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Fate and transport of steroid hormones in the environment as affected by manure management and application strategies
The goal of the research was to determine the effects of rainfall timing, manure handling (composting and stockpiling), and tillage (disk, plow and no-till) on the fate and transport of steroid hormones from manure amended agricultural fields through overland runoff and leachate. Manure, runoff, soil, and leachate samples were analyzed for 17 steroids and metabolites. Two rainfall simulations were conducted one day (1 DAT) and one month (30 DAT) after manure application in 2008 to evaluate the effects of rainfall timing, manure handling and application strategies on the movement of steroids through runoff. Analyses of manure samples suggested that composting may be an effective way to reduce steroid levels. When all the steroids or metabolites were grouped together, runoff analysis found 47% frequency of detection from 30 DAT sampling compared to 30% frequency of detection from 1 DAT sampling event. However, none of the steroids were detected in more than 9% samples from any sampling event. There were slightly more frequency of detection in runoff from 1 DAT in the stockpiled treatment compared to composted treatment. A greater frequency of detection from untreated manure during 30 DAT suggested that desorption and microbial biodegradation may play a role in mobilizing specific compounds. Among the tillage treatments, there were greater detections from the no-till during 1 DAT, while detections were more from disk during 30 DAT. None of the results were supported statistically due to lack of frequency of detection. Due to lack of detections in 2008, an additional rainfall simulation study was conducted during 2009 using the synthetic estrogen 17&agr;-ethynylestradiol as surrogate to evaluate the effects of tillage practices and manure application on the movement of steroids in overland runoff. Results from the study suggested that incorporation of manure after land application can be an effective way to reduce the movement of steroids in environment. A leaching study was conducted with 2.4 m deep percolation lysimeters following a single manure application in 2008. Soil and leachate samples were collected to investigate the vertical movement of steroids using composted and stockpiled manure from treated cattle. Steroids were observed in the leachate and soil samples with only 5% and 10% detection frequency, respectively. A higher frequency of steroids in detected soil samples were likely related to the higher sorption affinity with soil particles.
Agricultural engineering|Environmental engineering
Biswas, Sagor, "Fate and transport of steroid hormones in the environment as affected by manure management and application strategies" (2012). ETD collection for University of Nebraska - Lincoln. AAI3521926.