Q and A_Water Quality Analysis.pdf

Questions and Answers

Solicitation 12405B23Q0052

Water Quality Analysis

March 20, 2023

1. Table 1 in the Statement of Work references three specific instruments.

a) For total and soluble reactive phosphorus, nitrate-nitrogen and total nitrogen, would it be acceptable to use automated segmented flow instrumentation (SEAL AA500) instead of a continuous flow system such as the referenced Skalar San ++ Wet Chemistry System?

A. Yes, as long as the inorganic P and N forms are being measured.

b) Would it be acceptable to use a Milton Roy spectrophotometer instead of a Beckman

Spectrophotometer for nitrite analysis?

A. Yes, as long as the calibration curve follows linear pattern with R2 of >0.96.

2. Table 1 in the Statement of Work references a handful of methods. It's not clear if APHA 4500 at the bottom of the Method column refers only to nitrite or if any of the series of APHA 4500 methods are acceptable for any of the desired analytes. Would the following methods be acceptable?

• Nitrate-nitrogen: 4500-NO3 F (rough equivalent of 353.2)

• Total phosphorus digestion: persulfate digestion using 4500-P B 5 (rough equivalent of procedure in

365.1)

• Total phosphorus analysis: 4500-P F (rough equivalent of 365.1)

• Total Nitrogen: persulfate digestion using 4500-N C (rough equivalent to 4500-P J) followed by analysis using 4500-NO3 F

A. Yes, these methods analyze inorganic forms of N and P in the water samples.

3. The statement of work states that data must be reviewed and approved by a PhD level Scientist. Are equivalencies acceptable? For instance, would it be acceptable for a Bachelor level scientist, with 29 years of experience performing/supervising analytical chemistry in an accredited laboratory, to review and approve data?

A. Yes.

4. In sections 5.5 and 5.6 of the Statement of Work the phrase "no less than" is used. Should it say, "no greater than"?

A. The phrase should be “no greater than”.

5. In the Statement of Work Section 5 Delivery/Schedule – it says that samples will be frozen and shipped every two weeks.

Although in the SOW Section 2 Table 1 the holding time for nitrite is 48 hours.

A. The holding time is for samples that are not pre-treated with acid, however, the samples that we will be sending to the service laboratory every two weeks will be pre-treated with sulfuric acid to bring down the pH to 2.