What lurks in Dunedin’s Water of Leith was examined by a trio of Columba College students and their investigation won them the premier award at the Otago science fair.

The best-in-fair prize was won by year 12 students Ava Wilson, Zoe MacKenzie and Emily Berry.

“What lies beneath the Leith” was their choice of subject and they looked into pollutants such as microplastics, Aurora Energy Otago Science and Technology Fair convener and judge Dr Steven Sexton said.

“Like most things, the water’s not as clean as it probably should be,” he said.

The fair was open to year 7 to 13 students in Otago.

Dr Sexton said there were 255 entries from 14 schools — 315 students participated.

Judging took place early last week, there was then a period for the public to view the entries in Dunedin and prizegiving was on Sunday.

About 40 prizes were up for grabs in fields ranging from anatomy to zoology.