Color is an indication of the amounts of dissolved and suspended materials present in water. Turbid and clear water can be colored. A reasonable color determination can be made by holding a test tube full of the sample against a white background. It is best to let the sample stand for a few minutes to allow the solids to settle. Adjectives such as light, medium and dark can be used to describe the color intensity along with descriptive color names.
Total Suspended Solids (TSS)
Total suspended solids (TSS) gives a measure of the turbidity of the water. We cannot see pH or other kinds of water qualities, but we can observe TSS directly. Suspended solids cause the water to be milky or muddy looking due to the light scattering from very small particles in the water. Sometimes it is mixed with color, but colored waters can also be clear. Normally, we notice suspended solids before we notice anything else. Polluted waters are commonly turbid and improvement is usually marked by greater clarity. Of course, good and useful waters may be turbid, and many clean rivers are never clear because they contain fine suspended minerals that never settle.
To determine total suspended solids, weigh a piece of filter paper as accurately as possible. Filter a one liter sample of water through the weight filter paper. Allow the filter paper to dry completely. Placing a lamp above the filter paper may help the drying process, but take care in not getting the filter paper too hot.
Reweigh the filter paper. The change in weight is the weight of the total suspended solids. TSS values are commonly expressed in ppm (mg solids per liter of water).
Total Dissolved Solids (TDS)
Measures of the nutrient material dissolved in the water are indicators of productivity. High total suspended solids usually indicate fertile and producing waters. The experiment testing for the Total Dissolved Solids (TDS) is rather simple, but requires exact measurements. Using an analytical balance that weighs to the 0.0001 g is desirable.
Weight to the nearest 0.0001 g, if possible, 3 clean dry 250 ml beakers or evaporating dishes. Pour 100.0 ml of the filtrate from the TSS experiment (See Total Suspended Solids) in each of the containers. Slowly and carefully evaporate the water sample to dryness, using a hot plate. Do not let the samples get too hot or some of the dissolved solids may be vaporized or decomposed.
When the samples are dry, reweigh the containers and determine the weight of the solids dissolved in 100 ml of water. Average the 3 values. Convert the result to ppm by multiplying the value obtained by 10,000.
Color is an indication of the amounts of dissolved and suspended materials present in water. Total suspended solids (TSS) gives a measure of the turbidity of the water. Total dissolved solids gives a measure of the nutrient material dissolved in the water are indicators of productivity.