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ClemensKen Lake

Ken Lake Water Analysis

Envronmental Analysis, 2002-03

Jon Clemens, Alan Arvidson, Heather Rankin, and Jeff Taisch

Jon Clemens, Individual Report, 11/14/02

Introduction

Ken lake is located in NW Olympia, WA and is surrounded by the Lakemoor residential development located just south of the Black Lake exit of Hwy 101. It coveres a total area of over 1,000,000 square feet, and is about 6000 feet in perimeter. The average depth of the lake is about 2.2 meters, measured over a period of five weeks. It is used for recreation and has a large housing development along the shore. Formerly known as Simmons Lake, it receives runoff from the surrounding yards and also receives biocide treatments for vegetation control. These factors will greatly contribute to the future direction of our analyses. There are floating docks at several locations on the lake. We have hypothesized that certain chemicals from dock treatment products will show up in further research. Research is continuing in these areas. Motor boats are not allowed on the lake but there are canoes, rowboats and paddleboats that are frequently used for recreational purposes.

We are currently undertaking a chemical analysis of the lake water samples. As of the present time, analyses have been done for the following: NO2-, NO3-, Cl-, SO4-, PO4-, Na, and K. The alkalinity of the lake has also been monitored throughout our investigatoin. In addition the these laboratory tests, several physical parameters of the lake were measured while in the field. These include temperature, dissolved oxygen, conductance, pH, visibility, and salinity. Certain characteristics of the lake have naturally undergone changes during the course of our investigation and we expect these same characteristics to remain unsettled in the future. For instance, the temperature has dropped from an average of 16.2 C on 10/04/2002 to an average of 8.9 C on 11/08/2002. Mapping these changes in the lake composition is a major goal of our long term research.

Materials and Methods

During our sampling of lake water, we used a two-man plastic paddleboat to navigate to the sampling sites. A secci disk was used for the visibility and depth measurements and averages of these were taken across the lake. The Van Dorm water sampling apparatus was used to take water samples from the various depths and transfer them into the sample bottles. An 85D YSI meter measured the physical parameters of temperature, dissolved oxygen, salinity, and conductance at 1 meter intervals. The Oakton pH meter (model 35613) was used to determine an average pH for our lake since no hypolimnion or epilimnion existed (the lake was holomictic). The samples were collected and prepared for chemical analysis by the methods listed below in the AA section. A Garman eTrex Summit GPS unit was used to mark are coordinates at the sample sites. Vertical profiles of these parameters were produced using the graphing feature of Microsoft Excel.

Alkalinity titrations were carried out by titrating the water samples with 0.01601 M HCl to a pH of 4.50. The pH was monitored with the pH meter, and the alkalinity was expressed in terms of mg/L CaCO3. We used a micropipette device to deliver the HCl in order to get more precise results.

The ion chromatograph was used to analyze for NO2-, NO3-, Cl-, SO4-, and PO4-. Standards were prepared at 10, 1, and 0.25 mg/L concentrations of Cl-, NO2-, and NO3- and 40, 4, and 1 mg/L concentrations of SO4- and PO4-. Logger Pro software was used to integrate the voltage peaks for the anions in the column. Linear Regression analysis was used to determine the concentrations of analytes in our samples. Ion chromatograph results were obtained by Jeff Taisch and are included in the group report.

Results

The vertical profiles can be seen in the following series of graphs in figure 1. The average secci disk reading for Ken Lake was 2.2 m. The disk was visible to the lake bottom at all locations. The average pH of the lake was 6.50 according to the samples obtained at various depths and locations using the Van Dorm bottles. The average alkalinity for Ken Lake water was 8.529 mg/L CaCO3 on 10/25/02 and 10.238 mg/L CaCO3 on 11/08/02. Our data set can be viewed on Workspace on Masu in the PRG_EA/Projects/Ken Lake folder.

Discussion

It was interesting to note that the alkalinity of Ken Lake seemed to drop from 10/25 to 11/08. There are a couple of factors that could have contributed to this. First, it is possible that the lake was undergoing a change in compisition during this time. However, care shouild be taken in the future to always carry out the titrations as soon as possible. The water samples taken on 10/25 were not titrated on the day they were collected, while the ones collected on 11/08 were. In the future, all alkalinity titrations will be carried out on the same day that they were collected.

There is no eveidence of a chemocline on Ken Lake, nor of an epi- or hypo- limnion according to the depth profiles. However, there is a small increase in conductance and temperature at the bottom of the lake. Reasons for this could be organic activity at the lake bottom or sediment contact with the YSI electrode. For this reason, averaging our results for pH, temperature and other physical parameters was justified for a description of the lake as a whole.

Our future research is going to include further analysis of the methods explained in the group report, which include anion and cation concentration analyses and alkalinity titrations as well as monitoring physical parameters. We will branch out into searching for possible pollutants originating from wood treatment products and biocide residue byproducts. A more developed profile of Ken Lake can be generated once more data is obtained.

Analysis of Ken Lake Water for Sodium and Potassium Using Atomic Absorption Spectroscopy

Abstract

The atomic absorption spectrometer can be used to analyze water samples for specific elements. In particular, we were interested in concentrations of Na and K present in water from Ken Lake in Olympia, WA. Sodium was found to be present in concentrations of 3.0 ppm and potassium was found to exist in concentrations of 1.2 ppm.

Introduction

Currently, we have been unable to find documentation of past analyses of Ken Lake for Na and K. However, we have found data of Thurston County well water and have identified 3 wells within 1500 meters of the lake. Typical Thurston County groundwater has Na concentrations of 6.5 mg/L and typical K concentrations are 1.6 mg/L (according to median of 359 wells). The three wells located within 1500 m of Ken Lake showed an average Na concentration of 4.6 mg/L and an average K concentration of 2.5 mg/L. We sought to make determinations of the concentrations of these elements in the lake water itself.

Materials and Methods

Sample Preparation

Samples of lake water were taken from Ken Lake, Olympia, WA on 11/08/02 from the coordinates 47 01’ 59.1” N latitude, 122 57’ 04.6” W longitude. The samples were taken from 0.5, 1.5, and 2.1 m depth and labeled A, B, and C, respectively. They were contained in one-liter, Nalgene bottles for a few hours until filtered with a 0.45 μm membrane filter with a vacuum filter apparatus. About 250 mL of the filtered samples were placed into acid-washed 500 mL Nalgene bottles and treated with enough HNO3 to lower the pH of the water to < 2.00. An additional 125 mL was put into clean Nalgene bottles for ion chromatograph analysis. The rest of the samples were used for alkalinity titrations. Samples were placed in refridgerator until analyzed.

Stock solution of NaCl and KCl were prepared by the faculty:

Na Standard:1000 μg/mL1.2707 g NaCl / 500 mL

K Standard:1002 μg/mL1.9025 g KCl / 1000 mL

The total concentration of Na in the solution is then 1g/mL (1 ppm). The total concentration of K in the solution is then 2 g/mL (2 ppm). We also added 10.00 mL of a CsCl solution at 10,000 ppm as a source of easily ionized electrons. The solution was transferred to plastic bottles for use in the AA instrument.

A medium standard was prepared with concentrations of 3 µg Na/mL and 6 µg K/mL. This corresponds to 3 and 6 ppm.

For the preparation of a blank, 10.00 mL of 10,000 ppm CsCl solution was diluted to 100.00 mL.

The full procedure for use of the AA instrument can be found on our website (see bibliography for web address). The instrument parameters used during this analysis are detailed in Table-4. The AA instrument was used for a total of 67 trials including our blanks and instrument-drift checks. The standard methods handbook cites a linear working range for concentrations of Na of up to 1 μg/mL and up to 2 μg/mL for K. Blanks were run at the beginning, middle and end of our trials to correct for background and drift check. The instrument showed little to no drift throughout the analysis.

Regression analysis was used to determine the concentration of both Na and K. Since both averages fell within the linear working range, this was a simple task and the equation that we used was as follows:

C = A/k

where C is the concentration of the sample, A is the measured absorbance and k is a constant specific to the element. The constant, k was obtained through the regression analysis. Its values are: for sodium, k = 0.1970; for potassium, k = 0.2235. Regression analysis was carried out with Microsoft Excel, version 9.0.4402.

Table 1 Showing the parameters of the Perkin Elmer atomic absoption spectrometer

Perkin Elmer Atomic Absorption Spectrometer
Na / K
Slit Width / 0.7 nm / 1.4 nm
Wavelenth / 589 nm / 766.5 nm
Lamp Current / 10 mA / 12 mA
Slit Setting / 3 / 4
Wavelength Setting / VIS-295 / VIS-383

Results

We showed an average Na concentration of 3.0 ppm (3.0 g/mL) and an average K concentration of 1.2 ppm (1.2 g/mL) for our samples. Sample A from 11/08/02 showed values of Na and K concentrations much higher than the rest of the samples (greater than 2 standard deviation values form the mean, and can be thrown out with greater than 90% confidence according to the statistical Q-Test for bad data). Therefore, they were not considered in the final analysis of data. Table 2 summarizes the results from our trials run on the atomic absorption spectrometer.

Table 2 Results from our atomic absorption spectrometer analysis of Ken Lake water

Potassium / Sodium
Absorbance / Absorbance
mean K blank / 0.008 / mean Na blank / 0.069
mean K conc / 0.034 / mean Na conc / 0.127
corrected / 0.026 / Corrected / 0.058
mean low std / 0.455 / mean low std / 0.265
corrected low std / 0.447 / corrected low std / 0.197
Regress Anal Info / Regress Anal Info
conc / abs / conc / Abs
0.000 / 0.000 / 0.000 / 0.000
2.000 / 0.447 / 1.000 / 0.197
Total avg K (ppm) / 1.2 / Total avg Na (ppm) / 3.0

Discussion

The sample of water contained in sample bottle A showed unusual results in tests for sodium and potassium during this trial. In addition to atomic absorption spectroscopy, the ion chromatograph was used to analyze Ken Lake water for sulfates, among other anions. Those results showed unusually high concentrations of sulfates in the water. Additionally, the acetic acid method for determination of dissolved, reactive phosphporus showed absorbance more than 2 times higher than absorbances in the other two lake samples taken on the same day.

References

Department of Ecology, “For Temporary Modification of the State Surface Water

Quality Standards for the Use of Pesticides to Control Aquatic Pests Plants and/or Algae in Ken Lake.” Administrative Order No. DE 01 WQSR-2468. July 2001. Document stating specific conditions for herbicides applied to Ken Lake, chemical requirements, general conditions, and public notices. Requested and received from Kelly Susewind, Southwest Region Manager, Water Quality Program, DOE.

Drost, B.W., Turney, G.L., Dion, N.P., and Jones, M.A. Hydrology and Quality of Ground Water in Northern Thurston County, Washington. Tacoma, Washington. 1998. Water-Resources Investigations Report 92-4109 (Revised). Describes groundwater system in Thurston County, WA, discusses chemical characteristicsof water in aquifers and patterns of groundwater contamination and establishes guidelines for monitoring of groundwater levels and quality. Complete with charts and tables. From U.S. Department of the Interior and U.S. Geological Survey.

Lebow, Stan T., Lebow, Patricia K., Foster, Daniel O. “Environmental Impact of Preservative Treated Wood in a Wetland Boardwalk.” Forest Products Laboratory. February 2000. Discusses different chemicals used for wood treatments on hard to treat woods and how these treatments react in environments with heavy rainfall. Specific mentions of environmental concerns with treatments used in the North West, mostly copper, zinc, and arsenic metals leaching out. Authors consist of a Research Technologist, a Mathematical Statician, and

Lebow, Stan T., Halverson, Steven A., Morrell, Jeffrey J., and Simonsen, John. “Role of Construction Debris in Release of Copper, Chromium, and Arsenic From Treated Wood Structures.” Forest Products Laboratory. June 2000. Provides information on different wood preservatives from treated woods in manufacturing. Includes leaching, chemical treatments, and different types of woods. Discusses the risks of chromated copper arsenate as wood treatment. Authors all work for Forest Products Laboratory, Madison, Wisconsin.

McCord, James T., Moore, Barry C., and Searcy, Chris C. “Hydrological and

Limnological Study of Ken Lake, Washington.” State of Washington Research Center.November 1989. Washington State University-Pullman. General report of formation and overview of Ken Lake system, i.e. phosphorous levels, topography, infiltration capacity, etc., and the Lakemoor community’s effects on the lake, including problems with runoff, storm water drainage, and sewer leakage. Most comprehensive report found on Ken Lake.

Online: < (Accessed 11/13/02). CAS # 145733

and CAS # 1071836. Gives comprehensive information on chemicals, including EPA methods for chemical applications, melting points and decomposition, sensitivity data, and environmental impact. Analytical chemistry web site, nationally known.

Standard Methods Handbook for the Atomic Absorption Spectrometer. Located at The Evergreen State College, Lab 1, 2nd floor, in the Environmental Lab. Commonly referred to as the “Bible,” the handbook gives specifics for wavelength settings for different cathode lamps, flame settings, slit widths, and many other useful pieces of information on properly operating the Atomic Absorption Spectrometer for different elements.

Stroh, J. “Operating Instructions for the Atomic Absorption Flame Unit.” 1988 (modified 1999). Instructional paper provided by The Evergreen State College. Provides information on proper operation of the Atomic Absorption Spectrometer. Author is currently a Professor of Geology/Hydrology at The Evergreen State College in Olympia, Washington and is also currently undergoing an in-depth research project in the Saline Valley, California.