Rebirth of Water - 2017-2018

all sample were diluted to 1/10 and 1/100, and a 10mL sample was analyzed for all sites except
Spar Cove. The Spar Cove sample was diluted to 1/10, 1/100 and 1/1000 due to increased fecal
counts.
Figure 2.3.C: Image showing the coliform forming units (CFU) per 100 mL water sample taken from
Hazen Creek, site 7.
2.3.7 Ammonia
A blank was prepared by pipetting 50.00 mL of ammonia free water into a 125 mL Erlenmeyer
flask. In the following order, 2 mL of phenol solution, 2 mL of sodium nitroprusside solution, and 5
mL of the oxidizing reagent were added to the flask and immediately covered with parafilm
(samples need to be placed in a dark space immediately after the oxidizing reagent is added to the
flasks). To prepare the samples, 25.00 mL of the water sample was pipetted into a 50 mL
Erlenmeyer flask. Additionally, 1 mL of phenol solution, 1 mL of sodium nitroprusside solution, and
2.5 ml of the oxidizing reagent were then added to the flask, covered with parafilm, and immediately
placed into a dark space. After sitting for at least one hour (maximum of 24 hours), the samples
were then placed in a spectrophotometer and percent transmittance, at 640 nm, was measured
and recorded.
A calibration curve (Appendix B) was constructed to represent the ammonia concentration in mg/L
using the equation found in Appendix A. A stock solution was prepared by dissolving 3.819 g of
dried ammonium chloride in 1000 mL of deionized water volumetrically. This produces 1000 mg/L
of NH 3 N solution. A standard ammonium solution was prepared by diluting 1.00 mL of 1000 mg/L
stock NH 3 N solution into 100 mL of deionized water volumetrically to produce a 10 mg/L NH 3 N
solution. Continuing the serial dilution, 25.00 mL of 10.00 mg/L NH 3 N solution was then diluted in
250 mL of deionized water volumetrically to prepare 1.0 mg/L NH 3 N solution. This diluted standard
solution was pipetted in amounts of 25, 20, 15, 10, 5, 4, 3, 2, and 1 mL into 125 mL Erlenmeyer
flasks and topped up to a final volume of 50 mL. Standards were treated as samples in the above
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