The Past, Present, and Future of Pesticide Use and Bans

The past, present, and future of pesticide use and bans

TABLE OF CONTENTS

PESTICIDE BANS .................................................................................................................................2

INTRODUCTION........................................................................................................................2

THE STOCKHOLM CONVENTION........................................................................................2

DEMAND FOR PESTICIDE CONTROL.................................................................................3

PESTICIDES IN ONTARIO.......................................................................................................4

DDT...........................................................................................................................................................5

CHEMICAL PROPERTIES.......................................................................................................5

HISTORY OF DDT......................................................................................................................6

EFFECTS OF DDT......................................................................................................................7

DDT BANS...................................................................................................................................7

VECTOR CONTROL..................................................................................................................8

PESTICIDE ALTERNATIVES..............................................................................................................9

THE PROBLEM OF UNSUSTAINABILITY...........................................................................9

THE SOLUTION.......................................................................................................................10

INTERGRATED PEST MANAGEMENT...............................................................................10

ORGANIC ALTERNATIVES & APPLICATIONS................................................................11

CANADIAN TRENDS...............................................................................................................12

ECONOMIC EFFECTS OF REDUCED PESTICIDE USE.................................................13

CONCLUSION.......................................................................................................................................14

REFERENCES.......................................................................................................................................15

Pesticide Bans
Introduction
Farmed crops have been an important livelihood for centuries, but when losses from 10 to 90% occur because of pests and diseases, a solution was desperately needed. About 4500 years ago the Sumerians used sulfur compounds to control insects and mites, and following them were the Chinese who used mercury and arsenic to control body lice (Unsworth, 2010). Up until the 1940s, many products were organically derived, but following this time period synthetic pesticides were developed. Once the effectiveness of aldrin, DDT, dieldrin, endrin, and chlorodane was discovered, these became the primary pesticides because they were inexpensive and were not seen to cause any health risks at the time. DDT was especially helpful because of its ability to control lice and malaria, although with time some insects developed a resistance (Unsworth, 2010). Overall, pesticides have only gotten more potent and harmful over the years, and we are now trying to produce better alternatives and phase out the ones which are most harmful.

The Stockholm Convention The public has been using pesticides for decades, but has only recently realized the harmful effects that they are having on their health and the environment. These substances not only pollute our land and water, but they are now seen to cause major health risks. The Stockholm Convention was held in 2001 to put measures in place to rid the environment of the eight most harmful pesticides (UNIDO, 2011). These included aldrin, DDT, dieldrin, endrin, heptachlor, chlordane, mirex, and toxaphene. According to Table 10-2 in Environmental Chemistry(Baird & Cann, 2008), the United States, Canada, and United Kingdom have all put a ban on production and use of the above pesticides, or severely restricted them. China, India and Russia are also working on banning all eight, although they are still behind in the elimination of certain pesticides. For example, China has not yet banned or restricted use of DDT. In order to eliminate these pesticides, the Stockholm Convention promised to support the transition to safer alternatives, target additional chemicals for elimination, clean up old stockpiles of the chemicals that are still remaining after the ban, and to get the world to work together to promote a future free of these harmful pesticides (UNIDO, 2011). This agreement is the most important tool to ensure that these pesticides are banned throughout the world, because without the cooperation of the world elimination would be impossible, as they are able to travel throughout the world.

Demand for Pesticide Control Public health problems caused by the use of pesticides were realized nearly twenty years before action was actually taken to eliminate them from the environment. The public and the government took until the 1990’s to finally decide to react, and place municipal bans on harmful pesticides. Hudson, Quebec was the first municipality in Canada to decide to go to court against pesticide companies, and fight to put a by-law in effect to eliminate pesticides in 2001. They brought about the fact that most municipalities have the power to set by-laws to respond to community concerns, and to protect the welfare of the public (Cooper & McClenaghan, 2005). Once children were found to be most vulnerable to symptoms from pesticides such as birth defects, cancer, neurological dysfunction, and immunotoxicity, it made the public even more determined to rid these from their community. The most concerning fact about these pesticides is that they are present in just about everyone. It is virtually impossible to go through life without coming into contact with one of the 8 most harmful. They are present in the water, land, and even on the food we eat. Therefore, banning pesticides is the only way to prevent them from contaminating the future population and the environment.

Pesticides in Ontario In Ontario, the pesticide ban has been given a large priority. In 2009 there was a Pesticides Act put in to place to regulate the use of pesticides by pesticide companies and farmers by managing their transportation, storage, and disposal (Ministry of the Environment, 2010). Following that, there was an amendment called the Cosmetic Pesticide Act which aimed to reduce public exposure to pesticides. It prevents the use of pesticides for cosmetic use, in order to eliminate the unnecessary risk to small children and pets. Although these Acts should have been created much earlier, it is a good step to ensure that our future environment is free of these harmful pesticides.

DDT – Dichlorodiphenyltrichloroethane DDT was the first synthetic pesticide of the modern age. While initially very promising, it ultimately created widespread concern as an environmental hazard and health risk. This section will be devoted to understanding what about DDT makes it such an effective insecticide, as well as discussing negative health effects, and finally ban history and vector control.

Chemical Properties
Dichlorodiphenyltrichloroethane, also known as DDT, is an ethane chain, where on one Carbon atom, all 3 possible Hydrogen atoms have been exchanged for Chlorine atoms. On the other Carbon atom of this ethane chain, 2 of the Hydrogen atoms have been replaced by benzene rings, each with an attached chlorine atom, usually found at the para position, although also being found at the ortho position.
This compound is nearly insoluble in water, yet has good solubility in most organic solvents, fats and oils, while being hydrophobic, lipophilic, and a colorless crystalline solid (“DDT,” 2011). Due to this compounds lipophilic nature, DDT has the potential to bio accumulate within organisms. When this compound becomes introduced into an animal’s body, DDT is metabolized by taking off the Hydrogen atom from the Carbon with benzene rings, and by taking off a Chlorine atom from the adjacent Carbon (Baird & Cann, 2008). Essentially, this is like removing a Hydrogen Chloride atom, which then creates Dichlorodiphenyldichloroethylene, also known as DDE (Baird & Cann, 2008). DDE is a metabolite of DDT, meaning that DDE is one of the major components of DDT after it is broken down. DDE can be made by the degradation of DDT in an alkaline environment, and by DDT resistant insects which breakdown DDT into DDE through the process explained above (Baird & Cann, 2008). After some study of DDT in the environment, it was found that this compound possessed low vapor pressure, and a slow rate of evaporation, as well as a low reactivity with light, and to chemicals as well as microorganisms found in the environment (Baird & Cann, 2008). DDT is also strongly absorbed by soil, and when taken into account with the other characteristics of this compound, like the slow evaporation rate or low reactivity with light, one could see how the half-life of DDT found in soil can range between 22 days, up to 30 years, depending on the conditions present (“DDT,” 2011). Degradation of DDT can occur through runoff, volatilization, photolysis, and aerobic/anaerobic decomposition (“DDT,” 2011).

History of DDT DDT was first made in 1874, although not used as a pesticide until 1939 (Machipisa, 1996). This compound was found to have characteristics of a contact position against several arthropods, and was used in World War 2 to control malaria and typhus (“DDT,” 2011). Prior to 1940, pyrethrum was the insecticide du jour, only to be replaced by DDT, which aided in the elimination of typhus in Europe, as well as the elimination of malaria in Europe and North America (Machipisa, 1996). The World Health Organization, known as WHO, lead a program to eradicate malaria worldwide, relying on DDT as their “poster child” (“DDT,” 2011). Due to agricultural usage of DDT, a lot of resistant insects were able to live through this program (Anderson, 2011). “Early victories partially or completely reversed, and in some cases rates of transmission increased. The program was successful in eliminating malaria only in areas with “high socio-economic status, well organized healthcare systems, and relatively less intensive, or seasonal malaria transmission.”” (“DDT,” 2011).
DDT Bans In 1967, after the published book “Silent Spring” became a best seller, which was written by naturalist-author Rachel Carson, a group of scientists and lawyers founded the Environmental Defense Fund (EDF) to ban DDT (Anderson, 2011). As soon as 1968, DDT was banned for agricultural reasons in developed countries, still allowing use for vector control (Machipisa, 1996). The WHO lead program was abandoned in 1969, and instead influence was put into the control and treatment of this disease (“DDT,” 2011). Spraying of DDT was then switched to “bednets”, a synthetic container impregnated with insecticides and other interventions (“DDT,” 2011). As of 1972, the United States banned the use of DDT for most purposes, still allowing the usage for disease vector control (Anderson, 2011). In 2004, at the Stockholm Convention, DDT was banned worldwide for agricultural use, and allowed for disease vector control (“DDT,” 2011). Despite this ban, India is the only country to still produce DDT, and India and North Korea are still using DDT for agricultural use (“DDT,” 2011). Due to DDTs bioaccumulation properties, and its low rate of biodegradation, the effects from DDT usage dating back decades ago can still be felt today. Between 1950 and 1980, more than 40,000 tonnes of DDT were used each year on a global scale (Machipisa, 1996). DDT is found on the UN’s list of 12 persistent organic pollutants, and is the only compound on the list which is not totally banned (Baird et al., 2008).

Effects of DDT Both DDT and DDE have shown positive correlations between bioaccumulation levels in birds, and the thinning of eggs, with DDE having a stronger correlation than DDT (“DDT,” 2011). P,p’-DDE is able to inhibit calcium ATPase in the membrane of the shell gland, reducing the transportation of calcium carbonate across the membrane, into the eggshell gland, thus making the shell more brittle and thinner (Bell, 2011). Also, o,p’-DDT can disrupt the female reproductive tract development, disrupting the eggshell quality for the next generation (“DDT,” 2011). With this in mind, one could see how the ban on DDT has aided in the resurgence of bald eagles, brown pelicans, peregrine falcons, and ospreys (“DDT,” 2011). In insects, DDT opens the sodium channels found in neurons, and saturates them, causing them to fire spontaneously which results in death (“DDT,” 2011). A genetic mutation towards this reaction can produce resistance to DDT (“DDT,” 2011). DDT in humans however, can have a much wider effect then the over saturation of neurons. In humans, this compound can be genotoxic, or may induce enzymes to produce other genotoxic intermediates (Bell, 2011). Furthermore, DDT can cause endocrine disruption, diabetes, damage to the reproductive system, neurological problems, asthma, and even cancer (Bell, 2011).

Vector Control DDT is used for vector control in a method called Indoor Residual Spraying, or IRS for short (“DDT,” 2011). IRS is when DDT is applied to the inside walls of a home or building to kill and repel mosquitoes in order to control the spread of disease (“DDT,” 2011). Although vector control is a controversial matter, over 380 concerned scientists, representing 57 countries, signed a letter supporting the use of DDT for IRS in the attempt to control malaria (Roberts et al.,2000). Some groups disagree with the claims of risks of DDT towards human health, saying that these results have not been confirmed by replicated scientific inquiry (Roberts et al., 2000). Others, however, say that after autopsy’s, tissue sampled from people who have passed due to cirrhosis of the liver, cancer, and hypertension, showed concentrations of DDT and related compounds at 2 or 3 times the level of those in a controlled group (Sibley, 1997).

Pesticide Alternatives
The Problem of Unsustainability Over the years as pesticides have been allowed to permeate the environment, there has been an increasing awareness regarding the unsustainability of synthetic pesticide use, especially since the Stockholm Convention in 2001, where a light was shed on the main culprits contributing to negative health effects and environmental persistence. It was evident that we were heading towards a pest control strategy based on high inputs of synthetic chemicals as a sole means to tackle pests, weeds and diseases. The problem arose when we began noticing that most synthetic pesticides, and even alternatives to DDT such as dieldrin, are persistent organic pollutants that not only have a tendency to persist in the environment, but furthermore tend to biomagnify as they are passed along the food chain (Henderson, 2011). Workers, their families, bystanders, and consumers are all exposed to tolerable and occasionally dangerous levels of synthetic pesticides on a daily basis. The storage, usage, handling and disposal of these chemicals further promote the development of cancers and negatively influence reproduction or disrupt the endocrine system (CBC News, 2003). In addition, pesticide residues in food and drinking water can cause similar problems and affect an even greater number of people. The economic problems brought about by synthetic pesticide use are not nearly as evident. The demand for higher yields that were once granted by pesticide use still exists, and many farmers are feeling the pressures and dependency for a degree of control equal to or greater than that given by synthetic pesticides (Kennedy, 2011). External costs for health treatment, costs from illness related lack of work, loss in biodiversity and water treatment all contribute to a downward spiral of dependency that only creates a need for newer, stronger, and probably more expensive pesticide (Pimentel et al., 2011). It is clear that the demand for pesticide alternatives is great, and while some strategies do exist, the issue then becomes whether or not we can maintain food security worldwide with the inevitable decrease in yield that comes from more natural strategies for pest control.

The Solution While there are natural alternatives and sustainable farming practices already being used on a wide range of crops, they are not widely adopted. Instead of it being up to the farmer to employ more natural alternatives to synthetic pesticides, work needs to be done at all levels of agriculture from scientific and field research to awareness campaigns. The main objective is to redesign agricultural cropping systems instead of how to replace specific pesticides (Henderson, 2011). Production systems need to be holistic and sustainable, with a complete abandonment of toxic synthetic pesticides. There are many practical case studies that tell us pesticides are not necessary, especially to the extent they have been used in the past and in some areas are still being used (Huang et al., 2003). Therefore, in addition to reducing pesticide use presently, there needs to be more generation, innovation, and promotion of ecological alternatives to pesticide use.

Integrated Pest Management Gardeners, farmers and even municipalities are more frequently trying to reduce their reliance on chemical pesticides, opting instead for a concept called Integrated Pest Management (IPM). This strategy is an environmentally sensitive and effective approach to pest management that relies upon a few basic steps. IPM is not a single pest control method, but rather a combination of stages that include prevention, observation, and intervention (Henderson, 2011). IPM programs tend to use current information on the life cycles of pests and their interaction with the environment, and apply available pest control methods to manage pest damage by the most economical means possible, while posing the least hazard to people and the environment (EPA, 2011). The great thing about IPM is that it acts as a continuum, firstly by setting pest thresholds which aim to identify when action needs to be taken, then identifying which pests themselves are present, and then taking action to prevent pest threshold levels from increasing. Once monitoring, identification and action have taken place, IPM programs will reevaluate from step one to determine the proper method of control for maximum effectiveness and minimal risk (EPA, 2011). In addition, the same principles of IPM that are applied to large farms can be applied to your own garden.

Organic Alternatives & Applications Contrary to popular belief, organic landscaping or farming does not mean using natural pesticides. It means taking a sustainable, preventative and holistic approach to prevent weeds and unwanted pests from settling in the first place. Just as organic farmers have found that interspersing crops with different species slows down the spread of pest insects, and attract beneficials, the average consumer can do the same with their lawn or garden. (Baird & Cann, 2008). There are several simple strategies that can be employed by the everyday consumer that will greatly enhance the sustainability of your land, and contribute to a self-sufficient garden that requires little to no maintenance. For example, instead of bagging grass clippings after you mow the lawn, you could leave them there to act as a natural source of nutrient cycling, and the decomposing organic matter will acts as a food source. Taller grass also deters pests and weeds, and promotes vigorous growth – which when accompanied by a sharp mower blade will greatly reduce the incidence of pests and diseases, as torn grass from a dull mower blade makes the lawn more susceptible to disease (Henderson, 2011). It is also prudent for consumers to educate themselves on what is allowable for pest control in their municipality. For example, while many bans are currently in effect, the website for the City of Toronto has a list of acceptable products that can be used while adhering the pesticide bylaws. According to the website, products you can use may contain the following active ingredients; a soap, a mineral oil, silicon dioxide, Bt (Bacillus thuringiensis, nematodes, borax (boric acid or boracic acid), ferric phosphate, acetic acid, pyrethrum or pyrethrins, fatty acids, suplfur or corn gluten meal (Toronto Public Health, 2004).

Canadian Trends While the individual consumer shift from synthetic pesticides to natural alternatives is a step in the right direction, the actions of municipalities and cities will set the trend for everyone else to follow. It is becoming more and more common for municipalities in Canada to reduce their reliance on chemical pesticides, and move to Integrated Pest Management. Some part of Canada are taking it even further, for example many parks departments in Canada have been instructed to reduce the cosmetic use of pesticide on town property (CBC News, 2003). Nova Scotia even tried to make history by becoming the first Canadian municipality to phase out all pesticides, a goal which they failed to accomplish by 2005 (Kennedy, 2011). If you live in Canada, chances are that you require written permission from your neighbor in order to spray near their property line. Even the landscapers at the lieutenant-governors residence do not use chemicals, they are using insecticidal sprays made of soap, garlic and rhubarb, and are fertilizing with manure and compost (Kennedy, 2011). In Windsor, the parks department has resorted to using a focused stream of hot steam to kill unwanted weeds along fence lines. So far, they have succeeded in reducing their pesticide use by 50% (Kennedy, 2011). In the future, McGill University researchers hope to release a fungus that will help kill dandelions with 14 days (Anderson, 2011). Also, Chinese researchers are investigating the effects of genetically engineered Bt cotton crops on reducing pesticide use (Huang et al., 2003).

Economic Effects of Reduced Pesticide Use While much progress has been made in the field of pesticide use and application, several problems arise in the aftermath of pesticide bans or phasing out. Several experts, including Dr. Ivan Kennedy, Professor of Environmental and Agricultural Chemistry, warn that pesticide bans will threaten world food security. These threats stem from the aftermath of pesticide bans and even the gradual phasing out of pesticide use over several years. As discussed earlier, the high food demand will not decrease as crop yields decrease. This will put the food supplies for millions of people and the crops for millions of farmers at risk. In addition, the cost of foods cold rise dramatically as pesticide alternatives can be much more expensive and the work involved in supplying the food demand worldwide is costly. Kennedy states, "The POPRC (Persistent Organic Pollutants Review Committee) has relied on cherry-picking the data, and testing in unrepresentative laboratory conditions, to classify endosulfan as a Persistent Organic Pollutant. Our recent review shows that POPRC has failed to establish that endosulfan meets their criteria as a POP. Taking such an extreme precautionary approach towards important tools for agriculture, as advocated by the green movement, places the global food security of billions of people at risk." Kennedy believes that the answer lies within a phase out period of at least 10 years, to help the current main producers and users of synthetic pesticides, particularly in India and China, the time to research better alternatives.

CONCLUSION The history of pesticide use has been riddled with controversy, from adverse health effects to economic stresses. While it would be better for the environment if all pesticides were banned, it would cause such an abrupt change in the global dynamic of agriculture that chaos would ensue. It is estimated that if this were to happen in the U.S., 132,000 people would lose their jobs, food aid programs to developing countries would slow, and worldwide hunger would increase (Bell, 2011). Additionally, the ever increasing demand for food would provoke farmers to cultivate more land which in turn would destroy habitats, and countries with less strict or fewer regulations may increase pesticide use to make up for a reduction in exports from developed countries (Bell, 2011). While the future is uncertain, many people, organizations, municipalities, governments and corporations are working towards a more environmentally friendly and sustainable approach to pest management. With the increasing presence of environmentally compatible chemicals coming on the market, there is also a good chance that chemicals will be present in the pest management industry in the foreseeable future. This is particularly true when we look at the growing proportion of reduced-risk pesticides being registered with the EPA, and since competitive alternatives are not yet readily available. For the time being, however, environmentally friendly options do exist, even for your household. There are organic pesticides available on the market, as well as home-made solutions that with a little research can be just as effective as synthetic pesticides. We do not have to wait for the effects of tomorrow to make a change today. If worse comes to worst, we can always let nature have its course – it seems to figure out problems just fine without human intervention.

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References: Anderson, M. (2011, June 7). Pesticide bans should be scientific and done by the Feds. The Vancouver Sun; Sect. A:1. Anonymous. (2001, July 20). B.C. Pesticide ban would be a win for health and business. Revelstoke Times Review; Pg. 1. Baird, C., & Cann, M. (2008). Environmental Chemistry. (4th ed.). New York (NY): W.H Freeman and Company. Bell, W. (2011, July 22). Benifiting from a pesticide ban. Prince George Citizen; Pg. 6. CBC News. (2003). In Depth: Pesticide alternatives. Retrieved July 30th, 2011, from http://www.cbc.ca/news/background/pesticides/alternatives.html Cooper, K., & McClenaghan, T DDT. (n.d.). In Wikipedia. Retrieved July 30th, 2011, from http://en.wikipedia.org/wiki/Ddt [->0] Environmental Protection Agency Roberts, D.R., Manguin, S., Mouchet, J. (2000). DDT house spraying and re-emerging malaria. The Lancet, 356(9226), 330-332. Sibley, John. (1997). State committee Urges a Ban on DDT and Related Pesticides. The New York Times, 50(1), 6. Toronto Public Health. (2004). Pesticide Free: A Guide to Natural Lawn and Garden Care. Retrieved July 28th, 2011, from the City of Toronto Public Health site: http://www.toronto.ca/health/pesticides/pdf/natural_lawn_guide.pdf UNIDO