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Exercise 8
a 50-ml sample are used,
meq/I = (0.4) x (ml acid used)
Since the equivalent of CaC03 is 50, the meq/I can be derived by dividing mg/l by 50.
When alkalinity is expressed in milliequivalents per liter, it is an entirely unambiguous
quantity that will not be altered by the addition of CO 2 , which results in conversion of
carbonate to bicarbonate.
3. Calculate the total inorganic carbon (DIC) theoretically available for photosynthetic
utilization (See Fig. 8.5).
4. Collect water from the littoral zone among dense stands of submersed macrophytes and
make similar measurements.
5. Collect water from inlet sources (inlet stream, springs) and from the outlet, and make similar
measurements.
6. Answer the questions following Option 2 using your data.
OPTION 2. LABORATORY EXERCISES
1. Measure the pH of tap water and of samples of natural water provided by your instructor.
Determine the pH of the water samples electrometrically and compare to estimates using pH
indicator papers (see Option I, Sect. I).
2. Measure the phenolphthalein and total alkalinity (see methods of Option I, Sec. 2) of the
following samples:
a. Tap water, full strength and serially diluted with distilled water to concentrations
< 15mg/1.
b. Lake or stream water provided.
c. Analyze three samples using bromcresol green-methyl red mixed indicator and compute
the standard deviation (see Appendix 2).
d. Compare the above results to those of a sample analyzed using methyl orange indicator.
Try this comparison on dilute samples.
3. Measure the alkalinity by Gran titration analysis (see Option 1, Section 2a). Interpret your
results analogous to those illustrated in Fig. 8.3 and compare the results of this method with
those obtained with color indicator solutions.
4. Using your data or those given in Table 8.3 and 8.4 answer the following questions.
Questions
1. Compare graphically the vertical profiles of the following parameters from your lake system
(Option 1) or from the data given in Table 8.4 or Table 8.5 (Option 2):
a. Total alkalinity.
b. Temperature.
c. pH values.
d. CO2 concentrations.
e. Inorganic carbon (DIC) available for photosynthesis.
f. Hardness equivalents.
2. From the collection of data from vertical profiles made in your lake at two or more intervals
separated by at least a month (Option 1) or from data given in Table 8.4 or Table 8.5
(Option 2), calculate the changes in the various parameters evaluated. Discuss the potential
causes of the losses from and gains to the strata. What are the potential effects of such seasonal
changes on the distribution and availability of other ions and compounds on the biota?
3. Compare the horizontal variations of the concentrations of the measured parameters
(Question 1) found in the littoral zone, inlet sources, and the outlet to those observed in the
surface waters of the central station. Discuss the potential causes of the differences.
Exercise 8
a 50-ml sample are used,
meq/I = (0.4) x (ml acid used)
Since the equivalent of CaC03 is 50, the meq/I can be derived by dividing mg/l by 50.
When alkalinity is expressed in milliequivalents per liter, it is an entirely unambiguous
quantity that will not be altered by the addition of CO 2 , which results in conversion of
carbonate to bicarbonate.
3. Calculate the total inorganic carbon (DIC) theoretically available for photosynthetic
utilization (See Fig. 8.5).
4. Collect water from the littoral zone among dense stands of submersed macrophytes and
make similar measurements.
5. Collect water from inlet sources (inlet stream, springs) and from the outlet, and make similar
measurements.
6. Answer the questions following Option 2 using your data.
OPTION 2. LABORATORY EXERCISES
1. Measure the pH of tap water and of samples of natural water provided by your instructor.
Determine the pH of the water samples electrometrically and compare to estimates using pH
indicator papers (see Option I, Sect. I).
2. Measure the phenolphthalein and total alkalinity (see methods of Option I, Sec. 2) of the
following samples:
a. Tap water, full strength and serially diluted with distilled water to concentrations
< 15mg/1.
b. Lake or stream water provided.
c. Analyze three samples using bromcresol green-methyl red mixed indicator and compute
the standard deviation (see Appendix 2).
d. Compare the above results to those of a sample analyzed using methyl orange indicator.
Try this comparison on dilute samples.
3. Measure the alkalinity by Gran titration analysis (see Option 1, Section 2a). Interpret your
results analogous to those illustrated in Fig. 8.3 and compare the results of this method with
those obtained with color indicator solutions.
4. Using your data or those given in Table 8.3 and 8.4 answer the following questions.
Questions
1. Compare graphically the vertical profiles of the following parameters from your lake system
(Option 1) or from the data given in Table 8.4 or Table 8.5 (Option 2):
a. Total alkalinity.
b. Temperature.
c. pH values.
d. CO2 concentrations.
e. Inorganic carbon (DIC) available for photosynthesis.
f. Hardness equivalents.
2. From the collection of data from vertical profiles made in your lake at two or more intervals
separated by at least a month (Option 1) or from data given in Table 8.4 or Table 8.5
(Option 2), calculate the changes in the various parameters evaluated. Discuss the potential
causes of the losses from and gains to the strata. What are the potential effects of such seasonal
changes on the distribution and availability of other ions and compounds on the biota?
3. Compare the horizontal variations of the concentrations of the measured parameters
(Question 1) found in the littoral zone, inlet sources, and the outlet to those observed in the
surface waters of the central station. Discuss the potential causes of the differences.