Evil-smelling effluent bubbling from a factory into a bay. Is that what you see when you think of water pollution?
Twenty years ago, that picture would have been pretty accurate. But factories and municipalities have largely cleaned up their act -- and their effluent, the technical term for waste water.
Now when it comes to polluting surface waters, the biggest villains are us. You, me, Mr. Perennially Tinkering Under Cars next door, Ms. Weed and Feed the Lawn Every Month Whether It Needs It or Not on the corner, and the folks across the street who paved their yard so they wouldn't have to mow it.
The problem is runoff. When rain falls on forests and fields, it soaks gradually into the ground. Roots and soil filter the water as it trickles slowly downward to surface or underground streams. When that same rain falls on cities and suburbs, it splatters onto asphalt and concrete, lawns and construction sites. It picks up oil, gasoline, cigarette butts, fallen leaves, fill dirt and lawn-care products. It collects in dirty gutters, gathers in storm drains and washes downward -- untreated -- into the nearest bay, lake or stream, carrying thousands of pounds of toxic material with it.
Experts call this "non-point" pollution, because it comes from hundreds of small, hard-to-pin-down sources, rather than one large factory squatting over a stream.
The single biggest runoff problem is organic waste -- that is, grass clippings, leaves, garbage and feces from dogs and cats. This organic waste smothers fresh waters, robbing them of oxygen and killing aquatic life.
Each little bit contributed by each little yard adds up quickly. One study measured organic waste in runoff from the Washington area into the Potomac and Anacostia rivers (and eventually into Chesapeake Bay) in one 10-month period in 1989. The grand total? More than 25 million pounds of the stuff, including 7.2 million pounds of pet waste.
The result of all this dirty runoff is dirty water. That means contaminated shellfish beds, dead fish, excessive algae growth, toxic tides and, ultimately, lifeless waters. It is a pretty grim picture. But it has a brighter side. This kind of water pollution is one of the big environmental problems that each of us really can help alleviate. The place to begin is literally in your own back yard.
* Sweep or rake grass clippings from sidewalks, gutters and driveways. They aren't a pollution problem left on soil or grass. But left on concrete, they eventually wash into storm drains.
* Fertilize your lawn cautiously. Call the cooperative extension service in your area to find out how much and how often you need to fertilize. Excess fertilizer simply washes into surface waters, which are already overburdened with plant food.
* Use minimal pesticides or, better yet, don't use any at all. Pesticides and herbicides may persist for a long time in the environment. They wash off your garden and can poison fish and other aquatic life.
* Point downspouts onto grass or onto flower beds that can absorb and filter the water. Keep as much of your property in plantings as you can, avoiding impermeable patios, huge driveways and so on. If you must pave, look into getting the newfangled, porous asphalt. Water seeps through it.
* Control erosion of uncovered soil during construction or relandscaping projects by covering it with straw or hay. Don't use plastic. It's impermeable.
* Carry a pooper scooper or a plastic bag when you walk your dog, and use it. Pet waste should be disposed of in the toilet.
* Recycle your used motor oil and anti-freeze. Never pour it down storm drains. Carefully drain it from your car into a clean container. Call your local trash utility to find out where you can take it to be recycled. If you have a leaky crankcase or transmission, get it fixed. If it's not fixable, or if you can't afford to have the work done, keep a drip tray under the car when it's parked, and recycle the fluid.
* Keep your car tuned to reduce emissions. Particulates and other pollutants in the exhaust wash out in rain or settle on the ground and are picked up in runoff. This may seem rather far-fetched. It's not. Experts estimate that as much as 30 percent of the nitrogen fertilizing the Chesapeake Bay is from car exhaust.
The list is a lengthy one, and it won't be squeezed into a single newspaper article. But you get the idea. Rainwater washes off our cities and dirties our waters. Anything you leave on the ground or pour down a storm drain will be bobbing in the nearest lake, river, bay or stream sometime soon.