Environmental Hazards Environmental Hazards & Human Health& Human Health

Chapter 18Chapter 18

RiskRisk

The probability, or likelihood, that a The probability, or likelihood, that a harmful consequence will occur as harmful consequence will occur as the result of exposure to a hazard.the result of exposure to a hazard.

Ordering of Perceived Risk for 30 Ordering of Perceived Risk for 30 Activities and Technologies Activities and Technologies WorksheetWorksheet

Fig. 18-12, p. 433

Comparative Risk Analysis

Most Serious Ecological and Health Problems

High-Risk Health Problems • Indoor air pollution • Outdoor air pollution • Worker chemical exposure • Pollutants in drinking water • Pesticide residues on food • Toxic chemicals in consumer products

High-Risk Ecological Problems • Global climate change • Stratospheric ozone depletion • Wildlife habitat alteration & destruction • Species extinction, loss of biodiversity

Medium-Risk Ecological Problems • Acid deposition • Pesticides • Airborne toxic chemicals • Toxic chemicals, nutrients, and sediment in surface waters

Low-Risk Ecological Problems • Oil spills • Groundwater pollution • Radioactive isotopes • Acid runoff to surface waters • Thermal pollution

Transmissible DiseaseTransmissible Disease

WHO estimates WHO estimates that each year that each year the world’s seven the world’s seven deadliest deadliest infections kill 13.6 infections kill 13.6 million people – million people – most of them the most of them the poor in poor in developing developing countries.countries.

Figure 18-5Figure 18-5

DiseaseDisease

Antibiotics/ResistanceAntibiotics/Resistance Know the difference between Know the difference between

epidemic and pandemicepidemic and pandemic Know emerging viral diseasesKnow emerging viral diseases

Viral DiseasesViral Diseases HIV is the second biggest killer virus HIV is the second biggest killer virus

worldwide. Five major priorities to slow worldwide. Five major priorities to slow the spread of the disease are:the spread of the disease are: Quickly reduce the number of new Quickly reduce the number of new

infections to prevent further spread.infections to prevent further spread. Concentrate on groups in a society that are Concentrate on groups in a society that are

likely to spread the disease.likely to spread the disease. Provide free HIV testing and pressure Provide free HIV testing and pressure

people to get tested.people to get tested. Implement educational programs.Implement educational programs. Provide free or low-cost drugs to slow Provide free or low-cost drugs to slow

disease progress.disease progress.

Case Study: Case Study: Malaria – Death by MosquitoMalaria – Death by Mosquito

Malaria kills Malaria kills about 2 about 2 million people million people per year and per year and has probably has probably killed more killed more than all of the than all of the wars ever wars ever fought.fought.

Figure 18-7Figure 18-7

MalariaMalaria

Anopheles mosquito is resistant to Anopheles mosquito is resistant to most pesticidesmost pesticides

Plasmodium parasites are genetically Plasmodium parasites are genetically resistant to most antimalarial drugsresistant to most antimalarial drugs

Ways to reduce spreadWays to reduce spread

CHEMICAL HAZARDSCHEMICAL HAZARDS

A toxic chemical can cause temporary or A toxic chemical can cause temporary or permanent harm or death.permanent harm or death. MutagensMutagens are chemicals or forms of radiation that are chemicals or forms of radiation that

cause or increase the frequency of mutations in cause or increase the frequency of mutations in DNA.DNA.

TeratogensTeratogens are chemicals that cause harm or are chemicals that cause harm or birth defects to a fetus or embryo.birth defects to a fetus or embryo.

CarcinogensCarcinogens are chemicals or types of radiation are chemicals or types of radiation that can cause or promote cancer.that can cause or promote cancer.

Metastasis is the spread of tumors by malignant Metastasis is the spread of tumors by malignant cells breaking off from tumors and traveling in body cells breaking off from tumors and traveling in body fluids to other parts of the bodyfluids to other parts of the body

CHEMICAL HAZARDSCHEMICAL HAZARDS

A hazardous chemical can harm A hazardous chemical can harm humans or other animals because it:humans or other animals because it: Is flammableIs flammable Is explosiveIs explosive An irritantAn irritant Interferes with oxygen uptakeInterferes with oxygen uptake Induce allergic reactions.Induce allergic reactions.

HAA’sHAA’s

PCB’sPCB’s DDTDDT Atrazine, several herbicidesAtrazine, several herbicides Aluminum, mercuryAluminum, mercury Bisphenol-ABisphenol-A PhthalatesPhthalates

ToxicologyToxicology

The science that examines the effects of The science that examines the effects of harmful chemicals on humans, wildlife, and harmful chemicals on humans, wildlife, and ecosystemsecosystems

Toxicity is a measure of how harmful a Toxicity is a measure of how harmful a substance is in causing injury, illness, or substance is in causing injury, illness, or death to a living organism.death to a living organism.

Dose, dose-response curve, LD50 – median Dose, dose-response curve, LD50 – median lethal dose (the dose that kills roughly 50% lethal dose (the dose that kills roughly 50% of a test population within an 18-day period)of a test population within an 18-day period)

Know the factors that can affect the harm Know the factors that can affect the harm caused by a substancecaused by a substance

TOXICOLOGY: ASSESSING TOXICOLOGY: ASSESSING CHEMICAL HAZARDSCHEMICAL HAZARDS

Under existing laws, most chemicals Under existing laws, most chemicals are considered are considered innocent until innocent until proven guiltyproven guilty, and estimating their , and estimating their toxicity is difficult, uncertain, and toxicity is difficult, uncertain, and expensive.expensive. Federal and state governments do not Federal and state governments do not

regulate about 99.5% of the regulate about 99.5% of the commercially used chemicals in the U.S.commercially used chemicals in the U.S.

TOXICOLOGY: ASSESSING TOXICOLOGY: ASSESSING CHEMICAL HAZARDSCHEMICAL HAZARDS

Some scientists and health officials say Some scientists and health officials say that preliminary but not conclusive that preliminary but not conclusive evidence that a chemical causes evidence that a chemical causes significant harm should spur preventive significant harm should spur preventive action (action (precautionary principleprecautionary principle).).

Manufacturers contend that wide-spread Manufacturers contend that wide-spread application of the precautionary principle application of the precautionary principle would make it too expensive to introduce would make it too expensive to introduce new chemicals and technologies.new chemicals and technologies.

RISK ANALYSISRISK ANALYSIS

Annual deaths in the U.S. from tobacco Annual deaths in the U.S. from tobacco use and other causes in 2003.use and other causes in 2003.

Figure 18-AFigure 18-A

RISK ANALYSISRISK ANALYSIS

Number of deaths per year in the world from various Number of deaths per year in the world from various causes. Parentheses show deaths in terms of the causes. Parentheses show deaths in terms of the number of fully loaded 400-passenger jumbo jets number of fully loaded 400-passenger jumbo jets crashing every day of the year with no survivors.crashing every day of the year with no survivors.

Figure 18-13Figure 18-13

RISK RISK ANALYSISANALYSIS

Comparisons Comparisons of risks of risks people face people face expressed in expressed in terms of terms of shorter shorter average life average life span.span.

Figure 18-14Figure 18-14

4 Ways of Becoming Better at Risk 4 Ways of Becoming Better at Risk AnalysisAnalysis

1 – Recognize that everything is risky – the 1 – Recognize that everything is risky – the question is question is howhow risky. risky.

2 – Recognize that the media often gives 2 – Recognize that the media often gives an exaggerated view of risks an exaggerated view of risks

3 – Compare risks3 – Compare risks 4 – Concentrate on the most serious risks 4 – Concentrate on the most serious risks

to your life and health that you have some to your life and health that you have some control over and stop worrying about control over and stop worrying about smaller risks and those over which you smaller risks and those over which you have no controlhave no control