Fate of Hormones in a Field Receiving Dairy Manure and Poultry Litter: Effect of Surface-Application and Subsurface Injection.

Hormones are endocrine disrupting compounds which can disrupt the sexual development and robustness of populations of aquatic organisms.  Hormones are naturally sourced from animal manure, and manure application to agricultural fields can concurrently apply hormones with beneficial nutrients.  Hormones enter environmental systems mainly through runoff and often transform in the environment, therefore it is important to detect both parent compounds and metabolites during analysis.   No till and reduced tillage cropping systems restrict the movement of sediments and their related pollutants from agricultural fields, however these cropping systems practice surface application of manure.  Subsurface application of animal manure is becoming an increasingly popular technique to avoid the pollution associated with the surface application while maintaining no-till character.   A field scale rainfall simulation study was conducted to investigate the impact of manure surface application and subsurface injection on the occurrence of 11 hormones, hormone precursors, and conjugated hormones in soil and surface runoff.  Field plot (1.5x2m) treatments included subsurface injected poultry litter, surface applied poultry litter, subsurface injected dairy manure slurry, surface applied dairy manure slurry and a control.  Poultry litter was applied at 3 tons/acre and dairy manure slurry was applied at 6,000 gal/acre.  Thirty min of runoff samples were collected during the simulated rainfall from each plot at the day of manure application and 7 days after manure application.  Rainfall intensity for the simulations was 70 mm/h. Immediately after each surface runoff collection, soil samples from 0-5cm and 5-20cm were collected from each plot.  The target compounds were extracted from the soil and manure using high pressure solvent extraction followed by cleaning up with solid phase extraction.  The soil and manure extracts were analyzed by LC/MS/MS.  It is anticipated that surface application of manure will result in increased hormone concentrations in runoff compared to subsurface injection, however the hormones in the soil from the manure subsurface injection will persist for longer, as there is decreased microbial activity in the subsurface.