Incorporation of 17-β Estradiol and Testosterone From Broiler Litter Into Soil Organic Matter.

The presence of reproductive hormones in the environment is of concern because they may adversely affect vertebrates. Landspreading broiler litter introduces these hormones into the environment and is especially important in Georgia because the State leads the United States in broiler litter production.  We determined the effect of two water potentials (-1.5 and -0.03 MPa) and two temperatures (10 and 30°C) on the incorporation of 14C-labeled estradiol and testosterone into the soil organic matter (SOM) fractions of a Cecil sandy loam.  After the hormones (mixed with broiler litter) mineralized for 6 months on the soil surface, SOM fractions were extracted and analyzed with liquid scintillation and biological oxidation.  Higher temperature and higher water potential (closer to zero) generally resulted in decreased percentages of estradiol and testosterone found in water- and acetone-soluble soil fractions and an increased percentage in SOM.  However, the distribution of the two hormones in SOM differed. Generally for estradiol, higher temperature and higher water potential increased the percentage of hormone in fulvic acid; for testosterone, higher temperature and higher water potential generally increased the percentage of hormone found in humin, and fulvic and humic acids. The results suggest that, presumably within certain limits, the biological activity necessary to incorporate the two hormones into SOM is greater at higher temperature and higher water potential.  More importantly, these results suggest that estradiol and testosterone become incorporated into SOM, and this incorporation may account for the observed decreased mineralization of the two hormones after 6 months (estradiol 11% at -0.03MPa and 30°C; testosterone 43% at -0.03 MPa and 30°C).  Because the SOM results only reflect sampling at one time (6 months), experiments are in progress to determine the rate of incorporation of these two hormones into the SOM over time.