Estrogenic Contaminant Concentrations and the Incidence of Intersex in Centrarchid Fishes: Landscape-Level Relationships in North Carolina

A multitude of chemicals are demonstrated to mimic estrogens and are linked to adverse effects in fish and wildlife. Male fish, in particular, are susceptible to developing intersex, which is characterized by the presence of testicular oocytes. However, it's unclear which specific estrogenic contaminants play a role in this condition. To investigate the relationship between intersex and exposure to estrogenic contaminants, we conducted a statewide assessment of the occurrence of intersex fish and endocrine disrupting compounds (EDCs) in rivers and streams throughout North Carolina. We targeted two genera in the Centrarchidae family: black bass (Micropterus) and sunfish (Lepomis), which were sampled from 20 sites throughout the state. Histopathology was conducted on testicular cross sections to assess intersex. To measure the levels of EDCs, passive sampling devices were deployed and sediment samples were collected for quantification of steroidal hormones, industrial compounds, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, legacy organochlorine pesticides, and current use pesticides. Intersex was identified in both genera, with the black bass being more susceptible compared to sunfish. Significant relationships between incidence of intersex and several EDCs were detected. This project sheds light on relationships between intersex and contaminant load, as well as differences in responses between two Centrarchidae genera.