Nitrate in drinking water in the West German wine-growing areas of Baden and Württemberg.

Abstract

Nitrate is regarded as a substance whose presence in drinking water is not considered as desirable. If reduced to nitrite it may cause methomoglobinemia in infants. Onward reaction with amines capable of coupling will result in the formatin of nitrosamins. Excessive use of fertilizers in agriculture is the most frequent cause of elevated nitrate contents of drinking water. To quantify this problem, drinking water was sampled at taps at 200 sites arranged on a grid covering the wine-growing areas of Baden and Württember. These samples were examined for their content of nitrate, chloride, and sulphate by means of ion chromatography. Clearly elevated nitrate contents were revealed by the resuls of measurements: 13% of samples showed values above the maximal concentration admissible under the EC Drinking Water Directive of 50 mg NO-3/l and 42% above the EC guide level. The excessive levels were mostly found in the regions of Kaiserstuhl-Tuniberg-Markgräflerland and Württembergisch Unterland. Many samples with an elevated nitrateacontent exhibited also elevated sulphate contents. The high nitrate levels are attributed to the use of nitrogen fertilizers in the vineyards.