Drinking Water Nitrate and Human Health: An Updated Review

• Published in: International journal of environmental research and public health Vol. 15; no. 7; p. 1557
• Main Authors: Ward, Mary H, Jones, Rena R, Brender, Jean D, de Kok, Theo M, Weyer, Peter J, Nolan, Bernard T, Villanueva, Cristina M, van Breda, Simone G
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 23-07-2018; MDPI
• Subjects: Abastament; Adverse reproductive outcomes; Agrochemicals; Aigua potable; Animal manures; Animal wastes; Animals; Aspectes sanitaris; Birth defects; Breast cancer; Cancer; Colorectal carcinoma; Congenital defects; Consortia; Drinking Water; Endogenous nitrosation; Environmental Monitoring; Epidemiology; Europe; Female; Fertilizers; Gene expression; Groundwater; Health risks; Humans; Ingestion; Land use; Methemoglobinemia; Methemoglobinemia - chemically induced; N-Nitroso compounds; Neoplasms - chemically induced; Neural tube defects; Neural Tube Defects - chemically induced; Nitrate; Nitrates; Nitrates - toxicity; Nitrogen; Nitrosation; Nitroso compounds; Nitroso Compounds - metabolism; Pregnancy; Quality control; Review; Studies; Supplies; Thyroid cancer; Thyroid disease; Thyroid Diseases - chemically induced; Trends; United States; Water Pollutants, Chemical - toxicity; Water quality; Water resources; Water shortages; Water supply; United States; Europe; Denmark; Sicily; United States > US; Spain; thyroid disease; methemoglobinemia; adverse reproductive outcomes; cancer; endogenous nitrosation; drinking water; nitrate; N-nitroso compounds
• ISSN: 1660-4601; 1661-7827; 1660-4601
• DOI: 10.3390/ijerph15071557

Nitrate levels in our water resources have increased in many areas of the world largely due to applications of inorganic fertilizer and animal manure in agricultural areas. The regulatory limit for nitrate in public drinking water supplies was set to protect against infant methemoglobinemia, but other health effects were not considered. Risk of specific cancers and birth defects may be increased when nitrate is ingested under conditions that increase formation of
-nitroso compounds. We previously reviewed epidemiologic studies before 2005 of nitrate intake from drinking water and cancer, adverse reproductive outcomes and other health effects. Since that review, more than 30 epidemiologic studies have evaluated drinking water nitrate and these outcomes. The most common endpoints studied were colorectal cancer, bladder, and breast cancer (three studies each), and thyroid disease (four studies). Considering all studies, the strongest evidence for a relationship between drinking water nitrate ingestion and adverse health outcomes (besides methemoglobinemia) is for colorectal cancer, thyroid disease, and neural tube defects. Many studies observed increased risk with ingestion of water nitrate levels that were below regulatory limits. Future studies of these and other health outcomes should include improved exposure assessment and accurate characterization of individual factors that affect endogenous nitrosation.