Download - Risk, Toxicology and Human Heath
G. Tyler Miller’sLiving in the Environment14th EditionChapter 19
Risk, Toxicology, and Human HealthRisk, Toxicology, and Human HealthRisk, Toxicology, and Human HealthRisk, Toxicology, and Human Health
Shohail Motahir ChoudhuryShohail Motahir Choudhury
Key ConceptsKey Concepts
Types of hazards people face Methods of toxicology Types and measurement of chemical
hazards Types and effects of biological hazards Risk estimation, management, and
reduction
Types of hazards people face Methods of toxicology Types and measurement of chemical
hazards Types and effects of biological hazards Risk estimation, management, and
reduction
Hazard and RiskHazard and Risk
AA riskrisk is a measure of your likelihood of suffering harm from a hazard.
Risks and hazards—some avoidable, some not—compromise everyday life.
Hazard Hazard may cause injury, disease, economic loss, or may cause injury, disease, economic loss, or environmental damage.environmental damage.
Risk assessmentRisk assessment is projected as a probability: It gives is projected as a probability: It gives the estimate of an event’s actually happening.the estimate of an event’s actually happening.
Risk managementRisk management involves deciding whether or how involves deciding whether or how to reduce a particular risk to a certain level and at to reduce a particular risk to a certain level and at what cost.what cost.
Hazard identificationWhat is the hazard?
Probability of riskHow likely is the event?
Consequences of riskWhat is the likelydamage?
Risk AssessmentRisk Assessment Risk ManagementRisk Management
Comparative risk analysisHow does it comparewith other risks?
Risk reductionHow much shouldit be reduced?
Risk reduction strategyHow will the riskbe reduced?
Financial commitmentHow much moneyshould be spent?
4 major types of hazards.4 major types of hazards.1.1. Cultural hazard:Cultural hazard: unsafe working unsafe working
conditions, smoking, poor diet, drugs, conditions, smoking, poor diet, drugs, unsafe sex, poverty, criminal assault, etc.unsafe sex, poverty, criminal assault, etc.
2. 2. Chemical hazardsChemical hazards are harmful chemicals are harmful chemicals in the air, water, soil, and food.in the air, water, soil, and food.
3. 3. Physical hazardsPhysical hazards : radioactivity, fire, : radioactivity, fire, earthquake, floods, etc.earthquake, floods, etc.
4. 4. Biological hazards:Biological hazards: pathogens, pollen, pathogens, pollen, other allergens, and animals such as bees other allergens, and animals such as bees and poisonous snakes.and poisonous snakes.
Toxicology: Assessing Chemical Toxicology: Assessing Chemical HazardsHazards
Toxicity measures how harmful a substance Toxicity measures how harmful a substance is in causing injury, illness, or death to a is in causing injury, illness, or death to a living organism. living organism.
Harm depends on factors:Harm depends on factors:
Dose:Dose: amount of a substance. amount of a substance. Frequency of exposureFrequency of exposureAge and sizeAge and size of the individual exposed, of the individual exposed,Body’s Body’s detoxification systemdetoxification system, and, andGenetic makeupGenetic makeup of the individual, of the individual,
Five major factorsFive major factors can affect the harm caused by a substance. can affect the harm caused by a substance.
Solubility:Solubility: Water-soluble toxins can move throughout the Water-soluble toxins can move throughout the environment. Oil- or fat-soluble toxins can in the body.environment. Oil- or fat-soluble toxins can in the body.
Persistence:Persistence: resist breakdown and have long-lasting harmful effects. resist breakdown and have long-lasting harmful effects.
Bioaccumulation:Bioaccumulation: absorbed and stored in the body at higher than absorbed and stored in the body at higher than normal levels.normal levels.
Biomagnification:Biomagnification: moved up from one trophic level to the next higher moved up from one trophic level to the next higher one.one.
Chemical interactions:Chemical interactions: can decrease or multiply the harmful effects. can decrease or multiply the harmful effects. Antagonistic interaction reduces. Synergistic interaction Antagonistic interaction reduces. Synergistic interaction multiplies the harmful effects.multiplies the harmful effects.
DDT in fish-eatingbirds (ospreys)
25 ppm
DDT in largeDDT in largefish (needle fish)fish (needle fish)2 ppm2 ppm
DDT in smallDDT in smallfish (minnows)fish (minnows)0.5 ppm0.5 ppm
DDT inDDT inzooplanktonzooplankton0.04 ppm0.04 ppm
DDT in waterDDT in water0.000003 ppm,0.000003 ppm,Or 3 ppmOr 3 ppm
VerySensitive
Majorityof population
VerySensitive
00 2020 4040 6060 8080
Dose (hypothetical units)Dose (hypothetical units)
Nu
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aff
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um
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of
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s a
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Effects can be chronic or acute.
PoisonsPoisons
25
100100
7575
5050
00 22 44 66 88 1010 1212 1414 1616
Per
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Per
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Dose (hypothetical units)Dose (hypothetical units)
LD50
Fig. 16.5, p. 400See Table 16-1 p. 400
Five top toxic named by the EPA:Five top toxic named by the EPA: arsenic, lead, mercury, vinyl arsenic, lead, mercury, vinyl chloride, and polychlorinated chloride, and polychlorinated biphenyls.biphenyls.
A poison or toxin is a chemical that adversely affects A poison or toxin is a chemical that adversely affects the health of a living human or animal by causing the health of a living human or animal by causing injury, illness, or death.injury, illness, or death.
Lethal Dose:Lethal Dose: estimating toxicity
A median lethal dose (LD50)A median lethal dose (LD50) for a for a chemical is the amount in one dose chemical is the amount in one dose that kills 50% of the test animals that kills 50% of the test animals within a 14-day period.within a 14-day period.
Chemical HazardsChemical Hazards
Toxic chemicals can kill, and hazardous chemicals Toxic chemicals can kill, and hazardous chemicals can cause various types of harm.can cause various types of harm.
3 major types of toxic agents: 3 major types of toxic agents: MutagensMutagens are chemicals or ionizing radiation that are chemicals or ionizing radiation that cause or increase random mutations in the DNA cause or increase random mutations in the DNA molecules. No safe threshold for exposure. molecules. No safe threshold for exposure.
Teratogens Teratogens are chemicals that cause harm or are chemicals that cause harm or birth defects to a fetus or embryo. Ex: Alcoholbirth defects to a fetus or embryo. Ex: Alcohol
CarcinogensCarcinogens are chemicals or ionizing radiation are chemicals or ionizing radiation that cause or promote cancer.that cause or promote cancer.
Biological Hazards: DiseasesBiological Hazards: Diseases
Non-transmissible disease:Non-transmissible disease: Caused by living organisms, and do Caused by living organisms, and do not spread from one person to another. Examples: cancer, not spread from one person to another. Examples: cancer, diabetes, asthma, malnutrition, and blood vessel disorders. diabetes, asthma, malnutrition, and blood vessel disorders.
Transmissible disease: Transmissible disease: Caused by living organism and spread. Caused by living organism and spread. Infectious agents/pathogens are spread in air, water, food, and Infectious agents/pathogens are spread in air, water, food, and body fluids and by some insects and vectors.body fluids and by some insects and vectors.
Deaths/year : WHO Deaths/year : WHO 30% by non-transmissible cardiovascular disease, 30% by non-transmissible cardiovascular disease,
26% by transmissible infectious disease, 26% by transmissible infectious disease, and 12% by non-transmissible cancers.and 12% by non-transmissible cancers.
As a country industrializesAs a country industrializes infectious disease-caused deaths infectious disease-caused deaths decreases and chronic diseases of adulthood increase.decreases and chronic diseases of adulthood increase.
NEWS:NEWS: Death from infectious diseases has decreased, but many Death from infectious diseases has decreased, but many bacteria have developed immunity to widely used antibiotics.bacteria have developed immunity to widely used antibiotics.
3. Mosquito injects Plasmodium sporozoites into human host
2. Plasmodium develops in mosquito
1. Female mosquito bites infected human, ingesting blood that contains Plasmodium gametocytes
4. Parasite invades blood cells, causing malaria and making infected person a new reservoir
Anopheles mosquito (vector)in aquatic breeding area
eggs
larva pupaadult
Solutions
Infectious Diseases
Increase research on tropicaldiseases and vaccines
Reduce poverty
Decrease malnutrition
Improve drinking water quality
Reduce unnecessary use of antibiotics
Educate people to take all of anantibiotic prescription
Reduce antibiotic use to promotelivestock growth
Careful hand washing by allmedical personnel
Immunize children against major viral diseases
Oral rehydration for diarrhea victims
Global campain to reduce HIV/AIDS
Risk AnalysisRisk Analysis There are scientific ways to evaluate and compare There are scientific ways to evaluate and compare
risk, to decide how much risk is acceptable, and risk, to decide how much risk is acceptable, and find affordable ways to reduce risk.find affordable ways to reduce risk.
Risk assessmentRisk assessment involves identifying hazards and involves identifying hazards and evaluating their associated risks.evaluating their associated risks.
Poverty:Poverty: the greatest risk. Premature deaths per year the greatest risk. Premature deaths per year and reduced life span.and reduced life span.
Reducing povertyReducing poverty would improve human rights, would improve human rights, provide more people with income to stimulate provide more people with income to stimulate economic development, and reduce environmental economic development, and reduce environmental degradation and the threat of terrorism.degradation and the threat of terrorism.
Avoidance of cultural hazardsAvoidance of cultural hazards also improves longevity also improves longevity of life.of life.
Cause of DeathCause of DeathAnnual DeathsAnnual Deaths
11 million (75)Poverty/malnutrition/disease cycle
Tobacco
Pneumonia and flu
Air pollution
HIV/AIDS
Diarrhea
TB
Auto accidents
Work-related injuryand disease
Malaria
Hepatitis B
Measles
5 million (34)
3.2 million (22)
3 million (21)
3 million (21)
1.9 million (13)
1.7 million (12)
1.2 million (8)
1.1 million (8)
1 million (7)
1 million (7)
800,000 (75)
7-10 yearsPoverty
Born male
Smoking
Overweight (35%)
Unmarried
Overweight (15%)
Spouse smoking
Driving
Air pollution
Alcohol
Drug abuse
AIDS
Drowning
Pesticides
Fire
Natural radiation
Medical X rays
Oral contraceptives
Toxic waste
Flying
Hurricanes, tornadoes
Living lifetime near nuclear plant
6-10 years
5 years
2 years
1 year
7 months
5 months
4 months
4 months
3 months
2 months
1 month
1 month
8 days
5 days
5 days
4 days
1 day
1 day
10 hours
Flu
Air Pollution
6 years
5 months
1 month
7.5 years
Hazard Shortens average life span in the United States by
Risk ManagementRisk Management
Risk management means answering the following Risk management means answering the following questions.questions.
How reliable is the risk analysis for each risk?How reliable is the risk analysis for each risk?Which risks have the highest priority?Which risks have the highest priority?How much risk is acceptable?How much risk is acceptable?How much is a life worth?How much is a life worth?How much will it cost to reduce each risk to an acceptable How much will it cost to reduce each risk to an acceptable
level?level?How should funds be spent to provide the greatest How should funds be spent to provide the greatest
benefit?benefit?How will the risk management plan be monitored, How will the risk management plan be monitored,
enforced, and communicated to the public?enforced, and communicated to the public?
Risk AnalysisRisk Analysis
Risk analysis Risk analysis
Comparative riskanalysis
Comparative riskanalysis
Cost-benefitanalysis
Cost-benefitanalysis
Risk management Risk management
Risk perception Risk perception
Riskprobability
Riskassessment
Riskseverity
Is the riskacceptable?
Acceptable ifbenefitsoutweigh costs
Cost–benefit ExpressedpreferencesAcceptable ifpeople agree toaccept the risks
Naturalstandards
Acceptable ifrisk is notgreater thanthose created bynatural hazard
RevealedpreferencesAcceptable ifrisk is notgreater thanthose currentlytolerated
Fig. 16.14, p. 412
Exam and QuizExam and Quiz
Structure of Review ClassStructure of Review Class