Survey of hormone activities in municipal biosolids and animal manures

The potential exists for natural or synthetic hormonal chemicals present in agricultural fertilizers to be transferred to adjacent aquatic environments in order to alter endocrine function in exposed wildlife. Recombinant yeast and mammalian cell line (BG1Luc4E2) assays were used to screen crude organic extracts of municipal biosolids and animal manures for estrogen-, androgen-, and progesterone receptor gene transcription activities. Of the biosolid extracts, those samples that had undergone aerobic digestion had no or minimal estrogen- and no androgen receptor gene transcription activities. In contrast, those biosolid samples that had undergone anaerobic digestion had much higher estrogen- and, for all but one site, androgen receptor gene transcription activities. Extracts prepared from animal manure samples had variable levels of androgen- and estrogen receptor gene transcription activities, which may be related to the type, sex, age, and reproductive status of the animals. The diet and treatment of animals with hormone implants also appeared to be factors influencing hormone activity in animal manure. Progesterone receptor gene transcription activity was observed for only one chicken litter sample. Overall, results of this study suggest that in vitro bioassays can be used to survey and detect hormone activity in municipal biosolids and animal manures. Furthermore, results of these assays can be used to develop practices that will minimize the potential environmental endocrine-disrupting effects of these substances.