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Lecture 3

SCIE 1P50 Lecture Notes - Lecture 3: Top Priority, Bisphenol A, Rachel Carson


Department
Science
Course Code
SCIE 1P50
Professor
Caroline Starrs
Lecture
3

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SCIENCE 1P50 September 22nd, 2016.
Lecture 3
*if something is in the lecture than that is a focus from the article for that week
WATCH: Trashed – Jeremy Irons
- Digester [sp?] in the prison – recreating animal and human digestion – methane
rich bio gas – produces fertilizer that can replace inorganic fertilizers
- Compost
* affordable
* better yields
* better produce
- San Francisco – 75% of homes and offices participate in Zero Waste initiative
* legally obligated to participate as a visitor of San Fran
* only hire ppl from local community (full benefits, pension, unionized)
- Have to utilize limited resources we have
- Recycling industry can create jobs
- We’re at a tipping point
- Sustainability
- Getting very close to the boundaries b/c of what we throw away (stuff leaking into
waterways, overuse of resources, plastic getting into oceans and freshwater
ecosystems)
- Destructive chemicals to species and humans
- Impact of dioxin on aborted fetuses; dioxin & Vietnam; dioxin is still in the
environment and impacting children (neurological development: brain size,
cognitive delays) << make these sorts of chemicals all the time and we encounter
them all the time (burden going onto first born)
ARTICLE FOR SEMINAR WRITE UP: don’t get caught up in names of chemicals
- remember what they are, where we find them, how they’re generated
- this study looks at how to extract them to see how much is in infant (breast milk)
- two populations of nursing moms
- look for controls, blanks
- article is looking at a method
- focus on volumes and comparisons
Environmental Health Risks
some of them we can see and avoid and others that we just don’t know about;
the latter of which tend to cause problems later in life
chemical toxins, infectious agents (bacteria, viruses – very adaptive to survive;
mutate and what used to kill them no longer kills them), radiation (wrecks havoc
on DNA, skin cancer), pollution, trauma
Toxicology – study of toxicants
study mechanisms of toxicity (ie., HOW are they toxic to us; what happens?);
* toxins able to get in through skin, blood, can be breathed in
* 2.5 sized particle in the air (pollution)
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find more resources at oneclass.com

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* some particles are so small we can’t measure (< 2.5)
study how prevent toxic effects
* some toxins we can remediate, take them out of the body; others…there’s
nothing we can do (ex., polonium)
Acute Toxicity – adverse effect that occurs within a short timeframe after
exposure to an amount of toxicant (slightly easier to identify)
Chronic Toxicity – adverse effect that occurs after a long period of low level
exposure to a toxicant (ex., 20-30 years of smoking resulting in cancer) harder to
identify b/c it takes time to show effects
Noninfectious disease – not transmitted from one person to another; result of
chronic toxicity
Infectious disease – transmissible b/w ppl; contaminated food & water (ex., E-
coli, salmonella)
Toxins
Mutagens – agents that damage or alter genetic material (ie., DNA which
majority of is in nucleus and some in mitochondria); can lead to birth defects or
tumors
Teratogens – mutagen that specifically causes abnormalities during embryonic
growth and development
- EX. alcohol – Fetal Alcohol Syndrome; SMOKING which creates PAH
Carcinogens – mutagens that cause cancer
- typically act by shutting down useful gene sequences called tumor suppressors
- Cancer is the 2nd leading cause of death
- 1 in 3 will have cancer in their lifetime in Ontario
Movement, Distribution and Fate of Toxins
- how does it move around?
-Solubility – one of most important characteristics in determining the movement
of a toxin
- how easily it moves through an ecosystem and what is going to carry it along in
ecosystem
-Chemicals are divided into two major groups:
- Those that dissolve more readily in water (hydrophilic). Water soluble
compounds move rapidly through the environment and have access to cells.
Water from our waterways evaporates and becomes transported through
precipitation.
- Those that dissolve more readily in oil/fats/lipids (lipophilic). Fat soluble
compounds need a carrier to move through the environment, but once inside the
body, they penetrate tissues easily. They are stored in body fat and persist for
many years. Females pass their fat onto fetus.
Bioaccumulation and Biomagnification
Bioaccumulation – selective absorption and storage of toxins via ingestion
> Dilute toxins in the environment can build to dangerous levels inside tissues
find more resources at oneclass.com
find more resources at oneclass.com
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