Abstract
Elevated concentrations of heavy metals in water caused by mining activities create significant risks to the environment. Traditional biological methods used to assess toxicity caused by heavy metals toxicity in aquatic environments are lengthy and labor-intensive. Real-time biomonitoring approaches eliminate some of these limitations and provides an opportunity for unattended, continuous monitoring of toxicity. This study describes the long term performance of a biosensor developed for real-time detection of heavy metal toxicity in an aquatic environment. The biosensor was based on the microbial fuel cell (MFC) concept. After laboratory validation of the biosensor, it was deployed in Junction Creek, Sudbury, ON. Three sites were selected for biosensor installation corresponding to upstream (low metal content) and downstream (high metal content) locations within the creek. The biosensors installed at each site were able to detect, in real-time, temporal changes in the toxicity of the creek at these locations over a 2 months period. The biosensor response was compared to conventional toxicity assays and analytical measurements of metal concentration. We conclude that the biosensor can detect abrupt changes (increases) in concentration of heavy metals, such as copper. Finally, a newly engineered design of the biosensor incorporating all the elements required to make a full transition from the laboratory to the field while ensuring autonomous operation for at least 6 months will highlighted.