Growing demand for food has led to increased use of pesticides and fertilizers, contaminating the environment including water bodies. Widespread pesticide contamination has been reported in aquatic ecosystems. It is important to study pesticide pollution and find safe use and control methods. Pesticides can enter the body through various routes like dermal absorption, ingestion, inhalation and eyes and cause harm. Their presence in water depends on factors like runoff, spray drift, and industrial effluents. Pesticides can accumulate in tissues of aquatic plants and animals and biomagnify in the food chain. Effects of pesticides on fish include morphological changes, behavioral changes, and impacts on reproduction.

1. PESTICIDES AND HERBICIDES
PRESENTED BY- SAKSHI PATIL
AEM-MA-09-06

2.  Growing demand for food as a result of increasing population has led to a
substantial increse in the production of agro-chemicals like pesticides and
fertilizers, resulting in a continued contamination of our environment including
water bodies.
 Widespread contaminations of the environment by pesticides has been
reported and sooner or later a large fraction of these contaminants find their
way into various aquatic ecosystem.
 Therefore it is important to study the problem of pesticide pollution and to
find ways and means for the safe use and control of pesticides.

3. Pesticide
 Any material that is used to kill a pest is pesticide.
 Pests are destructive organisms (insects, bacteria) that affect crops, food,
livestock, health, etc.
 Pest is any organism that compete for food or living space .
 Cide -Latin word "to kill."
 According to the law, a pesticide is any substance "intended for preventing,
destroying, repelling, or mitigating any pest."

4. Classification of pesticides
Method of classification Examples
By target insecticides, herbicides, fungicides, rodenticides, algicides,
nematociddes
By chemical nature natural organic compound ,inorganic compunds, chlorinated
hdrocarbons, organophosphate, carbamates
By physical state dusts, dissolve solutions, suspended solutions, volatile solids
By mode of action contact poisons, fumignats, stomach poisons

5. Insectides
 Those compounds that are effective against insects.
 Most of the insectides are applied as a spray, others are applied
as a dust, aerosol.
 The majority of insecticides used today are synthetic organic
chemical and most of them are nerve poisons.
 They act by inhibiting the organisms enzymes or interacting with
other target sites vital to the porper functioning of the insects's
nervous system.

6.  They are also called organochlorides, were the first commercial
organic insecticide to be developed. eg: DDT, dieldrin, Aldrin,
endrin etc.
(Dichloro-diphenyl-trichloroethane)
 It is applied to a variety of agriculture crops, providing enormous
success in pest control.
 It is also used to control dieases carrying insects such as
moisquitoes that spread malaria.

7.  When DDT 's environmental consequences became evident, its
use was either limited or totally banned in industrialized countries.
 It has a very low vapour pressure
 It is extremely low solubility in water
 High solubility in oils

8.  DDT can be readily absorbed through the skin in the fatty tissues
of living organisms and can biomagnify the tissue as pass through
the food chain.

9. Effects
 It blocks normal nervous
system of fish eating
birds.(eagles, Ospreys,
Pelicans etc…)
 Interferes with calcium
deposition during the formation
of egg shell in marine birds .

10.  They are most toxic among insecticide.
 They are dangerous not only to insects but also to mammals.
 Examples: parathion, malathion, timet etc.
 Symptoms of poisoing by organophospahte insecticides in
humans include vomiting, cramps, sweating, blurred vision,
severe cases may fatal with respiratory failure.

11.  Organophospahte are more toxic than chlorinated hydrocarbons
as they are more easily biodegraded than the organochlorines.
 Organophosphate do not persist in the environment or
accumulate in fatty tissue.
The mode of action of this group is the inhibition of AChE
(acetylicholinesterase).

12.  These are derivatives of carbamic acid, HO-CO-NH2
 It is widley used for worm control on vegetables.
 Example: aldicarb (trade name:temik) .
 Mode of action is same as that of organophosphates.i.e,
inhibition of AChE.

15.  It is used for kill or inhibit the growth of unwanted plants.
 Example : 2,4-D, Diquat, Chlorophenoxy, Acetanilides etc.
 Numerous clinical reports on humans have dsecribed peripheral
neuropathy (degeneration of nervous tissue) and acute myopathy
( disorder of muscle tissue or muscles).
 Clinical symptoms of severly poisoned farmer include pain ,
twitching, mucsle spasms.

16.  Fungicides are pesticides that kill or prevent the growth of fungi
and their spores.
 They can be used to control fungi that damage plants.
 Fungicides bind with specific enzymes to interrupt the metabolic
pathways involved with cellular respiration.
 Example : Thiocarbamates, Cupric salts, Triazoles etc.

17.  Rodenticides are pesticides that kill rodents.
 Rodents include not only rats and mice, but also squirrels, rat,
woodchucks.
 They can damage crops, transmit disease, and in some cases
cause ecological damage.
 Example : Warfarin, Chlorphacinone, Diphacinone etc.

18. Pesticide cycle

19. Exposure route

21.  Dermal absorption may occur as a result of splashes and spills when
handling (mixing, loading or disposing) pesticides.
 Pesticides can cross the epithelium of the skin .
 Skin absorption is higher when there is vasodilatation.
 Powders, dusts, and granular (dry) pesticides are not absorbed so easily
through the skin than the liquid formulations.

22. The seriousness of dermal exposure depends upon:
 The dermal toxicity of the pesticide,
 The rate of absorption through the skin,
 The size of the skin area contaminated,
 The length of time the material is in contact with the skin,
 The amount and concentration of pesticide on the skin.

23.  Pesticides entering the body through the mouth may cause serious illness,
severe injury, or sometimes even death.
 These products may be consumed accidentally or may be consumed
intentionally by individuals who intend on personal harm (deliberate self-
poisoning).
 Oral exposure can also occur when hands are not properly washed before
eating. Furthermore, pesticides may be swallowed by mistake.
 Materials that are ingested can be absorbed along the gastrointestinal tract,
with the small intestine being reported to be the major absorption site. Once
absorbed, they find their way into the blood stream, through which they are
capable of readily distributing throughout the entire body.

24.  Pesticides entering the body through inhalation can cause serious damage
to the nose, the throat, and the lung tissues.
 The rapid absorption of pesticides through this specific route increases the
risk of respiratory exposure. The greatest potential for poisoning via
respiratory exposure is with vapours and extremely fine particles of the spray
solution.
 Pesticide exposure is usually low when dilute sprays are applied with
common conventional spraying equipment because larger droplet sizes are
produced. By contrast, when low volume equipment is utilized to apply
concentrated material, the potential for an event of respiratory exposure is
increased because smaller droplets are produced.
 Respirators and gas masks can provide protection from respiratory

25.  The tissues of the eye are extremely absorbent. Blood vessels are very
close to the surface of the eye, so pesticides can be easily absorbed into the
bloodstream.
 Under certain conditions and using certain pesticides, absorption through the
eyes can be significant and particularly hazardous.
 Some products are corrosive and can cause severe eye damage or even
blindness. Serious eye exposure can result from airborne dusts particles,
spray mists, or from rubbing the eyes with contaminated hands, clothing,
such as unwashed gloves.
 Therefore, protective goggles should be used whenever there is a possibility
of pesticides coming into contact with the eyes.

26. Sources of pesticides in water
 Run off from agricultural field
 Spray drift
 Rain water
 Industrial effluents
 Direct application of pesticides to water

27.  Most of the survey and data generally refers to organochloride insectides in
river.
 DDT residues were most common and often accounted for the largest
amount.
 The overall amount of organochloride residues genearlly do not extend
beyond one part per billion and such levels normally do not result in any
acute toxicity to fish and most other aquatic organism.
 Generally the pesticides level in the lakes seem to depend upon the size of
the lake and also if the sewage or industrial effluents are discharge into
them.The higher level of pesticides due to their being surrounded by
industrial complexes.

28.  The persistence of pesticides will depend very much on their
chemical stability. The stability ranges from very short periods to
several years.
 The solubility of the pesticides in water will also effect their
persistance. The solubilities of pesticide vary greatly. They are
easily diluted and are less persistent.
 On the other hand relatively insoluble chemicals like DDT are not
leached easily and become fractions of the bottom sediment and
settle at the bottom.

29.  The pesticide present in the water get concentrated in the tissue
of plants and animals. The extent of this accumulation gives an
indication of the pesticides transport in food chain and also the
potential hazards in the environment.
 Bioaccumulation depends upon several factors like the lipid/
water partition coefficient environmental conditions and nature of
aquatic micorganism.
 Some pesticides can be metabolized and degrade by the biota.

30.  It is possible to decrease water contamination.
 Less persistent pesticides may be used in placed of highly.
 Alternate methods of pest control lilk biological control, attractants
etc. may be used.
 The industrial effluents containing pesticides can be treated
before release into the rivers in various way which will remove
almost all of residues. The treatment involves coagulation,
sedimentation, filtration it can remove upto 90% DDT.

31. 1. Organochlorines
 OC compounds are more toxic than organophosphate compounds to fish.
Among OC endrin and other cycloidienes (endosulphan) are highly toxic to fish
 Among OC compounds cyclodienes have high acute toxicity, whereas DDT
has a greater chronic toxicity.
2. Organophosphates, carbamtes and pyrethroids
 OPs have negligible chronic toxicity, but some of them have moderate to high
acute toxicity.
 The chronic toxicity of OP and carbamate compound is low.

32. 3. Herbicides
 Few of herbicides have chronic toxicity.
 The acute toxicity of herbicides are also low.
 The major problem arising from the application of herbicides for
the control of aquatic weed is not direct but results from the
depletion of DO owing to the decomposition of the dead and
decaying weeds.
 Problem with herbicides is the very high quantities that have to be
initially used for effective weed control.

33. 1. Morphological changes
 Darkening of the skin
 Formation of brown spot on head
 Swelling of th eyes
 Erosion of the fin margin
 Wies reported relationship between acetylcholinesterase( AChe)
inhibition and retardation of the fin regeneration.

34. 2. Vertebral damage and anatomical changes
 Induce vertebral damage and skeletal deformities.
 Darsie and coriden reported that ocellated malathion exposed
killifish developed a laterally bent caudal peduncle and bent body.
 McCann and jasper reported extensive hemorrhaging of the
vertebral region.
 Uncoordinated movement, scoliosis ( lateral curvature of spine)
 It was suggested tha AChe was responsible for this abnormality.

35. 3. General behaviour changes
 A marked declining in the frequency of various agonostic
behaviour ( chasing, vacating, nipping) etc. was noticed.
 Comfort behaviors like flicks, thrusts, coughs, etc. increased with
increasing concentration of toxicant .
 At higher concentartion some individuals were unable to maintain
position and were swept down stream.

36. 4. Swimming and hypersensitivity
 Aberrant swimming
 Unusual response to electric field
 Erractic swimming and slugish feeding
 Loss in equilibrium

37. 5. Schooling behaviour
 Disruption of schooling behaviour due to sublethal stress of
toxicants, results in increased swimming activity and entails
increased expenditure of energy and hence higher food
requirement.

38. 6. Learning ability
 Increase in amplitude and decrease the of spontaneous cerebral
activity.
7. Effect on respiration
 Exposure to sublethal concentration is reported to increased
respiratory activity, resulting in increased ventilation and hence,
inctease uptake of toxicant.

39. 8. Effect on feeding
 Reduced feeding and decreased ability to preceive the presence
of food were evident.
 More time required to consume certain quantity of food.
 In absence of contaminants, food odor was attarctive but when
the food is contaminated with toxicant, the fish avoided it.

40. 9. Effect on reproduction and fecundity
 Caused delay in the spawning
 Fertility of female was reduced
 Fecundity reduced
 Lower GSI

41.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5606636/
 https://www.who.int/ceh/capacity/Pesticides.pdf
 http://npic.orst.edu/ingred/ptype/index.html
 https://www.who.int/ceh/capacity/Pesticides.pdf
 Yu.M.H., 2001,Environmental toxicology,187-208
 Eastern.W.,1983,Water pollution and mangement, 51-73
 Murty.A.S., 2001,Toxicity of pesticides to fish, volume (II)