Political parties will be grilled over nitrate in Canterbury’s drinking water at a freshwater debate in Christchurch next week, less than three weeks before the election.

Greenpeace is hosting the Great Freshwater Debate at The Piano on Armagh Street on Monday, 19 October, from 7pm.

Labour, the Greens, The Opportunity Party and New Zealand First have confirmed they will take part, and organisers are working to secure representatives from National, ACT and Te Pāti Māori.

Greenpeace campaigner Rhiannon Mackie said many rural families in Canterbury could not drink the water from their taps without worrying about getting sick.

“Canterbury has some of the highest drinking water nitrate levels in the country.”

Greenpeace has tested thousands of water samples from town supplies and private bores, and its highest readings were consistently around areas with large dairy herds, including Canterbury, she said.

Public health researchers in New Zealand and overseas were linking nitrate in drinking water to a higher risk of bowel cancer and preterm birth, at levels well below the current drinking water standard, Mackie said.

“With thousands more dairy cows consented for the Canterbury plains, this problem is going to get worse unless we see political action to protect people’s drinking water.”

Mackie said the Government had gone backwards by dismantling freshwater protections, and official information documents showed lobby groups such as Federated Farmers had pushed for them to be weakened.

She also accused Environment Canterbury of passing responsibility for nitrate contamination back to central government.

Greenpeace wants an end to new dairy expansion, including large irrigation schemes, along with a phase out of synthetic fertiliser and smaller dairy herds.

Next year the Government will finish a review of whether the health limit for nitrate in drinking water should be lowered. Mackie said that decision would affect Canterbury families for generations.

The debate will be moderated by journalist David Williams. It will be followed by an expert panel made up of former Greens co-leader Russel Norman, freshwater researcher Marnie Prickett, Gabrielle Huria of Ngāi Tahu and Andrew Mockford of Irrigation New Zealand.

Mackie said the debate was open to everyone, not just Greenpeace supporters.

Doors open at 6.30pm. Questions can be sent in advance to [email protected], and tickets are available at community.greenpeace.org.nz/events/the-great-freshwater-debate.