ABSTRACT
In this production, it was aimed to review differences, abundance and effects of insects, to produce an environmental friendly insecticide and the judicious ways it can be used.
Using laboratory and analytical methods which involves quantifying and reacting the chemical reagents. After test analysis, the insecticide was obtained by decanting method.
The result of the product was tested for and the insecticide proved effective.
In conclusion; the organophosphate chemicals used in this production though toxic, but are much quicker to break down than its counter part carbamates and pyrethroids
CHAPTER ONE
1.0 INTRODUTION
1.1 DESCRIPTION
Though often misunderstood and referred to only insecticide by some people, pesticide is basically a chemical or biological agents designed to control, incapacitate, kill, repel or prevent pest activities deemed undesirable or destructive.
Pesticides can also be considered as either
- a) Biodegradable pesticide; which can be broken down by microbes and other living beings into harmless compounds. Or
- b) Persistence pesticide; which may take months or years before they broken down. Example DDT.
Pesticides have become a widely accepted way to rid our homes and gardens relatively pest-free. The use of pesticide is so common that the term pesticide is often treated synonymous with plant protection product in agriculture use
1.2 TYPES OF PESTICIDE
There are many types of pesticide designed to control and manage all kinds of pest, these include:-
Insecticides
Herbicides
Avicides
Algaecides
Bactericides
Fungicides
Miticides
Nematicides
Virucides
Rodenticides
And their respective target pest groups are
Insects
Herbs/plants
Birds
Algae
Bacteria
Fungi
Mites
Nematodes
Virus and
Rodents.
These pesticides listed above are chemical formulations intended for preventing, destroying, repelling or mitigating their respective pest group. It is also a mixture of substance that can be used as a plant regulation, defoliant and desiccant, and it can kill potential disease-causing organisms.
Pests are considered undesirable and destructive because they are organisms that are harmful to us. Some of these pests eat our crops, while some spread diseases. Herbs are considered pest as well because they grow in the wrong places.
1.3 HISTORICAL BENEFITS AND DANGERS
1.3.1 BENEFITS
One may stand to ask, why can’t all the farmers just grow their food organically?
The world population is 5billion and growing, of those about 700million is undernourished. Over one-third of our food is lost to pest and without pesticide incorporation; the losses will probably be even higher. So it will be very difficult to feed the world organically. The answer unfortunately, is that with current agricultural methods and technologies, it is not possible to produce the quantities currently needed for the number of people living in the earth surface. Pesticide allows us to increase our harvest and feed more people.
In addition to applications in agriculture, pesticides have many other important uses. Many pests transmit diseases which are very dangerous to us. For example, in the past, malaria was one a serious disease that killed millions of people globally, to fight this problem, the use of pesticide DDT was incorporated to kill mosquitoes which transmitted the diseases. It was successful and the number of people who died from malaria reduced drastically.
In the US, million of people have allergic reactions to the cockroaches in their homes, pesticides in insect sprays and baits helped reduced this problem a lot.
1.3.2 DANGERS
Presently, we are using more pesticides than ever. Although most modern pesticides are much safer than their predecessors, a few of our commonly used pesticides are toxic.
Researchers indicated that youngsters in homes where household and garden pesticides are used are seven times as likely to develop childhood leukemia. Of the 80,000 pesticides and other chemicals in use today, 10% are recognized as carcinogeous. Farmers are prone to certain cancers, including stomach prostrate and brain cancers upon exposure to various kinds of toxic pesticides.
Another NCI study found a link between breast cancer in women and elevated levels of DDE, a metabolite of the pesticide DDT, in their fat tissue. Women with the highest levels of exposure to DDT had four times the breast cancer risk to women with the least exposure. In laboratory tests where high doses of pesticides were given, researchers have observed some significant health effects like genetic damage, reproductive problems and possible links to cancer associated with pesticides.
As pesticide issue is a very complex one, there is definitely a need for certain pesticides in such areas as agriculture and disease prevention, and yet there are also some obvious health risks from some of these chemicals e.g. DDT. As a pesticide, DDT was first used during World War II. It was first made in a laboratory in 1873 and also effective as an insect killer that it was called the “atomic bomb” of pesticides. After World War II, it was realized that DDT could be used on farms to control some common agricultural pests. In addition, it was also used to control certain insects which carried diseases like malaria and yellow fever. By 1970, there were worries about DDT’s environmental and health effects, as it is an extremely persistent pesticide. Finally in June 1972, the US Environmental Protection Agency (EPA) cancelled all the use of DDT on crops and houses.
1.3.3 STRUCTURE OF DDT
DDT (dichlorodiphenyltrichloroethane) is a colorless crystalline substance which is nearly insoluble in water but highly soluble in fats and most organic solvents. DDT is created by the reaction of trichloroethanol with chlorobenzene (C6H5Cl). Trade or other names for DDT include Anofex, Cesarex, Chlorophenothane, Dedelo, p,p-DDT, Dichlorodiphenyltrichloroethane, Dinocide, Didimac, Digmar, ENT 1506, Genitox, Guesapon, Guesarol, Gexarex, Gyron, Hildit, Ixodex, Kopsol, Neocid, OMS 16, Micro DDT 75, Pentachlorin, Rukseam, R50 and Zerdane. It kills insects by opening sodium ion channels in insects’ neurons, causing the neurons to fire spontaneously. This leads to spasms and eventual death. Insects with certain mutations in their sodium channel gene may be resistant to DDT and other similar insecticides. Figure 1.0 shows the structure of DDT.
Figure 1.0: Structure of DDT
However, DDT is indeed toxic. It has a disastrous effect on a variety of freshwater and marine beings. It was found to cause eggshell thinning in birds, especially eagles and hawks, which caused decreased reproductive rates. Sweden banned DDT in 1970, and the U.S. banned it in 1972, after months of hearings, because of environmental concerns. Though its negative effects on wildlife are axiomatic, its effects on humans are not as clear. DDT is linked with cancer, endocrine disruption, and reproductive and developmental effects.
1.4 Aims and objective of the study
1.5 Pros and cons
1.5.1 Pros
A pesticide is defined under FIFRA as ”any substance or mixture of substances intended for preventing, destroying, repelling, or mitigating any insects, rodents, nematodes, fungi, or weeds, or any other forms of life declared to be pests, and any substance or mixture of substances intended for use as a plant regulator, defoliant, or desiccant.”
Pesticides have been used by humankind for centuries. Their use was recorded as early as the eighth century BC when the application of fungicides was documented in Homeric poems (Mason, 1928; McCallan, 1967). From the until the present, numerous mixtures have been developed to control fungi, insects, weeds, and other pests.
In the 19th century, sulfur compounds were developed as fungicides, and arsenicals were used to control insects attacking fruits and vegetables. Those compounds were highly toxic and consequently were replaced by chlorinated organic pesticides such as DDT and benzenehexachloride (BHC), which were developed during the 1930s and became widely used in the 1950s and 1960s. Chlorinated hydrocarbon insecticides such as DDT, BHC, dieldrin, aldrin, and toxaphene were enthusiastically adopted by farmers who hoped to control previously uncontrolled insects with what were believed to be relatively safe compounds with long environmental persistence. These chemicals were also used widely in the control of malaria and other insectborne diseases. By 1955, more than 90% of all pest control chemicals used in U.S. agriculture were synthetic organic compounds, and in 1961 DDT was registered for use on 334 crops. Phenoxy herbicides such as 2,4-dichlorophenoxyacetic acid (2,4-D), 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), and ethylenebisdithiocarbamates (EBDCs) and dicarboximide fungicides also gained widespread use during that time.
Beginning in the late 1960s, the potential of the chlorinated hydrocarbons for bioaccumulation and long-term toxicity became widely recognized. Also, pest resistance to chlorinated pesticides became increasingly evident and problematic throughout the 1960s, leading many farmers to substitute organophosphates and carbamates for DDT and other chlorinated compounds. Public pressure to end the use of chlorinated pesticides contributed to the creation of the Environmental Protection Agency (EPA) in 1970 and the ultimate administrative revocation in 1972 of the use of DDT on all food sources in the United States. By the end of the 1980s, most food uses of chlorinated compounds were discontinued in this country, although heavy application continues in other nations.
Since the late 1960s, a decline has occurred in insecticide use on major commodities such as corn, soybeans, cotton, and wheat. This decrease was primarily the result of pest management programs, which led to an approximately 50% reduction in pesticide application to cotton crops nationwide. Another important factor was the development and widespread adoption of synthetic pyrethroid compounds, which are applied in gram quantities rather than pounds per acre. During this period, fungicide use on peanuts and wheat declined, but because of the continued application of fungicides to fruits and vegetables and the increasing acreage of those crops under cultivation, the overall volume of fungicides used has remained steady.
In contrast, the use of herbicides has increased dramatically. In 1955 approximately 3% of all acreage planted with corn and soybean crops were treated with a herbicide; by 1985 that figure had increased to more than 95%, primarily because of the development of effective herbicides that were applied before the crop was planted. Herbicides now account for approximately 66% of all agricultural pesticides, but for a lower percentage of dietary exposure than is attributed to fungicides and insecticides, which are applied directly to the food closer to, or even after, its harvest. More than 90% of all herbicides are applied to just four crops: corn, soybeans, cotton, and wheat.
Today, most pesticides are synthetically produced organic and inorganic chemicals or microbial agents. Some of these pesticides have been found naturally and have been synthetically reproduced for commercial use. The variety and amounts of pesticides now used are far greater than at any previous time in human history. Approximately 600 pesticides are currently registered with the EPA (P. Fenner-Crisp, EPA, personal commun., 1993).
The most common food-use pesticides fall into three classes: insecticides, herbicides, and fungicides. In 1991, an estimated 817 million pounds of active pesticide ingredients were used for agricultural application in the United States. Of this total, herbicides accounted for 495 million pounds; insecticides, 175 million pounds, fungicides, 75 million pounds; and other pesticides, 72 million pounds; (EPA, 1992). “Other” pesticides were defined as rodenticides, fumigants, and molluscicides but do not include wood preservatives, disinfectants, and sulfur.
- Insecticides. Insecticides control insects that damage crops through a variety of modes. Some work as nerve poisons, muscle poisons, desiccants, sterilants, or pheromones; others exert their effects by physical means such as by clogging air passages. The classes of insecticides most commonly used today are chlorinated hydrocarbons, organophosphates, and carbamates, and of these, the organophosphates are the most widely used. Typically they are very acutely toxic, but they do not persist in the environment. Well-known organophosphate pesticides include parathion, dichlorvos, malathion, chlorpyrifos, and azinphos-methyl. The toxicity to humans resulting from exposure to these compounds can differ markedly from chemical to chemical.
The carbamate insecticides are also very widely used in the United States today. They too are highly toxic, e.g., aldicarb. Other insecticides such as synthetic pyrethroids, e.g., permethrin, are valued because of their fast action and relatively low toxicity to mammals.
- Herbicides. Herbicides are used to control weeds, which compete with crop plants for water, nutrients, space and sunlight. By reducing the weed population, the need for farm labor is decreased and crop quality is enhanced. Herbicides work through a variety of modes of action. Some damage leaf cells and desiccate the plant; others alter nutrient uptake or photosynthesis. Some herbicides inhibit seed germination or seedling growth. Others are applied to foliage and kill on contact, thereby destroying leaf and stem tissues. Some of the most widely used herbicides are 2,4-D [(2,4-dichlorophenoxy) acetic acid], atrazine, simazine, dacthal, alachlor, metolachlor, and glyphosate.
Fungicides. Fungicides control plant molds and other diseases. They include compounds of metals and sulfur as well as numerous synthetics. Some fungicides act by inhibiting the metabolic processes of fungal organisms and can be used on plants that have already been invaded and damaged by the organism. Other fungicides protect plants from fungal infections and retard fungal growth before damage to plants can occur. Fungicides frequently provide direct benefit to humans by retarding or eliminating fungal infections that can produce toxicants such as aflatoxins. Fungicides that have been used heavily over the years include benomyl, captan, and the EBDC family of fungicides such as mancozeb.
In addition to their agricultural applications, pesticides are also used for many nonagricultural purposes, e.g., in homes and public buildings to kill termites and other pests; on lawns and ornamental plantings to kill weeds, insects, and fungi; and on ponds, lakes, and rivers to control insects and weeds. Therefore, humans are exposed to pesticides from a variety of sources other than the diet, for example, through the skin or by inhalation. Some of these exposures are especially important when considering total exposures of infants and children.
1.5.2 ConsBottom of Form
Pesticide use raises a number of environmental concerns, including human and animal health hazards. Food contaminated with toxic pesticides is associated with severe effects on the human health because it is the basic necessity of life. Over 98% of sprayed insecticides and 95% of herbicides reach a destination other than their target species, including non-target species, air, water and soil .
Pesticide toxicity can result from ingestion, inhalation or dermal absorption. Continued exposure to these chemicals for a long period may result in various diseases some of which are listed below:
– Neurological, psychological and behavioral dysfunctions;
– Hormonal imbalances, leading to infertility, breast pain;
– Іmmune system dysfunction;
– Reproductive system defects;
– Cancers;
– Genotoxicity;
– Blood disorders.
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.
Recent articles and reports review toxicological and epidemiological evidences for various health effects associated with pesticides . Extensive toxicological studies in animals demonstrate that a number of pesticides to which the general population may be chronically exposed are potential carcinogens, neurotoxins, reproductive toxins, and immunotoxins . Gonz{lez with colleagues showed DNA damages under 2,4-D exposure in Chinese Hamster ovary cells (CHO). There are evidences on involvement of pesticides in development of neurodegenerative diseases . Many scientists reported impact of pesticides on biochemical parameters, in particular on protein metabolism , endocrine , and reproductive systems .
Pesticide contamination of both surface and ground waters can affect aquatic fauna and flora, as well as human health when water is used for public consumption . Aquatic organisms are directly exposed to chemicals resulting from agricultural production via surface run-off or indirectly through trophic chains.
DISCLAIMER:
All project works, files and documents posted on this website, projects.ng are the property/copyright of their respective owners. They are for research reference/guidance purposes only and the works are crowd-sourced. Please don’t submit someone’s work as your own to avoid plagiarism and its consequences. Use it as a guidance purpose only and not copy the work word for word (verbatim). Projects.ng is a repository of research works just like academia.edu, researchgate.net, scribd.com, docsity.com, coursehero and many other platforms where users upload works. The paid subscription on projects.ng is a means by which the website is maintained to support Open Education. If you see your work posted here, and you want it to be removed/credited, please call us on +2348159154070 or send us a mail together with the web address link to the work, to hello@projects.ng. We will reply to and honor every request. Please notice it may take up to 24 - 48 hours to process your request.