Police are appealing for information after a 'significant amount' of Stanley knife-type blades and broken glass were dumped at a beauty spot.
It is believed to have happened several times in the past.
In the latest incident, at least 30 blades were found near Valehouse Reservoir in Tintwistle.
The reservoir is a popular spot with local dog walkers.
In a post on Facebook Glossop Police said: "We have received reports regarding a significant amount of Stanley knife type blades and broken glass being left on land which is adjacent to the Disabled Pier at Valehouse Reservoir at Tintwistle.
"This we believe has occurred at the same location several times.
"We ask that if you have any information that can assist the Police with their enquiries, or if you know who may me responsible, then please contact us."
Anyone with information is asked to call police on 101 quoting reference number 2000486566 or Crimestoppers anonymously on 0800 555 111.
