AWWA WQTC65748

Nitrates are particularly harmful to human health because of the reduction to nitrite which takes place in humans. Long term effects arise from reaction of nitrites with certain substrates such as amines, amides, and amino acids to produce N-nitroso compounds, which have been found in numerous animal studies to be carcinogenic. Due to this factor, nitrate and nitrite are regulated by the US Environmental Protection Agency (USEPA) (maximum allowable levels are 10ppm and 1ppm, respectively) due to their common occurrence as constituents in drinking water. The analysis of these compounds is a routine analytical procedure in most water laboratories. The standard method for the determination of nitrate in drinking water, USEPA Method 353.2 "Determination of Nitrate-Nitrite by Automated Colorimetry," employs cadmium as the reductant for the conversion of nitrate to nitrite. The nitrite is then analyzed colorimetrically by way of the Griess reaction. This procedure is not only tedious, but the byproducts of the cadmium column are hazardous to the environment. Once cadmium is introduced to the soil, plants uptake the cadmium, and then, via the food chain, the exposure is passed upward towards humans. The objective is to find an alternative by use of Superior Stock Nitrate Reductase or YNaR1 (The Nitrate Elimination Co. of Lake Linden, Michigan). This enzyme, a natural reductant, combined with NADH, can replace the cadmium column reduction, thus eliminating the need to dispose of toxic cadmium waste. Includes 3 references, table, figures.