Science / Environment

Natural state? Water purity measure corrected

09:39 am on 20 July 2021

The equation for measuring water purity has been corrected but a freshwater ecologist questions whether this adjustment is sufficient to prevent pollution. The official equation measuring the human impact on groundwater has been revised to better reflect levels of pollution. 

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Water scientist Dr Mike Joy has been campaigning for years to get the Ministry of the Environment to adjust the way they measure water purity. He has had something of a win. Admitting they had the figures wrong, Stats NZ has downgraded the 3 grams of nitrate allowed per cubic metre of water for it to be considered in a "natural state". Dr Mike Joy joins Kathryn to discuss why these measures are so important. 

Algal bloom on Lake Forsyth Photo: Fish & Game New Zealand