Impact Of Pesticides Used In Agriculture Their Benefits And Hazards Pdf

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Population size of Tadaria brasiliensis at Carlsbad Caverns in Distribution of oxadiazon and phoslone in an aquatic model ecosystem. Andreu V, Pico' Y.

Pesticides are substances that are meant to control pests. As an example - The fungus Alternaria is used to combat the Aquatic weed, Salvinia. In general, a pesticide is a chemical such as carbamate or biological agent such as a virus , bacterium , or fungus that deters, incapacitates, kills, or otherwise discourages pests. Target pests can include insects, plant pathogens , weeds, molluscs , birds , mammals , fish , nematodes roundworms , and microbes that destroy property, cause nuisance, or spread disease, or are disease vectors.

Impact of pesticides use in agriculture: their benefits and hazards

Pesticides are substances that are meant to control pests. As an example - The fungus Alternaria is used to combat the Aquatic weed, Salvinia. In general, a pesticide is a chemical such as carbamate or biological agent such as a virus , bacterium , or fungus that deters, incapacitates, kills, or otherwise discourages pests. Target pests can include insects, plant pathogens , weeds, molluscs , birds , mammals , fish , nematodes roundworms , and microbes that destroy property, cause nuisance, or spread disease, or are disease vectors.

Along with these benefits, pesticides also have drawbacks, such as potential toxicity to humans and other species. Pesticides can be classified by target organism e. These include the pyrethroids , rotenoids , nicotinoids , and a fourth group that includes strychnine and scilliroside. Many pesticides can be grouped into chemical families. Prominent insecticide families include organochlorines , organophosphates , and carbamates.

Organochlorine hydrocarbons e. Their toxicities vary greatly, but they have been phased out because of their persistence and potential to bioaccumulate. Both operate through inhibiting the enzyme acetylcholinesterase , allowing acetylcholine to transfer nerve impulses indefinitely and causing a variety of symptoms such as weakness or paralysis.

Organophosphates are quite toxic to vertebrates and have in some cases been replaced by less toxic carbamates. Prominent families of herbicides include phenoxy and benzoic acid herbicides e.

Phenoxy compounds tend to selectively kill broad-leaf weeds rather than grasses. The phenoxy and benzoic acid herbicides function similar to plant growth hormones, and grow cells without normal cell division, crushing the plant's nutrient transport system. The application of pest control agents is usually carried out by dispersing the chemical in an often hydrocarbon-based solvent - surfactant system to give a homogeneous preparation.

A virus lethality study performed in demonstrated that a particular pesticide did not increase the lethality of the virus, however, combinations that included some surfactants and the solvent clearly showed that pretreatment with them markedly increased the viral lethality in the test mice.

Pesticides can be classified based upon their biological mechanism function or application method. Most pesticides work by poisoning pests. With insecticides and most fungicides, this movement is usually upward through the xylem and outward. Increased efficiency may be a result. Systemic insecticides, which poison pollen and nectar in the flowers , may kill bees and other needed pollinators. In , the development of a new class of fungicides called paldoxins was announced.

These work by taking advantage of natural defense chemicals released by plants called phytoalexins , which fungi then detoxify using enzymes. The paldoxins inhibit the fungi's detoxification enzymes. They are believed to be safer and greener. Since before BC, humans have utilized pesticides to protect their crops. The first known pesticide was elemental sulfur dusting used in ancient Sumer about 4, years ago in ancient Mesopotamia.

The Rigveda , which is about 4, years old, mentions the use of poisonous plants for pest control. In the 17th century, nicotine sulfate was extracted from tobacco leaves for use as an insecticide.

The 19th century saw the introduction of two more natural pesticides, pyrethrum , which is derived from chrysanthemums , and rotenone , which is derived from the roots of tropical vegetables. Organochlorines such as DDT were dominant, but they were replaced in the U. Since then, pyrethrin compounds have become the dominant insecticide. The first legislation providing federal authority for regulating pesticides was enacted in ; [16] however, decades later during the s manufacturers began to produce large amounts of synthetic pesticides and their use became widespread.

Environmental Protection Agency was established in and amendments to the pesticide law in , [16] pesticide use has increased fold since and 2. In the s, it was discovered that DDT was preventing many fish-eating birds from reproducing, which was a serious threat to biodiversity.

Rachel Carson wrote the best-selling book Silent Spring about biological magnification. The agricultural use of DDT is now banned under the Stockholm Convention on Persistent Organic Pollutants, but it is still used in some developing nations to prevent malaria and other tropical diseases by spraying on interior walls to kill or repel mosquitoes.

Pesticides are used to control organisms that are considered to be harmful, or pernicious to their surroundings. They can also kill bees , wasps or ants that can cause allergic reactions.

Insecticides can protect animals from illnesses that can be caused by parasites such as fleas. Herbicides can be used to clear roadside weeds, trees, and brush. They can also kill invasive weeds that may cause environmental damage. Herbicides are commonly applied in ponds and lakes to control algae and plants such as water grasses that can interfere with activities like swimming and fishing and cause the water to look or smell unpleasant. Each use of a pesticide carries some associated risk.

DDT , sprayed on the walls of houses, is an organochlorine that has been used to fight malaria since the s. Recent policy statements by the World Health Organization have given stronger support to this approach.

DDT use is not always effective, as resistance to DDT was identified in Africa as early as , and by nineteen species of mosquito worldwide were resistant to DDT.

In and , the world used approximately 2. In and the U. Pesticides are also found in majority of U. Insecticide use in the US has declined by more than half since In corn fields, the decline was even steeper, due to the switchover to transgenic Bt corn.

Pesticides can save farmers' money by preventing crop losses to insects and other pests; in the U. There are two levels of benefits for pesticide use, primary and secondary.

Primary benefits are direct gains from the use of pesticides and secondary benefits are effects that are more long-term. Controlling pests and plant disease vectors. In general, farmers benefit from having an increase in crop yield and from being able to grow a variety of crops throughout the year. Consumers of agricultural products also benefit from being able to afford the vast quantities of produce available year-round. On the cost side of pesticide use there can be costs to the environment , costs to human health, [38] as well as costs of the development and research of new pesticides.

Pesticides may cause acute and delayed health effects in people who are exposed. The American Academy of Pediatrics recommends limiting exposure of children to pesticides and using safer alternatives: [47]. One study found pesticide self-poisoning the method of choice in one third of suicides worldwide, and recommended, among other things, more restrictions on the types of pesticides that are most harmful to humans.

A epidemiological review found associations between autism and exposure to certain pesticides, but noted that the available evidence was insufficient to conclude that the relationship was causal. See also: Environmental Impact of Pesticides. Records indicate an increase in the frequency of pesticide poisonings over the past two decades. The most common incidents of pesticide poisoning is thought to result from exposure to organophosphate and carbamate insecticides.

Underreporting of pesticide poisoning is especially common in areas where agricultural workers are less likely to seek care from a healthcare facility that may be monitoring or tracking the incidence of acute poisoning. The extent of unintentional pesticide poisoning may be much greater than available data suggest, particularly among developing countries.

Globally, agriculture and food production remain one of the largest industries. In some countries in East Africa, governments are shifting towards commercial agriculture , and opportunities for foreign conglomerates to operate commercial farms has led to more accessible research on pesticide use and exposure among workers. In other areas where large proportions of the population rely on subsistence, small-scale farming, estimating pesticide use and exposure is more difficult.

Pesticides may exhibit toxic effects on humans and other non-target species, the severity of which depends on the frequency and magnitude of exposure. Toxicity also depends on the rate of absorption, distribution within the body, metabolism, and elimination of compounds from the body. Commonly used pesticides like organophosphates and carbamates act by inhibiting acetylcholinesterase activity, which prevents the breakdown of acetylcholine at the neural synapse.

Excess acetylcholine can lead to symptoms like muscle cramps or tremors, confusion, dizziness and nausea. Studies show that farm workers in Ethiopia, Kenya, and Zimbabwe have decreased concentrations of plasma acetylcholinesterase, the enzyme responsible for breaking down acetylcholine acting on synapses throughout the nervous system. There are multiple approaches to measuring a person's exposure to pesticides, each of which provides an estimate of an individual's internal dose. Two broad approaches include measuring biomarkers and markers of biological effect.

Markers of biological effect provide an estimation of exposure based on cellular activities related to the mechanism of action. For example, many studies investigating exposure to pesticides often involve the quantification of the acetylcholinesterase enzyme at the neural synapse to determine the magnitude of the inhibitory effect of organophosphate and carbamate pesticides.

Another method of quantifying exposure involves measuring, at the molecular level, the amount of pesticide interacting with the site of action. Alternative methods to assess exposure include questionnaires to discern from participants whether they are experiencing symptoms associated with pesticide poisoning.

Self-reported symptoms may include headaches, dizziness, nausea, joint pain, or respiratory symptoms. Multiple challenges exist in assessing exposure to pesticides in the general population, and many others that are specific to occupational exposures of agricultural workers. Children may also be exposed to pesticides prenatally from mothers who are exposed to pesticides during pregnancy.

While measuring biomarkers or markers of biological effects may provide more accurate estimates of exposure, collecting these data in the field is often impractical and many methods are not sensitive enough to detect low-level concentrations. Rapid cholinesterase test kits exist to collect blood samples in the field. Conducting large scale assessments of agricultural workers in remote regions of developing countries makes the implementation of these kits a challenge.

However, considerable variability in baseline enzyme activity among individuals makes it difficult to compare field measurements of cholinesterase activity to a reference dose to determine health risk associated with exposure. More epidemiological research is needed to identify critical health endpoints, particularly among populations who are occupationally exposed.

Minimizing harmful exposure to pesticides can be achieved by proper use of personal protective equipment, adequate reentry times into recently sprayed areas, and effective product labeling for hazardous substances as per FIFRA regulations. Training high-risk populations, including agricultural workers, on the proper use and storage of pesticides, can reduce the incidence of acute pesticide poisoning and potential chronic health effects associated with exposure.

Continued research into the human toxic health effects of pesticides serves as a basis for relevant policies and enforceable standards that are health protective to all populations.

Pesticide use raises a number of environmental concerns. Pesticides are one of the causes of water pollution , and some pesticides are persistent organic pollutants and contribute to soil and flower pollen, nectar contamination. In addition, pesticide use reduces biodiversity , contributes to pollinator decline , [74] destroys habitat especially for birds , [75] and threatens endangered species. Alternatively a greater dose of the pesticide can be used to counteract the resistance, although this will cause a worsening of the ambient pollution problem.

Pesticides: Environmental Impacts and Management Strategies

Our populous, fast-paced world demands quality food that is affordable — and lots of it. In the short term, pesticides greatly assist pest control. In the long term, however, pesticides appear to harm the health of humans and the environment. A pesticide is any substance or mixture of substances whose purpose is to prevent, extinguish, or repel pests or to regulate plants. There are considerable benefits to pesticide use.

Pesticides, also known as pest control products, control, destroy or inhibit the activities of pests, and minimize their injurious, noxious or troublesome effects. If not properly managed, pests can affect our quality of life in many different ways. Pests can represent a threat to public health and the environment as well as create significant negative impacts to the economy if they are not efficiently controlled. The availability and use of pesticides have the potential to pose risks, both directly and indirectly, to the health, safety and well-being of people in Canada, and to the environment. As such, pesticides are highly regulated products.

Pesticides can contaminate soil, water, turf, and other vegetation. In addition to killing insects or weeds, pesticides can be toxic to a host of other organisms including birds, fish, beneficial insects, and non-target plants.

The Advantages and Disadvantages of Pesticides

Pesticides can cause short-term adverse health effects, called acute effects, as well as chronic adverse effects that can occur months or years after exposure. Examples of acute health effects include stinging eyes, rashes, blisters, blindness, nausea, dizziness, diarrhea and death. Examples of known chronic effects are cancers, birth defects, reproductive harm, neurological and developmental toxicity, immunotoxicity, and disruption of the endocrine system.

Toxicology Studies - Cells, Drugs and Environment. Pesticides constitute any substance or mixture of substances intended for preventing, destroying, repelling, or mitigating any pest. They can also serve as plant regulators, defoliants, or dessicants [ 1 ]. Chemicals have long been used to control pests.

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