Ch 16 addresses major environmental issues — air, water, and soil pollution, solid/radioactive waste, ozone depletion, greenhouse effect, deforestation, and efforts towards remediation and sustainable development.
Air pollution: particulates (SPM), SO₂ (acid rain), CO (from vehicles), NOx (smog). Control: scrubbers, electrostatic precipitators, catalytic converters. Water pollution: domestic sewage (BOD), industrial effluents, eutrophication (algal bloom → O₂ depletion). Biomagnification: non-biodegradable toxins (DDT) concentrate up food chain. Thermal pollution: heated water reduces dissolved O₂.
Ozone depletion: CFCs → Cl radicals destroy O₃. Montreal Protocol (1987). UV-B increases: skin cancer, cataracts. Greenhouse effect: CO₂, CH₄, N₂O trap heat → global warming → ice melt, sea level rise. Deforestation → soil erosion, desertification, loss of biodiversity, CO₂ increase. Solutions: afforestation, Chipko movement, joint forest management. Integrated waste management: reduce, reuse, recycle. Bioremediation: using organisms to clean up pollutants.
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Biomagnification is the increase in concentration of a non-biodegradable toxic substance (like DDT, mercury) at each successive trophic level in a food chain. Organisms at the top (eagles, humans) accumulate the highest concentrations. For example, DDT concentration was 0.003 ppb in water but 25 ppm in fish-eating birds — a magnification of ~80,000 times. This is because these substances are not metabolised or excreted, and accumulate in fatty tissues.
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