Chapter 18. Environmental Hazards and Human Health. Risk is a measure of the likelihood that you will suffer harm from a hazard. We can suffer from : Biological hazards : from more than 1,400 pathogens. Chemical hazards : in air, water, soil, and food.
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Environmental Hazards and Human Health
Risk is a measure of the likelihood that you will suffer harm from a hazard.
nontransmissible disease- Diseases not caused by living organisms cannot spread from one person to another
WHO estimates that each year the world’s seven deadliest infections kill 13.6 million people – most of them the poor in developing countries.Transmissible Disease
AIDS has reduced the life expectancy of sub-Saharan Africa from 62 to 47 years – 40 years in the seven countries most severely affected by AIDS.
How does this age structure affect the economics of this country?
Should developed and developing nations mount an urgent global campaign to reduce the spread of HIV and to help countries afflicted by the disease?
in TB are due to:
Flu, HIV, and hepatitis B viruses infect and kill many more people each year then highly publicized West Nile and SARS viruses.
Malaria kills about 2 million people per year and has probably killed more than all of the wars ever fought.Case Study: Malaria – Death by Mosquito
Spraying insides of homes with low concentrations of the pesticide DDT greatly reduces the number of malaria cases.
Rabidly producing infectious bacteria are becoming genetically resistant to widely used antibiotics due to:
Increase research on tropical diseases and vaccines
Improve drinking water quality
Reduce unnecessary use of antibiotics
Educate people to take all of an antibiotic prescription
Reduce antibiotic use to promote livestock growth
Careful hand washing by all medical personnel
Immunize children against major viral diseases
Oral rehydration for diarrhea victims
Global campaign to reduce HIV/AIDS
Fig. 18-8, p. 424
Long-term exposure to some chemicals at low doses may disrupt the body’s:
Molecules of certain synthetic chemicals have shapes similar to those of natural hormones and can adversely affect the endocrine system.Effects of Chemicals on the Immune, Nervous, and Endocrine Systems
The world’s worst industrial accident occurred in 1984 at a pesticide plant.
Factors determining the harm caused by exposure to a chemical include:
Typical variations in sensitivity to a toxic chemical within a population, mostly because of genetic variation.Who toxins affect…
Children breathe more air, drink more water, and eat more food per unit of body weight than adults.
Under existing laws, most chemicals are considered innocent until proven guilty, and estimating their toxicity is difficult, uncertain, and expensive.
Some scientists and health officials say that preliminary but not conclusive evidence that a chemical causes significant harm should spur preventive action (precautionary principle).Prevention vs. Reaction
Scientists have developed ways to evaluate and compare risks, decide how much risk is acceptable, and find affordable ways to reduce it.RISK ANALYSIS
Number of deaths per year in the world from various causes. Parentheses show deaths in terms of the number of fully loaded 400-passenger jumbo jets crashing every day of the year with no survivors.RISK ANALYSIS
We can carefully evaluate or tune out of the barrage of bad news covered in the media, compare risks, and concentrate on reducing personal risks over which we have some control.Becoming Better at Risk Analysis