Network Rail were quick to reassure locals after grouting materials used to fill abandoned mines was discovered in a Gorebridge burn.
They say that the grout used on the Borders Railway line, which is one part cement to 12 parts ash, is not toxic and invited SEPA in to investigate the discovery at Suzie Dean, close to Powdermill Brae.
All nearby grouting work was immediately stopped.
Craig Bowman, communications manager for Network Rail Scotland said he was happy that the materials used to prevent subsidence were safe.
He said: “We identified unfortunately that some of the grout had made its way underground and into the waterway in the area.
“We invited SEPA along and they are satisfied with what we have done.
“It’s not a toxic material. There is evidence of some material left in the burn, so we are working with SEPA to decide the best method to clear it up.
“They might recommend going in to clear it out or to just let nature take its course as it’s not a toxic material.
“Essentially the pollution has stopped and there is no impact on the local ecology.”
Read more in the September 26 edition of the Midlothian Advertiser.