| The Magazine of the CALIFORNIA ACADEMY OF SCIENCES |
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HABITATS Clean Car, Dirty Bay
The grime on your car poses a significant threat to San Francisco Bay’s ecological health. According to a 2003 Bay Conservation and Development Commission report, what regulators call nonpoint source pollution (NPS) is poisoning the bay and its inhabitants, including you and me. In plain English, NPS is polluted runoff. It comes from fertilizer, pesticides, acid rain, dog and cat poop, the dumping of dirty oil into storm drains, and a zillion other “nonpoint” sources. Although the San Francisco Estuary Institute (SFEI) is trying to quantify the harmfulness of particular substances to the Bay’s organisms, data linking specific pollutants to specific effects is hard to come by. Studies of toxicity levels in bay fish, however, show dangerous amounts of mercury, dioxin, and PCBs in high concentrations. The levels are high enough the the Environmental Protection Agency (EPA) advises people to limit their intake of fish from the bay to twice a month. The biggest, most important contributors of NPS are cars and trucks: yours and mine. Our car habit is the Goliath squatting smack in the middle of our environmental living room, but as I’ve not yet found a working slingshot, this column focuses not on the entire giant, but on something more manageable—his hygiene. There are 90,000 car washes across the nation and we Americans spend $35 billion a year keeping our cars clean, according to the International Car Wash Association (ICWA). For comparison, the annual budget for the National Park Service is $1.67 billion, and the EPA’s 2004 budget totals less than $8 billion. Why are Americans so clean car obsessed? For most people the incentive is aesthetic or psychological, says Jeff Mitchell, director of marketing for ICWA, which studies such questions. Environmental concerns are not a big motivator when it comes to car washing, says Mitchell, but that doesn’t negate the fact that the way you bathe your beast may have a significant environmental impact. I’ve always cast a disapproving eye at gleaming cars, seeing them as a sign of misplaced priorities. I hate to surrender my sanctimony as much as anyone, but a little research reveals that Mitchell is right—a properly cleaned car is not as bad an environmental offense as a dirty one. Cars produce all kinds of toxic waste: in addition to their poisonous and climate-altering tailpipe discharges, they also shed lead and zinc from their brake linings and very fine rubber dust from their tires. They give off chromium, benzene, and asbestos, rust and oil. A lot of this crud ends up sticking onto other cars, constituting the coating that makes much of the dirt on a dirty car. But dirt is really too benign a word. If you collected your car’s coating of grime and packaged it, you’d have to get a toxic waste permit to transport it. But as long as this grime stays on your car, it’s legal, and provided you don’t ingest it, it’s relatively safe. The trouble begins when it rains: the toxic stuff runs off the car and onto the street, into the storm drain, and, untreated, out to creeks, bays, or the ocean. The same happens when a car is washed in the driveway or on the street. Except worse, because washing adds phosphate-laced detergents, dyes, acids, chlorine, and ammonia from the cleaning solutions to the toxic grime. All this goes down the storm drain and straight back to nature. Downstream, hundreds of gallons of water become poisonous to the fish, invertebrates, and other creatures that live in it. Nonpoint source pollution worsens with the expansion of cities and suburbs as roads, buildings, parking lots and other impermeable land uses cover more and more ground. When rainwater soaks into permeable earth it percolates and filters slowly back to the water supply. In heavily paved urban and suburban areas, rainwater runs off fast, hot, and dirty. It moves fast and hot because it’s traveling over warm concrete and asphalt, through culverts and channelized streams. It’s dirty because of what it picks up along the way. When it hits creeks, rivers, or the bay, the runoff can be deadly to the plants and animals it touches. Motor oil interferes with the development of fish eggs and embryos, says Ben Greenfield, a researcher at SFEI. And even biodegradable detergents are harmful to a wide variety of marine animals. Phosphates or no, detergents break down the protective external mucus layers of fish, leaving them susceptible to infection by bacteria and parasites. Detergents can also damage gills, inhibiting respiration. The breakdown of surface tension caused by detergents also increases the amount of chemicals fish and other marine organisms can absorb, making them more vulnerable to the cumulative effects of other harmful pollutants. On the other hand, washing a car at a professional car wash is environmentally friendly. It diverts the toxic grime into the sewage treatment system, where it is processed like the toxic waste it is. Actually, more and more car washes pre-treat their waste water too, filtering or settling out the gunk before reusing the water and then, finally, sending it on to sewage treatment, says Patrick Shea, president of the Western Car Wash Association. Over 85 percent of California’s car washes recycle their water now, he says, and that percentage is growing as water prices rise and droughts become more common. So professionally washing the road grit off a car before it rains makes sense. If everyone did it, we could recapture tons of the deadly gunk cars put into the environment in the first place. Unfortunately, drivers are less likely to wash their cars when it looks like rain, assuming that rain will take care of the mess for them and that the waxy shine that says to the world “I am a clean person to whom nothing harmful sticks,” will be enhanced by the rain anyway. Here in the Bay Area, however, nary a raindrop may fall for eight straight months. From a purely environmental point of view, it may do more harm than good to wash a car during the dry season, just when people tend to bathe their cars the most. Even a professional car wash with excellent water recovery and recycling equipment uses about 20 precious gallons of water per car. Less green car washes can use up to 60 gallons. The average car owner washes her or his car four times a year, but many people wash their cars ten times that often. Half of car washers use professionals, and half do it the destructive way, by themselves in the street or driveway. (Incidentally, if you must wash your own car, do it on a lawn, where the runoff will be filtered by the ground and where the phosphates can fertilize the grass.) During the long dry season, think of your car as a toxic magnet attracting environmental contaminants as it drives. If flattened, California’s 25 million cars and trucks would cover a surface area exceeding 19,000 square miles. That’s one big air filter. The dirtier the car, the more contaminants it’s temporarily locking up. I don’t know at what point a car’s exterior becomes saturated with grime, but according to my unscientific experiments, it seems to occur between the second and third weeks of the third month. I also have a bright idea for increasing the car’s capacity as a toxic storage site, while also fulfilling its traditional psycho-social function. Perhaps that strange urge to rub Turtle Wax into a car each summer could be redirected instead to the application of a thin layer of something slightly tacky, say olive oil or petroleum jelly. You could multiply your car’s toxic holding capacity by at least five times that way. A more serious solution has been proposed by the Oakland-based non-profit Save the Bay. Along with the Bay Area Open Space Council, the organization is sponsoring new legislation that addresses the NPS problem from another direction. The bill (AB 204) would exact a six-dollar fee on each car registered in the nine Bay Area counties (each of which could choose whether or not to participate in the program). This would generate funds to “reduce, remediate, or otherwise mitigate for the adverse impacts of motor vehicles and related facilities on the quality of the surface waters of the San Francisco Bay Area.” In other words, when a Bay Area resident registered a car he or she would help pay in advance for removing some of the poison that the car would contribute to the bay over its lifetime. If all nine counties participated, the fund would generate about $30 million a year, which would be used by the counties themselves and the State Coastal Conservancy to fund “natural resource projects” such as wetland restoration. These restored habitats would help slow, cool, and clean NPS. The bill is expected to make its way toward the Governor’s office later this year. Of course, if I got rid of my car altogether, and chose to walk or ride a bike, I’d neither have to pay the new registration fee nor worry about how and when to wash the car. And I’m sure at least one of my neighbors would still be willing to let me help rub Vaseline on his car each spring. Gordy Slack is a freelance science writer and a contributing editor for California Wild. |
