XII Chap 16 Environmental Issues Flashcards
(50 cards)
What is pollution?
Undesirable change
physical, chemical or biological
air, water, land or soil
What law did GoI pass to protect environment?
Environment (Protection) Act, 1986
What is an electrostatic precipitator?
Widely used mechanism to separate pollutants in industry
Removes 99% particulate matter - electrode wires => corona => electrons, which attach to dust particles => collecting plates are grounded and attract charged dust particles
What is a scrubber?
Removes gases like SO2 - sulphur dioxide;
Exhaust passed through water or lime spray
_______ is responsible for greatest harm to human health
PM2.5
What are catalytic converters?
Expensive metals as catalysts, fitted into cars
Unburnt hydrocarbons in exhaust => CO2 and water
CO + NO => CO2 and Nitrogen gas
Why should vehicles with catalytic converters use unleaded petrol?
Lead inactivates the catalyst
Air Act 1981 was amended in 1987 to include what?
Noise pollution
What level of noise can damage ear drums?
Brief exposure to 150dB or more (e.g. jet or rocket taking off)
How does noise pollution affect humans?
Sleeplessness
Increased heart beat
Altered breathing
Why is CNG better than diesel?
Burns most efficiently - very little left unburnt
Cheaper
Cannot be siphoned off by thieves
Cannot be adulterated
What is the challenge with switching to CNG?
Pipelines
What are stipulations of Euro III norms?
diesel sulphur - 350 ppm
petrol sulphur - 150 ppm
aromatic hydrocarbons - 42%
eventual goal - 50ppm and 35%
What are current mass emission standards in India?
Bharat Stage IV
How much impurity makes domestic sewage unfit?
0.1%
How does disposing sewage in water cause mortality of fish?
lots of biodegradable organic matter => decomposers consume lot of oxygen => less oxygen for other organisms
What causes algal bloom?
Large amounts of nutrients in water => excessive growth of planktonic (free-floating) algae
=> water quality deteriorates => fish mortality (also toxic to humans)
Where do water hyacinth grow abundantly?
Eutrophic (nutrient-rich) water bodies
What is the difference between domestic and industry waste?
Industry waste => more toxic substances (e.g. heavy metals)
What is biological magnification?
Increase in concentration of toxicant at success trophic levels => because toxic substance cannot be metabolised or excreted
e.g. DDT
Water 0.003 => Zooplankton 0.04 => Small fish 0.5 => Large fish 2 => Birds 25
How does DDT affect birds?
Disturbs calcium metabolism => thin eggshells => premature breaking
What is eutrophication?
natural aging of lake by nutrient enrichment, ends in converting to land, spans thousands of years
Young lakes are warm and as they age and eutrophication occurs, the water becomes colder and shallower. T or F?
False, young => cold, eutrophication => shallower + warmer
What is Cultural or Accelerated Eutrophication?
Pollutants (nitrates and phosphates) accelerate lake’s aging process
