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The overall goal of this project is to identify likely mechanisms that cause the greater than expected mobility and persistence of reproductive hormones in the environment. This information is necessary to develop manure handling best management practices, and developing predictive models.<P>
Three experimental objectives were formed to achieve the project goal:<OL> <LI> Determine the sorption characteristics of 17beta-estradiol (E2) and its glucuronide (E2G) and sulfate (E2S) conjugates to soil in the presence and absence of dissolved organic carbon (DOC) and colloidal organic carbon (COC) originating from animal manure. This first objective will test the hypothesis that if the sorption of estrogens are related to the presence of liquid manure (slurry)-derived DOC and COC, then estrogen in the presence of high amounts of manure DOC or COC will increase their mobility. Laboratory experiments that test this first hypothesis will be an output, and will answer the question, "Does DOC and COC from lagoon slurry enhance the mobility of estrogens in mineral soil and thus increase the potential for off-site movement" An additional hypothesis that this first objective will test is, "if conjugated hormones are more soluble than their deconjugated forms, then they will not bind strongly to soil be more mobile. Outputs testing this second hypothesis will be laboratory experiments that answer the question, "Do estrogen conjugates promote the apparent mobility or persistence of deconjugated estrogens in soil" <LI> To measure the degradation of E2, E2G, and E2S in soil in the presence of manure slurry-derived DOC and COC. The hypothesis tested of this second objective is, "if estrogenic hormones are bound to DOC or COC and not easily accessible to microbial processes, then estrogens in the presence of high amounts of DOC or COC will increase their persistence in the environment compared to free aqueous estrogens." Outcomes from this second objective will be laboratory experiments that answer the question, "Does DOC and COC fractions of manure slurry offer estrogenic hormones protection from microbial degradation and increase their longevities in the soil or manure storage facilities" <LI> Determine how land application strategies for manure slurry influence the fate and transport of estrogens through soil to tile drainage and how this relates to manure slurry contents of DOC, COC, and estrogen conjugates. The hypothesis that this objective will test is, if the mobility of estrogens in soil is related to hormone conjugates and the presence of DOC or COC and the retention time in the near-surface horizons, then the detections of estrogens will be related to manure application on tile drainage fields, manure-borne DOC and COC, and increased drainage rates. The outcome of this objective will be a field study, where manure is applied to the soil and E2, E2S, and E2G are measured in runoff and tile drainage and correlated to DOC and COC contents. </ol> The research question that will be answered is, "Do estrogens and their conjugates from manure slurries applied to fields move with gravity water into tile drains and into surface waters."
NON-TECHNICAL SUMMARY: Hormone detections have been associated with manure management practices; whish is of particular concern to the animal agriculture industry. The primary estrogen, E2, is potent to sensitive organisms at part per trillion concentrations. Laboratory studies have determined E2 to be short-lived in soils; nonetheless, it is frequently detected in the environment. This apparent disparity between laboratory and field studies could be the result of unknown conjugate and colloidal transport processes in complex field systems that are not usually observed in the laboratory. Small organic matter particles, or colloids, can potentially attach to hormones protecting them from microbial degradation or helping them move freely in the soil. Also, as the animal eliminates hormones from their body, they are predominantly in the conjugated form. These conjugated forms of the hormone are potentially much more mobile then the deconjugatged forms, because they can readily dissolve in water compared to the deconjugated forms. This project will evaluate how hormone conjugates and colloids may contribute to the greater than expected mobility and persistence of hormones in the environment. Laboratory and field experiments will be used to achieve the overall goal of this project. The results of this project can provide improved manure management strategies that reduce releases of reproductive hormones from manure. Results will be presented at national scientific meetings and submitted for publication in scientific journals. Also, an aim for this project is to develop practical solutions/applications evolving from our basic research. North Dakota State University is the state's Land Grant institution that has an Extension mission to provide outreach education to make basic research applicable. In the past, the PDs have participated in several Extension/Outreach talks to farmers, consultants, etc. to educate them about hormones and animal manures. The PDs feel that it is important to actively participate in this Land Grant mission through extension/outreach activities and demonstrations, such as on the Discovery Farm.
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APPROACH: The fist and second objective will be achieved using laboratory experiments in which the sorption and persistence, respectively, of E2, E2S, and E2G to soil is observed in the presence of animal manure slurry. Radioisotope methods will be used with batch sorption experiments in soils that have been sterilized. Various concentrations of aqueous dissolved estrogens and manure slurry will be combined with soil, and the sorption kinetics and sorption equilibrium processes will be identified. Also, incubation experiments will be done under sterile/natural and aerobic/anaerobic conditions to identify the degradation pathways. Radiolabel forms of E2G and E2S will first need to be synthesized for the batch and incubation experiments. The third objective will be achieved with a field experiment in which existing subsurface tile-drainage lines are accessed and sampled. Also, surface runoff from the field will be sampled. Swine (Sus scrofa domesticus) manure slurry will be injected or surface applied to the field and water samples from the subsurface tile drain, and run off will be taken, preserved with formaldehyde, and analyzed with liquid chromatography equipped with tandem mass spectrometers. Results from the field study will be correlated with the manure DOC and COC, and compared to laboratory experiments. Results will be presented at national scientific meetings to further the scientific research in this area. Also, an aim for this project is to develop practical solutions/applications evolving from our basic research. North Dakota State University is the state's Land Grant institution that has an Extension mission to provide outreach education to make basic research applicable. In the past, the PDs have participated in several Extension/Outreach talks to farmers, consultants, etc. to educate them about hormones and animal manures. The PDs feel that it is important to actively participate in this Land Grant mission through extension/outreach activities and demonstrations, such as on the Discovery Farm.