(originally published in The Planet magazine)
Urban watersheds are a battered bunch. Raw sewage, pesticide- and fertilizer-laced farm runoff, stormwater drainage—all are contaminants that find insidious ways to reach watercourses, polluting surrounding watersheds and endangering their inhabitants. Whistle-blowers are quick to point fingers at the usual suspects: cars, commercial agriculture, population density and the like, but another culprit may lurk—or sit, or lie, or play fetch—in their very backyards.
Meet Spot, an unwitting accomplice to ecological degradation.
Everyone can relate to Canis familiaris, also known as the domestic dog: man’s best friend, the vigilant sentry, a loyal companion through thick and thin. Molded into myriad forms by centuries of selective breeding, dogs of all shapes and sizes have become one of America’s most popular pets—second only to cats—with 39 percent of U.S. households owning at least one, totaling 74.8 million pooches in all, according to the American Pet Products Manufacturers Association 2007-2008 National Pet Owners Survey.
Lots of dogs eat lots of food, and in turn make lots of poop. On average, a single dog produces three-quarters of a pound of waste per day, according to Kym Fedale, environmental educator with the City of Bellingham. Whatcom County is home to 37,000 dogs—about one for every five people—that cooperatively produce nearly 19 tons of dung daily.
To be sure, a lot of this poop is picked up and bagged by law-abiding citizens walking their pooches (Bellingham’s spotty scoopers face a $46 fine if caught in public). But what about those neglected nuggets on the trails? And what comes of the piles that owners leave in the privacy of their yards?
It ultimately goes into the water. Water that people recreate in; water that aquatic wildlife call home.
Odious enough as it is prima facie, dog feces harbor numerous pathogenic microorganisms to boot, including salmonella and E. coli, as well as the intestinal parasites hookworm and roundworm, Fedale said. Doggie doo also contains 107 fecal coliforms, or intestinal bacteria, per gram, roughly the same as human feces.
Dog poop is nasty stuff—no surprise there. But how do turds go from being perky lawn rosettes to water-borne waste?
Unattended poop does not simply vanish into the grass, as many pet owners would like to believe, Fedale said.
As rain souses Bellingham and drenches these droppings, resident bacteria spring to action and break down the organic compounds (most important of which are the nitrogen- and phosphorus-based compounds, used by plants as food), converting them into inorganic, more water-soluble forms.
The poop rapidly decomposes, weather permitting, and leaches its constituents—namely, the nutrients nitrogen and phosphorus, and various pathogens—into the surface water, where they will either flow into storm drains toward detention ponds or directly join nearby streams. (During this transition from solid to mostly-liquid poo, hookworms and other parasites, as well as some pathogenic microbes, percolate into the soil, where they can remain active for weeks—even months in some cases, as with giardia and salmonella—posing risks of disease to both humans and wildlife.)
In a detention pond, stormwater drainage slows to a crawl, allowing larger particles to settle out of the sluice, said Bill Reilly, storm and surface water manager for the City of Bellingham. This torpor gives pond vegetation a chance to snatch up some nitrogen and phosphorus, but that’s the extent of stormwater treatment for much of Bellingham. Any dog-waste pathogens, which are far too small to settle out, and unused nutrients are piped from the pond into streams and rivers.
Once the poop’s nutrients and pathogens enter watercourses, they join other non-point source pollutants—pollutants whose origins are myriad and diffuse—in a homogenized slurry that eventually drains into lakes or the sea. This runoff, which can contain unnaturally high levels of nitrogen and phosphorus, leads to nutrient-loading, or eutrophication, and can wreak long-term havoc on aquatic ecosystems.
In freshwater basins such as Lake Whatcom, phosphorus is a limiting nutrient, meaning that its presence (or absence) largely controls aquatic plant growth, said Leo Bodensteiner, assistant professor of environmental science at Western Washington University. If excess phosphorus is present in the summer months, i.e., when sunlight intensity and duration are peaking, photosynthetic phytoplankton capitalize on this surplus, multiplying exponentially until the nutrient is depleted. After exhausting their fuel, the phytoplankton die off in droves, their minute corpses sinking down to the cold, unlit depths of the lake. In this oxygen-poor abyss, bacteria set about metabolizing the billions of corpses, using up what scant oxygen is available and excreting phosphorus-laden wastes in return. The result is anoxia, or oxygen-stripped “dead zones”, often abundant in phosphorus, at the lowest, coldest depths—areas where large species of freshwater fish typically dwell in the summer.
With the arrival of winter comes inclement weather, roiling surface waters of the lake with windstorms and rainwater input. This mixing occurs throughout the lake’s depth-profile, churning up phosphorus-rich bottom layers and effectively refueling the eutrophic cycle.
Nutrient-loading can sound a death knell for lakes, creating an endless loop of algal blooms and die-offs that cloud the water in summer months and asphyxiate fish, Bodensteiner said.
“Once you get the ball rolling, you get this snowball effect,” he said, referring to the eutrophication of Basin 1, the shallowest and most populous of Lake Whatcom’s three basins. “The lake is a green soup in the summer with no oxygen in the lower layers, and it gets worse each year.”
The entire Lake Whatcom watershed is home to 3,598 licensed dogs, according to an August 2008 study by the Washington State University Whatcom County Extension, that produce as much poop as 1,000 humans every year. And if a 1999 survey is any indication—results found more than half of Lake Whatcom dog owners didn’t pick up piles in their yards—lots of this ca-ca still ends up in the lake.
So poo on the ground doesn’t stay put; in fact, it’s highly mobile (disregarding the mileage of trod-upon turds, that immeasurable distance) when the weather’s wet. And it’s hardly innocuous, so, naturally, every owner should be bagging the crap, right?
Fortunately, many here do: a 2008 survey by the City of Bellingham found, of those questioned, 75 percent of dog owners in the Whatcom Creek watershed pick up after their pets both in public and at home. Of those doing backyard doo-doo duty, 75 percent are also properly disposing of it, i.e., bagging turds as trash or flushing them down the toilet.
But despite sundry reasons to scoop—to wit, compliance with city law, ecological stewardship, avoiding the stigma of being a turd-abandoner—some still leave their pets’ leavings out in the rain.
Owners’ excuses are numerous, if nothing else, Fedale said. Some claim they don’t have time, others dislike the handling of poop (fancy that); owners of smaller breeds feel their pooch’s paltry contributions are insignificant in the scheme of things.
“The size of the dog doesn’t matter—the poop is composed of the same ingredients,” she said.
Some hold the misconceived notion that dog poop is a natural fertilizer, perfectly in harmony with their grassy yard or the woodland undergrowth near trails.
In reality, the sheer density of dogs in Bellingham—an average of 450 on each of the city’s 25 square miles—produces far more waste than a natural ecosystem can handle, Fedale said. Also, dog poop is rich in protein and phosphorus, a veritable nutrient overload; the mammals naturally found in an average square mile of undisturbed Bellingham forest (e.g., four fox, eight and a half skunks, zero-point-one lynx, and so on—a much smaller distribution of animals, basically) produce relatively nutrient-poor scat, and much less of it.
And one must remember that very little, if any, of Bellingham’s acreage qualifies as “undisturbed forest”; indeed, most of the city is covered by impermeable asphalt and concrete, two surfaces conducive to channeling toxic runoff toward watercourses.
So what to do about all this poo? Most cities have laws punishing negligent pet owners, to varying success: Bellingham’s pooper-scooper law (enacted in January 1987 and modeled, like similar ordinances across the country, after New York’s seminal 1978 Canine Waste Law) is largely flouted, said Laura Clark, community outreach director for the Whatcom County Humane Society.
“The law is difficult to enforce because a witness needs to be present,” she said. “Unless a citizen files a verifiable complaint, our officers need to be there when it happens, and they can only be in so many places at once.”
A recent innovation, used overseas in cities such as Vercelli, Italy, could be the smoking gun (or steaming pile) for scooper laws worldwide: doggie-DNA testing. By procuring the genetic fingerprint of every registered pooch within city limits, Vercelli officials hope to compile a DNA database, allowing police to test unscooped poo, identify the offending owner and mete out justice accordingly.
One problem: What about all the unregistered dogs, pooping wherever they please? A 2005 New York Times Magazine article by Stephen Dubner and Steven Levitt suggested that cities offer owners a cash incentive to license their dogs (instead of charging an annual fee, as is currently the norm), and in the licensing process collect and catalog Fido’s DNA.
Whether this system proves effective, or even financially feasible—Dubner and Levitt estimated that DNA tests for the million or so dogs in New York would cost around $30 million—has yet to be seen. For now, Fedale and the City of Bellingham are taking a more grassroots approach to combat crap.
The key is prevention via education, Fedale said. She heads the Hounds for Healthy Watersheds program, a volunteer-run operation that sends conscientious citizens to Bellingham’s trails and parks, armed with informative flyers, dog-poo bags and a penchant for shooting the shit.
“Our volunteers approach people with dogs and ask if they have a bag—if they don’t, we hand them some and give the spiel; if they do, we reward them with coupons for things like dog treats,” she said. “It’s the one-on-one contact that really makes the difference.”
Informing owners of the ecological consequences and health risks from dog waste is crucial, Fedale said; according to the Whatcom Creek survey, many of the regular scoopers weren’t clear why it was the right thing to do.
“Our job is to educate through public interaction,” she said. “We’re hoping to create a social norm where the majority of owners pick up after their dogs, and the community is shocked by those who don’t.”
The success of such programs depends on widespread citizen involvement—specifically, irresponsible owners need to clean up their act. With pooches comes poop, so unless these scoundrels want Bellingham’s watersheds going to the dogs, so to speak, they better start scooping.