Key Takeaways
- Nitrate levels in Waimate district water supplies are increasing, with recent tests showing 8.8 mg/L of nitrate-nitrogen
- The legal limit for nitrate-nitrogen is 11.3 mg/L, but health advocates recommend an alternative water source for pregnant people if levels exceed 5mg/L
- Nitrate contamination has been linked to an increased risk of preterm birth and bowel cancer
- The Waimate District Council has been working to address the issue, including plans to tap a new, lower nitrate water source
- The intensive dairy industry is seen as a major contributor to the nitrate pollution in the area
Introduction to Nitrate Contamination
Nitrate levels in the Waimate district water supplies have been testing high, with recent results showing 8.8 mg/L of nitrate-nitrogen. This is a concern for the community, as nitrate contamination in drinking water has been linked to an increased risk of preterm birth and bowel cancer. The New Zealand College of Midwives has advised pregnant people to consider an alternative water source if their primary water source is above 5mg/L of nitrate-nitrogen. The legal limit for nitrate-nitrogen is 11.3 mg/L, but some health advocates are pushing for this limit to be lowered due to the potential health risks associated with nitrate contamination.
History of Nitrate Contamination in Waimate
The Waimate district has a history of nitrate contamination issues. In late 2022, around 650 households were told their tap water was unsafe after nitrate levels in the Waihao and Waikakahi East rural water schemes exceeded the maximum allowable value. Again, in December 2024, residents were advised not to drink the water after it breached the limit. The council provided water tanks and diluted the supply with water from the Waitaki River, but this was not a long-term solution due to the presence of didymo algae and sediment in the river. The council has since been working to address the issue, including plans to tap a new, lower nitrate water source, with work expected to start in 2026.
Causes of Nitrate Pollution
The intensive dairy industry is seen as a major contributor to the nitrate pollution in the Waimate district. Greenpeace Aotearoa spokesperson Will Appelbe stated that "the only way to permanently improve nitrate contamination is to address the source of the pollution: the intensive dairy industry." The use of fertilizers and animal waste in the dairy industry can lead to high levels of nitrate in the soil, which can then leach into groundwater and contaminate water supplies. The Waimate District Council has been working to reduce the contamination, but it is a complex issue that requires a comprehensive approach to address the root causes of the problem.
Regional Response to Nitrate Contamination
The Canterbury regional council has also been addressing the issue of nitrate contamination in the region. In September, the outgoing council narrowly voted to declare a nitrate emergency, which was met with criticism from government ministers and farming groups. However, research by Earth Sciences New Zealand found that the region had the highest percentage of elevated nitrates in groundwater in the country. The council’s most recent annual groundwater testing found that nitrates had increased during the past ten years in 62 per cent of test wells. This highlights the need for a regional approach to addressing the issue of nitrate contamination, and for government and industry leaders to take action to reduce the levels of nitrate in the environment.
Conclusion and Future Steps
The issue of nitrate contamination in the Waimate district is a complex one that requires a comprehensive approach to address. The Waimate District Council and the Canterbury regional council are working to reduce the levels of nitrate in the water supplies, but it will require a long-term commitment to addressing the root causes of the problem. The intensive dairy industry must take steps to reduce its impact on the environment, and government and industry leaders must work together to develop policies and practices that prioritize the health and well-being of the community. By working together, it is possible to reduce the levels of nitrate in the water supplies and create a healthier and more sustainable environment for the community.