1a. Objectives (from AD-416):
Develop methods for estimation of release rates of emerging contaminants and trace metals from soils having different properties; (2) incorporate release rate algorithms into appropriate SWAT sub-models; and (3) provide specific scenarios for model evaluation of different emerging contaminants, trace metals, and soils.
1b. Approach (from AD-416):
The Soil and Water Assessment Tool currently does not model the transport and fate of emerging contaminants or trace metals. To develop a modeling routine to address this, adsorption and release parameters will be determined for various pesticides and trace metals in differing soils. Parameters to be determined include those addressing compound adsorption to soils (i.e., distribution coefficients, Kd; determination of Freundlich isotherm parameters to describe affinity of compounds in soils); compound retention in soils; and compound release from soils. Compounds to be tested include the trace elements As, Cu, Cr, Cd, Hg, Pb, V, Zn, and V; pesticides for testing include atrazine, metribuzin, alachlor, metolaclor, pendamythelin, and imodolclorpid. Other compounds may be included. Estimations of adsorption, retention, and release parameters can be used to develop appropriate modeling program code for possible incorporation into SWAT.
3. Progress Report:
Soils with varying texture, organic matter, and pH were assembled, and a laboratory analysis method was developed to attempt to determine the release of emerging contaminants (hormones and antibiotics) from soil. When the process is understood, a conceptual model of the process will be developed and incorporated into the SWAT (Soil and Water Assessment Tool) model.