SEMINAR ONSEMINAR ONMARINE POLLUTIONMARINE POLLUTION

CONTENTS• INTRODUCTION• MARINE POLLUTION• POLLUTANTS: SOURCES AND THEIR

EFFECTS• PREVENTION AND CONTROL OF MARINE

POLLUTION• CONCLUSION• REFERENCES

INTRODUCTION• Oceans cover about 71% of the

Earth’s surface.• They play an important role in the

chemical and biological balance of the life on the earth.

• They are vital to our food security, commerce and transportation.

• But human activity has troubled the health of oceans.

• The habitats of marine mammals and fish have been degraded severely, with pollution responsible for the mass deaths of fish, mammals and corals.

• Organochloric pollutants, pesticides, polychlorinated biphenyls (PCBs) and a range of other toxic pollutants accumulate within fishes later moving up the food chain to cause reproductive disorders.

MARINE POLLUTION• It is defined as the

discharge of waste substances into the sea resulting in harm to living resources, hazards to human health, hindrance to fishery and impairment of quality for use of sea-water.

• Marine pollution is associated with the changes in physical, chemical and biological conditions of the sea water.

POLLUTANTS: SOURCES AND THEIR EFFECTS

Pollutants can simply define as the materials which cause pollution. The following are the important pollutants that cause the marine pollution.

• Sewage• Pesticides• Plastic wastes• Metallic wastes• Oil• Sediment plumes (by deep sea mining)• Heat• Radioactive waste• Dredge spoil

SEWAGE Sewage may be entering the

sea– By direct drainage – From inland towns and

industries.– Tipping at sea from ships.

Detrimental effects of sewage include – Eutrophication– Deoxygenation– Foul deposits, Reduced salinity,

Infection and toxic residues,

PESTICIDES• Pesticides are organically active

chemicals which are used for killing the pests.

• Pesticides may enter the oceans – From the atmosphere after aerial spraying, – From overland runoff of sprayed areas.– From intentional dumping in the sea.

• Pesticides affects food chain directly. • These are more and more

concentrated in fish, seagulls, seals, penguins and marine planktons.

• PCBs have been found to have a series effect on this aquatic animal’s reproductive cycle. And known to cause patches on the skin, immunotoxicity, kidney damage, weight loss and tumor formation in otters.

PLASTIC WASTES• The mass of plastic in the oceans may be

as high as one hundred million metric tons.• Many animals that live on or in the sea

consume flotsam by mistake, as it often looks similar to their natural prey.

• Plastic debris, when bulky or tangled, is difficult to pass, and may become permanently lodged in the digestive tracts of these animals, blocking the passage of food and causing death through starvation or infection.

• Fishing nets entangle fish, dolphins, sea turtles, sharks, dugongs, crocodiles, sea birds, crabs, and other creatures, restricting movement, causing starvation, laceration and infection, and, in those that need to return to the surface to breathe, suffocation.

METALLIC WASTES• Metallic chemical elements have a relatively

high density and toxic or poisonous at low concentrations. Examples are mercury, lead, nickel, arsenic, cadmium and so on.

• Metallic wastes can be enter the marine environment naturally – through weathering of the earth’s crust. – from rivers or by direct discharges.– through the atmosphere also. – These can enter the sea through oil spill

also.• The use of antifouling paint on the bottoms of

boats has been implicated as a major source of heavy metals in waters.

• These toxic metals can accumulate in the tissues of many species of aquatic life.

• When we consume such fishes, it will affect our nervous system, kidneys, brains, respiratory system or even it will lead us to death.

OIL Oil may enter the sea water by number of

ways as follows;• Cargo tanker washings at sea and international

discharge of oily wastes from tank washings and accidental spillages pollute the sea water severely.

• Bilge pumping at sea• Import oil losses: collisions in port• Tanker accidents and maritime accidents due

to collision, fire, explosion or grounding also result in oil release in water.

• Oil leakage from pipelines• The blowout of wells, disposal of drilling mud,

accidental damages to offshore drilling rigs add to oil pollution in water.

• Oily wastes from oil fields or refineries near the coast.

• Oil spills mixed with urban sewage, silt, plastics, pesticides and insidious toxic compounds are pervasive and complex the pollution problems in sea.

Oil pollution in Gulf of Mexico

An Oil Slick from a Satellite

OIL The overall detrimental effects of oil pollution sea

water are as follows;• Reduction in dissolved oxygen.• Reduction in light penetration.• Oil spilling causes lethal toxicity to aquatic flora.• Smothering coats of oil have killed lichens and

algae along the shore lines.• Sea otters will die when their fur become saturated

with oil by losing insulation.• Waste from oil refineries and discharged petroleum

from ships cause heavy damage to fishery.• Hydrocarbons in oil get incorporated in body

tissues of marine animals. • When the concentration of crude oil in the sea

water reaches 0.02ppm, fish eggs begin to hatch irregularly or late, while the development of already-hatched young fish or larval crabs and lobsters becomes abnormal at oil concentrations between 1 and 100ppm.

• When men consume the fishes from oil polluted sea water, it may result in breathing problems, and can damage liver and kidneys.

SEDIMENT PLUMES(BY DEEP SEA MINING)

• Because of deep sea mining, the removing parts of the sea floor, disturbs the habitat of benthic organisms.

• Plumes are caused when the tailings from mining (usually fine particles) are dumped back into the ocean, creating a cloud of particles floating in the water.

There are two types of plumes:

• Near bottom plumes• Surface plumes

HEAT• Accumulation of unusable heat from

human activities can disrupts ecosystems in the marine environment.

• The most important sources of thermal marine pollution are the nuclear power plants and Thermal power plants.

• These power plants use the sea water for cooling. This water is generally returned to the sea at temperatures 11 to 220C (20-400F), which is higher than it was initially.

• One nuclear power plant may use as much as one billion gallons of sea water per day.

• Marine life is extremely sensitive to changes in water temperature. Higher temperatures can lead to premature spawning, fish migration, lack of oxygen or death of marine life.

RADIOACTIVE WASTE Radioactive materials enter to the

oceans mainly from following ways:-• From natural background source:• From fallout of nuclear weapons testing.• From operation of nuclear reactors

through intentional and unintentional direct releases.

• Mining and processing of ores to produce radioisotopes.

• Emission from the industrial use of nuclear energy.

• Leakage from underground nuclear detonations.

• From shipboard reactors. Radioactive contaminate sea water will

consumed by plants during photosynthesis acts as a medium for radioactivity in them. By this, radionuclide enter into the food chain of marine water.

• When men consume these radionuclide fishes, it will cause cancers, leukemia, eye cataract, DNA breakage and carcinoma in humans.

DREDGE SPOILS• Dredge spoils constitute the greatest

pollutant input by volume to the oceans. Spoils from dredging or mining of offshore minerals are deposited within a few miles of shore, where the potential impact is the greatest.

• Often they also contain sewage or industrial waste solids and solids from street runoff. Consequently, they often contain objectionable amounts of hazardous chemicals, pathogens, or oil and may exert a high oxygen demand on the surrounding environment.

The damage which can be caused by dredging is two fold:1. That occurring at the dredging

site, and2. That occurring at the dredge

spoils disposal area.

PREVENTION AND CONTROL OF MARINE POLLUTION

• Stabilization of the ecosystem• Reutilization, recycling, renovation and

recharge of the waste• Removal of the pollutants• To control the oil pollution, following

methods are used– Skimming– By spreading a high density powder

over the oil patch, it can be sunk to the bottom.

– Biodegradation– Burning– Using a suitable absorbing material.

• Heat can be removed from condenser cooling waters prior to their disposal into the marine water.

PREVENTION AND CONTROL OF MARINE POLLUTION

• Removal of phosphorus by electrolysis.• Adopting appropriate methods to remove

heavy metals from the marine water.• Radioactive wastes can be removed or

reduced by the ion-exchange techniques, precipitation of radio-nuclides.

• The impacts of deep sea mining can be minimize or reduced by using proper mining techniques.

• Creating awareness on marine pollution.• Local communities near sea must protect sea.• Management by government • Incentives must be offered for conservation. • Industrial units should be equipped with

pollution control instruments.

CONCLUSION• Oceans cover the earth’s surface about 71% and play

an important role in the chemical and biological balance of the life on the earth.

• These are rich with marine resources like minerals, oil and marine life and the sea food supplies meet a substantial food requirement of the world’s population.

• If the marine life affected by the pollution and if they carry pollutants in its biomass, the human population may get the impact while consuming such resources. Hence it is necessary to aware about the marine pollution, and to protect the marine water from the pollutants. So, necessary to prevent and control this pollution.

• Let us save our oceans and the huge marine ecosystem.

REFERENCESBOOKS• Asha Rao S. N.(2004), Environmental studies, Chethana book house, pp:128-130• A K Tripathi, A K Srivastava and S N Pandey (edited , 1993), Advances in environmental sciences, Ashish

publishing house, pp:93-109• B K Sharma(6th edition, 2001), Environmental chemistry , Goel publishing house, Meerut, pp:64-74• D K Kumarswamy, Mr. A. Alayappa modes, Dr. M Vasanthy(1st edition, oct,2004), Environmental studies,

Bharathidaran University, Tiruchirapalli, pp:142-145• K. Siddhartha(1999), Oceanography, a brief introduction, Kisalaya publishing pvt ltd, pp:310-314• Paul. L. Bishop(1983), Marine pollution and its control , McGraw-Hill Book Company.• P K Goel (2000), Water pollution: causes, effects and control, new age international (p) ltd.WEBSITES• www. wikipedia. org.• www. geology.com• www. ask.com• www.oeceanimages.com• www.earthobserver.org• Google images• www.mcsuk.org/marineworld/pollution.html• www.worldstats.org/general_world/principal_environmental_treaties.html• www.cmc-ocean.org• www.oceanlink.island.net/ask/pollution.html

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