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Master Naturalists: What's in the Guadalupe's water? Part 2: Testing water quality

By Paul and Mary Meredith
Jan. 4, 2011 at midnight
Updated Jan. 5, 2011 at 7:06 p.m.

Texas Stream Team volunteers use a bucket to take a water sample and then use this test kit for analyzing the sample to check water quality in our rivers.  The disk at the top goes into the water to test water cloudiness (turbidity).  The thermometer on the left measures air and water temperature, and the meter on the right tests pH.  The vials and bottles of chemicals are used for water chemistry to determine the sample's Total Dissolved Solids, and Dissolved Oxygen.  Another kit (not shown) and a chicken egg incubator are used to culture for Coliform bacteria in a sample.

Editor's Note: This is the Part II of a series taking a look at the Texas Stream Team.

By Paul and Mary MeredithTexas Stream Team volunteers collect and analyze water quality data for Texas's inland waterways. Collecting water quality data requires, first, TST volunteers complete a rigorous eight-hour training program for certification to collect representative water samples, and observe and report such field observations as air and water temperature, weather conditions, and water color. They also make other field observations, and measure/analyze several inorganic and organic water characteristics. We'll discuss some TST tests.


Water temperature's measured because it influences several water quality aspects, for example, feeding, reproduction and metabolism of aquatic life. Volunteers measure pH, total dissolved solids (TDS), dissolved oxygen (DO), and turbidity. They measure turbidity (water's "muddiness") with a Secchi disk.

The pH level indicates water's acidity or alkalinity on a 0-14 scale. When the pH level falls outside the normal (5-9) range, its acidity or alkalinity becomes a problem for aquatic life. Second, specific conductivity (SC), a measure of TDS, is evaluated. Dissolved solids can be inorganic substances, like sodium chloride (salt); or organic ones, like nitrates and phosphates (both fertilizers). Generally, higher SC values indicate salty or polluted water; lower values, fresh water. A sample is also tested for dissolved oxygen (DO). Dissolved oxygen is oxygen freely available for fish and other aquatic life. Traditionally, DO level has been accepted as the single most important indicator of a body of water's ability to support desirable aquatic life.


Animal waste, untreated sewage or human waste in water create problems. Besides collecting data like stream flow rate, turbidity, when it last rained, etc., volunteers measure whether E. coli's present. E. coli's the Coliform bacteria easiest to measure, and it's indicative of other Coliform bacteria's presence in water. To measure E. coli, volunteers prepare a culture in a Petri dish using sample water and a sterile bacteria nutrient. They incubate the culture 28 hours, and then count the bacteria colonies found to indicate the degree that organic pollution is present.


After volunteers finish monthly water sampling, they send their results to Texas State University. Data stored there is available for use by TCEQ, EPA, water authorities like GBRA, and the public, for study, analysis and/or making decisions.


Members of Texas Master Naturalist chapters have been certified as TST volunteers, to sample and analyze watersheds in their areas. Students in University science program(s); elementary, middle and high school students have been trained and use TST participation as a real-world application of methods and procedures learned in classes, while doing a service important to all Texans. Companies and municipal groups participate in TST also. Interested individuals, groups, schools or companies wanting to help should contact TST's Statewide Monitoring Coordinator; Josh Oyer at oyer@txstate.edu. Information can also be requested online at http://txstreamteam.rivers.txstate.edu/About-Us/info.html.

Paul and Mary Meredith are master naturalists. Contact them at paulmary0211@sbcglobal.net.



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