The document discusses the negative environmental impacts of pesticide use in agriculture. It notes that pesticides can persist in soil and water for long periods of time, killing beneficial organisms and contaminating ecosystems. Their overuse has led to issues like pest resurgence and the development of resistance. The document also examines the health hazards of pesticide exposure through soil, water and air to humans and other organisms. Long-term effects on farmers and communities have included increased rates of cancer, neurological and respiratory diseases. Proper regulation and alternative methods of pest control are needed to reduce these risks.

1. Problems associated with pesticides
in agriculture,
Pesticide Persistance & Pollution,
Health hazards & their side effects
Safeena Majeed, A. A.
PA1TAH082

2. Introduction

3. Improving productivity
Quality of food Vector disease control
Crop protection

4. EFFECT OF AGROCHEMICALS
• Soil
• Water
• Air
• Human health

5. 1.SOIL HEALTH
Soil health is the capacity
of soil to function within
ecosystem & land use
boundaries, to sustain
productivity, maintain
environmental quality, and
promote plant and animal
health.

7. NEGATIVE IMPACTS OF
PESTICIDES ON SOIL HEALTH
• Kills beneficial organisms.
• Increase in nitrate levels of soils.
• Damage natural make up of soil.
• Alters the pH.
• Decrease soil quality.
• Kills soil organisms.
• Toxic to microbes.
• Toxicity availability of nutrients.
• Kills earthworms.
• Residual effect.
• Toxic to soil organisms.

8. 2.EFFECT ON WATER
• The runoff of
agrochemicals into
streams, lakes, and
other surface waters
can increase the growth
of algae.
• Eutrophication- Change
in quality and
composition of aquatic
ecosystems by
accumulation of
excessive chemicals in
water bodies.
• Water become unfit
for drinking.

9. • Polluted water
leading to the
death of fish and
other aquatic
animals.
• Excessive use of
agrochemicals has
led to the
contamination of
groundwater .

10. Pesticide concentration in ground water
Close et al., 2010

11. PESTICIDE PATHWAY ENTERING
WATER
Routes of pesticides to
reach the water
1. Drift outside of the
intended area when it is
sprayed
2. Percolate, or leach,
through the soil,
3. Carried to the water as
runoff or spilled
accidentally or through
neglect.
4. They may also be carried
to water by eroding soil.

12. Navarro et al., 2007
Leaching distance of pesticides v/s coefficient of
distribution in soil (Kd)

13.  Ability of a pesticide to remain present
and active for a long time
 Provides for long-term pest control, but
may harm sensitive plants and animals
 May lead to illegal residues on rotational
crops
Persistence

14.  Pesticide persistence often is expressed in terms
of half-life.
 This is the length of time required for one-half of
the original quantity to break down.
 Based on this 3 types :
1. Non-persistent pesticides: <30 days
2. Moderately persistent pesticides:30 to 100 days
3. Persistent pesticides: >100 days.

15. Organochlorines- toxicity & persistance

16. Continued….
Jayaraj et al., 2016

17.  Persistence in soil may vary greatly wrt
degradation influenced by a number of factors,
determined by specific local conditions.
 Ultimately, the degradation products - water,
CO2 and minerals.
 However, intermediate degradation products
of some pesticides are of concern for health
or environmental reasons.
 In these cases, half-life values should be
determined for the intermediate products.

18. Factors influencing the fate of
pesticides in soil
Kerle et al., 2007

19. Kerle et al., 2007

20. Pesticide disappears from soil in 3 steps
1. Acclimation phase- prior to the degradation, a
period is noted in which no disappearance on the
compound is evident
 Sometimes it is adaptation or lag period -length of time
between the addition or entry of the pesticide into the soil
and evidence of its detectable loss
2. Dissipation phase- no change in concentration is
noted but then the disappearance becomes evident
and the rate of loss often becomes quickly
3. Persistence phase- which is longer, and is expressed
in units of time: hours, days, weeks, months and even
years.

21. Navarro et al., 2007

22. Pesticide Characteristics
Solubility
 The ability of a pesticide to
dissolve in a solvent, usually
water
 Soluble pesticides are
more likely to move with
water in surface runoff or
through the soil to
groundwater

23. Pesticide Characteristics:
Adsorption
Binding of chemicals to soil particles
 Higher with oil-soluble
pesticides
 Clay and organic matter
increase binding
 Decreases the
potential for a
pesticide to move
through soil

24. Pesticide Characteristic:
Volatility
the tendency of a pesticide to turn into a
gas or vapor
Temperature
Wind
Humidity
=
Higher
Volatility

25. Pesticide Characteristics:
Volatility
 Fumigants volatilize and move gas through soil,
structures or stored commodities
 Several herbicides are quite volatile and
pose harm when the vapor moves off target
 Labels may state
 cut-off temperatures for application
 pesticide to be incorporated into the
soil

26. Degradation: Microbial
 Important means for
destroying pesticide in
soils
 Some soil
microorganisms use
pesticides as food
 bacteria and fungi

27. Soil conditions that favor
Microbial Degradation
- warm soil temperatures
- adequate soil moisture
- favorable pH
- aeration
- fertility
- adsorption

28. Degradation: Chemical
 Non-living processes
 Hydrolysis: a chemical
reaction with water,
typically with a high pH
(alkaline)
 Soil properties and
conditions affect the rate
and type of chemical
reactions
Hydrolysis
occurs
with
High pH

29. Photodegradation
 Breakdown of pesticide
by sunlight
 May be reduced by soil
incorporation

30. Scheme for stages of photochemical degradation
Navarro et al., 2007

31. Common biochemical transformations in water-soil
ecosystems
Navarro et al., 2007

32. EFFECT ON AIR- Pesticide Pollution
• Pesticides can contribute to
air pollution.
• Pesticide drift occurs when
pesticides suspended in the
air as particles are carried
by wind to other areas.
• Weather conditions at the
time of application as well as
temperature and relative
humidity change the spread
of the pesticide in the air.

33. • Low relative
humidity and high
temperature result
in more spray
evaporating.
• The polluted air is
inhaled by humans
end with up with
different diseases.

34. Pesticide Movement
 By air
• Vapor, particle, spray drift
 By water
• Surface runoff
• Movement through soil
 By other objects
• Residues on plants and animals

35. Kerala’s Endosulfan Tragedy
• The UNO classifies
Endosulfan as highly
dangerous insect killer
and banned in 62
countries.
• Endosulfan, a highly
toxic organochlorine
pesticide was sprayed
in the cashew
plantations in
Kasaragod District
sine 1976, till 2001
regularly three times
every year.

36. • The aerial spraying of
Endosulfan was allegedly
undertaken to contain the
menace of the tea
mosquito bug.
• By 1990s health disorders
of very serious nature
among the human
population came to the
lime light.
• Children were found to be
the worst affected with
congenital anomalies,
mental retardation,
physical deformities,
cerebral palsy, epilepsy
etc

37. Bhopal Gas Tragedy
• Bhopal’s pesticide plant was built in 1969 to manufacture Sevin- Asia
to kill beetles, weevils and worms
• The plant was operated by Union Carbide India, Limited, but an
American company, Union Carbide Corporation, held > ½ of 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

38. 27

39. Health hazard
• Direct effect
• Dermal (skin)
• Oral (mouth)
• Inhalation
(lungs)
• Eyes
•Indirect effect
•Air
•Water
•Food chain
•Ingestion

40. • Parts of the body absorb
pesticides at different
rates.
• The head is 4 times more
absorbent than the hand
• Genital area is 11 times
more absorbent.

41. PESTICIDES ENTERING HUMAN BODY
• Pesticides can enter the body
through inhalation of aerosols, dust
and vapour that contain pesticides;
• Enters through,
• oral exposure by consuming
food/water
• skin exposure by direct contact
• The effects of pesticides on human
health depend on
• toxicity of the chemical
• length & magnitude of exposure.

42. Health effect on people with direct
exposure
• Person who are most affected are the persons who are
involved in actual application
Farm sprayers
Farm workers
• These are the most common health effects.
Cancers
Depressions/neurological deficits
Diabetes
Respiratory diseases
Women specific disorders
General health/multiples diseases

43. • Simple irritation of the skin
and eyes.
• Affects the nervous system,
mimicking hormones causing
reproductive problems, and
also causing cancer.
• Children are more
susceptible and sensitive to
pesticides- weaker immune
system
Adverse health effects

44. Acute Toxicity
• immediate harm caused by pesticide exposure
(within 24 hours)
• signal words measure acute toxicity for skin,
mouth, lung and eye exposure
Chronic Toxicity
• delayed - time lapse between exposure and effects (don’t
appear immediately)
• result of repeated exposure to same pesticide or one
with similar mode of action from a single exposure
• effects are not seen until much later

45. Symptoms of OP and Carbamate
poisoning
• Mild - headache, fatigue,
dizziness
• Moderate - muscle
twitching, unable to walk,
pinpoint pupils
• Severe - unconscious,
seizures, death

46. Cholinesterase Test Program
• Consult your doctor.
• Off season base line
test (January or
February)
• Periodic testing during
the season
• Monitor changes in
chlolinesterase levels

47. First Aid
• Act immediately
• Stop exposure
• Rinse with clean water
• Read and follow label directions
• See a doctor and bring the pesticide label

49. Explained the environmental problems associated with
indiscriminate use of pesticides
• “Silent Spring” published in 1962
• Chemical and pesticide industry alarmed bsuccess
• “Most influential book” on environmental movement21
Ecological effects of pesticides

50. 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
• 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

51. Effect of pesticide on environment
 Once a pesticides is released into the environment it
has effects on two broad areas i.e effect on
target organism e.g. insect pest, weeds etc.
non-target organisms e.g. earthworms, pollinators,
humans etc.
 On the target organism also their can be,
 Resistance to pesticide
 Resurgence of pest
 Gene mutation
 Increase in no. of generations
 Change in population growth rate

52. Resurgence
 Rapid reappearance of a pest population in injurious
numbers following pesticide application.
 Persistence & broad spectrum pesticides which kill
even beneficial & natural enemies- resurgence
 Other factor leading to resurgence include:
 Increase in feeding and reproductive rates of insect pests.
 Application of sub-lethal doses of pesticides.
 Elimination of a primary pest.
 Some of the pests which have resurged include cotton
bollworm Helicoverpa armigera

53. Resistance
 Heritable change in the sensitivity of a pest population that
is reflected in the repeated failure of a product to achieve
the expected level of control when used according to the label
recommendation for that pest species.
 Resistant pop continue to multiply till they become dominant
proportion of pop.

54. • Genetic resistance to pesticides.
• Weeds and plant-disease organisms also become
resistant.
• Genetic resistance to pesticides
• 520 insect and mite species
• 273 weed species
• 150 plant diseases
• 10 rodent species (mostly rats)
• At least 17 insect pest species are resistant to
all major classes of insecticides
Superbugs

55. Residues of Pesticides
• Residues in human blood
– Organochlro insecticides found in samples of blood serum in
rural areas of Ahmedabad showed an average of 200.3ppb
– Among all HCH and DDT were chief contaminents
• Residues in human milk
– Potential risk to infants
– Toxilogical implecation cannot be assessed presicely
– Hexachlorobenzens a fungiside is found in human milk and fat
• Residues in food commodities and average daily intake
– Concentration of pesticides varies greatly
– DDT and HCH are found in ground nut and sesamum oils in
Tamil Nadu
• Residues in environmental samples
– Residues in aerosols in ahmedabad ranges from 2.06-
18.96ng/m3 of BHC and DDT
– DDT and HCH in drinking water samples 47.4-256.9ng/L

56. Formation of New Pests
• Turning of minor pest into major pests.
• The natural predators, parasites, & competitors of a
pest may be killed by a pesticide it allows the pest
population to rebound.
• EX. DDT to control insect pests on lemon trees caused
an outbreak of a scale insect that was not a problem
earlier.

57. Effect of pesticides on non-targets
 World wide point of discussion.
The reduction of natural enemies & pollinators in
the recent years.
 Led to a surge in pest levels & use of more
pesticides to control the pest wrecking havoc.
 Pesticides affect both invertebrates
(earthworms) & vertebrates (humans).

58. Effect of Organochlorines on non target organisms

59. Continued….
Jayaraj et al., 2016

60. Effect of pesticides on earthworms
 Earthworms represents >80% of the terrestrial
invertebrates- decomposing soil organic matter in humus.
 Studies have shown pesticide application lead to their
decline.
 Carbamate insecticides are very toxic to earthworms
 Organophosphates -reduce earthworm populations.

61. Pesticides affects,
 Earthworm growth
 Reproduction
 cocoon production
 hatchling per cocoon
 incubation period
 Neurotoxicity
 Physiological damage i.e cellular disfunction &
protein catabolism
 Earthworm general mortality to pesticide
exposure
2
5

62. Effect of pesticides on pollinators
 Pesticides application affect
their activities,
 Foraging behavior
 Colony mortality
 Pollen collecting efficiency
 Application of neonicotinoid
insecticides such as imidacloprids
leads to the above effects on
pollinators
.

63. Effect of pesticides
on natural enemies
• Predators- crucial role in keeping pest
populations under control.
• These include coccinellids, braconid
wasps and predatory spiders.
• E.g. cypermethrin and imidacloprid when
compared to bio-pesticides are used such
neem.
2
8

64. Effect of pesticides on fish
• Important part of marine ecosystem-interact with
physical, biological & chemical environment.
• Provide food source for other animals such as sea
birds and marine mammals - integral part of the
marine food web.
• Pesticides have been directly linked to causing fish
mortality worldwide.

65. Effects of pesticides on birds
 Play a very critical role in
food chains & webs
 Pesticides exposure cause
birds mortality, by
 Ingestion of pesticide
granules, treated seeds &
crops
 Exposure to sprays,
contaminated water
 Feeding on contaminated
prey, and bait
 Decline of populations
 feeding behavior
 reproduction.
 Cabamates, OP, OC

66. Effect of pesticide on amphibians
 The global decline in the amphibian population has
become an environmental concern worldwide.
 Many amphibian species are on the brink of extinction
 7.4% - critically endangered
 43.2% experiencing some sort of population decrease.
 Glyphosate has far reaching effects on non-target
amphibians juvenile frog.

67. Pacific tree frog Effects of pesticides on Pacific tree
frog in the Sierra Nevada
Sparling et al., 2014

68. Pesticides and biomagnification
 Biomagnification is the increase of
some of the pesticides due to its
persistent and non-biodegradable
nature in the tissue of organ at
each successive level of food chain.
 Organisms at the higher levels of
food chain experience greater
harm as compared to those at lower
levels.
 Eg; out of 36 species collected
from three lakes of
northeastern Louisiana (USA)
that were found to contain
residues of 13 organochlorines.

69. Fear of toxicity is better than fear of hunger
Conclusion
Thank you…..