An Introduction to Marine Pollution
What do we really mean when we talk about marine pollution?
A trip to the beach soured due to a beach closing. Warnings not to eat the fish because of potential toxins. Stories in the media about shorebirds and marine mammals endangered because of an oil spill. The general term for all types of related incidents is marine pollution. Here's a brief guide for defining it and exploring different types.
For close to thirty years, most academics studying the phenomena of marine pollution have adhered to a definition developed by a UN body, the Group of Experts on the Scientific Aspects of Marine Pollution (GESAMP), who define it as the,
"Introduction of man, directly or indirectly, of substances or energy into the marine environment (including estuaries) resulting in such deleterious effects as harm to living resources, hazard to human health, hindrance to marine activities including fishing, impairment of quality for use of sea-water, and reduction of amenities."
The definition has two important qualities. First, it is action oriented. Marine pollution is conceptualized as a human activity, thereby omitting all natural activities that could potentially have damaging effects on the ocean eco-system. So, for example, earth quakes or volcanic eruptions that emanate from the ocean floor and subsequently damage or change already existing ocean eco-systems would not be considered pollution.
Second, the definition is amenable to measurement. Marine pollution is harmful, and its danger can be identified in a variety of ways. For example, it is easy to see the deleterious effects that oil spills have on the sea birds and marine mammals who happen to run into them.
Scientists can also readily identify various toxic substances found in the marine environment, measure their quantities, and provide estimates of their potential danger for the health of both marine life and humans.
Probably the easiest way to think about marine pollution is to consider it in terms of its source. All marine pollution must originate from one of two sources, the land or the sea. Of course, because marine pollution is defined as a human activity, and humans are land creatures, it might be semantically correct to assert a land based origin for all marine pollution. Additionally, the acid rain phenomena suggests that air based sources of pollution are equally important. Semantics aside, differentiating between land and sea based marine pollution captures the core of marine pollution sources.
The sources of marine pollution can be broken down into the five categories:- land based sources contribute forty four percent to the total amount of marine pollution
- air based contributions total thirty three percent
- maritime transportation (which includes accidental and purposive oil spills, and dumping of ship garbage etc.) totals twelve percent
- dumping (which includes all other purposive dumping such as when a garbage barge goes to sea for the express purpose of dumping its load) represents ten percent of the total
- offshore production (the pollution coming from oil platforms etc.) represents one percent of the total.
© 2001-2005. Patricia A. Michaels.