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Environmental Investigation of the Quinsam Watershed

Prepared by the Environmental Sciences Group, Royal Military College, Kingston, Ontario and the University of British Columbia, for the Canadian Water Network.

Published April 2010

Dr. William R. Cullen of the University of British Columbia led the project, and in the field work, analysis and report creation was assisted by Vivian W.-M. Lai.

Executive Summary

An environmental investigation of the Quinsam watershed, located on Vancouver Island, British Columbia was directed by Dr. William R. Cullen.

This study was initiated to investigate whether the mine was introducing arsenic into the watershed and if so, what the effects of arsenic input were on biota in the watershed. To determine natural and anthropogenic elemental loadings in sediments in the area, sediments were collected from a number of background lakes and lakes on the mine property, including the lake of highest concern, Long Lake. These results were compared with waste material from the mine site. The uptake of arsenic was investigated by using mussels in both short and long-term monitoring studies. A short-term caged mussel experiment was designed to investigate the potential for arsenic uptake, while long-term monitoring of mussels downriver of the mine was used to investigate current and historical arsenic loading in mussels.

Anthropogenic inputs of elements, including arsenic, to the watershed were identified after collected lake sediments were analyzed. In particular, Long Lake sediments were found to be elevated in arsenic. Further speciation analysis and bioaccessibility, or solubility, testing indicated that the introduced arsenic contamination can be easily solubilized and is more soluble than arsenic in the waste rock from the mine site. These speciation and bioaccessibility tests indicate that Long Lake sediments have forms and solubilities of arsenic similar to those from surrounding lakes. Further study is required to identify which of many potential sources around Long Lake is responsible for the elevated arsenic concentrations. The lake that flows into Long Lake, No Name Lake, was previously identified as also having elevated arsenic concentrations (Nordin, 2006) and the current study obtained similar results.

Elevated arsenic concentrations in sediments were found to correlate with elevated arsenic concentrations in biota. During the short-term caged mussels experiment higher arsenic loadings were found in mussels in Long Lake than in surrounding Quinsam watershed lakes. Higher loadings were seen in mussels collected from the Quinsam River in relation to the same species of mussel monitored in a nearby watershed, Simms Creek.

Arsenic concentrations are elevated in Long Lake as a result of acid rock drainage and other chemical process associated with mine waste. The high arsenic levels are associated with high concentrations of sulphate. The arsenic is available to bivalves, and presumably other biota. Further studies to identify the points of arsenic input should be undertaken to allow for corrective action. In particular sediment cores would provide evidence of the extent of anthropogenic arsenic inputs since the mine opening.

Download the full report here.