Spot on pet treatments for fleas and ticks are polluting our waterways with pesticides. So how does a spot on pet treatment applied in the home get into our rivers and ponds in the first place?
The ecotoxic products we’re buying
I’m embarrassed to say that as a pet owner (my dog Bonny is pictured above), I had no idea until BBC Springwatch shared the data, that spot on pet treatments for fleas and ticks are polluting our waterways with pesticides. Fipronil and Imidacloprid (a neonicotinoid) are the two main pesticides concerned, and alarmingly both are banned in agriculture over ten years ago due to their ecotoxicity. In spite of this, they remain the main ingredients in the most popular off the shelf spot on pet treatments for fleas and ticks such as Frontline Spot On©, Advantage©, Bob Martin Clear Plus© to name a few. The picture below sets out the routes from our pets to our waterways.
The extent of the contamination
OK, so we know how this happens, and we know that its widespread and we know that in many cases the levels of pesticides being found are above the chronic toxicity levels for aquatic life. But to what extent is this really a problem? After all, these products are authorised for use, assumed environmentally safe, and are for sale without prescription or professional advice. You can pick them up in your local supermarket with no advice nor adequate warnings. Well, take a look at this:
A recent study of ponds on Hampstead Heath found that in all the dog-swimming areas, average concentrations of Imidacloprid and Fipronil were found to be 309 ng/L (nanograms per litre) and 32 ng/L respectively – both of which were more than 20-times larger than recognised thresholds considered harmful to invertebrate wildlife.
To add to this, a survey conducted by Wild New Forest and the Freshwater Habitats Trust has warned of the potential impact of powerful insecticides used in popular flea treatments for dogs on New Forest waterbodies. Researchers found Imidacloprid at several sites. At one of these, Dibden Bottom, levels of Imidacloprid were found at nearly double the internationally agreed toxicity threshold for aquatic invertebrates.
Doesn’t sound environmentally safe to me!
What the vets and pet owners say
You might begin to wonder how on earth these pet products can be authorised for such widespread and ill-informed use. Given this, it’s perhaps not surprising that many highly-qualified veterinary professionals are questioning the process for determining environmental safety in the pet treatment authorisation process. Here’s what one vet had to say:
“Social chemicals, including parasiticides, pesticides and herbicides continue to receive marketing authorisation based on out of date science. The negative consequences for human health, pet health and the environment may not become apparent for decades. 21st century evidence based test methods continue to be ignored, while out of date science is kept alive by government and industry to protect short term profits. A paradigm shift is sorely needed if we wish to promote life and health on the planet.”
Andre Menache, BSc(Hons) BVSc Dip ECAWBM (AWSEL) MRCVS Director Progressive Veterinary Association
Now if, like me, you love your pet and you love nature, this is worrying. Although the dosage for one application to one cat or dog only contains a small amount of pesticide, it all adds up. There are millions of pets receiving millions of small doses every month, so that’s one heck of a lot of pesticide. As I said at the beginning, I only found out about this by chance because I watch programmes like BBC Springwatch.
So, what about other pet owners? Well, this is what the research has found. Most dog owners were unaware of the environmental risks, and most would choose a safer alternative. I haven’t got a cat but from speaking with cat owners it would seem a similar picture.
Of course, this general not knowing is not surprising given the complete lack of warnings about dangers to aquatic life on product displays and packaging. You have to dive very deep into the small print to find even the slightest hint of risks to the environment. Couple this with the ease of purchase, inadequate precautions about dogs swimming and the lack of professional advice, you can understand why this is not at the forefront of most pet owners’ minds. On top of this our government, DEFRA, have known about this since as early as 2018 and still have not taken action.
In October 2023, over twenty NGOs’, including Wildlife Trusts, RSPB, Rivers Trusts and Angling Trusts to name a few, signed an open letter to government calling for action. In this letter they pointed out that and I quote:
“A single dose on a large dog of the neonicotinoid imidacloprid – commonly found in tick and flea treatments – is enough to kill millions of honeybees”.
More recently, based on responses to my letters to DEFRA and questions asked in parliament, it would seem there are at last signs of movement. As an example here is a quote from the reply to my most recent letter to DEFRA, in which they said:
“The first priority will be to raise awareness and improve pet owner education on risks and appropriate use”.
Now as pet owners we can all do our bit to help with this, and we can be guided by the science to help us to take the best course. Many vets are now questioning the current approach.
“Parasite treatment has become a central theme in pet healthcare, often as part of monthly subscription schemes widely promoted by vet practices. No one wants their pets to have parasites, right? The problem is that there is precious little data confirming that all these treatments are medically necessary in clinically normal healthy animals: in reality parasite incidence is relatively low, and ill health due to parasites even less common. Knowing what we do about environmental contamination with the medicines used, it’s time to reconsider our approach to parasite treatment.” Dr Andrew Prentis BVSc MRCVS Visiting Fellow, Grantham Institute, Imperial College London
