Ionophore Sorption and Desorption in Coastal Plain Soils.

Veterinary anticoccidials are used in poultry feed at therapeutic levels to treat disease and at sub-therapeutic levels for growth-promotion. They are found in significant quantities in animal manure. Although little published research exists on their persistence after manure is land applied, they are rapidly becoming identified as an emerging contaminant. Therefore, our objectives were to determine the effect of soil texture and pH on sorption and desorption of monensin, a commonly used ionophore, in coastal plain soils. A sorption and desorption batch isotherm study was conducted using different soil textures found on the Delmarva Peninsula. The study was conducted on soils collected from the A and B horizons separately. Liquid chromatography-triple quadrupole mass spectrometer was used to quantify the amount of monensin sorbed and desorbed during the study. Variation in the sorption and desorption patterns based on different soil textures, % organic matter, cation exchange capacity and other soil properties will be presented.