Photo: RNZNew research has found there is not enough rain and river water in Canterbury to dilute nitrate pollution from dairy farming to acceptable drinking water standards. Canterbury's nitrate grey water footprint - the amount of water needed to dilute nitrogen leached past the root zone - ranged from 433 to 11,110 litres of water per litre of milk, depending on the water standards applied, the the study found. Nitrate levels at three quarters of the groundwater sites in Canterbury were significantly increasing, while eight percent of the sites were exceeding the maximum allowable value for nitrate in drinking water. High levels of nitrates in drinking water have been linked to an increased risk of colorectal cancer and birth defects. The Ministry for the Environment is currently considering changes to the national environmental standards for sources of human drinking water.

Source: Otago Daily Times May 29, 2022 22:40 UTC