Environmental groups are telling the government it is imperative to lower the limit on the amount of nitrate pollution allowed in New Zealand's waterways. They say restricting nitrate levels to under one milligram per litre is essential for protecting the health of humans and native species. The limit was left out of last year's freshwater standards and is now being reassessed by the Ministry for the Environment. Spokesperson for Choose Clean Water Marnie Prickett speaks to Māni Dunlop on Midday Report.