Risk, Toxicology, and Human Health Brian Kaestner Saint Mary’s Hall Brian Kaestner Saint Mary’s Hall Thanks to Miller and Clements

Key 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

Risk and Probability  Risk  Probability  Risk assessment  Risk management Hazard identification What is the hazard? Probability of risk How likely is the event? Consequences of risk What is the likely damage? Risk AssessmentRisk Management Comparative risk analysis How does it compare with other risks? Risk reduction How much should it be reduced? Risk reduction strategy How will the risk be reduced? Financial commitment How much money should be spent?

Hazards  Cultural hazards  Chemical hazards  Physical hazards  Biological hazards Deaths Cause of Death Tobacco use 431,000 Alcohol use Accidents Pneumonia and Influenza Suicides Homicides Hard drug use AIDS 150,000 95,600 (42,000 auto) 84,400 30,500 19,000 15,000 14,000

Toxicology  Toxicity  Dosage  Bioaccumulation  Biomagnification  Synergism  Response  Acute effect  Chronic effect DDT in water ppm, Or 3 ppm DDT in fish-eating birds (ospreys) 25 ppm DDT in large fish (needle fish) 2 ppm DDT in small fish (minnows) 0.5 ppm DDT in zooplankton 0.04 ppm Very Sensitive Majority of population Very Sensitive Dose (hypothetical units) Number of individuals affected

Poisons  Poison  LD 50  Median lethal dose Percentage of population killed by a given dose Dose (hypothetical units) LD 50

Dose-Response Curves  Dose-response  Nonthreshold  Threshold Nonlinear dose-response Linear dose-response Threshold level Effect Dose Nonlinear dose-response Linear dose-response No threshold Effect Threshold Dose

Chemical Hazards  Hazardous chemicals  Mutagens  Teratogens  Carcinogens  Neurotoxins  Precautionary principle

Biological Hazards: Diseases  Nontransmissible diease  Transmissible disease  Pathogens  Vectors  Antibiotic resistance  Malaria 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 pupa adult

NORTH AMERICA EUROPE SOUTH AMERICA AFRICA ASIA ASTRALIA Areas in which malaria has disappeared, been eradicated, or never existed Areas with limited risk Areas where malaria Transmission occurs

Scientists (Not in rank order in each category) Citizens (In rank order) High-Risk Health Problems Indoor air pollution Outdoor air pollution Worker exposure to industrial or farm chemicals 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 and destruction Species extinction and loss of biodiversity High-Risk Problems Hazardous waste sites Industrial water pollution Occupational exposure to chemicals Oil spills Stratospheric ozone depletion Nuclear power-plant accidents Industrial accidents releasing pollutants Radioactive wastes Air pollution from factories Leaking underground tanks Medium-Risk Ecological Problems Acid deposition Pesticides Airborne toxic chemicals Toxic chemicals, nutrients, and sediment in surface waters Medium-Risk Problems Coastal water contamination Solid waste and litter Pesticide risks to farm workers Water pollution from sewage plants Low-Risk Ecological Problems Oil spills Groundwater pollution Radioactive isotopes Acid runoff to surface waters Thermal pollution Low-Risk Problems Air pollution from vehicles Pesticide residues in foods Global climate change Drinking water contamination

Hazard Shortens average life span in the United States by 7-10 Poverty 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 7.5 years 6 years 5 years 2 years 1 year 7 months 5 months 4 months 3 months 1 month 8 days 5 days 4 days 1 day 10 hours

Risk Analysis  Risk analysis  Comparative risk analysis  Cost-benefit analysis  Risk management  Risk perception Risk probability Risk assessment Risk severity Is the risk acceptable? Acceptable if benefits outweigh costs Cost–benefitExpressed preferences Acceptable if people agree to accept the risks Natural standards Acceptable if risk is not greater than those created by natural hazard Revealed preferences Acceptable if risk is not greater than those currently tolerated

Environmental Cost Benefit Analysis -economic cost -sort term -long term -economic benefits -environmental costs -short term -long term