Geochemistry of tungsten and molybdenum during fresh water transport and estuarine mixing

• The geochemistry of tungsten (W) in the environment is still poorly studied. Tungsten is little mobile and usually occurs in low concentrations in natural waters. For this study, we analyzed W together with molybdenum (Mo) in the dissolved and particulate fraction of two boreal estuaries during different seasons. Additionally, we sampled first-order streams, draining different landscape types, and the receiving northern Baltic Sea. Furthermore, surface sediment from the estuaries was analyzed to get a comprehensive overview of the distribution of W and Mo in a boreal environment.Both elements showed different distribution patterns during different seasons. While they decreased in dissolved concentrations during spring discharge, their concentrations were elevated in winter and exhibited non-conservative behavior along the salinity gradient in the estuaries. In the particulate fraction, we found an opposing behavior for Mo and W, with higher particulate W and lower particulate Mo during spring discharge.Molybdenum and W underwent fractionation from land to sea, indicating different mobility for these oxyanions. The Mo/W ratio in the dissolved fraction was mainly determined by the Mo concentration as the W concentration varied only in a narrow range from first-order streams to the Bothnian Bay. In the particulate fraction, the Mo/W ratio appeared to be affected by scavenging processes and showed only small variations. 

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Geokemi (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Geochemistry (hsv//eng)

Nyckelord

Tungsten

Molybdenum

Suspended particles

Estuarine mixing

Applied Geochemistry

Tillämpad geokemi

Publikations- och innehållstyp

vet (ämneskategori)

ovr (ämneskategori)