Variability of Anaerobic Animal Waste Lagoon delta¹⁵N Source Signatures

Authors

Sadayappan Mariappan, University of Nebraska–Lincoln
Mary Exner Spalding, University of Nebraska-LincolnFollow
Glen E. Martin, University of Nebraska–Lincoln
Roy F. Spalding, University of Nebraska - LincolnFollow

Date of this Version

2009

Citation

Environmental Forensics 10 (2009), pp. 19–26; doi: 10.1080/15275920802502075

Comments

Copyright © 2009 Taylor & Francis Group. Used by permission.

Abstract

High ammonium-N concentrations derived from animal wastes stored and partially treated in earthen anaerobic lagoons at confined feeding facilities can seep to groundwater. δ¹⁵N-NH₄⁺ values from +2.0 to +59.1‰ in 13 lagoons complicate identification of lagoon seepage as well as land-applied lagoon effluent in ground and surface waters. The spectrum of δ¹⁵N values requires site-specific isotope characterization of the potential source. Feed and fresh manure and urine δ¹⁵N values indicate that most N isotopic fractionation occurs after excretion. Lagoon management clearly affects enrichment. δ¹⁵N-total Kjeldahl N (TKN) and δ¹⁵N-NH₄⁺ within each lagoon were not statistically different. δ¹⁵N-NH₄⁺ within the top 1.5 m of the lagoons was spatially uniform (CV [coefficient of variation] <5%).