M4 PM Endocrine Disruption in Fish (Part 2)
Monday, 14 November 2005: 1:50 PM - 5:30 PM in Ballroom 4

(THE-1117-572188) Thyroid Endocrine Disruption in Stonerollers from Perchlorate-Contaminated Streams in East-Central Texas.

Theodorakis, C¹, Rinchard, J², Kendall, R¹, ¹ Texas Tech University, The Institute of Environmental and Human Health, Lubbock, TX, USA² The Ohio State University, School of Natural Resources, Columbus, OH, USA

ABSTRACT- In October 2001 and March 2002, a field survey of central stonerollers (Campostoma anomalum) from perchlorate-contaminated streams in central Texas was conducted to assess thyroid endocrine disruption. Perchlorate is an oxidizer primarily used in solid-fuel rockets, and many sites that processed or used perchlorate are now contaminated. Histological analysis revealed that the fish from contaminated sites had increased thyroid follicular hyperplasia, hypertrophy, and colloid depletion. Multivariate analysis was generally found to be more powerful than univariate analysis. Seasonal differences existed in the degree of thyroidal perturbation were discovered, and fish were generally less sensitive to thyroidal perturbations in March compared to October. Thyroidal histological indicators were also correlated to levels of perchlorate in the fish, water, and periphyton. Periphyton was frequently most strongly correlated to thyroidal indices, suggesting that exposure through the food chain may be of import. In addition, one of the presumed reference sites turned out to be contaminated with perchlorate, and this was reflected by thyroidal biomarkers before perchlorate was detected in the stream water or biota. This is the first known published account of perchlorate-induced thyroid disruption in fish under field situations, and also points out the value of biomarkers for contaminant biomonitoring.

Key words: Thryoid, Stoneroller, Endocrine, Perchlorate