Sea water pollution

Seawater Pollution:

It is polluted mostly near the coast through the disposal of urban and industrial waste matters into the coastal waters.

  • Discharge of sewage, industrial effluents and toxic chemicals from urban areas and industrial establishment.
  • Discharge of solid waste materials mainly plastics, microbeads, etc. According to UNEP, plastic accounts for 90% of all debris floating in the oceans.
  • Leakages of enormous quantity of mineral oil from oil wells and tankers. Ex. Ennore oil spill, Tar balls off Mumbai coast, Deep Horizon disaster, etc.
  • Ballast water discharge
  • Deep Sea Mining
  • Increase in the concentration of heavy minerals like lead, cadmium, chromium, nickel, etc.


Oxygen depletion/hypoxia: Increase in BOD due to eutrophication results in death of marine organisms. Ex. Planktons, mollusks, etc. According to Wilkinson Report: 1998 Red Sea coral bleaching was due to disproportionate growth of algal bloom.

The Great Pacific Garbage Patch:


Damage to marine biodiversity: Bottles, plastics choke fish, turtles, etc.


For example,

Case study of Chennai oil Spill off (Ennore Port):

  • 40 tonnes of oil spillage (INCOIS)
  • 74 km stretch affected including Marina beach, Pulicat Lake (Bird sanctuary), Pichavaram mangroves
  • Damage to coral reefs (Rainforest of the oceans)
  • According to Global Coral Reef Monitoring Network, 20% of corals ex. Chitales are threatened due to toxic chemicals, oil spillage, pesticides, heavy metals, etc. as they introduce pathogens and causes bleaching.
  • Acidification of oceans: It reduces calcium carbonate mineral affecting coral polyps, oysters, crabs, salmons, etc. in shell and fin formation.
  • Deep sea mining: Damage to the habitats of benthic organisms like octopus, mollusks, eelgrass, etc.
  • Effect on the food chain: Heavy minerals like nickel, chromium (6), cadmium and bio accumulate in fish and ultimately enters into human food chain (bio amplification). Ex. Minamata disease, DDT, etc.
Steps taken by Indian Government to reduce coastal pollution:


  1. The present government has provided subsidies to the farmers of Tamil Nadu for transition towards deep sea fishing instead of bottom trawling fishing.
  2. The Society for Integrated Coastal Management (SICOM) under the Ministry of Environment, Forest and Climate Change is developing 13 beaches for blue flag certification under the Unified Coastal Areas Management Program.
  3. Indian government has come up with Coastal Regulation Zone (CRZ) Rules.
  4. India has become a member of Ballast Water Management Convention under International Maritime Organization.
Issues related to controlling of seawater pollution:


  1. The two formidable problems in conservation is:

o   International character of marine resources and right of all countries for their use

o   High mobility of marine organisms.

  1. Lack of awareness among fishermen communities.
  2. Lack of finance, infrastructure and capacity with Coastal Guards.
  3. Absence of waste management facilities at the beaches.

Strategies to handle Oil Spillage:


1.       Oil spill modelling:

It provides a clear idea about oil movement and enhances the decision-making strategy for quick response.

2.       Mathematical models:

The generic model to predict the movement of oil and the habitat specific model for detailed trajectory and impact analysis on marine resources. (Ministry of Earth Sciences)

3.       Use of GIS in estimation:

Information on bathymetry, oil concentration and thickness, quantity of dispersed oil may be incorporated in the maps.

4.       Ecologically sensitive areas such as coral reefs, seagrass beds, mangroves, mudflats, and wildlife protected areas may be layered.

5.       Bioremediation Techniques: Use of oil Zapper and Oilivorous-S (TERI- The energy research institute) to degrade oil contaminants in-situ.

  1. Biostimulation and Bioaugmentation.
Steps for the conservation of marine resources:


Food Resource:

  1. The accurate estimation of the growth and mortality rate of marine organisms is a prerequisite condition to ensure their sustainable yield.
  2. Proper survey of fishing areas by applying Echo-sounder techniques, maintaining catch statistics, etc.
  3. Accurate prediction of future demand of fish for human food and animal feed.
  4. Proper knowledge of potential reserve
  5. Developing and enriching Mari culture, ornamental fishing, marine pasture, etc.
  6. Investments in Deep Sea Fishing instead of Bottom Trawling fishing.

International initiatives:

  1. Full implementation of the Paris Agreement (UNFCCC)
  2. Blue Carbon Initiative (UNEP+IUCN+UNESCO) for the conservation and protection of marine and coastal biodiversity is in the right direction.
  3. Coral Triangle Programme (WWF) around Indian coastal States.
  4. India should become a member of the LONDON Convention.
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