Occurrence and some properties of the androgenic activity in municipal sewage effluents.

Androgenicity was tested in municipal effluents before and after treatment in sewage treatment plants using different treatment methods. The activity was tested with a recombinant yeast strain transfected with the gene for the human androgen receptor. Fractionation of effluents showed some basic properties of compounds with androgenic activity. Effluents from Swedish domestic sewage treatment plants contained compounds with androgenic effects. Levels varied from 0-160 ng dihydrotestosterone (DHT) equivalents/L. The androgenicity was higher in untreated effluents and removals of 26 and 42% for STWs without secondary treatment and 96- > 99% were recorded for STWs with secondary and tertiary treatment. As with estrogens in municipal effluents, STWs using biological treatment such as activated sludge and solid supported microbial processes were more effective in reduction of androgenic activity. Plants using only precipitation methods removed less of the activity. The androgens were composed of at least three individual compounds, similarly or less lipophilic than DHT.