Volunteers have removed kilograms of glass from along the lower Heathcote/Opawaho River, but significant deposits of the often small, but sharp, rubbish remain just below the surface, Jenkins said.
The glass appears to have come from under a riverside path.
The issue has been raised with trust board members and the next step is to talk with Christchurch City Council, she said.
"It is littered with tiny, little pieces of glass.
"There is a lot in an area that is used by families and children - it could be a safety issue, and birds can be easily cut."
Another two big buckets of glass - and four bags of rubbish and small pieces of plastic - have been collected from the area this month by volunteers from neighbouring Ferrymead business, Chiptech.
It adopted a 100m stretch of the river as part of the trust’s drive to encourage nearby businesses to regularly tend to the waterways that discharge into the Avon-Heathcote estuary.
Chiptech product manager Abby Moore said the team of eight was surprised at the “phenomenal” amount of glass found beside such a small section of river just above the bridge.
The worth of their work hit home when Jenkins described how a hector’s dolphin had died nearby after a plastic bottle top got stuck in its blow hole. And she said shags struggle to dive and feed after ingesting polystyrene.
Jenkins said Ferrymead Mitre10 staff also adopted the nearby Charlesworth Wetland reserve a few years ago, which had "made a tremendous difference".
The trust wants to hear from other businesses interested in adopting a section of waterway. Jenkins said she would help with their first clean-up.
- To get in touch with Tanya Jenkins, email info@estuary.org.nz.
