Dissolved trace metals in the water column of Reloncaví Fjord, Chile

Abstract

We analyzed the concentration of dissolved trace metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb) in the water column of Reloncavi Fjord. Sampling was performed during the CIMAR 12 Fiordos cruise in 2006. A total of 36 passive samplers or DGTs (diffusion gradient in thin films) were anchored at four stations along the longitudinal axis of the fjord. The DGTs were deployed at three depths per station and left there for 48 h. The metal contents on each thin film were analyzed using inductively coupled plasma atomic emission spectroscopy. Concentrations were highest in the surface layer at the head of the estuary, which is directly influenced by Petrohue River. Characteristic sequences of the studied metals were defined in the area with the greatest continental influence (Z (5-25 m) = Cu >Mn> Fe > Ni >Pb> Cr > Cd > Co) and in the area with a marine or coastal influence (Z (5-25 m) = Fe > Cu>Mn> Ni >Pb> Cr > Cd > Co). A similar metal sequence was found in the deepest layer: Z (40 m) = Fe >Mn> Cu >Pb> Ni > Cd > Cr > Co. The passive sampling technique using DGTs to determine dissolved trace metals in the sea water provided robust information on the concentrations of the ten metals analyzed.