Low dose effects and non-monotonic dose responses for endocrine active chemicals: Science to practice workshop: Workshop summary

A workshop was held in Berlin September 12–14th 2012 to assess the state of the science of the data supporting low dose effects and non-monotonic dose responses (“low dose hypothesis”) for chemicals with endocrine activity (endocrine disrupting chemicals or EDCs). This workshop consisted of lectures to present the current state of the science of EDC action and also the risk assessment process. These lectures were followed by breakout sessions to integrate scientists from various backgrounds to discuss in an open and unbiased manner the data supporting the “low dose hypothesis”. While no consensus was reached the robust discussions were helpful to inform both basic scientists and risk assessors on all the issues. There were a number of important ideas developed to help continue the discussion and improve communication over the next few years.     

固相微萃取-气相色谱-质谱法测定饮用水中土嗅素和2-甲基异茨醇

采用固相微萃取法富集,气相色谱-质谱联用法定性和定量测定饮用水中致嗅物质土嗅素和2-甲基异茨醇。研究并讨论优化了纤维头的类型、盐的种类和浓度、温度、萃取时间等因素对异味化合物萃取量的影响。土嗅素和2-甲基异茨醇的检出限分别为1.02、2.13 ng/L,相对标准偏差分别为4.96%、7.74%。2种异味化合物在5~1 000 ng/L的范围内线性关系良好,相关系数均大于0.985。因此,用该方法能够很好地分析水中痕量的异味化合物。     

剩余污泥中微生物絮凝剂的提取方法比较

分别采用低浓度和高浓度剩余污泥对剩余污泥中微生物絮凝剂(MBF)的多种提取方法(超声法、树脂法、超声-树脂法、树脂-超声法、超声-树脂-超声法和树脂-超声-树脂法等)进行了比较研究.结果表明,各种复合形式的提取效果均优于超声法或树脂法单独使用的提取效果.在各种复合形式中,以树脂-超声法所提取MBF的含量最高且絮凝效果最好.此外,所提取的MBF浓度与污泥浓度正相关.从剩余污泥中直接提取MBF,在降低MBF生产成本的同时实现了污泥的资源化利用.     

微生物菌剂对好氧填埋垃圾稳定过程的影响

为加速好氧填埋场的稳定化进程,提出利用生物强化技术加速好氧填埋垃圾的生物降解,通过模拟实验,研究了微生物菌剂对填埋垃圾稳定过程的影响。结果表明:微生物菌剂降低了好氧填埋场的有机污染负荷,使渗滤液COD下降更加明显,整个填埋周期所产渗滤液的COD总量较对照组少20.20%;加速了含氮物质的生物转化,氨氮峰值出现较对照组提前6 d,经历峰值以后,氨氮快速下降,较对照组提前22 d达到国家生活垃圾填埋场污染控制标准(GB 16889-2008)所规定的渗滤液氨氮排放标准25 mg/L,并使整个填埋周期氨氮总量减少9.15%;微生物菌剂降低了渗滤液的产量,使整个填埋周期渗滤液累计产量减少8.29%;使垃圾中有机质降解加快并使其降解更加彻底,至实验结束时总有机质含量较对照组低8.82%,干重较对照组减少35.95%;沉降性能优于对照组,至填埋结束时较对照组沉降量提高6.35%。     

生物絮凝剂产生菌群发酵特性及动力学

从土壤中分离、筛选得到2株具有协同发酵的微生物絮凝剂产生菌。通过单因素实验考察了碳源、氮源、不同C/N等多种发酵条件对复合菌株产絮的影响,并对复合菌株的生长动力学进行了研究。当碳源为蔗糖、氮源为草酸铵、C/N为30∶1,pH=7.0、在30℃,160 r/min的摇床速度下培养24 h,其发酵液对4 g/L的高岭土的悬浊液的絮凝率达到99.3%。根据Logistic方程,得到复合型生物絮凝剂产生菌群的生长动力学模型与实验数据能较好地拟合,基本反映了复合菌群生长的动力学特征。     

Geographic variation in tissue accumulation of endocrine disrupting compounds (EDCs) in grazing sheep

Muscle tissue was collected from ewes and lambs derived from farms throughout Scotland and sample concentrations of five endocrine disrupting compound groups were determined. Farms of origin were categorised according to geographic region. There were few statistically-significant differences with region or distance from cities. However, the magnitude of the difference between the highest and lowest mean values in ewe muscle from different regions exceeded 30% for 13 of the 15 compounds that were consistently detected in muscle, with animals derived from the industrialised region having the highest mean values for 11 of the 13 compounds. A less marked trend was apparent in the lamb muscle (8 of 13 highest were in the industrialised region). The physiological effects of such small differences in exposure to mixtures of pollutants remain to be determined.     

新型复合混凝吸附药剂对无铅皮蛋废水的处理

皮蛋废水水质相当复杂,既属于含重金属离子废水,又属于中等浓度含盐有机废水.针对皮蛋废水特点,采用混凝+吸附方法预处理皮蛋废水,将PAC与粉煤灰按2:5的投加比混合复制成一种新型复合混凝吸附剂,通过正交实验考察了复合药剂的较佳处理条件.结果表明,在投加量为5 g/L,pH为6.5左右,搅拌时间约为14 min,处理温度为...     

PTFE乳液涂层对针刺毡复合滤料过滤性能的改良

采用PTFE乳液对P84.PTFE混纺针刺毡复合滤料进行涂层整理,并将其与未经整理的试样进行VDI滤料过滤性能模拟测试,进而阐述PTFE乳液涂层对该复合滤料过滤性能的影响。     

低分子量壳聚糖Nd~(3+)配合物的合成及抑菌性研究

通过将高分子量壳聚糖经双氧水氧化降解制得低分子量壳聚糖,再与Nd3+配位制得低分子量壳聚糖Nd3+配合物,通过IR,UV,TG-TDA和GPC分析对L-CTS的分子量及L-CTS-Nd的结构进行了表征,考察了对金黄色葡萄球菌和大肠杆菌的抑菌性能。结果表明,低分子量壳聚糖与Nd3+形成了稳定的配合物,对金黄色葡萄球菌和大肠杆菌均有良好的抑菌效果。     

Separation and recovery of carbon dioxide by a membrane flash process

A novel process for carbon dioxide (CO₂) separation, which was named a membrane flash process, was developed to realize an energy-saving technology and to substitute it for a conventional regenerator. The electric energy for CO₂ recovery in a membrane flash process using aluminum oxide and diethanolamine was lower than the thermal energy of the conventional chemical absorption process. Flashing at elevated temperature by the low temperature energy significantly reduced the electric energy and required much less membrane area. This process has potentiality of low cost capture of CO₂ when the low temperature energy, which is not available for other purposes, can be utilized to elevate flashing temperature.