Parts of Loch Lomond could be at risk from pollution

Water quality analysis by the Scottish Environment Protection Agency (Sepa) found evidence of harmful nutrients from sewers, farms, and salmon cages.

A spokesman said in severe cases oxygen in the water was reduced, causing fish and other aquatic life to die.

The under-threat areas were identified to help target additional protection.

Sepa has designated 146 rivers and 17 lochs in 82 areas as being "sensitive" to pollution.

Damage limitation

The areas extend across the country and include the River Annan in the south west, Loch of Harray in Orkney, parts of the River Tweed, the lower Clyde and the southern basin of Loch Lomond.

Pollution comes from sewage treatment works as well as fertilisers and animal wastes washed off farmland and faeces deposited by fish farms.

Sepa director Colin Bayes said: "These effects are difficult to reverse, so it's important to take action early to limit the damage."

Sewage will be given additional treatment before it is discharged

He said Scottish Water had been charged with providing additional treatment to reduce the level of nutrients in effluent before it was discharged.

However, he said it would be more difficult to control nutrients discharged from farm land.

"We will need to work with the agricultural industry in tackling the problem and hope to do so co-operatively rather than rely on the new powers granted to Sepa under European legislation," he said.

Deputy Environment Minister Rhona Brankin said the move had increased "sensitive area" status twenty-fold.

She said: "Together with Sepa and Scottish Water, we are applying appropriate means to improve the standard of urban waste water treatment to protect sensitive areas."