Nitrites in public drinking water in the province of Zamora

Abstract

Elevated concentrations of nitrites in drinking water is an important health problem, specially by its consequences on infant feeding, in which several circumstances make easy the production of methemoglobinemia. The convenient advised level must be lesser than 25 mg/l and the highest acceptable lesser than 50 mg/l. We decided to study the nitrites contents in drinking water of Zamora, because the absence of current and complete data.
We determined 476 samples of water, collected by plastic containers during winter months of 1992. The nitrite levels were measured by the legal ultraviolet absorption spectrophotometry method (BOE 113811990, 14 sept.) Most of samples (86,4 %) showed acceptable levels of nitrites. We found 23 samples (4,8 %) containing levels above the allowed limits (50 mg/l) and 42 (8,8 %) with increased figures (25-50 mg/l). The mean concentration was 8.07 mg/l in the water of the capital and 12.8 +- 19.44 mg/l in the whole study.
The water supply of towns with high levels od nitrites must be revised, meanwhile its drinking waters are inadvisable for infant feeding.