INTRODUCTION 

The Ocean covers approximately 70% of the earth\'s total surface area. In the total water content of earth, 97% is present in the Oceans. It harbours rich source of biodiversity, which population may exceeds in trillions. Oceans are the main regulatory agent of earth\'s climate. About 60% of the world\'s population live within 60 km of coastline and use the coastline for their livelihood. It was thought that human being, living only on one-third of the portion of globe, cannot pollute this vast amount of water, as the marine ecosystems are capable of serving as sink for all the pollution caused by us. However, in reality this is not true. We have come to realize that our waste, even in small quantities, have huge effects on ocean communities and species. More over, it is difficult to believe that something so massive and seemingly resilient can really be adversely affected by our activities. Environmental pollution of the coast, inshore water and deep ocean is one of the important topical issue in the context of human health and global warming. The major pollutants like oil, sewage, garbage, toxic chemicals, pesticides, heavy metal, radioactive waste, thermal pollution, and eutrophication in coastal and marine environments, their characteristics and principal impacts are discussed in detail.  

1. 1. Definition of Marine Pollution 

The term marine pollution was defined by United Nations working group called \"Group of Experts on Scientific Aspects of  Marine environmental Protection (GESAMP)\". GESAMP defined it as \"Pollution means introduction by man, directly or indirectly of substances or energy into the marine environment (including estuaries) resulting in such deleterious effects as harm to living resources, hazards to human health, hindrance to marine activities including fishing, impairment of quality for use of seawater and reduction of amenities\".  

1. 2. Why marine pollution is a concern? 

We should care about the continuing environmental degradation of our oceans and costal areas because it is detrimental to human health, economic development, climate and our planet\'s store of biodiversity. It is interfering with the sustainability of environment and its resources.  

1. 3. What is biodiversity? 

The biodiversity Convention - Article 2 states that \"Biological Diversity\" means the variability among living organisms from all sources including inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems\".  

1. 4. What is Sustainability? 

Sustainability can be defined as the development that meet the need of the present, without compromising the ability of future generation to meet their own needs.  

1. 5. Categories of man made effects 

Man\'s effect on the marine environment may be divided into the following general categories.  

1. Alteration of bottom substrate through degrading, changing of shoreline structures, and filling.  

2. Introduction of toxic substances dangerous either to marine life or to human beings  

3. Release of sewage rich in nutrients with marine microorganisms  

4. Heating and release of heated water by power plants  

To study the effect of a particular type of pollution or multiple type of pollution Environment Impact Assessment (EIA) are being made at needed location considering various parameters.

1. 6. Definition of Environmental Impact Assessment 

EIA is the systematic, reproducible and interdisciplinary consideration of the potential effects of a proposed action and its reasonable alternatives on the physical, biological, cultural and socioeconomic attributes of a particular geographic area. Also it is a decision making process designed to help integrate economic, social and environmental concerns and of mitigating the adverse environmental impacts of activities related to projects, plans, programs or policies.  

The effect of pollutant can be divided into long-term (chronic) and short-term (acute) effects. Chronic pollution involved in the introduction of a toxic substance or other anthropogenic factor, often continuously and in fairly low levels, causing degradation of the environment. Input of nutrients through sewage is a good example. In the short term inputs, it may have sharp effects, but these may dissipate with time. The oil spill in marine area is an example for the short term toxic input. Oil spill often has catastrophic effects on the marine biota when released. However, the effects may gradually reduce as the oil break down after a span of a considerable time.  

In chronic studies, the organism of interest is exposed to a low concentration of the contaminant such as heavy metal, pesticides, or oil for a significant stage of its life cycle or the entire life cycle (i.e. generally weeks to years depending on the reproductive life cycle of organisms). Typical effects of endpoints include reproductive  failure, growth retardation, development impairment, as well as behavioural changes. In acute studies, the organisms of interest is exposed to a low to lethal concentration of a contaminant such as heavy metal, pesticides or oil for only a small portion of its life cycle (i.e., generally less than four days). The effects of endpoints include mortality or immobility.  

1. 7. Marine pollution in the coastal zone 

The coastal zone is defined as \"The area extending from the coastal plains to the edge of continental shores, approximately matching the region that has been alternatively flooded and exposed during the sea level fluctuation of  the late quaternary period\" (Lociz Science Plan, 1998).  

In the earth\'s surface, 18% is represented by coastal  zone, which provide space for 60% of the world\'s human population. Because, 70% of the world cities with population exceeding 1.6 million are located in this zone. 

Interestingly, 90% of the world fish catch is obtained  from coastal zone. The coastal zone is only 8% in the hydrosphere, but responsible for 18-33% of the total primary production. The biological wealth of this zone is very high as it served as feeding, nursery and spawning grounds with rich biodiversity.