Environmental Effects of Pesticides Essay Example for Free

environmental effects of Pesticides EssayOver 98% of sprayed insecticides and 95% of herbicides reach a destination some early(a) than their target species, including nontarget species, air, water, bottom sediments, and food.1 Pesticide contaminates crop up 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 aerially, and when it is sprayed into water to kill algae.2 The amount of pesticide that migrates from the intend application atomic chip 18a is influenced by the particular chemicals properties its propensity for binding to soil, its vapor pressure, its water solubility, and its resistance to being broken down over time. 3 Factors in the soil, such(prenominal) as its texture, its ability to retain water, and the amount of organic matter contained in it, also affect the amount of pesticide that will leave the argona.3 Some pesticides contribute to globular warming and the depletion o f the ozone layer.4 edit AirPesticides feces 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 can volatilize and whitethorn be blown by winds into nearby areas, potentially posing a brat to wildlife.6 Also, droplets of sprayed pesticides or particles from pesticides applied as dusts may travel 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 pesticide drift than aerial spraying does.9 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.10 Such windbreaks are legally required in the Netherlands.10Pesticides that are sprayed on to fields and expendd 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 total tropospheric ozone levels.11 edit WaterIn the United States, pesticides were imbed to pollute every stream and over 90% of well sampled in a study by the US Geological Survey.12 Pesticide residues live with also been found in rain and groundwater.3 Studies by the UK government showed that pesticide concentrations exceeded those allowable for deglutition water in some samples of river water and groundwater.13Pesticide shams on aquatic systems are often studied using a hydrology transport model to study fecal matter 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.14thither 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.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, w cancel outher, soil type, front 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 preceding(prenominal) which ototoxicity may occur.18 The European Union also regulates maximum concentrations of pesticides in water.18 edit SoilMany of the chemicals used in pesticides are persistent 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 excess set 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 parathion, and especially pentachlorophenol have been shown to interfere with legume-rhizobium chemical signaling.22 Reduction of th is dependent chemical signaling results in trim nitrogen fixation and thus dressd crop yields.22 Root nodule formation in these plants saves the world saving $10 billion in synthetic nitrogen fertilizer every year.23Pesticides can kill bees and are strongly implicated in pollinator decline, the loss of species that fertilise plants, including through the mechanism of Colony Collapse Disorder,24252627 in which worker bees from a beehive or Western honey bee colony abruptly disappear. Application of pesticides to crops that are in bloom can kill honeybees,5 which act as pollinators. The USDA and USFWS estimate that US farmers lose at least $200 million a year from reduced crop pollination because pesticides applied to fields eliminate about a fifth of honeybee colonies in the US and harm 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 28. 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, causing the animals to relocate, change their diet, or starve.5 Poisoning from pesticides can travel up the food fibril for example, birds can be harmed when they eat insects and worms that have consumed 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 common examples of nontarget organisms that are impacted by pesticide use. Rachel Carsons landmark book Silent Spring dealt with the loss of bird species due to bioaccumulation of pesticides in their tissues. There is evidence that birds are continuing to be harmed by pesticide use. In the farmland of Britain, macrocosms of ten different species of birds have declined by 10 million genteelness individuals between 1979 and 1999, a phenomenon thought 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 most 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 dead plants rot and use up the waters oxygen, suffocating the fish.30 Some herbicides, such as copper 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 behavioral changes in fish that reduce population s, such as abandonment of nests and broods, decreased immunity to disease, and increased failure 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 environment, the less threat it poses to aquatic life.30 Insecticides are more toxic to aquatic life than herbicides and fungicides.30 edit Amphibians try also Decline 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 present in the water exhaust longer to metamorphose into frogs and are smaller when they do, decreasing their ability to catch prey and avoid predators.34A Canadian study showed that exposing tadpoles to endosulfan, an organochloride pesticide at levels that are belike 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 pitying 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 contact of pesticides with skin.36 Pesticides are sprayed onto food, especially fruits and vegetables, they secrete into soils and groundwater which can end up in drinking water, and pesticide spray can drift and pollute the air.The 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 nerve 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 atmos phere 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, period others continue to be used. edit Pest resistance