LaMotte AM-21 Water Pollution Detection Outfit - Manual (Page 43)

Sulfide Test
Sulfide occurs in many well water supplies and sometimes is formed in lakes
or surface waters. In distribution systems it may be formed as a result of
bacterial action on organic matter under anaerobic conditions. It may also be
found in waters receiving sewage or industrial wastes. Concentrations of a
few hundredths of a milligram per liter cause a noticeable odor. Removal of
sulfide odor is accomplished by aeration or chlorination. Hydrogen sulfide is
a toxic substance acting as a respiratory depressant in both humans and fish.
Hydrogen sulfide or soluble sulfides are detected by treating the sample with
para-aminodimethylaniline and ferric chloride in acid solution to form the
well known dye Methylene Blue. The reaction is sensitive to very small
traces of sulfide and can be applied to the determination of hydrogen sulfide
in air.
NOTE: The sample should be collected with a minimum of aeration and
should be analyzed promptly. *Sulfide Reagent A (4458) is a strong
acid solution and should be handled with great care.
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