Understanding The Threat of Drinking Water To River Ecosystems

Written by CEO Laura Owen Sanderson

The quality of our tap water and rivers is not only critical for our own well-being but also for the environment. But there is a hidden danger lurking in our waters that could put our rivers at risk - phosphorus.

So, why is it added to tap water in the first place, and what happens when it leaks into our rivers?

In the UK, phosphorus is routinely added to drinking water supplies in a form known as phosphate. It is added to effectively prevent any lead entering the water supply, which can come from the corrosion of old piping. Lead is a toxic metal and adding phosphate has proven to be very successful in reducing human exposure to it.

But just what is the fate of this phosphate?

Latest statistics show that the biggest UK water utilities lose around 25 per cent of drinking water to leakage – or around 40 litres per customer per day. Based on the amount of phosphate which is presently added to tap water, this is equivalent to around 1200 tonnes of phosphorus entering the environment every year.In this article, we will explore the dangers of phosphorus, its impact on our water systems, and what we can do to mitigate the risk before it's too late. It's time to take this issue seriously, and together, we can protect our water resources for generations to come.

The Finite Resource of Phosphorus: Phosphorus is an essential element that is crucial for plant growth and is often used in fertilisers to enhance agricultural productivity. However, phosphorus is a finite resource, and its availability is limited. In fact, phosphorus is a non-renewable resource, and its reserves are estimated to be declining globally. This scarcity of phosphorus is a growing concern as it has significant implications for food security and sustainability.

Anthropogenic, or man-made, inputs of phosphorus are well known to have a significant impact on ecosystems, and can damage the health of rivers and lakes (known as eutrophication). What ultimately happens to phosphate after leakage is currently unknown.

So why is it in our tap water?

Water companies add copious amounts of phosphorus to tap water as a corrosion control measure. Phosphorus can form a protective layer on the inside of pipes and fixtures, reducing their corrosiveness and minimising the leaching of metals, such as lead and copper, from plumbing systems into drinking water. This practice is justified in order to protect public health by ensuring that tap water is safe to drink and that the plumbing infrastructure is not deteriorating.

However, there are concerns about the presence of phosphorus in tap water. When tap water containing phosphorus is discharged into rivers and other bodies of water, it can contribute to the eutrophication of water bodies. Eutrophication is a process where excessive nutrients, including phosphorus, promote the growth of algae and other aquatic plants. This can result in the formation of harmful algal blooms, which can have severe impacts on water quality, aquatic ecosystems, and human health.

The Impact of Leaking Freshwater Pipes on Rivers: Leaking freshwater pipes can be a significant source of phosphorus pollution in rivers. Old and deteriorating water distribution infrastructure can lead to pipe leaks, allowing phosphorus-rich tap water to seep into surrounding soil and eventually make its way into rivers through runoff or groundwater. This can result in elevated phosphorus levels in rivers, contributing to the nutrient load and exacerbating eutrophication.

The impact of phosphorus pollution from leaking freshwater pipes on rivers can be far-reaching. High phosphorus levels can stimulate the growth of algae and aquatic plants in rivers, leading to the formation of dense mats of vegetation that can impede water flow, reduce oxygen levels, and disrupt the natural balance of aquatic ecosystems. These changes can negatively impact fish and other aquatic organisms, leading to declines in biodiversity and the degradation of river ecosystems.

Scientists warn of ‘phosphogeddon’ as critical fertiliser shortages loom: Phosphorus is a finite resource that plays a crucial role in food production and water treatment. Phosphorus was discovered in 1669 by the German scientist Hennig Brandt, who isolated it from urine, and it has since been shown to be essential to life. Bones and teeth are largely made of the mineral calcium phosphate – a compound derived from it – while the element also provides DNA with its sugar phosphate backbone.

The element’s global importance lies in its use to help crop growth. About 50m tonnes of phosphate fertiliser are sold around the world every year, and these supplies play a crucial role in feeding the planet’s 8 billion inhabitants.

However, significant deposits of phosphorus are found in only a few countries: Morocco and western Sahara have the largest amount, China the second biggest deposit and Algeria the third. In contrast, reserves in the US are down to 1% of previous levels, while Britain has always had to rely on imports.

Why are Dwr Cymru adding it to tap water? While adding phosphorous to tap water is necessary for corrosion control, the discharge of phosphorus-rich tap water into rivers can contribute to eutrophication and have detrimental effects on water quality and ecosystems.

It is imperative to manage phosphorus use in water treatment and minimise phosphorus pollution from leaking pipes to protect our tap water and rivers from the hidden dangers of phosphorus contamination.

The issue of phosphorus in tap water and rivers requires careful attention and management to prevent adverse impacts on water quality, aquatic ecosystems, and human health. As a society, we need to prioritise sustainable phosphorus management practices, including reducing phosphorus use, improving water treatment processes, and addressing leaking freshwater pipes.

Check your pipes at home for leaks. If you notice the water pressure is low you may have a leak. Actively look for signs of leaks when you are out and about. The solution is to replace all of the freshwater pipes across Wales. But with costs rising and sewage high on the agenda this isn’t going to be a top priority for our water boards.

Our role at NWRT is to educate the public about this silent polluter for our rivers, raise awareness and educate the community so you can identify leaks quickly and efficiently and campaign for new infrastructure across Wales for both sewage and freshwater.

READ MORE ABOUT RESEARCH ON TAP WATER AND THE EFFECT ON THE ENVIRONMENT HERE.