Pesticides AND THEIR USE IN FORENSIC SCIENCE

1. PESTICIDES AND THEIR USE IN
FORENSIC SCIENCE
DR. APJ ABDUL KALAM INSTITUTE OF FORENSIC SCIENCE AND
CRIMINOLOGY, BUNDELKHAND UNIVERSITY JHANSI, U.P
SBUMITTE TO : TANURUP DAS
SUBMITTE BY : KRITIKA SINGH

2. WHAT ARE PESTICIDES?
• Any substance or mixture of substances intended for preventing, destroying or controlling any pest,
including vectors of human or animal disease, unwanted species of plants or animals, causing
harm during or otherwise interfering with the production, processing, storage, transport, or
marketing of food, agricultural commodities, wood and wood products or animal feedstuffs, or
substances that may be administered to animals for the control of insects, arachnids, or other
pests in or on their bodies.
• Pesticides are chemical substances that are meant to kill pests.
• In general, a pesticide is a chemical or a biological agent such as a virus, bacterium,
antimicrobial, or disinfectant that deters, incapacitates, kills, pests.
• This use of pesticides is so common that the term pesticide is often treated as synonymous with
PLANT PROTECTION PRODUCT.
• It is commonly used to eliminate or control a variety of agricultural pests that can damage crops
and livestock and reduce farm productivity.
• The most commonly applied pesticides are insecticides to kill insects, herbicides to kill weeds,
rodenticides to kill rodents, and fungicides to control fungi, mould, and mildew.

3. Pesticides Being Characterized By The Type Of
Organisms They Manage
NARROW-SPECTRUM PESTICIDES
• Pesticides that have a small
coverage range
• They are designed to kill or
manage a select group of
organisms
• Many narrow-spectrum
pesticides are designed to
interact with a characteristic of
the pest that is specific to that
organism, such as a pheromone,
hormone or physical feature.
• Eg:- chitin or inhibitors
BROAD-SPECTRUM PESTICIDES
• Pesticides that are designed to kill
or manage a wide variety of
organisms.
• They are used when many different
species of organisms are causing
harm or when the specific organism
causing harm is unknown.
• Designed to target a system that is
common in many organisms, such
as the nervous system or muscular
system.
• Eg:- methyl bromide
SYSTEMIC PESTICEDES
• systemic pesticides
are taken up by the
plant and transported to
all the tissues (leaves,
flowers, roots and
stems, as well as pollen
and nectar).
• Eg:- Neonicotinoids and
Fipronil (neonics), which
are a class of neuro-
active

4. PESTICIDES CLASSIFIED ON THE BASIS HOW
BIODEGRADABLE THEY ARE:
Biodegradable:
• The biodegradable kind is those which can be broken down by microbes and other living
beings into harmless compounds.
• Eg:- The soil fumigant methyl bromide the herbicides dalapon, and the fungicide
chloroneb.
Persistent:
• While the persistent ones are those which may take months or years to break down.
• Examples:-
• Hexachlorocyclohexane (lindane)
• DDT and related compounds DDE and DDD.
• Cyclodienes (aldrin, heptachlor, and others)
• Mirex and chlordecone.

5. GROUPED BY TYPES OF PESTS THEY KILL
Type Action
Algicides Control algae in lakes, canals, swimming pools, water tanks, and other sites
Antifouling agents Kill or repel organisms that attach to underwater surfaces, such as boat bottoms
Antimicrobials Kill microorganisms (such as bacteria and viruses)
Attractants
Attract pests (for example, to lure an insect or rodent to a trap). (However, food is
not considered a pesticide when used as an attractant.)
Biopesticides
Biopesticides are certain types of pesticides derived from such natural materials as
animals, plants, bacteria, and certain minerals
Biocides Kill microorganisms
Disinfectants and sanitizers Kill or inactivate disease-producing microorganisms on inanimate objects
Fungicides Kill fungi (including blights, mildews, molds, and rusts)
Fumigants Produce gas or vapor intended to destroy pests in buildings or soil
Herbicides Kill weeds and other plants that grow where they are not wanted
Pheromones Biochemical used to disrupt the mating behavior of insects
Repellents Repel pests, including insects (such as mosquitoes) and birds
Rodenticides Control mice and other rodents
Slimicides Kill slime-producing microorganisms such as algae, bacteria, fungi, and slime molds

6. TYPE ACTION
Insecticides Kill insects and other arthropods
Miticides Kill mites that feed on plants and animals
Microbial pesticides Microorganisms that kill, inhibit, or out compete pests, including insects or other microorganisms
Molluscicides Kill snails and slugs
Nematicides Kill nematodes (microscopic, worm-like organisms that feed on plant roots)
Ovicides Kill eggs of insects and mites
The term pesticide also include these substances:
• Defoliants : Cause leaves or other foliage to drop from a plant, usually to facilitate harvest.
• Desiccants : Promote drying of living tissues, such as unwanted plant tops.
• Insect growth regulators : Disrupt the molting, maturity from pupal stage to adult, or other life
processes . of insects.
• Plant growth regulators : Substances (excluding fertilizers or other plant nutrients) that alter the .
. expected growth, flowering, or reproduction rate of plants.
• Soil sterilant : a chemical that temporarily or permanently prevents the growth of all plants and
animals, . depending on the chemical. Soil sterilants must be registered as pesticides
• Wood preservatives : They are used to make wood resistant to insects, fungus, and other pests.

7. CHEMICALLY-RELATED PESTICIDES
Organophosphate:
• Most organophosphates are insecticides, they affect the nervous system by disrupting the enzyme that
regulates a neurotransmitter.
Carbamate:
• Similar to the organophosphorus pesticides, the carbamate pesticides also affect the nervous system by
disrupting an enzyme that regulates the neurotransmitter. However, the enzyme effects are usually reversible.
Organochlorine insecticides:
• They were commonly used earlier, but now many countries have been removed Organochlorine insecticides
from their market due to their health and environmental effects and their persistence (e.g., DDT, chlordane,
and toxaphene).
Pyrethroid:
• These are a synthetic version of pyrethrin, a naturally occurring pesticide, found in chrysanthemums(Flower).
They were developed in such a way as to maximise their stability in the environment.
Sulfonylurea herbicides:
• The sulfonylureas herbicides have been commercialized for weed control such as pyrithiobac-sodium,
cyclosulfamuron, bispyribac-sodium, terbacil, sulfometuron-methyl Sulfosulfuron, rimsulfuron,
pyrazosulfuron-ethyl, imazosulfuron, nicosulfuron, oxasulfuron, nicosulfuron, flazasulfuron, primisulfuron-
methyl, halosulfuron-methyl, flupyrsulfuron-methyl-sodium, ethoxysulfuron, chlorimuron-ethyl, bensulfuron-
methyl, azimsulfuron, and amidosulfuron.
Biopesticides:
• The biopesticides are certain types of pesticides derived from such natural materials as animals, plants,
bacteria, and certain minerals.

8. THE FOLLOWING IS A LIST OF 24 PESTICIDES REGISTERED AND USED IN
INDIA, CLASSIFIED AS POTENTIAL CARCINOGENS BY THE US EPA:
• Acephate (C)
• Alachlor (B2)
• Atrazine (C)
• Benomyl (C)
• Bifenthrin (C)
• Captan (B2)
• Chlorothalonil (B2)
• Cypermethrin (C)
• Diclofop-Methyl (C)
• Dicofol (C)
• Mancozeb (B2)
• Methomyl (C)
• Metolachlor (C)
• Oxadiazon (C)
• Oxyflourfen (C)
• Permethrin (C)
• Phosphamidon (C)
• Propiconazole (C)
• Propoxur (B2)
• Thiodicarb (C)
• Thiophanate Methyl (C)
• Triadimefon (C)
• Trifluralin (C).
• Dichlorvos (C)

9. PESTICIDE TOXICITY
• Some pesticides are dangerous after one large dose (acute toxicity). Others can be dangerous after
small, repeated doses (chronic toxicity). Measuring Acute Toxicity (LD50And LC50 Values) Acute
toxicity of a pesticide refers to the effects from a single dose or repeated exposure over a short time (e.g.
one day), such as an accident during mixing or applying pesticides. Acute toxicity is measured by LD50
and LC50 values.
• The LD50 value is the amount of pesticide (lethal dose) which kills 50% of the test animals. These
treatments are through the skin (dermal) or through the mouth (oral).
• The smaller the LD50, the more toxic the pesticide. Example: a pesticide with an LD50 of 5 mg/kg is
100 times more toxic than a pesticide with an LD50 of 500 mg/kg 2.
• These values are given in milligrams per kilogram of body weight of the animal (mg/kg body wt.). A
pesticide with a lower LD50 is more toxic than a pesticide with a higher number because it takes less of
the pesticide to kill half of the test animals.

10. Relation of oral LD50 to approximate lethal dose in adult humans.
• Note that a child who is one-fifth the weight of an adult would require only one-fifth the amount of
pesticide to suffer the same toxic effects as the adult.
Important characteristics to note about LD50 and LC50 values:
They Are Based On A Single Dose (LD50) Or Short Exposure (LC50)
They Do Not Indicate Cumulative Effects Of Small Doses;
They Are An Indicator Of The Amount Of Chemical Required To Kill Or Severely Injure Animals, And Do
Not Indicate The Amount Of Chemical Causing Less Severe Toxic Effects.
Oral LD50 Approximate lethal dose to average size adult (70 kg
or 155 lb.)
Less than 50mg/kg 0.3-3ml [few drops of ½ teaspoon]
50 to 500 mg/kg 3 mL to 30 mL (half a teaspoon to two tablespoons)
500 to 5,000 mg/kg 30 mL to 300 mL (1 to 10 fluid ounces)
5,000 to 15,000
mg/kg
300 mL to 900 mL (10 to 30 fluid ounces)

11. Benefits of Pesticides
• The major advantage of pesticides is that
they can save farmers. By protecting
crops from insects and other pests.
However, below are some other primary
benefits of it.
• Controlling pests and plant disease
vectors.
• Controlling human/livestock disease
vectors and nuisance organisms.
• Controlling organisms that harm other
human activities and structures.
• 8
Effects of Pesticides
• The toxic chemicals in these are designed to deliberately
released into the environment.
• Though each pesticide is meant to kill a certain pest, a very
large percentage of pesticides reach a destination other than
their target. Instead, they enter the air, water, sediments, and
even end up in our food.
• Pesticides have been linked with human health hazards, from
short-term impacts such as headaches and nausea to chronic
impacts like cancer, reproductive harm.
• The use of these also decreases the general biodiversity in the
soil. If there are no chemicals in the soil there is higher soil
quality, and this allows for higher water retention, which is
necessary for plants to grow.
BENEFITS AND EFFECTS OF PESTICIDES