Although vessel source pollution is a serious threat to the marine environment, it should not be exaggerated. The 80% of marine pollution are those which originate on shore and eventually find their way into the sea (Bowman, 1996). The most common types of pollutant entering the sea from land are sewage, industrial wastes from manufacturing, and agricultural pesticides and fertilizers that are washed off the land. These substances usually find their way into the sea through rivers, but a significant amount of land-based marine pollution comes from dumping wastes at sea and through air pollution that is deposited into the oceans in the form of rain (Anton, 1996).
             The 1990 GESAMP report highlighted the diverse nature of the land-based threat to the marine environment. It concluded that this type of marine pollution had significantly worsened since 1982 and that sewage disposal and agricultural runoff of fertilizers and pesticides were the most urgent problems requiring international attention. The report also concluded that land-based pollution was no longer confined to coastal waters, but that some of the toxic substances from these sources are now resulting in
             ...