For those of you who read the newspaper over breakfast, a fair warning: Today’s topic is not for those with queasy stomachs.

I’m afraid it’s time to talk about … poop.

The topic came to mind as I was reading a Janet Evanovich book in which Stephanie Plum’s dog, Bob, heard nature call while he sat in her car in a fast-food parking lot. She let him out to take care of business, and he did: right in the middle of the lot.

I don’t need to go into details. But while while the description made for humorous reading, the method made me realize that some pet owners – of both dogs and cats – in our community don’t do much better under similar circumstances.

In her Nov. 13, 2007, article, “The environmental impact of pets,” San Francisco Chronicle columnist Christie Keith noted that “America’s 73 million dogs produce around 10 million tons of dog poop per year … (and) the litter from America’s 90 million pet cats results in around 2 millions tons of cat litter being sent to landfills each year.”

That’s a lot of waste, the idea that it’s all natural is not quite true.

Fecal matter does biodegrade after a while. It’s never quick enough, though, for those of us who aren’t as regular as we should be about picking it up, or for other people who find the unwelcome droppings left in their yards by inconsiderate dog-walkers who don’t clean up after their pets, or by felines left to roam free to make deposits in neighbors’ vegetable gardens and flower beds.

However, it’s really more than a problem of just being unsightly, or smelling bad or being disgusting to step in.

On a minor level, dog poop contains nitrogen that feeds weeds when it’s left on lawns.

But worse, both dogs and cats harbor some nasty types of bacteria in their guts that are released when they do what they have to do. These include E. coli, fecal coliform bacteria, giardia and salmonella. Cats can contribute Toxoplasma gondii. Both can contain parasite eggs that can be passed on to other animals or to humans.

These bacteria, left on lawns, in gardens or in parks, are washed away by rainwater into storm drains and then move on to rivers and stream, polluting the water for humans and wildlife. In many areas, the problem is bad enough to close beaches and require posted warnings about exposure to the water.

Unfortunately, the bacteria means that poop can’t be composted for use on vegetable gardens.

For dog owners who like to walk their dogs in public areas, the best plan (and one that is, in fact, the law in Lawrence) is to always carry a bag with you, always pick up your pet’s deposits and always toss them in a garbage can. The plastic bags your newspaper comes wrapped in works for smaller dogs, and plastic grocery bags can work for larger ones, but this creates another problem of the waste being encased in a nonbiodegradable container that will stay in the landfills for hundreds or thousands of years. Some companies make biodegradable bags, but these can be prohibitively expensive for many of us.

Dog poop can be safely flushed down a toilet – our city waste management systems can effectively deal with that – but if you’re like me, the very thought of doing that makes me gag.

Cat poop in a toilet, however, is not recommended because our waste management systems aren’t designed to handle toxoplasma. It seems that, for now, we’re still best off to empty our litter boxes into bags and throw them in the trash.

Regardless of how we handle the waste, the Lawrence Humane Society asks all pet owners to be responsible for the droppings our pets leave. It’s the right and legal thing to do.