Soil pollution

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Transcript Soil pollution

Soil, marine ,noise and
thermal pollution
Soil
• Formation of soil from the parent material (bedrock):
mechanical weathering of rocks by temperature
changes, abrasion, wind, moving water, glaciers,
chemical weathering activities and lichens.
• Under ideal climatic conditions, soft parent material
may develop into 1 cm of soil within 15 years.
• O-horizon: freshly-fallen & partiallydecomposed leaves, twigs, animal
waste, fungi & organic materials.
Colour: brown or black.
• A-horizon:
humus/partially
decomposed organic matter & some
inorganic mineral particles. darker &
looser than the deeper layers.
• O & A-horizon: contain a large
amount of bacteria, fungi, earthworms,
small insects, forms complex food web
in soil, recycles soil nutrients, &
contribute to soil fertility.
• B-horizon /(subsoil): less organic
material & fewer organisms than Ahorizon.
• C-horizon: consists of broken-up
bedrock, does not contain any organic
materials. Chemical composition helps
to determine pH of soil & also
influences soil’s rate of water
absorption & retention.
• R-horizon: The unweathered rock
(bedrock) layer that is beneath all the
other layers
Soil Pollution
Soil pollution is caused by the presence of chemicals or other
alteration in the natural soil environment.
Resulting in a change of the soil quality
likely to affect the normal use of the soil or endangering public
health and the living environment.
CAUSES OF SOIL DEGRADATION
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Soil erosion/degradation is the loss of top soil
erodes fertility of soil & reduces its water-holding
capacity.
Excessive farming, construction, overgrazing,
burning of grass: cover and deforestation
Excess salts and water (Salinization)
Excessive use of fertilizers & pesticides
Solid waste
First effect of pollutants
• Washed away: might accumulates somewhere
• Evaporate: can be a source of air pollution
• Infiltrate through the unsaturated soil to the
groundwater
• DDT: fat soluble, stored in fatty tissues
– Interferes with calcium metabolism
– Results in thin egg shells in birds
• Agent orange: code name for one of the herbicides
and defoliants (results in leaf fall) used by the U.S.
military as part of its herbicidal warfare program, During
the Vietnam War, between 1962 and 1971, the United States military
sprayed 20,000,000 US gallons (80,000,000 L) of chemical herbicides
and defoliants in Vietnam
– anti fertility, skin problems, cancer
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
• Afforestation and reforestation.
• 3 Rs: reduce, reuse, recycle
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Information needed to clean up materials added to soil
Kind of material-organic or inorganic- is the material
biodegradable/ dangerous to animals & humans
 How much material was added to the soil, will it overload
the organisms in the soil
C:N ratio of the pollutant material
Nature of soil: will the soil be able to handle the material
before groundwater is contaminated
Growing conditions for the soil organisms: - is it too cold,
too wet etc.
How long the material has been on site: is there evidence
of environmental problems, is it undergoing decomposition.
Immediate danger to people & environment: Urgency of
the situation.
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.
• In situ Bioremediation : The treatment in
place without excavation of contaminated
soils or sediments.
• Ex situ bioremediation: requires pumping
of the groundwater or excavation of
contaminated soil prior to remediation
treatments.
Types of In situ Bioremediation
• Biostimulation: To stimulate the activity of microorganisms
by adding nutrients and electron acceptors (e.g. O2)
• Bioventing: Injecting air through soil to stimulate microbe
growth in unsaturated zone
• Biosparging: Injection of air/nutrients into unsaturated and
saturated zones
• Bioaugmentation: inoculation of soil with microbes or
adding exogenous microbes to the subsurface
In-situ-Bioremediation
Good for large volumes
Slower
Doesn’t work well in clays or
highly layered subsurfaces
• Biostimulation (stimulates
biological activity)
– Bioventing (Inject
air/nutrients into
unsaturated zone – good
for midweight petroleum,
jet fuel)
– Biosparging (Inject
air/nutrients into
unsaturated and
saturated zones)
• Bioaugmentation (inoculates soil
with microbes)
Less expensive
• Creates less dust
• Less possibility of contaminant
release into environment
Biostimulation
Biosparging
Ex-situ -Bioremediation
• Slurry-phase-Soil combined with
water/additives in tank,
microorganisms, nutrients,
oxygen added
• Solid-phase
– Land-farming: soil put on pad,
leachate collected
– Soil biopiles: soil heaped, air
added
– Composting: biodegradable waste
mixed with bulking agent
– Land Applied –waste added
directly to soil which is later
planted to a crop.
•Easier to
control
•Used to treat
wider range of
contaminants
and soil types
•Costly
•Faster
Advantages of Using Bioremediation Processes
Compared With Other Remediation Technologies
(1)
biologically-based remediation detoxifies hazardous substances
instead of merely transferring contaminants from on environmental
medium to another;
(2) bioremediation is generally less disruptive to the environment than
excavation-based processes; and
(3) The cost of treating a hazardous waste site using bioremediation
technologies can be considerably lower than that for conventional
treatment methods: vacuuming, absorbing, burning, dispersing, or
moving the material .
Marine pollution
• The introduction by man, directly, or indirectly, of
substances or energy to the marine environment
resulting in deleterious effects such as: hazards to
human health, hindrance to marine activities, impairment
of the quality of seawater for various uses and reduction
of amenities.
• Does not include natural processes like volcanic
eruptions or earthquakes
Marine pollutants
• Agricultural run offs ((herbicides, pesticides and
nutrients)
• Sediments
• Sewage (Faecal Coliform and Pathogens)
• Chemicals, Metals and Radioactive Substances
• Persistent toxins (PCBs, DDT, heavy metals)
• Oil
• Plastics
• Energy (Thermal & light)
Sources of marine pollution
Land sources
• 80% of non-biological marine pollution comes from land based
activities
• pipes discharging directly into marine waters(sewage,
industrial, chemical and food processing wastes)
• Riverine flows into the sea carry pollutants from the entire
catchment area.
From Air
• Global atmospheric inputs to the sea from air discharges
Oil spills and offshore sources
• Oily discharges from ballast water and bilge water during
routine ship operations and illegal dumping of solid waste
• Designated dumping grounds at sea
• Accidental spills from Ships carrying hazardous substances, oil,
gas etc.
Control measures for oil pollution
• Natural process of emulsification of oil by
use of chemical dispersants: can be
sprayed on the oil.
• Slick-lickers: continuous belt of absorbent
material dips through the oil slick & is
passed through rollers to extract oil.
• Rocks can be cleaned with high pressure
steam
Effects of marine pollution:
• Effects on sea life
• Effects on birds
• Effects on human being
– Health
– Business
• Eutrophication and development of red tides (phytoplankton
blooms carrying red pigmentation)
• Development of oil slick: When oil is spilled on sea, it spreads
over the surface forming a thin film called OIL SLICK. Which
damage marine life
Effects of marine pollution
• Damages marine life to a large extent, for salt-marsh
slicks can affect flowering, fruiting and germination.
plants, oil
• Coral reefs
• If liquid oil contaminates a bird’s plumage, its water-repellent
properties are lost, drown, die
• Drill cuttings dumped on seabed create anoxic conditions & result in
the production of toxic sulphides in the bottom sediment thus
eliminating the benthic fauna.
• Fish and shellfish production facilities can also be affected by oil
slicks. Commercial damage is tainting: imparts an unpleasant flavor
to fish and seafood & is detectable even at extremely low levels of
contamination.
NOISE POLLUTION
• Defined as unwanted sounds that
unreasonably (a kind of harsh, loud and
confused sound), intruding into our daily
activities
• The most significant attributes of noise are:
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Its loudness
ii) Duration
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The unit of noise is decibel.
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Human ear can tolerate noise up to 120
decibels.
Sources of NOISE POLLUTION
(i)
Road Traffic:
Most prevalent and most damaging source
Impact of road traffic noise depends on factors like: road location & design, and land use
planning measures, building design, vehicle standards & driving behavior
(ii)
Air Traffic
Noise from supersonic crafts are dangerous because of its intensity
(iii)
Railways:
The level of noise associated with rail traffic is related to type of engine or rolling stock
used, speed of the train, track type & condition, warning signals at crossings, whistles &
horns, freight classification yards, & railroad construction & maintenance.
(iv)
Industry
• Product fabrication
• Product assembly
• Power generation
• Processing.
(v) Construction: construction equipments.
(vi) Consumer products: recreational, hobbies/workshop, household, music.
(vii) Other sources: sirens, agricultural noise, noise from animals, humans & military
Measurement of Noise
• Noise intensity is measured in decibel (Db) units
• Decibel scale is logarithmic,
• Each 10 Db increase represents a 10 fold increase in
noise intensity
• distance diminishes the effective decibel level reaching
the ear.
e.g. Moderate auto traffic at a distance of 30 m rates
about 50 decibels, but for the same, for a driver with a
car window open or a pedestrian on the sidewalk, same
traffic rates about 70 decibels.
Effects of Noise
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At 45 decibels of noise, average person cannot sleep,
At 85 decibels hearing damage, & at 120 decibels ear
experiences pain.
Lack of sleep, irritability, heartburn, indigestion, ulcers, high blood
pressure, & possibly heart disease
Hearing loss
Non-auditory physiological effects
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Annoyance
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Communication interference
Noise Pollution Control
Source path receiver concept: Can be controlled either
by reducing the noise at the source or by preventing
its transmission or by protecting the receiver
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At the source: lubrication of machines, tightening the
loose units, reducing the eccentricity
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In the path: keeping the noisy machine covered,
construction of noise barriers, sound-proofing of the
building
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Receiver: No use of horns other than in emergency,
vehicle engines and appliances in good Condition,
purchase the least noisy air conditioner or vacuum
cleaner/quieter appliances, rest areas away from
noise, turn down volume of Stereos.
Thermal Pollution
• Thermal pollution is the process of heating up of water
bodies through run off or discharge
• Decreases the solubility of oxygen, resulting in suffocation
of plants and animals
• Human activities introducing thermal pollution:
 Industries and power plants
 Trees and tall vegetation providing shades are cut down
 Soil erosion by construction, removal of stream side vegetation,
farming practices, overgrazing & recreation increases – reduction in
green
 Thermal pollution can also occur through Earthquakes
Effects of Thermal Pollution
• Thermal shock
• Thermal enrichment: Heated water from power plant
may be used to extend plant growing season, speed up
growth of fish and other aquatic animal for commercial
purpose