"This environmental tragedy wasn't an isolated incident."
Police are aware of the suspect's identity, who is believed to have fled to Southland.
"The glass could go through her wee shoes, or if she tripped, she would get cut hands."
The council's pollution team visited the site at Kaikorai stream and have taken water samples for testing.
"A single spike in blood isn't going to be a huge problem."
Unsafe lead levels have been detected in children's blood tests in east Otago.
On Friday water supply in two Otago towns was found to contain traces of lead 40-times the acceptable level.
Mt Iron, to the east of the Wānaka township, is surrounded by highly combustible native kanuka.
People in Waikouaiti and Karitane were told not to use tap water for drinking or cooking due to high lead levels.