Greenpeace Aotearoa is warning that high levels of nitrate in the town drinking water supply at Tokoroa could pose health risks, following a free drinking water testing event that the organisation ran yesterday.

The testing found that the town’s water supply consistently tested at over 3 mg/L of nitrate (NO3-N). This was consistent with South Waikato District Council monitoring data, which showed nitrate levels of 4.11mg/L for the most recent sample in 2019.

This is significantly higher than the majority of New Zealanders’ drinking water - around 80% - which has nitrate levels below 1mg/L.

Greenpeace spokesperson Amanda Larsson says, "Everybody should be able to safely drink the water coming out of their kitchen tap without worrying that it will make them sick. It’s concerning that communities like Tokoroa have such high levels of nitrate contamination in the town-supplied drinking water."

Emerging evidence shows bowel cancer risk increases from long-term exposure to nitrate in drinking water as low as 1mg/L. Higher levels of nitrate mean greater health risk..

According to other studies, nitrate levels above 5mg/L while pregnant may increase risk of preterm birth, reduced birth weight, congenital abnormalities and neural tube defects. The Ministry of Health warns that "If you are pregnant, high nitrate levels may reduce the amount of oxygen getting to your pēpi."

Council testing from 2019 reveals that nitrate contamination of the Tokoroa town supply has reached levels as high as 4.11 mg/L - nearing levels that increase the risk of preterm birth.

"Safe drinking water is a basic human right. But nitrate contamination in New Zealand’s drinking water threatens that right, and levels of nitrate contamination have been increasing across the country since the 1990s," says Larsson.

"Unfortunately, people in rural areas are at higher risk of nitrate contamination in their drinking water, as they are more likely to live near intensive dairying. Synthetic nitrogen fertiliser and cow urine from dairy farms are the main sources of nitrate contamination of drinking water.

"The Government has a responsibility to ensure that everyone, no matter where they live, can safely drink the water coming out of the tap. That means phasing out synthetic nitrogen fertiliser, lowering cow numbers, supporting farmers to transition to organic, ecological farming, and keeping the current water protection rules in place - not repealing them.

"If you’re wondering whether you could be at risk, you can visit our Know Your Nitrate map to see the levels of nitrate contamination in drinking water in your area. The only way to know how much nitrate is in your personal drinking water supply is to have it tested. We encourage people to get their drinking water tested if they’re concerned via our free mail-in water testing."

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