NOISE POLLUTION:
- Undesirable high level of sound is called noise pollution.
Harm full effect of noise pollution:
- Psychological and physiological disorder in humans.
- High sound level, 150dB or more may damage ear drums.
- Noise causes sleeplessness
- Increased heart rate.
- Altered breathing pattern.
Prevention of Noise Pollution:
- Use of sound absorbent materials or by muffling noise in industries
- Demarcation of horn free zones around hospitals and schools.
- Permissible sound levels of crackers,
- Timings after which Loudspeakers cannot be played
WATER POLLUTION AND ITS CONTROL:
Domestic sewage and industrial effluents:
- A mere 0.1 percent impurities make domestic sewage unfit for human use
- Sewage contains dissolve salts like nitrates, phosphates, and other nutrients, and toxic metal ions and organic compounds.
- The amount of organic matter in water is estimated by BOD.
- Biochemical oxygen demand: the amount of Oxygen required oxidizing all organic matter present in one liter of water.
- Changes take place on discharge of sewage into the river.
- Micro-organism involved in biodegradation of organic matter in the receiving water body consume a lot of oxygen, hence there is sharp decline in dissolved oxygen downstream from the point of discharge.
- Due to low DO there is mortality of fish and other aquatic animals.
- Presence of large amount of nutrients in water also causes excessive growth of Planktonic (free floating) algae, called algal bloom.
- Algal bloom imparts distinct color to water bodies.
- Deterioration of water quality and fish mortality.
- Some bloom-forming algae are extremely toxic to human and animals.
- The world’s most problematic aquatic weed is water hyacinth (Eichhornia crassipes) called ‘Terror of Bengal’.
- Introduced to India for their lovely flowers.
- Excessive growth causes blocks in waterways.
- They grow abundantly in eutrophic water bodies.
- Causes imbalance in ecosystem and dynamics of water body.
- Sewage associated with diseases:
- Sewage from home and hospital contain pathogenic microbes.
- Discharge of such sewage without proper treatment causes diseases like dysentery, typhoid, jaundice, cholera etc.
- Toxic heavy metals (defined as elements with density > 5g/cm3), released from:-
- Petroleum industry.
- Paper manufacturing.
- Metal extraction and processing.
- Chemical manufacturing industries.
- Biomagnifications: increase in concentration of the toxicant at successive trophic level is called biological magnification or biomagnifications.
- Toxic substance accumulated by an organism cannot be metabolized or excreted.
- The accumulated toxic passed to the next trophic level.
- This phenomenon is well known for mercury and DDT.
- Bio magnification of DDT in Aquatic food chain.
- Eutrophication: The process of nutrient enrichment of water and consequent loss of species diversity is referred to as Eutrophication.
- Natural Eutrophication:
- Streams draining into the lake increase nutrients like nitrogen and phosphorus.
- Increase in nutrient encourages growth of aquatic organisms.
- Over centuries, as silt and organic debris pileup the lake grows shallower and warmer.
- Warm-water organisms dominate over that thrive in a cold environment.
- Marsh plants take root in the shallows and begin to fill in the original lake basin.
- Eventually the lake gives way to large masses of floating plants (bog), finally converting into land.
CBSE Biology (Chapter Wise) Class XII ( By Mr. Hare Krushna Giri )
Email Id : [email protected]
