EESA10H3 Lecture Notes - Lecture 4: Persistent Organic Pollutant, Endocrine Disruptor, Biomonitoring

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20 Apr 2012
Lec 4
Chemical Hazards
Endocrine distrupters.
Glands that produce hormones that regulate many processes in our body.
Some of the chemicals released into the environment are similar in their properties to
hormones. They mimic hormones. Our bodies may uptake them.
They are called endocrine disrupters.
The disrupter binds to the hormone receptor instead of the hormone.
Changes appearance of certain genes, can result in wrong production of proteins. Normal
transport will be interrupted or metabolism of hormone. Those endorcrine disrupters, those
chemicals they are not going to cause very severe effects in adults, but in fetuse. Lower level of
T3 and T4 will not affect women’s health but the health of fetus.
DES took about 20 or more years for science to find out that basically the children of these
women who took DES when they reached to reporoductive stage, the children were affected (ie
reduction in fertility and abnormal pregnancies).
Fetuses much more sensitive to chemicals. Maybe later in their lives at some point they can
have a problem.
Neurobehavioral effects
PCBs may cause impact on learning in nonhuman primates (from animal studies)
Body Burden the amount of chemicals in the body at any given time
Every year, hundreds of new chemicals are released into the environment. These chemicals
should have approval, but sometimes the research is not enough and the chemical is used
before we have a good risk assessment.
No one in the world that doesn’t have any chemicals in the body. The amount of chemicals in
the body depends on where they live.
Our bodies can fight up to a certain point, depending on which chemical. Some chemicals we
can effectively release, some remain in our body.
Every year, our body burden is rising.
Persistent organic pollutants POPs
Take hundreds or thousands of years to breakdown after released in environment.
Sometimes the product of breakdown is even more dangerous.
Dioxins US soldiers used this to spray plants in Vietnam to de-leaf them so they could see the
guerrillas. This resulted in diabetes, different types of cancer in soldiers. They are not produced
in industry or used in products. Dioxins are released in any kind of combustion. Mostly from
incineration of medical waste.
Once dioxin is released into the wild: not toxic in air, it settles on plants, soil, ground. Consumed
by animals, enters food chain and we are exposed. They are not soluble in water, but it fats.
They dissolve in the fat when they enter the food chain.
Dioxins bind to protein, protein is receptor, receptor binds to DNA and affects to normal
function of gene and causes crap in the body.
Bioaccumulation is the buildup of a particular chemical in some tissues in the body over time, in
the same organism
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