Environmentalists in Uttlesford have raised concerns about the levels of phosphate pollution in the River Cam, which they say has "confirmed their worst fears".

For the past two years, district councillor Richard Pavitt - who lives in Great Chesterford - has used a handheld device to test the river, which showed phosphate levels are 55 times over the acceptable limit.

Cam Valley Forum, a Cambridge-based river group, provided laboratory testing to validate his results, and also took samples at eight points along the river, which were sent to South East Water Scientific Services.

The results confirmed the major source of phosphate contamination is water recycled by sewage treatment works at Quendon, Newport and Great Chesterford - which Cllr Pavitt says points to "serious neglect" by Anglian Water and the Environment Agency.

He said: "Why has it taken so long for anyone to pay attention to the damage this is causing? It is a prime example of a dysfunctional planning system that does not allow for the cumulative impact of development.

"There is also a major problem with the EA that has long ceased to be pro-active. The agency has been defunded and told not to stand in the way of development.

"I suspect we will find similar pollution in Uttlesford’s other rivers where investment in sewage treatment works has not kept pace with housing development."

Human effluent, detergents and other household substances contain phosphate, a nutrient that accelerates algal and fungal growth, robbing river water of oxygen.

An Anglian Water spokesperson said: "Our Quendon and Newport sewage treatment works will be upgraded to reduce phosphate concentrations entering the River Cam by the end of 2024.

"These works were included in Anglian Water’s £800m environmental investment programme for the five years from 2020 to 2025. 

"This is our largest ever environmental investment programme, and we worked closely with the Environment Agency to undertake detailed scientific modelling and analysis of river water quality to identify priority sites for action to reduce nutrients. 

"Reducing phosphate concentrations at wastewater treatment works to below 0.25 mg/l is also regarded as unachievable from a technical perspective and a catchment-wide approach, looking at all sources of phosphate is the most appropriate way to minimise the risk of excess nutrients.

"We will continue to engage and work with the Cam Valley Forum, the Cam Upper Reaches Action Team (CURAT) and others to identify what work is required at other smaller sites in the Cam Valley, including the identification and reduction in other sources of phosphate."

An Environment Agency spokesperson added: "Where environmental laws are breached, the Environment Agency will take enforcement action, up to and including prosecution.

"We have significantly driven up monitoring and transparency from water companies in recent years by increasing the number of overflows monitored, with 15,000 overflows set to be monitored by 2023. We expect water companies to deliver on the promised £4.6bn investment (2020-2025) to protect and enhance rivers and beaches.

"We encourage members of the public to report all environmental incidents to our incident hotline number 0800 807060 so we can investigate."