Dog Waste is Harming the Environment. In Many, Many Ways…

Our gentle dog Ruby was diagnosed with malignant melanoma last year. She was diagnosed shortly after we rang in the supposedly post pandemic New Year with the resolution: “have more fun.”

Ruby was just five years old at the time of diagnosis. Malignant melanoma, we now know, is unbeatable in dogs. Within a mix of variables—how early the cancer was detected, where it has spread, success of tumor and surrounding tissue removal, and subsequent treatments—lies an estimate of our dog’s average expected remaining lifespan. Best case, apparently, is another couple of years with our sweetest family member.

After Ruby’s excised mouth tumor tested positive (the tumor was discovered by my daughter who just happened to see a strange black mass on Ruby’s gumline), Ruby’s regular veterinarian referred us to a list of recommended oncology groups for further surgery. The first available appointments were all many weeks out. Pandemic loneliness had brought about a surge in pet ownership and with that surge, overwhelming demand for veterinary appointments of all kinds.

Securing a timely surgical appointment turned out to be challenging. The cancer and the appointment delay, combined with the ominousness of the unknown of the rapidly spreading omicron variant put our “have more fun” resolution on indefinite hold. Eventually, the timing of a phone call to check in on appointment availability landed us a serendipitous appointment at the University of Minnesota Veterinary Medical Center.

Ruby after surgery.

Within weeks, Ruby was sedated for the removal of some lymph nodes and much of her upper left-side gum tissue. After spending the night at the surgery center, she came home frightened and in pain. She of course had no clue what had happened to her now-Frankensteined mouth and snout. Ruby was clearly shaken. The experience felt reminiscent of sci-fi Martians beaming up a human subject into a flying saucer to conduct “experiments” and said amnestic victim waking up the next morning in their own bed feeling greatly changed but unsure in what way. I think that’s how Ruby felt.

We took turns sleeping with our restless dog and rotated duty sitting with her throughout the day. We rubbed her back and her belly. We did our best to let her know how much she is loved. Slowly, she healed. Today she is much her old self. She has lung X-rays every three months and a vaccine of unknown efficacy every six months. Thank you to my sister who strongly recommended I buy pet insurance when Ruby was a puppy. I knew nothing about pet insurance. Without this coverage treatment options for Ruby would have been unaffordable.

Where Did the Cancer Come From?
Where did Ruby’s cancer come from? Her oncological surgeon offered no answers on the topic.

“We just don’t know.”

Dogs frequently get cancer, and some breeds more-so than others. And the variable-stew of what causes cancer makes parsing cause and effect challenging. Living in an environment (me, you and the dog) saturated in potentially cancer-causing chemicals, it feels expected that cancer can make a grand entrance at any time. Dogs come into contact with all kinds of chemicals in all kinds of ways. One way is through lawn treatments—the ones that come with the miniature sign that warns kids and pets to stay off the turf, as well as the treatments homeowners apply themselves. Research indicates that some lawn chemicals are not innocuous. Canine bladder cancer and canine malignant lymphoma are among possible lawn-treatment-related cancers.

My father, circa 1934, with pet puppy before lawn chemicals and monthly pet medications became the norm. Processed dog food would have likely been beyond my family’s means.

Other ways dogs come into contact with chemicals is through prophylactic oral and topical veterinary medications (parasiticides). Keeping our pets free of fleas, ticks, and heartworm is encouraged for animal health and well-being. But some insecticides found in pet meds, such as permethrin and fipronil, may have their possible downsides. Permethrin has been linked to lung cancer and liver tumors in dogs, and fipronil to thyroid cancer. (Although I find no research that validates these claims often cited on websites—mostly websites that tout alternative care for pets).

Excess Nutrients are Introduced to the Environment Via a Dog’s Poop or Pee
Before Ruby’s cancer, I wondered about pet medications. Not about how they may negatively impact her health (never crossed my mind), but what they do to the environment when introduced via urine or feces. With nearly 90 million dogs in the U.S. (and perhaps a half billion worldwide), a lot of pet waste—an average of .75 pounds per dog each day—has the potential of making its way into the environment. Do the math. It’s a big number.

Pet waste is quite different from wildlife waste. According to the website of the non-profit organization, Leave No Trace, “Wild animals are consuming resources and nutrients from the ecosystem, and then promptly returning those same resources and nutrients. Essentially, the system is a closed loop with no net gain or loss in nutrients or resources. When we start adding in nutrients from pet waste, the ecosystem balance is thrown out of equilibrium. Our dogs likely aren’t eating Oregon-grapes, Chokecherry, or other native plants from the ecosystems they leave their waste in, but instead eating nutrient heavy pet-foods designed to give them a complete and healthy diet. Unfortunately, these same pet foods result in excess nutrients in our outdoor spaces if pet waste isn’t picked up.”

Dog Waste is a Listed Pollutant
Research confirms that dog urine, which contains nitrogen, and dog poop, which teems with phosphorus, cause environmental problems in soil and water. Pet waste was officially categorized as a listed nonpoint source pollutant by the Environmental Protection Agency over 30 years ago (it’s in the same category as an oil spill). We dump nitrogen and phosphorus onto our lawns to make them look AstroTurf green. What makes lawns green also makes ponds, rivers, wetlands, streams, and lakes green. Dog pee and poop that make it into a waterbody help ignite algal blooms, which in turn deplete oxygen for wildlife that live in waterbodies.

Dog waste can also include salmonella, fecal coliform bacteria (an indicator organism), parasites such as hook worm and round worm, and more. It’s not “fertilizer,” and it’s not “natural,” as many people try to convince themselves when they choose not to pick up dog waste. And the low pH and high acidity of dog waste are not beneficial for the garden or lawn.

So, dog waste (that’s both pee and poop) in and of itself is considered a pollutant. But dog waste that’s full of prophylactic parasiticides takes its toxicity to an even higher level.

Dog Waste as Pesticide
A problematic impact of the largescale use of prophylactic parasiticides is the question of what happens when pet feces and urine, or skin treated with topical veterinary medications, come in contact with…insects? Monthly dog medications contain insecticides and acaricides.1 So then, does a dog’s waste. My dog’s monthly oral medications contain the pesticides afoxolaner and ivermectin and pyrantel. My dog’s waste is a pesticide of sorts.

Recall that about a half billion dogs worldwide contribute around .75 pounds of excrement each day to the environment. Some of these dogs around the globe are not prophylactically medicated. But let’s assume many, if not most, are. Insecticides are non-target. Non-target means these insecticides don’t know the difference between a hookworm, a tick, a bumblebee, or a butterfly.

I emailed Dave Goulson, bee ecologist, author, speaker, professor of biology at the University of Sussex, and the founder of the Bumblebee Conservation Trust, for some thoughts on the topic. He kindly responded, “We regularly and prophylactically treat our millions of dogs and cats with powerful poisons intended to kill internal worms and external ticks and fleas. While a desire to keep our pets healthy is understandable, we should also be aware that these chemicals end up in the environment, and just a few billionths of a gram is enough to kill bees, butterflies, or aquatic insects.”

That pet medications can impact aquatic insects2 initially puzzles me. But Goulson explains in his email, “Flea treatments are commonly dripped onto the necks of pets. In the UK, the active ingredients (fipronil and imidacloprid) have been found in every river sampled, the most likely source being dogs swimming in rivers and product being washed off their bedding.3 The dose applied to a single dog every month is enough to kill 60 million honeybees.” According to an article in the Guardian, (“Pet flea treatments poisoning rivers across England, scientists find”), “Fipronil is one of the most commonly used flea products and recent studies have shown it degrades to compounds that are more toxic to most insects than fipronil itself.”

Research on the Ecotoxicity of Prophylactic Pet Medications is Scarce
Despite the outsized usage of prophylactic pet parasiticides, the ecotoxicity of the wide array of available pet medications in all their forms—oral, topical drops, shampoos, collars, and more—is mostly unresearched. The potential risk of each available product (both individual ingredients and formulations) to vertebrates, species of invertebrates, the amount of the insecticide that is or is not metabolized by the body, impacts on soil fauna and vegetation, persistence, and more, has, for the most part, not been well researched.

As cited in an August 29, 2021 research thesis (“A rapid evidence assessment of the potential risk to the environment presented by active ingredients in the UK’s most commonly sold companion animal parasiticides”):

“. . . there is currently insufficient evidence to understand the environmental risk posed by these veterinary treatments and further studies are urgently needed to quantify the levels and characterise the routes of environmental exposure, as well as identifying any resulting environmental harm.”

The report continues, “The benefit of treating individual animals with suspected parasite infestations can be reasonably expected to outweigh the environmental harm caused by a singular dose of parasiticide. The benefit of prophylactically treating an entire population of healthy animals, however, cannot necessarily be expected to outweigh the environmental harm caused by millions of doses of parasiticides.”

While I’m hopeful robust research on the ecotoxicity of pet waste that contains parasiticides is forthcoming, I’m not holding my breath. As we know from history, eliminating suspect products and services that make people money is Silent Spring hard. And these products and services will only cease to be available after research offers indisputable evidence. By this time, the environmental damage will be well under way.

Things You Can Do. Choices You Can Make.

Working to Keep Ruby’s Waste Out of the Environment
Because I know Ruby’s waste is problematic in many ways, I promptly pick up her feces whether it’s in my yard, a park, a woodland, or the wilderness. I put her bagged waste in landfill trash (pet waste is never meant for home or municipal compost).

While Ruby loves roaming the yard, she’s not allowed in intentional habitat areas.

Ruby’s pee is harder to contain. She tends to relieve herself in the same general area in my yard, which I guess is better than peeing everywhere. I keep her out of intentional habitat areas in my yard and try to keep her on pathways or small grassy areas of the yard. When I work in my gardens, Ruby stays in the house.

While Ruby loves roaming the yard, she’s not allowed in intentional habitat areas.

Knowing how environmentally damaging the cumulative impact of pet waste can be in so many ways, I don’t let Ruby run loose in too many places. Like any dog, she loves running free in the outdoors, but the impact on wildlife from her waste and physical disruption keeps her on leash most the time. On the rare occasion she gets to run free in a more natural setting she must stay on the road or path.

Ruby’s favorite treat is to swim in a local lake during the warm months of the year. We try to minimize her impact on aquatic organisms by never using topical (including a collar) tick and flea products. While not foolproof (she can still release pesticides into the water via urine), it is nonetheless the better option.

I use a lot of signage in my yard. And in other gardens in the community that I steward. Cute signs like this one snag people’s attention. Don’t undervalue the power of signage to influence behavior.

As an aside, seeing dog waste in parks, public gardens, and woodlands is so discouraging. I think smart signage in public spaces that doesn’t engage in typical government-speak could be effective in educating and motivating. I still remember a sign at a neighbor’s swimming pool where I would often swim as a kid: “We don’t swim in your toilet. Please don’t pee in our pool.” Memorable. Humorous. And effective. I never would have dared to pee in that swimming pool!

I use a lot of signage in my yard. And in other gardens in the community that I steward. Cute signs like this one snag people’s attention. Don’t undervalue the power of signage to influence behavior.

Working to Keep Potentially Harmful Chemicals Away from Ruby
Within my control are my personal lawncare practices. I haven’t used fertilizers or herbicides on my lawn in decades. Ruby can at least roam the yard and chew on sedges in relative safety. (BTW, the lawn is doing swell, thank you). I have no control over my neighbors’ weed and feed practices, and little influence on what goes on in local parks and schoolyards. No Mow May has recently made headlines. And while No Mow May isn’t really a homerun for pollinators, it does keep participating homeowners and public works staff from pouring chemicals on turf for a short period of time. Perhaps the concept may more widely shed light on the environmental hazard posed by traditional American lawncare.

With trepidation and much guilt I continue to give Ruby her monthly prophylactic medications and feed her processed dog food. Other than trying to be a good steward of her waste, not using topical meds, and keeping her out of places she should not be, I am still part of the problem (not Ruby). I have homework to do in 2023. I need to change some of my behaviors. Starting with taking a cookbook for dogs out of the library and learning about flea and tick treatments that balance the health and well-being of Ruby with the health and well-being of other wildlife.

Loving All Animals as Much as We Love Our Pets
The canine/Homo sapiens connection is surely buried within our respective DNAs—a coexistence that dates back some 30,000 years. Our pets capture our outsized devotion. Think about the holiday cards you received this year. How many included the family pet in the family photo? (Guilty.)

For anyone who loves or has loved a pet, you know how deep the love for an animal can run.

If our love for our orangutan, dolphin, dung beetle, sweat bee, wasp, elephant, octopus, soil microbe, pangolin, rhino, wolf, or bat kin was as passionate, I think many of our ecological problems would be resolved.

For anyone who loves or has loved a pet, you know how deep the love for an animal can run.

1Without delving into a discussion of the classification of chemical groups and their impacts on animal species, it is noted that veterinary paraciticides contain both insecticides and acaricides. While acaricides contain chemicals that work to destroy ticks and fleas, according to biopharmaceutical manufacturer, Merck, “Insecticides are any substance or a mixture of substances intended to prevent, destroy, repel, or mitigate insects. Similarly, acaricides are substances that can destroy mites. A chemical can exert both insecticidal and acaricidal effects.”

2Pet meds show up in an array of environments. In one study, dog hair “retrieved from a bird’s nest contained fipronil, fluralaner and imidacloprid, indicating a potential pathway for the exposure of juvenile birds.”

3Not all pharmaceuticals are successfully removed by most wastewater treatment plants, thus, parasiticides from laundered pet bedding may reach waterbodies through discharge from water treatment facilities.

Dogs managed to survive on campfire castoffs and later, table scraps, for the approximately 30,000 years they’ve been hanging out with Homo sapiens. Then, everything changed.

A Food For Thought Afterthought
Dogs managed to survive on campfire castoffs and later, table scraps, for the approximately 30,000 years they’ve been hanging out with Homo sapiens. Then, everything changed.

Ever wonder what the dogs are talking about in these ubiquitous Dogs Playing
paintings? They’re grousing about the great international dog food conspiracy. A horrible turn of events for dogs (so dogs say) in which former electrician James Spratt, circa 1896, began marketing packaged dog food, forever condemning canine pets to suffer the eternal misery of processed food. Things only got worse when Ken-L Ration dog food hit the shelves in the 1920s. Today, we are instructed not to feed dogs human food; we’re told it’s not good for them. And giving them the “good stuff” turns them into beggars, whiners, and picky eaters. Give your dog a choice between a piece of cheese, a noodle, a slice of salami, crust of bread, licking the plate, a crumb so small you can hardly see it…or dog food. I know what will always land in last place.

“A Waterloo” by Cassius Marcellus Coolidge, the New York Public Library‘s Digital Library.