Transcript Soil pollution

Soil pollution
SOIL POLLUTANTS
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Plastics
Agro chemicals
Fertilizers
Heavy metals
Plastics
• Major part of global domestic and industrial waste
• Not easily biodegraded
• Waste plastic accumulates much thus adds to severe pollution
problem
• Takes several years to disintegrate – 400 years to degrade mineral
water bottles
• In USA, plastics are 7% in weight and 30% of the volume
• Use of biodegradable plastic solves the problem of pollution
Agrochemical pollution
• Include pesticides, herbicides, fungicides
• Pesticides applied reach the soil ultimately
• Accumulation of pesticide residues in biosphere
creates ecological stress causing soil, water and
food contamination
• Persisting chemicals are hazardous to human
health
• Total remediation is impossible
• Reduction of residue levels through redeeming
technology (desirable)
Fertilizer pollution
• Continuous application – Deterioration in soil
properties, cultivated soils lose their characteristics
• Application of Amm. sulphate, Amm. chloride & Urea
reduce soil pH
• Crops – potato, grapes, citrus, beans – sensitive to
chloride toxicity
• Application of organic manures and biofertilizers reduce
the soil from pollution
Heavy metal pollution
Metals with atomic number greater than 23 or more
than 5 gm per ml (eg. Hg – 70gm
ml-1)
• They are hazardous, not acceptable to biological
system
• Toxic to man & other life forms
• Most are slow poison, accumulate in the body and
cause serious disorders
• Common toxic metals- Hg, Pb, As, Cr, Cd
Heavy metal (forms)
Source
Effect
Mercury – Hg++
Methyl
mercury Irreversible neurological
fungicides, electrical and damage
in
man,
electronic
industries, Minamata disease
PVC, plastics, paints
Lead - Pb2+ , Pb4+
Automobile exhaust of Mutation in algae and
leaded petrol, batteries, bacteria, blackening in
pipes, soldering
fish, gradual paralysis in
man
Arsenic – As++,
Arsenic trioxide,
Sodium arsenate
Herbicide,
fungicide,
wood preservative –
Agrochemicals
(70%),
paints, bullets (20%),
glass wares (5%)
Accumulate in hair, nail,
skin lesions, act as
oxidative
uncoupler,
damage
to
kidney,
respiratory and nervous
disorders
Contd.
Chromium – Cr+6
& CrO3
Tanneries, electroplating
and
metal
finishing
processes, Khaki dyeing
textiles
Toxic
to
aquatic
organisms, absorbed
through intestinal tract
in man
Cadmium - Cd
Pigment and stabilizer for
PVC, plastics, tyres,
rechargeable
cells,
electroplating, coal oil,
phosphate rocks
Bones become brittle –
Itai Itai disease in
Japan, gastro enteric
distress and pain
Control of soil pollution
• Use of pesticides and fertilizers should be minimized.
• Cropping techniques should be improved to prevent
growth of weeds.
• Special pits should be selected for dumping wastes.
• Controlled grazing and forest management.
• Wind breaks and wind shield in areas exposed to wind
erosion
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Bioremediation
• The use of naturally occuring microorganisms such as bacteria, fungi &
plants to break down or degrade toxic chemical compounds that have
accumulated in the environment
• It is a method that treats the soils and renders them non-hazardous, thus
eliminating any future liability that may result from landfill problems or
violations.
Factors affecting bioremediation
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Microbial factors
Temperature favorable for organisms
Availability of water (Moisture content)
Availability of nutrients (N,P,K)
C: N (carbon: nitrogen) ratio of the contaminant
material< 30:1
• pH
• Availability of Oxygen in sufficient quantity in soil.
Water pollution
• Water pollution occurs when harmful substances are released
into the water in large quantities which cause damage to
people, wildlife, or habitat or indirectly into water bodies
without proper treatment to remove harmful compounds.
Effects of water pollution
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Water pollution is a major problem
in the global context. It has been
suggested that it is the leading
worldwide cause of deaths and
diseases, and that it accounts for
the deaths of more than 14,000
people daily.
An estimated 700 million Indians
have no access to a proper toilet,
and 1,000 Indian children die of
diarrhea sickness every day.
Some 90% of China's cities suffer
from some degree of water
pollution, and nearly 500 million
people lack access to safe drinking
water.
Examples of water pollutant
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oil & grease from cars
fertilizers
animal waste
grass clippings
septic systems
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sewage & cleaners from
boats
household cleaning
products
litter
bonsai