Chapter 8, Problem 8.123QA

Interpretation Introduction

To find:

Range for perchlorate concentration in drinking water of $4 to 18\mu g/L$. The perchlorate concentration in stream averages $700.0\mu g/L,$ and the stream flows at an average rate of $161$ million gallons per day ($1 gal = 3.785 L$).

a) What are the formulas of sodium perchlorate and ammonium perchlorate?

b) Calculate the kilograms of perchlorate flow from the Las Vegas stream into Lake Mead each day from the given data.

c) What volume of perchlorate-free lake water would have to mix with the stream water each day to dilute the stream’s perchlorate concentration from $700.0 to 4\mu g/L$?

d) Since 2003, the states of Maryland (MD), Massachusetts (MA), and New Mexico (NM) have limited perchlorate concentrations in drinking water to $0.1\mu g/L$. Five replicate samples were analyzed for perchlorates by laboratories in each state and the following data $(\mu g/L)$ were collected:

MD	MA	NM
1.1	0.90	1.2
1.1	0.95	1.2
1.4	0.92	1.3
1.3	0.90	1.4
0.9	0.93	1.1

Which of the labs produced the most precise analytical results?