| Abstract/Description or Keywords |
The Fraser River flows through a vast portion of the southern half of British Columbia, from the Rocky Mountains to the Pacific Ocean. The water quality monitoring site at Red Pass (located just below Moose Lake in the headwaters of the Fraser River) is the first of five long-term monitoring stations on the Fraser River. The remaining four monitoring sites are located at Hansard, Stoner, Marguerite, and Hope. This site represents a relatively pristine monitoring station, with no significant anthropogenic activity occurring upstream from this location. The primary purpose of the site is to provide an indication of ambient conditions that can be compared with water quality at downstream sites. The water quality trends identified below have not yet been confirmed by statistical analysis. CONCLUSIONS: • There was an increasing trend in nickel concentrations since about 1994, although it has been reduced in magnitude in recent years. The cause of this increase is unclear, but concentrations of total nickel remain well below guideline levels for aquatic life. • There may be slight increases in cobalt, rubudium, and dissolved nitrogen and dissolved sulphate. • There appears to be a decreasing trend in lead concentrations and a possible increase in manganese. These trends may be related to the elimination of leaded gas and the use of a manganese-based additive. • Specific conductivity also appeared to be increasing over time, but the levels seem to have remained steady since about 1992. Similar patterns were noted for hardness. • The Fraser River at Red Pass has a low sensitivity to acid inputs (has a high buffering capacity) based on its relatively high total alkalinity and calcium concentrations. • Exceedances of water quality guidelines by metals such as total copper, total iron, and total silver, appear to be associated with elevated turbidity levels, indicating that these metals were bound in particulate matter, and therefore not available to biota and not of concern. Many metals that appeared to have values that exceeded guidelines in the past, have been shown to meet guidelines since lower detection limits have been utilized, and confidence in results have coincidentally improved. • As there are no major human activities upstream from the Red Pass site, the measured concentrations of all metals would appear to be due to natural erosion processes in the upper watershed. Occasional high turbidity values are also attributed to natural erosion processes. • All fecal coliform values were very low, indicating little fecal contamination of the Fraser River was occurring upstream from Red Pass. • True colour has only been measured at Red Pass since 1997, but all values since that time have been below the aesthetic guideline for drinking water quality. • Another recent evaluation of water quality at the Red Pass site, using the Water Quality Index as an assessment tool, ranked the water quality as Good to Excellent. Benthic populations measured downstream from the site in 1996 also indicated excellent water quality, and the population itself was considered to be a “reference” (i.e. undisturbed) population. RECOMMENDATIONS: • Continue monitoring at this station for the present suite of water quality indicators, because the Red Pass site provides critical ambient water quality data necessary for interpreting data collected downstream in the Fraser River, as well as elsewhere in the province. • Initiate monitoring of dissolved aluminum and hexavalent and trivalent chromium to enable the comparison of these metals to existing water quality guidelines. • Continue to monitor extractable concentrations of all metals, including cadmium, to allow comparisons to total and dissolved concentrations of metals to be made (useful for determining potential impacts on aquatic life and/or drinking water). |
