Ca2+ in your waterNaomi BrynerDavid Millard

Why experiment? Does bottled water have an advantage

to tap water? Is the water company keeping up to

their standards? Has pollution ruined the ecosystem of

our local waterways? What are you putting into your body?

Method Prepared EDTA solution to titrate with

(re-standardized daily), prepared CaCO3 solution to standardize with.

Ammonia buffer was treated to pH 10 daily.

Water samples (10) had pH and temperature recorded on day of testing.

Spike added to show titration method was valid.

DataDay 2

EDTA Concentration 1.017*10-3M Water Fountain

[Ca2+]: 8.069*10-4M, Hardness: 32.34ppm Brockie (untreated)

[Ca2+]: 8.402*10-4M, Hardness: 33.67ppm

Data (Continued)Day 3

EDTA Concentration 1.055*10-7M Acadia bottled water

[Ca2+]: 2.181*10-8 M, Hardness: 8.739*10-4

ppm Aquafina bottled water

[Ca2+]: 1.674*10-9M, Hardness: 6.709*10-5 ppm

Data (Continued)Day 4

EDTA Concentration: 1.182*10-6M Fiji bottled water

[Ca2+]: 1.254*10-6M, Hardness: 5.276*10-2 ppm

Dasani bottled water [Ca2+]:1.620*10-7M, Hardness: 6.493*10-3

ppm

Data (continued)Day 4 (continued)

Tyler Run Creek [Ca2+]: 1.767*10-6M, Hardness: 7.080*10-2

ppm Brockie (treated)

[Ca2+]: 3.854*10-7M, Hardness: 1.544*10-2 ppm

Data (Continued)Day 5

EDTA Concentration: 1.359*10-3M Well water (treated)

[Ca2+]: 1.324*10-3M, Hardness: 53.07 ppm Well water (untreated)

[Ca2+]:1.495*10-3M, Hardness: 59.92 ppm

Sample Source

Har

dn

ess

of

Wa

ter

(pp

m)

1 - W

ell U

2 - W

ell T

3 - B

rock

ie U

4 - B

rock

ie T

5 - c

reek

6 - D

asan

i

7 - F

igi

8 - A

quafin

a

9- F

ountain

10 -

Acadia

-50

0

50

100

150

Figure 1. Mean hardness 95% confidence interval for all samplesCa2+ ppm reports. Sources include (left to right): well water untreated,well water treated, Brockie Commons water untreated, Brockie Commonswater treated, Tyler Run water, Dasani bottled water, Figi bottled water,Aquafina bottled water, Campbell Hall fountain water, and Acadia bottledwater.

Sample Source

Har

dn

ess

of

Wa

ter

(pp

m)

1 - Well U 2 - Well T 3 - Brockie U 9- Fountain0

50

100

150

Figure 2. Mean hardness 95% confidence interval for sampleswith relatively high Ca2+ ppm reports. Sources include (left to right):well water untreated, well water treated, Brockie Commons wateruntreated, and Campbell Hall fountain water.

Sample Source

Har

dn

ess

of

Wa

ter

(pp

m)

4 - B

rock

ie T

5 - c

reek

6 - D

asan

i

7 - F

igi

8 - A

quafin

a

10 -

Acadia

-1.0

-0.5

0.0

0.5

1.0

Figure 3. Mean hardness 95% confidence interval for sampleswith relatively low Ca2+ ppm reports. Sources include (left to right):Brockie Commons treated water, Tyler Run water, Dasani bottlewater, Figi bottled water, Aquafina bottled water, and Acadia bottledwater.

Sample Source Experimental mean

Reported value

tcalc significance

95% CI Relationship to

reported value

1 Well water untreated

59.921 45.7 74.539 ns [60.332, 59.511]

Lower

2 Well water treated

53.072 6.12 125.0485 ns [52.880, 52.264]

Lower

3 Brockie Commons

water untreated

33.672 20.3 7.188 ns [37.674, 29.669]

Lower

4 Brockie Commons

water treated

0.0154 0.6902 11.0433 ns [0.147, -0.116]

Higher

5 Tyler Run water

0.0708 0.02 0.226 * [0.555, -0.414]

Within

6 Dasani bottled water

0.00649 0 0.0371 * [0.384, -0.371]

Within

7 Figi bottled water

0.0503 18 55.202 ns [0.750, -0.649]

Higher

8 Aquafina bottled water

0.000069 0 0.000355 * [0.419, -0.419]

Within

9 Campbell Hall

fountain water

32.340 20.3 62.685 ns [32.753, 31.926]

Lower

10 Acadia bottled water

0.000899 20.3 81.582 ns [0.536, -0.534]

Higher

Discussion Tyler Run, Dasani, and Aquafina had

significantly different concentrations. Difficulties finding known, reliable values. Values were inferred, calculated, or

previously reported. Trace amounts were harder to detect and

report. A spike of 24ppm Ca2+ was added to

verify method.

Discussion (continued) Endpoint of titration, sometimes

questionable. Instrumentation could have helped

proven data. Possible contamination.

Summary Majority of reported values were close to

stated values. Difficulties gathering information on

water samples. Bottled water did have less Ca2+. Treatments for well water and Brockie

water did lower Ca2+ concentration. Thanks to Dr. Foresman for supplying

well water.

References Fiji

www.fijiwater.com/media/newsroom/CA_Water_Quality_Report_June11.pdf

York Water Company www.york water.com/

Well water pubs.usgs.gov/of/2012/1045/pdf/

ofr2012-1045_Reddy_508.pdf

References (continued) Acadia

www.ewg.org/reports/BottledWater/Bottled-Water-Quality-Investigation

Susquehanna River pa.water.usgs.gov/reports/ofr97-

583.pdf Pepsi and Coke

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