WELCOME

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Ecological fate of chemicals used in agriculture

II SEMINAR

Sundaresh

UHS13PGM396

Sr. M.Sc.(Hort.) Plant Pathology

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Topic division • Definitions

• Pesticide usage

• Fate of pesticides in environment

• Effects of pesticides

• Pesticide tragedies

• Control measures

• Reviews

• Conclusion

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Ecology

• At community level, ecology can be defined as complex interactions that exist among interdependent organisms that cohabitate the same geographical area and with their environment

• At individual level, it entails the relationships that exist between particular individual with numerous physical and biological factors

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Fate ?

• Developments of events outside a person’s control

• Life cycle of a chemical (pesticide) or biological (enzyme) pollutant after its release in the environment

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Losses caused by different pests

7 IIVR Extension Bulletin

Agriculture pollution

• Contamination of soil, air and water environments due to farming activities

The primary agricultural pollutants are:

Nutrients(Nitrogen and phosphorus)

Pesticides

Sediments

Salts

Wastes

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Pesticides?

• A substance used for destroying of pests (insects or other organisms) harmful to cultivated plants or animals

• A pesticide is any substance or mixture of substances specifically intended to prevent or repel or destroy or lessen the effect of a pest

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Pesticides includes

Herbicide Insecticide Nematicide Rodenticide Bactericide

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Fungicide Disinfectant Repellent Sanitizer…….etc

Share (%) of different classes of pesticides used in India

11 IIVR Extension Bulletin

Pesticide consumption (a.i., kg/ha) in different countries

12 IIVR Extension Bulletin

13 http://www.krishijagran.com

Fate of pesticides in environment

Transfer Processes

Adsorption

Volatilization

Spray Drift

Runoff

Leaching

Absorption

Breakdown Processes

Microbial breakdown Chemical breakdown Photo degradation

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Adsorption • Adsorption is the binding of pesticides to soil particles

• The amount a pesticide is adsorbed to the soil varies with the type of pesticide, soil moisture, soil pH and soil texture

• Pesticides are strongly adsorbed to soils that are high in clay or organic matter

• They are not strongly adsorbed to sandy soils

• Most soil-bound pesticides are less likely to give off vapours or leach through the soil

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Volatilization • Volatilization is the process of solids or liquids

converting into a gas, which can move away from the initial application site

• Pesticides volatize most readily from sandy and wet soils

• Hot, dry or windy weather and small spray drops increase volatilization

• Incorporation of the pesticide into the soil can help reduce volatilization

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Spray drift • Spray drift is the airborne movement of spray droplets away

from a treatment site during application

• Spray drift is affected by:

Droplet size – smaller- more likely they will drift

Wind speed – stronger- more pesticide spray will drift

Distance between nozzle and target plant or ground

• Drift may also hazard to people, domestic animals, pollinating

insects

• Drift can contaminate water bodies like ponds, streams, and

ditches; harm to the fish or other aquatic plants and animals 19

Runoff • Runoff is the movement of pesticides in water over a

sloping surface

• The pesticides are either mixed in the water or bound to

eroding soil

• Runoff can also occur when water is added to a field

faster than it can be absorbed into the soil

• Runoff from areas treated with pesticides can pollute

streams, ponds, lakes, and wells

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• Pesticide residues in surface water can harm animals and contaminate groundwater

• Water contamination can affect livestock and crops downstream

• Pesticide losses from runoff are greatest when rains heavily right after the spray

• Reduce the chances of runoff by watching the weather forecast

• If heavy rain is expected, delay spraying to avoid runoff

• Irrigate according to label instructions

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Leaching

• Leaching is the movement of pesticides in water

through the soil

• Leaching occurs downward or sideways

• Groundwater may be contaminated if pesticides

leach from treated fields, mixing sites, washing

sites, or waste disposal areas

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Absorption • Uptake of pesticides and other chemicals into

plants or microorganisms

• Pesticide residues may be broken down or remain inside the plant or animal, when the animal dies or as the plant decays released back

• Some pesticides stay in the soil long enough to be absorbed by plants grown in a field years later

• They may damage or leave residues in future crops

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Degradation or Breakdown Processes

• Microbial breakdown is the breakdown of chemicals

by microorganisms such as fungi and bacteria

• Chemical breakdown is the breakdown of pesticides

by chemical reactions in the soil

• Photo degradation or Photolysis is the breakdown of

pesticides by sunlight. All pesticides are susceptible to

photo degradation to some extent

• Hydrolysis: Water also degrades pesticides by dividing

large molecules into smaller ones

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Pesticide dissipation in the environment

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How fast and which pathway predominates depends on

chemical properties and environmental condition

Biomagnification

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• The accumulation of more toxin in the bodies of organisms as move you from producers to primary consumers and then secondary consumers etc.

• It occurs when a chemical becomes more and more concentrated as you move up a food chain

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Review-1

Study on Bioaccumulation of Lindane in Various Tissues of Channa gachua from Aurangabad

District, India

(Shingare et al., 2009)

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Concentration of lindane in liver, kidney and body muscle of Channa gachua fish

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Review-2

Environmental Fate of Maneb

-Elizabeth Downing, 1999

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Review-3

Isolation of Bacteria for Degradation of Selected Pesticides

(Hussaini et al., 2013)

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Collection of soil samples (Maharashtra)

Isolation and Biodegradation

Characterization of bacterial isolates

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Study focuses on the isolation and characterization

of bacterial cultures for biodegradation of

pesticides commonly used in the agriculture

Sl.

No.

Isolates Identified cultures

1 B6 Acinetobacter radioresistens

2 B11 Pseudomonas frederiksbergensis

3 B12 Bacillus pumilus

4 B14 Serratia liquefaciens

5 B15 Serratia marcescens

6 B17 Burkholderia gladioli

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Per cent Pesticide degradation by the isolated

cultures

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Isolates Methyl

parath

ion

Endos

ulfon

Chloro

pyrifos

Igepa

l CO-

210

Dime

thoat

e

Mal

athi

on

Dia

zin

on

Acinetobacter

radioresistens

-- -- 38 -- -- 01 --

Pseudomonas

frederiksbergensis

10 04 -- -- 04 09 --

Bacillus pumilus -- -- 15 08 37 45 --

Serratia liquefaciens -- -- -- -- - 11 51

Serratia marcescens 01 -- 08 02 -- -- 34

Burkholderia gladioli -- -- -- -- 03 -- --

Ecological effects of pesticides

Explained the environmental problems associated with

indiscriminate use of pesticides

• “Silent Spring” published in 1962

• Chemical and pesticide industry alarmed by book’s

success

• “Most influential book” on environmental movement 36

Ecological effects of pesticides

• Loss of species diversity among the food

chains and food webs

• Effects on pollinators

• Effects on nutrient cycling in ecosystem

• Effects on soil erosion, structure and fertility

• Effects on water quality

• Effects on human beings

• Effects on birds

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Contd…

• Contaminate the food • Effects on fish and other aquatic organisms

• Pesticides disrupt the natural balance between pest and

predator insects

• Pesticides cause pest rebound and secondary pest outbreaks

• Pesticides may cause pest resistance

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Effects on pollinators

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Effects on water quality

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Dissolved pesticides in various river water in south Asia

(James, 2000)

Name of

State

No. of Water

bodies

Rive

r

Lake/Tank/

Drain etc.

Andhra Pradesh 8 3 5

Assam 2 2

Delhi 1 1

Jharkhand 1 1

Gujarat 10 9 1

Haryana 3 2 1

HP 2 1 1

Karnataka 6 4 2

MP 5 4 1

Maharashtra 15 15

Meghalaya 5 1 4

Orissa 5 5

Punjab 3 3

Rajasthan 3 3

TN 7 7

Sikkim 1 1

UP 8 8

WB 1 1

TOTAL 86 71 15

Agrawal et al., 2010

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State wise polluted stretches in rivers and lakes in India

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Review- 4

Pesticide Pollution: Trends And Perspective

Anonymous, 2001

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Levels of DDT and HCH content in human blood

samples in general population in India

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City Year No. of

Samples

Total

DDT

(ppm)

Total

HCH

(ppm)

Lucknow 1980 25 0.02 0.022

Delhi 1982 340 0.71 0.49

Lucknow 1983 48 0.028 0.075

Delhi 1985 50 0.301 --

Ahmedabad (Rural) 1992 31 0.048 0.148

Ahmedabad (Urban)

1997 14 0.032 0.039

Levels of DDT and HCH residues in human fats samples in general population in India

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Levels of DDT and HCH residues in human

milk samples in general population in India

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Reproductive performance of persons involved in spraying operation

• Data on reproductive toxicity were collected from 1,106

couples when the males were associated with the spraying of

pesticides (OC, OP and carbamates) in cotton fields.

Analysis of the reproductive performance

• A cytogenic study revealed a significant increase in chromatid

breaks and gaps in chromosomes in the workers exposed to

pesticides.

Abortion 15 %

Still births 2.6 %

Neonatal deaths 2.2 %

Congenital defects 0.1 %

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Review-5

Residues of DDT and its metabolites in

human blood samples in Delhi, India

Agarwal et al., 1976

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Concentrations of DDT and its metabolites in human whole blood samples from Delhi, India

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Contaminate the food

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Review - 6

Challenges of limiting pesticide residues in fresh vegetables: The Indian experience

Karanth, 2002

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Extent of pesticide contamination in

vegetables in Mysore City (%)

Total number of samples tested over 4 seasons: 514

Crop Nil HCH DDT HCH + DDT

Tomato 0 72 14 14

Egg plant 44 15 25 16

Chilli 0 57 28 15

Peas 40 39 11 0

Cow pea 14 70 12 4

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Pesticide residues (ppm) in market samples of fruits and vegetables

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Accelerated degradation of HCH in soil with application of

Agrocure (residual HCH in soil - ppm)

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Dose

applied

Without

Agrocure

With

Agrocure

Extra HCH

degraded

(μg/g)

Accelerated

degradation

(%)

30

days

90

days

30

days

90

days

30

days

90

days

30

days

90

days

50 ppm 24.8 1.4 15.7 1.1 9.1 0.3 36.7 21.4

100 ppm 57.4 2.1 37.2 1.5 20.1 0.6 35.1 28.6

Efficacy of Baxeklen in the removal of HCH

from vegetables

Crop Residue

Burden

μ/100g

Residues

removed

μ/100g

% removal

Radish 26.6 22.8 87.0

Carrot 90.7 67.0 73.0

Lady’s finger 38.4 27.5 71.6

Tomato 10.4 9.1 87.5

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Review - 7

Persistent chlorinated pesticide residues in selected market vegetables of root and leaf

origin

Kumar et al., 2012

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Concentrations (range and mean) of aldrin, dieldrin, heptachlor and lindane in selected vegetables

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Pesticide Min Max Mean SD SE* %

Aldrin <0.01 1.58 0.48 0.48 0.06 22

Dieldrin <0.01 .080 0.13 0.16 0.02 6

Heptachlor <0.01 2.80 1.03 0.83 0.11 48

Lindane <0.01 1.59 0.52 0.46 0.06 24

Total OCPs <0.01 6.00 2.16 1.61 0.21 100

Concentrations (range and mean) of aldrin, dieldrin, heptachlor and lindane in Sugar beet, Fenugreek and Coriander leaves

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MRLs for pesticide in vegetables: Comparison with of this study

ng/g Organochlorine Pesticide compounds

Aldrin Dieldrin Heptachlor Lindane

MRLs (maximum residual limits)

Europe 10 10 10 50

Indian 100 100 50 1000

Present

study

0.48 0.13 1.03 0.52

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Safeguards • Practicing Integrated Pest Management (IPM)

• Only using pesticides that are labelled for the intended crop

and pest

• Considering application site characteristics (soil texture, slope,

organic matter)

• Considering the location of wells, ponds and other water

bodies

• Measuring accurately

• Maintaining application equipment and calibrating accurately

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• Mixing and loading carefully

• Preventing back siphoning and spills

• Considering the impact of weather and irrigation

• Storing pesticides safely and securely

• Disposing of wastes safely

• Reducing off-target drift

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Pesticide tragedies

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• Aerial spraying of Endosulfan since 1976 in cashew

plantations spread over 4500 hectares three times in

a year around 15 villages in Kasaragod district

• The cashew plantations belong to the state owned

public sector company – Plantation Corporation of

Kerala (PCK)

• Aerial spray of Endosulfan using helicopters was

recommended by Government scientific bodies to

cut cost of manual labour

Kasargodu Endosulfon tragedy

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• Endosulfan has been banned by the

Supreme Court of India w.e.f. 13-05-2011 for

production, use & sale, all over India

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Bhopal Gas Tragedy • Bhopal’s pesticide plant was built in 1969 to manufacture Sevin, a

pesticide used throughout Asia to kill beetles, weevils and worms

• The plant was operated by Union Carbide India, Limited, but an American company, Union Carbide Corporation, held more than half the stock

• The leak began on December 2, 1984, when water entered a tank that was used to store methyl isocyanate, a toxic gas and a key ingredient in Sevin

• The water reacted with the gas, causing extreme pressure and heat that possibly caused the tank to explode.

• The tank spewed 40 tons of poisonous gas into the air. The toxic cloud was mostly methyl isocyanate, a compound that can irritate the throat and eyes, cause chest pain and shortness of breath, and, in large doses trigger convulsions, lung failure and cardiac arrest 66

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Conclusion

• In modern agriculture use of pesticides is a must, but proper and efficient use has to be done

• To save current and also future generation, ecology; judicious use of chemicals is recommended

• Alternative strategies- Bio-pesticides, IPM

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