But is it safe to swim? I should like to take you back to Kilwinning in 1854. As a medical student about to qualify, my great-grandfather James was called to help look after the victims of cholera in the ironworks there. Afterwards he received a letter from the Inspector of the Poor thanking him for his service. He must have been proud of this as he kept it and it is still in the family.
This occurred during one of several terrible epidemics of the disease in Glasgow in the 19th century, and it appears that the recruitment of students to help overwhelmed doctors during epidemics occurred then as it did during Covid-19. The cause of such epidemics was fiercely debated, but two years later the Yorkshire doctor, John Snow, working in London, was able to show it was likely transmitted by contaminated river water rather than by miasma in the air. At the same time and independently, William Budd in Bristol reported observations of his patients that led him to deduce the same method of transmission of another commonly fatal epidemic disease, typhoid fever. Faecal contamination of the supply of drinking water allowed transmission of what would be shown later to be two different bacteria.
Vested interests both among doctors with their theories and industrialists who ran the water companies allowed argument to persist until the work of Louis Pasteur and Robert Koch in the 1880s showed convincingly that germs caused disease, but the work of both Budd and Snow led to local measures of prevention and to the great Victorian public health movement.
Disinfection played a part, but the really significant effect on public health came from engineering of the supply, distribution and disposal of water, pioneered by the engineer Sir Joseph Bazalgette in London from 1852. The initial stimulus to this came from the desire of legislators to remove the stink of raw sewage which at the time was thought to be miasma transmitting these diseases, but the building of hundreds of miles of brick sewers, pumping stations and, by the end of the century, treatment plants led to elimination of water-borne cholera and typhoid in London and our other cities. This was inevitably paid for from public funds, at very great expense.
That was how it all started. My generation, and my father's and yours, have been fortunate to have lived through a period of relative freedom from such water-borne diseases. Relative, because I expect many of you will have suffered diarrhoea and vomiting after swimming in the sea at Mediterranean resorts or even off the coast of Britain. These are mostly caused by microbes, often viruses, that still find their way into the water of our rivers and sea, though happily our drinking water is always still safe in the UK. We can still fall ill, as I and several members of my family have, by eating ill-prepared shellfish or by swimming in local rivers, and now we all know why.
Sewage is still being discharged untreated into rivers and sea in the UK, including Scotland. Three things are largely responsible. First, the population has increased steadily, necessarily producing more waste. Second, climate change has caused more severe episodic downpours of rain and localised flooding. Third, we still largely rely on the same capacity for collection, treatment and drainage that our forebears built for us with their taxes. That system was built to eliminate sewage from our drinking water, originally discharging the sewage into the sea until purification plants were built. The flaw in the system is that the part of it responsible for disposal of household and industrial waste is also the part that removes excess rainwater, the latter diluting the former. With increasingly heavy rainfall and flooding from climate change, this part of the system is regularly overwhelmed and there is no choice other than to discharge the diluted but untreated sewage into the local river or sea.
In Scotland, control of this system is the responsibility of our government's Scottish Water, regulated by the Scottish Environmental Protection Agency (SEPA) and, in England and Wales, of the private companies of which the primary responsibility is to their shareholders, overseen by a regulator appointed by the UK Government to protect public health. This coincidentally seems to provide an opportunity for a controlled trial of the efficiency of privatisation, and I imagine John Snow and William Budd would have jumped at the opportunity. It is unheard of, however, for politicians actually to put their theories to such a test.
One part of the system works very well both sides of the border – there is no concern about our drinking water and only extremely rarely does some unusual microbe find its way into our taps. But it is clear and acknowledged by the authorities that all is not well on the disposal side. For comparisons to be made, you need to decide on what to measure and to do it in the same way everywhere. But let's start with a hypothesis to test.
Here's one: privatised water management is more efficient at reducing human health hazard than a state-run organisation. Now you have a choice of what to measure, such as recorded diseases, bacterial and viral content of water, and number/volume of discharges. Each presents difficulties, but it should not be impossible to design a suitable study and SEPA and the UK regulator (EPA) should get together and do it. In England, particularly, comparison of the different water companies would quickly influence the payment of bonuses to their directors and their share prices. In Scotland, there is the opportunity of actually measuring the effectiveness of government policy against alternative private enterprises.
Unfortunately, it is not possible to make any comparisons at present, since there are huge differences between the data collected. In England, there were apparently over 300,000 spills of sewage into rivers in 2022 (a dry year) and in Scotland, 14,000 were reported. But in England it appears that 90% of storm outflows were monitored and in Scotland only 3%, so it is possible that, if we had monitored 90% of ours, we could have had over 400,000 spills here (produced by a tenth of the population!). With such a small sample, it is impossible to know but it suggests at least that there is no room for complacency that our system is better than the others – neither is anything other than outdated and ineffective.
This does not imply that we are likely to get an epidemic of cholera or typhoid, since our public drinking water is safe. It does explain why those who swim in open water run a risk of catching one or other of the germs commonly found in human faeces, some of which cause diarrhoea and vomiting, or rarely more serious illnesses. Indeed, one such called Weil's disease is spread by rat urine, so there is nothing we can do to our sewage system to prevent the low risk of this.
In general, the cost to the NHS or to employers of diseases from swimming in contaminated water is probably rather low, while the cost of renewing the entire sewage network is extremely high. Thus, the incentive to tackle the problem is small in comparison to the perceived need to use any money available for other priorities.
The point of view of the providers of contaminated water to rivers and the sea has led to a minimalist response to the protests of swimmers and environmentalists and, it would appear, to a laissez faire attitude of regulatory agencies. Happily now, moral and public health pressure is being exerted and we can expect some movement. In Scotland, any improvement must come from taxation and this competes with other priorities such as social care, NHS and education, to name but three. In England, the money must come from the companies and thus either their profits or their customers, more likely both. Early signs of action include English water company CEOs renouncing their bonuses and SEPA proposing to increase its monitoring activities.
Whatever happens, progress is likely to be slow and if we want clean rivers we are going to have to pay, as our Victorian forebears did. Clean air and clean water may be seen as a human right, though few on this planet receive both. For two centuries we in the rich world have ignored the costs, and they are now becoming apparent. As an environmentalist and taxpayer, I can see the problems and would expect slow progress. As a swimmer, I would make a risk assessment before diving in.
Anthony Seaton is Emeritus Professor of Environmental and Occupational Medicine at Aberdeen University and Senior Consultant to the Edinburgh Institute of Occupational Medicine. The views expressed are his own