title: A Bayesian network model for assessing natural estrogen fate and transport in a swine waste lagoon.
abstract: Commercial swine waste lagoons are regarded as a major reservoir of natural estrogens, which have the potential to produce adverse physiological effects on exposed aquatic organisms and wildlife. However, there remains limited understanding of the complex mechanisms of physical, chemical, and biological processes that govern the fate and transport of natural estrogens within an anaerobic swine lagoon. To improve lagoon management and ultimately help control the offsite transport of these compounds from swine operations, a probabilistic Bayesian network model was developed to assess natural estrogen fate and budget and then compared against data collected from a commercial swine field site. In general, the model was able to describe the estrogen fate and budget in both the slurry and sludge stores within the swine lagoon. Sensitivity analysis within the model demonstrated that the estrogen input loading from the associated barn facility was the most important factor in controlling estrogen concentrations within the lagoon slurry storage, whereas the settling rate was the most significant factor in the lagoon sludge storage. The degradation reactions were shown to be minor in both stores based on prediction of average total estrogen concentrations. Management scenario evaluations demonstrated that the best possible management options to reduce estrogen levels in the lagoon are either to adjust the estrogen input loading from swine barn facilities or to effectively enhance estrogen bonding with suspended solids through the use of organic polymers or inorganic coagulants.
authors.affiliation: Nicholas School of the Environment, Duke University, Durham, North Carolina, USA.
authors.forename: Boknam
authors.initials: B
authors.lastname: Lee
authors.forename: Seth W
authors.initials: SW
authors.lastname: Kullman
authors.forename: Erin
authors.initials: E
authors.lastname: Yost
authors.forename: Michael T
authors.initials: MT
authors.lastname: Meyer
authors.forename: Lynn
authors.initials: L
authors.lastname: Worley-Davis
authors.forename: C Michael
authors.initials: CM
authors.lastname: Williams
authors.forename: Kenneth H
authors.initials: KH
authors.lastname: Reckhow
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D004967:Estrogens / Q000737:chemistry*; D008962:Models, Theoretical; D012722:Sewage / Q000737:chemistry*; D013552:Swine; D014865:Waste Disposal, Fluid; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D004967:Estrogens; D012722:Sewage; D014874:Water Pollutants, Chemical
keywords: Bayesian network model; Estrogen fate and transport model; Natural estrogen hormones; Swine anaerobic lagoon