Chemistry topics 1.1.MAY.2014 | Page 7

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CARING WATER, A VITAL RESOURCE

Rainwater in the storm drainage system, major pollutants

Storm drains are a huge source of water pollution in the. Few people know that washing dirt and pollutants off driveways, over-fertilizing their lawns, and dumping debris directly into storm drains helps to pollute local waterways and ocean areas.

Toxics, such as oil, antifreeze, and pesticides reaching our water ways and coastal areas can kill fish and other wildlife, and even inhibit their ability to reproduce. Some toxics can remain in stream, bay, and ocean sediments for generations.

Fertilizer contains large amounts of nitrogen and phosphorous, which can cause harmful algal blooms in waterways and the ocean that rob water of oxygen and light—both of which are essential to supporting life. Nitrogen carried down the Mississippi from midwestern farms, for example, has caused a “dead zone” in the Gulf of Mexico that is the size of Massachusetts. No fish or plants can survive in such an environment.

Debris and litter is more than an eyesore—it is dangerous to humans and to wildlife.

Plastic strapping and six-pack holders can strangle or entangle wildlife. Many birds are indiscriminate eaters, and they can ingest small pieces of plastic and other debris,which can eventually kill them. Scientists estimate that more than one million birds and 100,000 marine mammals and sea turtles die each year as a result of entanglement in,

or ingestion of, marine debris.

Atmospheric pollutants

Sulfur oxides (SOx), Nitrogen oxides (NOx), Carbon monoxide (CO), Volatile organic compounds – VOCs, Ammonia (NH3), Odors, Radioactive pollutants, etc.

Urban pollutants

Water running off these impervious surfaces tends to pick up gasoline, motor oil, heavy metals, trash and other pollutants from roadways and parking lots, as well as fertilizers and pesticides from lawns. Roads and parking lots are major sources of polycyclic aromatic hydrocarbons (PAHs), which are created as combustion byproducts of gasoline and other fossil fuels, as well as of the heavy metals nickel, copper, zinc, cadmium, and lead. Roof runoff contributes high levels of synthetic organic compounds and zinc (from galvanized gutters). Fertilizer use on residential lawns, parks and golf courses is a measurable source of nitrates and phosphorus in urban runoff when fertilizer is improperly applied or when turf is over-fertilized.