Investigation launched into River Dee ammonia pollution
An investigation has been launched after unusually high levels of ammonia were found in the River Dee.
Parts of the river were closed over the weekend in order to protect the drinking supply.
Natural Resources Wales (NRW) said ammonia levels were returning to normal and "initial assessments" showed no signs of dead or distressed fish.
Agencies have called for any information that could help identify the source of the pollution.
Mark Chapman, from NRW, said: "Although we've taken many water samples and visited premises in the area, we've not yet been able to confirm if this pollutant has originated from farming practices or from industrial activities."