Most marine pollution around Trinidad and Tobago results from land-based sources. Marine pollution is defined as 'the 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'.

Heightened economic and social development, coupled with the growing demands of an increasing population, contribute to our islands' environmental degradation, particularly in the marine and coastal areas. Development in the business, industrial and tourism sectors in Trinidad and Tobago is proceeding at a rapid rate. In spite of being a small island state, we are at present the largest producer of ammonia in the world and the second largest producer of methanol. In addition to this, the islands of Trinidad and Tobago are increasingly in demand as tourist destinations, with yacht arrivals at Chaguaramas almost tripling over the last five years.

Land-based marine pollution arises from domestic, agricultural, industrial and municipal sources. Domestic wastes are normally associated with residential areas and housing developments, and include raw sewage (containing bacteria), solid wastes such as glass and plastic products, aluminum cans, styrofoam containers and general household wastes, including organic wastes.

Agricultural waste products include fertilizers and pesticides (washed into rivers from treated crops and fields) and liquid effluents containing high organic loads. In addition, animal husbandry (cattle, pig and poultry farming) contributes to the sewage content entering the sea via drains and rivers, the latter being the main channels whereby the land-based wastes enter the sea. Industrialized areas generate an array of wastes in significant quantities. These include a variety of chemicals from specific industries, lubricating oils, water treatment wastes, solid wastes, and cooling water, which may result in elevated water temperatures in the sea areas where it is discharged.

Unfortunately, Trinidad's rivers are also popular dumping sites for a variety of domestic garbage. The sight of old appliances, bags of chicken feathers, or discarded tyres in river beds and ravines is not uncommon.

Much of the garbage that is at the roadside or thrown out of car windows is eventually washed into drains and thence to the sea. This debris may float for a while, finally landing on some distant beach, or be mistaken for food by marine animals - birds, turtles or fish - often with fatal results.

Tourism and the use of resources by locals also contribute to land based pollution, by virtue of increased populations in many coastal areas of Trinidad. In areas like Chaguaramas, a significant increase in population is causing a direct increase in the volume of sewage to the system, which is already overloaded. The old sewage systems located in this area are non-functional and result in raw or untreated sewage entering the sea. In much the same way, hotel sewage wastes are directly linked to tourism; in Tobago, fragile marine resources such as coral reefs ad their associated fisheries are being affected negatively by increased quantities of sewage wastes entering the nation's seas because of insufficient and/or inadequate sewage treatment.

Marine organisms may be adversely affected directly by chemicals and solid wastes and as a result some species may die out. Sewage can act as a fertilizer leading to eutrophication and prolific algal growth and red tides. This may overwhelm marine organisms by causing oxygen depletion, or by actual physical clogging of the gills, resulting in massive fish kills, as have been documented for areas in the Gulf of Paria. The destruction of mangrove swamps and wetlands eliminates the breeding and nursery grounds of many commercially important fish and shellfish. The destruction of coral reefs, as has occurred at Buccoo in Tobago, affects the natural breeding and nursery grounds of young reef fish, such as groupers, angelfish and some sharks.

Human health may be directly or indirectly affected by these contaminants. The ingestion, for example, of contaminated seafood (fish and shellfish), as often occurs during the wet season in Trinidad, can cause bacterial and viral infections resulting in vomiting and/or diarrhea. Swimming in contaminated seawater may result in similar problems as well as skin and eye infections. In addition, the ingestion of seafood contaminated by heavy metals such as mercury, lead and zinc may lead to poisoning. In this respect, the use of anti-fouling boat paints, especially those containing copper, should be monitored.

Trinidad and Tobago must reduce the volume of land-based contaminants reaching the sea around it, if its present course of development is to be sustainable. The choice is clear. In order to reduce the volume of land-based contaminants reaching the sea, more effective enforcement of the legislation that already exists is required. Public education that encourages a better understanding of and appreciation of, biological diversity and the importance of conversation is necessary. People of all ages and backgrounds need to be aware of the far-reaching effects that the choices we make in our daily lives can heave. We need to understand that in the end, it all comes back to us.

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