Hon DAVID PARKER: I think it's astounding that between 1990 and 2015 there was, from memory, a more than 600 percent increase in synthetic nitrogen fertiliser application in New Zealand, and that that, together with the more intensive livestock practices, with more livestock per hectare, there has been a remarkable increase in New Zealand in nitrates, both on the land and in our waterways. That has contributed to environmental problems in our rivers, including the overgrowth of periphyton slime, and also nitrate toxicity levels which, at times, hinder a wide range of aquatic communities.