| Abstract/Description or Keywords |
This report assesses eighteen years of water quality data from the Salmon River near Hyder, Alaska. The Salmon River is a trans-boundary river which flows in a southerly direction from the north central coast of the province, emptying into the north end of the Portland Canal near Hyder, Alaska (USA). The Portland Canal separates the southern portion of the state of Alaska and the north central B.C. coast (Figure 1). Environment Canada has monitored the Salmon River since 1982, collecting approximately 26 samples per year. Environment Canada and the B.C. Ministry of Environment also monitor the nearby Bear River at Stewart, B.C. Data that had quality assurance checks performed (i.e., known errors were removed) were compared primarily to the B.C. Environment's Approved and Working Guidelines for Water Quality, and secondarily to the Canadian Council of Ministers of the Environment Guidelines for the Protection of Aquatic Life Guidelines. Of special interest were water quality levels and trends that are deemed deleterious to sensitive water uses, and specifically, to aquatic life. CONCLUSIONS: _ The water quality of the Salmon River near Hyder, Alaska, over the 1990 up to 2007 sampling period is believed to be largely influenced by natural phenomena such as glacial erosion and mineralization. Freshet events resulted in numerous exceedences in sediment-related water quality parameters, but are not deemed to be a threat to the local aquatic biota. The watershed is sparsely populated and relatively un-impacted by humans except for limited current and historical mining operations. _ The following parameters had statistically significant increasing trends: alkalinity, sodium, magnesium and turbidity. _ Many parameters had statistically significant decreasing trends: aluminum, arsenic, cadmium, chromium, cobalt, cyanide, iron, lithium, sulphate. _ Arsenic, cadmium, chromium, colour, copper, iron, lead and zinc seasonally exceed B.C. or CCME guidelines; the values that exceeded guidelines are largely related to particulate matter (turbidity) during freshet events and unlikely to be bioavailable. _ Total aluminum concentrations exceeded the guidelines that are expressed as dissolved concentrations of the metal. _ A number of metals need to be measured differently if comparisons are to be made to guideline values as they exist. The metals and forms required to be measured are aluminum (dissolved and inorganic monomeric when available), chromium (trivalent and hexavalent), and iron (total and dissolved). _ Cyanide needs to be measured as weak-acid dissociable and as strong-acid dissociable so that comparisons can be made to existing guideline values. _ The increased turbidity during freshet would make it necessary to treat the water to remove turbidity prior to use as a drinking water supply. RECOMMENDATIONS: We recommend the continued monitoring of water quality at the Salmon River near Hyder, Alaska, since it is used to determine trans-boundary effects between British Columbia and Alaska, and assess the environmental impacts of upstream activities such as mining. We also recommend the installation and maintenance of a hydrometric station to assess flow as it has a major influence on water quality in the Salmon River and to assess changing melting patterns over time due to factors such as climate change. Finally, we recommend that concentrations of the following parameters be measured in the following forms: aluminum should be measured as dissolved aluminum, iron as dissolved, and chromium as Cr+6 and Cr+3. |
