The effect of manganese oxide scavenging on the distribution and sedimentation of molybdenum in saanich inlet, british columbia

This study investigated the process by which molybdenum was removed from sea water in Saanich Inlet, an anoxic fjord, whose basin sediments are enriched in molybdenum. Water samples were collected in the inlet from July 1971 to April 1972 at about two month intervals and were analyzed for pH, salinity, temperature, dissolved and suspended molybdenum, suspended manganese and iron, and dissolved oxygen and hydrogen sulphide. A new technique for the determination of dissolved and suspended molybdenum was developed. The data showed a negative correlation between dissolved molybdenum and suspended manganese, and a positive correlation between suspended molybdenum and suspended manganese. This suggested that molybdenum was being scavenged from sea water by suspended manganese oxides. The distribution of molybdenum in the basin surface sediments was qualitatively correlated to the distribution of suspended molybdenum in the overlying basin water. During about September to December, the molybdenum profile was described by a two layer system. In the top 75 m layer the molybdenum followed the salinity profile. Below 75 m the distribution was described by a one dimensional mathematical model. The yearly deposition of molybdenum in the basin sediments was calculated from the estimated sediment deposition rate. This value was not inconsistent with that calculated from the rate molybdenum is scavenged by manganese oxides from the basin water.Science, Faculty ofChemistry, Department ofGraduat