Regulation of Pesticides Pesticides are tested and approved for use by the Environmental Protection Agency (EPA), which establishes “tolerances,” or maximum residue levels, that limit the amount of a given pesticide that can safely remain in or on a food. The Food and Drug Administration (FDA) is then responsible for monitoring pesticide levels on fruits and vegetables, while the Department of Agriculture (USDA) is charged with the task of surveying pesticide residues in meat, eggs and dairy products.
Many believe that the Pea’s methods for testing pesticides are insufficient because they only examine the effects of exposure to pesticides at high doses. Without conducting research concerning long-term exposure to low doses of pesticides, these studies neglect to base safety levels on real-life situations. Moreover, the tests examine the effects of a single chemical, whereas people are typically contaminated with small amounts of hundreds of pesticides at any one time. The FDA is also criticized for its inadequate monitoring of pesticide levels on fruits and vegetables.
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Effect on plants Nitrogen fixation, which is required for the growth of higher plants, is hindered by pesticides in soil. The insecticides EDT, methyl parathion, and especially phenolphthalein have been shown to interfere with legume- rhizome chemical signaling. Reduction of these symbiotic chemical signaling 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.
The effects of rice plants treated with various pesticides on feeding, survival rates and population growth susceptibility of the treated rice plants and amounts of free amino acids and sucrose were studied. Experiments indicated that the effects of the tested pesticides were dependent on nymph’s age, pesticide and their dose and time after application. Effects on soil By prerecord Many to 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 n drought years, when organic farms have had yields 20-40% higher than their conventional counterparts. 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. 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 fasciculation of pesticides which are dependent on organic matter in the soil. Weak organic acids have been shown to be weakly absorbed by soil, because of pH and mostly acidic structure. Absorbed chemicals have been shown to be less accessible to microorganisms.
Aging mechanisms are poorly understood but as residence times in soil increase, pesticide residues become more resistant to degradation and extraction as they lose biological activity. DISCUSSION The findings show that the pesticides do not only affect the rice but also the soil. The soil can lose its fertility because of pesticide. Crops especially rice of Bag City will not be destroyed anymore by the pest because of the use of pesticide however it decreases its quality and there will be possibilities of health problems because of these pesticides.
CONCLUSION Based and according to the findings and the research, we are concluding that pesticides have a lot and different kinds of effect not only to the soil or health but meanly to the crop itself. RECOMMENDATION Base on the data and the conclusion. We would like to give the following recommendations to lessen the destruction of crops because of the pest at the same time produce a healthy and high standard rice. . Find a more harmless pesticide to your crops. 2. As long as there is no need for you to use pesticide, do not use it. . You can use The Fate Process, Fate processes fall into three major types: adsorption, transfer, and degradation. Pesticide adsorption The adsorption process binds pesticides to soil particles, similar to iron filings or paper clips sticking to a magnet. Adsorption oaten occurs because to the attraction between a chemical and soil particles. Positively charged pesticide molecules, for example, are attracted to and can bind to negatively charged clay particles. Many soil factors influence pesticide adsorption.
Soils high in organic matter or clay are more adsorptive than coarse, sandy soils, in part because a clay or organic soil has more particle surface area, or more sites onto which pesticides can bind. Moisture also affects adsorption. Wet soils tend to adsorb less pesticide than dry soils because water molecules compete with the pesticide for the binding sites. Pesticides vary in their adsorption to soil particles. Some pesticides such as parquet and glasshouse bind very tightly, while others bind only weakly and are readily desorbed or released back into the soil solution.
One problem resulting from pesticide adsorption is educed pest control. For example, weeds may not be controlled if a herbicide is held tightly to soil particles and cannot be taken up by the roots of the target weeds. Some pesticide labels recommend higher application rates when the chemical is applied to adsorptive soils. Plant injury can be another problem resulting from adsorption of pesticides to soil particles. Injury can result when a pesticide used for one crop is later released from the soil particles in amounts great enough to cause injury to a sensitive rotational crop.
This pesticide carry-over can also lead to the presence of illegal residues on rotational food or feed crops. Adsorption is particularly important because it influences whether other processes are able to affect pesticides. Pesticide transfer Pesticide transfer is sometimes essential for pest control. For example, for certain preeminence herbicides to be effective, they must move within the soil to reach the germinating seeds. Too much movement, however, can move a pesticide away from the target pest.
This can lead to reduced pest control, contamination of surface water and groundwater, and injury of montage species, including humans. Five ways that pesticides can be transferred are through popularization, runoff, leaching, absorption ND crop removal. Popularization Popularization is the conversion of a solid or liquid into a gas. Once volatile, a pesticide can move in air currents away from the treated surface. Vapor pressure is an important factor in determining whether a pesticide will volatility. The higher the vapor pressure, the more volatile the pesticide.
Environmental factors tend to increase popularization. They include high temperature, low relative humidity, and air movement. A pesticide tightly adsorbed to soil particles is less likely to volatility; soil conditions such as texture, organic matter content, and moisture can thus influence suicide popularization. Popularization can result in reduced control of the target pest because less pesticide remains at the target site. Vapor drift, the movement of pesticide vapors or gases in the atmosphere, can lead to injury of montage species. Herbicide vapors in particular can injure montage plants.
To reduce pesticide popularization, avoid applying volatile pesticides when conditions are unfavorable, such as very hot, dry days or when the soils are wet. Labels often provide warnings if there is a volatility hazard under certain conditions. Labels for volatile pesticides may suggest adding the pesticide to the soil by tillage or irrigation during or shortly after application. This helps to reduce popularization by reducing the amount of exposed pesticide on the soil surface. Low-volatile formulations are also available for some pesticides. Runt Runoff is movement of water over a sloping surface.
Runoff occurs when water is applied faster than it can enter the soil. Pesticides can be carried in the water itself or bound to eroding soil particles. The severity of pesticide runoff depends on the slope or grade of an area; the readability, texture and moisture content of the soil; ND the amount and timing of rainfall and irrigation. Pesticide runoff usually is greatest when a heavy or sustained rain follows soon after an application. Over- irrigation can lead to excess surface water; it also can lead to pesticide runoff, especially when an irrigation system is used to apply a pesticide.
Vegetation or crop residue tends to slow the movement of runoff water. Certain physical and chemical properties of the pesticide, such as how quickly it is absorbed by plants or how tightly it is bound to plant tissue or soil, are also important. Herbicide runoff can cause direct injury to montage plants. Insecticide and matricide runoff into surface waters such as streams and ponds can be particularly harmful to aquatic organisms. Pesticide runoff also can lead to groundwater contamination and can cause injury to crops, livestock or humans if the contaminated water is used downstream.
Practices to reduce pesticide runoff include monitoring of weather conditions, careful application of irrigation water, using a spray mix additive to enhance pesticide retention on foliage, and incorporating the pesticide into the soil. Reduced-tillage cropping systems and surface grading, in addition to contour planting and strip roping of untreated vegetation, can slow the movement of runoff water and help keep it out of wells, sinkholes, water bodies and other sensitive areas. Leaching Leaching is the movement of pesticides through the soil rather than over the surface.
Leaching depends, in part, on the pesticide’s chemical and physical properties. For example, a pesticide held strongly to soil particles by adsorption is less likely to leach. Another factor is solubility. A pesticide that dissolves in water can move with water in the soil. The persistence, or longevity, of a pesticide also influences the likelihood of caching. A pesticide that is rapidly broken down by a degradation process is less likely to leach because it may remain in the soil only a short time. Soil factors that influence leaching include texture and organic matter, in part because of their effect on pesticide adsorption.
Soil permeability (how readily water moves through the soil) is also important. The more permeable a soil, the greater potential for pesticide leaching. A sandy soil is much more permeable than a clay. The method and rate of application, the use of tillage systems that modify soil conditions, and the amount ND timing of water a treated area receives after application can also influence pesticide leaching. Typically, the closer the time of application to a heavy or sustained rainfall, the greater the likelihood that some pesticide leaching will occur.
A certain amount of pesticide leaching may be essential for control of a target pest. Too much leaching, however, can lead to reduced pest control, injury of montage species and groundwater contamination. Monitoring weather conditions and the amount and timing of irrigation can help minimize pesticide leaching. Careful pesticide selection is important because those pesticides that are not readily desorbed, not rapidly degraded, and highly water soluble are the most likely to leach. Labels must be read carefully for instructions on the rates, timing and methods of application.
The label may also advise against using the pesticide when certain soil, geologic or climatic conditions are present . Pesticides can leach through the soil to groundwater from storage, mixing, equipment cleaning and disposal areas. Under certain conditions, some pesticides can leach to groundwater from normal applications. The section “Pesticides and water quality” provides further discussion on groundwater and safe handling practices to prevent contamination. Absorption or uptake Absorption or uptake is the movement of pesticides into plants and animals.
Absorption of pesticides by target and montage organisms is influenced by environmental conditions and by the chemical and physical properties of the pesticide and the soil. Once absorbed by plants, pesticides may be broken down or they may remain in the plant until tissue decay or harvest. Crop removal Crop removal transfers pesticides and their breakdown products from the treatment site. Most harvested food commodities are subjected to washing and processing procedures that remove or degrade much of the remaining pesticide residue.
While we typically associate harvesting with food and feed products, it is easy to forget that pesticides potentially can be transferred during such operations as tree and shrub pruning and trigrams mowing. Pesticide degradation Pesticide degradation, or the breakdown of pesticides, usually is beneficial. Pesticide- destroying reactions change most pesticide residues in the environment to nontoxic or harmless compounds. However, degradation is detrimental when a pesticide is destroyed before the target pest has been controlled.
Three types of pesticide degradation are microbial, chemical, and photoengraving. Microbial degradation Microbial degradation is the breakdown of pesticides by fungi, bacteria, and other microorganisms that use pesticides as a food source. Most microbial degradation of pesticides occurs in the soil. Soil conditions such as moisture, temperature, aeration, pH, and the amount of organic matter affect the rate of microbial degradation because of their direct influence on microbial growth and activity.
The frequency of pesticide application also is a factor that can influence microbial degradation. Rapid microbial degradation is more likely when the same pesticide is used repeatedly in a field. Repeated applications can actually stimulate the buildup of organisms that are effective in degrading the chemical. As the population of these organisms increases, degradation accelerates and the amount of pesticide available to control the pest is reduced. In extreme cases, accelerated microbial degradation has led to certain products being removed from the marketplace.
Microorganisms greatly reduce the effectiveness of these chemicals soon after application. The possibility of very rapid pesticide breakdown is reduced by using pesticides only when necessary and by avoiding repeated applications of the same chemical. Alternating between different classes, groups or formulations of pesticides can minimize the potential for microbial degradation problems as well as pest resistance. Chemical degradation Chemical degradation is the breakdown of pesticides by processes that do not involve living organisms.
Temperature, moisture, pH and adsorption, in addition to the chemical and physical properties of the pesticide, determine which chemical reactions take place and how quickly they occur. One of the most common pesticide degradation reactions is hydrolysis, a breakdown process in which the pesticide reacts with water. Many orchestrating and carbonate insecticides are particularly susceptible to hydrolysis under alkaline conditions. Some are actually broken down within a matter of hours when mixed with alkaline water.
Product labels may warn against mixing a pesticide with certain fertilizers, other pesticides or water with specific characteristics. Following these precautions can help prevent pesticide degradation and potential incompatibility problems. In some situations, buffers or other additives may be available to modify spray mix conditions and prevent or reduce degradation. Pesticide degradation and possible corrosion of application equipment can be avoided by not allowing a spray mix to remain in a tank for a long period of time.
Photoengraving Photoengraving is the breakdown of pesticides by light, particularly sunlight. Photoengraving can destroy pesticides on foliage, on the surface of the soil, and even in the air. Factors that influence pesticide photoengraving include the intensity of the sunlight, properties of the application site, the application method and the properties of the pesticide. Pesticide losses from photoengraving can be reduced by adding the pesticide to the soil during or immediately after application.