Runoff

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Most ocean pollution can be attributed to runoff. Often referred to as urban runoff, stormwater runoff and non-point source pollution, this type of pollution is rain and river water that collects land-based contaminants and flushes them down to the beach.

In urbanized areas, runoff pollution occurs when water washes off rooftops, roads, parking lots, baseball diamonds, construction sites, golf courses, lawns and other surfaces, carrying a wide variety of contaminants down to the ocean. Unlike sewage and industrial outfalls, urban runoff receives no treatment before entering the ocean. The United States Environmental Protection Agency (EPA) now considers pollution from all diffuse sources, including urban water pollution, to be the main contributor to the contamination of our nation's waters.

The pollutants in urban runoff are created from the following: vehicle use, roads, home landscaping and public grounds maintenance, construction sites, septic tanks, pets and wild animals, littering and landfills. Vehicle use contributes heavy metals such as lead, cadmium and arsenic from brake pad and tire wear as well as gasoline and oil from the engine. Landscaping contributes herbicides and pesticides; over-fertilizing can add nutrients that overload coastal aquatic systems and starve fish of the oxygen they need to breathe, resulting in dramatic fish kills -- where millions of fish can die in a single day -- and septic tanks, pets and wild animals contribute feces laden with bacteria and viruses to the ocean.

In rural areas, similar runoff problems are the result of rainwater flowing over farms, roads, golf courses and lawns into waterways that ultimately reach the beach. Agricultural runoff may contain high concentrations of animal waste, fertilizers and pesticides.

Stormwater runoff from both sources is a threat to human health and the health of coastal ecosystems. Surfers, swimmers and other ocean enthusiasts may be exposed to dangerous pathogens, bacteria and viruses that are believed to cause of gastroenteritis, hepatitis, respiratory illness, and ear, nose and throat problems. Coastal ecosystems suffer from overdoses of nutrients, heavy metals and sedimentation.

Urban and agricultural runoff can be reduced. In urban areas, land use planning that reduces impervious surfaces -- roads, pavement, parking lots -- will allow water to be absorbed into the ground and naturally filtered prior to running directly into the ocean. Protecting, enhancing and restoring wetlands improve nature's ability to filter polluted water. Citizens in urban areas can be educated to clean up after their pets, properly dispose of oil and other chemicals, and reduce the use of poisonous herbicides and pesticides. In agricultural areas, proper fencing, the use of natural buffer areas and the reduction of herbicide and pesticide use can reduce water contamination. --Chad Nelson