Soil Pollution 1

Soil Arranged in series of zones is called ‘Soil Horizons’.

Causes of Soil degradation: Soil Erosion: The movement of surface litter and topsoil from one place to another. Due to farming,construction,overgrazing by livestock, burning of grass cover and deforestation. Conservation of soil and water by  Area treatment  Drainage line treatment.

 Continuous contour trenches:

Shallow trenches dug across slope and along contour lines.  Bunds Excess use of fertilizers:N,P,K Nutrients Pesticides-DDT Bio accumulation, Bio-magnification.

Sustainable Agriculture  Crop rotation  Organic farming  Integrated pest management(IPM)

IPM promotes use of biopesticides. Microbial pesticidesbacteria,fungus,virus,protozoa. Biochemical pesticide-effects reproductive and digestive system of the pests.

Biopesticides Examples: Bacillus thuringiensis(Bt) Neem(Azadirachta indica) trichogramma Excess Salts And Water logging: • Irrigation water contains dissolved salts like Nacl which remains in topsoil causing salinization. • Due to water logging, salts gets leached deeper into soil. Roots get enveloped with saline water-plant

 Municipal wastes, sewage  Pesticides, fertilizers  Ship accidents  Offshore oil exploration

Causes:

Control: • Sewage treatment plants  Screening: Its consists of parallel bars spaced 2-7cms apart followed by a wire mesh with smaller openings. Stones,sticks,rags can be removed

 Communiter: breaks the coarse

materials(grinds).  Grit Chamber: light organic settles down.  Primary settling tank: suspended solids settle by gravity.  Chlorinated to destroy bacteria. Primary treatment removes 35% of the BOD and 60% of the suspended solids. Secondary Treatment: viii.Trickling filters ix.Activated sludge process x. Oxidation ponds

iii. Trickling Filter: • • •

It consists of a rotating distribution arm that sprays liquid waste water-fist size rocks. slime(bacteria,fungi,algae) which degrades waste. slime slides and get collects at the bottom of the filter.

iii. Oxidation ponds: - large shallow ponds approximately 1-2m deep where sewage is decomposed by microorganisms. - accommodate large fluctuations in flow and low cost. Pollution due to oil:  Tanker operations(ballast)  Dry clocking  Tanker accidents  Offshore oil production

Effects of Marine Pollution:  Red tides-phytoplankton blooms of such intensity that whole area is discolored.  Oil slick-removes air present between birds skin and feather, bird sinks.  Tainting-unpleasant flavor of fish and seafood due to oil silks.