Remediation Strategies for elhi - isws.org.in · Remediation Strategies for Herbicide Residues Shashi Bala Singh Division of Agricultural Chemicals Indian Agricultural Research Institute

Remediation Strategies for Herbicide Residues

Shashi Bala SinghDivision of Agricultural Chemicals

Indian Agricultural Research InstituteNew Delhi-110012

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03/03/2017 ISWS-Conf., Udaipur

Indian Agriculture has made rapid strides since

independence

From food shortages and import

to self-sufficiency and exports.

India is

• Largest producer in the world of pulses , tea and milk

• Second Largest producer of fruits, vegetables, wheat , rice,

groundnut and sugarcane.

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India’s Agricultural Export Potentials

Marine Products

Rice

Wheat

Condiments and Spices

Cashew

Tea

Coffee

Castor

Processed food- honey, wine

Jute

Fruits and Vegetables- Onions, Mango, Grapes, Banana, Tomato , Potato , Litchi etc.

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Currently the level of their usage in the country is as low as 400 g per hectare as compared to Taiwan which uses 17,000 g, or Japan at 10,700 g or the 4,500 g in the US and the Europe 3,000 g per hectare.

ISWS-Conf., Udaipur

Inspite of that there is lot of hue and cry

Soils are contaminated

Water bodies are contaminated

Air monitoring are also on to detect toxicants

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Various studies from India indicate that residues of

herbicides are not a problem in food commodities.

In case of crop like wheat, rice, soybean, sugarcane

etc. there is always a long interval from application to

harvest of produce.

In case of vegetables also herbicides are applied

mostly as pre emergence and in post emergence also

not frequent sprays are given as in case of insecticide

or fungicides.

Thus the problem of herbicide residues in harvested

produce or food commodities is not much associated

with herbicide.

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But soils are of course much exposed to

herbicides.

Problem can be with most persistent herbicides in

field especially to crops in rotation.

However more residues in soil may be observed in

non crop areas, industry effluent and formulation

sites etc.

Herbicides with high water solubility and less

adsorption on soil particles can leach down to

ground water.

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Herbicides, a class of pesticides, is more common term to weed scientists

In 2010 very small number herbicide made

presence in the total number of pesticide .

In 2014 number was 61 out of 256

representing 26.1%.

In 2015 it was 70 in 261 representing 26.8%.

Now in 2016 it is 78 out of 275 representing

nearly 28.3% (Figure).


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Contamination with herbicides can be of two types

(i) Heavily contaminated sources which are generally at

the factory site (formulation or manufacture), filling

and vacating of spraying equipments which are pin

pointed sources.

(ii) Normal field soils which get contaminated by

repeated or over use of a herbicides, however this

varies from soil to soil and location conditions.

(iii) Non point sources, which are generally water bodies,

getting contamination by leaching or surface flow

from contaminated sites.


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A. Physical Adsorption Methods

Charcoal

Organic manure

Flyash

Biochars

Nanoclays

Modified clays

B. Bioremediation Methods

Microorganisms

Phytoremediation

Vermiremediation

Bio-stimulation

Enzymatic methods

C. Combined Technologies

Bio-beds

Prepared inoculums

Engineered microbes

Engineered plants


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Physical Adsorption Methods

Charcoal

Organic manure

Flyash

Biochars

Nanoclays

Modified clays


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Adsorption methods

Charcoal

Very good adsorbing material.

But adsorb different herbicides differently.

Specific questions to be addressed include:

1) the nature of AC: not all materials are equally well suited,

2) the long-term stability and sequestering potential of AC,

3) the optimal pollutant to AC fractions to be applied,

4) the time to reach equilibrium after amendment, and,

5) the ecotoxicological endpoints.

Some herbicides are strongly adsorbed on AC are not desorbed.

For those AC can be used for remediation from water.

In soil AC can bind the herbicide leaving the soil non toxic fit for plantation.


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II-Des

0

5

10

15

Atrazine Metribuzin Metolachlor Alachlor

% d

eso

rpe

d

I-Des

Atrazine and metribuzin werenot desorbed in any desorptioncycle Metolachlor and alachlor weredesorbed in first two cycles. Percent desorption of alachlorwas more than metolachlor

Desorption studies

Adsorption studies with Granular activated charcoal (GAC)

Studies were conducted with three cycles.

0

20

40

60

80

100

120

Atrazine Metribuzin Metolachlor Alachlor

% A

dso

rbe

d

In mixture the trend ofadsorption was metribuzin>atrazine> alachlor>metolachlor.

Triazines and Acetanilides

(Kumar YB, Singh N, Singh SB. 2013)03/03/2017 ISWS-Conf., Udaipur

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All the 4 sulfonyl ureas are highly soluble in water (1.2-2.8 g/L) Adsorption of two (metsulfuron and chlorsulfuron) on GAC was more than 95% in each cycle. Sulfosulfuron and chlorimuron could be adsorbed only 40-60% and there was a decrease in

adsorption after each cycle. Similarly desorption of metsulfuron and chlorsulfuron was very less (1-2µg/g) while other two

desorped in each cycle (5-23µg/g).

0

5

10

15

20

25

metsulfuron chlorsulfuron sulfosulfuron chlorimuron

De

sorp

tio

n (

µg

/g)

Pesticides

I Des

II Des

III Des

0

20

40

60

80

100

120

metsulfuron chlorsulfuron sulfosulfuron chlorimuron

% A

dso

rpti

on

Pesticide

I AD

IIAD

III AD

Study conducted with three sequential adsorption and desorption cyclesHerbicide studied: chlorsulfuron, chlorimuron, sulfosulfuron, metsulfuron

Sulfonylurea herbicides

Sulfonyl urea group includes herbicides that are ionisable, persistent and frequently found in ground and surface waters worldwide.

:

03/03/2017ISWS-Conf., Udaipur

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Conclusions

Triazinyl sulfonyl ureas were strongly adsorbed and least desorbed by

GAC thus can be removed from water

Primidinyl sulfonyl ureas were least adsorbed and more desorbed by GAC

thus may not be removed from water using GAC

Charcoal can also bind triazines and triazine substituted sulfonyl ureas in

soil and prevent leaching to the ground water.

metsulfuron sulfosulfuron

chlorimuronchlorsulfuron

Triazinyl SU Pyrimidinyl SU

(Singh SB, Raunaq, Kumar B. 2015)

Studies extended to soil using

organic manure, biochars and fly ashes

Sorption of atrazine and alachlor on soil columns amended with

organic manure increased in amended in comparison with the

unamended soils.

Biochars (Pyrolized material) behave differently depending upon the

parent material as well temperature at which ignition was done.

Biochars, which have high organic carbon content, specific surface

area and microporosity, have shown high herbicide retention capacity

and find use in managing the contaminants in environment.

Fly ash prevented leaching in soil.

(Singh N. 2003, 2006, 2008)

(Singh N, Raunaq and Singh SB. 2012, 2013), 2014


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Fly ash

Flyash have increased the adsorption of herbicides showing an inverse effect on

the leaching losses of herbicides with high water solubility.

Field evaluation of two fly ashes was done at recommended rate(40 t/ha)

on

persistence

mobility

bioactivity

of

metribuzin (water solubility=1.2g L-1) as pre-em at 0.5 kg ha-1

metsulfuron-methyl (water solubility=2.79g L-1) post-em at 8 g ha-1

in

soybean crop

wheat crop

No herbicide leached down to subsurface (15–30 cm) soil in fly ash

amended plots

Traces of herbicide (0.6–1.2 μg/kg) were recovered in subsurface soil

of fly ash unamended plot

No adverse effect on the bioactivity of herbicides and yield of

soybean and wheat

(Singh N, Singh SB, Raunaq and Das TK. 2013)03/03/2017 ISWS-Conf., Udaipur

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Nano organoclays are also widely used in

decontamination studies because of its high adsorption

capacity.

Natural polymer-nanoorganoclay composites were

prepared for the decontamination of pesticide industrial

effluent

CMC-DMDA composite showed the maximum adsorption

of atrazine (99.7%).

For further improvement in the removal efficiency of the

composites for atrazine, mixed clay composites were

prepared using CMC and combinations of organoclays

Method can be introduced as step in Industry effluent

treatment

However the problem of disposal of generated sludge

remains in question

Nanoclays and Modified clays

(Narayanan et al., 2016, 2017).03/03/2017 ISWS-Conf., Udaipur

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B. Bioremediation Methods

Microorganisms

Enzymatic methods

Bio-stimulation

Phytoremediation

Vermiremediation


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Soil: A store house of microbial activity

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Microbes are adapted to thrive in ‘adverse conditions’ of high

acidity/alkalinity/toxicity and high temperature.

They can develop ‘biological resistance’ against any toxic

substance in the environment due to special ‘jumping genes’.

Hence while a number of them may be killed due to high toxicity,

some resistant microbes survive and are cultured for further use.

Under favorable conditions of growth microbes can biodegrade/

biotransform the complex hazardous organic chemicals into

simpler and harmless ones.

After the use of ‘super bug’ in cleaning up oil spills, there has been

several successful stories of microbial technique in clean-up of

contaminated lands and Bioremediation of Contaminated Sites: A Low-

Cost Nature’s Biotechnology… 3 soils. (USGS, 1997).

The Microbiological Resource Centers (MIRCENS) at Cairo, Egypt is

examining the use of microbes in degrading persistent pesticides

pollutants. (UNEP Reports, 1996-2006).


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Studies by individual cultures from collection

Pendimethalin degradation was studied with 26 microbial cultures

procured from ITCC, Div. of Plant Pathology and Microbiology IARI.

Two fungal strains,

Fusarium oxysporum

Paecilomyces varioti

degraded pendimethalin quantitatively to two metabolites namely

N-(1-ethylpropyl)-3,4-dimethyl-2-nitrobenzene-1,6-diamine

3,4,-dimethyl-1,2-dinitroaniline

Rhizoctonia bataticola degraded it to

3,4,-dimethyl-1,2-dinitroaniline, latter metabolite.

Fungal degradation of pendimethalin involved

nitro reduction

dealkylation

(Singh and Kulshrestha, 1991)

(Kulshrestha and Singh, 1993)03/03/2017 ISWS-Conf., Udaipur

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In soil also the results showed that these two degradation

products were formed under non flooded soil.

However under flooded condition the partially reduced

product cyclised to give product IV03/03/2017 ISWS-Conf., Udaipur

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Long term application of pendimethalin over 5 years

indicated harvest time residues of 3% as against 18%

pendimethalin in the first year.

Rate of degradation of pendimethalin in laboratory

studies was much faster in herbicide treated field soil

compared to control untreated field soil.

Surface soil (0-15 cm) showed enhanced degradation of

pendimethalin that could be due to adaptability of the

aerobic microorganisms to degrade pendimethalin.

(Kulshertha et al., 2000)

Fusarium oxysporum, Paecilomycessp, Actinomyces sp., Aspergillus

niger, Bacillus megaterium, Pseudomonas sp., R. bataticola, A.

alternata were the microbes which were predominantly found in treated

soil

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Studies with microbes from acclimated environment

Mixed fungal culture isolated from metolachlor acclimated

field soil where metochlor was applied repeatedly for 3 seasons

It degraded metolachlor rapidly (t1/2- 3.5days)

Two strains Aspergillus flavus and A. terricola purified from

mixture

They degraded metolachlor upto 99% at a concentration of

100µg ml-1 to five metabolites

Predominant pathways involved in metabolism were

Hydrolytic dechlorination,

N-dealkylation and

Amide bond cleavage

(Sanyal and Kulshrestha, 2004)


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Aspergillus and Mucor sp. in broth degraded

anilofos.

Major degradation products identified were

o 4-chloro-N-isopropyl aniline

o 4-chloroaniline

(Kulshrestha and Singh, 1993).

Anilofos degradation was studied with 6 microbial cultures

procured from ITCC, Div. of Plant Pathology and Microbiology

IARI.

Studies by individual cultures from collection


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Studies by microbes isolated from field

Fusarium solani and Chaetomium globosum were isolated

from paddy soil where butachlor was applied

Butachlor metabolism was studied in the mineral salt medium

by these microbes.

F. solani transformed butachlor into six metabolites,

C. globosum formed four products.

Metabolism of this herbicide by these strains involved

Dechlorination,

Hydrolysis,

Dehydrogenation,

N‐dealylation,

O‐dealkyklation,

C‐dealkylation and

Cyclization

(Raut and Kulshrestha, 1997)


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Atrazine was applied to field in maize crop

No crop rotation

Every time maize was the crop

Atrazine was the herbicide

Continuously for 8 years

Observations

Poor weed control

Even with increased rate of application

Shift in weed flora

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Persistence studies in soil

Atrazine degradation was studied in field soil

Compared with control soil

Compared with sterile soil

Faster degradation in field soil (surface soil)

No effect of depth

Half-life decreased from 38 to 11 days

Indicated the microbial degradation

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Dilution technique

Characterization (with the help of Plant Pathology Division, IARI)

A fungal isolate- Penicillium sp.03/03/2017 ISWS-Conf., Udaipur

Source of energy

Full nutrient medium (C & N)

Minimal medium (-C & -N)

-C medium (only N)

-N medium (only C)

Less C medium (10% of the C + full N)

Less N medium (10% of the N + full C)

Less N medium was found to be appropriate

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Degradation of Atrazine in broth by acclimatized strain

Atrazine conc. Percent Degradation (20days)

5ppm 98%

10ppm 92%

20ppm 87%

100ppm 72%

200ppm 63%

500ppm 58%

1000ppm 40%

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0

20

40

60

80

100

0 5 10 15 20

Control

Treatment

Degradation of atrazine in sterile and non-sterile soil

60% degrd. in Penecillium treated sterile soil

4% degrd. in sterile cont

Net microbial contribution – 56%

Days

%remainig

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0

20

40

60

80

100

0 5 10 15 20

Days

Non Sterile Soil

Control

Treatment

Sterile Soil

39% degrd. in treated non-sterile soil

9% degrd. in non-sterile cont

Net microbial contribution – 30%

Little inhibition was seen from native microbial population

(Singh and Kulshrestha, 2008)


N

N

N

C2H5HN NH

Cl

CH

CH3

CH3

N

N

N

H2C=HCHN NH

Cl

CH

CH2

CH3

N

N

N

OH

C2H5HN NH CH

CH3

CH3

N

N

N

H2N NH2

Cl

2-chloro-4,6-di amine-s-triazine

2-hydroxy atrazine

ATRAZINE (1)

(2)(3)

(4)

Identified microbial degradation products

On the basis of

Mass spectral analysis

Comparison with authentic samples

(Singh et.al., 2008)

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Alachlor degrading microorganism was isolated from the soil whichwas fortified with alachlor in laboratory at regular intervals

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Added alachlor@ 0.5ug/g 4 times

at 5 days interval

Left for 20 days

Added alachlor@ 1.0ug/g 4 times at 5

days interval

Incubated aerobically for 4 months

Moisture mainatined

Soil

SOIL ENRICHMENT

Studies with microbes from artificially acclimated

environment: Laboratory acclimation


Taken 5g enriched soil

Added 45 ml of

sterile waterSoil

Aqueous layer

Aliquot used

Serially diluted

For bacteria(10-9)

For fungi (10-3)

For actinomycetes (10-5)

ISOLATION OF MICROORGANSMS

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Identified a predominant fungal strain Rhizopus oryzae


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0

45.79

58.9

81.14

98.14

100

0

42.99

55.2

74.26

95.6

98.3

0

7

15

25

40

50

Tim

e (

Days)

Percent Degradation

Non-sterile soil

Sterile soil

Degradation of alachlor in sterile and non-sterile

soil by Rhizopus oryzea (pure fungal isolate)

By adding this strain to soil half life of alachlor degradation reduced from 22 days to 9.5days

This could utilize alachlor as N source

Not much inhibition was seen from native microbial population

(Maisnam Jaya et.al., 2017)03/03/2017 ISWS-Conf., Udaipur

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Alachlor microbial degradation products identified by GC-MS


Enzymatic methods

Crude enzyme extracted

Atrazine degradation studied

with CFE @ 50ppm

at two concentrations of CFE

were used

mycelia growth was harvested

filtered through a sterilized muslin cloth

grinded the mycelium withbuffercontaining 10mM β-mercaptoethanol

and 0.1mM PMSF

washed the mycelium

centrifuged at 11,000 rpm


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52% degradation was observed in 96 hours of incubation.

Degradation increased with increased CFE concentration.

Incubation for 26 hours revealed only one metabolite i.e. hydroxy atrazine

In 96 hours, more hydrophilic metabolite III was seen.

(Singh et.al., 2008)03/03/2017 ISWS-Conf., Udaipur

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Bio-stimulation

Bio-stimulation basically involves the stimulation

of microorganisms already present in the soil, by various means.

This can be done by many ways:

i. Addition of nutrients such as nitrogen and phosphorus.

ii. Supplementation with co-substrates e.g. methane added to degrade

trichloroethylene.

iii. Addition of surfactants to disperse the hydrophobic compounds in

water.

iv. Addition of bio-surfactant producing microbe in consortium


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The three isolated colonies from bifenthrin(insecticide) contaminated soil

BF2- Aspergillus flavus by Division

of Plant Pathology, IARI

BF3 - A non-sporulating fungi

which was characterized by molecular

techniques(DNA analysis) as

Achartomium strumarium (Accession

No. JN169753)

BF1 - Aspergillus niger by Division

of Plant Pathology, IARI


Degradation in broth, sterile and non sterile soil by pure Serratia marcescens,L-11 culture

PAH degrader Bio surfactant producing strain But not good degrader

of bifenthrin

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Rate constant

(K)

Correlation

coefficient(r)

Half-

life

(Days

)

Serratia

marcescens,L-112.85×10-3 0.970

2.03×10-2 0.986

2.26×10-2 0.992

Consortium M-1:Aspergillus flavus and Achaetomiumstrumarium

Consortium M-2: Aspergillus flavus, Achaetomium strumariumand Serratia marcescens, L-11


Enhanced degradation of bifenthrin in broth by mixed cultures

0

10

20

30

40

50

60

70

80

90

100

0 10 20 30

% D

egra

dati

on

Time (Days)

control

M-1

M-2

86.9

Rate

constant (K)

Correlation

coefficient(r)

Half-life

(Days)

5.78×10-2 0.968

6.90×10-2 0.992

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Enhanced degradation of bifenthrin in sterile and non sterile soil by mixed cultures

1. Sterile Soil

Half-life (Days)

Sterile soil

Half-life (Days)

Non-sterile soil

69.5

0

10

20

30

40

50

60

70

80

0 10 20 30

% D

egra

dati

on

Time(Days)

Control M-1 M-2

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0

10

20

30

40

50

60

0 10 20 30

% D

egra

dati

on

Time(days)

Control M-1 M-2

2. Non Sterile Soil

T1/2=147 days

(Divya Sharma, 2012). 03/03/2017 ISWS-Conf., Udaipur

Identification of degradation product and proposing the metabolic pathway

CH3

CH3

CF3

ClO

O

CH3

CH3

CH3

O

OH

CF3

Cl CH3

OH

CH3

HOOC

Bifenthrin

B A

C

4 Unknown products +

Mixed microbial culture

Mixed microbial culture

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Phytoremediation is ‘green bioengineering technology’ for environmental

cleanup that uses plants to remove pollutants from the soil or to render them

harmless.

It takes advantage of the natural abilities of plants to take up, bioaccumulate,

store or degrade organic or inorganic substances.

They are costeffective, aesthetically pleasing, passive, solar-energy driven and

pollution abating nature’s biotechnology.

Such plants are adapted to thrive in very harsh environmental conditions of soil

and water absorb, tolerate, transfer, assimilate, degrade and stabilize highly toxic

materials from the polluted soil and water.

The organic pollutants may ideally be degraded to simpler compounds like

carbon dioxide (CO2) and water (H2O), thus reducing the environmental toxicity

significantly.

Possibly due to their static (non-mobile) nature, plants had to evolve their

survival modes even in odd environments including lands contaminated with

xenobiotic substances.

Phytoremediation


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1. Sunflower (Helianthus anus);

2. Vetiver grass (Vetiveria zizanioides);

3. Indian Mustard (Brassica juncea)

4. Poplar tree (Populus Spp.);

5. Brake fern (Pteris vittata)

6. Barmuda grass (Cynodon dactylon);

7. Bahia grass (Paspalaum notatum);

8. Cumbungi (Typha angustifolia);

9. Redroot pigweed (Amaranthus

retroflexus);

10. Kochia (Kochia scoparia);

11. Foxtail barley (Hordeum jubatum);

12. Switch grass (Panicum variegatum);

13. Musk thistle (Carduus nutans);

14. White raddish (Raphanus sativus);

15. Catnip (Nepeta cataria);

Important Plant Species Identified for

Phytoremediation Works 16. Big bluestem (Andropogan gerardii)

17. Alpine pennycress (Thlaspi Spp.);

18. Canada wild rye (Elymus candensis)

19. Nightshade (Solanum nigrum);

20. Wheat grass (Agropyron cristatum)

21. Alfa-alfa (Medicago sativa);

22. Tall Fescue (Festuca anundinacea)

23. Lambsquarters (Chenopodium

berlandieri);

24. Reed grass (Phragmites australis);

25. Tall wheat grass (Thynopyron

elongatum);

26. Rhodes grass (Chloris guyana);

27. Flatpea (Lathyrus sylvestris);

28. Carrot (Daucus carota)

29. Willows (Salix viminalis)

30. Periwinkle (Cathranthus roseus)

Most of them are weeds- A great opportunity for weed scientists


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Studies with herbicides C14 -metsulforon methyl, C14 – atrazine, C14

– 2,4 D in soil have shown that worm vermicasts sorbed higher amount

of herbicides from the contaimated soil than the control soil (without

worms).

This is due to the higher levels of organic carbon & more finer size of

fractions in worm worked contaminated soils.

Increased agrochemical sorption due to worm activity was also

studied by other authors for C14 – atrazine and C14 – metolachlor in

organic rich earthworm burrow linings.

Vermiremediation

(Bolan & Baskaran 1996)

(Hickman & Reid, 2008).


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Earthworms (Aporrectodea longa) applied@ 5 worms per 2 kg of soil

contaminated with non-extractable herbicides (C14 - isoproturon, C14 –

dicamba and C14 – atrazine) residues in soil for 28 days.

Due to earthworm burrowing actions, a greater degree of previously

bound pesticides residues in soil was released as compared to those

without worms.

Enhanced the release and mineralization of bound herbicide residues

Similarly when herbicides in soil were freshly added, the non-extractable

residues of C14 - isoproturon, C14 – dicamba and C14 – atrazine were

higher by factors 2, 2, and 4 respectively in the soil without worms.

Restricted the formation of bound fraction of herbicides

Very significant action from the bioremediation point of view

(Gevao et, al., 2001)

Effect on bound residues


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Vermiremediation of different herbicides in soil

performed by some earthworm species

Herbicides Earthworm species involved

Effect

Atrazine, 2,4-D and Metsulforonmethyl

L. rubellus and A. calignosa

Casts increased sorption of compounds

Atrazine and Metolachlor

L.terrestris Increased sorption of compound to burrow linings

Atrazine A. giardi Burrows and casts increased compound sorption


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C. Combined Technologies

Bio-beds

Prepared inoculums

Engineered microbes

Engineered plants


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On-Farm Remediation of Pesticide Wastes using

Biobeds

Herbicide waste disposal on farms during filling or vacating the

sprayers is a pin pointed pollution source and a concern for

agriculturalists

Improper disposal of leftover pesticide mixtures from sprayer

operation or cleaning, as well as spills during loading can

contaminate wetlands, ponds, waterways, or drinking water wells.

Biobeds and other similar systems are intended to bind and

biodegrade point sources of plant protection products.


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In its simplest form a biobed consists

of a clay-lined hole filled with a mixture

of top-soil, peat or compost and straw.

The top-soil serves as the source for

the microorganisms in the system.

The peat or compost is included for

its high water-holding capacity and

provides a large organic matter surface

area for adsorption

The straw serves as a carbon source

for lignin-degrading microorganisms.

A typical system of Biobeds


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Name for the

bioremediation system

Country

BiobedSweden and most other

countries

Biofilter Belgium

Biomassbed Italy

Biodep Guatemala

Phytobac® and BiobacFrance and some other

countries

Vertical Green Biobed Switzerland

Biobeds originated in Sweden as a response to the need for

simple and effective methods to minimize environmental

contamination from pesticide use, especially when filling

spraying equipments.

They are now adapted to the conditions in other countries

where they have also changed name.


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Bio-augmentation in Soil Bioremediation

Addition of specific microorganisms to the polluted soil

constitutes bio-augmentation.

The pollutants are very complex molecules and the native soil

microorganisms alone may not be capable of degrading them

effectively.

So the potential microbes are added to the soil.

Many a times microbes are engineered for specific

degradation and then added.


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Genetically Engineered Bacteria Capable of

Destroying Some Hazardous Chemicals

S.No. Bacterium Chemicals Destroyed

1. P. putida Camphor degradation

2. P. oleovarans Alkane degradation

3. P. cepacea 2,4,5 – T degradation

4. P. mendocina Trichloroethylene

degradation

5. P. diminuata Parathion (pesticide)

degradation


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Dr. Gita KulshresthaDr. Shashi P. LalDr. Neera SinghDr. Lata NainDr. Jaya MaisnamDr. Divya SharmaDr. Priyanka ChoudharyDr. Neethu NarayanMs. RaunaqDr. Birendra KumarMr. Pawan Kumar

Acknowledgements

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Thank you for patient listening………………………

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Documents

Remediation Strategies for elhi - isws.org.in · Remediation Strategies for Herbicide Residues Shashi Bala Singh Division of Agricultural Chemicals Indian Agricultural Research Institute