Oestrogens and anti-androgens in the aquatic environment and their effects on fish

Abstract

Endocrine disrupting chemicals (EDCs) can enter the aquatic environment via wastewater treatment work (WwTW) effluents. Oestrogenic and (anti-)androgenic chemicals present in effluents affect the reproductive health of fish living downstream of these effluents. The effects of WwTW effluent before and after the addition of an advanced granular activated carbon (GAC) treatment; installed to reduce EDCs, are compared. In laboratory studies, no oestrogenic effects of standard or GAC effluent were observed in fathead minnows (FHM; Pimephales promelas). However, the standard effluent elicited possible anti-androgenic effects not observed in the GAC-treated effluent. In the river receiving this effluent, wild roach (Rutilus rutilus) were sampled before and after the GAC addition. Here oestrogenic effects were observed in the roach, and these effects were reduced following the GAC addition to the WwTW, but not completely removed. Over 100 chemicals previously detected in WwTW effluents were examined for (anti-)androgenic activity using an in vitro yeast-based assay. Toxicity can cause false positive results in this assay. Investigations, including employing a modified version of the in vitro assay, were conducted to improve the assay’s reliability. Then, assessments of the most potent anti-androgenic chemicals were made to determine if they were likely to cause a risk to the environment. Currently, the best in vivo fish screen for (anti-)androgenic activity utilises the induction of spiggin, an androgen dependent glue-like protein, normally produced by male 3-spined stickleback (Gasterosteus aculeatus) during nest building. Male FHMs also glue their mates’ eggs to substrate. Therefore, FHM may have homologous androgen dependant genes/proteins which could serve as biomarkers of (anti-)androgenic activity. Spiggin-like primers were designed and used to look for spiggin-like genes in tissues collected from FHM. However, none of the spiggin-like primers were male specific and further work is needed to determine if similar androgen dependant spiggin-like proteins are present in FHM.