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
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*
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
They had to pump oxygen and carbon dioxide to keep things
Cell phone radiation distorts bees natural tendency to come back to
The nectar available to them wasn’t available in as much variety as
usually available to them in a natural environment.
[we talked about the traditional methods in the earlier lecture]
Roundup used on weed, dandelions. It is banned for cosmetic
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]
Was having an impact on biodiversity in aquatic systems, especially
the amphibian populations.
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
Atrazine – toxicity
In some cases, the affects could be reversible but in this case, it is
chronic cannot be reversed.
Used on a wide variety of plants.
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.
Cucurbit Methyl Bromide was used to save crops like this.
Anything that enters into ground water and leaches it is not good
for the environment. Its suspected to be a carcinogen.
[you don’t need to know these in regards to what it is used for]
Know what is its role in Canada.
“Just buy what I’m saying”.
What is Fertilizer?
Too much is toxic.
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
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
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
Effects of Excess Fertilizers
Artificial application of the fertilizers is causing atmospheric
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
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
Affects commercial fisheries and biodiversity.
Areas where dissolved oxygen is low, the (fish) catch is really low
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”
“Methemoglobinemia” causes problems with the red blood cells
and the transport of oxygen.
Ammonia dominates Ammonium.
Causes frog deformities.
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
Obligation to mitigate harm.