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Dr. Mohammad Shariful Islam

Professor, Department of Civil Engineering

Bangladesh University of Engineering and Technology (BUET)

Dhaka-1000, Bangladesh

Email: msharifulbd@gmail.com

Phytoremediation of Contaminated Land

Using Vetiver (Chrysopogon zizanioides L.) in Bangladesh Perspective

The Seventh International Conference on Vetiver (ICV-7)

29 May-01 June, 2023, Chiang Mai, Thailand

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Outline of the Presentation

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Background and Problem Statement

Ways of Solving the Problem

Research and Development

Research Gaps and Future Direction

Way Forward

Summary

❶

❷

❸

❹

❺

❻

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Background and �Problem Statement

01

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Extent of Soil Pollution in Bangladesh

Soil health in Bangladesh is deteriorating due to human activities and environmental factors, such as the excessive and unregulated use of chemical fertilizers, rising salinity, deforestation, industrial pollution, the use of topsoil in brick kilns, and the improper disposal of diverse wastes, including household, industrial, electronic, and medical, contributing to the presence of harmful heavy metals in the soil.

​

Following soil pollution problems are severe:

  1. Heavy Metal: Heavy metals like As, Cd, Cr, Hg, Pb, Cu, Zn, Ni are common pollutants in the soil environment that are biologically toxic.
  2. Salinity: Salinity in soil can reduce plant growth and water quality resulting in lower crop yields and water availability.

Sarkar et. al., (2017)

National Screening Program (2002-2003)

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Area

Name of Country(ies)

Type of Pollutant

South Asia

Bangladesh, India, Pakistan, Nepal, Sri Lanka

Arsenic, cadmium, chromium (VI), copper, lead, mercury, nickel and zinc

East Asia

Mainland China, Taiwan Province of China

Trace element, e.g., arsenic, cadmium, chromium, copper, lead, mercury, nickel, zinc and DDT, PAHs and HCHs (hexachlorocyclohexanes)

Republic of Korea

Oil, trace elements, e.g., arsenic, cadmium, chromium (VI), copper, mercury and lead, PCDD/Fs, fluorine

Japan

Radionuclide pollutant

Southeast Asia

Brunei Darussalam, Cambodia, Indonesia, Malaysia, Myanmar, The Philippines, Singapore, Thailand and Viet Nam

Arsenic, cyanide, lead, oil, TCE, PCE, iron

Soil Contamination State in Asia

FAO and UNEP. 2021. Global assessment of soil pollution: Report. Rome. doi.org/10.4060/cb4894en

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Direct Contribution

Indirect Contribution

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Soil pollution reduces income for rural people

Soil pollution affects food security

Soil pollution affects the global mortality

Women working in vulnerable jobs are more exposed to soil pollution

Soil pollution causes water pollution

Fossil fuels are a major source of contaminants

Poorly managed stockpiles can cause pollution

Soil pollution disproportionately affects people

Transport and waste production causes soil pollution

Industrial activities and mining are sources of soil pollution

Soil pollution contributes climate change

Marine pollution is caused by erosion of polluted soils

Contaminants in soil are pass into the food chain

Ethnic minority groups are affected by soil pollution

Developed countries need to actively collaborate on this issue

How Soil Pollution Hinders SDGs?

FAO and UNEP. 2021.Global Assessment of Soil Pollution: Report. Rome

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Permissible Limits of Heavy Metals in Soil and Plants

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Sl No

Elements

αTarget Values of Soil

(mg/kg)

βIntervention Values of

Soil

(mg/kg)

γPermissible Value of

Plants

(mg/kg)

1

Cd (Cadmium)

0.8

12

0.02

2

Cr (Chromium)

100

360

1.3

3

Cu (Copper)

36

190

10

4

Pb (Lead)

85

530

2

5

Ni (Nickel)

35

210

10

αTarget values are specified to indicate desirable maximum levels of elements in unpolluted soils (Denneman & Robberse, 1990)

βIntervention when remedial action is necessary; Source: Denneman and Robberse, 1990 and Ministry of Housing, Netherland, 1994

γWorld Health Organization, WHO (1996)

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Permissible Limits of Heavy Metals in Soil and Plants

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Elements

βIntervention

Values of

Soil

Triggered

levels for

human

health

ψNot

Polluted

ψHeavily

Polluted

ξTRV in

Soil for

Terrestrial

Plant

ξTRV in Soil

for Soil

Invertebrate

γPermissible

Value of

Plants

λRegulatory

limit

​

(mg/kg)

(mg/kg)

(mg/kg)

(mg/kg)

(mg/kg)

(mg/kg)

(mg/kg)

(mg/kg)

Cr (Chromium)

360

200

<25

>75

1.8δ

2δ

1.3

100

Cu (Coper)

190

500

<25

>50 

10

32

10

600

Pb (Lead)

530

500

<40

>60

46

100

2.00

600

Zn (Zinc)

-

2000

<90

>200

9

199

0.60

1500

Cd (Cadmium)

12

40

-

>6

2

10

0.02

100

βIntervention when remedial action is necessary; Source: Denneman and Robberse, 1990 and Ministry of Housing, Netherland, 1994

ψEPA guidelines for sediments (Ogbeibu et al., 2014)

ξScreening Level Ecological Risk Assessment Protocol, Appendix E: Toxicity Reference Values, U.S. EPA, August 1999. Weblink:

http://www.epa.gov/osw/hazard/tsd/td/combust/eco-risk/volume3/appx-e.pdf

δConcentration value corresponds to hexavalent chromium only

λNJDEP, 1996

γWHO, 1996

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Land Degradation and Erosion

Land degradation could threaten 700 million people globally

https://www.climateaction.org/news/land-degradation

https://youmatter.world/

Climate, soil, vegetation cover, topography, human and animal activity influence the Erosion. It has both environmental and economic impacts.

  • Erosion
  • Contamination
  • Salinization
  • Deforestation
  • Urbanization

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Ways of Solving �the Problem

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Based on the location of treatment, there are two categories of soil remediation techniques, ex-situ and in-situ.

  1. Ex-situ: Ex-situ technique involves treatment of contaminated soil after removing it from the site.
  2. In-situ: In contrast, in-situ methods aim to remediate the soil without need for excavation.

​

Some common methods of soil remediation include:

  • Microbial Bioremediation: Uses microorganisms, plants, or their enzymes
  • Cleanup of Contaminated Soil: Excavates and transports contaminated soil to secure landfills
  • Immobilization of Inorganic Contaminants: Uses efficient amendments for contaminant immobilization
  • Soil Washing: Separates contaminated fines but doesn't destroy contaminants
  • Phytoremediation: Uses green plants, especially metallophytes, to remove heavy metals from contaminated soils through natural or chelate-assisted modes that use agents like EDTA to increase bioavailability

​

The physico-chemical and phytoremediation techniques can remediate heavy metal contamination but physico-chemical methods are costlier and create environmental issues.

Methods of Remediation

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Phytoremediation

Rigoletto et al., (2020)

Phytoremediation

Phytoextraction

Plants remove heavy metals from soil and accumulate them in their foliage

Phytodegradation

Plants degrade organic pollutants

Rhizofiltration

Plant root system absorbs metals from waste system

Phytostabilization

Plants minimize movement of contaminants in soil environment

Phytovolatilization

Plants volatilize pollutants into the atmosphere

through

biological

activity

Types of Phytoremediation

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Phytoremediation

Recommendations

  • Advancement in spectroscopic and chromatographic techniques should be exploited to improve understanding of the fate of metal ions in plant tissues, which in turn will improve understanding of metal hyperaccumulation and tolerance in plants.
  • Existing plant diversity should be explored for hyperaccumulation of various heavy metals to find new effective metal hyperaccumulators.

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Limitations of Phytoremediation

  • Long time is required for clean-up.
  • Efficiency is usually limited by the slow growth rate and low biomass.
  • Difficulty in the mobilization of more tightly bound fractions of metal ions from soil.
  • It is applicable to sites with low to moderate levels of metal contamination because plant growth is not sustained in heavily polluted soils.
  • There is a risk of food chain contamination in case of mismanagement and lack of proper care.

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Phytoremediation Process

Translocation and Bioaccumulation (Yeh et al., 2015)

Experimental Pot

M = Heavy metal (Cu and Zn)

Chelator = EDDS, EDTA, DTPA, CA

Csoil = Metal concentration of soil

Croot = Metal concentration of root in plant

Cshoot = Metal concentration of shoot in plant

Chelator addition

Remediated Soil

M2+

M2+/chelator complexes

M2+

M2+/chelator complexes

Translocation

From root into shoot

TF = Cshoot/Croot

Translocation into

aboveground part

of plant

R

O-

COO-

Functional groups of soil surface

with organic matter

Increase metal mobility in pore water of

soil via chelator addition

Metal uptake by rhizesprere

BCF = Croot/Csoil

Plant (biomass) harvesting

Plant Uptake

Fixation

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Plant Species for Phytoremediation

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Plant Name

Plant Species

Chelating Agents

(dose in mM)

Root Concertation (mg/kg)

Shoot Concentration

(mg/kg)

References

Indian Mustard

Brassica juncea L.

EDTA (2.5)

500.00

 -

Blaylock et al., 1997

White Clover

Trifolium repens

EDTA (5.0)

3.27

 -

Kos et al., 2003

Empress Tree

Paulownia tomentosa

EDTA (10.0)

0.57

 -

Doumett et al., 2008

Empress Tree

Paulownia tomentosa

TAR (10.0)

0.47

 -

Doumett et al., 2008

Empress Tree

Paulownia tomentosa

GLU (10.0)

0.53

 -

Doumett et al., 2008

Cadmium (Cd)

Chromium (Cr)

Plant Name

Plant Species

Chelating Agents

(dose in mM)

Root Concertation (mg/kg)

Shoot Concentration

(mg/kg)

References

Vetiver

Vetiveria zizanioides

EDTA (5.0)

19.70

1.6

Choudhury et al., 2016

Indian Mustard

Brassica juncea L.

-

61.55

30.0

Choudhury et al., 2016

French Marigold

Tagetes patula

-

13.00

21.9

Choudhury et al., 2016

Napier Grass

Pennisetum purpureum

-

452.10

1241.6

Juel et al., 2021

EDTA=Ethylene Diamine Tetra Acetic Acid, TAR= Tartrate, GLU= Glutamate

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Plant Species for Phytoremediation

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Plant Name

Plant species

Chelating Agents

(dose in mM)

Root Concertation

(mg/kg)

Shoot Concentration

(mg/kg)

References

Vetiver

Vetiveria zizanioides

EDTA (5.0)

13.90

29.00

Choudhury et al., 2016

Indian Mustard

Brassica juncea L.

-

9.75

41.85

Choudhury et al., 2016

French Marigold

Tagetes patula

-

21.90

13.00

Choudhury et al., 2016

Common Bean

Phaseolus vulgaris

EDTA (5.0)

625.00

-

Luo et al., 2005

Corn Plant

Zea mais

EDTA (5.0)

428.00

-

Luo et al., 2005

Empress Tree

Paulownia tomentosa

EDTA (10.0)

45.50

-

Doumett et al., 2008

Empress Tree

Paulownia tomentosa

TAR (10.0)

36.80

-

Doumett et al., 2008

Empress Tree

Paulownia tomentosa

GLU (10.0)

46.60

-

Doumett et al., 2008

Sunflower

Helianthus annuus

EDTA (5.0)

480.00

105.00

Yeh et al., 2015

Chinese cabbage

Brassica campestris

EDTA (5.0)

420.00

150.00

Yeh et al., 2015

Cattail

Typha latifolia

EDTA (5.0)

330.00

115.00

Yeh et al., 2015

Reed

Phragmites communis

EDTA (5.0)

275.00

135.00

Yeh et al., 2015

Copper (Cu)

EDTA=Ethylene Diamine Tetra Acetic Acid, TAR= Tartrate, GLU= Glutamate

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Plant Species for Phytoremediation

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Plant Name

Plant species

Chelating Agents

(dose in mM)

Root Concertation

(mg/kg)

Shoot Concentration

(mg/kg)

References

Vetiver

Vetiveria zizanioides

EDTA (5.0)

19.40

33.90

Choudhury et al., 2016

Indian Mustard

Brassica juncea L.

-

6.00

16.50

Choudhury et al., 2016

French Marigold

Tagetes patula

-

37.65

36.25

Choudhury et al., 2016

Indian Mustard

Brassica juncea

EDTA (2.5)

3580.00

-

Blaylock et al., 1997

Rapeseed Plant

Brassica napus

EDTA (5.0)

93.92

-

Kos et al., 2003

Empress Tree

Paulownia tomentosa

EDTA (10.0)

31.00

-

Doumett et al., 2008

Empress Tree

Paulownia tomentosa

TAR (10.0)

12.40

-

Doumett et al., 2008

Empress Tree

Paulownia tomentosa

GLU (10.0)

16.20

-

Doumett et al., 2008

Lead (Pd)

EDTA=Ethylene Diamine Tetra Acetic Acid, TAR= Tartrate, GLU= Glutamate

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Plant Species for Phytoremediation

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Plant Name

Plant Species

Chelating Agents

(dose in mM)

Root Concertation

(mg/kg)

Shoot Concentration

(mg/kg)

References

Vetiver Plant

Vetiveria zizanioides

EDTA (5.0)

1130.00

995.00

Choudhury et al., 2016

Indian Mustard

Brassica juncea L.

-

584.50

562.00

Choudhury et al., 2016

French Marigold

Tagetes patula

-

265.15

159.05

Choudhury et al., 2016

Indian Mustard

Brassica juncea

EDTA (2.5)

1080.00

 -

Blaylock et al., 1997

White Clover

Trifolium repens

EDTA (5.0)

168.00

 -

Kos et al., 2003

Empress Tree

Paulownia tomentosa

EDTA (10.0)

149.00

 -

Doumett et al., 2008

Empress Tree

Paulownia tomentosa

TAR (10.0)

104.00

 -

Doumett et al., 2008

Empress Tree

Paulownia tomentosa

GLU (10.0)

114.00

 -

Doumett et al., 2008

Sunflower

Helianthus annuus

EDTA (5.0)

6700.00

3380.00

Yeh et al., 2015

Chinese Cabbage

Brassica campestris

EDTA (5.0)

5200.00

2650.00

Yeh et al., 2015

Cattail

Typha latifolia

EDTA (5.0)

3450.00

1900.00

Yeh et al., 2015

Reed

Phragmites communis

EDTA (5.0)

2600.00

1780.00

Yeh et al., 2015

Zinc (Zn)

EDTA=Ethylene Diamine Tetra Acetic Acid, TAR= Tartrate, GLU= Glutamate

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Vetiver Grass

(www.pinterest.com)

Factors

Tolerance Limit

pH

3.0 to 10.5

Salinity

10 to 47.5 dS/m

Sodicity

up to 48% ESP

Temperature

−15°C to 55°C

Drought

up to 6 months

Submergence

3 to 4 months

Heavy Metal

(in mg/kg)

-

Arsenic

100–250

-

Cadmium

20–60

-

Copper

50–100

-

Chromium

200–600

-

Lead

>1 500

-

Mercury

>6

-

Nickel

100

-

Selenium

>74

-

Zinc

>750

Rainfall/Precipitation

250-5000 mm

Characteristics

Value

Tensile Strength of Root

75 MPa

Carbon Sequestration Capacity

15-150 ton C/ha/year

www.vetiver.org (Ziyuan Feng)

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Carbon Sequestration of Vetiver and Other Grasses

Sl. No.

Type of Grass

Sequestered Carbon

Reference

1

Vetiver (Chrysopogon zizanioides)

15.24 ton C/ha/year

Singh et al. (2014),

Lakshmi and Sekhar (2020)

2

Lemongrass (Cymbopogon citratus)

5.38 ton C/ha/year

3

Palmarosa (Cymbopogon martini)

6.14 ton C/ha/year

4

Hybrid Napier

49.42 ton C/ha

Toppo et al. (2021)

5

Sudan Grass (Sorghum × drummondii)

42.36 ton C/ha

6

Zoysiagrass (Zoysia japonica)

5.54± 0.21 ton C/ha/year

Hamido et al. (2016)

7

Bermuda Grass (Cynodon dactylon)

2.09± 0.1 ton C/ha/year

8

Centipedegrass (Eremochloa ophiuroides)

4.23± 0.14 ton C/ha/year

9

Turfgrasses

0.32-0.78 ton C/ha/year

Qian et al. (2010)

10

Deep rooted tropical grasses in South America

100-500 ton C/ha/year

Grimshaw (n.d.)

11

Vetiver (Chrysopogon zizanioides)

150 ton C/ha/year

12

Vetiver (Chrysopogon zizanioides)

0.2 kg C/plant/year

As a whole, it can be said that vetiver can sequester higher carbon than other common grasses. However, the reporting and the data varies significantly in the existing literature which emphasize the need for further research on this topic considering soil characteristics, geographical locations.

Carbon Sequestration: is the process of preventing CO2 from entering the Earth’s atmosphere;

Carbon Sink: the reservoirs that retain the CO2.

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Commercial Uses of Vetiver

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Vetiver Availability in Bangladesh

Thomas et al., 2002

Haor village protection

Native Habitats of Vetiver in Bangladesh

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Reference

Contaminant

Additives

Suitability

Phytoextraction

Phytostabilization

Wilde et al., 2005

Pb

EDTA

​

✔

Minh and Khoa, 2009

Pb

-

✔

​

Minh and Khoa, 2009

Cd

-

​

✔

Datta et al., 2010

As

-

✔

​

Roongtanakiat and Sanoh, 2011

Zn

-

✔

​

Abaga et al., 2014

Cd

-

✔

​

Saeb et al., 2015

CN

-

✔

​

Vargas et al., 2016

Zn

Humic acid

​

✔

Vargas et al., 2016

Cu

Humic acid

✔

​

Attinti et al., 2017

Pb

EDDS

✔

​

Ng et al., 2019

Cd,Pb,Cu,Zn

EDTA

✔

​

Mu et al., 2019

Pb, Cr, Cu, and Zn

CaO-activated silicon-based slag

​

✔

Mu et al., 2019

Cd

CaO-activated silicon-based slag

✔

​

Chintani et al., 2021

Cr

-

​

​

Chintani et al., 2021

Ni

-

✔

​

Kriti et al., 2021

Ni, Cd

-

​

✔

Bahraminia et al., 2015

Pb

Mycorrhizal Fungi

​

✔

Huong et al., 2022

Dioxin

-

​

✔

Phytoremediation Mechanism of Vetiver

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Heavy Metals

Threshold Levels in Soil

(mg/kg)

Threshold Levels in Plants

(mg/kg)

Arsenic

100-250

21-72

Cadmium

20-60

45-48

Copper

50-100

13-15

Chromium

200-600

5-18

Lead

>1500

>78

Mercury

>6

>0.12

Nickel

100

347

Selenium

>74

>11

Zinc

>750

880

Threshold Level of Heavy Metals for Vetiver

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Research and �Development

03

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Phytoremediation Studies in Bangladesh

Reference

Location

Soil Type

Targeted Contaminants

Vegetation for Phytoremediation

Findings

Rahman et al., 2007

Manikganj

Paddy field

As

S. polyrhiza L.

Arsenate-exposed S. polyrhiza accumulated 79% more arsenic than DMAA-exposed

Mahmud et al., 2008

Khulna, Satkhira, Bagerhat, Brahmanbaria

-

​

As

Dryopteris filix-mas, Blumea lacera, Mikania cordata, Ageratum conyzoides, Clerodendrum trichotomum, Ricinus communis

As-tolerant accumulators, suitable for phytoextraction purpose

Islam et al., 2010

Chapai Nabwabganj

-

As

Pteris vittata L.

Tailoring solutions to local environments is key

Ye et al., 2011

Nonaghata, Faridpur and Sonargaon

Paddy field

As

Pteris vittata

The arsenic content in rice grains was reduced by 50-58%

Mayda et al., 2013

Savar

-

As

Adiantum sp, Microlepia sp, Pteris vittata, Christella sp

Pteris vittata excels in uptaking soil arsenic, tolerating 4000ppm concentration

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Phytoremediation Studies in Bangladesh

Reference

Location

Soil Type

Targeted Contaminants

Vegetation for Phytoremediation

Findings

Choudhury et al., 2016

Buriganga

Riverbed Sediment

Cu, Cr, Pb, Zn

Indian Mustard (Brassica juncea) and French Marigold (Tagetes patula)

Marigold excels in uptake of Cr, Pb, and Cu, while Indian mustard is efficient in Zn uptake 

Islam et al., 2016

Munshiganj

Agriculture Land topsoil

As

Vetiver Grass (Vetiveria zizanioides)

Vetiver grass can lower soil arsenic by up to 23%.

Nizam Uddin, 2016

Bhaluka Upazila

Industrially

polluted soil

Pb

Corchorus capsularis L., Hibiscus cannabinus, (Hibiscus sabdariffa L.)

Jute CVE-3 showed the highest Pb concentration (108.12 mg/kg), while kenaf HC-95 had the lowest (80.28 mg/kg) in post-harvest soil.

Islam et al., 2018

Kallyanpur

Reclaimed land soil

NH3, NO3, NO2, PO4, COD, pH

Vetiver Grass (Vetiveria zizanioides)

Soil organic matter increased from 4.3% to 6.4%, with 96% and 95% removal of ammonia and phosphate from wastewater

Rahman et al., 2019

Sitakunda Coast

Sediment

Fe, Ti, Zr, Rb, Zn, Sr, Pb, Y, Cu, Cr, As

A. alba and A. ilicifolius

Bioconcentration factors were <1, but transfer factors were >1 for most heavy metals in both plant species

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Phytoremediation Studies in Bangladesh

Reference

Location

Soil Type

Targeted Contaminants

Vegetation for Phytoremediation

Findings

Hasan et al., 2021

Savar

Soil around tanning Industries

Cr

Eichhornia crassipes, Xanthium strumarium L., Cynodon dactylon, Croton bonplandianum Baill

Xanthium strumarium L. showed high TF and BCF values for Cr

Riza & Hoque, 2021

Kaliakair

Soil around textile industries

Cu and Zn

Bryophyllum pinnatum

Bryophyllum pinnatum is a promising hyperaccumulator plant with BCF>1 and TF>1 values, suitable for phytoextraction

Juel et al., 2021

Gazipur

Soil containing tannery sludge

Cr, Cu, Zn, Pb

Napier Grass, Indian Mustard

Fast-growing Napier grass, can accumulate more heavy metals than Indian mustard over its lifespan

Present Study

Buriganga

Riverbank Soil

Cu, Cr, Pb, Ni, Zn

Vetiver Grass (Vetiveria zizanioides)

EDTA absorption efficiency did not improve above 1-2 mmol/kg of soil, and greater values induced leaf discoloration

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Vetiver-based Phytoremediation Studies around the World

Reference

Location

Soil

Sampling Depth

(cm)

Harvesting Period

(Days)

Amend-ments

Results

Before

After

Vetiver Uptake

Removal Efficiency

BCF

TF

Srisatit et al., 2003

Bangkok, Thailand

Silt Loam

×

90

×

50-150 mg/kg

×

×

0.04-0.05%

×

×

​

Datta et al., 2010

Texas, Florida,

USA

×

×

120

×

45-450 mg/kg

×

×

0.60-10.6%

×

×

​

Hosamane, 2012

Karnataka, India

×

×

60

×

10-50 mg/kg

×

​

63-85%

×

×

​

Oshunsanya et al., 2012

Nigeria

Dumpsite

0-100

90

×

10.5 mg/kg

×

0.03

mg/kg

×

×

×

​

Caporale et al., 2014

Rutgers, USA

Sandy Loam

Pot Depth 30

120

Arbuscular Mycorrhizal Fungi

12.5-50 mg/kg

×

×

×

×

<1

Islam et al., 2016

Munshiganj,

Bangladesh

Sand

×

180

×

18.8 mg/kg

15.2-16.6 mg/kg

×

×

×

×

​

Singh et al., 2017

Mumbai,

India

×

×

14

×

10-200 μM

×

×

×

×

<1

​

Arsenic, As

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Reference

Location

Soil

Sampling Depth

(cm)

Harvesting Period

(Days)

Amend-ments

Results

Before

After

Vetiver Uptake

Removal Efficiency

BCF

TF

Roongtanakiat & Chairoj, 2001

Thailand

Sandy Soil

×

120

15-15-15

Fertilizer

1.02-4.08 mg/kg

×

×

×

×

<1

Zhuang et al., 2007

Lechang, China

Pb/Zn Mine Soil

×

​

107

N:P:K (1:1:1) Fertilizer, EDTA

7.2 mg/kg

×

​

13.7 mg/kg

×

​

0.53

​

Sampanpanish et al., 2008

Tak Province, Thailand

Clay Loam

0-30

120

15-15-15

NPK

46.24 mg/kg

×

×

×

×

>1

Minh & Khoa, 2009

Danag,

Vietnam

Sand, Clay

×

90

×

0-60 mg/kg

×

2.95 mg/kg (shoot)

×

×

<1

Roongtanakiat & Sanoh, 2011

Phetchaburi, Thailand

Sandy Loam

×

120

×

14-6462 mg/kg

×

×

×

×

<1

Cadmium, Cd

Vetiver-based Phytoremediation Studies around the World

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Reference

Location

Soil

Sampling Depth

(cm)

Harvesting Period

(Days)

Amend-ments

Results

Before

After

Vetiver Uptake

Removal Efficiency

BCF

TF

Oshunsanya et al., 2012

Nigeria

Dumpsite

0-100

90

×

4.5

mg/kg

3.03 mg/kg

×

75-82%

×

>1

Abaga et al., 2014

Burkina Faso

Lixisol and Vertisol

0-20

180

×

2-10 mg/kg

×

21.8 mg/kg

×

2.3 & 22

0.38 & 7.3

Kriti et al., 2021

Delhi, India

Ni-Cd Battary Waste Cont Soil

×

120

Compost

30-120 g electrolyte waste

1156.1 mg/g

×

×

×

<1

Benavides et al., 2021

Pennsylvania, USA

Silt Loam

0-20

×

×

0.2-0.7 mg/kg

×

×

×

>1

×

Cadmium, Cd (Continued)

Vetiver-based Phytoremediation Studies around the World

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Reference

Location

Soil

Sampling Depth

(cm)

Harvesting Period

(Days)

Amend-ments

Results

Before

After

Vetiver Uptake

Removal Efficiency

BCF

TF

Pillai et. al., 2013

Kerala, India

Sandy Loam

×

60

Organic Manure

50-200 mg/kg

×

×

85-92.25%

×

×

Divya & Sushama, 2017

Kerala, India

Dump yard

×

365

×

​

115.67 mg/kg

49.6 mg/kg

×

×

3.21

1.1

Chintani et al., 2021

West Java, Indonesia

×

×

28

Urea, NPK

50-300 mg/kg

×

167.8 mg/kg

×

0.06-0.75

0.24-7.710

Chromium, Cr

Vetiver-based Phytoremediation Studies around the World

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Reference

Location

Soil

Sampling Depth

(cm)

Harvesting Period

(Days)

Amend-ments

Results

Before

After

Vetiver Uptake

Removal Efficiency

BCF

TF

Roongtanakiat & Chairoj, 2001

Thailand

Sand

×

120

15-15-15

Fertilizer

26.83-107.32 mg/kg

×

×

×

×

×

Sampanpanish et al., 2008

Tak Province,

Thailand

Clay Loam

0-30

120

15-15-15

NPK

25.89 mg/kg

26.00 mg/kg

×

×

×

×

Liu et al., 2009

Nanjing, China

Wasteland near Cu mine Area

×

60

Urea (1.5 g/kg soil) and KNO3 (1.587 g/kg soil)

0.95-173.08 mg/kg

×

×

×

×

<1

Abaga et al., 2014

Burkina Faso

Lixisol and Vertisol

0-20

180

×

100-500 mg/kg

×

4635 mg/kg

×

1.6 and 16

0.07 and 2.60

Vargas et al., 2016

El Cuadron La Union, Spain

Sandy Loam

0-20

365

Humic Acid

146 mg/kg & 6617 mg/kg

×

×

×

×

0.13-0.70

Copper, Cu

Vetiver-based Phytoremediation Studies around the World

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Reference

Location

Soil

Sampling Depth

(cm)

Harvesting Period

(Days)

Amend-ments

Results

Before

After

Vetiver Uptake

Removal Efficiency

BCF

TF

Roongtanakiat & Chairoj, 2001

Thailand

Sand

×

120

15-15-15

Fertilizer

23.98-95.92 mg/kg

×

×

×

×

×

Chantach et al., 2004

Mahasarakham, Thailand

×

0-30

84

×

​

22 mg/kg

×

​

​

×

×

<1

Wilde et al., 2005

Savannah,

USA

​

0-100

120

EDTA, NPA Fertilizer

300-4500 ppm/kg

×

1390-1450 ppm/kg

×

×

<1

Zhuang et al., 2007

Lechang,

China

Pb/Zn Mine Soil

×

107

N:P:K (1:1:1) Fertilizer, EDTA

119 mg/kg

×

155 mg/kg

×

0.01

×

Sampanpanish et al., 2008

Tak Province, Thailand

Clay Loam

0-30

120

15-15-15

NPK

87.96 mg/kg

28 mg/kg

​

×

×

×

Minh & Khoa, 2009

Danag,

Vietnam

Sand, Clay

×

90

×

0-700 mg/kg

×

74.65 mg/kg (shoot)

×

×

<1

Wu et al., 2010

Shaogua,

China

×

×

120

AMF and Refuse Compost

107 mg/kg

×

0.56-1.04 mg/seedlings

×

×

<1

Roongtanakiat & Sanoh, 2011

Phetchaburi, Thailand

Sandy Loam

×

120

×

14-6462 mg/kg

×

×

×

×

<1

Lead, Pb

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Reference

Location

Soil

Sampling Depth

(cm)

Harvesting Period

(Days)

Amend-ments

Results

Before

After

Vetiver Uptake

Removal Efficiency

BCF

TF

Andra et al., 2011

Texas and Baltimore,

USA

×

×

70

EDTA, EDDS

<1500 mg/kg

×

×

×

×

<1

Oshunsanya et al., 2012

Oyo,

Nigeria

Dumpsite

0-100

90

×

16.0

mg/kg

4.5 mg/kg

×

80-82.22%

×

<1

Bahraminia et al., 2015

Shiraz,

Iran

Sandy Clay Loam

0-30

120

AMF Fungi

50-800 mg/kg

×

×

×

×

<1

Attinti et al., 2017

Texas,

USA

Loam

0-15

300

EDDS

1000-2400 mg/kg

×

×

×

×

<1

Divya & Sushama, 2017

Kerala,

India

Dumpyeard Soil

×

​

365

×

​

82.24 mg/kg

93.88 mg/kg

×

×

0.35

0.5

Lead, Pb (Continued)

Vetiver-based Phytoremediation Studies around the World

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Reference

Location

Soil

Sampling Depth

(cm)

Harvesting Period

(Days)

Amend-ments

Results

Before

After

Vetiver Uptake

Removal Efficiency

BCF

TF

Divya & Sushama, 2017

Kerala,

India

Dump yard

×

365

×

35.54 mg/kg

32.62 mg/kg

×

×

2.10

0.60

Chintani et al., 2021

West Java, Indonesia

×

×

28

Urea, NPK

50-300 mg/kg

×

66.30 mg/kg

×

0.07-1.84

0.90-10.78

Kriti et al., 2021

Delhi,

India

Ni-Cd Battery Waste Cont. Soil

×

120

Compost

30-120 g electrolyte waste

699.00 mg/kg

×

×

×

<1

Nickel, Ni

Vetiver-based Phytoremediation Studies around the World

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Reference

Location

Soil

Sampling Depth

(cm)

Harvesting Period

(Days)

Amend-ments

Results

Before

After

Vetiver Uptake

Removal Efficiency

BCF

TF

Zhuang et al., 2007

Lechang,

China

Pb/Zn Mine Soil

×

107

N:P:K (1:1:1) Fertilizer, EDTA

93 mg/kg

×

269 mg/kg

×

0.06

×

Sampanpanish et al., 2008

Thailand

Clay Loam

0-30

120

15-15-15

NPK

2124.26 mg/kg

90 mg/kg

​

×

×

×

Roongtanakiat et al., 2009

Tak Province, Thailand

×

0-15

120

EDTA and DTPA

814 mg/kg & 5039 mg/kg

×

4.54-12.39 mg/pot

×

×

0.764

Wu et al., 2010

Shaogua,

China

×

×

120

AMF and Refuse Compost

107 mg/kg

×

2.36-3.70 mg/seedlings

×

×

<1

Roongtanakiat & Sanoh, 2011

Phetchaburi, Thailand

Sandy Loam

×

120

×

14-6462 mg/kg

×

×

×

×

<1

Vargas et al., 2016

El Cuadron La Union,

Spain

Sandy Loam

0-20

365

Humic Acid

146 mg/kg & 6617 mg/kg

×

×

×

×

0.056-0.125

Zinc, Zn

Vetiver-based Phytoremediation Studies around the World

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Vetiver-based Phytoremediation Studies in Bangladesh

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Location

Soil Type

(Based on Source)

Targeted Contaminants

Vegetation for Phytoremediation

Reference

Buriganga

Riverbank Soil

Cu, Cr, Pb, Ni, Zn

Vetiver Grass (Vetiveria zizanioides)

[1-3]

Buriganga

Riverbed Sediment

Cu, Cr, Pb, Zn

Indian Mustard (Brassica juncea) and French Marigold (Tagetes patula)

[4-5]

Munshiganj

Agriculture Land topsoil

As

Vetiver Grass (Vetiveria zizanioides)

[6]

Kallyanpur

Reclaimed Land

NH3, NO3, NO2, PO4, COD, pH

Vetiver Grass (Vetiveria zizanioides)

[7]

[1] Choudhury, M.R., Islam, M.S., Dey. P. and Parshi, F.N. Phytoremediation of heavy metal contaminated Buriganga riverbank soil by Vetiver grass (Vetiveria zizanioides), Draft Manuscript.

[2] Parshi, F.N. (2015). Strength-deformation characteristics of rooted soil, M.Sc. Engg. Thesis, Department of Civil Enggg., BUET, Dhaka, Bangladesh.

[3] Dey, P. (2016). Effect of Enhancement-amendment Addition on Heavy Metal Uptake Characteristics of Vetiver Grass from Soils of Hazaribagh Area, M.Sc. Engg. Thesis, Department of Civil Enggg., BUET, Dhaka, Bangladesh.

[4] Choudhury, M.R., Islam, M.S., Ahmed, Z. and Parshi, F.N. (2016). Phytoremediation of heavy metal contaminated Buriganga riverbed sediments using Indian Mustard and Marigold plants, Environmental Progress & Sustainable Energy, American Institute of Chemical Engineers (AIChE), Vol. 35, No.1, pp. 117-124

[5] Ahmad, Z.K. (2015). Phytoremediation of Heavy Metal Contaminated Soil Using Indian Mustard and Marigold Plant , M.Sc. Engg. Thesis, Department of Civil Engg., BUET, Dhaka, Bangladesh.

[6] Islam, M.S., Siddique, A.B., Islam, F. and Mallick, S. (2016). Arsenic problem in soil: a geo-environmental solution, Proc. of BUET-ANWAR ISPAT 1st Bangladesh Civil Engineering SUMMIT 2016 BUET, Dhaka, Bangladesh, pp. GE 55-GE61.

[7] Islam, M. S., Shams, S. M. and Sultana, F. (2018). Soil Waste Remediation Using Vetiver Grass., 4th International Conference on Advances in Civil Engineering 2018 (ICACE 2018), CUET, Chattogram, Bangladesh.

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Background

The Buriganga river, crucial to numerous economic activities in Dhaka, is experiencing severe soil quality degradation due to unrestrained wastewater discharge from various riverside industries, despite the immense economic value and reuse potential of brownfields, particularly from relocated tannery industries.

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Objectives

  1. To compare the growth of vetiver grass in heavy metal-contaminated Buriganga riverbank soil to that in normal garden soil and investigate the effects of the synthetic and organic chelating agent on the growth rate of vetiver grass.
  2. To assess heavy metal uptake by vetiver grass from the contaminated Buriganga riverbank soil under different chelate dosing conditions.

Phytoremediation of Buriganga Riverbank Soil

Contaminated Buriganga River Water

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Study Location

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Experimental Methods

Location

Bank of Buriganga River

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Sample

Specific gravity

LL(%)

PL (%)

PI (%)

OC (%)

Sand (%)

Silt (%)

Clay (%)

Buriganga Riverbank

2.62

47

22

25

2.0

13.0

75.0

10.0

Garden Soil

2.70

37

28

9

1.3

16.2

58

6.2

Soil Property

Four Soil Samples were analyzed: (i) Sand, (ii) Organic Clay-1, (iii) Mixed Soil (Sand & Clay), (iv) Organic Clay-2

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10

15

10

36 cm

52 cm

16

10

16

10

10

15

10

36 cm

52 cm

16

10

16

10

36 cm

52 cm

Experimental Methods

Indian Mustard

(Seed)

Vetiver Grass

(Clump)

Marigold Plants

(Seedling)

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VG Planation

VG, Week 8

VG, Week 4

VG, Week 12

VG, Week 20

Vetiver Grass Plot

Experimental Methods

Choudhury et al. (draft manuscript)

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Growth Study: Vetiver Grass

Shoot Height

Root Depth

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Initial Concentration in Soil

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Concentration in Vetiver Plant

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Concentration in Soil After Harvesting

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Growth Study: Vetiver at 13th Week

Leaf Height

Root Depth

Shoot Height

Measured Dimension (cm)

Soil Condition

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Summary

  • Despite significant uptake of contaminants by vetiver, the before and after scenario appears to be contradictory. The tray was filled with contaminated soil collected from the natural source and the distribution of contamination might not be homogeneous throughout the sample. This might be the fact behind such large variations (Islam, 2023).
  • The heavy metal uptake efficiency of vetiver grass is not as good as other locally available hyperaccumulators, its uptake efficiency can be substantially enhanced with application of chelating agents (EDTA or citric acid).
  • In case of EDTA, uptake efficiency did not increase significantly beyond a particular dosing value (1-2 mmol/kg of soil) and for higher value caused discoloration of leaves (Dey, 2016).
  • Uptake efficiency gradually increased with increasing dosing level of citric acid (Dey, 2016). But the uptake efficiency of heavy metals by using citric acid increased with increasing dosing level. From the analysis, it is evident that vetiver can be used as a continuous phytoextractor or phytostabilizer. However, it requires an in-depth analysis considering extent and level of treatment, life cycle analysis, survivability in various environmental and soil conditions, etc.

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Average high and low temperature: 26°C and 13°C

Average photosynthetic flux: 375 μmol m-2 s-1

Average relative humidity: 50%

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Sample

LL (%)

PL (%)

PI (%)

Specific Gravity (Gs)

OC (%)

Silt (%)

Clay (%)

Buriganga riverbed sediment

46

23

23

2.67

4-6

91.5

8.5

Garden soil

 49

 18

 31

 2.70

 -

 58

 17

Physical Properties of Buriganga Riverbed Sediments and Garden Soils

Phytoremediation of Buriganga Riverbed Sediment

Objectives

To compare the growth of Indian Mustard and Marigold in heavy metal-contaminated sediment with that in normal garden soil (control condition). To assess temporal variation in heavy metal uptake by Indian mustard and Marigold from the Buriganga riverbed sediment.

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Experimental Methods

French Marigold, Tagetes patula, seedling

MG, Seedling Plantation

IM, Seed Plantation

MG, Week 8

IM, Week 8

IM, Week 4

MG, Week 4

IM, Week 2

MG, Week 2

Indian Mustard, Brassica juncea, seed

Choudhury et al., 2016

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Growth Study: Indian Mustard

Weeks

Measured Dimension (cm)

Shoot Height

Root Depth

Root Mass Width

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Growth Study: Marigold

Weeks

Measured Dimension (cm)

Shoot Height

Root Depth

Root Mass Width

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Results and Discussions (Comparison)

Comparison of total uptake of Indian Mustard, Marigold, Vetiver Grass in 12-13 weeks time

(b)

(c)

Shoot

Root

100

0

-100

-200

-300

150

cm

-150

-250

50

-50

(a)

  • Vetiver has a lower efficiency of heavy metal uptake compared to Indian mustard and marigold plants. Marigold was observed to be more efficient for Cr, Pb, and Cu uptake, while Indian mustard was found to be more effective for Zn uptake (Choudhury et al., 2016).
  • However, vetiver showed better performance in uptaking Zn than marigold while it was similar to the effectiveness of Indian mustard. Here, the root depth of Indian mustard and marigold is about 10-15cm whereas the vetiver has a root depth of about 50-70cm.
  • Therefore, vetiver has an advantage of having a large and extensive root system with higher biomass compared to these plants, and this can lead to the remediation of contaminants from a deeper and wider influence zone.

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Background

Dhaka has 19 main discharge points, primarily located near canals and drains. Unfortunately, these areas have become dumping grounds for waste, which has resulted in a polluted environment rather than a refreshing one. The haphazard disposal of solid waste into low-lying areas and canals exacerbates the degradation of soil quality.

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Objectives

To assess the growth of vetiver in wasteland. To represent the effectiveness of plant in removing target contaminants (e.g., ammonia, phosphate, organic matter) from polluted soil and water.

Cleaning of Wasteland

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Experimental Setup

Details of the plantation

Schematic diagram of waste treatment by vetiver grass

Experimental Setup with Normal water

Experimental Setup with Wastewater

(Islam et al., 2018)

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Water Quality Parameters

Raw Wastewater

(mg/L)

Treated Water

(mg/L)

Percentage Removal

Percentage Generated

NH3

26.0

1.00

96

 

 

NO2

1.0

0.33

68

 

 

NO3

1.1

2.70

 

60

PO4

16.2

0.75

95

 

 

COD

81.0

176.0

 

 

54

pH

7.6

7.8

 

 

 

 

Quality parameters of wastewater and treated water

Results and Discussions

Specific Gravity

Liquid limit (%)

Plastic limit (%)

Shrinkage limit (%)

Plasticity index

2.55

40

22

26

18

Flow index

Co-efficient of uniformity

Co-efficient of curvature

Fineness modulus

Classification of soil

16

2.24

0.62

2.93

CL

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Findings of the Study

It was found that the wastewater contains NH3 of 26 mg/L, PO4-of 16.2 mg/L and the COD of 81.0 mg/L (Islam et al., 2018). Results from soil and water quality parameter tests reveal that vetiver removes NH3 and PO4- in substantial amount i.e., 96% and 95%, respectively. It means that vetiver can play a major role in remediating wasteland. It implies that vetiver-based phytoremediation technique can be useful for surface water treatment of contaminated khals.

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Background

  • Arsenic contamination from irrigation and mining is a significant issue in South and Southeast Asia, including Bangladesh, with the problem being particularly pronounced in anaerobic conditions of flooded paddy fields. This contamination has resulted in severe consequences for local communities.
  • Numerous studies have explored the remediation of arsenic contamination using local grasses and plants, but the potential of the vetiver plant for arsenic remediation remains to be fully investigated.

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Objectives

To observe the growth of vetiver grass in As contaminated agricultural top soil. To investigate the effectiveness of vetiver grass in As removal.

Arsenic Remediation

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Experimental Setup

Schematic Diagram Showing Vetiver Plantation

Vetiver Plantation in Nursery and Arsenic Contaminated Soil

Arsenic Contaminated Soil

Nursery Soil

22

6

22

6

6

24

6

36 cm

56 cm

(Islam et al., 2016)

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Findings of the Study

  • The growth of vetiver was better in the contaminated soil compared to the control soil which might be due to the higher nutrient content in the contaminated soil (Islam et al., 2016).
  • The arsenic content in the contaminated soil before plantation was found to be 18.8 mg/kg. After 6 months of plantation, it was found that arsenic contamination of the soil varies between 13.6 and 15.2 mg/kg. It means that vetiver can uptake As from the contaminated soil by 23% over time. Srisatit et al., 2003 also showed similar results.
  • However, the uptake is not significant, more research works are required including the additives such as EDTA, AMF, citric acid, etc. as indicated by Caporale et al., 2014.

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Research Gaps and�Future Direction

04

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Key Findings from Literature Review

  • The potential and effectiveness of vetiver grass in the removal of heavy metals, POPs, PCB etc., and its comparison with other methods and plants have been noticed in the reviewed articles. Moreover, the field experiment presented out of the reviewed articles proves that the vetiver-based phytoremediation technique is effective in the removal of contaminants.
  • The potential of vetiver grass in the removal of different heavy metals and toxins like dioxin, cyanide, TNT etc. has been assessed firsthand in different countries in field implementation.
  • Further lab and field experiments and monitoring are required to identify gaps, and application viability and to develop guidelines for safe and cost-effective technology.

Year: 2000-present

No. of Reviewed Articles: 52

Lab Experiment: 45

Field Implementation: 7

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Gaps in the Remediation Sector

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Knowledge Gaps

  1. Policy, Legislative and Regulatory Gaps
  2. In most cases, soil pollution is not legally defined or recognized.
  3. In several countries industrial activities that pollute soil are not consistently regulated.
  4. Securing fund is another gap.
  5. There are limitations in the creation of key institutions and/or integration between institutions.

2. Policy Gaps

  1. Slow or incomplete transfer of knowledge from scientists and enforcement agencies to policymakers
  2. The lack of generally accepted threshold values for toxicity assessment of priority and emerging contaminants

Main Constraints to Tackle Soil Pollution

  1. Lack of Awareness
  2. Socio-economic limitations
  3. Lack of national and local campaigns
  4. Lack of detailed studies
  5. Lack of Political Will and Illegal Waste Disposal
  6. Political pressures from other sectors, and the possible economic impact of control measures
  7. Illegal dumping and import of toxic wastes from other countries
  8. Lack of Infrastructure and Capacity

The Asia–Pacific region is very heterogeneous, with each country having different infrastructures and capacities for soil pollution management. These constraints often result in a technical inability to create and improve regional or global contaminant inventories.

FAO and UNEP. 2021. Global assessment of soil pollution: Report. Rome. doi.org/10.4060/cb4894en

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Standard Reporting Format

To have a complete idea of a study, a comprehensive and thorough reporting format should be followed where all the necessary data are collected and compiled in a standard way and using similar units. The following information can be collected to make the reporting useful and all-inclusive,

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  1. Geographical location with GPS
  2. Climatic data (rainfall, temperature, daylight, humidity, seasonal distribution etc.)
  3. Soil data (soil texture, pH, Cation Exchange Capacity (CEC), Electric Conductivity (EC), organic matter and nutrient content of the soil such as Total Nitrogen, Boron, Potassium, Phosphorus, Zinc)
  4. Season and duration of the study
  5. Details of amendments, if any (fertilizer, additives, fungi etc.)
  6. Concentration of heavy metals before treatment
  7. Concentration of heavy metals after treatment (during harvesting time and throughout multiple seasons)
  8. BCF, Concentration of Heavy Metals in plant Shoots and Roots, Phyto-method

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Way Forward and �Summary

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Way Forward

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  • Research and Development: Addressing soil contamination issues, particularly in Asian countries, requires focused research on the application of nature-based solutions at a field scale. This should involve a thorough investigation of various environmental and soil conditions, as well as the growth and effectiveness of different plants, to inform decision-making on the most suitable remediation options. Furthermore, a comprehensive analysis of existing contamination level assessment criteria is necessary to ensure their continued relevance. Consequently, political leaders and governments should allocate sufficient funding to this vital field of study, given its significant implications for human health and wellbeing.
  • Collaboration: To address soil contamination issues, a multi-disciplinary collaboration involving agricultural scientists, engineers, academics, and government agencies at both local and international levels is required. This collective effort is essential for developing effective guidelines, construction methodologies, and ensuring large-scale adaptation and successful application with active involvement from community members.
  • Resource Development: In addition to collaborative research, legislative enforcement is necessary for the assessment and identification of contaminated sites, which requires the development of resources including trained scientists, contractors, skilled labor, and equipment.

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Summary

  • Rapid economic growth in Asian countries, including Bangladesh, has led to increased urbanization and industrialization, causing significant environmental pollution, particularly with toxic and carcinogenic soil chemicals. In Bangladesh, soil and water contamination, primarily due to POPs and heavy metals has led to serious health concerns for local populations. Furthermore, land degradation and erosion have become significant geo-environmental issues in these regions. These issues are also hampering the SDGs. To mitigate these issues, it is critical to implement soil remediation measures and reduce land degradation and erosion, for which the author has extensively researched the use of vetiver grass as a nature-based solution, verified through lab tests, physical modeling, and field applications.
  • The author has explored the use of various plants and grasses, particularly vetiver grass, for the phytoremediation of heavy metals from different soils. Initially, vetiver's heavy metal uptake was lower compared to other local hyper-accumulators but improved significantly when chelating agents were introduced. They also assessed other plants like Indian Mustard and Marigold, with Marigold showing higher uptake efficiency for Cr, Pb, and Cu, while Indian Mustard was more efficient for Zn uptake. Despite its lower efficiency, vetiver grass has advantages such as a larger root system, higher biomass, and longer lifespan. However, to ascertain the suitability of these plants for wider use, comprehensive analysis considering treatment levels, life cycle, and adaptability to various geo-environmental conditions is required.

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  • Past research shows promise for the use of vetiver in soil remediation, particularly for heavy metal contaminants. Despite these encouraging findings, there is a lack of large-scale field applications and consistent reporting and assessment methodologies. Moreover, the current guidelines for soil contamination levels may be outdated. While phytoremediation, especially using vetiver, has proven effective in various geo-environmental conditions in lab experiments, broader implementation is constrained by these gaps.
  • Inconsistent reporting and assessment criteria also hinder its applicability. Hence, there exists significant potential for further research in this area to improve understanding and usability.
  • Legislative measures and public awareness are critical in tackling soil and water contamination. Addressing policy, legislative, and regulatory gaps, along with the mobilization of resources such as scientists, contractors, and skilled labor is crucial for effective remediation efforts. Further, political will and public engagement are necessary to reduce contamination levels and ensure the success of nature-based solutions.

Summary

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Thank You

Restoring Earth

Renewing Life