丁香菌酯对平突船卵溞的毒性效应

丁香菌酯是中国自主研发的甲氧基丙烯酸酯类杀菌剂,为明确其对水生生物的毒性,本研究采用半静态试验法,分别检测了丁香菌酯对平突船卵溞的急性和慢性毒性。急性毒性试验结果表明,丁香菌酯对平突船卵溞的48 h-EC50值为202μg/L,属于高毒;慢性毒性试验结果表明,丁香菌酯对平突船卵溞初次产溞时间、产胎数、单雌产溞数及21 d体长等指标均有显著影响,对初次产溞数和蜕壳数影响不显著,以繁殖量为指标,其无可观察效应浓度(NOEC)为0.22μg/L,最低可观察效应浓度(LOEC)为0.67μg/L。研究表明,丁香菌酯胁迫对平突船卵溞的生长和繁殖有一定的抑制效应。该结果可为合理评价丁香菌酯对水生生态系统的风险提供参考。

Comparative experimental investigation of chemical grouting into a fracture with flowing and static water

We present a series of experimental tests on chemical grouting into a fracture with flowing and static water,using a transparent fracture grouting experimental device.Variations of seepage pressure and grout propagation were compared in our investigation.The results show that flowing water results in drops of seepage pressure,development of penetration radii in the upstream side and drops of propagation area during the same period,compared with grouting in static water.The propagation area in static water is always round before grouts reach the joint boundaries.However,the propagation shape changes from round to an elliptic shape for grouting into a fracture with flowing water.A theoretical model for the grout penetration radius in a fracture considering flowing velocity was developed and validated by our experimental results.These results are helpful in improving understanding of fracture grouting mechanism and in guiding engineering practices.

2,2',4,4'-四溴联苯醚胁迫对尼罗罗非鱼肝脏抗氧化防御系统的影响

为探索四溴联苯醚对鱼类抗氧化防御系统的毒性效应及其对鱼类健康的潜在危害,采用半静态水质接触染毒法,设置5、50和500μg·L^(-1)3个暴露浓度,1、3、7、15和30 d5个采样时间,研究了BDE-47对罗非鱼肝脏抗氧化防御系统的影响。结果表明:BDE-47暴露下罗非鱼肝脏抗氧化酶活性或抗氧化因子含量发生了显著变化,显示出BDE-47暴露可引起生物体产生氧化应激并造成氧化损伤;从罗非鱼肝脏抗氧化酶对BDE-47暴露的响应情况来看,SOD、CAT和GSH是相对敏感的抗氧化指标;BDE-47暴露浓度与罗非鱼肝脏SOD、CAT、GST和GPx活性以及GSH和GSSG含量之间没有明显的剂量-效应或时间-效应关系;总体来看,CAT和GSH呈现出先升高后降低的变化趋势;GST和GPx呈现出先升高后降低并恢复至正常水平的变化趋势;GSSG呈现出升高趋势;SOD在低浓度BDE-47(5μg·L^(-1))暴露下表现为先升高后降低的变化趋势,在高浓度BDE-47(50和500μg·L^(-1))暴露下表现为先降低后升高的变化趋势。