Dog owners are being warned to keep their pets out of a polluted river after five swans were taken to a rescue centre for treatment.
East Lothian Council has issued the warning to people as work continues to tackle the spill in the River Esk, Musselburgh.
Wildlife officers at the Scottish SPCA said they found several birds had been affected by the spill which locals described as having a 'strong petrol' smell after it was first spotted on Friday.
Environment agency SEPA has urged anyone with information about the spill, which has been traced to a manhole which leaked contaminated materials into the water, to contact Crimestoppers as the investigation into the incident continues.
The spill into the River Esk, in Musselburgh was first spotted by East Lothian Council's countryside rangers on Friday lunchtime and emergency operations were launched to identify the source and limit the spread.
Locals shared disturbing images of polluted water on social media with complaints about an unpleasant smell coming from the water.
The Esk is renowned for its swan and geese inhabitants who are regularly seen in the water and on the surrounding banks in Musselburgh town centre.
Scottish SPCA senior inspector, John Toule, said: "We have so far uplifted five swans and taken them to our National Wildlife Rescue Centre to receive the care they need.
“As we need to protect the birds we already have on site from bird flu, we are limited in how many we can take at a time.
“We are continuing to monitor the situation and will keep providing care to the birds as space allows."
East Lothian Council and SEPA officers worked through the weekend to deal with the spill with absorbent pillows and boom barriers being used to try and reduce the impact.
The local authority said it had brought in a specialist contractor to help contain the spill and it warned pet owners to keep their dogs out of the water as well as issuing warnings to local anglers.
A council spokesperson said: "This pollution incident has been very concerning for local communities.
"We are very grateful to local people for their support and understanding during this incident."
Anyone concerned about wildlife on the river can contact the SSPCA helpline on 03000 999 999.
