International Journal of Scientific Research in Knowledge (IJSRK), 1(2), pp. 20-24, 2013 Available online at http://www.ijsrpub.com/ijsrk

©2013 IJSRPUB

20

Short Communication

The Potential of Lepidium sativum for Phytoremediation of Contaminated Soil with

Cadmium

Amir Hossein Vakili1*

, Mahnoosh Aboutorab2

1School of Civil Engineering, Engineering Campus, University Sains Malaysia, 14300 Nibong Tebal, Penang, Malaysia

2Department of Food Science, Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan, Iran

*Corresponding Author: Email: amirhoseinvakili@gmail.com

Received 29 December 2012; Accepted 19 January 2013

Abstract. The phytoremediation process was conducted under laboratory conditions with the use of garden cress plants

(Lepidium sativum). Soil samplings of 0-20 cm depth were taken. Lepidium sativum plantlets were planted in pots containing 3

kg of these soils. The experiment consisted of 4 treatments including soil without cadmium (T1), soil contaminated with 2

mg/kg concentration of cadmium (T2), soil contaminated with 4 mg/kg concentration of cadmium (T3), soil contaminated with

8 mg/kg concentration of cadmium (T4) were taken as experimental unit. Samples were taken for testing, after 35 days.

Physical and chemical characteristics of soil were measured before and after the test. These results showed that the Lepidium

sativum is an effective accumulator plant for phytoremediation of cadmium polluted soils. The results also showed that the

increasing contaminated to 8 (ppm) increased phytoremediation of cadmium from soil by Lepidium sativum. Accumulation of

Cd in roots was more than in shoots.

Key words: Cadmium, Lepidium sativum, Phytoremediation, Soil Contaminated,

1. INTRODUCTION

Environmental pollution with heavy metals is a global

disaster that is related to human activities such as

mining, smelting, electroplating, energy and fuel

production, power transmission, intensive agriculture,

sludge dumping and melting operations. All the heavy

metals high concentrations have strong toxic effects

and are regarded as environmental pollutants

(Chehregani et al., 2009).

Heavy metal pollution of soils has dramatically

increased in recent decades due to the discharge of

waste and wastewater from anthropogenic sources (Ji

et al., 2011). Large areas of land contaminated with

Cd were caused by anthropogenic activities such as

mining and mineral processing of metallic ores, waste

disposal, phosphate fertilizer application and

wastewater irrigation. Soil Cd contamination is a great

threat to human health since Cd is easily extracted by

plants from the environment compared with other

non-essential elements, and transferred to human food

chain from the soils (Xiao et al., 2008).

Restoration of contaminated soils with potentially

toxic metals and metalloids is of major global concern

(Shelmerdine et al., 2009). Compared with physical

and chemical techniques of remediation,

phytoremediation is a cost-effective and

environmental friendly green technology that utilizes

the capacity of hyperaccumulator plants to extract

heavy metals from soil (Ji et al., 2011).

Phytoremediation is the use of plants to clean up

environmental pollution. However, detoxification of

organic pollutants by plants is often slow, leading to

the accumulation of toxic compounds that could be

later released into the environment (Aken, 2008).

1.1. Phytoremediation process

(a) Uptake of organic compounds from soil and water;

(b) Accumulation or processing of these chemicals via

lignification, volatilization, metabolization,

mineralization; (c) Use of enzymes to break down

complex organic molecules into simpler molecules

(ultimately carbon dioxide & water) and (d) Increase

the carbon and oxygen content of soil around roots

(and so promote microbial/fungal activity) and decay

of root tissues (Kathi and Khan, 2011).

1.2. Phytoremediation techniques

There are 5 basic phytoremediation techniques: (1)

Rhizofiltration, a water remediation technique

involving the uptake of contaminants by roots of

plants. (2) Phytoextraction, a technique involving

uptake of contaminants from soil. (3)

Phytotransformation, applicable to both soil and water

and involves the degradation of contaminants through

plant metabolism. (4) Phyto-stimulation, (plant-

assisted bioremediation) used for both soil and water

and involves stimulation of microbial biodegradation

at the root zone. (5) Phytostabilization, using plants to

reduce the mobility and migration potential of

contaminants in soil (Kathi and Khan 2011).

Vakili and Aboutorab

The Potential of Lepidium sativum for Phytoremediation of Contaminated Soil with Cadmium

21

Xiao et al. (2008) investigated Potential of Pteris

vittata L. for phytoremediation of sites co

contaminated with cadmium and arsenic: The

tolerance and accumulation. The results suggested that

the Cd-tolerant ecotype of P. vittata extracted

effectively As and Cd from the site co-contaminated

with Cd and As, and might be used to remediate and

revegetate this type of site.

Chehregani et al. (2009) studied

phytoremediation of heavy-metal-polluted soils:

Screening for new accumulator plants in Angouran

mine (Iran) and evaluation of removal ability, the

study showed that the amounts of heavy metals in the

root, leave and shoot portions of N. mucronata varied

significantly but all the concentrations were more than

natural soils. The results indicated N.mucronata is an

effective accumulator plant for phytoremediation of

heavy-metals polluted soils.

In this study the phytoremediation of

contaminated soil with cadmium by Lepidium sativum

has been investigated.

2. MATERIALS AND METHODS

2.1. Site description, Sample preparation

The experiment was carried out at green house. Soil

samplings of 0-20 cm depth were taken. Lepidium

sativum plantlets were planted in pots containing 3 kg

of these soils. The experiment consisted of 4

treatments including soil without cadmium (T1), soil

contaminated with 2 mg/kg concentration of cadmium

(T2), soil contaminated with 4 mg/kg concentration

of cadmium (T3), soil contaminated with 8 mg/kg

concentration of cadmium (T4) were taken as

experimental unit. Samples were taken for testing,

after 35 days. The plant tissues were prepared by Wet

Digestion method (Campbell and Plank 1998). Soil

samples were allowed to air dry in a green house at a

temperature between 25ºC and 30ºC and were then

ground to pass a 2-mm mesh sieve for prepared of soil

samples (Mojiri et al. 2011).

2.2. Laboratory determinations

Physical and chemical characteristics of soil such as

soil texture, cation exchange capacity (CEC), soil

reaction (pH), electrical conductivity (EC), organic

matter (OM), extractable Fe and cadmium were

measured before and after the test.

Soil texture was determined by the Bouyoucos

hydrometer method (Gee and Bauder 1986). Soil pH

and EC were measured on 1:1 extract (Soil:Water).

Extractable cadmium in soil and plant samples were

carried out by DTPA in accordance the Standard

Methods (APHA, 1998). Soil OM was determined as

in Walkley and Black and CEC was determined (ASA

1982).

2.3. Statistical analysis

Descriptive statistical analysis, including mean

comparison using Duncan’s Multiple Range Test

(DMRT), was conducted using SPSS software.

4. RESULTS AND DISCUSSION

Soil properties before experiment, comparing the

means of treatments in soil and comparing the means

of treatments in Lepidium sativum are shown in

Tables 1, 2 and 3, respectively.

Table 1: Soil properties before and after experiment

pH EC

(dSm-1)

CEC

(me/100g)

OM

(%)

Clay

(%)

Sand

(%)

Silt

(%)

Fe

(ppm)

Cd

(ppm)

Main Soil (T1)

6.89 1.07 9.0 0.78 9.50 59.95 30.55 2.90 0

Table 2: Comparing the means of treatments in soil

Parameter Treatments

T1 T2 T3 T4

Cd (ppm) 0.00a+ 0.762b 1.971c 3.712d

+ Row means followed by the same letter are not significantly different at 0.05 probability level

International Journal of Scientific Research in Knowledge (IJSRK), 1(2), pp. 20-24, 2013

22

Fig. 1: Changes of Cadmium in soil

T1, T2, T3 and T4 are treatments 1, 2, 3 and 4, respectively

A and B are soils before 35 days and after 35 days, respectively

Cadmium has strong toxicity to plants, and the

normal range of Cd concentration in leaf tissues (dry

weight) of some plant species is approximate 0.05–0.2

mg/kg, and the excessive or toxic concentrations are

5–10 up to 30 mg/kg (Xiao et al., 2008). As known,

the exchangeable form Cd is easily absorbed by plant.

In the presence of vegetation, the exchangeable form

Cd was partly removed by plant uptake that

accompanied with the intake of nutrition (Zhang et al.,

2009).

Jai et al. (2011) reported the laboratory studies

indicate the amount of metal removed by plants is

related to the total amount present in soil, so when we

compare the Cd phytoextraction efficiency of several

hyperaccumulators, the relative values of the soil Cd

concentration must be taken into account to accurately

assess Cd phytoextraction efficiency.

The higher the Cd concentration in soil, the more

Cd is extracted by plants despite the fact that the

phytoextraction efficiency of hyperaccumulators

declines with increased metal concentration.

Table 3: Comparing the means of treatments in Lepidium sativum

Cd (ppm) Corn

Root Shoot

0 (T1) 0a+

0f

2 (T2) 4.791b 1.120g

4 (T3) 7.990c 2.294h

8 (T4) 13.312d 3.012i

+ Row means followed by the same letter are not significantly different at 0.05 probability level

Fig. 2: Changes of Cadmium in Lepidium sativum

T1, T2, T3 and T4 are treatments 1, 2, 3 and 4, respectively

R and S are Root and Shoot, respectively

According to Table 1 and 3, It was clear that the

concentration of Cd significantly decreased in the

planted soil after 35 days culture. Accumulation of

cadmium in roots is higher than in shoots. This result

showed that the root of Lepidium sativum is more

active than shoot to phytoremediation of cadmium.

This is in line with finding of Mojiri (2011), Zhang et

al. (2009) and Xiao et al. (2008).

Vakili and Aboutorab

The Potential of Lepidium sativum for Phytoremediation of Contaminated Soil with Cadmium

23

According to Table 1, increasing soil

contaminated to 8 (ppm) increased phytoremediation

of cadmium from soil by Lepidium sativum.

4. CONCLUSION

Environmental pollution with heavy metals is a global

disaster that is related to human activities. Large areas

of land contaminated with Cd were caused by

anthropogenic activities such as mining and mineral

processing of metallic ores, phosphate fertilizer

application and wastewater irrigation.

Phytoremediation is the use of plants to clean up

environmental pollution. The evidences provided by

this experiment indicated that the Lepidium sativum is

an effective accumulator plant for phytoremediation

of cadmium polluted soils.

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ASA (1982). Methods of Soil Analysis. Part 2.

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International Journal of Scientific Research in Knowledge (IJSRK), 1(2), pp. 20-24, 2013

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Amir Hossein Vakili is a PhD candidate at School of Civil Engineering, Universiti Sains Malaysia, 14300

Nibong Tebal, Penang, Malaysia.

Mahnoosh Aboutorab is a MSc student in food science, Isfahan (Khorasgan) Branch, Islamic Azad

University.