Pet Waste: Not a Natural Part of the Ecosystem

There are hundreds of animals in the forest, and nobody seems worried how their waste products affect the environment, so why should you worry about pet waste?

According to the U.S. Humane Society, 40% of United States households have at least 1 dog. Assuming Duluth is average, there are at least 125 dogs per square mile in the city (based on 21,000 households). This is a much higher population density of large mammals than you would find in a natural forest. You would expect to find an average of 4 fox, 0.8 coyotes, 0.1 wolves, 2.6 raccoons, 0.1 lynx, 0.6 bobcats, 8.5 skunks and 0.2 bear per square mile in undisturbed areas.

High animal populations yield lots of waste for the ecosystem to decompose. In a natural forest, this waste would slowly be broken down by microorganisms and would then be filtered through the soil by rain and snowmelt.

In an urban setting, the natural system has been altered by increased runoff due to impervious surfaces (surfaces that do not allow water to infiltrate the soil including rooftops and asphalt or concrete roads, parking lots and sidewalks). Pet waste that isn't properly disposed of will often be flushed into streams and lakes before being completely broken down.

Contaminants in Pet Waste

Pet waste may contain pathogens such as bacteria, viruses and parasitic worms that can be transmitted to humans who are gardening in contaminated soils or who are recreating in infected waters.

Some specific diseases and parasites carried in pet waste are:

• Campylobacteriosis - a bacteria carried by some cats and dogs causing gastrointestinal illness (diarrhea) in humans
• Cryptosporidium - a protozoan parasite that can be carried by dogs, cats, mice, some farm animals, and many other mammals causing gastrointestinal illness in humans. Common symptoms include diarrhea, stomach cramps, nausea and dehydration.
• Toxocariasis - roundworms that may be transmitted from dogs to humans often without obvious symptoms; may cause vision loss, a rash, fever, or cough.
• Toxoplasmosis - protozoan parasite that may be transmitted from cats to humans that can cause birth defects such as mental retardation and blindness if a woman becomes infected during pregnancy; symptoms include headache, muscle aches, lymph node enlargement.
• All of these diseases are of particular concern if contracted by people with with depressed immune systems.

Home composting piles should not be used for disposing of risky materials such as cat litter and dog doo. Find out why.

Learn more about the bacteria found in Duluth Streams.

Pet waste also contains nutrients that help weeds and algae grow. Excess vegetation growth in aquatic environments is both unsightly and it uses up the oxygen that fish and other aquatic life need to live. Oxygen levels are also reduced as bacteria decomposes pet waste (a process requiring oxygen).

What Should Pet Owners Do?

Most of us don't have dogs willing to use the indoor facilities, so pet owners need to clean up for them.

Pet waste should be picked up and either be:

• flushed down the toilet (be sure to pick out rocks and sticks first),
• put in the trash or,
• buried in your own yard. If you want to bury pet waste, make sure it is in a hole at least 6 inches deep, away from vegetable gardens and water sources, and in permeable soil (not clay). Do not add it to compost piles.

The Duluth pet control ordinance

(from the legislative code section of the City of Duluth website)

Sec. 6-38. Animal litter.

(a) The owner of any animal or any person having the custody or control of any animal shall be responsible for cleaning up any feces of the animal and disposing of such feces in a sanitary manner;

(b) It is unlawful for any person owning, keeping or harboring an animal to cause said animal to be on property, public or private, not owned or possessed by such person without having in his/her immediate possession a device for the removal of feces and depository for the transfer of animal feces to a receptacle located on property owned or possessed by such person. A device may include a plastic or paper bag which is used to recover animal feces;

(c) It is unlawful for any person in control of, causing or permitting any animal to be on any property, public or private, not owned or possessed by such person to fail to remove feces left by such animal to a proper receptacle located on the property owned or possessed by such person;

(d) For the purposes of this Section, the term public property includes, without limitation, streets, sidewalks, boardwalks, trails, boulevards, playgrounds and parks;

(e) The provisions of this Section shall not apply to the ownership of use of any properly identified service animal which aids persons who are totally or partially blind or deaf or have physical or sensory disabilities, animals when used in police activities by the city, or tracking animals when used by or with the permission of the city. (Ord. No. 5849, § 12; Ord. No. 9025, 4-29-1991, § 3; replaced by Ord. No. 9420, 8-9-1999, § 1.)

Finally, keep your pets safe around water. Algae blooms can be toxic to pets and humans alike. Be sure to check water conditions when dogs are playing near lakes or slow-flowing streams. Learn more.