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
system
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
organophosphates
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 b
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