One of the advantages of going to scientific conferences or sitting in research meetings is that I get a view into the future …

Please pop over to the Substack version for a chance to comment (I would really like to hear your thoughts on this one!!)

But one of the disadvantages of this situation is that I hear stuff that I am not allowed to share - because the researcher needs to have the work peer-reviewed before appearing in an authoritative journal.

At the beginning of the year I was at one of those meetings, listening to a young researcher called Emily Thrift share her work. It was not yet published - but felt really interesting. She was asking whether we were inadvertently feeding the hedgehogs in our gardens food containing microplastics.

Microplastic contamination of human food has been investigated, and found at worrying levels. For some of the history of this research I recommend you look here.

I am sure you are aware of the rapid growth in plastic production - Emily writes that it has risen from 2 million tonnes in the 1950s to over 400 million tonnes in 2022. Are we living in the ‘Plasticene’?

You will have seen the vast amount of plastic waste - carelessly strewn across our shared environment. From the disgusting streams of litter alongside the road network to the ‘witches knickers’ tangled in farmland trees where silage wrapping has been blown into the wild - it is everywhere.

But these visible bits are not what we are worrying about here - it is what happens as they breakdown into tiny, and eventually, microscopic, pieces. It has been estimated that between 10-40 million tonnes of microplastics are introduced to the land every year, and up to ten times as much into the waterways.

When eaten, drunk, or inhaled, these particles have been shown to ‘disrupt vital physiological processes such as organ function and fertility.’

‘Although research has begun to show the presence of MPs (microplastics) in the bodies of humans, wild terrestrial animals, and pets, there is relatively little research on the dietary sources of these MPs or on the transmission of these MPs through ecosystems.’

This is the key question here - how is this stuff getting into us, into our pets, and into wild animals?

Most attention has been focused on human food, but what Emily did was to analyse pet food. Not only is pet food routinely given to hedgehogs, both in care and in our gardens, but also the pet food eaten by cats and dogs is distributed far and wide thanks to them pooping.

The paper has all the details, and there is no point me clogging things up here with them, so I will jump to the conclusions!

Emily assessed 38 pet and hedgehog food products - taking 228 samples in total. Microplastics were found in 63 samples. Of the 38 products, 76% were found to contain microplastic contamination.

It should be noted that just 1g of food was analysed per can, tray, sachet, or bag. So there is a large chance that the reality is worse than the evidence she presents. But her job was to make the task achievable and also replicable. The most common polymers she found were polyester, polyacrylamide, polyethylene, and polypropylene.

Her paper does not mention brands by name, but does reach a conclusion about the worst performing foods. Wet foods present the greatest exposure risk. Based on the mean microplastic content across all samples, a large dog fed wet foods is likely to ingest 313 microplastics per day.

That does not exonerate dry food though!

She also found that the worst culprits were from the cheaper brands.

How are these contaminants getting into our food in the first place? Well, there is the litter, over time, breaking down. But there are other pathways too - and a major one, not talked about much in her paper, comes from sewage sludge which is spread on fields as a cheap fertiliser, and this contains the microfibres that come from our clothes as they are washed - and so much else! These are now being found in the very invertebrates that hedgehogs love to eat. So not satisfied with simply removing these bugs and beasties from the hedgehog menus, we are contaminating what remains.

Then there is the poop …there are roughly 10 million each of pet dogs and pet cats. These generate nearly 600,000 tonnes of dog faeces and nearly 140,000 tonnes of cat faeces each year. And as I am sure you are aware - not all of this is collected and binned. Especially those free-roaming feline marauders.

Cats and dogs that are being fed on contaminated food are going to return those microplastics to the wild.

What does this all mean for how we feed our hedgehogs?

In her conclusion, Emily writes, ‘due to repeated daily consumption, pet foods are likely to represent a chronic exposure pathway for MP ingestion in both pets and wild mammals.’

And we also know that their wild food is also being contaminated.

We don’t know what impact this has on us humans, yet; let alone what it is doing to our pets and the wildlife we are trying to help. But I am heartened that this research is being undertaken so that we can’t claim to have not know what was going on should great problems arise. If there had been research going on like this at the advent of the agrochemicals that have so devastated our farmed landscape, I wonder whether we might have averted some of the worst of it all?

As for any recommendations? At the moment I imagine the biggest problem for hedgehogs is the loss of natural food. Supplementing that with potentially contaminated kitten-kibble is, I believe, better than the alternative of letting them starve. But what a world, where we have to make such a choice.