Nitrate and Nitrite Contamination in Drinking Water: A Systematic Review of the Health Impacts

Nitrate and Nitrite Contamination

Nitrate and Nitrite Contamination in Drinking Water: A Systematic Review of the Health Impacts

The potential health effects of elevated nitrate and nitrite levels in drinking water, particularly their association with cancer, have become a subject of significant interest and concern. In this blog, we will delve into a recent systematic review that sheds light on this critical issue, and we’ll explore the implications of this research for public health. However, in recent years, concerns have arisen regarding the contamination of water sources, particularly from widespread agricultural fertiliser use, leading to increased levels of nitrate and nitrite in drinking water.


What is nitrate and nitrite?

Nitrate and nitrite are chemical compounds found in water and certain foods. They can be harmful in excessive amounts. Nitrate is often used in fertilisers and can enter drinking water sources, while nitrite is formed from nitrate and can have health implications, especially in high concentrations.

To understand nitrogen in water more read our blog that explains the nitrogen cycle!


The Research

The systematic review in question aimed to examine the association of nitrate and nitrite in drinking water with human health, with a specific focus on cancer. The study, conducted by experts in the field, involved a meticulous search of eight databases spanning from January 1990 to February 2021. The objective was to provide a comprehensive analysis of the available literature to understand better the health implications of nitrate and nitrite contamination in drinking water.

Key Findings

  • Out of a staggering 9,835 studies identified in the literature search, the research team found 111 studies reporting health outcomes. Among these, 60 studies were specifically focused on cancer outcomes, encompassing various study designs, including case-control studies, cohort studies, and others. The majority of these studies were conducted in the USA, Europe, and Taiwan, with only a small number originating from low and middle-income countries.
  • Nitrate exposure in drinking water was more commonly investigated than nitrite exposure, with 59 studies addressing nitrate and only four examining nitrite. Among the cancer types, colorectal and gastric cancers emerged as the most frequently reported.
  • The study conducted meta-analyses on four studies, revealing a positive association between nitrate exposure and gastric cancer. Specifically, they found that for every 10 mg/L increment in nitrate ion in drinking water, the odds of developing gastric cancer increased by 1.91 times.


However, the research did not identify any significant association between nitrate exposure and colorectal cancer or cancers at other sites.

Implications and Future Research

The association between nitrate in drinking water and gastric cancer is a significant finding and underscores the importance of addressing nitrate contamination in water sources. While this research provides valuable insights, it’s essential to note that there is currently a lack of robust studies from regions with high levels of nitrate pollution in drinking water. This limitation highlights the need for further research in these areas to gain a more comprehensive understanding of the true health burden associated with nitrate contamination and to inform public policies aimed at safeguarding human health.

Southern Scientific Services’ Role 

Southern Scientific Services is well-positioned to monitor nitrate and nitrite contamination in drinking water. Our company’s expertise in water quality analysis, testing, and monitoring can play a pivotal role in conducting the necessary assessments to better comprehend the extent of the issue in specific regions.

Furthermore, Southern Scientific Services can assist public health agencies and water suppliers in complying with any future regulations or standards that may emerge as a result of these findings. Ensuring safe and clean drinking water is at the heart of our company’s mission, and our dedication to the highest standards of water quality analysis aligns perfectly with the need to address nitrate and nitrite contamination.


  • The systematic review on the association of nitrate and nitrite in drinking water with human health, particularly cancer, has provided valuable insights into the potential health impacts of these contaminants.
  • While a positive association with gastric cancer has been identified, the need for further research in regions with high nitrate pollution levels is evident.


Southern Scientific Services’ role in providing analytical and scientific services is pivotal in advancing our understanding of this issue and in ensuring that clean and safe drinking water remains a fundamental right for all.


nitrate and nitrite

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