Environ. Sci. Technol. 2007, 41, 3179-3185
In Situ Measurements of Metal Complex Exchange Kinetics in Freshwater KENT W. WARNKEN,† W I L L I A M D A V I S O N , * ,† H A O Z H A N G , † JOSEP GALCERAN,‡ AND JAUME PUY‡ Department of Environmental Science, Lancaster Environment Center (LEC), Lancaster University, Lancaster LA1-4YQ, United Kingdom, and Departament de Quimica, Universitat de Lleida (UdL), Av. Rovira Roure, 191. E-25198 Lleida, Catalonia, Spain
Trace metals were measured in situ in a freshwater river draining a peat catchment (DOC ) 15 mg L-1) using diffusive gradients in thin-films (DGT) devices with a range of gel layer thicknesses (0.16-2.0 mm). The reciprocal of the accumulated mass of each metal varied linearly with the thickness of the diffusive layer. These plots allowed calculation of the thickness of an apparent diffusive boundary layer (ADBL). A constant value was obtained from the plots of Cd, Pb, and Zn. The observed increase in the ADBL for the other metals (Mn
