Lecture 10

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McMaster University
Civil Engineering Infrastructure Technology
Jonathan Sussman

Lecture 10 Environmental Hazards to Specific Populations Environmental Hazards to Specific Populations 1. A) Children’s environmental health (a huge topic and the most important)  Why are children so much more harmed than adults?  Because o f the limited diet of children, the behaviour unique to children, how and where children spend their time and the impact of their short height  LIMITED DIET OF CHILDREN o Diseases and illness environmentally related are becoming more popular amongst children o Why are children more at risk? They eat more, drink more and breathe more air in comparison to their body size. o Children eat 3-4 times more food in proportion to their body size than adults o They eat fewer types of food (mostly rely on milk which can contain dioxins from the mother’s breasts) and large quantities of specific foods  An average infant (less than one year old) consumes 15-17 times more apple juice and 14-15 times more pears than adults.  Cow milk products comprise 36% and 58% of the diet of the nursing and non-nursing infants respectively.  Thus a contaminated food can cause great amounts of harm to children.  BEHAVIOUR UNIQUE TO CHILDREN o Mouthing behaviour (2-6 year olds touch their mouths about 9 times every hour)  The mouth is a means of exploring and understanding  This can lead to the ingestion of:  Soils  Paint  Small objects  Infections agents  Disinfection by-products (e.g. from swimming pool) o Children enjoy participation in certain athletics and/or risky activities  Playing in construction sites  Swimming  Risky-playing activities  Exposure to the sun (lack of sun-screen)  Smoking-adolescents  HOW AND WHERE CHILDREN SPEND THEIR TIME o Spend most of their time indoors (where pollution is 2-5 times greater than outside) o The crawl and play on the floor so they are exposed to dust, pollutants, infectious agents, and radon) o Outside they are playing on the grass and are exposed to pesticides and skin infections and maybe even animal feces).  THE IMPACT OF SHORT STATUE o The breathing zone of adults is about 4-6 above the floor or ground o The children’s breathing zone are much lower 2. B) Children’s Environmental Health (Physiological differences between children and adults) o Higher metabolic rate o More active than adults (eat more, drink more and breathe more air)  Dermal absorption o Higher ratio of skin surface area to body weight than adults o Skin is more permeable  Gastrointestinal adsorption o Large surface area of intestines o Prolong gastric emptying time (6-8 hours) o Calcium-lead transport mechanisms  Both these elements have similar transport mechanisms and the body may absorb the lead by accident. Children require a lot of calcium and will absorb a great amount of calcium however, if the body intakes lead by accident, the children will intake too much lead as well o Lower stomach acidity  Respiratory absorption o Children breathe twice as much air as children o Blood-Brain barrier: it is a chemical mechanism that controls the chemicals and substances entering the brain. It is not yet developed in children and thus more chemicals may hurt the brain in a child than in adults.  Other things o Greater blood flow to the brain and other organs o The size of some organs relative to the body mass is greater o Biotransformation process are less developed (metabolism of some chemicals in not available) o Rapid growth and development (plenty of time to bioaccumulate chemicals). o More time to develop chronic disease 3. Women’s health and environment (another popular topic of discussion)  Women have a role in reproduction and in bearing and nursing of children.  The mother’s health influences the health of their children  Women carry more fat (tissues) than men and on average live longer than males and thus can be more affected due to bioaccumulation of chemicals in the tissue  Two illnesses in women are related environmentally: o Breast Cancer: some factors are genes, hormones, and synthetic chemicals o Osteoporosis: it is the fragility of the bones, and is due to the roles of lead and cadmium and could be due to hormones because it appears after menopause 4. Workers and noise hazards  Workers are more exposed to hazards than the general public on a daily basis at least  Workers are exposed to industrial pollutants before the general public  Noise hazards to the ear are the most common occupational hazard. o The damage the sensitive cells lining the inner part of the ear (damage or loss of hearing)  It can result in the loss of hearing high frequency sounds (>4000 Hz). A person may not notice this incapability on daily situations except if detected by the audiologists. They are able to hear speech and environmental noises.  It can also result in the loss of hearing lower frequency sounds (<4000 Hz, within a few years). Person will not be able to hear speech due to surrounding and environmental noises.  More than 85 decibels of the sound is harmful to the ear.  Prevention is the best cure. 5. Elderly and environmental health  There is a rapidly growing population of elderly members in Canada  Chronic diseases and disabilities are due to poor environmental conditions such as: o Lead o Indoor and outdoor air pollution o Microorganisms in water (due to weak immune systems)
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