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Estimating the concentrations of nitrate and ammonium ions in groundwater
from reclaimed water is extremely important. These determinations are usually
performed in laboratories using sophisticated equipment, and turn-around time can
be from 2 hours to 3 days. Many times, results are needed at the site as quickly as
possible. Alternatively, the rapid determination of both nitrate and ammonium ions
can be estimated using an ammonia field test kit (LaMotte, Chestertown, MD). The
test makes use of the reducing capabilities of titanium chloride (TiCl3), which
converts up to 15 ppm nitrate ion to ammonium ion (Braunstein, et al, 1980).
Nitrate reduced by titanium chloride eliminates the possibility of coming in contact
with poisonous powdered cadmium. Therefore the method is capable of determining
nitrate ion and ammonium ion sequentially using the same ammonia field test kit.
Field test kit concentration estimates of the combined ammonium and nitrate ions
show good correlation with lab results (R2 = 0.85 and 0.89 respectively), and scatter
(standard deviation) between the two methods is small indicating that the test kit is
an acceptable on-site method.
