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Lecture 4

GGR203H1 Lecture Notes - Lecture 4: Persistent Organic Pollutant, Immunodeficiency, Acne Vulgaris

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Lecture 4
Prof briefly discusses microbe and drinking water
Virus are so tiny, they can get around water filtration systems and cause diarrhea.
Only Hepatitis A causes a different reaction from most viruses (e.g. liver inflammation)
Parasites are in the water where sewage and animal waste are connected to drinking water and
can cause diarrhea, vomiting
Radionuclide: these are possible to find in water
Alpha emitters
Beta/photon emitters
Combined Radium 226/228
Radon gas (more common in indoor air than in water)
o If it is detected in the indoor air, it is guaranteed to be in the indoor water.
o Radon comes from soil (e.g. house built on soil with uranium). During the breakdown of
uranium, radon is yielded and enters the house through indoor air through holes)
Damage to DNA and our genetic material, increase risk of getting cancer
Inorganic Contaminants
Arsenic: can be found in the natural environment or in industrial environment. Can be
consumed over a long period and cause skin damage, skin discoloration, affect circulatory
Fluoride: added to drinking water to prevent dental damage. In small concentrations, fluorides
don’t harm the body. In excessive concentration, it may cause bone diseases.
Lead: can be found in drinking water and are usually because of leaded pipes. However, it has
been banned for 30 years.
Chemical Hazards in Human Health
To distinguish between natural and manmade chemicals
o Many chemicals are found in our natural environment (e.g. air, soil, water). However, a
natural chemical doesn’t mean a harmless chemical. It may harm our bodies and health.
Focus on today’s lecture is on the manmade chemicals (chemicals that didn’t exist before the Industrial
Revolution). Human bodies now have hundreds of manmade/synthetic chemicals
More than 70 000 synthetic chemical have been created and 15 000 chemicals are being created
each year.
Endocrine Disrupters:
o Endocrine Glands: produce hormones and regulate many processes and activities.
o Endocrine Disrupters interrupt the production and function of hormones.
o Work directly or indirectly.
o It directly binds to human receptors and as a result, some genes may be affected by
function and appearance. This can change levels of produced hormones.
o Indirectly they can affect the production, transport and metabolism of the hormones.
o We are exposed on a daily basis to these chemicals and most adults will not experience
adverse effects to this
o However, fetuses are very sensitive to this. If a mother with a low levels of thyroid
hormones due to the endocrine disrupters, she will need to take medication because
the fetus will be greatly affected (e.g. psychological maladies).
DES (diethlystilbesteol)
It is a synthetic estrogen used by physicians to prevent spontaneous
abortion (1948-1971) and more than one million women took this and
was administered for the first 35 weeks.
However, child, when older, developed some defects: 1) reproductive
organ dysfunction; abnormal pregnancies; reduction in fertility; immune
system disorders; and cancer.
o Other health implication: feminization of males; abnormal sexual behaviour; birth
defects; altered time to puberty (e.g. very early or very late); cancer of mammary glands
or testis; thyroid dysfunction
o Some neurobehavioral effects: two chemicals are very significant PCBs and
Prenatal and early postnatal exposures
PCBs: poor IQ tests; some disabilities; distractibility
Organelle phosphates are responsible for brain development problems
Chemical Body Burdens:
o The quantitative amount of chemicals in our bodies that accumulates over times
o Most of the data is based on ANIMAL studies and can’t be done on humans because it is
unethical. Therefore, these data are somewhat comparable to humans but they are
great indicators of the direction of study.
o They are not stable over time. Their amount in the body changes over time because the
human body (special organs) may break down or rearrange the chemicals into other
chemicals. As well it is not distributed evenly throughout the body. For example, the
o There are some chemicals detected using detecting methods, but some are in so low
concentrations that they are not traceable.
o In Canada and the USA there is a program called biomonitoring which monitors the
common population to see how many chemicals are present in the average person and
if there are any health risks present.
Dioxins: gas when emitted but when then it becomes a chemical.
o Produced everywhere where there any form of combustion. Hamilton is significantly
contaminated with dioxins.
o No commercial usefulness/application. It is the by-product of combustion only. Even
during forest fires dioxins are produced.
o It is also produced during the manufacturing process.
o Dioxins are not just one chemical but a group of chemicals and have very similar
chemical structure. One of the most toxic and studied is 2, 3, 7, 8-tetrachlorodibenzo-p-
dioxin (TCDD).
o The more chlorine in a chemical, the more toxic it is in most general cases.
o Chlorination is the key process in how these chemicals become more toxic and what
affects their chemical properties in the environment. In addition, they affect the
solubility of chemical (e.g. more chlorine equals higher solubility in fats).
o These chemicals are very persistent and hard to remove: persistent organic pollutants
o Dioxins are emitted in air but don’t remain there. Instead, they accumulate in food (e.g.
meat and milk products) and are consumed. Food is the major of contamination in our
o All humans are exposed to low levels of dioxins and the effects of these levels are not
known however.
o Can cause cancer, heart problems, diabetes, immune deficiency
o One symptom that is evident that cause acne
o Subject of great concern
o It is used as agricultural pesticide
o It controls diseases such as malaria and typhus
o It breaks down to DDE and DDD
o Contributed greatly in the Green Revolution: more growth of agriculture
o Lasted for a couple of decades and was later realized it may affect the human health
o In the 1970s scientist discovered that it DDT harms the human health.
o The DDE and DDD are very dangerous to the human health compared to the parent
chemical DDT
o DDT travels long distances and found everywhere in the world due to global distillation
or “grasshopper effect”: it is the effect with multiple cycles of evaporation and
condensation of wind/air cycles.
o In the North Pole, there is a higher concentration of these chemicals because they
condense and do not rise back into the air at this point
o This chemical is very persistent and biomagnifies like dioxins. Biomagnifications is the
accumulation of a chemical in the food chain.
o The difference between the bioaccumulation and biomagnifications is that
bioaccumulation is the accumulation of chemicals in a certain tissue in a certain
o It accumulates in the fatty tissues, milk (especially breast milk).
o Human effects: carcinogen (linked to breast cancer); damage reproductive system;
damages the liver; can mimic estrogen; and if someone is exposed chronically (long
period) it can affect the nervous system.
o It is banned in many countries but can be used for great epidemics or emergencies.