The Scottish Environment Agency (Sepa) has taken steps to investigate whether the train crash has impacted the local water supply.
On Wednesday, local farmers raised fears that diesel from the damaged carriages could have leaked into the River Carron, which flows into Stonehaven.
Now, Sepa has confirmed that its officers have deployed barriers to protect the water from any hydrocarbons – which are naturally-occurring compounds and form the basis of crude oil, natural gas, coal, and other important energy sources.
A spokesman said: “Sepa continues to support the multi-agency response following Wednesday’s tragic incident near Stonehaven. Our thoughts remain with all those involved in the incident.
“We are working to minimise impact on the local environment and are in contact with Network Rail who have confirmed that an oil boom has been deployed in the River Carron to collect any hydrocarbons released.
“We will also continue to provide any environmental advice and assistance, as required, going forward.”
On Wednesday, between the hours of 6am and 1oam, Sepa recorded 79mm at their rain gauge at Dunnottar.
Aberdeenshire Council confirmed it was “aware that the boom is in-situ”.