The Impact of Pesticides on Humans

by Elizabeth Young

Introduction

As the Green Revolution grew, so too did the use of new technologies, specifically the use of synthetic chemicals on crops.  One staple of the Green Revolution has been the development and use of pesticides.  “A pesticide is defined as any substances intended for preventing, destroying, or controlling any pest, including vectors of human or animal diseases, unwanted species of plants or animals that cause harm during the production, processing, storage, transport, or marketing of food, agricultural commodities, wood and wood products, or animal feedstuffs, or which may be administered to animals for the control of insects, arachnids, or other pests in or on their bodies” (Anwar 801).

The use of pesticides, however, is controversial.  While they are used to, essentially, keep the wild out of farms, the toxins affect more than the environment, the ecosystem, and the organisms.  Pesticides are also ingested, breathed in, and absorbed through the skin by humans.  Pesticides are also the number one tool of farmers in ensuring that they can grow a crop and make a profit.  Most fruits and vegetables that touch the dinner table have come in contact with pesticides.  Even those processed can still maintain elements of those pesticides.  Due to the seemingly unavoidable chemicals being used in such high numbers, it has become a controversial Green Revolution invention.  One side argues that pesticides are detrimental to human health and that pesticides cause more harm than good, including Wargo and Bolognesi.  The opposing side, like in Chrop Chemophobia by Jon Entine, argues that any negative affects are far outweighed by the positive effects.  Those positive affects are the amount of food produced due to the use of pesticides and the lowered rates of disease spread by insects and contaminated food.

Neither disagree that pesticides can be harmful to humans, but they disagree on how harmful and the level of risk.   Harold Zeliger even states: “All pesticides are toxic to humans” (173).  It is the strength of the pesticide, the amount of exposure, and other factors that play into the possibility of harm on the human body or population.  The toxicity is also influenced by the how long the pesticide last after it is applied.  Some pesticides last longer than others, for example DDT can still be found in the environment today (National Toxicology Program 144).

Charles Mann best describes the role of pesticides: “The Green Revolution of the 1950s and 1960s introduced herbicides, pesticides, and advanced agricultural technologies to the developing world–rescuing hundreds of millions of people from malnutrition and starvation and transforming low-yield, labor-intensive farming into the productive, high-tech industry it is today (Mann p1043).”  Since the Green Revolution, the use of pesticides has increased exponentially.   The use of pesticides worldwide has reached 2.6 million metric tons and 85% of that amount was used in agriculture (Tisdell and Wilson).  On top of that, the concentration and amount has also increased over the years.   Pesticides are also used beyond agricultural use.  “[Pesticides] are used worldwide to protect crops, food, and animals from undesired contaminations, to control vectoborne diseases, to keep ponds, lakes, and water reservoir free of undesired algae and water grasses, and to clear roadside weeds, trees, and brushes” (Bolognesi 438).

Besides pesticides, there are also fungicides and insecticides.  Insecticides are the most frequently used in developing countries and are primarily organochlorine, organophosphorous, carbamate, and pyrethroid compounds as well as some inorganic compounds (Anwar 101).  Different chemicals have different affects.  Some chemicals work as a barrier- they discourage bugs or animals from wanting to be near where it was sprayed.  Others kill on contact or when eaten.  Another difference is that some are synthetic whereas other can be naturally found in nature.  One frightening pesticide is organophosphates, which was originally designed for nerve warfare and is now widely used in pesticides (Schettler 124).

Effect on Body

Due to the amount it is used, it is important to understand the risks involved in using chemicals on human food sources.  Unfortunately there are more than 70,000 separate pesticides in the market as of 2009 (Wargo 157).  The amount on the market and the number of different chemicals makes tracking the dangers or supposed risks of these chemicals difficult.  The government even has special task forces that work primarily in measuring pesticides.  The FDA, EPA, and the Food Safety and Inspection Service of the US Department of Agriculture, are responsible for monitoring levels of pesticides and ensuring that the residue will not pose a danger to health (Federal Department of Agriculture).  The Federal Department of Agriculture also highly recommends washing all fruits and vegetables before consumption to wash off any remaining residue.

The average dietary adult out of 120,000 people is exposed to 11 contaminates by the U.S. Food and Drug Administration Total Diet Study.  These eleven include “four heavy metals (arsenic cadmium, lead, mercury,) three organophosphate pesticides (chlorpyrifos, diazon, malathion), and four organochlorine pesticides (dieldrin, p,p’-DDE, lindane, heptacholar epoxide” all with varying levels of exposure (MacIntosh 202).  Lab studies have concluded however that large amounts can have negative affects on the human body and that it can be found present in years after exposure.  There are also multiple ways that humans can be exposed to the toxins in pesticides: skin absorption, inhalation, and ingestion are the most common (Schettler 113).  Those who are more exposed are at a higher risk.  In fact, pesticide poisoning occurs in 18.2 agricultural workers out of 100,000 in developing countries (Bolognesi 349).  It also poisons 7.4 million children, also primarily in developing countries (350).

Pesticides have caused immune suppression in humans not only in developing countries, but encompassing the globe (Acquavella).  Pesticides can also cause a degenerative disorder of the nervous system in the form of Parkinson’s and other diseases (Xu).  There is evidence-linking exposure to pesticides to an “elevated rate of chronic diseases such as different types of cancers, diabetes, neurodegenerative disorders like Parkinson, Alzheimer, and amyotrophic lateral sclerosis, birth defects, and reproductive disorders” (Mostafalou 157).  Pesticide exposure has also been linked to parental infertility, birth defects, childhood cancers, spermatotoxitity, retarded intrauterine growth, and chromosome damage (Schettler 123).   There were increased miscarriages in grape gardens in Indian in couples exposed to pesticides and in Columbia there were increased miscarriages:

An average of 23 deaths occur each year with pesticides as the underlying cause of death, most due to suicidal ingestions. An average of 130,136 calls to poison control centers were reported from 2006 to 2010, with an average of 20,116 cases (17.8%) treated in health care facilities annually. AHQR reported an annual average of 7385 emergency room visits during 2006 to 2008, and 1419 annual hospitalizations during 2005 to 2009.

(Langley 300)

Insecticide exposure has also been associated with cardiovascular, nervous system, sensory, and respiratory disorders (Anwar 801).  Wagida Anwar also goes on to discuss reports of skin disorders, headache, and nausea.  Anwar discusses that workers exposed to organochlorine, organophosphorous, and carbamate insecticides were later observed to having abnormal electroencephalograms.  Electroencephalograms are recordings of electrical activity of the scalp and the brain’s spontaneous electrical activity.

Role of Pesticides

So, if the dangers of pesticides are so numerous, why are they still being used?  Mayer depicts it as the following: “Nutrition is one area where figures can be put on human needs.  The techniques of the Green Revolution have enormously increased the potential to fulfill those needs.”  He even goes further in saying in order to improve the food crisis in nations’ with need that there should be, along with other things, “greater availability of nitrogen, potash, and phosphate fertilizers and of pesticides, insecticides, and rodenticides (Mayer p707).

Another argument of the advocates of pesticides is the risk vs. hazard (Entine 9).  Now, because the fear of harm caused by pesticides, there are more tests than ever on the harms of pesticides.  The problem with these tests is that they moved from “risk-based” to “hazard-based.”  Risk-based is based on the application of pesticides in the real world, while hazard-based are on laboratory data.  “Do we really want to be telling the hungry of the world to persist on a diet of precaution?” (9).   On top of that, the testing is usually based on higher dosages than the average human would come in contact with.

Pesticides have played their role in the Green Revolution by helping to solve the world’s hunger crisis as well as making crops less difficult to grow in certain environments.  “In order to maintain healthy crops, farmers fight a constant battle against insects, fungi, and plant diseases, as well as weeds… Advanced modern agricultural chemical technology has helped prevent infectious diseases and enhanced crop yields.  Pesticides and herbicides protect crops against weeds, insects, and fungus. They are one of the drivers of the Green Revolution, which has dramatically cut world hunger in the past sixty years” (Entine 3).  Pesticides also lower the risk of contamination from bugs or animals.

Besides insuring a good crop, pesticides have also almost completely eradicated malaria where they were applied.  According to Entine, Americans no longer need to worry about malaria because of the use of pesticides.  Unfortunately, malaria still has killed, is killing, and will continue to kill humans today.  In the 20th century alone, over 100 million people were killed by malaria (Wargo 174).  On top of the deaths in the 20th century, there continues to be a death rate of a million people every year (174).  America was able to lower the death rates to numbers practically inconsequential.  Other areas are not so fortunate.  Wargo even states that the biggest reason millions die of malaria today is money.  Where poverty is present, there is a higher risk of dying from this preventable disease and others like it.  In Africa, 90% of deaths from disease worldwide occur.  If these pesticides can be applied to areas in need, like in parts of Africa and South America, there can be an eradication of a disease killing millions. Money is also a reason that pesticides are relied on.  Pesticides are expensive, but also a cheaper recourse than using other methods.  This means that poorer nations have limited access while other nations have a heavy reliance.   The other issue besides money is the pesticides being used.  In the 1950s, the most commonly used pesticide to kill the mosquitos that spread malaria was DDT (175).  DDT is an extremely controversial poison that scientists today still argue over the hazard.

DDT

DDT is Dichlorodiphenyltrichloroethane.  The U.S. Department of Health and Human Services’ Report on Carcinogen Profiles declared that Dichlorodiphenyltrichloroethane, or DDT, is “reasonably anticipated to be a human carcinogen” (National Toxicology Program 143).  DDT was introduced in the United States in 1939 as a pesticide.  Since then it had been one of the most widely used insecticide in the world (144).  The United Sates banned DDT in 1972, but is still persistent in the environment today.   DDT did not start out for public health; instead, DDT was created to control clothes moths (Entine 97).  Later in World War II, it was used to control lice that spread typhus.  DDT also last longer when sprayed- up to one year compared to two weeks in previous pesticides (97).  While some argue over the toxicity of DDT, it is extremely useful in acting as a barrier to mosquitos that could spread malaria (98).  Due to the laws against DDT, it is no longer allowed to be used in America and other countries (104).  This has lead to a price rise- keeping poorer nations from being able to afford it in the war against malaria.

Conclusion

Pesticides are harmful to the environment and potentially harmful to humans.  They remain in the environment years after being sprayed.  The government even warns against eating agricultural goods without washing them first.  In such a large market, it is difficult to regulate and almost impossible to warn the public about.  Many pesticides poison, cause cancers and diseases, and even kill those who come in contact with it.  On the other hand, pesticides have helped feed and clothe and insure the health of more than they have harmed.  These chemicals have helped aid the world hunger crisis as well as practically eliminate the infection and spread of deadly diseases such as malaria where applied.  Pesticides were one of the pillars of the Green Revolution and have more possibilities than can be imagined.  However, one of the most important aspects of agricultural science is that it must evolve.  Much as the science of the healing arts has evolved from blood-letting to the modern miracles of today, so too have agricultural sciences- especially pesticides- evolved and will continue to grow and change.

If science can find a less harmful and less expensive chemical or treatment, millions more will be fed.  Even just the spread of funding can for new technologies can aide countries in need as well as give the people a way to make a living.  Though there is a possibility of the pests becoming resilient of the chemicals, there is a higher probability that science will surpass that and more.  There will always be ways to improve the science of agriculture.  Some may fear the dangers, but the worst has past.  Now is the time to push forward to use our new information about the dangers to develop new methods and hopefully, make the world a better place to live. Much as the book Crop Chemophobia implies, it is almost more dangerous to eliminate the use of pesticides for human health since this science has many possibilities.  Overall, pesticides are a technology that requires monitoring and regulation, but can be beneficial today and in the future.

 

Works Cited

Acquavella, John. “A Critique of the World Resources Institute’s Report “Pesticides and the Immune System: The Public Health Risks”” Environmental Health Perspectives 106.2 (1998): n. pag. JSTOR. Web. 4 Apr. 2013.

Anwar, Wagida A. “Biomarkers of Human Exposure to Pesticides.” Environmental Health Perspectives 105 (1997): 801-06.

Bolognesi, C., and F. D. Merlo. “Pesticides: Human Health Effects.” Encyclopedia of Environmental Health (2011): 438-53.

Entine, Jon. Crop Chemophobia: Will Precaution Kill the Green Revolution? Washington, D.C.: AEI, 2011. Print.

Guillette, Louis, Jr., and Taisen Iguchi. “Life in a Contaminated World.” Science 337 (2012): 1614-615. JSTOR. Web. 24 Apr. 2013.

Landrigan, Philip. “Pesticides and Inner-City Children: Exposures, Risks, and Prevention.” Environmental Health Perspectives 107.3 (1999): n. pag. JSTOR. Web. 4 Apr. 2013

Langley, Ricky. “Human Exposure to Pesticides in the United States.” Journal of Agromedicine 17.300 (2012): n. pag. Print.

MacIntosh, David, Haluk Ozkaynak, P. B. Ryan, John D. Spengler, and Ling-hui Tsai. “Dietary Exposures to Selected Metals and Pesticides.” Environmental Health Perspectives 104.2 (1996): 202-09. Print.

Mann, Charles. “Reseeding the Green Revolution.” Science, New Sciences 277.5329 (1997): 1038-043. JSTOR. Web. 11 Apr. 2013.

Mayer, J. “In Reply: Preventing Famine.” Science 227.4692 (1985): 707. Print.

Mostafalou, Sara, and Mohammad Abdollahi. “Pesticides and Human Chronic Diseases: Evidences, Mechanisms, and Perspectives.” Toxicology and Applied Pharmacology 288.2 (2013): 157-77. Print.

National Toxicology Program. “Dichlorodiphenyltrichloroethane.” National Institute of Environmental Health Sciences 12 (2000): 143-45.

“Pesticide.” Pesticide Q&A. U.S. Department of Health and Human Services, June 1993. Web. 30 Apr. 2013.

Schettler, Ted. Generations at Risk: Reproductive Health and the Environment. Cambridge, MA: MIT, 1999.

Wargo, John. Green Intelligence: Creating Environments That Protect Human Health. New Haven, CT: Yale UP, 2009. Print.

Wharton, Clifton, Jr. “The Green Revolution: Cornucopia or Pandora’s Box?” Foreign Affairs 47.3 (1969): 464-76. JSTOR. Web. 11 Apr. 2013.

Xu, Xiaohui. “Parkinsonism and Occupational Exposure to Pesticides.” Associations of Serum Concentrations of Organochlorine Pesticides with Breast Cancer and Prostate Cancer in U.S. Adults 118.1 (2010): n. pag. Web. 4 Apr. 2013.

Zeliger, Harold I. Human Toxicology of Chemical Mixtures: Toxic Consequences beyond the Impact of One-component Product and Environmental Exposures. 2nd ed. Norwich, NY: William Andrew Publ., 2011.

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