Module 12: Environmental Hazards and Human Health; Waste Management

1. Toxicology studies the effects of chemicals on living organisms. Key principle: 'the dose makes the poison' — almost any substance is harmful at a sufficient dose.
2. A dose-response curve plots effect (health outcome) against dose (concentration). The LD50 is the dose lethal to 50% of a test population — used to compare relative toxicity.
3. Carcinogens cause cancer (benzene, asbestos, tobacco). Mutagens alter DNA and can cause heritable changes. Teratogens cause birth defects when a fetus is exposed (thalidomide, alcohol).
4. Routes of exposure: inhalation (lungs), ingestion (swallowing), dermal contact (skin). The route affects how quickly and how severely a toxin affects the body.
5. Environmental justice is the principle that all people, regardless of race, income, or nationality, have the right to a safe, clean environment. Low-income communities and communities of color are disproportionately exposed to environmental hazards.
6. Solid waste hierarchy (in order of preference): Reduce (use less) → Reuse → Recycle → Recover (energy from waste) → Dispose (landfill or incinerate). Reduction is always the best option.
7. Modern sanitary landfills use clay or plastic liners and leachate collection to prevent groundwater contamination. Landfill gas (mostly CH₄) can be captured for energy. Space is limited in densely populated areas.
8. Hazardous waste (flammable, corrosive, reactive, or toxic) is regulated under RCRA in the U.S. Superfund (CERCLA, 1980) funds cleanup of abandoned hazardous waste sites; there are more than 1,300 on the National Priorities List.

Discussion post

1. Takeaways post: What is the one concept from this entire course (M1–M12) that most changed how you see your everyday choices? Explain using the vocabulary from the relevant module.
2. Connect that concept to one specific decision you plan to make differently as a voter or consumer (Course Outcome 5).
3. Reply to two classmates: does their takeaway connect to yours? What would it take to turn both insights into community action?

Netiquette from the syllabus: address ideas, not people. Complete sentences, correct spelling. Personal matters go to email, never the board.

Ask at home: If there were a hazardous waste site being proposed near your neighborhood, what would you want to know — and who would you trust to give you accurate information?

En español: Si se estuviera proponiendo un sitio de desechos peligrosos cerca de tu vecindario, ¿qué querrías saber — y en quién confiarías para darte información precisa?