Derivation of an ecological effect-based trigger value for assessment of androgenic activity in water

Androgens, in similarity to estrogens, pose serious threats to aquatic organisms by affecting reproduction and sexual development at concentrations as low as a few ng/L. The adverse effects are mediated via the androgen receptor, which is activated by natural and synthetic androgens, often occurring in complex mixtures. Effect-based monitoring by in vitro bioassay gives a comprehensive view of the total androgenic activity from known and unknown chemicals. For assessment of potential ecological risks from androgens in the aquatic environment an effect-based trigger value (EBT) of 0.4 ng dihydrotestosterone equivalents/L (DHTeq/L) was derived from literature data on reproductive toxicity and determination of relative potencies in AR EcoScreen GR-KO M1 cells of DHT, androstenedione, methyltestosterone and 17β-trenbolone. Androgenic activity was determined in 782 samples of various water types collected in Sweden and the activities were compared with the derived ecological EBT. Androgenic activity was above EBT in almost all wastewater influents. Despite a treatment removal efficiency of 79-100%, androgenic activity was above EBT in 16% of effluents, 5% of recipients and 8% of surface water samples. This may be an underestimation as there is a risk of false negative results in samples where LOD is exceeding the EBT. Maximum androgenic activities in recipients, surface and raw water samples were 26.4, 11.2 and 3.27 ng DHTeq/L, respectively. Literature data show androgenic activities within the same order of magnitude as in the Swedish samples. Mainly unknown chemicals contribute to the androgenic effects in water, which clearly shows the need of effect-based methods and an EBT for environmental monitoring and assessment of androgenic effects.