A new study has revealed just how high the levels of nitrate are in our water supply.
Research published in the Journal of Hydrology shows nearly 60 percent of New Zealand’s freshwater sources could be tainted with nitrate.
The report has cast fresh concerns over the health risks of nitrates, with researchers worrying over a link with bowel cancer.
Massey University Professor of Agriculture Doctor Jacqueline Rowarth told Mike Hosking that she's not convinced about that.
She says she doesn't believe current levels of nitrate are a major problem.
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