

1.59 ± 0.01d

14.73 ± 0.01a

5.31 ± 0.11a 4.04 ± 0.02

a 4.36 ± 0.03

a

30 2.06 ± 0.04a 1.71 ± 0.01

c 1.67 ± 0.01

b 2.70 ± 0.22

c 4.14 ± 0.01

a 2.96 ± 0.11

b

50 1.92 ± 0.04b

7.65 ± 0.03b

1.54 ± 0.24b

3.67 ± 0.52b 4.00 ± 0.01

a 4.00 ± 0.02

b

100 1.64 ± 0.11c

16.47 ± 0.05a

10.78 ± 0.31b

4.06 ± 0.66a 4.45 ± 0.02

a 4.63 ± 0.03

a

Carotenoid (mg.g

-1.fw)

10 0.61 ± 0.01b

0.47 ± 0.11b

0.09 ± 0.02a

0.16 ± 0.76c

0.24 ± 0.01b

1.40 ± 0.03a

30 0.68 ± 0.02b

0.55 ± 0.14b

0.01 ± 0.02c

0.43 ± 0.01a 0.29 ± 0.03

b 1.10 ± 0.01

a

50 1.20 ± 0.01a

0.68 ± 0.07a

0.03 ± 0.44b

0.30 ± 0.20b

1.40 ± 0.01a 0.81 ± 0.22

b

100 1.10 ± 0.66a

0.034 ± 0.06c

0.04 ± 0.01b

0.32 ± 0.01b 1.10 ± 0.01

a 0.41 ± 0.14

b

Means within the column with same letter(s) did not differ significantly by Duncan’s Multiple Range Test (P = 0.05).

CONCLUSIONS

Hydrophytes offer a potential avenue for aquatic

phytoremediation. The six species tested in this study

showed large F- accumulation and significant biomass

accumulation, leading to large rates of F- removal from

solution. The results also show the significant effect of

plant. Present results also demonstrate that different

macrophyte showed different fluoride removal

efficiency. Most of the macrophytes show highest

fluoride removal during 24 h to 48 h, but after 72 h their

efficiency reduced drastically. The macrophyte

Nymphaca sp. (M3) shows best removal efficiency

rather than other macrophytes. Moreover correlation

study indicates that various combinations of

macrophytes has enough potential for removal of

fluoride from water. The percentage removal after 72 h

at 10 ppm was highest for macrophyte M6 (57.8%); at

30 ppm was highest with macrophyte M3

(98.83%); at 50 ppm was highest with M6 .Therefore

finally it may be concluded that these macrophyte are

better for removal of fluoride from higher

concentrations.

References

APHA (American Public Health Association). 1998. Standard

method for examination of water and wastewater, 20th edition,

Washington, DC, USA.

Arnon DI. 1949. Copper enzymes in isolated chloroplast polyphenol

oxidase in Beta vulgaris. Plant Physiol 24:1–15.

Artetxe U, García-Plazaola JI, Hernández A, Becerril JM. 2002.

Low light grown duckweed plants are more protected against the

toxicity induced by Zn and Cd. Plant Physiol Bioche 40: 859–863.

Baryla A, Carrier P, Franck F, Coulomb C, Sahut C, Havaux M.

2001. Leaf chlorosis in oilseed rape plants (Brassica napus)

grown on cadmium polluted soil: causes and consequences for

photosynthesis and growth. Planta 212: 696–709.

Benavides M., Gallego TML. 2005. Cadmium toxicity in plants.

Brazilian J Plant Physiol 17: 21–34.

Bogin E, Abrams M, Avidar Y, Israel B. 1976. Effect of fluoride on

enzymes from serum, liver, kidney, skeletal and heart muscles of

mice. Fluoride 9:42–46.



Brix H, Sorrell BK, Orr PT. 1993. Oxygen exchange by entire root

systems of Cyperus involucratus and Eleocharis sphacelata. J

Aquatic Plant Manage 31: 24–28.

Brooks RR, Robinson BH. 1998. Aquatic phytoremediation by

accumulator plants. In: Plants that hyperaccumulate heavy metals:

their role in archaeology, microbiology, mineral exploration,

phytomining and phytoremediation. In. Brooks RR (Ed.). CAB

International Wallingford. pp. 203–226.

Camargo JA. 2003. Fluoride toxicity to aquatic organisms: a review.

Chemosph 50: 251–264.

Table 5. Correlation among different macrophytes with respect to fluoride encapsulation.

Relation between Time Concentration of fluoride solutions (ppm)

10 30 50 100

M1 & M2

24 h

0.641** 0.939** 0.783**

M1 & M3 0.608** 0.995** 0.918**

M1 & M4 0.680** 0.594*

M1 & M5 0.934**

M1 & M6 0.954** 0.763**

M2 & M3 0.526* 0.824**

M2 & M4 0.859**

M2 & M5 0.875** 0.999** 0.592*

M2 & M6 0.981**

M3 & M4 0.790** 0.812**

M3 & M5 0.539*

M3 & M6 0.530*

M4 & M5 0.574* 0.878** 0.707**

M4 & M6 0.979** 0.749** 0.745**

M5 & M6 0.972**

M1 & M2

48 h

0.716** 0.493*

M1 & M3 0.683** 0.996**

M1 & M4 0.877** 0.760** 0.862** 0.874**

M1 & M5 0.690**

M1 & M6 0.971** 0.827**

M2 & M3 0.998** 0.953**

M2 & M4 0.802**

M2 & M5 0.887**

M2 & M6 0.739** 0.884**

M3 & M4 0.804**

M3 & M5 0.726** 0.731**

M3 & M6 0.719** 0.858** 0.773** 0.756**

M4 & M5 0.590** 0.451*

M4 & M6 0.920** 0.722**

M5 & M6 0.975** 0.980**

M1 & M2

72 h

0.928**

M1 & M3 0.660**

M1 & M4 0.538* 0.999** 0.969** 0.841**

M1 & M6 0.949** 0.982**

M2 & M3 0.470*

M2 & M4 0.673**

M2 & M5 0.893** 0.981**

M2 & M6 0.998** 0.994**

M3 & M5 0.646** 0.461* 0.808**

M3 & M6 0.524* 0.760**

M4 & M6 0.638** 0.989**

M5 & M6 0.957** 0.993**

OBS.: * and ** indicate significance by 5% and 1% of probability by F test.



Figure 2. Dry weight to fresh weight ratio of different

macrophytes under different concentrations of Fluoride

solution.

Figure 3. RGR of different macrophytes under different

concentration of fluoride solution

Cedergreen N, Abbaspoora M, Sorensen H, Streibig JC. 2007. Is

mixture toxicity measured on a biomarker indicative of what

happens on a population level? A study with Lemna minor. Ecotox

Environ Safe 67: 323–332.

Chandra R, Bhargava RN, Yadav S, Mohan D. 2009. Accumulation

and distribution of toxic metals in wheat (Triticum aestivum L.) and

Indian mustard (Brassica campestris L.) irrigated with distillery and

tannery effluents. J Hazard Mater 162: 1514–1521.

Delgado M, Guardiol AE, Bigeriego M. 1995. Organic and

inorganic nutrients removal from pigslurry by water hyacinth. J

Environ Sci Health A 30: 1423–1434.

Dey U, Mondal NK, Das K, Datta JK. 2012. Dual effect of fluoride

and calcium on the uptake of fluoride, growth physiology,

pigmentation and biochemistry of gram seedliing (Cicer arietinum

L.). Fluoride 45: 349–353.

Dunbabin JS, Bowmer KH. 1992. Potential use of constructed

wetlands for reatment of industrial wastewaters containing metals.

Scie Total Environ 111: 151–168.

Dushenkov S, Kapulnik Y. 2000. Phytofilitration of metals. In: Raskin

I, Ensley BD (Eds.). Phytoremediation of toxic metals - using

plants to cleanup environment. John Wiley and Sons, Inc, New

York. pp. 89–106.

Falbo MB, Weaks TE. 1990. A comparison of Eichhornia crassipes

(Pontederiaceae) and Sphagnum quinquefarium (Sphagnaceae) in

treatment of acid mine water. Econ Bot 4: 40-49.

Falkowski PG, Raven JA. 2007. Aquatic photosynthesis, Ed 2

Princeton University Press, Princeton, NJ.

Gomez KA, Gomez AA. 1984. Statistical procedures for agricultural

research. John Wiley and Sons Inc. London, UK (2nd

ed.). pp. 13–

175.

Hemens J, Warwick RJ. 1972. The effect of fluoride on estuarine

organisms. Water Res 6: 1301-1308.

Hoagland DR, Arnon, DI. 1950. The water culture method for

growing plants without soil. Calif Agr Exp Sta Circ 347: 32.

Hou W, Chen X, Song G, Wang Q, Chang CC. 2007. Effects of

copper and cadmium on heavy metal polluted waterbody

restoration by duckweed (Lemna minor). Plant Physiol Biochem

45: 62–69.

Hu S, Luo T, Jing C. 2012. Principal component analysis of fluoride

geochemistry of ground water in Shanxi and Inner Mongolia,

China. J Geochem Explor (In press).

Hunt ,R., 1978. Plant growth analysis studies in Biology. No. 96.

Edward Arnold Ltd., London, pp 67.

Huebert DB, Shay JM. 1992. Zinc toxicity and its interaction with

cadmium in the submerged aquatic macrophyte Lemna trisulca L.

Environ Toxicol Chem 11: 715–720.

Ivinskis MM. 1984. Associat ions between metabolic

injury and f luoride susceptibi l i ty in two species

of Eucalyptus. Environ Pollut (Ser A) 34: 207–223.

Jain SΜ, Newton RJ. 1989. Evaluation of protoclonal variation

versus chemically induced mutagenesis in Brassica napus L.

Current Sci 58: 176–180.

Rao KC, Indusekhar VK. 1989. Distribution of certain cations and

anions in sea weeds and seawater of Saurashtra coast and their

geochemical significance. Indian Journal of Marine Sciences 18:

37–42.

Kenneth E, Pallett KE, Young AJ, 2000. Carotenoids. In: Ruth GA,

Hess JL (Eds.). Antioxidents in higher plants. CRC Press USA.

Khataee AR, Movafeghi A, Vafaei F, Lisar SY, Zarei M. 2013.

Potential of the aquatic fern azolla filiculoides in biodegradation of

an azo dye: Modeling of experimental results by artifical neural

networks. International Journal of Phytoremedietion 15: 729–742.

McCune D., Weinstein LH, Jacobson JS, Hitchcock AE. 1964.

Some effects of atmospheric fluoride on plant metabolism. J Air

Pollut Control Asso 14: 465–468.

Msonda KWM, Masamba WRL, Fabiano E 2007. A study fluoride

groundwater occurrence in Nathenje. Phys Chem Earth 32:

1178–1184.

Panse VG, Sukhatme PV, 1967. Statistical Methods for Agricultural

Workers. 2nd edn. ICAR. New Delhi.

Padmaja K, Prasad DDK, Prasad ARK. 1990. Inhibition of

chlorophyll synthesis in Phaseolus vulgaris L. seedlings by

cadmium acetate. Photosynt 24: 399–405.

Perfus-Barbeoch l, Leonhardt N, Vavasseur A, Forestier C. 2002.

Heavy metal toxicity: Cadmium permeates through Calcium

channels and disturbs the plant water status. J Plant 32: 539–548.

Pitter P. 1985. Forms of occurrence of fluorine in drinking water.

Water Res 19: 281–284.

Prasad MNV, Strzalka K. 1999. Impact of heavy metals on

photosynthesis. In: Prasad MNV, Hagemayer J (Ed.). Heavy metal

stress in plants: from molecules to ecosystems. Spring, Berlin.

Qian X, Goderie SK, Shen Q, Stem JH, Temple S. 1998. Intrinsic

programs of patterned cell linages isolated vertebrate CNS

ventricular zone cells. Development 125: 3143–3152.

Rao NS, Devadas DJ. 2003. Fluoride incidence in groundwaters in a

part of Peninsular India. Environ Geol (In press).

Raskin I, Nanda Kumar PBA, Dushenkov V, Salt DE. 1994.

Bioconcentration of heavy metals by plants. Cur Opin Plant Biol

5: 285–290.

Rout GR, Samantaray S, Das P. 2001. Aluminum toxicity in plants:

a review. Agronomie 21: 3–21.

Steward KK. 1970. Nutritional removal potentials of various aquatic

plants. Hyacinth Countr J 9: 34–38.

Sultan DL, Ornes WH. 1975 Phosphorous removal from

static sewage effluent using duckweed. J Environ Quality 4: 367–

370.

Suthar H, Hingurao K, Desai A, Nerurkar A. 2008. Evaluation of

bioemulsifier mediated Microbial Enhanced Oil recovery using

sand pack column. J Microbiol Methods 75: 225–230.

Sutton DL, Omes WH. 1975. Phosphorus removal from

static sewage effluent using duckweed. 3. Environ Quality 4: 367–

370.



Tewari RK, Kumar P, Sharma PN, Bisht SS. 2002. Modulation of

oxidative stress responsive enzymes by excess cobalt. Plant Sci

162: 381–388.

Trapp S, McFarlane JC. 1995. Plant contaminat ion:

Modell ing and simulat ion of organic chemical

Processes. Boca Raton: Lewis; 25.

USEPA. Water Quality Criteria. 1975. Washington: Govt Printing

Office, Report No 73–133.

Van Assche F, Clijsters H. 1990. Effects of metals on enzyme

activity in plants. Plant Cell Environ 13: 195–206.

Weinstein LH, Alscher-Herman R. 1982. Physiological responses of

plants to fluorine. In: Unsworth MH, Ormrod DP, editors. Effects

of Gaseous Air Pollution in Agriculture and Horticulture. London:

Butterworths. pp. 139–176.

Wilson TRS. 1975. Salinity and the major elements of sea water. In:

Riley, J.P., Skirrow, G., editors. Chemical Oceanography Vol I.

New York: Academic Press. pp. 365–413.

Young GE, Langille WM. 1958. The occurrence of inorganic

elements in marine algae of the Atlantic provinces of Canada.

Can J Bot 36: 301–310.

Zurayk R, Sukkariah B, Baalbaki R. 2001. Common hydrophytes as

Bioindicators of nickel, chromium and cadmium pollution. Water Air

Soil Pollut 127: 373– 388.

Quality of English writing and reference information

are of totally responsibility of authors.

Date post:	30-Jan-2023
Category:	Documents
Upload:	buruni
View:	0 times
Download:	0 times

Fluoride remediation using floating macrophytes

Documents