XII Chap 16 Environmental Issues Flashcards
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
_______________ is a sustainable system for handling human waste
Ecological sanitation, human excreta => fertiliser
What are sanitary landfills?
Substitute for open burning dumps;
waste compacted, dumped in depression and covered with dirt everyday
What are 3 types of waste?
Biodegradable
Non-biodegradable
Recyclable
______________ is critical to disposing hospital waste
Incinerators
50% of the e-waste generated worldwide is dumped in ______________
China, India and Pakistan
___________ is the only solution to treat e-waste
Recycling
Integrated organic farming is a _________ procedure.
cyclical, zero-waste
Two problems with nuclear energy?
- Accidental leakage
2. Safe disposal of radioactive waste
What is the Greenhouse Effect?
Naturally occurring phenomenon - responsible for heating of Earth surface - half incoming radiation is absorbed by Earth’s surface to heat it - re-emits infrared, absorbed by atmospheric gases and radiated back to earth, heating earth again - cycle repeated many times
What are the greenhouse gases?
CO2 and methane
Bad vs good ozone
Bad - lower (troposphere)
Good - upper (stratosphere) - shield absorbing UV rays
Thickness of ozone is measured in __________
Dobson units
Why are UV rays dangerous to living organisms?
DNA and proteins absorb UV rays => breaks chemical bonds within these molecules
What is ozone hole?
Large area of thinned ozone layer over Antarctic region
What has disrupted the balance of ozone degradation and formation?
CFCs - refrigerants - move upwards towards stratosphere - UV acts on them and releases Cl atoms - Cl degrades ozone releasing oxygen
Why are CFCs permanent?
Don’t get used up in the reaction, catalysts
UV radiation of what wavelengths are completely absorbed by earth?
shorter than UV-B
Effects of UV-B?
- Damages DNA => mutation
- Skin - damage, aging and cancer
- Cornea absorbs => inflamed => snow-blindness / cataract in eyes
What is soil erosion and desertification?
fertile top-soil removed due to over cultivation, unrestricted grazing, deforestation, poor irrigation practices
=> dry patches of land
=> desert
What is water logging and soil salinity?
waterlogging - irrigation without proper drainage => draws salts to the surface => thin crust of salt on land, collects at roots of plants and inhibits growth
In India forest cover used to be ____ and it is now ____
30% and it is now 21.54%
___________ is one of the main reasons for deforestation
Agriculture
Slash and burn agriculture?
cut down forest trees, burn plant remains
ash used as fertiliser
after cultivation, area is left to recover for several years => farmers move to next area
when recovery phase is skipped -> deforestation
Slash and burn cultivation is aka?
Jhum cultivation
____________ is the most common source of pollution of water bodies
Domestic sewage
Domestic sewage increases ______ and decreases _______ in receiving water bodies
increases biochemical oxygen demand (BOD)
decreases dissolved oxygen
