Hundreds of ordinary people sampled rivers in Wales and this is what they found

North Wales Live

4 days ago

Rivers in southern Gwynedd are amongst the cleanest in the UK, a citizen science initiative has revealed. Elsewhere in Wales, water quality is poorer – but nowhere near as bad as in England.
This year's Great UK WaterBlitz showed that 37% of water samples in Wales contained unacceptable levels of nutrient pollution, compared to 74% in England. No nutrient pollution – nitrates and phosphates – were found in any of Meirionydd's rivers.
The Llŷn and Eryri river basin fared well too, with just 12% of sampling points showing significant levels of nutrient pollution. For the Tawe to Cadoxton catchments in southwest Wales, the figure was around 27%.
However, water quality was poorer elsewhere. In the Dee catchment, nutrient pollution was measured at 40%, while on Anglesey 43% of the island's rivers were found to be degraded. A little better, but still failing, was the Teifi and North Ceredigion river basins (48%).
Worst offender were the Cleddau and Pembrokeshire Coastal Rivers where nitrates and phosphates were found in almost seven in 10 waterways.
Across the UK, the worst places for water quality were the Thames and Anglian river districts. Here, fewer than 14% of measurements showed clean water based on 1,335 samples.
While Wales compared favourably with England, the country's 37% failure rate was worse than in Scotland and Northern Ireland (both 30%).
Dr Sasha Woods, director of science and policy at Earthwatch Europe, said the UK-wide picture is one of rivers 'suffocating under relentless pollution - sewage, tyre particles, fertilisers'.
She added: 'While the situation in Wales is better than in England, over half of the sites tested in Wales still show unacceptable levels of pollution. This demonstrates a clear need for action to address the issues impacting Welsh rivers and protect these vital resources.'
Nitrates and phosphates occur naturally in the environment and are essential for plant growth. But high concentrations cause excessive growth which decreases oxygen concentrations, negatively impacting aquatic plants and animals.
According to Environment Agency figures, farming accounts for 50-60% of nitrate pollution while sewage effluent contributes 73% of phosphates.
The Great UK WaterBlitz, organised by Earthwatch Europe, saw 7,978 citizen scientists test 4,017 freshwater sites in the UK late April.
For the study, E coli bacteria levels were also measured in 301 sites. Of these, 24% indicated the water was too poor to swim in.
Earthwatch Europe found a link between E coli and phosphate (sewage) levels, but not between E coli and nitrate levels. Sign up for the North Wales Live newsletter sent twice daily to your inbox
Separate surveys are carried out for bathing waters off the UK coast – in Wales these are overseen by Natural Resources Wales. The 44 North Wales beaches that are best and worst for swimming can be found here.