Greenpeace Aotearoa has found two thirds of farm water bores tested had nitrate levels above those linked to bowel cancer in an international study. Greenpeace released the preliminary results of its mail-in nitrate water testing service which tested 300 mail-in samples, including 237 from unique bore water supplies. The results showed 68 per cent of those from bores were over the 0.87 milligrams per litre limit linked to bowel cancer in a major Danish study published in 2018. Greenpeace’s testing also found five per cent exceeded the current drinking water standard of 11.3mg/litre. Most nitrates in New Zealand’s water come from dairy farming runoff. Farmers use synthetic nitrogen fertilisers to add nutrients to the soil, some of which were then ingested by cows and make their way through the water system. Greenpeace wants the Government to ban synthetic nitrogen fertiliser, end new dairy conversions, and set stock limits for dairy cows.