Pollution levels double the legal limit have been found on the South Downs.

A number of authorities are keen to solve the problem before it becomes critical after nitrate levels of 100 milligrammes per litre (mg/l) were registered in places across the chalk hills of the national park.

The water from the South Downs is always treated before it reaches the 1.2 million people who rely on it for drinking water, but the continued rise in contamination means the cost of purifying it is also rising.

Chris Manning, a research and evidence officer at South Downs National Park Authority, said: “Nitrate levels are manageable, but we think we can do better.

“The legal limit of nitrate in drinking water is 50mg/l but we want to keep this figure much lower by being proactive so we don’t have to go down the route of these drastic measures that cost a lot of money to achieve safe drinking water.”

£80,000 will be spent funding a network of monitoring, which is hoped will locate the source of the nitrate, potentially saving the water companies and taxpayers millions of pounds.

Combat A number of authorities have joined forces in an attempt to combat the problem, including the Environment Agency and the Downs and Harbours Clean Water Partnership.

They believe tracing the source |of the nitrate is the only viable |solution.

Huge operation

A spokesman from the Downs and Harbours Clean Water Partnership said: “Essentially we have two other options.

“One is to fork out £2 million to £3 million for a huge-scale operation to purify the water.

“The other is to blend water that has high levels of nitrate with water that has low levels of nitrate to reach an acceptable level.

“But we want to stop more nitrate getting in as opposed to going down those routes.”

Wessex Water has introduced a successful scheme to combat the same problem by paying farmers to abide by sustainability measures.

Mr Manning said: “We don’t have enough evidence at the moment, and what this project aims to do is provide us with enough evidence so that we know the measures to employ to combat the problem.

“The nitrate could be coming from any one from a whole raft of sources – it could be fertiliser, cattle, septic tanks – and that’s the battle.”

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