Serum Estrogenicity and Biological Responses in African Catfish Raised By Wastewater Aquaculture in Ghana.

Sustainable food production systems including wastewater-fed aquaculture which promote efficient water use are becoming popular globally. However, the potential effects of wastewater-borne growth and reproduction modulating compounds including estrogens pose new challenges that need to be addressed. We examined the biological effects of wastewater-borne estrogens on African catfish (Clarias gariepinus) raised in a wastewater stabilization pond (WSP) of a functioning municipal wastewater treatment plant, a wastewater polishing holding pond (WWP) of a dysfunctional treatment plant, and a reference pond (RP) unimpacted by wastewater, all located in Ghana (West Africa). Estrogen concentrations in pond water were measured by liquid chromatography/tandem mass spectrometry. Results showed mean 17 ß-estradiol and estrone concentrations were higher in the wastewater ponds (WSP and WWP) than the reference. Fish serum assayed by E-SCREEN showed significantly higher estrogenicity in female vs. male catfish in the RP and WSP but not in the WWP (p ≤ 0.05). Histological examination of liver and gonad tissues showed no apparent signs of intersex or pathology. Similarities  in various measures of body indices were observed between fish of this study and African catfish raised in other freshwater systems. Biological metrics in this study suggest that aquacultural use of adequately treated municipal wastewater had minimal estrogenic effects on African catfish. Investigation of other growth and reproduction-modulating compounds (e.g. androgens) is warranted.