As a society, we are becoming more and more conscious about how our actions affect the environment. With farming practices and manufacturing processes already under scrutiny for their use of chemicals, there has been a shift of focus onto things closer to home too. The spotlight has swung onto anti-parasite products again recently; with some specific concerns about the impact that these can have on our wildlife populations. Vets have always advised regular treatment of pets to prevent ticks and flea infestations, but perhaps we should be taking another look at the best way of doing this.

The toxic effects

Evidence has shown increased levels of chemicals from popular over-the-counter tick and flea treatments appearing in our rivers. Studies have shown fipronil and imidacloprid concentrations are increasing downstream of waterworks. These two chemicals are likely to have entered our waterways because of treated pets being bathed at home. (With washed-off products ending up in our sewers), owners washing their hands after applying a product and possibly because of owners disposing of leftover products inappropriately.

As these chemicals are insecticidal, they could kill other insects as well as the ticks that they were intended for. This could have a devastating effect on wildlife, affecting insect populations such as mayfly and dragonfly larvae. This in turn will affect the fish, birds and animals that rely on those types of insects for food.

Possible ways forward

So, what can we do?

Tighter regulation

One proposal is to tighten the regulations on over-the-counter products to help ensure they are being used correctly. Requiring a prescription from a vet for example will mean that owners are using products appropriate to their situation and are given accurate directions for their use.

Changing the way we use the products

Another solution that is starting to emerge, is a change in the way that vets recommend products. Currently, we advise all year-round prophylactic treatment against parasites to prevent cats and dogs from catching them in the first place. However, when we look at ticks in particular, the risk factor for pets is not all equal. Active dogs that walk off the lead in the countryside, especially in long grass where livestock or deer graze, will be at a very high risk of being bitten by a tick. It makes sense for these animals to have regular preventative tick treatment. However, a sofa-loving elderly dog who goes for a walk around the block once a day is very unlikely to encounter any ticks.

So, while receiving all-year-round tick treatment is perfectly safe for the individual and will do your pet no harm, we need to start looking at the wider impact. There are now tools owners can use online to assess their pet’s parasite risk such as Parassess. Take a look to see what it advises for your dog and use this information to have a discussion with your vet.

If your pet is deemed at risk of catching ticks, then you must treat them. Alongside well-known illnesses like Lyme disease, the risk of more exotic tick-borne diseases in this country is increasing. This is due to a recent surge in imported animals from mainland Europe.

Product types

If it is decided that your pet would benefit from tick treatment, what products are available and which is best for the environment?

Spot-on products

These are probably the most used anti-parasite products. Many of these contain chemicals that are effective against fleas as well as ticks (such as fipronil). These products are usually easy to administer; by applying a small squeeze of liquid to the skin on the back of your pet’s neck. However, these products can also be easily washed off, especially if the dog swims or is bathed within 48 hours of application. Even after this time frame, dogs that swim very regularly can impact the effectiveness of the spot-on treatment; implying that the chemical may get diluted ending up in the water.


Tick collars are a popular and easy answer for many. Some collars can last for several months meaning, it is an easy solution for owners that struggle to remember a product that needs to be administered more regularly. Collars can act as a repellent as well as kill ticks that have already attached.

Some of these collars claim to be water-resistant which means in theory they can be left on when the dog is swimming or being bathed. This contradicts the advice in the instructions of one popular product, however. It states ‘This product should not enter water courses as it may be dangerous for fish and other aquatic organisms’. This would imply that there is a risk of chemicals getting into the water; so this type of product may not be the most environmentally friendly choice for dogs that like swimming.


Tick tablets are becoming more frequently used, with several different varieties available. These often cover other parasites too such as fleas or worms, depending on the product. Some tablets can even protect for up to 3 months too. As the active ingredients of these products reach your dog’s skin internally, rather than being applied on the surface, this means that the product won’t leach out into the water. The downside is that some pets are not very good at taking tablets, so owners can find collars and spot-ons easier.

It is worth mentioning that the datasheet for one of these tick tablets states that its active ingredient (Fluralaner) is passed in the faeces almost unchanged. More research is needed as to whether this is going to have a long-term impact on the environment too.

Out of the three types of tick treatment discussed it would appear that tablets are the most environmentally sound, as the chemicals are unlikely to find their way into water courses. However, research is ongoing.


Your vet is the best person to speak to about the best treatment regime for your pet. The focus is shifting onto a more patient-specific parasite plan now, which will help to limit any unnecessary treatments, thereby reducing the overall risk of chemicals getting into our rivers and streams. However, if your pet does require a tick treatment then ensure he receives it regularly. You can have a chat with your vet about the most environmentally sound one to suit your needs.

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