Monday, February 9, 2009

Water Quality and Dogs

I recently adopted a dog from an animal rescue group. Pet adoption has to be one of the nicest forms of “recycling” on earth. I love to walk along Sligo Creek in Silver Spring with her, even on bitter cold days. The woods are so lovely, the water so peaceful and we both enjoy taking in our favorite views (and smells) while we exercise.

But like a lot of dog lovers, I’ve often wondered how to handle the most indelicate issue of dog waste. Poop is not good for a creek, but wasn’t until I was “at the helm” of a leash once again that I really began to think and research the issue closely to figure out my approach to being a responsible dog owner and good watershed resident.

Cleaning up after a dog is not fun, and a lot of people only do it if they think someone is watching them. Maybe they figure that if the dog goes under some bushes, off the main path, that it is better to leave the droppings there because poop is natural and it will break down pretty quickly if we leave it out in the open air. They might think dog poop is no different from deer poop, or bird poop, or fox poop. (By the way, I think that might break some kind of record for use of the word poop in one sentence by someone who is over the age of five.)

It is kind of weird to bag up dog poop in some ways. You have to carry the stuff until you find a trash can. Some joggers and trail users will tie their dog poop bags to trees or bushes. My friend thinks that these people really mean to return later and do the right thing and take that poop to a can. They don’t like to run with the bag and they plan to get it on the way out, she claims. But I sometimes find those bags hanging from those same trees weeks later, like odd Christmas ornaments left by an extra mean Grinch.

And then you wonder if you do bag the stuff and throw it away… is it really better to have these plastic bags full of poop sitting around forever in our landfills?

Hunting around on the internet brings up some interesting research on the topic. Seems that landfills are not ideal, but almost everyone who has given water quality and soil sanitation any thought seems to agree that scooping poop is far superior to leaving it alone to decay.

For one thing, the intensity of dog ownership is astounding. In any watershed you can find millions of dogs. In fact, there are 74.8 million of them living in the US right now, according to the US Humane Society’s accounting.

But it only takes a small number of them to make an impact, because the bacteria levels in dog droppings can be very high. One gram of dog waste can contain as much as 23 million fecal coliform bacteria. Dog waste can also harbor Giardia, Cryptosporidium, Leptospira and Salmonella.

When you leave the feces along the creek -- or even on the sidewalk or lawn – storms can quickly carry those nasties to Sligo Creek, then the Anacostia River, and then onto the Chesapeake where they can pose serious health risks to both humans and wildlife. The EPA noted in some research conducted in the mid 1990s, for example, that if a twenty-square mile coastal bay watershed was home to only 100 dogs, two to three days worth of dog droppings would contribute enough bacteria and nutrients to temporary close that small bay to swimming and shellfishing.

Mike Smith has been testing the water quality of Sligo Creek as a volunteer with the Friends of Sligo Creek every other week since 2004. Most of his tests focus on things other than bacterial counts, such as temperature, ph, conductivity, nitrates, turbidity and dissolved oxygen. The Washington Suburban Sanitary Commission (WSSC) and the Anacostia Watershed Society (AWS) both do test regularly for bacteria, however, and Mike says their numbers show that dog waste is a big problem, and that generally around 15% of all the bacteria that is in the Sligo has been found to come from dogs.

“Bacteria is a major reason why a creek like Sligo doesn’t meet the Clean Water Act standards. Its supposed to be swimmable and fishable and bacterial contamination -- including dog waste -- is a big contributor,” Mike notes.

Besides bacteria, the release of excess nutrients from dog waste promotes algae and weed growth in watersheds, which can limit light and stop aquatic plants from growing. This can reduce the amount of oxygen, which fish and other aquatic animals need to survive.

Bagging poop for disposal in municipal landfills is not ideal. Plastic doesn’t break down over time and can accumulate quickly in dumps. You can help by using biodegradable bags, instead of those heinous newspaper bags we all wish didn’t pile up in the kitchen cabinet. If it really grosses you out you can even buy all kinds of contraptions which will make clean up easier and a bit more tidy.

Some owners also choose to use bagless scoops which completely contain the waste until it can be flushed in a toilet. I think this is really impractical and really gross. But hey, if you feel like doing it, go for it. Flushing will move the waste into municipal sewer systems where it can be handled just like human waste. (Homeowners with septic systems should avoid this method, since the systems can quickly become overwhelmed by the hair and ash often found in dog feces.)

Some municipalities also allow residents to bury pet waste, but this could also cause water pollution, and the amount of waste created by the average dog would make this quickly impractical in most Silver Spring and Takoma yards. Commercial digesters which are sold to break the waste down have not proven to be environmentally beneficial, and in many cases may not work any quicker than regular ground burial. (Queries about whether someone could bury waste in Montgomery County, MD did not turn up any specific laws or regulations. If anyone out there is aware of one that pertains, please let me know.)

Although it might be tempting to put dog waste into your compost bin, don’t ever do it. The fecal bacteria will not break down in the average backyard pile. Using compost that contains pet waste of any kind can pose serious health risks to people that visit your garden or eat your home grown veggies.

Its important to note, of course, that not all water quality problems come from dogs, and although dog owners can make a big difference by cleaning up after their pets, there are a lot of other ways we could improve the quality of our local creeks and streams.

(This story originally appeared in the February edition of the Takoma Park and Silver Spring Voice newspapers. As usual, all rights are reserved and you cannot use it without permission.)

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