Water quality standards have declined in two more of Wales’ most protected river networks, bringing the total to seven out of nine river systems failing to meet phosphate level targets.

Environmental groups are calling for “urgent action” to address what they describe as “unacceptable” phosphate pollution in Special Areas of Conservation (SACs).

Natural Resources Wales (NRW), the country’s environmental regulator, reported that two river systems in northwest Wales—Afon Gwyrfai and Afon Eden—previously met phosphate targets but now require further interventions to improve water quality.

The five other rivers failing to meet phosphate standards are the Teifi, Cleddau, Dee, Usk, and Wye.

Phosphates are naturally occurring minerals found in human and animal waste. While they promote plant growth, excessive levels can trigger harmful algal blooms and reduce oxygen levels in waterways, threatening aquatic life.

To curb further phosphate pollution, NRW has announced that housing developments within the Afon Gwyrfai system will face new restrictions. This measure aims to prevent additional phosphate contamination and protect water quality.

In 2021, NRW introduced stricter phosphate pollution targets for SACs in Wales.

Commenting on the latest data NRW Head of Natural Resource Management Mary Lewis said that since then there had been “action at scale – by ourselves as environmental regulators, government, industry and communities – to improve the health of our rivers””.

“What is important now is that we use this evidence to continue to work towards our shared goal of better river health for people and nature,” she said.

“We must keep up the momentum that has been built in recent years, and we must all play our part in driving down phosphorus and pollution in our waters.”

Tim Birch from Wildlife Trusts Wales reiterated the need for immediate and decisive action to safeguard these vital ecosystems.

“Despite public outcry and political promises, today’s evidence shows worsening river pollution in seven of nine of our most protected natural rivers in Wales,” he said.

“These special rivers are officially recognised for their high importance for wildlife, yet two more are now showing significant deterioration since their last assessment in 2021, putting water quality and even more wildlife at risk.

“At a time when our rivers should be improving, not worsening, these levels of phosphorous pollution are unacceptable,” he added.

Of the 122 individual water bodies assessed within these protected rivers, 50% now meet the compliance targets—an improvement from 39% in 2021, though significant concerns remain.