Chapter 15 – Environmental Hazards and Human Health

27/10/2010 01:06



1. Differentiate between a hazard and a risk. Where does vulenrability fit in?

In terms of environmental health a hazard is anything that can cause (1) injury, disease, or death to humans; (2) damage to personal or public property; (3) deterioration or destruction of environmental components. Hazard has a risk. Risk is the probability of suffering injury, disease, death or some other loss as a result of exposure to a hazard.

The existence of a hazard alone does not mean that undesirable consequences will follow. Risk=Hazard×Vulnerability; Vulnerability to risks: some people are more vulnerable to certain risks than others.


2. Define morbidity, mortality and epidemiology.

Morbidity is the incidence of disease in a population and is commonly used to trace the presence of a particular type of illness (influenza, diarrheal disease etc.). Mortality is the incidence of death in a population. Epidemiology is the study of the presence, distribution and prevention of disease in populations.


3. Describe public-health roles of the CDC and the WHO.

CDC is the Centers of Disease Control and Prevention leading federal agency of public health and safety in U.S. The CDC’s mission is “to promote health and quality of life by preventing and controlling disease, injury, and disability”; public health as prevented and controlled disease, injury, and disability. WHO United Nations agency with the mission of enabling “all peoples to attain the highest possible level of health”; public health as the highest possible level of health.


4. What are the four categories of human environmental hazards? Give examples of each.

Cultural: mortality and disability as a matter of choice or at least could be influenced by choice. People engage in risky behavior and subject themselves to hazards. Sunbathing, consuming alcoholic beverages. Biological: the battle with pathogenic bacteria and viruses. The black plague, malaria. Physical: natural disasters, including hurricanes, tornadoes, floods, forest fires, earthquakes, land slides, and volcanic eruptions. 2004 Indian Ocean tsunami, 2005 August hurricane Katrina in U.S. Chemical: exposure to chemicals such as cleaning agents, pesticides, fuels, paints, medicines, etc. Toxicity depends on dose. Heavy metals as carcinogens.


5. List as many you can of the top 10 risk factors that are responsible for global mortality and disease.

Underweight, unsafe sex, blood pressure, tobacco, alcohol, unsafe water/sanitation/hygiene, cholesterol, indoor smoke from solid fuels, iron deficiency, overweight.


6. Document the efforts to control tobacco use both in the U.S. and globally.

U.S.: tobacco products are highly taxed, warning labels on smoking materials, cigarette advertising is banned on television, promoting smoke-free workplaces, requiring nonsmokers’ areas in restaurants, banning smoking on all domestic airline flights. Global: publication of Framework Convention on Tobacco Control by WHO. This framework requires: raising taxes, restricting advertising, large health warnings on tobacco material, reduce ETS (environmental tobacco smoke=secondhand smoke). Some countries have banned smoking in indoor public places.


7. What is the significance of malaria worldwide, and what are some recent developments in the battle against this disease?

Of the infectious diseases present in the tropics, malaria is by far the most serious, accounting for an estimated 350-500 million cases each year and more than million deaths. Eradication of the anopheles mosquito by using insecticides; Chloroquine drug, artemisinin drug; providing insecticide-treated nets over beds in threat areas; sequence of genomes of Anopheles mosquito and P. flaciparum (most lethal malaria parasite) to target potential weak points in both organisms in the search for new vaccines and drugs.


8. Outline the four steps of risk assessment used by EPA.

Hazard assessment: the process of examining evidence linking a potential hazard to its harmful effects. Dose-response assessment: analyzing the relationship between the concentrations of chemicals in the dose and both the incidence and the severity of the response. Exposure assessment: identifying human groups already exposed to the chemical, learning how their exposure came about, and calculating the doses and length of time of their exposure. Risk characterization: pulling together all the information gathered in the first three steps in order to determine the risk and its accompanying uncertainties.


9. What methods are used to test chemicals for their potential to cause cancer?

Examination of all the people exposed to the chemical; animal testing; human subjects to test the product/chemical; the chemical or process itself (determination of physical/chemical properties and what mode of action might the chemical or process take in incl. cancer).


10. Describe the process of risk assessment for public health as it was recently carried out by WHO. What is DAILY?

For assessment following risk factors were chosen for special attention: potential global impact (the risk is likely to be among the leading causes of poor health and of mortality); high likelihood of causality (it should be possible to trace cause-effect relationships between poor health and the factor in question); modifiability (it should be possible to develop countrywide risk reduction policies); availability of data (there must be reliable data on the prevalence of the risk factor and its relationship to disease and mortality); the data collected must be assessed with the use of a “common currency”, one that facilitates a comparison of different types of risks. DAILY: the “disability-adjusted life year”, one DAILY represents the loss of one healthy year of a persons life; a measurement used by WHO for risk assessment.


11. Discuss the relationship between public risk perception and assessment, on the one hand, and public policy on the other.

Public risk perceptions – peoples intuitive judgments about risk, these are not consistent with the results of coming from a scientific analysis of risk (e.g. risk assessment). The public perception of risks is often more a matter of outrage than hazard. Hazard expresses primarily a concern for fatalities only, outrage expresses a list of additional concerns (lack of familiarity with a technology, risk is voluntary, public impression of hazards, overselling safety, mortality, control, fairness). Moreover public perception of risk is strongly influenced by the media. Public concern drives public policy, as a result some serious risks may get less attention than they deserve.


12. What is the precautionary principle, and how would employing the principle better our approach to environmental public policy?

As the use of risk assessment has come under attack in recent years the precautionary principle was established. The concerns about risk assessment are: (1)it does not adequately reflect the uncertainty inherent in much of the assessment process; (2) it has been largely employed in situations where a chemical or a process is already in use; and (3) the burden of proof of harm falls largely on the regulators. Therefore precautionary measures should be taken where an activity raises threats of harm to human health or the environment, even if some cause-and-effect relationships are not fully established scientifically. In other words the proponent of an activity, rather than the public,should bear the burden of proof.