Herbicides Absorbed by Dogs

“It is ironic to think that man might determine his own future by something so seemingly trivial as the choice of an insect spray.” – Rachel Carson, Silent Spring Cover- Journal of Total Environment - herbicides

Now that summer is around the corner, many people will take to working on their gardens and grass lawns in the quest to achieve and  maintain the perfect green lawn. But monocultures are anathema to nature and people often turn to herbicides to produce that perfect lawn.

The two largest Canadian provinces, Ontario and Quebec, have had a ban on cosmetic herbicides for a few years. Other Canadian cities and towns are have not waited for provincial legislation and have implemented their own municipal bans. As far as I can tell no such legislation exists anywhere in the USA.

Chronic exposure to herbicides has been implicated in the increased risk cancer and neuropathologies; in dogs it has been connected with increased risk of risk of bladder cancer. This is of particular importance to some breeds; Scottish Terriers, Shetland Sheepdogs, Beagles, West Highland White Terriers, and Wire Hair Fox Terriers all already have elevated  risk of bladder cancer. (PDF)

A study published in the Science of the Total Environment has some disturbing findings about commonly used lawn herbicides.

The first experiment tracked pesticide residue under different grass conditions – green, dry brown, wet, and recently mowed grass. Herbicides were present even 48 hours after application and longer under brown conditions. Chemicals were also detected in untreated lawns which suggested chemical drift from nearby sources. So if your neighbor sprays then it’s probably getting on your lawn too and it is there for a good 2 days.

The second part of this paper looked at concentration of 2,4-D, MCPP, and dithiopyr in dog’s urine. The study found herbicide in the urine and 19 of 25 dogs from households with treated lawns and 4/8 dogs from untreated households. And the last bit of bad news is that contaminated dogs may be acting as vectors and exposing their owners to these herbicides.

Those that still spray lawn chemicals should keep in mind that these herbicides don’t just stay on the grass, they are making their way into animals exposed to that grass too – that includes dogs, wildlife and children.


Mechanical herbicide


Knapp DW, Peer WA, Conteh A, Diggs AR, Cooper BR, Glickman NW, Bonney PL, Stewart JC, Glickman LT, & Murphy AS (2013). Detection of herbicides in the urine of pet dogs following home lawn chemical application. The Science of the total environment, 456-457C, 34-41 PMID: 23584031


8 thoughts on “Herbicides Absorbed by Dogs

  1. I have known for a long time the implications of herbicides on pets and kids, and you would think there would be more concern by homeowners. This is a very important post and should be shared to many. I will add your link in my next post to all gardeners.

    • Some striking findings was the length of time it can continue to show up on the grass – up to 3 days on dry grass; the level of unintended contamination to other plots and of course the chemicals being absorbed into the dog’s system.

      I didn’t go into it – not being a gardener – but I’m sure you have other less/non toxic suggestions.

      • The best non toxic solution is letting nature take care of itself. The insects do their job and native plants do their part. But homeowners are far too concerned on having the perfect green carpet of lawn and lawn companies make a fortune on this. Homeowners also plant the wrong plants for where they live, stressing out the plants, requiring more and more chemicals. I am a designer so I have to contend with what people want, not always what they should be planting. Also, it is VERY difficult to convince them to try more a natural approach. Keeping a lawn healthy does not have to include chemicals, but, like you showed, it may require hard work.

  2. Hello,

    Just wanted to drop by and say that I linked to this post in my own post today about lawn chemicals–it was recommended to me by Zemanta for a related article as I was writing. (Your post appears in the “Related Articles” section at the bottom of this post:

    Great findings and research. Thanks for spreading the word on the dangers of these chemicals.


  3. Pet peeve: use of the term “herbicide”, which is a broad term for a large number of unrelated chemicals with wide range of mode-of-actions, toxicities, environmental persistence, and use patterns, as if it were a specific term. That paper about bladder cancer in Scottish Terriers doesn’t even say which “herbicides” are implicated. Even digging through the original study finds that the researchers only looked at one type of herbicide, but use the specific name of the chemical (2,4-d) and the term “law chemicals” interchangeably. Sloppy and misleading. Acetic acid is also an EPA regulated lawn herbicide.

    Canada’s ban on “lawn herbicides” was a premature and reactionary response to the public’s fear, not based on science. (Similar to the EU’s ban on neonicitinoids).

    I certainly agree that we over-use pesticides and herbicides in the US for cosmetic reasons, and I’m all for banning or restricting the use of SPECIFIC chemicals in SPECIFIC circumstances where warranted. But PLEASE can we be more specific when we talk about the risk of “chemicals” in our lives? Otherwise we sound as foolish as those who eagerly agree to ban dihydrogen monoxide once they learn how dangerous it is.

    • I agree with the un-specificity of ‘herbicides’ and ‘lawn-chemmicals’ but I made sure to mention the specific chemicals involved (2,4-D, MCPP, and dithiopyr); it’s an editorial choice made for the sake of flow.

      I don’t consider the various provincial bans premature as there was already good evidence to make the case limiting the use of 2,4-D; it’s more of a discussion of risk and comfort than actual scientific evidence, specially when someone else’s actions are putting you at risk.

      I wrote “This is of particular importance to some breeds; Scottish Terriers, Shetland Sheepdogs, Beagles, West Highland White Terriers, and Wire Hair Fox Terriers all already have elevated risk of bladder cancer.”. I don’t think that leaves the reader with the impression that they are getting cancer from this herbicide. Perhaps it may have been more clear as a single paragraph, though it’s also conveys the meaning I want as it stands. I hope the reader took that if their dog had an elevated risk then it’s not wise to expose them to more environmental insults.

      I will try to be more consistent with the terms.

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