Ionophore Sorption and Desorption in Coastal Plain Soils of Mid-Atlantic Region of the United States.

Veterinary anticoccidials, biochemically known as ionophores are widely used in poultry feed at therapeutic levels to treat the protozoan disease Coccidiosis and at sub-therapeutic levels for growth-promotion. Some of these ionophores are excreted, without undergoing any metabolism, and have been found in agricultural watersheds, presumably from land application of the manure. Hence they are potential markers for agricultural pollution as they are exclusively used for animal rearing purposes. In our previus study we found Monensin in the highest concentration amongst other ionophores quantified and characterized in the mid-atlantic region of the United States. Hence our objective for this project is to determine the effect of soil types/characteristics on sorption and desorption of monensin in coastal plain soils. Sorption and desorption batch isotherm study is being conducted using soils representing those of the Mid-Atlantic region of the United States. Liquid chromatography-triple quadrupole mass spectrometer is being used to quantify the amount of monensin sorbed and desorbed during the study.  From the sorption and desorption studies we will report the effect of soil pH, cation exchange capacity, soil depth and texture compounded with organic matter on the sorption-desorption properties of monensin. We are also interested to know how monensin partitions into different phases of these soils and determine the partition co-effecients (Koc and Kd).