SURVEY OF TRACE-METAL CONTENTS OF SUSPENDED MATTER IN ST LAWRENCE ESTUARY AND SAGUENAY FJORD

Trace metal contents ((Mn, Zn, Pb, and Cd) of suspended particulate matter were measured in the upper St. Lawrence estuary and Saguenay fjord. In the estuary, elution of the trace metal fraction adsorbed on particles seems to be mostly responsible for the significant differences in concentrations observed at the freshwater-saltwater boundary. In the Saguenay fjord, particles from deep waters are enriched with trace metals, especially Mn, compared with those from surface waters. This enrichment is probably due to Mn oxidation and simultaneous scavenging of the other trace elements. High Pb and Cd levels in particles of surface waters of the fjord seem to depend mostly on their high affinity for the rich organic matter.