Pesticides

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Pesticides

  1. 1. SCIENCE EXHIBITION EFFECTS OF CHEMICAL PESTICIDES ON ENVIRONMENT
  2. 2. Welcome, Viewers. You areexpected to maintainpatience while viewingthis presentation .Youare requested to shareyour views about this
  3. 3. GROUP MEMBERS1. Kunal Tribhuvan & Abhishek Kamlapure2. Anirudh Mannadiar & Jatin Mhatre3. Nikita Kulkarni & Komal Bhaiya4. Akshay Govekar & Hardik Jakula
  4. 4. IntroductionGreen Revolution brought ChemicalPesticidesFor decades our food and waterhaven contaminated by powerful,harmful pesticides which have beenpromoted as necessary for betteragricultural output. But the reality isthat we don’t need pesticides forbetter yield and their use in not only
  5. 5. • Pesticides can contribute to air pollution. Pesticide drift occurs when pesticides suspended in the air as particles are carried by wind to other areas, potentially contaminating them. Pesticides that are applied to crops can volatilize and may be blown by winds into nearby areas, potentially posing a threat to wildlife.• Weather conditions at the time of application as well as temperature and relative humidity change the spread of the pesticide in the air. As wind velocity increases so does the spray drift and
  6. 6.  Also, droplets of sprayed pesticides or particles from pesticides applied as dusts may travel on the wind to other areas , or pesticides may adhere to particles that blow in the wind, such as dust particles. Ground spraying produces less pesticide drift than aerial spraying does. Farmers can employ a buffer zone around their crop, consisting of empty land or non-crop plants such as evergreen trees to serve as windbreaks and absorb the pesticides, preventing drift into other areas. Such windbreaks are legally required in the Netherlands. Pesticides that are sprayed on to fields and
  7. 7. Impact on water
  8. 8.  There are four major routes through which pesticides reach the water: it may drift outside of the intended area when it is sprayed, it may percolate, or leach, through the soil, it may be carried to the water as runoff, or it may be spilled, for example accidentally or through neglect. They may also be carried to water by eroding soil. Factors that affect a pesticides ability to contaminate water include its water solubility, the distance from an application site to a body of water, weather, soil type, presence of a growing crop, and the method used to apply the chemical.
  9. 9. IMPACT ON SOIL Many of the chemicals used in pesticides are persistent soil contaminants, whose impact may endure for decades and adversely affect soil conservation. The use of pesticides decreases the general biodiversity in the soil. Not using the chemicals results in higher soil quality, with the additional effect that more organic matter in the soil allows for higher water retention. This helps increase yields for farms in drought years, when organic farms have had yields 20-40% higher than their
  10. 10.  Degradation and sorption are both factors which influence the persistence of pesticides in soil. Depending on the chemical nature of the pesticide, such processes control directly the transportation from soil to water, and in turn to air and our food. Breaking down organic substances, degradation, involves interactions among microorganisms in the soil. Sorption affects bioaccumulation of pesticides which are dependant on organic matter in
  11. 11.  Thisis one of the most dangerous pesticides and it was found in some samples of mother’s milk due to consumption of vegetables sprayed with pesticides.
  12. 12. Effect on plants Nitrogen fixation, which is required for the growth of higher plants, is hindered by pesticides in soil. The insecticides DDT, methyl parathion, and especially pentachlorophenol have been shown to interfere with legume- rhizobium chemical signalling. Reduction of this symbiotic chemical signalling results in reduced nitrogen fixation and thus reduced crop yields. Root nodule formation in these plants saves the world economy $10 billion in synthetic nitrogen fertilizer every year.
  13. 13. Application ofpesticides to cropsthat are in bloom cankill honeybees, whichact as pollinators.The USDA and USFWS estimate that USfarmers lose at least$200 million a yearfrom reduced croppollination becausepesticides applied tofields eliminate abouta fifth of honeybeecolonies in the US andharm an additional15%.
  14. 14. Just Look how thispoison is being spreadover miles !
  15. 15. Pest resistance Pests may evolve to become resistant to pesticides. Many pests will initially be very susceptible to pesticides, but some with slight variations in their genetic makeup are resistant and therefore survive to reproduce. Through natural selection, the pests may eventually become very resistant to the pesticide. Pest resistance to a pesticide is commonly managed through pesticide
  16. 16. Pest rebound and secondarypest outbreaksNon-target organisms, organisms that the pesticides are not intended to kill, can be severely impacted by use of the chemicals. In some cases, where a pest insect has some controls from a beneficial predator or parasite, an insecticide application can kill both pest and beneficial populations. A study comparing biological pest control and use of pyrethroid insecticide for
  17. 17. Likewise, pesticides sprayed in an effort to control adult mosquitoes, may temporarily depress mosquito populations, however they may result in a larger population in the long run by damaging the natural controlling factors. This phenomenon, wherein the population of a pest species rebounds to equal or greater numbers than it had before pesticide use, is called pest resurgence and can be linked to elimination of predators and other natural enemies of the pest. Loss of predator species can also lead to a related phenomenon called
  18. 18. An estimated third of the 300 most damaging insects in the US were originally secondary pests and only became a major problem after the use of pesticides. In both pest resurgence and secondary pest outbreaks, the natural enemies have been found to be more susceptible to the pesticides than the pests themselves, in some cases causing the pest population to be higher than it was before the use of pesticide.
  19. 19. Eliminating pesticides Many alternatives are available to reduce the effects pesticides have on the environment. There are a variety of alternative pesticides such as manually removing weeds and pests from plants, applying heat, covering weeds with plastic, and placing traps and lures to catch or move pests. Pests can be prevented by removing pest breeding sites, maintaining healthy soils which breed healthy plants that are resistant to pests, planting native
  20. 20.  There is much debate over alternative methods of controlling pesticides. In many instances, biological controls such as resistant plant varieties and the use of pheromones, have been successful and at times resolving a pest problem permanently. Integrated Pest Management (IPM) has also been one practice in pest management which establishes chemical use on a need basis only. IPM is a more socially accepted practice and causes less harm to the health of humans and the environment. The focus is on the pest culture, life cycle, and role

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