Wednesday, January 5, 2011

WATERS Chemistry doin' water chemistry

AC Davis Chemistry students were able to participate in a half day fieldtrip in September to visit the Yakima Sewage Treatment Plant and the Yakima River. It was a great opportunity learn how Yakima's waste water gets "cleaned up" and a chance to measure Yakima River water quality parameters at right near the river's edge.

Yakima River Water Quality

Students were able to test water samples for several important water quality parameters including temperature, pH, conductivity, hardness, and dissolved oxygen. Each of these variables can provide a measurable way to assess river health, both for humans and other living organisms.

Water temperature is a very important water quality parameter, because it can affect both the water chemistry as well as the function and variety of aquatic life in the system.

Did you know that the term pH comes from the French "puissance d'Hydrogene" which means the strength of the hydrogen? Optimum pH for river water is near neutral and extremes in pH can have devastating effects on aquatic life!

Another water chemistry parameter you might not be familiar with is water hardness. Hardness is a measure of the amount of calcium and magnesium ions dissolved in water. In the Yakima watershed water hardness is mainly due to deposits of calcite in the basalt formations and is reported as parts-per-million (ppm) Ca2+.

Conductivity is a measure of how well water can pass an electrical current, thus it is an indirect measurement of the many different dissolved solids in the water. In the Yakima watershed the concentrations of these dissolved solids are affected by the bedrock (containing calcite), agriculture (fertilizers), and road runoff. Decreases in conductivity can indicate the presence of organic pollutants.

Students were also able to make observations about the river, including water color, height, and riverbank vegetation.

Yakima Wastewater Treatment Plant Tour

Students also had the opportunity to learn about the inner workings of the Yakima Wastewater treatment plant.

Many thanks to all the fieldtrip helpers and treatment plant for hosting this great trip!

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