Review of Literature

   Over the past 50 years, pesticides have become a blessing for the world’s growing population but also a toxic problem in the environment. They can negatively affect many factors of the environment, even humans. For my project, I will be focusing on how pesticides impact soil and how those impacts affect plants and animals that interact with the soil. This is important because I think it may almost be to the point of a crisis that not many people think or know about and I want to educate my readers and make them aware of things they have never thought of. The similarities in sources that I found fell into a few categories: the food chain, soil loss, Monsanto's 'Roundup,' microbial communities, groundwater, and there we also a few miscellaneous sources.

   Pesticides entering the food chain are a real concern for many people today. I have found a few sources that speak to this topic including Rachel Carson in her book Silent Spring written in 1962. Even though Carson wrote this book over 50 years ago, it is still relevant today and provides information about how pesticides can enter the food chain and effect animals and humans. I will use this source to research the links between soil and the food chain. In Deborah B. Vineela’s study “The Degradation of the Herbicide Bromoxynil and Its Impact on Bacterial Diversity in a Top Soil” the idea of pesticides entering the food chain is talked about again with frightening facts. For example, 1% of pesticides reach the target organism and the other 99% can enter the food chain and harm human beings. The pesticides can harm us but they can also harm life in the soil which is just as concerning. I will use this source to pull quotations from. Other scientists like Md. Wasim Atkar and his colleagues say in their study “Impact of Pesticides Use in Agriculture: Their Benefits and Hazards” that pesticides effect many factors of the environment including soil, food, humans, water. Although pesticides may seem like a good options because they aren’t very time consuming, they come at the cost of the environment. There is a section specifically on soil in the article that seems easy to read and understand and at the same time is very important. Many sources are cited so that will be a good place to look if I'm looking for any more information. I also like how the benefits of pesticides are also talked about.

   Soil loss is something else that I’m worried about due to pesticides. In the 2009 documentary Dirt!, it is brought to viewers’ attention the importance of fertile soil and how we are losing it due to the practices of the modern world (ex: mining, pesticides). It talks about how the fate of soil is in our hands. I think this will be a good source to pull quotes from because documentaries about environmental problems usually use a lot of emotional appeal and I want to appeal to my readers and make them want to make a difference. Ward Chesworth also states the danger of losing soil in his article, “Voices: Peak Soil: Does Civilization Have a Future?” on the website Earth: The Sciences Behind the Headlines. He says that there is a ‘peak’ everything including peak soil which supposedly happened 10 millennia ago. This article explains that farming is a very destructive practice and that losing soil is a real danger to our growing population. Although this doesn’t have anything to do with pesticides, I will probably use ideas from this article to back up the idea of how important it is to have good soil. George Antonious and his colleagues briefly touched on the subject of losing soil as well, in the introduction to their study, “Sustainable Soil Management Practices and Quality of Potato Grown on Erodible Lands.” "Land productivity can decline when top soil is lost." Top soil, which can be lost due to pesticides, is important in the biological system cycles so its crucial to keep it healthy. The point of this study was to “quantify the impact of three soil management practices on quantity of potato produced on erodible land, ... to evaluate the impact of pyrethrin and azadirachtin insecticides on potato tuber quality and … to assess the impact of yard waste compost the the chemical composition of potato tubers.” I will be looking at this study for the insecticide conclusions.

   Another topic that kept popping up through my research was Monsanto's Roundup herbicide. John Peterson wrote an article Down in the Dirt, about his organic rented farmland was sprayed with Roundup and how he recovered the land with cover crops so it was suitable for growing vegetables again. I want to use this article because it tells the story of a real farmer and I may be able to pull concerns that he has and talk about them in my paper. Tom Philpott in his 2011 article in Mother Jones USDA Scientists: Monsanto's Roundup Herbicide Damages Soil, talks about how Monsanto's Roundup may be damaging soil which could have very negative effects because their fields take up millions of square miles in America. Even though the USDA knows that Roundup is dangerous, they keep approving it. Plants, animals, and soil are all effected. I will hopefully be talking a bit about Monsanto in my paper and I will use this source to refer back to. Philpott also has another article in Mother Jones from 2013 Talk Dirt to Me which highlights a farmer who doesn't till and uses cover crops to keep his soil healthy. The farmer's soil is more drought and flood resistant when compared with soil from conventional farming Although he is not full on organic, he has reduced the amount of pesticides he uses. I may use this source to compare and contrast soil with pesticides in it and soil with less. Pesticides are hardly mentioned in this paper so it may come in little handy.

   Microbial communities were the biggest reoccurring theme throughout my study of sources. Stephanie Strom's article on The New York Times website titled Misgivings About How a Weed Killer Affects the Soil, talks about real concerns from real farmers. Farmers think that pesticides affect microbial processes but Monsanto says that there is no real evidence. There is talk on the difference between soils. If I use this source, it will be to use those real concerns for an argument or for evidence. Siad Fantroussi and his colleagues did a study and published it in a 1999 issue of American Society for Microbiology called Effect of Penylurea Herbicides on Soil Microbial Communities Estimated by Analysis of 16S rRNA Gene Fingerprints and Community-Level Physiology Profiles. It was done on the effects of the three herbicides, diuron, linuron, and chlorotoluron on the microbial communities in the soil. The result was that they are affected by long-term pesticide use. Since it is a study, there are many small details and long names that are hard to sift through. I may just use the fact that a study was done and what the results were. Yet another study was done by J Baxter and S.P. Cummings which you can find in a 2008 issue of Journal of Applied Microbiology called The Degradation of the Herbicide Bromoxynil and Its Impact on Bacterial Diversity in a Top Soil. This study shows that bromoxynil affects soil bacteria which in turn affects the rate of degradation and persistence of bromoxynil. Degradation rates were lower and it increased the persistence. All these studies are great to have as sources because they are scientific proof that will hopefully win my readers over to my side of the issue. In the article Pesticide Effects on Bacterial Diversity in Agricultural Soils- a Review, Kaare Johnsen and colleagues think that new ways to test pesticides on bacteria should be formed. There should be protocols for it. They should only be toxic to target organisms, not leach into ground water, and be biodegradable. Those would be good solutions to fix the issue. I may use this source if I write about solutions to the problem. British Columbia's web page has a section called Environmental Fate which is a huge overview of pesticide effects. It doesn’t go into much depth but in the same sense that is what makes it a good source to read. You get a lot of information quickly. It talks about how pesticides can get into the surrounding environment, what happens when they get there, and how they break down. Volatilization, spray drift, runoff, leaching, absorption, crop removal, breakdown, photodegradation, microbial breakdown, and chemical breakdown are topics that are discussed.

   Groundwater was also mentioned a few times, like in Alain Hilderbrandt and colleagues study in a 2007 issue of Analytical and Bioanalytical Chemistry Assessment of Priority Pesticides, Degradations Products, and Pesticide Adjuvants in Groundwater and Top Soil from Agricultural Areas of the Ebro River Basin. It said that when pesticides are in the soil, they can leach into and contaminate groundwater. This is concerning because it may lower the quality of drinking water. Gas chromatography-mass spectrum was used for finding 30 widely used pesticides with the goal of assessing their impact on agricultural soil and groundwater. I don’t think I will be using this source anymore. This source, though, gave me the idea that I need to narrow the word 'soil' in my project to 'agricultural soil.' Francesco Mazzieriand his colleagues also mentioned groundwater in their study Stabilisation/Solidification of Soils Contaminated by Chlorinated Pesticides published in Chemistry and Ecology from in 2007. This is a study done on how the addition of soil and sediment with activated carbon is beneficial when cleaning up soil contaminated by chlorinated pesticides. These pesticides were leaching from the soil into the groundwater and moving through the environment. The technique used does not require soil excavation and is fairly cheap in cost. I will use this source to talk about pesticides move from soil to groundwater or how to solve the issue.

   Some miscellaneous sources that I found include William S. Curran's Persistence of Herbicides in Soil which you can find on Pen State's College of Agricultural Science page. He wrote about how soil factors, climatic condition, and herbicidal properties affect how long herbicides will stay in the soil. The factors interact with each other very closely. This will be good to use for a voice of authority and scientific facts or evidence. The 2009 documentary Vanishing of the Bees directed by George Langworthy and Maryam Henien was another one that didn't fit into a category. This documentary is about how bees have begun to vanish around the world. Without bees, life on Earth would not be the same. Pesticides are a targeted cause in this film for why bees have been disappearing. Bees are connected to plants which are connected to the soil so I may find some information on the indirect effects on pesticides on soil. Thomas R. Dunlap's DDT, Silent Spring, and the Rise of Environmentalism are a collection of readings is about the books named in the title. The texts all relate to pesticides. There is good background information that I could use in my introduction to introduce the main points about pesticides and how they came to be. I will skim the book and look for sections of importance. Susan E. Crow and her colleagues did a study Sources of Plant-Derived Carbon and Stability of Organic Matter in Soil: Implications for Global Change published in a 2009 issue of Global Change Biology which didn't fit into a category either. It was about how plant litter affects soil. They tested two different types of forests: aggrading deciduous and old-growth coniferous. Plant litter bring nutrients to the soil that plants can then use to help them grow (with pesticides, it kills all the good bacteria and fungi). I will use this source to study how to bring nutrients back into the soil. Maybe in my conclusion or and ending paragraph, I can state some solutions to the issue.