Bio-beads are a hazard to wildlife because they can be mistaken for food, according to the RSPB, which said “any pollution incident of this kind is deeply concerning”.
A spokeswoman for the conservation charity said the beads can “cause blockages that lead to malnutrition where birds feel full because they cannot digest the material”.
Jamie Woodward, professor of Physical Geography at the University of Manchester said the pellets can get “trapped in the gut”, and can be toxic to wildlife if they contain heavy metals and arsenic.
He said: “We don’t know what the concentrations are in this Greater Manchester example, but it would be interesting to know what the composition of these beads is and what sort of contaminants they’re carrying.”