Whether you live in New Zealand or are visiting this country, it is important that you understand the dangers of nitrates in drinking water. Nitrates can cause colorectal cancer and may contribute to other health issues, including foodborne illnesses.
Sources of nitrates in New Zealand’s drinking water
Despite the recent approval of New Zealand’s National Environmental Standard for Drinking Water (NES-DW), there is still some uncertainty as to whether drinking water contaminated with nitrates is safe to drink. This briefing will review the latest evidence on nitrate contamination and human health risks.
Nitrates are nitrogen-containing compounds that are found in groundwater and soils. They can be hazardous to humans and animals when in large amounts. The most common sources of nitrate are agricultural runoff, wastewater treatment plants, and leaky septic systems. Agricultural intensification has resulted in increased nitrate contamination in drinking water sources.
High nitrate concentrations in groundwater have been found in many regions, including Canterbury and the Waikato. These regions are especially susceptible to the problem. The median nitrate concentration in shallow groundwater is two times the average of all monitored groundwater. The highest nitrate concentrations are found in well-oxygenated groundwater in unconfined aquifers.
Recent studies have found a link between elevated nitrate levels and various cancers. These studies suggest that high nitrate levels may increase the risk of bowel cancer. However, further research is needed to confirm this link.
The risk of infant methemoglobinemia is increased when nitrates are present in water. This condition can cause the blood to fail to deliver oxygen to the brain, resulting in death.
Increased risk of colorectal cancer
Several international epidemiological studies have indicated a link between ingested nitrates from drinking water and an increased risk of colorectal cancer. Nitrates are primarily derived from agricultural fertilizers. They enter waterways through animal urine, rain and irrigation. The human body then converts nitrate into carcinogenic N-nitroso compounds. The pH of the stomach acid can also affect the conversion of nitrate to carcinogenic compounds.
In Aotearoa New Zealand, the drinking water limit is set at 11.3 mg/L. It has been calculated that 300,000 to 800,000 Kiwis may be exposed to potentially harmful levels of nitrates in drinking water. These levels could contribute to an estimated 40 deaths and 100 cases of bowel cancer each year. Agricultural intensification has increased nitrate levels in drinking water sources and surface water.
Nitrate contamination in drinking water could also increase the risk of preterm birth in pregnant women. A recent US study found that nitrate could increase the risk of preterm birth from five to 10 mg/L. Nitrate levels in groundwater are estimated to be at least three times higher than the threshold level for colorectal cancer risk.
A large Danish study has also shown a link between nitrates drinking water NZ and an increased risk of bowel cancer. The study, which involved a cohort of older women, found a link at 0.87 mg/L of water.
Preventing foodborne illness
Keeping food safe involves a combination of preventive measures. This includes proper handling, cooking and storage. In addition, it is important to know what nitrates and nitrites are and how they can affect your health.
Nitrates are a naturally occurring compound with one nitrogen and three oxygen atoms. They are used to add flavor to meats. They have been linked to some health benefits, but they also can have negative side effects. They can interfere with the oxygen carrying capacity of the blood. When they are broken down, they can form nitrosamines, which can cause cancer. They are also known to be harmful to infants.
Infants under six months of age may be especially susceptible to nitrate-related illness. They have less acidic stomach juices, and they are more susceptible to the growth of nitrate-reducing bacteria.
The United States has some of the safest food supplies in the world, but there is still a lot of work to do to protect the public from food contamination. The Food Safety Modernization Act has introduced additional methods to help prevent food contamination.
Nitrates are found in some Minnesota lakes. They are also present in groundwater. If you drink water with high nitrate levels, you may be at risk for methaemoglobinaemia, which can lead to death within a few days. This condition is caused by the conversion of nitrate to nitrite.