Vinitnantharat S, Chartthe W, Pinisakul A
Division of Environmental Technology, School of Energy, Environment and Materials, 126 Pracha-uthit Road, Bangmod, Rasburana, Bangkok 10140, Thailand.
Water Sci Technol. 2008;58(6):1193-8. doi: 10.2166/wst.2008.476.
Textile wastewater normally has a visible color although it has low concentration. This may affect the aquatic ecosystem. Two dyestuffs, Reactive Red 141 (RR141) and Basic Red14 (BR14) were used as compound models. RR 141 is an anionic dye which has a big molecule whereas BR 14 is a cationic dye and has a small molecule. The target organisms for toxicity test were green algae (Chlorella sp.) and waterfleas (Moina macrocopa). The effect of humic acid on the toxicity of dyestuffs to test organisms was also investigated. From the observation of cell counts, Chlorophyll a and dry weight of algae in the dye solutions for 4 days, it was found that all parameters increased as times increased. This revealed that algae could utilize dyestuffs as a carbon source. However, BR14 gave higher absorbance than RR141 at the wavelength of 430 nm which competed to the Chlorophyll a for algal photosynthesis. This resulted in the 96-h EC50 of BR14 and RR141 to Chlorella sp. were 10.88 and 95.55 mg/L, respectively. As for dye toxicity to waterfleas, the 48-h LC50 of BR14 and RR141 to waterfleas were 4.91 and 18.26 mg/L, respectively. The high toxicity of BR14 to waterfleas related to the small molecule of dye could pass into the cell and was absorbed by organelles of waterfleas. Toxicity of BR14 in humic acid solution to Chlorella sp. showed less toxic than RR141 in humic acid solution. This dues to the negative charge of humic acid could bound with a positive charge of BR14, resulted in low amount of BR14 remaining in the bulk solution. The toxicity of BR14 and RR141 in humic acid solution to waterfleas was increased as humic acid increased. Hence, the proper treatment of textile wastewater to yield low concentration of dyes in the effluent before discharging to the natural water is needed.
纺织废水通常浓度较低，但有明显颜色。这可能会影响水生生态系统。选用两种染料，活性红141（RR141）和碱性红14（BR14）作为复合模型。RR141是一种阴离子染料，分子较大，而BR14是一种阳离子染料，分子较小。毒性试验的目标生物是绿藻（小球藻属）和水蚤（大型溞）。还研究了腐殖酸对染料对受试生物毒性的影响。通过对染料溶液中藻类细胞计数、叶绿素a含量和干重进行4天的观察，发现所有参数均随时间增加而增加。这表明藻类可以将染料用作碳源。然而，在430nm波长处，BR14的吸光度高于RR141，它与叶绿素a竞争藻类光合作用。这导致BR14和RR141对小球藻属的96小时半数有效浓度（EC50）分别为10.88mg/L和95.55mg/L。至于染料对水蚤的毒性，BR14和RR141对水蚤的48小时半数致死浓度（LC50）分别为4.91mg/L和18.26mg/L。BR14对水蚤的高毒性与染料小分子可进入细胞并被水蚤细胞器吸收有关。腐殖酸溶液中BR14对小球藻属的毒性低于腐殖酸溶液中RR141的毒性。这是因为腐殖酸的负电荷可与BR14的正电荷结合，导致大量溶液中剩余的BR14量较低。随着腐殖酸含量增加，腐殖酸溶液中BR14和RR141对水蚤的毒性增加。因此，需要对纺织废水进行适当处理，使其排放到天然水体之前，废水中染料浓度较低。
