Tundi Agardy, Ph.D.
Introduction
The world ocean provides important health benefits to humans, ranging from food, nutritional, and other resources, to recreational opportunities, to support for industries, to better understanding of human physiology, and new treatments for human disease. However, as oceans become more degraded, human health effects from exposure to dangerous substances, including synthetic organic chemicals, polycyclic aromatic hydrocarbons, heavy metals, marine toxins, and pathogens have been increasingly recorded and are now of great concern3. Coastal and marine habitats that have been negatively impacted by human use and development are unable to provide goods and services, and add to the human health risks posed by degraded oceans. Degraded seas thus move from being great providers to becoming threatening to human health. The result: increased rates of starvation and poverty, diminished sanitation and hygiene, accelerated spread of disease and poisoning, beach closures and reduced access to ocean areas, and ever-increasing public health costs and societal conflict.
Oceans suffer from being downstream, of everything. All our chemical inputs, unused fertilizers, pesticides and herbicides, debris, eroded silt and topsoil, untreated sewage, medicines -- from our farms, our factories, our suburbs, and our cities -- eventually make their way to the world ocean. As a result, coastal seas are now described as the most chemically altered environments on earth. Pollutants reach the seas via river inputs, atmospheric deposition, and run-off, resulting in expanding dead zones and endangering fisheries, biodiversity, and human health.
The indirect degradation of oceans is an increasing problem, despite government regulations on pollutants. This is partly due to the fact that the ocean system’s most vital organs: the coastal wetlands, seagrass beds, and mangrove forests that are its lungs, liver and kidneys, filtering out toxins before they reach the open sea, continue to be destroyed through coastal development. Added to these insults is the growing clamor of global warming – once white noise, now a startling catastrophe building on the horizon.
The story of how human health and ocean health are related is not one easily told, which is why this may be the biggest sleeper issue of all. How much easier to portray the plight of the great whales, or to document the decline in fisheries, or to show a coastline sullied by unsustainable development. Pollution is difficult to see, even harder to trace, sometimes ephemeral, but with long-lasting impacts. Eutrophication – the over-fertilization of nearshore waters caused by too many nutrients from fertilizers, sewage, animal waste, food processing residues – threatens to disrupt the ecological balance of coastal areas around the world. At the same time, toxins enter the marine system, are distributed worldwide by ocean circulation, and reside everywhere for long periods – until they are actively removed by mitigation (or until they enter the human food chain, leaving the marine environment to reside in our own tissues).
That degraded oceans are endangering our health is not widely acknowledged. The reason has in part to do with the way we gauge the condition of the world’s ecosystems – especially those which are remote or understudied, as all marine ecosystems are. We have been far too long preoccupied with structure, measuring our impacts on forests, say, with loss of forest cover. But the health of the ocean is wearing down with precious few outward signs of change. Our preoccupation with structure has caused us to focus our limited resources and energies on places which may be functionally less important than others; this same preoccupation has made us miss the warning signs of deteriorating ocean health until crisis points have been reached.
Yet the recent and in some cases precipitous decline in the health of the oceans has made the linkages more conspicuous to scientists, and even to some policy makers4.
3 Dewailly, E. et al., 2002. Indicators of ocean and human health. Can. J. Public Health 93:S1:S34-38.
4 Knap A, Dewailly É, Furgal C, Galvin J, Baden D, Bowen RE, et al. 2002. “Indicators of ocean health and human health: developing a research and monitoring framework,” Environmental Health Perspectives 110:839-845; see also Verlaan, P.A. 1997. “The Importance of Coastal Management to Human Health: Toward a Sustainable World,” International Perspectives on Human Health, G.B. Shai et al., [eds.] Springer Publishing, NY
