The aim of the paper is to compare nitrate concentrations in samples of supply water as well as

water from deep and dug wells located in the eastern region of Poland. Additionally, samples of bottled water

(spring and natural mineral), certifi ed by the Institute of Mother and Child and the Children’s Memorial Health

Institute, were subjected to analyses. On the basis of the obtained results, health risks related to the occurrence

of methemoglobinemia in neonates and infants were evaluated. The risk analysis was performed according to

the procedure recommended by the United States Environmental Protection Agency. Nitrate concentrations in

the examined samples ranged from: 0.153–161.1 mg/l. The lowest concentration of nitrates was determined in

the samples of bottled water, the highest being detected in the water from dug wells. It was found that nitrate

concentration in samples of bottled and supply water did not pose any risk to the health of neonates and infants.

The highest health risk related to methemoglobinemia occurs for neonates consuming water originating from

dug wells. The risk decreases along with the age of an infant.