envs 3020: Pesticides Risks, Benefits, and Discovery - PDF

1 - Pesticides Risks and Benefits January 6, 2025 9:35 AM envs 3020 Page 1 envs 3020 Page 2  Plants continuing to evolve to evade pests, pests evolving to get past new defences. Primary metabolites - needed for...

1 - Pesticides Risks and Benefits January 6, 2025 9:35 AM envs 3020 Page 1 envs 3020 Page 2  Plants continuing to evolve to evade pests, pests evolving to get past new defences. Primary metabolites - needed for respiration and to live Secondary metabolites - usually chemicals used to protect, things that make the plant smell/taste bad Pests evolving to get past secondary metabolites envs 3020 Page 3  Allelopathy - plant releases chemical into the soil to alter soil and impact other species ability to grow in that area envs 3020 Page 4 envs 3020 Page 5 envs 3020 Page 6 envs 3020 Page 7  Impact on protecting public health envs 3020 Page 8 envs 3020 Page 9 envs 3020 Page 10 envs 3020 Page 11 envs 3020 Page 12 envs 3020 Page 13 envs 3020 Page 14 envs 3020 Page 15  Insecticides sprayed into storm drains to prevent mosquitoes in stagnant water. *pesticides can be used to prevent vector born disease* DDT in paint in african countries to prevent mosquitoes envs 3020 Page 16  "perfect" products require the sue of pesticides and insecticides to look that way Plants produce a lot of secondary metabolites that act as pesticides. Chaconine and solanine produced by potatoes to naturally prevent pests. High levels of Glycoalkaloids can cause birth defects. Okra toxin A - produced by fungus and grows on wheat. The toxin is a powerful renocarcinogen (can cause kidney cancer) Screw up with DDT is what gives people bad impression of pesticides. Companies who produced DDT tried to cover up the impact of DDT killing birds. Companies now will weigh the risk of a product and decide whether or not to release it or will stop producing a chemical because of its impact. Agent orange - a defoliant used in the Vietnam war to defoliate the trees and see what was going on. This led to birth defects in the future. 24D and 245T were the active ingredients. On their own these two ingredients don’t form birth defects but a biproduct of the two being mixed resulted in bi-product (dioxant) that was the cause of the birth defects. 245T used to be used by Ontario hydro to prevent trees touching power lines. Cheaper than paying for the labour of doing it manually envs 3020 Page 17  Urbanization taking up arable land. In places like brazil or africa, to increase arable land they are converting forests and other natural habitats into farm land. Exotic plants being brought over and spreading rapidly and take up a lot of water. Phragmites can only be tamed with a systemic herbicide. This means that once the herbicide is sprayed on the plant it will spread throughout the entire plant. Having an issue near lake eerie with phragmites and getting rid of it. envs 3020 Page 18  Europe has become very conservative with their use of pesticides. A lot of produce from europe comes from other countries. They are exporting their pesticide use to other countries because they don’t want to use it. Social and moral playing into perception of pesticides envs 3020 Page 19 envs 3020 Page 20  *will be on midterm* Lower observability drives up risk perception (i.e. GMO food). Less controllability drives up risk perception. envs 3020 Page 21  Distrust in companies producing pesticides Government bc they mandate use envs 3020 Page 22  Bring the public in line with what the actual risk is Risk communicator thinking of intensity of conflict and the degree of complexity. More complex issues are harder to communicate. High intensity is very hard to communicate. World views and values are the hardest to discuss (war in isreal and gaza). Lower the knowledge needed, the easier it is to communicate the issue. Not reliant on factual data. First two there isn't much control over. The third can be learned. Credibility can be fostered envs 3020 Page 23  Some don't want to dumb it down because information will be lost They can communicate but don't have the knowledge. Best to bring best of both categories to communicate envs 3020 Page 24  Recent issues with vaccines and distrust. Distrust in government regulation even through making tougher regulations and guidelines for pesticide use. We don’t have to worries about where food is going to come from (for the most part) so we then begin to worry about smaller problems. Our perception of risk changes. Subsistence farmers in Africa having different perceptions of risk than someone in Guelph. Offering pesticides to the subsistence farmer, they would be willing to take the risk to increase their yield. People here worried about whether or not food is organic over anything else. Benefits less interesting to read, especially mass media. Industries are interested but it is difficult to communicate to large population. Way easier to put the bullshit out there but really hard to ring it back in to spread truthful information. Portion of the public thinks we're just greedy. Industries responsible for the distrust that has occurred from previous controversy and cover ups (DDT, agent orange, etc.) Trying to invest in the research and programs. envs 3020 Page 25 2 - Pesticide Discovery January 17, 2025 9:29 AM envs 3020 Page 26 envs 3020 Page 27 envs 3020 Page 28  Doesn't take much for them to damage tissue. Bordeaux mixture, usually copper sulfate and lime. Used to protect grape vines from fungus. Don't break down into the environment. Keep adding up every year and get washed into the soil causing build up and eventual toxicity. Arsenic build up. Sodium chlorate build up. *non target toxicity biggest problem Could become toxic to plants you're trying to grow. corrosive envs 3020 Page 29  Bi-products of the petrochemical industries. Starting to synthesize molecules. DDT synthesized in 1874 and was not seen as useful. Can mimic plant hormone which can be detrimental to plant. Discovery of organophosphate insecticides. Researching for chemical warfare. Parathion is the first one that was developed while working on nerve gas. Causes disruption of breathing. Systemic insecticides are good because they spread through out the plant. Non-systemic insecticides will only protect what they cover. envs 3020 Page 30  Post emergent can be applied after the crop has germinated. Previously you could spray before to kill any weeds so crop could try and out compete them. Glyphosate has to get on the above ground tissue of the plant or else it will bond to the clay. Some effect only monocots like grasses and it will leave the dicots alone. Some pesticides move through the phloem and others move through the xylem with water. Fosetyl-al can move through both the xylem and phloem. Rotenone can be used in organic ag. And works on fish if you want to get rid of a fish species. Issues with plant extracts is that they are very good in the plant but degrade very quicky in the environment. Very sensitive to UV which breaks them down. Bio-rational synthesis: some organic chemists discovered molecules already in nature and tried to synthesize them to make them better. Avermectins can be used as a general antibiotic and came from soil bacteria. envs 3020 Page 31  Biopesticides are biological pesticides, an actual living thing. Bt is a bacteria and it very toxic to Lepidopteran (butterflies and moths). Very toxic to caterpillars. Prevents reproduction and causing major damage. In the digestive tract, because of the pH and conditions the spore will germinate and activate. The toxin binds to the epithelium and pokes a hole in the digestive tract. envs 3020 Page 32  Modifying crops to be resistant to glyphosate because it’s a very broad spectrum pesticide. Plants can be modified to produce insecticides (Bt corn). Wont leech into groundwater envs 3020 Page 33  How toxic is it to the pest? How toxic is it to non-target organisms? Does it break down really quicky? Variety of crops and pests it can be used on? Is it possible to produce in large quantities? envs 3020 Page 34  Checking if its mutagenic to bacteria. Teratogenic? (birth defects) Feeding chemical to animals and see what their body does with it. Most mammals digest quickly. Reproduction most difficult test. envs 3020 Page 35  Volatiltiy - potential to move into gas phase Problem b/c of inhalation, air pollution, non-target populations and ecosystems, blow into neighboring field envs 3020 Page 36 envs 3020 Page 37  Huge resources, lots of money. Large companies buying up smaller companies. Older companies survive Will buy companies that made a really good product for the patent and the product. Big mergers have to be approved by the government to avoid monopolies. When dao and dupont merged, dao had to divert their fungicide businesses and sell it in worries of a monopoly. envs 3020 Page 38 3 - Pesticide Uses January 22, 2025 9:29 AM envs 3020 Page 39  OPs - organophosphate insecticide Growth regulators mimic an insect hormone, so it messes up the growth progress of the insect, specifically in the early stages Survey when adults are coming out. Understand biology of pests IPM better for grower by saving money on product and better for enivronment envs 3020 Page 40  Harder to survey but envionmental conditions can give more potential for specific disease Poor heavily reliant on potatoes for food. In ireland other crops like wheat were being exported by the British envs 3020 Page 41  Because they were only growing very few varieties in Europe, it caused the fungus to spread easier. Not as impactful in South America because they grew more varieties and for a longer time envs 3020 Page 42  The fruiting body emerges from the leaf and spores and released. The wind disperses the spores and tries to penetrate and infect the leaf. Reproduce in leaf tissue. Releases all kinds of proteins that damages the tissues and absorb the nutrients. Leads to lesions on the plant. Fusaric acid helps break down the plants tissues which helps the fungus spread. envs 3020 Page 43  Can bring other fungus or bacteria with them. Weeds are so successful because of their ability to reproduce envs 3020 Page 44  Weeds out compete young crops and grow faster, which shades the seedling. Atrazine can be used post emergence. Corn plants arent very sensitive but the weeds are. Corn belt has heavy use of atrazine. Being replaced by GMO corn. Issue with pre-emergent is that the young plant doesn't have as much of a head start. Post emergent is ideal because it helps the plant more. *pre and post emergent pesticides and have some examples. envs 3020 Page 45 envs 3020 Page 46  Insecticides don't work on mollusks Huge public health issues - not so much in north america, mostly in Africa Carry a lot of disease Molluscicides used to deal with mollusks Using insecticides to get rid of insects can increase the population of mollusks Rodents and rats are one of the most damaging Rodenticides to deal with them Sea lamprey has expanded in the great lakes impacting trout and other species. Attach themselves to the fish and feed off of it. Control program for sea lamprey to keep the population down by using lampricides. Target juvenile lamprey envs 3020 Page 47  Pests in stored grain: use a fumigant envs 3020 Page 48 envs 3020 Page 49  2,4-D top use in homes is because it is selective of broad leaf weeds. Glyphosate is broad spectrum and would kill the entire lawn. Ban in ontario on using pesticides for cosmetic use. envs 3020 Page 50  Gravel at base of transformer towers to stop grass and soil from forming and good drainage. Grass and soil has high voltages. Chlorothalonil used for preserving wood. Less use because of broad spectrum toxicity envs 3020 Page 51 envs 3020 Page 52 envs 3020 Page 53 envs 3020 Page 54 envs 3020 Page 55 envs 3020 Page 56 4 - Pesticide Formulations January 31, 2025 9:24 AM FOR CHEMISTRY CONTENT: POLAR AND NON-POLAR MOLECULE. IS IT GOING TO DISSOLVE OILS AND FATS. DON'T NEED TO MEMORIZE WHAT THE PESTICIDE SPECIFICALLY IS. BENZENE RINGS, CHLORINE, NON-POLAR. OH GROUPS, OXYGNE, POLAR. envs 3020 Page 57 envs 3020 Page 58 envs 3020 Page 59 envs 3020 Page 60 envs 3020 Page 61 envs 3020 Page 62 envs 3020 Page 63 envs 3020 Page 64 envs 3020 Page 65 envs 3020 Page 66 envs 3020 Page 67 envs 3020 Page 68 envs 3020 Page 69 envs 3020 Page 70 envs 3020 Page 71 envs 3020 Page 72 envs 3020 Page 73  Surfactants: allow things to be absorbed by the plant or insect more effectively. Pesticide will just bead on top of the waxy cuticle of the plant or exoskeleton of the insect without it. Organic pesticides can have surfactant. Surfactants are kind of like an emulsifier. Work like soap works. Only for contact insecticides. Adjuvants improve biological activity of pesticide Spray activators can decrease the degradation of the pesticide Utility modifiers can maintain the integrity of the solution. Stops precipitate from forming and solution stays well mixed. It means that any water used won't affect the efficacy of the pesticide (hard water, high iron water, etc.) Spreaders help coverage. Winter conditioning agents can sequester ions. Binds up Ca and Mg ions so it wont effect pesticides Oil concentrates help get past waterproof barrier. Stickers helps if theres a rain even, the pesticide won't be washed off. envs 3020 Page 74  In Columbia they were using glyphosate to control coca plants. Planes and helicopters fly over coca plants in remote areas to kill the plant. Surfactant called POEA. Its fat that has had polar groups to it (suponified). Like a soapy substance Alkyl polyglucoside is sugar based. Surfactants will always have a polar and non-polar end. They wanted to switch over to the sugar based surfactant because of risk to aquatic ecosystems and off target spread. envs 3020 Page 75  Compatibility agents: sometimes multiple pesticides are mixed in a tank. Sometimes they don't mix well. Added so that multiple active ingredients can be applied at once. Spray thickeners can make is spray less. Every pesticide has adjuvants to improve efficacy. envs 3020 Page 76  Pulse jet uses heat. envs 3020 Page 77  Legal document Negligence will lead someone liable for damages. envs 3020 Page 78 envs 3020 Page 79 6 - Pesticide Use - Forestry January 31, 2025 9:25 AM envs 3020 Page 80 envs 3020 Page 81 envs 3020 Page 82 envs 3020 Page 83 envs 3020 Page 84 envs 3020 Page 85 envs 3020 Page 86 envs 3020 Page 87 envs 3020 Page 88 envs 3020 Page 89 envs 3020 Page 90  Amount of flow occurring in stream envs 3020 Page 91  Concentration of glyphosate Peak is concentration running into stream during rain event First storm event first application theres more runoff into stream. At the low there's almost no detection of glyphosate because it is binding wit the sediment in the stream. The flow might slow and move into a bigger body of water, diluting the glyphosate. envs 3020 Page 92  Subsequent storm events By beginning of september can't detect it. For a month and a half during a storm event, stream is effected. Called exposure characterization envs 3020 Page 93  Time weighted average of different storm events and added them up *remember 6702 Aquatic plants most sensitive, vertebrates, fish, etc. less susceptible. envs 3020 Page 94 envs 3020 Page 95  Size of circle represents number of samples Target flow events and storm events aplication envs 3020 Page 96 envs 3020 Page 97 envs 3020 Page 98 envs 3020 Page 99 envs 3020 Page 100 envs 3020 Page 101 envs 3020 Page 102  Further to right, less sensitive Further to left, more sensitive (above 50%) Surfactant is different for the formulations. Surfactant is responsible for toxicity to fish and invertebrates, not the glyphosate. envs 3020 Page 103  Probable carcinogen (2A) envs 3020 Page 104  IARC doesn't account for probability or level of exposure. Regulator looks at the level that would actually increase risk. Humans can metabolize glyphosate really well. Chemicals we have to worry about is ones that bind to fats and can't be metabolized as easily. envs 3020 Page 105 envs 3020 Page 106 envs 3020 Page 107 envs 3020 Page 108 envs 3020 Page 109