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Lecture notes.docx

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Environmental Science
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EESB16 - Lecture 3 1/24/2012 11:17:00 AM Study with the lec slides: 1) Crop protection chemicals are banned because they might enter the water table. It could have an affect on un-harmful organisms. 2) Chemists know in details as to what each of the these chemicals can potentially do. For midterm, it is good to know the nature of some of the important chemicals. 3) Bats eat a lot of mosquitos. Fungicides could have adverse affects on bats – we do not know. 4) Lecture 4 1/24/2012 11:17:00 AM *Salmon population in BC affected by a virus* Cindy’s homework  Biosphere 2: great big dome in Arizona, people were expected to live in an artificial environment for 2 years and it didn’t work out well.  They had to pump oxygen and carbon dioxide to keep things running smoothly. CCD  Cell phone radiation distorts bees natural tendency to come back to their hives.  The nectar available to them wasn’t available in as much variety as usually available to them in a natural environment. Industrialization  [we talked about the traditional methods in the earlier lecture] Glyphosate  Roundup  used on weed, dandelions. It is banned for cosmetic purposes.  Polyehtoxylatedtallowamine  enhances the activity of the glyphosate. It makes the accessibility of the glyphosate increase.  Broad spectrum  target wide range of plants, only some of them target particular plants. Glyphosate – structure, properties  integrates slow that is why it is environmentally problematic.  absorbs to soil  you don’t want to do that. [you will just be asked about the general properties, name, formula, nitrogen cycle, degradation pathway, etc won’t be asked] Polyehthoxytallowamines  Was having an impact on biodiversity in aquatic systems, especially the amphibian populations. Atrazine  photosynthetic process disrupted somehow (ETC affected)  worse than glyphosate, disintegrates slowly and persists longer, affects a large number of non target species. Atrazine – problems  There is research being done as to whether the previous application had any ongoing damage to the environment (last point on the slides) Atrazine – toxicity  In some cases, the affects could be reversible but in this case, it is chronic  cannot be reversed. Acetochlor  Used on a wide variety of plants. Methyl Bromide  Used to sterilize the microbial population in the soil. Its harmful because it might kill the nitrogen fixing bacteria, myccorhizaea (fungi) might also be killed. Critical use criteria  Is when your exempt from using the chemical. If you’re in a developing country and if there is no other feasible alternative, then you can produce a case and might use it. But you have to show that you tried everything else and it didn’t work. Exemptions granted  Cucurbit  Methyl Bromide was used to save crops like this. Dichloropropene  Kills nematodes.  Anything that enters into ground water and leaches it is not good for the environment. Its suspected to be a carcinogen. Metam Sodium  Targeting fungicides.  [you don’t need to know these in regards to what it is used for]  Know what is its role in Canada. Fertilizers  “Just buy what I’m saying”. What is Fertilizer?  Too much is toxic. Inorganic Fertilizer  Nitrogen fertilizers.  Haber Bosch  high temperature, pressure process.  [just know the deleterious affects on the environment. Chemistry specifics won’t be asked on the exam]  There was a limited supply of these macronutrients to the environment. We tend to think that P is not limited, but it is a limiting nutrient. Recycling of these nutrients was also important.  [just read the slides with lots of text on them]  There is a dichotomy --> debate between living space and growing space.  Mining of phosphorus has also increased.  There has been a problem with recycling these nutrients  see the slide that starts with “where animals….” Fate of Ammonium and Nitrate  The form determines how toxic the chemical is. Canadian Nutrient Sources  Agriculture is responsible for the largest chunk of nutrient and phosphorus extraction. Fertilizer efficiency  Loss of nitrogen is controlled via “slow release fertilizers”. Fate of phosphates  Causes algal growth.  It is "immobile” because it is only partially soluble in soil and the rest of it precipitates with other chemicals. It doesn’t evaporate easily. Effects of Excess Fertilizers  Artificial application of the fertilizers is causing atmospheric problems. Eutrophication – coastal.  Coastal areas are more affected than small water lakes.  Vast tomb  millions of organisms die because of the lack of oxygen  it creates a dead zone. Non point sources  not from ubiquitous sources, largest contributor. Graph: MARB means Mississippi River Basin  showing input of different fertilizers. How the Dead Zone forms  Transition from a healthy form to a dead zone.  Dead zone is expanding  coastal or fresh water bodies.  Excess fertilizer transforming into vast tomb. Jellyfish increase in dead zones…  They seem to be surviving in the dead zones. They are becoming a related problem. They are reducing resources available to commercial fish [Jelly fish sting too]. They eat all the plankton. Oceanic dead zones  Hypoxic.  Affects commercial fisheries and biodiversity.  Areas where dissolved oxygen is low, the (fish) catch is really low as well.  The documented dead zones increased from 10 in 1960 to 405 in 2008. They affect the food availability. Nitrate levels in drinking water  Surpluses of nitrate. Caused problems in very young children. Nitrates in Europe  There has been bigger problems outside of Canada with nitrates and other chemicals. We don’t observe that in Canada because Canada has a lot of freshwater.  The impact may not manifest itself right away but we should be cautious  “significant time lag” Nitrates/Nitrites  “Methemoglobinemia”  causes problems with the red blood cells and the transport of oxygen. Ammonia toxicity  Ammonia dominates Ammonium.  Causes frog deformities. Toxic Blooms  There are certain forms of bacteria (photosynthetic bacteria) that will multiply if they are given the right environment. Annual Greenhouse Gas Emissions by Sector  Broad representation of some of the bad consequences of increase in greenhouse gases. Do we only adopt agricultural practices that can make money for a larger segment of society?  Commodification of food  Some countries have excess food and others starve. Is it always about the money? Midterm Material  Read the readings  if you read them you should be able to recognize. Lecture 5 – February 7, 2012 1/24/2012 11:17:00 AM Stewardship  Obligation to mitigate harm.
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