Environmental Hazards and Toxicology Quiz

Environmental Hazards

• Hazards categorized as physical (earthquakes, floods), chemical (pesticides, heavy metals), biological (pathogens, allergens), and cultural (smoking, poor diet).

Toxicology and Dose-Response

• Toxicology studies harmful substance effects on organisms.
• Dose-response relationships define how a response changes with varying doses:
  • LD50 (Lethal Dose, 50%) is the dose causing death in 50% of test subjects.
  • ED50 (Effective Dose, 50%) is the dose eliciting a response in 50% of subjects.
  • Threshold level is the lowest dose eliciting a response.
  • Acute exposure is short-term, high-dose; chronic exposure is long-term, low-dose.

Toxic Substances

• Carcinogens cause cancer (e.g., asbestos, benzene).
• Mutagens cause DNA mutations (e.g., radiation, nitrites).
• Teratogens affect embryonic development (e.g., thalidomide, alcohol).
• Neurotoxins harm the nervous system (e.g., lead, mercury).
• Endocrine disruptors interfere with hormones (e.g., BPA, DDT).

Bioaccumulation and Biomagnification

• Bioaccumulation is the gradual build-up of substances within an organism.
• Biomagnification is the increasing concentration of toxic substances along a food chain, such as DDT in birds of prey or mercury in fish.

Risk Assessment and Management

• Risk assessment has these steps:
  • Hazard identification.
  • Dose-response assessment.
  • Exposure assessment.
  • Risk characterization.
• Risk management involves minimizing or regulating exposure.

Epidemiology and Disease

• Epidemiology studies disease spread and risk.
• Emerging infectious diseases are new or rapidly increasing diseases (e.g., COVID-19, Zika).
• Zoonotic diseases are human-animal transmitted diseases (e.g., Ebola, rabies).

Pollution and Human Health

• Air pollution includes particulate matter, ozone, carbon monoxide, sulfur dioxide, nitrogen oxides, and indoor pollutants (radon, tobacco smoke).
• Water pollution involves heavy metals (lead, arsenic), pathogens (cholera, E. coli), and nutrient pollution (eutrophication).
• Soil and food contamination includes pesticides, herbicides, and heavy metals in crops.

Regulatory Agencies and Laws

• Key regulatory agencies include EPA (Environmental Protection Agency), FDA (Food and Drug Administration), and OSHA (Occupational Safety and Health Administration).
• Key laws include the Clean Air Act (1970), Clean Water Act (1972), Toxic Substances Control Act (1976), and Safe Drinking Water Act (1974).

Case Studies

• Examples of significant case studies include Minamata Disease (mercury poisoning), Bhopal Disaster (chemical leak), Flint Water Crisis (lead contamination), and DDT's impact (Rachel Carson's work).