Location: Animal Metabolism-Agricultural Chemicals ResearchTitle: Estrogenic activity, estrogens, and calcium in runoff post-layer litter application from rainfall simulated events
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/12/2017
Publication Date: 11/12/2017
Citation: Shappell, N.W., Shipitalo, M.J., Billey, L.O. 2017. Estrogenic activity, estrogens, and calcium in runoff post-layer litter application from rainfall simulated events [abstract]. 38th Annual Society of Environmental Toxicology and Chemistry North American Mtg., November 12-16, Minneapolis, MN. Abstract #547. p. 134.
Interpretive Summary: .
Technical Abstract: Estrogens in runoff from fields fertilized with animal wastes have been implicated as endocrine disruptors of fish in recipient surface waters. The goal of this study was to measure estrogenic activity in runoff post-application of animal waste with the greatest potential for estrogenic activity - fresh litter from caged laying hens. Litter was applied and tilled into six 0.0045 ha plots. Six paired control plots (no hen litter) were also tilled. The next day, 65 mm hr-1 rainfall simulations were performed and runoff was collected from treated plots 10, 15, 20 and 30 min after the start of runoff, and composite runoff samples of the total event were taken from control and treated plots. Simulated rainfalls at the same intensity were repeated 1 and 3 wks after the initial event. Samples were analyzed for estrogenic activity (E-Screen), estrogens, calcium (Ca), coliforms, and E.coli. Previous work indicated a possible correlation between Ca and estradiol equivalents (E2Eq) in runoff. The maximum E2Eq never exceeded 3 ng/L and decreased to = 0.1 ng/L by week 3. In contrast, mean soluble Ca increased across weeks from 18 to 46 mg/L in treated plots (controls 14 to 15 mg/L). Because peak E2Eq and Ca were not concomitant, Ca would not be a useful surrogate for indicating the presence of E2Eq in runoff post-layer litter application. Soil moisture influenced coliform number. Drier plots had lower coliform numbers, though variability among plots was extreme (37-fold for controls and 25-fold for treated). Similarly, E.coli numbers were related to soil moisture, with the highest counts in week 3 runoff in 4 of 6 plots. While ß-E2 was present in litter, no ß-E2 was detected in runoff. Maximum 17a-E2 and estrone concentration in runoff was ~ 3 and 14 ng/L respectively, lower than concentrations documented to induce vitellogenin in fathead minnows. Our results indicate runoff post-application of composted layer litter should not cause estrogenic endocrine disruption, as concentrations post-application of “fresh” litter were lower than necessary to elicit disruption.