Biotransformation and detoxification responses to the exposure to five polycyclic aromatic hydrocarbons were investigated in crucian（Carassius auratus）. Juvenile crucian were treated with a single intraperitoneal injection of each compound at dosages of 0.1, 1.0, 2.0, 5.0 and 8.0（or 10.0） mg/kg and sacrificed 15 d later to determine 7-ethoxyresorufin-O-deethylase（EROD） and glutathione S-transferases（GST） activities in gill S9 fractions. EROD activity is significantly increased by benzo（b）fluoranthene and indeno（1,2,3-cd）pyrene at all the doses. High dosages of PAHs induced GST activity and the inducing ability of them increased in the following order： fluorene fluorantheneindeno（1,2,3-cd）pyrenebenzo（g,h,i）perylenebenzo（b）fluoranthene. In all the cases, dose dependence appeared to exist. The gill EROD and GST in Carassius auratus are useful biomarkers to estimate sub-acute toxicity of both polycyclic aromatic hydrocarbons（PAHs） and PAHs-like compounds.
Objective To study the biological effects of nanoscale copper oxide （nCuO）, zinc oxide （nZnO）, cerium dioxide （nCeO2） and their mixtures on Carassius auratus. Methods Juvenile fish （Carossius auratus） were exposed to aqueous suspensions of nCuO, nZnO, and nCeO2 （alone and in mixtures） at concentrations of 20, 40, 80, 3.60, and 320 mg/L. The biomarkers-acetylcholinesterase （ACHE） in brain, sodium/potassium-activated ATPase （Na~/K＊-ATPase） in gill, and superoxide dismutase （SOD） and catalase （CAT） in liver-were determined after 4 days of exposure. Integrated biomarker response （IBR） was calculated by combining multiple biomarkers into a single value. Results AChE and SOD activities were significantly inhibited by all test metal oxide nanoparticles （NPs） at high concentrations （__.160 rag/L） with the exception of nCeO2. Na~/K＋-ATPase induction exhibited bell-shaped concentration-response curves. CAT activity was significantly inhibited at concentrations equal to or higher than 160 mg/L. The order of IBR values was nCeO2 = nZnO/nCeO2= nCuO/nCeO2 〈 nCuO/nZnO/nCeO2 〈 nZnO 〈 nCuO 〈 nCuO/nZnO. The joint effect seemed to be synergistic for nCuO/nZnO mixtures, additive for the ternary mixture and less than additive or antagonistic for the binary mixtures containing nCe02. Conclusion Concentration-dependent changes of enzymatic activities （ACHE, Na~/K＊-ATPase, SOD, and CAT） were observed in fish exposed to nanoscale metal oxides. IBR analysis allowed good discrimination between the different exposures and might be a useful tool for the quantification of integrated negative effects induced by NPs toward fish.
Effects of river water from the Yangtze River （Nanjing section） on fish development, vitellogenin （VTG） induction, gonado-somatic index （GSI） and sex ratio were investigated by exposing goldfish （Carassius auratus） in the early life stage （from fertilization to 28 days post-hatch） to water samples （25%, 50% and 100%） collected from three representative sections. The results showed that there was no significant effect on hatching success for any of the exposure groups, but survival was significantly reduced when compared with the control （P 0.05）. Body lengths, weights of all treated fish did not differ significantly from those of the control. Condition factors （CF） of larval fish exposed to 50% and 100% river water from the Jiangxinzhou section and 100% river water from the Daqiao section were significantly lower than that of the control （P 0.05）. VTG inductions were significant in larval fish exposed to all the dilution series of river water. No significant difference in CF value was observed in any exposure group after 150 days of depuration. VTG was fully eliminated after 75 days of depuration. For both female and male, GSI did not significantly differ between exposure groups and the control after 150 days of convalescence. The highest female：male ratios were observed in response to the treatment with 50% or 100% river water from the Jiangxinzhou section and 100% river water from the Daqiao section （53：47, 56：44 and 54：46, respectively）, but no significant difference in sex ratio was observed in any treated group when compared to the control. The results showed that early life stage exposure of river water from the Yangtze River （Nanjing section） had adverse effects on goldfish development and reproductive health, and the effects on CF and VTG were reversible after depuration in clean water.
