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PESTICIDES AND INSECTICIDES Presented By: dr.SaharSiddiq 1


PESTICIDE A pesticide is any substance or mixture of substances intended for preventing, destroying, repelling, or mitigating any pest . PEST: Any organism that damages crops, injures or irritates livestock or man, or reduces the fertility of land . Pesticide derived from Latin words pestis means plague, cide means to kill . 2


INSECTICIDE It is a sub class of pesticides. A substance used to kill or destroy insects. INSECT: Any small air-breathing arthropod of the class Insecta , having a body divided into head, thorax, and abdomen, three pairs of legs, and (in most species) two pairs of wings. Insecticide derived from Latin insectum means (animal that has been) cut into sections and cide . 3

How Are Pesticides Used?:

How Are Pesticides Used? Pesticides are used both at home and in private gardens as well as by most farmers who, under pressure to provide food at low prices often rely on pesticides to maximize their harvest. The use of pesticides in farming often relies on the fact that levels used to kill insects are generally low enough not to affect humans . 4

History Of Pesticides:

History Of Pesticides Before 2000 BC 4,500 Years ago Elemental Sulfur Dusting 4,000 years old use of poisonous plants for pest control is also mentioned in history. 15 th Century Arsenic, Mercury, Lead 17 th Century Nicotine sulfate 19 th Century Pyrethrum and Rotenone 1950’s Arsenic based insecticides 5

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Organochlorines such as DDT Organophosphates and Carbamates in 1975 Pyrethrin , a dominant insecticide now a days. 6

Ideal Properties Of Pesticides:

Ideal Properties Of Pesticides Effective against pests Stability Toxicity Affordable Non-cumulative (No biomagnification ) Effects (Acute and Chronic) 7

Classification Of Pesticides:

Classification Of Pesticides Pesticides can be classified on basis of: T arget organisms C hemical structure P hysical state Biological mechanism But the most popular and preferable classification of pesticides is based on Target Organisms. 8

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Type of Pesticide Target Pests Group Algicide Algae Avicide Birds Bactericide Bacteria Fungicide Fungi Herbicide Herbs and Weeds Insecticide Insects Miticide/Acaricide Mites Molluscicide Snails Nematicide Nematodes Rodenticide Rodents Virucide Viruses 9

Insecticides Classification:

Insecticides Classification Insecticides are primarily grouped into chemical families. Organochlorines : The organic hydrocarbon molecule containing chlorine atoms. They operate by disrupting the sodium/potassium balance of the nerve fiber, forcing the nerve to transmit continuously . E.g DDT ( D ichloro D iphenyl T richloroethane ), Aldrin , Dieldrin . 10

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Organophosphates and Carbamates have largely replaced organochlorines . They operate through inhibiting the enzyme A cetyl C holin E sterase (ACE), allowing acetylcholine to transfer nerve impulses indefinitely and causing a variety of symptoms such as weakness or paralysis . Carbamates are organic compounds derived from carbamic acid (NH 2 COOH ). 11

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Organophosphate is the general name for esters of phosphoric acid. Examples include Parathion and Malathion . Due to their mechanism of action, they had been used in WWII as nerve agents . Organophosphates are quite toxic to vertebrates, and in some cases have been replaced by less toxic carbamates , e.g Carbaryl and Aldicarb . 12

Impacts Of Use:

Impacts Of Use On Environment: Pesticide use raises a number of environmental concerns. Over 98% of sprayed insecticides and pesticides reach a destination other than their target species, including non-target species, air, water and soil. Pesticide drift occurs when pesticides suspended in the air as particles are carried by wind to other areas, potentially contaminating them. 13

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Pesticides are one of the major causes of: W ater pollution P ersistent organic pollutants thus contributing to soil contamination. Reduces biodiversity R educes nitrogen fixation P ollinator decline D estroys habitat especially for birds T hreatens endangered species Pesticide resistance 14

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On Economy: The use of pesticides not only effect the environment but also the economy of the country. The different costs for pesticides include: Developmental costs Testing and evaluation of new product Public health issues and awareness programs Bird and crop losses Groundwater contamination 16

Persistence of Pesticides:

Persistence of Pesticides " Persistent " pesticides are those that do not breakdown in the environment, but remain toxic to fish, animals, and humans for many years. They can bioaccumulate , their toxic effects multiply as they move up the food chain from plants, to animals, and finally human beings. Bioaccumulation refers to the accumulation of substances, such as pesticides, or other organic chemicals in an organism. Bioaccumulation occurs when an organism absorbs a toxic substance at a rate greater than that at which the substance is lost. Thus, the longer the biological half-life of the substance the greater the risk of chronic poisoning, even if environmental levels of the toxin are not very high. 17

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Biomagnification is also called Bioamplification . It is simply the increase in concentration of a substance in a food chain, not an organism. Persistent organic pollutants (POPs) are compounds that biomagnify , for example DDT . 18

Public Health Considerations:

Public Health Considerations Pesticides must be labeled. The “ label ” includes the actual label on the container and literature that comes with the pesticide. Employees dealing with pesticides at any level have a legal right to know what chemicals they may be exposed to and to review the “label” or Material Safety Data Sheets for those chemicals. So a Pesticide Label is a Legal Document . 19

Material Safety Data Sheets(MSDS):

Material Safety Data Sheets(MSDS) MSDS give the user information needed to use the chemical safely, including: Manufacturer contact information Components, contaminants, and exposure limits Fire and explosion data Toxicity data Health hazards Effects of exposure Emergency and first aid Appropriate protective equipment 20

Effects Of Pesticides On Human Beings:

Effects Of Pesticides On Human Beings The wide variety of pesticides in common use means they will affect a broad cross section of people differently. The amount of common pesticides used on the fruits and vegetables commonly consumed are supposed to be within government standards , but often the people who harvest and consume them hardly get food completely free of such chemicals . Common pesticide side effects include: endocrine system failure, infertility, 21

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birth defects, cancer, and a number of "mutagenic" effects, which science has yet to fully understand. Long term affects of pesticide exposure can lead to: birth defects fetal complications in women of childbearing age as well. 22

Types Of Exposure To Pesticides:

Types Of Exposure To Pesticides Pesticides contact your body in four main ways: Oral exposure (when you swallow a pesticide) Inhalation exposure (when you breathe in a pesticide) Ocular – (through the eyes) Dermal (through the skin) 23

Pesticide Hazards:

Pesticide Hazards 24 Acute exposure Chronic exposure Inhalation Absorption through skin Through food or water How pesticides get in Exposure levels Central nervous system Skin irritation Eye irritation Health effects (depends on specific pesticide) Hormone imbalance Cancer Liver damage Reproductive effects Through eyes

Pesticides In Use In PAKISTAN:

Pesticides In Use In PAKISTAN Hydrocarbon Pesticide: Aldrin , BHC ( lindane ), Chlordane , DDT , Dieldrin , Endrin , Heptachlor , Thiodane . Organophosphate Group: Ethion , Usathion , Arathion , Thimet , Imecron , Formathion , Azodrin , Nexion , Arbicron , Diptrex , Diazinon , Imidan , Lebaycid , Malathion , Methyl Parathion , Metasystox , Phosdrin Sumithion , Nexagan , Disyton / Solvirex . *Reference Link: http :// /chemical-groups/one- list.tcl?short_list_name = brpest *Text in Color Indicates Banned or Severely Restricted Pesticides. 25

Banned And Severely Restricted Pesticides:

Banned And Severely Restricted Pesticides A " banned " pesticide is defined as a pesticide for which all registered uses have been prohibited by final government action or for which all requests for registration or equivalent action for all uses have, for health or environmental reasons, not been granted. A " severely restricted " pesticide is defined as a pesticide for which virtually all registered uses have been prohibited by final government regulatory action, but for which certain specific registered use or uses remain authorized . 26

Important Information:

Important Information Be aware that pesticides can be used intentionally to harm humans, animals and crops. Understand behaviors that may indicate suspicious activity because terrorists might use crop dusters to spray pesticides on large crowds. But pesticides have not been used often in terrorist attacks. Understand that specific security measures can prevent unlawful access to pesticides. But pesticide misuse may also result from unintentional use or release of pesticides. 27

Improving Security to Avoid Intentional Use or Release:

Improving Security to Avoid Intentional Use or Release Storage Transportation Personnel Disposal Response 28

Toxicity And Poisoning With Pesticides:

Toxicity And Poisoning With Pesticides A pesticide poisoning occurs when chemicals intended to control a pest affect non-target organisms such as humans, wildlife, or bees. But our major concern here is the poisoning in human beings. The most common exposure scenarios for pesticide-poisoning cases are: Occupational exposure Accidental or suicidal poisonings The general public who are exposed through environmental contamination. 29

Occupational Exposure Diseases Reported For Pesticides:

Occupational Exposure Diseases Reported For Pesticides Chemicals Organophosphates Halogenated Hydrocarbons ( Organochlorines ) Miscellaneous Types of diseases Systemic poisoning Respiratory Skin Others 30

Accidental And Suicidal Exposure:

Accidental And Suicidal Exposure Self-poisoning with agricultural pesticides represents a major hidden public health problem. It is one of the most common forms of self-injury in Pakistan. The World Health Organization estimates that 300,000 people die from self-harm each year in the Asia-Pacific region alone. Acute pesticide poisoning is a large-scale problem, especially in developing countries. Most cases of intentional pesticide poisoning appear to be impulsive acts undertaken during stressful events , and the availability of pesticides strongly influences the incidence of self poisoning. 31

Common Pesticides And Their Effects On Human Beings:

Common Pesticides And Their Effects On Human Beings Organochlorines : The organochlorine pesticides, like DDT, aldrin , and dieldrin are extremely persistent and accumulate in fatty tissue. Through the process of bioaccumulation , large amounts of organochlorines can accumulate in humans. There is substantial evidence to suggest that DDT, and its metabolite DDE, act as endocrine disruptors , interfering with hormonal function of estrogen, testosterone, and other steroid hormones. 32

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Anticholinesterase compounds (Organophosphates and Carbamates): Certain organophosphates have long been known to cause a delayed-onset toxicity to nerve cells , which is often irreversible . Several studies have shown persistent deficits in cognitive function in workers chronically exposed to pesticides. Newer evidence suggests that these pesticides may cause developmental neurotoxicity at much lower doses and without depression of plasma cholinesterase levels. 33

Prevention/Minimization Of Accidental Or Occupational Exposure:

Prevention/Minimization Of Accidental Or Occupational Exposure Accidental poisonings can be avoided by proper labeling and storage of containers. When handling or applying pesticides, exposure can be significantly reduced by protecting certain parts of the body where the skin shows increased absorption. Using chemical-resistant gloves has been shown to reduce contamination by 33-86% . 34

Management And Treatment In Case Of Acute Poisoning:

Management And Treatment In Case Of Acute Poisoning Specific treatments for acute pesticide poisoning are often dependent on the pesticide or class of pesticide responsible for the poisoning. The basic management techniques that are applicable to most acute poisonings include: skin decontamination airway protection seizure treatment gastrointestinal decontamination ( Lavage is contra-indicated in cases of hydrocarbon ingestion) 35

Exposure Through Environmental Contamination:

Exposure Through Environmental Contamination Estimating the numbers of chronic poisonings worldwide is quite difficult. Rachel Carson's Silent Spring brought about the first major wave of public concern over the chronic effects of pesticides. 36

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