Preliminary observations on the effect of octylphenol exposure on sex differentiation in the cichlid fish Cichlasoma dimerus (Teleostei, Perciformes).

F. MEIJIDE, F. LO NOSTRO, Y. PIAZZA, A. CALABRÓ LÓPEZ, G. REY VÁZQUEZ, G. GUERRERO

Buenos Aires, Argentina

Congreso; VI Congreso SETAC Latinoamérica; 2003

SETAC Latinoamérica. Society of Environmental Toxicology and Chemistry

It is becoming evident that an increasing number of widely used industrial and agricultural chemicals are estrogenic. Alkylphenols such as octhyphenol (OP) and related compounds are biodegradation products of alkylphenol polyethoxylates, a group of nonionic surfactants used in detergents, paints, pesticides and cosmetics. These chemicals are widespread aquatic pollutants and bioconcentrate in the aquatic biota. However, the physiological consequences of exposure of wildlife and humans to these compounds are not completely known. Since sexual differentiation in fish is determined by the hormonal environment at a critical period during larval development, exposure to environmental estrogens could affect this process. In the present study, we analize the effect of OP exposure on C. dimerus sex differentiation. 30 day-old larvae were exposed to nominal concentrations of 1, 10 and 100 mg/l OP for 2 months, under semi-static conditions. Fishes were sacrified at the end of the experiment, sexed under a stereomicroscope and processed for histology. In treatments with 10 and 100 mg/l, sex ratios were significantly skewed towards females, while no significant deviation from the expected 1:1 proportion was observed with 1 mg/l. Histological examination revealed no differences in gonadal tissues between control and treated fish.