Nitrates in drinking water also pose a risk to human health. The risk of blue baby syndrome in infants is increased when consuming drinking water with Nitrate concentration >11.3mg/L. There is also emerging (though not conclusive) evidence of a link between drinking water Nitrate levels and colorectal cancer risk. Recent international research has found an increased risk of colorectal cancer in drinking water with concentrations >1mg/L, with cancer risk increasing as long-term nitrate exposure increases. Although causation has not been conclusively proven, this risk is a concern in New Zealand and to Waihi Catchment residents as many rural populations’ drinking water is supplied by shallow borewater sources, which can be subject to high Nitrate levels through leaching into groundwater.
Very little Nitrate data in drinking water exists for the catchment. As such, Wai Kokopu has been collaborating with GNS to collect drinking water data from groundwater sources across the catchment. NitrateWatch, a research project by GNS, aims to improve our understanding of Nitrates in drinking water bores and springs nationwide. Wai Kokopu will be working with NitrateWatch in the coming months to improve our understanding of Nitrates in drinking water sources, by collecting and independently testing drinking water from sites across the catchment.