To evaluate impact of printing-dyeing wastewater on aquatic ecological systems, an experiment was carried out using Scenedesmus obliquus, Daphnia magna and Hemibarbus maculates as subjects for test of toxicity of printing-dyeing wastewater. In the experiment the wastewater was diluted with 7346 - 2 standard diluent into solutions different in concentration, I. E 100. 00% , 50. 00% , 25. 00% , 12. 50% , and 6. 25% . Results show that the wastewater was somewhat toxic to all the three kinds of aquatic organisms in the aquatic ecosystem regardless of its nutrient level. The 24 and 48 h-EC50 (effective concentration for reduction of growth by 50%) of the wastewater was (51.55 ±4. 12)% and (20.40 ± 6. 27)% , respectively, to S. Obliquus, and (78. 20 ±4. 31)% and (53. 10 ± 1. 88)% , respectively, to D. Magna. The 96h-LC50 of the wastewater to cleavage stage, blastula stage, gastrula stage, lava, and 25-day fingerlings of//, maculates was (19. 89 ±1.68)% , (25. 95 ±2. 14)% , (27. 24 ±0. 88)% , (19.61±2.21)%, and (49. 27 ±3. 27)% , respectively. The safe concentration of the wastewater to aquatic organisms was 1. 96% . So, discharge of such wastewater should be strictly controlled in practice.%为合理评估印染废水对水环境造成的影响,以斜生栅藻(Scenedesmus obliquus)、大型溞(Daphnia magna)和太湖花(鱼骨)(Hemibarbus maculates)为受试生物,印染废水分别用标准稀释液7346-2按照几何级数稀释成为100.00％、50.00％、25.00％、12.50％和6.25％的系列试验液,研究印染废水对3种水生生物的毒性效应.结果表明,印染废水对水生态系统中不同营养层次的3种生物均有一定的毒性,对斜生栅藻24、48h的半数生长抑制浓度(EC50)分别为(51.55±4.12)％、(20.40±6.27)％,对大型溞24、48h的EC50分别为(78.20±4.31)％、(53.10±1.88)％,对花(鱼骨)卵裂期胚胎、囊胚期胚胎、原肠期胚胎、初孵仔鱼和25日龄仔鱼96h的半数致死浓度(LC50)分别为(19.89±1.68)％、(25.95±2.14)％、(27.24±0.88)％、(19.61±2.21)％和(49.27±3.27)％.研究得出印染废水对水生生物的安全浓度为1.96％,生产中应严格控制其排放.
展开▼
