KATHY HUANG & KERRY WALSH

Chapter 17: Environmental Hazards and Human Health

17-1: What Major Health Hazards Do We Face?

Risk: probability of suffering harmPossibility vs. ProbabilityRisk assessment: how much harm a

particular hazard can cause to human health or environment

Risk management: whether or how to reduce risk to certain level and at what cost

17-1

Five major types of hazards: Biological hazards (pathogen) Chemical hazards Physical hazards Cultural hazards Lifestyle choices

17-2 What Types of Biological Hazards Do We Face?

Nontransmissible DiseaseInfectious Disease

Transmissible Disease

Epidemic vs. Pandemic Global threat from Tuberculosis

Strikes 9.2 million per year, kills 1.7 million per year

3 Most Widespread and Dangerous Viruses

Influenza, or flu virus Transmitted by the body fluids or airborne emissions of infected person

HIV (human immuno-deficiency virus) Infects about 2.5 million people each year Results in AIDS

Hepatitis B virus (HBV) Damages liver & kills about a million peopleper year

Growing Global Threat from Tuberculosis

Kills 1.7 million people per year 84% of them in developing countries

Too few TB screening programs, most strains have developed genetic resistance 1) Reproductive rate of bacteria 2) spread of bacteria

around the globe- allow for increased genetic resistance

Multi-drug resistant TB

Malaria- Case Study

About one of every five people in the world at risk from malaria

Bites of certain mosquito speciesKills 1-2 million each yearPeople with HIV more vulnerable to malariaNew antimalarial drugs

Artemisinins Too little funding

Helping to Prevent Infectious Diseases

Reduce poverty

Decrease malnutrition

Improve drinking water quality

Reduce unnecessary use of antibiotics

Educate people to take all of an antibiotic

Careful hand washing

Immunize children

Oral rehydration therapy

17-3: What Types of Chemical Hazards Do We Face?

Toxic chemical: can cause temporary or permanent harm or death to humans & animals

3 major types of potentially toxic agents: Carcinogens: arsenic, benzene, chloroform Mutagens: chemicals & forms of radiation Teratogens: angel dust, benzene, cadmium

Potential pathways on which toxic chemicals move through the living and

nonliving environment

17-3

• Immune system• Neurotoxins can harm nervous system– Ex. PCBs, methyl mercury, arsenic

• Endocrine system• Hormonally active agents (HAAs)• Estrogen mimics• Hormone blockers• Gender benders• Thyroid disrupters

• Phthalates

17-4 How Can We Evaluate and Deal with Chemical Hazards?

Factors determining effects of a chemical: Toxicology: study of poisons Toxicity: measure of how harmful a substance is Dose: amount of harmful chemical ingested, inhaled,

etc. Response: damage to health

Acute vs. Chronic

Case reports0Epidemiological Studies

17-4

Laboratory animals and nonanimal tests to estimate toxicity 2-5 years Dose-response curve

Nonthreshold dose-response model Threshold dose-response model

17-4 Are Trace Levels of Toxic Chemicals Harmful?

17- 4: Precautionary Principle

Pollution preventionTwo major changes:

New chemicals would be assumed harmful until studies prove otherwise

Existing chemicals that have change of causing harm removed from market until safety is established

European Union 2000ban of 12 most notorious persistent organic

pollutants 2006required registration of 30,000 untested

chemicals

17-5: How Do We Perceive Risks and How Can We Avoid the Worst of Them?

Risk analysis Risk assessment Comparative risk analysis Risk management Risk communication

Greatest risk: Poverty malnutrition, increased susceptibility to normally

nonfatal infectious diseases, unsafe drinking water

Ways to reduce risk of premature death: Avoid smoking, exercise regularly, avoid excess

sunlight

17-5

• Reliability• System reliability (%) = Technological

reliability x Human reliability• Evaluating risks (fear, degree of control,

catastrophic or chronic, optimism bias, instant gratification, unfair distribution of risks)

• Guidelines for evaluating and reducing risk– Compare risks, determine how much risk willing to

accept, determine actual risk involved, concentrate on evaluating and carefully making important lifestyle choices

Smoking

EU (European Union) Commission trying to ban smoking in public places in 2011

Health experts urging for $3-5 federal tax for each pack of cigarettes in the U.S. to make up for health, economic, and social costs associated with smoking

Media coverage of harmful health effects of smoking attributed to decline in smoking http://www.youtube.com/

watch?v=SfAxUpeVhCg&feature=related

Cholera Outbreak in Haiti

October, 2010 Spread through ingestion of contaminated food or drinking

water Large scale exposure to contaminated food or water Unclear how cholera was introduced to Haiti

Not related to earthquake in January 2010 Acute, diarrheal illness Infection of intestine by vibrio cholerae In November, 1,344 dead

Carcinogens Found in Baby Toiletries

March 2009 Products like Johnson &

Johnson Baby Shampoo and Baby Magic lotion tested positive for 1,4-dioxane or formaldehyde

Byproducts of the manufacturing process

Campaign for Safe Cosmetics claims that the contamination is unnecessary, while Johnson & Johnson claims that the FDA considers the trace levels of contaminates safe

Works Cited

http://www.nacsonline.com/NACS/News/Daily/Pages/ND1013104.aspx

http://articles.cnn.com/2010-11-22/world/haiti.cholera.alert_1_cholera-outbreak-cholera-epidemic-rehydration-salts?_s=PM:WORLD

http://www.saidaonline.com/en/newsgfx/Cholera%20Haiti-saidaonline.jpg

http://www.washingtonpost.com/wp-dyn/content/article/2009/03/12/AR2009031202940.html