Accurately quantifying net loads in tidal systems is difficult owing to the high variability in constituent concentrations over the vastly different time scales present in these systems. Perhaps most difficult is the measurement of fluxes over the tidal time scale. Therefore, numerous measurements are required in a brief amount of time to accurately quantify constituent fluxes between a tidal wetland and its surrounding waters. This is an important issue because wetlands are known to increase mercury methylation and CALFED intends to restore many acres of the Delta to tidal wetlands. The development of an instrumentation package that can be used to monitor in situ measurement of the transport of these contaminants would offer a valuable tool to determine which management actions will best minimize the transport of these contaminants. We have collected data to determine the fluxes of total mercury (Hg) and methyl-Hg (MeHg) in dissolved and particulate phases at Browns Island, a tidally influenced brackish marsh in the San Francisco Bay-Delta. Our field deployment package consists of an upward-looking current profiler to quantify water flux and instruments to measure the spectral absorption and fluorescence and a suite of chemical parameters of the water at 30-minute intervals. We infer Hg and MeHg concentrations by using multivariate analysis of and the optical properties and comparing them to the results of discrete samples taken hourly during each deployment. Results indicate that in situ measurements can be used to predict MeHg and THg concentrations in a tidal wetland slough in the filtered and unfiltered fractions. Despite seasonal differences in constituent concentrations and the optical signatures, these correlations remain robust throughout the year. These correlations are used to generate high-resolution time series for each Hg species, which then are used to calculate net tidal fluxes.