||Anderson-Nichols and Co., Inc., Palo Alto, CA. ;Ecosystem Research Inst., Logan, UT. ;AQUA TERRA Consultants, Mountain View, CA.;Environmental Research Lab., Athens, GA.
The Metals Exposure Analysis Modeling System (MEXAMS), linking a complex speciation model with an aquatic transport/fate model, should help discriminate between the fraction of metal that is dissolved and in bioavailable form and the fraction that is complexed and rendered relatively nontoxic. The MEXAMS model has been tested with data from three rivers to determine its ability to simulate fate, transport, and speciation of heavy metals in river systems. The rivers selected for study were the Naugatuck River in Connecticut and the Ten Mile River in Massachusetts, both of which receive electroplating and metal finishing wastes, and the White River in Utah, which receives metal loadings from natural sources. The report documents the tests as case studies to guide future users in the application of the model. In addition, the program has been enhanced by addition of sediment settling/resuspension to the aquatic transport submodel EXAMS.