Androgen Diffusion Patterns in Soil: Potential Watershed Impacts

Androgens are natural or synthetic steroid hormones that control secondary male sex characteristics. Ranchers use FDA-approved androgens to increase livestock growth rates and size. In concentrated animal feeding operations (CAFOs), androgens are excreted in cattle urine and feces. Once excreted, androgens can run off or seep into nearby waters, negatively impacting aquatic life and potentially polluting human water sources. This study aimed to determine the extent to which soil is a barrier to androgen flow, thus protecting waterways. Due to prohibitive costs and purchasing regulations of androgens, luminol, a chemical analogous to androgens in both polarity and organic makeup, was used to mimic androgen diffusion patterns. We formulated two hypotheses: first, that soil would be a poor barrier to the luminol, and second, that the luminol would have a greater vertical diffusion than horizontal diffusion. Diluted luminol was added to soil plots and the diffusion was measured by analyzing soil plot layers. We extracted moisture from the soil layers and used a Woods lamp to detect luminol, which diffused up to 22.5 cm vertically and 26 cm horizontally. Diffusion patterns indicated that soil was a poor luminol barrier. If androgens reach the soil’s water table, they can potentially diffuse through the local watershed and into the surrounding waterways. This preliminary research indicates the need for further testing of androgen diffusion patterns to ensure the safety of waterways for aquatic life and for human water consumption.