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Lecture 4

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University of Waterloo
Environmental Studies
ENVS 195
Christine Dupont

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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