Kitty litter: A green conundrum

Dogs may be man's best friend, but statistically, more kitties roam American homes. The Humane Society and the American Veterinary Medical Association estimate that the U.S. has 10 to 15 million more cats than dogs as pets (about 90 million felines total, as of 2007).

So we buy heck of a lot of kitty litter, which piles up in a stinky mess in our landfills. Green Living Online says we dump about 2 million tons of cat litter each year into the garbage. The editors of E: the Environmental Magazine point out that common clay-based clumping cat litter isn't biodegradable.

Do we have a more eco-friendly option for our furry friends?

In the past few years, biodegradable litters have come out that are made from stuff like wood chips, corn, wheat, and even recycled newspaper. Greenies at TreeHugger and Ideal Bite recommend these kitty litters over the old-fashioned kind.

But I want to take a look at the benefits of these "natural" litters. Because I'm one cat-lover with a pair of finicky felines who go into a tizzy just if I rearrange the living room furniture -- so I'm not about to switch their litter before researching the heck out of the environmental claims!

First, some background. The clumping cat litters found in every supermarket and pet store have bentonite clay as the active ingredient. This naturally occurring substance clumps when wet and expands to several times its size. It has many industrial, pharmaceutical, steel foundry, and even wastewater purification uses. Bentonite is mined in the western U.S., particularly Wyoming.

Clumping clay litters earn two big complaints. Some websites suggest that because the clay swells up, if a cat ingests it, the clay could swell up inside and cause deadly blockages. Or the dust from the litter could cause respiratory problems.

About.com has an excellent summary of the "clumping clay controversy" and traces it back to a couple of anecdotal reports. No scientific studies have linked clumping clay litters to feline illness.

Another ingredient in common litters, silica, has also been hyped as a problem. The ASPCA notes that, at worst, pets may develop mild gastrointestinal upset if they ingest litter that contains silica. But litter usually passes through the digestive tract without harm. If you're really concerned, carefully observe your cat and then talk to your vet.

The other accusation against clay litter is how it's produced. Many green websites complain that bentonite clay is strip-mined. How bad is this process for the environment?

I think you have to weigh it against the alternatives. The fact is that every type of processing has a carbon footprint, and so far, nobody has done a detailed comparison. I've uncoverd some facts, and fellow cat fanciers can be their own judges.

The Wyoming Mining Association site has pretty detailed info. about the process used to extract this clay from the ground. This group mined 5.2 million tons of bentonite in 2005, and the deposits in Wyoming make up 70% of the world's known supply.

According to the site, before a mine is dug, the topsoil and vegetation are assessed and stockpiled for future reclamation. After mining, the area is reconstructed to become grazing land for ranchers. The association claims that the new area provides "four times more vegetative production than undisturbed land."

That's the traditional litter. Now let's look at some alternative brands...

• Cat Country Organic: Made from wheatgrass fiber.
• Feline Pine: Made from recycled pine wood.
• Good Mews: Made from recycled newspapers.
• Nature's Miracle: Made from corn cobs.
• One Earth Cat Litter: Made from corn cobs and yucca and pine woods.
• PaPurr Scoop: Made from recycled paper.
• Swheat Scoop: Made from non-food grade wheat.
• World's Best Cat Litter: Made from whole-kernel corn.
• Yesterday's News: Made from recycled newspapers.

Each of these materials has problems too. Farmed corn and wheat are often grown using pesticides that damage our water system. Non-organic corn may be of genetically modified stock. And the tree production for wood, then paper processing, involves plenty of chemicals and releases tons of greenhouse gases. None of these "natural" litters are truly clean either.

Also, most of these biodegradable kitty litters proclaim a big benefit is that they can be flushed down the toilet. I don't think this is a great idea. Thoughtful environmentalists know that water is a precious resource, and toilets aren't garbage cans. Let's save our valuable water for drinking, and put the cat poop elsewhere.

Another reason not to flush: sea otters. At least if you live in a coastal state and have a cat that goes outside at all.

Let me explain.

The Toxoplasma gondii parasite is found in many birds and rodents, and outdoor cats can acquire the bug from eating those critters. It usually doesn't do much harm to adult cats, but they'll pass the Toxoplasma eggs along in the cat's droppings.

It's the infected litter that's the problem. You may have heard that pregnant women shouldn't deal with the litter box -- this is why. If your cat is indoors-only (which is safest for the cat and other wildlife), you don't have to worry.

However, scientists from the UC Davis School of Veterinary Medicine found that 62% of dead sea otters found between 1997 and 2001 were infected with Toxoplasma. The suspected source was land-based runoff of the parasite. Landscape irrigation washes infected cat droppings from lawns into gutters, which drain into streams that feed in the ocean.

Municipal sewage systems can't always kill the Toxoplasma eggs because they have a very hard, durable coating. So when the treated sewage is released into the sea, that can hurt sea life as well. Let's not add to marine pollution with our kitty litter. A cleaner solution for those of us in coastal states is to keep the poop in the garbage.

As you can see, doing right by your cat and the planet doesn't come down to one simple choice. Do your own reading, weigh the pros and cons of the products, and decide how to clean up in a way that works for your feline family.