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State of the Water Quality

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The state of the water quality was judged by comparing values to the Ministry of Environment, Lands and Parks' Approved and Working Criteria for Water Quality (Nagpal et al., 1995). Indicators not discussed below met their criteria and did not display any noticeable trends. These include: arsenic, barium, beryllium, chloride, cobalt, fluoride, lithium, magnesium, molybdenum, nickel, nitrate/nitrite, total dissolved nitrogen, pH, total phosphorus, potassium, filterable residue, fixed filterable residue, fixed non-filterable residue, selenium, silica, sodium, specific conductivity, strontium, and sulphate.

Flow (Figure 2) values were highest during spring freshet (May-July). Peak flow values were similar most years except for lower values in 1989 and 1991.

Total alkalinity (Figure 3) and calcium (Figure 9) concentrations indicate a low sensitivity to acid inputs.

Total aluminum (Figure 4) values exceeded the 5 mg/L total aluminum criterion for wildlife, livestock and irrigation only once (June 16, 1992) during peak flow and suspended sediment. Peak aluminum values corresponded to peak non-filterable residue and turbidity. This suggests that the aluminum was in a particulate form and probably not biologically available and would be removed by the turbidity removal needed before drinking. Dissolved aluminum should also be measured for direct comparison to criteria for drinking water and aquatic life.

Total cadmium (Figure 8) had minimum detectable limits (0.0001 mg/L & 0.001 mg/L) 2 to 33 times above the aquatic life criteria (0.00003 to 0.00005 mg/L). All values between 1986 and 1991 are questionable due to suspected preservative vial contamination. Since 1991, peak cadmium values corresponded to peak non-filterable residue and turbidity. This indicates that the cadmium was in a particulate form and probably not biologically available. To evaluate the aquatic life criteria accurately, the minimum detectable limit should be lowered to at least one-tenth of the lowest criterion, and dissolved cadmium should also be measured.

Total chromium (Figure 11) values between 1990 and 1991 are suspect due to preservative vial contamination. Since then, 45% of the values have exceeded the 0.002 mg/L criterion for phyto- and zoo-plankton. High chromium values corresponded to high non-filterable residue and turbidity. This indicates that the chromium was in a particulate form and probably not biologically available.

Apparent colour (Figure 13) met the 100-unit recreation (maximum) criterion except on one occasion (May 22, 1990). Also, the 15-unit drinking water and recreation criterion was met at least 60% of the time. All criteria are given as true colour values, where turbidity is removed before measurement. High apparent colour values occurred in samples with high turbidity, and thus true colour would have been much lower. True colour should be measured to compare the data to the criteria effectively.

Total copper (Figure 14) values were high due to preservative vial contamination between 1986 and 1991. Between 1991 and 1994, one value (June 16, 1992) exceeded the upper (0.008 mg/L) aquatic life criterion, and 41% of the values exceeded the lower (0.003 mg/L) aquatic life criterion. High copper and non-filterable residue and turbidity occurred together. This indicates that the copper was in a particulate form and probably not biologically available.

Hardness (Figure 16) values were within the optimum range for drinking water (80-100 mg/L as CaCO3) 36% of the time. Sixty-one percent of the values were above this range. Lowest hardness values took place in the summer and highest values occurred in the winter.

Total iron (Figure 17) values exceeded the 5 mg/L criterion for irrigation 7% of the time, while the 0.3 mg/L drinking water and aquatic life criterion was exceeded 77% of the time. High values of iron corresponded with high non-filterable residue and turbidity. This indicates that the lead was in a particulate form and probably not biologically available and would be removed by the turbidity removal needed before drinking.

Total lead (Figure 18) exhibited high values between 1986 and 1991 due to preservative vial contamination. Since then, the aquatic life criterion was exceeded once (June 16, 1992) when non-filterable residue and turbidity were high. This indicates that the lead was in a particulate form and probably not biologically available.

Total manganese (Figure 21) values exceeded the 0.2 mg/L criterion for irrigation once (June 16, 1992). Also, the 0.1 mg/L criterion for aquatic life was exceeded 9% of the time, and the 0.05 mg/L criterion for drinking water was exceeded 27% of the time. High manganese and non-filterable residue and turbidity occurred together. This indicates that the manganese was in a particulate form and probably not biologically available and would be removed by the turbidity removal needed before drinking.

Non-filterable residue (Figure 30) values exceeded the 25 mg/L criterion for good fisheries 71% of the time due to high flows during freshet. The patterns of non-filterable residue and turbidity (Figure 41) were nearly identical.

Water temperature (Figure 40) exceeded the 15°C upper aesthetic limit for drinking water and the lower limit for recreation 6% of the time. This means that the water was cool enough to be aesthetically pleasing for drinking, but too cold for water-contact recreation such as swimming.

Turbidity (Figure 41) values exceeded the 50 NTU criterion for recreation 7% of the time due to high flows in spring freshet. The 5 NTU aesthetics criterion for drinking water was exceeded 69% of the time, and the 1 NTU health criterion for drinking water was exceeded 87% of the time. Turbidity removal and disinfection are needed prior to drinking.

Total zinc (Figure 42) exhibited high values between 1986 and 1991 due to suspected preservative vial contamination. Since 1991, one value (June 16, 1992) exceeded the 0.03 mg/L fish and invertebrates criterion and the 0.015 mg/L algae criterion. Non-filterable residue and turbidity were high then, indicating that the zinc was in a particulate form and probably not biologically available.

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