@article{lee_kullman_yost_worley-davis_reckhow_2018, title={An object-oriented Bayesian network approach for establishing swine manure-borne natural estrogenic compounds budget}, volume={639}, ISSN={["1879-1026"]}, DOI={10.1016/j.scitotenv.2018.05.209}, abstractNote={A facility-wide estrogen budget model was developed to assess the excretion of natural estrogens by swine in a commercial swine farrowing concentrated animal feeding operations (CAFO) in North Carolina, using an object-oriented Bayesian network (OOBN) approach. The OOBN model is the combination of twelve objects of Bayesian network models, which characterize the estrogen budget flows based on the sow reproductive cycle (i.e., pre-estrus, estrus, and lactation) for the three natural estrogen types [estrone (E1), 17β-estradiol (E2), and estriol (E3)] within each barn. This OOBN model provides a mechanism to quantify the levels of the natural estrogens and their probabilistic distributions with regard to estrogen type, waste sources such as urine, feces, and recycling lagoon slurry, and animal reproductive status. Moreover, the OOBN model allows us to assess the overall contribution of natural estrogen compounds from each operational unit of the CAFO, while accounting for the uncertainties. Results from the OOBN model indicate a rank order of lactating sows > gestating sows > breeding sows in terms of contribution of estrogen loads to the total natural estrogen budget. As to estrogen type, E1 was found as the major estrogen metabolite with the summed concentrations of urine, feces, and flushing slurry wastes exceeding 3000 ng/l > 90% of the time. As to waste sources, the flushing slurry waste was found to be a major contributor of the estrogen budget compared with urine and feces wastes from barn animals.}, journal={SCIENCE OF THE TOTAL ENVIRONMENT}, author={Lee, Boknam and Kullman, Sethw. and Yost, Erin E. and Worley-Davis, Lynn and Reckhow, Kenneth H.}, year={2018}, month={Oct}, pages={815–825} }
 @article{lee_kullman_yost_meyer_worley-davis_williams_reckhow_2018, title={Predicting characteristics of rainfall driven estrogen runoff and transport from swine AFO spray fields (vol 532, pg 571, 2015)}, volume={628-629}, ISSN={["1879-1026"]}, DOI={10.1016/j.scitotenv.2018.02.141}, journal={SCIENCE OF THE TOTAL ENVIRONMENT}, author={Lee, Boknam and Kullman, Seth W. and Yost, Erin E. and Meyer, Michael T. and Worley-Davis, Lynn and Williams, C. Michael and Reckhow, Kenneth H.}, year={2018}, month={Jul}, pages={1460–1460} }
 @article{lee_kullman_yost_meyer_worley-davis_williams_reckhow_2015, title={Predicting characteristics of rainfall driven estrogen runoff and transport from swine AFO spray fields}, volume={532}, ISSN={["1879-1026"]}, DOI={10.1016/j.scitotenv.2015.06.051}, abstractNote={Animal feeding operations (AFOs) have been implicated as potentially major sources of estrogenic contaminants into the aquatic environment due to the relatively minimal treatment of waste and potential mobilization and transport of waste components from spray fields. In this study a Bayesian network (BN) model was developed to inform management decisions and better predict the transport and fate of natural steroidal estrogens from these sites. The developed BN model integrates processes of surface runoff and sediment loss with the modified universal soil loss equation (MUSLE) and the soil conservation service curve number (SCS-CN) runoff model. What-if scenario simulations of lagoon slurry wastes to the spray fields were conducted for the most abundant natural estrogen estrone (E1) observed in the system. It was found that E1 attenuated significantly after 2 months following waste slurry application in both spring and summer seasons, with the overall attenuation rate predicted to be higher in the summer compared to the spring. Using simulations of rainfall events in conjunction with waste slurry application rates, it was predicted that the magnitude of E1 runoff loss is significantly higher in the spring as compared to the summer months, primarily due to spray field crop management plans. Our what-if scenario analyses suggest that planting Bermuda grass in the spray fields is likely to reduce runoff losses of natural estrogens near the water bodies and ecosystems, as compared to planting of soybeans.}, journal={SCIENCE OF THE TOTAL ENVIRONMENT}, author={Lee, Boknam and Kullman, Sethw. and Yost, Erin E. and Meyer, Michael T. and Worley-Davis, Lynn and Williams, C. Michael and Reckhow, Kenneth H.}, year={2015}, month={Nov}, pages={571–580} }
 @article{lee_kullman_yost_meyer_worley-davis_williams_reckhow_2014, title={A Bayesian Network Model for Assessing Natural Estrogen Fate and Transport in a Swine Waste Lagoon}, volume={10}, ISSN={["1551-3793"]}, DOI={10.1002/ieam.1538}, abstractNote={ABSTRACT}, number={4}, journal={INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT}, author={Lee, Boknam and Kullman, Seth W. and Yost, Erin and Meyer, Michael T. and Worley-Davis, Lynn and Williams, C. Michael and Reckhow, Kenneth H.}, year={2014}, month={Oct}, pages={511–521} }
 @article{yost_meyer_dietze_williams_worley-davis_lee_kullman_2014, title={Transport of Steroid Hormones, Phytoestrogens, and Estrogenic Activity across a Swine Lagoon/Sprayfield System}, volume={48}, ISSN={["1520-5851"]}, DOI={10.1021/es5025806}, abstractNote={The inflow, transformation, and attenuation of natural steroid hormones and phytoestrogens and estrogenic activity were assessed across the lagoon/sprayfield system of a prototypical commercial swine sow operation. Free and conjugated steroid hormones (estrogens, androgens, and progesterone) were detected in urine and feces of sows across reproductive stages, with progesterone being the most abundant steroid hormone. Excreta also contained phytoestrogens indicative of a soy-based diet, particularly, daidzein, genistein, and equol. During storage in barn pits and the anaerobic lagoon, conjugated hormones dissipated, and androgens and progesterone were attenuated. Estrone and equol persisted along the waste disposal route. Following application of lagoon slurry to agricultural soils, all analytes exhibited attenuation within 2 days. However, analytes including estrone, androstenedione, progesterone, and equol remained detectable in soil at 2 months postapplication. Estrogenic activity in the yeast estrogen screen and T47D-KBluc in vitro bioassays generally tracked well with analyte concentrations. Estrone was found to be the greatest contributor to estrogenic activity across all sample types. This investigation encompasses the most comprehensive suite of natural hormone and phytoestrogen analytes examined to date across a livestock lagoon/sprayfield and provides global insight into the fate of these analytes in this widely used waste management system.}, number={19}, journal={ENVIRONMENTAL SCIENCE & TECHNOLOGY}, author={Yost, Erin E. and Meyer, Michael T. and Dietze, Julie E. and Williams, C. Michael and Worley-Davis, Lynn and Lee, Boknam and Kullman, Seth W.}, year={2014}, month={Oct}, pages={11600–11609} }
 @article{yost_meyer_dietze_meissner_worley-davis_williams_lee_kullman_2013, title={Comprehensive Assessment of Hormones, Phytoestrogens, and Estrogenic Activity in an Anaerobic Swine Waste Lagoon}, volume={47}, ISSN={["1520-5851"]}, DOI={10.1021/es4026408}, abstractNote={In this study, the distribution of steroid hormones, phytoestrogens, and estrogenic activity was thoroughly characterized within the anaerobic waste lagoon of a typical commercial swine sow operation. Three independent rounds of sampling were conducted in June 2009, April 2010, and February 2011. Thirty-seven analytes in lagoon slurry and sludge were assessed using LC/MS-MS, and yeast estrogen screen was used to determine estrogenic activity. Of the hormone analytes, steroidal estrogens were more abundant than androgens or progesterone, with estrone being the predominant estrogen species. Conjugated hormones were detected only at low levels. The isoflavone metabolite equol was by far the predominant phytoestrogen species, with daidzein, genistein, formononetin, and coumestrol present at lower levels. Phytoestrogens were often more abundant than steroidal estrogens, but contributed minimally toward total estrogenic activity. Analytes were significantly elevated in the solid phases of the lagoon; although low observed log KOC values suggest enhanced solubility in the aqueous phase, perhaps due to dissolved or colloidal organic carbon. The association with the solid phase, as well as recalcitrance of analytes to anaerobic degradation, results in a markedly elevated load of analytes and estrogenic activity within lagoon sludge. Overall, findings emphasize the importance of adsorption and transformation processes in governing the fate of these compounds in lagoon waste, which is ultimately used for broadcast application as a fertilizer.}, number={23}, journal={ENVIRONMENTAL SCIENCE & TECHNOLOGY}, author={Yost, Erin E. and Meyer, Michael T. and Dietze, Julie E. and Meissner, Benjamin M. and Worley-Davis, Lynn and Williams, C. Michael and Lee, Boknam and Kullman, Seth W.}, year={2013}, month={Dec}, pages={13781–13790} }
 @article{ko_simmons, iii_likirdopulos_worley-davis_williams_sobsey_2010, title={Endotoxin Levels at Swine Farms Using Different Waste Treatment and Management Technologies}, volume={44}, ISSN={0013-936X 1520-5851}, url={http://dx.doi.org/10.1021/es9026024}, DOI={10.1021/es9026024}, abstractNote={Concentrated animal feeding operations (CAFOs) are a major source of airborne endotoxins, which are air pollutants that can cause adverse health effects to both on-site farmers and neighbors. Release of airborne endotoxins to the environment can be reduced using proper waste treatment and management technologies. In this study, the levels of endotoxins released from two swine CAFOs using conventional lagoon-sprayfield technology were compared to those of 15 farms using various alternative waste management technologies in North Carolina. Over a 2-year period, 236 endotoxin samples were collected from the 17 farm units and analyzed using the Limulus amebocyte lysate (LAL) test. Concentrations of airborne endotoxins near barn exhaust fans were significantly higher than at the upwind boundary of the farm and at other farm sites. For most of the study sites, mean concentrations of endotoxins at the downwind boundary of the farm were higher than those at the upwind boundary of the farm, indicating the release of endotoxins from swine CAFOs to the neighboring environment. Endotoxin levels were significantly associated with concentrations of airborne bacteria but not fungi. Environmental factors, such as temperature, relative humidity, and wind velocity, affected the levels of airborne endotoxins at the farms. Based on the ratios of airborne endotoxins in downwind and upwind samples from the farm units, at least five different alternative waste management technologies significantly reduced the release of endotoxins from swine CAFOs. These results suggest that swine CAFOs are important sources of airborne endotoxins, the levels of which can be reduced by applying more robust and effective waste management technologies.}, number={9}, journal={Environmental Science & Technology}, publisher={American Chemical Society (ACS)}, author={Ko, GwangPyo and Simmons, III, Otto D. and Likirdopulos, Christina A. and Worley-Davis, Lynn and Williams, C. M. and Sobsey, Mark D.}, year={2010}, month={May}, pages={3442–3448} }
 @article{ko_simmons iii_likirdopulos_worley-davis_williams_sobsey_2008, title={Investigation of Bioaerosols Released from Swine Farms using Conventional and Alternative Waste Treatment and Management Technologies}, volume={42}, ISSN={0013-936X 1520-5851}, url={http://dx.doi.org/10.1021/es801091t}, DOI={10.1021/es801091t}, abstractNote={Microbial air pollution from concentrated animal feeding operations (CAFOs) has raised concerns about potential public health and environmental impacts. We investigated the levels of bioaerosols released from two swine farms using conventional lagoon-sprayfield technology and ten farms using alternative waste treatment and management technologies in the United States. In total, 424 microbial air samples taken at the 12 CAFOs were analyzed for several indicator and pathogenic microorganisms, including culturable bacteria and fungi, fecal coliform, Escherichia coli, Clostridium perfringens, bacteriophage, and Salmonella. At all of the investigated farms, bacterial concentrations at the downwind boundary were higher than those at the upwind boundary, suggesting that the farms are sources of microbial air contamination. In addition, fecal indicator microorganisms were found more frequently near barns and treatmenttechnology sites than upwind or downwind of the farms. Approximately 4.5% (19/424), 1.2% (5/424), 22.2% (94/424), and 12.3% (53/424) of samples were positive for fecal coliform, E. coli, Clostridium, and total coliphage, respectively. Based on statistical comparison of airborne fecal indicator concentrations at alternative treatment technology farms compared to control farms with conventional technology, three alternative waste treatment technologies appear to perform better at reducing the airborne release of fecal indicator microorganisms during on-farm treatment and management processes. These results demonstrate that airborne microbial contaminants are released from swine farms and pose possible exposure risks to farm workers and nearby neighbors. However, the release of airborne microorganisms appears to decrease significantly through the use of certain alternative waste management and treatment technologies.}, number={23}, journal={Environmental Science & Technology}, publisher={American Chemical Society (ACS)}, author={Ko, GwangPyo and Simmons III, Otto D. and Likirdopulos, Christina A. and Worley-Davis, Lynn and Williams, Mike and Sobsey, Mark D.}, year={2008}, month={Dec}, pages={8849–8857} }