CHAPTER 2 Stream Quality Study

Transcription

1 CHAPTER 2 Stream Quality Study This chapter sets out the method used to determine the water quality of major streams within the Okanagan Basin. The sampling and analysis as outlined in this section were carried out for the purpose of estimating the annual loadings of nutrients and other constituents to the Okanagan Lake system as discussed in Chapter 12. The analytical results were also used in evaluating the water quality of tributaries and the main valley lakes (Chapter 13). Sampling of the Okanagan River and streams tributary to the Okanagan Lakes and River began in early June, 1969 and continued until October 31, Samples were taken at 41 locations and analysed for physical, inorganic and organic constituents, In order to carry out this program effectively the Federal Water Quality Division established a laboratory at the Kelowna Pollution Control Centre, in 1969 staffed with a chemist and a chemical technician to collect samples and conduct on-site and laboratory analyses. 2.1 SAMPLING LOCATION AND PROGRAMS The forty one (41) stream stations sampled are listed in Table 2.1 along with Universal Transverse Mercator co-ordinates and frequency of analysis. Station locations are also illustrated in Figure 2.1. The frequency of sampling was dependent on flow of the stream or the volume of industrial and municipal discharges. A number of sampling stations were located on streams which are dry during a major part of the year. These locations were sampled less frequently. Composite grab samples were obtained from the main flow of the stream. Samples to be sent to laboratories were preserved and packed in ice for shipping. Analyses were conducted in the field and at laboratories in Kelowna and Calgary. Measurement of temperature, ph, conductance and a partial treatment of samples to determine the oxygen concentration were carried out at the time of sampling. The standard Winkler test for the determination of dissolved oxygen was completed in the laboratory. The laboratory at Kelowna was established and began operation in May, 1969, housed in a 14 foot trailer. In February, 1970 the laboratory was moved into the new Pollution Control Centre. At this laboratory the following analyses were performed: ph, temperature, conductivity, turbidity, completion of the dissolved oxygen test, and biochemical oxygen demand. The methods of analyses used were identical to those employed in the Calgary laboratory which are described in this report.

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3 TABLE 2.1 SAMPLING LOCATIONS AND FREQUENCY

4 SAMPLING LOCATIONS AND FREQUENCY (CONT'D)

5 Samples were prepared (when full analysis were required) for heavy metal analysis by passing a 1000 milliliter aliquot of sample through a 0.45 micron cellulose acetate filter, prewashed with nitric acid, and acidifying with 2 mls of concentrated nitric acid. Samples were forwarded to Calgary for analysis. Sampling schedules were arranged so that samples could be delivered to the Calgary laboratory within 24 hours of sampling. Samples left Kelowna at 8:00 p.m. by bus and arrived at the Calgary Terminal at 6:00 a.m. the next morning. Messenger service then delivered the samples at 8:00 a.m. to the Calgary laboratory. The methods of analyses used in the Water Quality Laboratory at Calgary are described in tabular form (Table 2.2). The minimum detectable concentrations for each water quality parameter and their respective accuracy limits are described in Table 2.3. TABLE 2.2 METHODS OF ANALYSES WATER QUALITY LABORATORY AT CALGARY NOTE: All values expressed as mg/l unless otherwise stated.

6 TABLE 2.2 METHODS OF ANALYSES WATER_QUALITY LABORATORY AT CALGARY (CONT'D) Definition of terms used In methods: Dissolved -(a) Heavy Metal Analysis. The sample was filtered the same day as sampling in the Kelowna field laboratory through a 0.45 micron cellulose acetate filter. This filter was pre-washed with dilute HNO 3 2 mls concentrated HNO 3 per liter of sample was then added at a preservative. (b) General Dissolved Analysis (Cl, SO 4, F, etc.) No field pretreatment. Sample was filtered through a filter in the Calgary Laboratory. Total - For this program, total anaylsis was that analysis performed on a shaken sample.

7 Solvent Extraction - MIBK - APDC extraction as outlined in reference 2, page Methods of analyses for Okanagan stream sampling program, Task 131, as used in the Kelowna field laboratory in Kelowna, B.C. ph - As described in the Calgary laboratory. Conductance - As described in the Calgary laboratory. Temperature - As described in the Calgary laboratory. Turbidity - As described in the Calgary laboratory. Dissolved Oxygen - Standard Kinkier method with the azide modification. (1) Biochemical Oxygen - 5 day incubation using the standard Winkler method Demand with the azide modification. (1) * Numbers in parenthesis refer to references as indicated. TABLE 2.3 MINIMUM DETECTIONS LIMITS AND LIMITS OF ACCURACY

8 TABLE 2.3 MINIMUM DETECTIONS LIMITS AND LIMITS OF ACCURACY (CONT'D) NOTE: Coefficient of variation is the ratio of the standard deviation to the arithmetic mean expressed as a percentage.

9 2.2 STREAM QUALITY DATA A statistical summary of the analytical results for the 41 sampling stations are included in Appendix B. The data has been summarized for 1969, 1970 and 1971 in which the maximum and minimum concentrations, range and number of values have been calculated for each water quality parameter.