There is, currently, a bit of a panic about poo. It’s not difficult to see why the news, which I myself have reported on, of the huge quantities of untreated sewage entering our waters has got the public in a sweat.

Whether it’s the sewage scandal in England, where there were 301,091 sewage spills in 2022, or Scotland where we only have a partial picture due to more limited monitoring, there’s a sense of faecal fury out there. People react instinctively, and with disgust, to anything that involves human excrement – particularly the idea that it might be floating around in our rivers and seas and that we might literally be swimming in it. 

But, for me, poo is not the central issue. Though I'm currently celebrating the awarding of bathing status to one of my local swimming spots, Wardie Bay, for me, faecal bacteria (which will now be monitored as a result) is not the biggest thing. Rather, poo is just the celebrity in a world of marine and freshwater pollutants, many of which worry me more. 

Before I go further, though, an acknowledgement. When journalists like myself criticise lack of monitoring of untreated sewage release in Scotland,  the response often given by Scottish Water and the Scottish Government, is that 66 per cent of our rivers, lochs and waterways are of good ecological status.

READ MORE: Scotland shockingly behind England in monitoring sewage releases

And they are right to do so. That’s clearly miles better than England, which can boast a mere 14 per cent of its freshwater bodies as meeting that status. It is, indeed, something to be celebrated.  

But, still, that figure leaves a third of our rivers, streams and lochs as poor or bad. It still leaves, according to the data published in 2021, 60 stretches of river in "poor" condition.

The cause of this ecological damage, is, of course, not just human poo. It's also agricultural run-off, other sources of pollution, the impact of invasive species and structural impacts we have had on our waterways.

A recent blog by the James Hutton Institute notes that “one of the biggest factors in the failure of fresh water to achieve a good ecological status is agriculture”. These impacts happen through chemicals such as fertilisers and pesticides, as well as manure and slurry from livestock.

“When they enter rivers,” says the blog, “they can cause eutrophication. This is when there are too many nutrients in the water causing an excess of algae, that can thrive on them, to the detriment of other life.”

What's clear is that, though we may measure faecal bacteria at our beaches and bathing waters, they are just the tip of the iceberg. Among the contaminants in our water to be concerned about are nitrates, phosphates, pharmaceuticals, antibiotics, microplastics, so-called "forever chemicals", endocrine-disrupting chemicals and pesticides.

READ MORE: Calls for Scotland to step up monitoring of forever chemicals timebomb

Microplastics arrive in our waters from numerous different sources that include contaminated sewage sludge spread on fields to untreated sewage discharges, the break-down of litter and the spillage of the small plastic pellets known as nurdles by industry.

The Clyde, according to a piece of research carried out by Greenpeace into microplastics in rivers around the UK, is contaminated with microplastics – though only at around a tenth the quantity found in the Thames.

Another study, by University of Bangor, found small amounts of microplastics in the Falls of Dochart and Loch Lomond, though at levels that are a tiny fraction, of, say, those found in Ullswater (which had around 10 times as many), the Thames (40 times as many) and the River Tame in Greater Manchester (at least 500 times as many).

We also know, through a Marine Scotland study that microplastics were present in the surface waters of all Scottish sea areas – and that the highest concentration was off the northwest coast of Skye, where surface water was estimated to contain 28,566 microplastics per square kilometre.

READ MORE: Sewage anger. The campaigners driven to test waters for themselves

Then there are the pharmaceuticals. A study published last year ranked the Clyde as the worst contaminated waterway, of those tested in the UK, for potentially toxic levels of pharmaceuticals. It was also the fifth worst out of 40 sites across Europe.

We mostly don't think about these things when we talk about sewage. We think about poo.

Yet I suspect it was partly plastics that reminded us of the ongoing presence of the sewage problem. The unmistakable presence of wet wipes and condoms and other flushed-away items washed up on the beach formed a kind of message. "What you flush away is able to make its way here." 

As someone who has written about sewage more than a few times, I know how the subject gets a big reaction – while other issues like the poverty of testing for forever chemicals in Scotland, or the issue of microplastics do not.

But just because it provokes doesn't mean it's the issue we should worry about most.

Sewage,  for me,  is just a wake-up call. I’m glad England’s water companies scandal is making us think about our waters – but there’s so much more to consider than poo.