Comparison of export dynamics of nutrients and animal-borne estrogens from a tile-drained Midwestern agroecosystem.

Concentrated animal feeding operations (CAFOs) are known to be a source of nutrients and hormones found in surface water bodies around the world. While the fate and transport of nutrients have been studied for decades, much less research has been conducted on the fate and transport of hormones. To facilitate a comparison of nutrient and hormone export dynamics from farm fields, nitrate + nitrite (N), dissolved reactive phosphorus (DRP), 17α- and 17β-estradiol (E2), estrone (E1), and estriol (E3) were monitored in a tile drain and receiving ditch for one year on a working farm in north central Indiana.

Hormone discharges from a midwest tile-drained agroecosystem receiving animal wastes.

Manure is increasingly being viewed as a threat to aquatic ecosystems due to the introduction of natural and synthetic hormones from land application to agricultural fields. In the Midwestern United States, where most agricultural fields are tile-drained, there is little known about hormone release from fields receiving animal wastes. To this end, seven sampling stations (four in subsurface tile drains and three in the receiving ditch network) were installed at a Midwest farm where various types of animal wastes (beef, dairy, and poultry lagoon effluent, dairy solids, and subsurface injection of swine manure) are applied to agricultural fields.

Degradation of synthetic androgens 17alpha- and 17beta-trenbolone and trendione in agricultural soils.

17Beta-trenbolone acetate (TBA) is a synthetic androgenic steroid hormone administered as a subcutaneous implant for growth promotion in beef cattle. TBA is converted metabolically to primarily 17alpha-trenbolone and trendione, and excreted in manure from implanted cattle. To predict the persistence of synthetic androgens once land-applied, aerobic degradation rates in two contrasting agricultural soil types (clay loam and a sandy soil) of both trenbolone isomers (17alpha and 17beta) and their primary metabolite trendione were measured and isomer interconversion was assessed.

Sorption of tylosin A, D, and A-aldol and degradation of tylosin A in soils.

Heightened concerns regarding the potential impact on soil and water quality of veterinary antibiotics warrant a better understanding of the environmental fate of antibiotics in soil. Sorption of the macrolides tylosin A (TA), tylosin D, and TA-aldol was measured in several soils and evaluated with respect to soil pH, organic matter content, percentage clay, and cation-exchange capacity (CEC). Tylosin and related compounds exhibit similar sorption characteristics and generally are strongly sorbed, with sorption being well and positively correlated to surface area, clay content, and CEC.

Sorption and degradation in soils of veterinary ionophore antibiotics: monensin and lasalocid.

Monensin and lasalocid are polyether ionophores commonly used in the beef and poultry industries for the prevention of coccidial infections and promotion of growth. These ionophores can exhibit higher toxicity than many other antibiotics; thus, evaluating their fate in the environments associated with concentrated feed operations is important. Sorption of monensin and lasalocid was measured in eight soils of varying physiochemical composition.

Sorption of three tetracyclines by several soils: assessing the role of pH and cation exchange.

Tetracyclines (TCs) are widely used in veterinary medicine for treatment and prevention of disease and are present in animal waste products. Detection of TCs in soil, sediments, and water, and the growing concern of their potentially adverse effect on natural ecosystems have resulted in a need to understand their behavior in aqueous soil systems. TCs have multiple ionizable functional groups such that at environmentally relevant pH values, they may exist as a cation (+ 0 0), zwitterion (+ - 0), or a net negatively charged ion (+ - -), which complicates predicting their sorption, availability, and transport.

Sorption and related properties of the swine antibiotic carbadox and associated N-oxide reduced metabolites.

Carbadox (CBX) (methyl 3-[2-quinoxalinylmethylene]-carbazate N1, N4 dioxide) is a chemotherapeutic growth promoter and antibacterial drug added to feed for starter pigs. Toxicity of CBX and at least one of its metabolites (bis-desoxycarbadox; DCBX) has resulted in a number of studies regarding its stability and residence time in edible swine tissue; however, little is known on its environmental fate pertinent to the application of antibiotic-laden manure to agricultural fields. We measured sorption of CBX and DCBX by soils, sediment, and homoionic clays from 10 mM KCl and 5 mM CaCl2 solutions, sorption of two N-oxide reduced metabolites (N4 and N1) by a subset of soils from 5 mM CaCl2, octanol-water partition coefficients (Kow) of CBX and all three metabolites, and CBX solubility in water and mixed solvents.

Degradation of N,N'-dibutylurea (DBU) in soils treated with only DBU and DBU-fortified benlate fungicides.

N,N'-dibutylurea (DBU) is a breakdown product of benomyl [methyl 1-(butylcarbamoyl)-2-benzimidazole carbamate], the active ingredient in Benlate fungicides, and has been proposed to cause crop damage after the use of Benlate 50 DF fungicide (DuPont, Wilmington, DE). Our research focused on DBU persistence after application into soil. We assessed DBU persistence on direct application of DBU (carbonyl-(14)C) at two concentrations (0.

Assessing N,N'-Dibutylurea (DBU) formation in soils after application of n-butylisocyanate and benlate fungicides.

N,N'-Dibutylurea (DBU) is a breakdown product of benomyl [methyl 1-(butylcarbamoyl)-2-benzimidazole carbamate], the active ingredient in Benlate fungicides, and has been proposed as one cause for crop damage that growers claim to have occurred from the use of Benlate 50 DF fungicide. This study assessed DBU formation upon (1). application of n-butyl-1-[(14)C]butylisocyanate (BIC), the immediate precursor to DBU formation, in four soils at two water potentials (0.