Surprisingly little is known about the concentrations of many dissolved trace elements in rivers and what processes control those concentrations. Our work has examined the mechanisms of seasonal concentration variations in the Mississippi River, the effect of weathering processes on dissolved trace element ratios, and the global variability of concentrations. Our work has been supported by the Environmental Protection Agency, the National Science Foundation, the US Department of Agriculture, and the US Geological Survey. Composition of colloids and suspended particles. We're working with a new technique called field flow fractionation that allows colloidal particles to be size fractioned for further analysis.
Colloids are fine sub-micron sized particles usually kept in suspension by Brownian motion.
Colloidal particles appear to be very important in the transport of certain trace elements and other contaminants in the environment. This work is supported by the National Science Foundation. Development of shipboard analytical methodologies for trace element analysis. Conventional means of trace metal analysis tend to involve manipulative preconcentration steps and require sensitive analytical equipment. We've developed new automated methods for some elements which considerably simplify the analytical process to the point where we can perform analyses in the field in near real time.