Spring WaterBlitz reveals widespread water pollution in freshwater environments across Thames Valley, Luxembourg, Paris and Dublin

3rd June 2021

A report published today by Earthwatch Europe reveals that levels of phosphates and nitrates (key indicators of the health of a waterbody) were elevated in a large number of waterbodies measured by volunteers over the Early May Bank Holiday weekend. The results identify that:

52% of all waterbodies measured had a high nitrate concentration and 23% had a high phosphate concentration indicating that water pollution is a widespread issue
The Thames Valley had the largest percentage of samples with high levels of nitrates (c. 70%). The area consistently has a higher count of high nitrate in samples, compared to the UK average. Nitrates are commonly associated with agricultural pollution, so these high levels could be linked to the large amount of fertilizer used on the land in the area, today and in the past.
Luxembourg had the largest percentage of samples with high levels of phosphates (c. 28%). Phosphates tend to come from organic matter like manure and sewage. They can have a disproportionate impact on smaller waterbodies, which are especially common around Luxembourg city.
Over a quarter of test sites in Dublin (26%) the highest percentage of the three locations recorded litter in or near the water. Litter is a pollutant and can be a danger to wildlife.
In Paris, 37% of the waterbodies measured showed a high concentration of nitrates and 19% showed a high concentration of phosphates. Only 1% of the waterbodies measured in Paris were located near agricultural land, which could explain why, compared to the other three locations, nitrates appear to be quite low in the area.

This is the eleventh WaterBlitz event to be held in the Thames Valley, and the second time it has been held in Luxembourg, Paris and Dublin. This event was made possible through Earthwatchs partnership with Royal Bank of Canada (RBC).

The results echo the findings of previous events, suggesting that these conditions are not a one-off.

Repeat records with elevated phosphates and nitrates indicate that many of the sampled waterbodies might be eutrophic. This means that they have a high nutrient load, which can cause algal blooms. In turn, these algal blooms can cause oxygen deprivation in the water and therefore kill fish and submerged plants. Eutrophication can cause a chain reaction of events that are detrimental to the ecosystems health. The fact that we are seeing high concentrations of nutrients in so many waterbodies across multiple locations is very worrying because these chains are very hard to break.

The results also provided some more positive news. Many volunteers surveyed smaller waterbodies, such as small ponds or tributaries, which are often not included in the routine monitoring done by water companies or the Environment Agency. These areas are often known and cared about by local residents who have a more personal relationship with them and can provide observational evidence of their condition. Including these smaller waterbodies creates a more complete picture of the overall water quality and allows local residents to take action if needed.

One WaterBlitz participant in the Thames Valley said: The results confirmed that my local water source was quite healthy which I had some idea would be the case due to the number of wildlife living around it and in it. This is an observation that may not have been picked up in routine monitoring and proves that despite the high levels of pollution overall in the area, there are still pockets of cleaner water.

Isabel Bishop, Freshwater Research Lead, adds: It was amazing to see so many people taking part in this WaterBlitz, the biggest of these events to date.

It would be impossible for professional scientists to collect a similar snapshot of conditions without the help of volunteers. The results clearly show the locations of pollution hotspots as well as oases of clean water. Changes to environmental policy or laws require a lot of evidence, and we are hopeful that the data we have collected will contribute to more targeted protection for our waterways.

We want to extend a huge thank you to everyone who contributed.

You can find the full report here.

You can see the integrated data map here.