KATHY HUANG & KERRY WALSH Chapter 17: Environmental Hazards and Human Health

17-1: What Major Health Hazards Do We Face? Risk: probability of suffering harm Possibility vs. Probability Risk 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 Disease Infectious 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 people per 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 species Kills 1-2 million each year People with HIV more vulnerable to malaria New 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 reports0 Epidemiological 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 prevention Two 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  2000  ban of 12 most notorious persistent organic pollutants  2006  required 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  h?v=SfAxUpeVhCg&feature=re lated h?v=SfAxUpeVhCg&feature=re lated

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 es/ND aspx es/ND aspx 22/world/haiti.cholera.alert_1_cholera-outbreak- cholera-epidemic-rehydration-salts?_s=PM:WORLD 22/world/haiti.cholera.alert_1_cholera-outbreak- cholera-epidemic-rehydration-salts?_s=PM:WORLD 20Haiti-saidaonline.jpg 20Haiti-saidaonline.jpg dyn/content/article/2009/03/12/AR html dyn/content/article/2009/03/12/AR html