Submitted to: Environmental Science and Technology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/12/2003
Publication Date: 9/1/2004
Citation: Casey, F., Larsen, G.L., Hakk, H., Simunek, J. 2004. Fate and transport of testosterone in agricultural soils. Environmental Science and Technology 38:790-798. Interpretive Summary: Over the past several years, there has been an increase in concern regarding reproductive hormones in the environment. To date, there exists limited research on the fate and transport of these chemicals in the environment. In this study, a series of laboratory soil/hormone interaction and soil column experiments were conducted using the male hormone testosterone. Testosterone concentrations that were used were similar to those found in manures that were applied to field soils. In the soil/testosterone interaction experiments it was shown that the absorption of the hormone to the soil was effected by the soil particle size and the amount of soil organic matter. The soil appeared to break down testosterone rapidly as it interacted with the soil. Although it was found to be degraded more readily than estradiol, it appeared to have a greater potential of migration through the soil because it is not as strongly absorbed. This study underlined the importance of the simultaneous movement, degradation, and interaction of the hormone as it moves through the soil.
Technical Abstract: Hormones excreted in animal waste have been measured in surface and groundwater associated with manure that is applied to the land surface. No studies have been done on the fate and transport of androgenic hormones in soils. In this study, batch and column experiments were used to identify the fate and transport of radiolabeled [14C] testosterone in agricultural soils. The batch results indicate that sorption kinetics change through time, where initial (0 h < t = 1 h) first-order sorption was very rapid (w = 1.81 - 5.58 h-1) followed by a second stage (1 h< t = 168 h) of slow sorption (w = 9´10-5 - 0.32 h-1). There were weak correlations of sorption with soil particle size and organic matter, which indicated a sorption relationship to the amount of surface area present and perhaps clay type. Testosterone was present in all the soil column effluents and a fully kinetic-sorption, chemical non-equilibrium model was used to describe the data. Column experiment sorption estimates were lower than the batch, which resulted from rate-limiting sorption due to the advective transport. The column degradation coefficients (0.404 ' 0.600 h-1) were generally higher than values reported in the literature for 17b-estradiol. Although it was found that testosterone degraded more readily than 17b-estradiol, it appeared to have a greater potential of migration through the soil because it is not as strongly sorbed. This study underlined the importance of the simultaneous transformation and sorption processes in the fate and transport of hormones.