Environmental Effects of Pesticides Essay

Over 98% of sprayed insecticides and 95% of herbicides open a destination former(a) than their target species, including nontarget species, zephyr, pee, bottom sediments, and nutriment.1 Pesticide contaminates land and water when it escapes from production sites and storage tanks, when it runs off from fields, when it is discarded, when it is sprayed aeri solely toldy, and when it is sprayed into water to pop up algae.2 The keep nap of pesticide that migrates from the intended application bea is influenced by the particular chemical substances properties its appositeness for binding to smear, its vapor pressure, its water solubility, and its resistance to being broken down all over time.3 Factors in the soil, such as its texture, its energy to retain water, and the amount of thoroughgoing affaire contained in it, also usurp the amount of pesticide that will leave the argona.3 Some pesticides contribute to global warming and the depletion of the ozone layer.4 edit Ai rPesticides prat 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.5 Pesticides that are applied to crops nookie volatilize and whitethorn be blown by winds into nearby areas, potentially posing a threat to wildlife.6 Also, droplets of sprayed pesticides or particles from pesticides applied as dusts may expire on the wind to other areas,7 or pesticides may adhere to particles that blow in the wind, such as dust particles.8 Ground spraying produces less(prenominal) pesticide drift than aerial spraying does.9 Farmers git employ a buffer zone around their crop, consisting of empty land or non-crop plants such as evergreen trees to help as windbreaks and absorb the pesticides, preventing drift into other areas.10 Such windbreaks are legally required in the Netherlands.10Pesticides that are sprayed on to fields and use to fumigate soil can give off chemicals called volatile organic compounds, which can react with other chemicals and form a pollutant called tropospheric ozone. Pesticide use accounts for about 6 percent of sum up tropospheric ozone levels.11 edit WaterIn the United States, pesticides were instal to pollute e really stream and over 90% of rise up sampled in a study by the US Geological Survey.12 Pesticide residues have also been found in rain and groundwater.3 Studies by the UK presidential term showed that pesticide concentrations exceeded those allowable for drinking water in some samples of river water and groundwater.13Pesticide impacts on aquatic systems are often studied using a hydrology transport model to study social movement and fate of chemicals in rivers and streams. As early as the 1970s quantitative analysis of pesticide runoff was conducted in order to predict amounts of pesticide that would reach surface waters.14There are four major routes done which pesticides reach the water it may drift outside of the i ntended 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.15 They may also be carried to water by eroding soil.16 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.17Maximum limits of allowable concentrations for individual pesticides in public bodies of water are set by the Environmental Protection Agency in the US.317 Similarly, the government of the United Kingdom sets Environmental Quality Standards (EQS), or maximum allowable concentrations of some pesticides in bodies of water above which toxicity may occur.18 The European Union also regulates maximum concentrations of pesticides in water.18 edit Soil many a(prenominal) of the chemicals used in pesticides are per sistent soil contaminants, whose impact may endure for decades and adversely affect soil conservation.19The use of pesticides decreases the general biodiversity in the soil. Not using the chemicals results in higher soil quality,verification needed20 with the spare effect that more organic matter in the soil allows for higher water retention.3 This helps increase yields for farms in drought years, when organic farms have had yields 20-40% higher than their conventional counterparts.21 A smaller content of organic matter in the soil increases the amount of pesticide that will leave the area of application, because organic matter binds to and helps break down pesticides.3 edit Effects on biotaedit PlantsNitrogen fixation, which is required for the growth of higher plants, is hindered by pesticides in soil.22 The insecticides DDT, methyl group parathion, and especially pentachlorophenol have been shown to interfere with legume-rhizobium chemical signaling.22 Reduction of this symbiot ic chemical signaling results in cut down nitrogen fixation and thus reduced crop yields.22 Root nodule formation in these plants saves the area economy $10 billion in synthetic nitrogen fertilizer every year.23Pesticides can butcher bees and are strongly implicated in pollinator decline, the loss of species that pollinate plants, including through the mechanism of Colony separate Disorder,24252627 in which worker bees from a beehive or Western honey bee colony abruptly disappear. practical application of pesticides to crops that are in bloom can bulge out honeybees,5 which act as pollinators. The USDA and USFWS estimate that US farmers lose at least $200 million a year from reduced crop pollenation because pesticides applied to fields eliminate about a fifth of honeybee colonies in the US and stultification an additional 15%.1On the other side, pesticides have some direct harmful effect on plant including poor root hair development, shoot yellowing and reduced plant growth 2 8. edit AnimalsPesticides inflict extremely widespread damage to biota, and many countries have acted to discourage pesticide usage through their Biodiversity Action Plans.citation neededAnimals may be poisoned by pesticide residues that remain on food after spraying, for example when wild animals enter sprayed fields or nearby areas shortly after spraying.9Widespread application of pesticides can eliminate food sources that certain types of animals need, causation the animals to relocate, change their diet, or starve.5 Poisoning from pesticides can trigger up the food chain for example, skirts can be harmed when they eat insects and worms that have readd pesticides.5 Some pesticides can bioaccumulate, or build up to toxic levels in the bodies of organisms that consume them over time, a phenomenon that impacts species high on the food chain especially hard.5 edit BirdsBald eagles are commonplace examples of nontarget organisms that are impacted by pesticide use. Rachel Carsons landmark book Silent Spring dealt with the loss of raspberry bush species due to bioaccumulation of pesticides in their tissues. There is evidence that birds are continuing to be harmed by pesticide use. In the cultivated land of Britain, populations of ten different species of birds have declined by 10 million breeding individuals between 1979 and 1999, a phenomenon purview to have resulted from loss of plant and invertebrate species on which the birds feed.29 Throughout Europe, 116 species of birds are now threatened.29 Reductions in bird populations have been found to be associated with times and areas in which pesticides are used.29 In another example, some types of fungicides used in peanut farming are only slightly toxic to birds and mammals, but may kill off earthworms, which can in turn reduce populations of the birds and mammals that feed on them.9Some pesticides come in granular form, and birds and other wildlife may eat the granules, mistaking them for grains of food. 9 A few granules of a pesticide is enough to kill a small bird.9The herbicide paraquat, when sprayed onto bird eggs, causes growth abnormalities in embryos and reduces the number of chicks that hatch successfully, but virtually herbicides do not directly cause much harm to birds.9 Herbicides may endanger bird populations by reducing their habitat.9 edit Aquatic lifeFish and other aquatic biota may be harmed by pesticide-contaminated water.30 Pesticide surface runoff into rivers and streams can be highly lethal to aquatic life, sometimes killing all the fish in a particular stream.31Application of herbicides to bodies of water can cause fish kills when the beat(p) plants rot and use up the waters oxygen, suffocating the fish.30 Some herbicides, such as copper color sulfite, that are applied to water to kill plants are toxic to fish and other water animals at concentrations similar to those used to kill the plants.30 Repeated exposure to sublethal doses of some pesticides can cause physiological and behavioural changes in fish that reduce populations, such as abandonment of nests and broods, decreased immunity to disease, and increased mishap to avoid predators.30Application of herbicides to bodies of water can kill off plants on which fish depend for their habitat.30Pesticides can accumulate in bodies of water to levels that kill off zooplankton, the main source of food for young fish.32 Pesticides can kill off the insects on which some fish feed, causing the fish to travel farther in search of food and exposing them to greater risk from predators.30The faster a given pesticide breaks down in the surround, the less threat it poses to aquatic life.30 Insecticides are more toxic to aquatic life than herbicides and fungicides.30 edit AmphibiansSee also descend in amphibian populationIn the past several decades, decline in amphibian populations has been occurring all over the world, for unexplained reasons which are thought to be varied but of which pesticides may be a part.33Mixtures of multiple pesticides appear to have a cumulative toxic effect on frogs.34 Tadpoles from ponds with multiple pesticides chip in in the water take longer to metamorphose into frogs and are smaller when they do, decrease their ability to stay prey and avoid predators.34A Canadian study showed that exposing tadpoles to endosulfan, an organochloride pesticide at levels that are likely to be found in habitats near fields sprayed with the chemical kills the tadpoles and causes behavioral and growth abnormalities.35The herbicide atrazine has been shown to turn male frogs into hermaphrodites, decreasing their ability to reproduce.34 edit Humans See also Pesticide residuePesticides can enter the human body through inhalation of aerosols, dust and vapor that contain pesticides through oral exposure by consuming food and water and through dermal exposure by direct tactile sensation of pesticides with skin.36 Pesticides are sprayed onto food, especially fruits and vegetables, they exhaust into soils and groundwater which can end up in drinking water, and pesticide spray can drift and pollute the air.The personal effects of pesticides on human health are more harmful based on the toxicity of the chemical and the length and magnitude of exposure.37 Farm workers and their families experience the greatest exposure to agricultural pesticides through direct contact with the chemicals. But every human contains a percentage of pesticides found in fat samples in their body. Children are most susceptible and sensitive to pesticides due to their small size and underdevelopment.36 The chemicals can bioaccumulate in the body over time.Exposure to pesticides can range from mild skin irritation to birth defects, tumors, genetic changes, blood and typeface disorders, endocrine disruption, and even coma or death.38 Some pesticides, including aldrin, chlordane, DDT, dieldrin, endrin, heptachlor, hexachlorobenzene, mirex, and toxaphene, are considered POPs.39 POPs have the ability to volatilize and travel great distances through the atmosphere to become deposited in remote regions.39 The chemicals also have the ability to bioaccumulate and biomagnify, and can bioconcentrate (i.e. become more concentrated) up to 70,000 times their original concentrations.39 POPs may continue to poison non-target organisms in the environment and increase risk to humans40 by disruption in the endocrine, reproductive, and immune systems cancer neurobehavioral disorders,39 infertility and mutagenic effects, although very little is currently known about these chronic effects. Some POPs have been banned, while others continue to be used. edit Pest resistance