Metal(loid)s in sediment, lobster and mussel tissues near historical gold mine sites

• Historical gold mining in Nova Scotia has left a legacy of marine contaminants.
• Future industrial coastal developments may disturb these contaminants.
• Metal(loid) contaminants were measured in sediment, lobster and mussel tissues.
• Current sediment metal(loid) concentrations exceed Canadian SQGs.
• Current lead and arsenic concentrations in marine biota exceed CFIA guidelines.

Previous studies near historical gold mining districts in Nova Scotia have identified significant enrichment of metal(loid)s in coastal marine sediments. Most of this inventory is buried below biologically active zones, although in some areas arsenic has bioaccumulated in marine biota resulting in localised bivalve shellfish closures. Isaacs Harbour is poised for future industrial development, but before potential impacts are predicted, current marine baseline conditions must be determined. To address this gap, this study established a baseline using surface sediments and biota (mussel and lobster tissues), to provide a broader picture of metal(loid)s in the marine environment. Results confirmed previous studies showing that most sediment metal(loid) concentrations still exceeded Canadian Marine Sediment Quality Guidelines, and also provided evidence of Canadian Food Inspection Agency fish tissue exceedances of arsenic in lobster and lead in mussel tissues indicating that some bioaccumulation of legacy contaminants in marine biota continues to the present day.