integrated biomarker responses of carassius auratus exposed to bde-47, bde-99 and their mixtures

polybrominated diphenyl ethers (pbdes) have been widely used in many products as flameretardants, which resulted in their release into the environment. little is known about the impact of coexisting pbdes on organisms. in this study, the in vivo effects of bde-47 and bde-99 on a suite of biomarkers, acetyl cholinesterase (ache), ethoxyresorufin-o-deethylase (erod), glutathione-s-transferase (gst), superoxide dismutase (sod) and catalase (cat), in goldfish (carassius auratus) were investigated. the enzyme activities were significantly altered by the two pbdes (alone and in combination) after 2, 4, and 7 days of exposure, and obvious dose-response and time-response relationships were observed at most cases. the results suggest that these biomarkers could be used to assess ecological risks of pbdes on fish. an integrated biomarker response (ibr) was calculated by combining multiple biomarkers to single value and used to quantitatively evaluate the toxicological effects of different chemicals. in general, bde-99 showed more adverse biological effects than bde-47. the joint action of mixtures seemed to be synergism at low dosage and antagonism at high dosage with regard to ibr variation.