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Sooke River Twelve Month Baseline Water Quality Study for Salmonids
by Judith R. Burke
Waterose Environmental Services
Vancouver Island, BC
3. Methods
3.1 Methods
The methods are based on a combination of factors, which include the desired objectives, technical experience, cost, and, time. The study involved over 150 sample days; therefore, affordable methods are an integral factor when selecting methods. The primary instruments include a colorimeter, digital titrator, and an electrochemical multi-meter. The study occurred from September 22, 1999 to September 21, 2000.
3.2 Quality Control and Quality Assurance
The high volume of sample days and frequency of tests limited the extent of a rigorous Quality Control and Quality Assurance program. This is one of the limitations of this study. Furthermore, because there were no previous test results for this area, the standard deviations were not available to pre-determine minimum sampling requirements. Therefore, it was determined that a minimum sample number of 12 were required for each test for each season for each site.
Ideally, one would implement a rigorous field program with field-split samples, duplicate samples, spiked samples, and an additional control site and external laboratory analysis; all of which would have rendered the project economically unfeasible. The compromise was to implement affordable methods, which were within the control of the project and still obtain quantified results. These include consistent methods, dedicated glassware and tools for each test, pretreated containers, triplicate rinsing with triple distilled de-ionized water and sample water, constant temperature control, laboratory water for reagent blanks, and extreme diligence and care.
3.3 Sample Collection
The water samples were collected clean glass or plastic containers, which were pretreated as required by the manufacturers specifications depending on the parameter tested. Different pre-treatments included acid rinse with hydrochloric acid, nitric acid, and/or industrial bleach solution. The samples were obtained in-stream in laminar flow below a point of mixing such as a waterfall or a stream riffle. The samples were tested immediately at streamside for half of the parameters. A second set of fresh samples were obtained and tested immediately off site for the balance of the parameters, which required more complex sample preparation for the test procedure. Every reasonable attempt was made to maintain the temporal spacing of sample collection.
3.4 Instrumentation
The selection of instruments was based on three factors: cost, operator knowledge, and instrument performance. The budget was limited to $5,000 for the purchase of instruments.
The primary objective was to obtain quantified test results. There are alternate instruments available to test water chemistry; however, the limiting factor is primarily the cost associated with using high performance laboratory analytical equipment. The primary instruments included a colorimeter, digital titrator, and, an electrochemical multi-meter.
3.4.1 Colorimeter
The colorimetric analysis was completed using a colorimeter. The basic principle of analysis is to mix a known quantity of chemical reagent with an unknown quantity of the species of interest. The product of the reaction changes colour and the colour intensity is proportional to the concentration of the species of interest. The colour intensity is measured by a light beam with a known frequency directed through the reaction chamber to a photovoltaic receptor cell. The amount of light that does not pass through the sample is measured as light absorbed. The absorbance reading is related to known absorbance for known quantities of the species of interest in different solution concentrations, which are precalibrated into the instrument. The relative absorbance is plotted against the known slope of known concentrations and the concentration of the sample is interpolated from the slope of the line. For some parameters, there is a direct mathematical relationship between a specific species and an alternate form of the same species. The readings are stored into the memory of the colorimeter and downloaded daily for statistical analysis at the conclusion of the season.
The ranges and estimated detection limits vary depending on the selected test. The specific colorimetric tests completed for this study are described in Table 13.
Table 13. Colorimetric Analysis Parameters, Ranges, and EDL's.
|
Parameter |
Primary |
Alternates |
Range |
EDL |
|
Aluminum |
Al |
Al Al2O3 |
0 to 0.80 mg/L Al |
0.013 mg/L Al |
|
Bromine |
Br2 |
Br2 |
0 to 4.50 mg/L Br2 |
0.04 mg/L Br2 |
|
Chlorine, Total |
Cl2 |
Cl2 |
0 to 2.00 mg/L Cl2 |
0.02 mg/L Cl2 |
|
Chromium, Hexavalent |
Cr6+ |
Cr6+ CrO4 Cr2O7 |
0 to 0.60 mg/L Cr6+ |
0.01 mg/L Cr6+ |
|
Copper, Low Range |
Cu |
Cu |
0-210 �g/L |
5.4 �g/L Cu |
|
Fluoride |
F |
F |
0 to 2.00 mg/L F- |
0.05 mg/L F- |
|
Iron, Ferrous |
Fe |
Fe |
0 to 3.00 mg/L Fe |
0.03 mg/L Fe |
|
Manganese |
Mn |
Mn MnO4 KMnO4 |
0 to 0.700 mg/L Mn |
0.007 mg/L Mn |
|
Molybdenum Molybdate, Low Range |
Mo6+ |
Mo6 MoO4 |
0 to 3.00 mg/L Mo6+ |
0.07 mg/L Mo6 |
|
Nickel |
Ni |
Ni |
0 to 1.000 mg/L Ni |
0.013 mg/L Ni |
|
Nitrate, Low Range |
NO3--N |
NO3-N NO3 |
0 to 0.50 mg/L NO3-N |
0.01 mg/L NO3--N |
|
Nitrite, Low Range |
NO2- |
NO2- NO2- - N NaNO2- |
0 to 0.350 mg/L NO2- N |
0.005 mg/L NO2N |
|
Nitrogen Ammonia |
NH3-N |
NH3-N NH3 NH4 |
0 to 0.50 mg/L NH3-N |
0.02 mg/L NH3-N |
|
Phosphorus |
PO43- |
� |
0-2.50 mg/L PO43- |
0.05 mg/L PO43- |
|
Silica, High Range |
Si |
SiO2 Si |
0 to 75.00 mg/L SiO2 |
1.00 mg/L SiO2 |
|
Sulphate |
SO4 - |
SO4 - |
0 to 70 mg/L SO4 - |
4.9 mg/L SO4 - |
|
Sulphide |
S2- |
S2- |
0 to 0.70 mg/L S2- |
0.01 mg/L S2- |
|
Tannin & Lignin |
Tannic |
Tannic |
0 to 9.0 mg/L tannic |
0.1 mg/L tannin & lignin |
|
Turbidity |
� | � |
0-1000 FAU |
21 FAU |
|
Zinc |
Zn |
Zn |
0 to 3.00 mg/L Zn |
0.02 mg/L Zn |
3.4.2 Digital Titrator
The titration analysis was completed using a digital titrator. The basic principle of analysis is to add a known titrant to the water sample. The product of the reaction changes colour and the concentration is determined by relating the quantity of titrant relative to the volume of the water sample. The specific titrations completed for this study are described in Table 14.
Table 14. Description of Titration Analysis Parameters, Ranges, and, EDL's.
|
Parameter |
Range |
EDL |
|
Carbon Dioxide CO2 |
20 to 100 mg/L |
+/- 1% |
|
Hardness, as Calcium Carbonate CaCO3 |
10 to 40 |
+/- 1% |
3.4.3 Electrochemical Probe
The electrochemical analysis was completed using an electrochemical multi-meter with three probes to measure dissolved oxygen, conductivity, and pH. The EDL's of the probes are: dissolved oxygen +/- 1%, dissolved oxygen +/- 0.1 mg/L, conductivity +/- 1�s, total dissolved solids +/- 1 mg/L, and, pH +/- 0.01 pH units.
The probe was calibrated before each field trip in manufacturer calibration solutions. Duplicate meters with stable triplicate readings were used to obtain the data.
Next Section 4. Results
Return to Table of Contents
For more information about the Sooke River Watershed:
Email Judith Burke at Waterose Environmental Services
Other Water Quality Projects by Waterose:
Water Quality Tests Offered by Waterose
Twelve Month Baseline Water Quality Study for Salmonids in the lower Sooke River Watershed (Victoria Times Colonist Enviro News)
Twelve Month Baseline Water Quality Study for Salmonids in the lower Sooke River Watershed (Sooke Mirror)
Water Quality Project on Musqueam Salmon Stream in Urban Vancouver
Analysis of Coliforms and Nutrients in surface waters flowing into Esquimalt Lagoon
Water Quality Monitoring on Ayum Creek, a wild salmon and trout bearing stream, for Society for the Protection of Ayum Creek and Fisheries and Oceans, Canada
Testing the Waters
Story in Sooke News Mirror, March 28, 2001 about the Automated Water Quality Monitoring Project
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