Abiotic Transformation of Hormones Catalyzed by Fe(III)-Montmorillonite and Nitrite.

Natural and synthetic hormones associated with manure from concentrated animal feeding operations are of concern for both surface and groundwater quality due to their continuous input to the environment. Once hormones enter the environment in receiving waters and soils they are subject to both biotic and abiotic transformation. Limited information on how hormones degrade in the environment is available, as are the identity and persistence of environmental degradation products. The objective of this study was to investigate abiotic hormone transformation in the presence of Fe(III)-saturated montmorillonite and nitrite. In our study, 17β-estradiol and its glucuronide and sulfate conjugates were incubated with Fe(III)-saturated clay at different concentrations for up to 10 days. Transformation products of target compounds were characterized using HPLC/MS/MS and quantified using HPLC/UV. Our results showed that within 2 hours more than 95% of hormones were rapidly transformed with the presence  of Fe(III)-montmorillonite and nitrite, while no transformation was observed in montmorillonite only system. With the presence of Fe(III)-montmorillonite some hormones were polymerized into dimer and trimer, while addition of nitrite to the system further increased hormone transformation process.