Pb2+、Cd2+和Cr(Ⅵ)抑制球形红细菌生长的毒性效应

运用评价化学品对水生生物毒性的标准方法,得到Pb2 、Cd2 和Cr(Ⅵ)对球形红细菌生长的最小无差异浓度(LNOEC)分别为85.9mgL-1、22.1mgL-1和17.7mgL-1.根据实验结果采用几率单位进行数据处理,得到抑制球形红细菌生长的96hEC50分别为195.0mgL-1、91.2mgL-1和77.6mgL-1,并对各剂量反应方程进行χ2检验,结果均符合精度要求,计算出的96hEC50真实可靠.研究结果表明,抑制球形红细菌生长的毒性由大到小的顺序是Cr(Ⅵ)>Cd2 >Pb2 .不同金属离子与细胞壁亲和性不同或能通过菌体内生物化学转化形成沉淀,可能是导致金属离子抑制球形红细菌生长毒性差异的主要原因.图1表2参15     

PAC-MBR处理垃圾渗滤液的硝化性能研究

研究了粉末活性炭(PAC)作为载体的膜生物反应器(MBR)处理吹脱后垃圾渗滤液的硝化性能.在HRT=3 d、NH 4-N=200～500 mg/L条件下,进水pH＞8.7时,PAC-MBR和没有添加PAC的普通MBR均只能将氨氮转化为NO-2;降低pH至7.6～8.2时,PAC-MBR中的亚硝酸盐氧化菌迅速恢复活性,将NO-2完全转化为硝酸盐,而普通MBR仍然停留在亚硝化阶段;当吹脱取消后,NO-2迅速消失,这可能与取消吹脱后,不再使用大量硫酸进行pH调节有关.研究发现,当SO2-4为3 g/L时,氨氮氧化速度出现了明显的下降,表明SO2-4对硝化菌具有抑制作用;同时,微生物代谢产物(SMP)分泌量越高,NO-2含量越低,但是SMP不是影响NO-2积累的主要原因.     

Use of subsampled traffic data to estimate roadway emissions, including conversion to MOBILE6 vehicle classifications

Air quality is degraded by many factors, among which the emissions from on-road vehicles play a significant role. Timely and accurate estimate of such emissions becomes very important for policy-making and effective control measures. However, lack of traffic data and outdated emission software make this task difficult. This research has demonstrated a new method that facilitates the vehicular emission inventories at the local level by using shorter-time Highway Performance Monitoring System (HPMS) traffic data along with the latest U.S. Environment Protection Agency (EPA) emission modeling software, MOBILE6. The conversion methodology was developed for converting readily available HPMS traffic volume data into EPA MOBILE-based traffic classifications, and a corresponding software program was written for automating the process. EPA MOBILE6 model was used to obtain emissions of nitrogen oxides (NOx), volatile organic compound (VOC), and cabon monoxide (CO) emitted by the parent traffic and subsampled traffic data, and these emissions were additionally compared. The case study has shown that the difference of the magnitude between the emission estimates produced by certain subsampled and parent traffic data are minor, indicating that subsampled HPMS data can be used for reporting parent traffic emissions. It was also observed that traffic emissions follow a Weibull distribution, and NOx emissions were more sensitive to the traffic data composition than VOC and CO. Lastly, use of average emission values of 20 or 30 consecutive minutes appears to be valid for representing hourly emissions.     

Distribution of organochlorine pesticides in seawater of the Bering and Chukchi Sea.

Organochlorine pesticides (OCPs) in the seawater collected in the Bering and Chukchi Seas during the First Chinese Arctic Research Expedition were confirmed by gas chromatography-mass spectrometry (GC-MS) and analyzed by capillary gas chromatography with micro-electron capture detector (GC-microECD). The average of hexachlorocyclohexanes (HCHs; sum of isomers alpha-, beta-, gamma-, delta-) was nearly equal in the Bering Sea (mean concentration 412.7 pg/l) and in the Chukchi Sea (mean concentration 445.8 pg/l), which showed no obvious latitudinal difference of these two regions. Compared with previously reported studies, concentrations of OCPs in these regions were much lower than the levels in the last decades. The ratio of alpha:gamma HCH was 5.0 and 3.4 for the Bering and Chukchi sea, respectively, which indicated the different pesticide composition in these two regions. Many other OCPs with different residue patterns were also found for the first time in the investigation regions. Heptachlor epoxide (in the Bering Sea) and heptachlor (in the Chukchi Sea) were main OCPs contaminants besides HCHs.     

甘蔗糖蜜酒精废液色素特性及脱除的研究

定性地分析了甘蔗糖蜜酒精废液色素的主要成分，并对其颜色特征及稳定性进行了深入的研究，通过对离子交换树脂，吸附树脂和活性炭等的脱色试验比较，筛选出较理想的脱色剂－－粉状活性炭，并得出了相应的脱色工艺参数，脱色率达１００％。     

Trace analysis of dissolved polychlorinated organic compounds in the water of the Yangtse River (Nanjing, China)

Eighteen organochlorine contaminants from the water samples of the Yangtse River have been qualitatively and quantitatively analyzed. The analysis of polychlorinated organic compounds (PCOCs) extracted by C18 Solid Phase Extract (SPE) was performed using HP6890 gas chromatograph coupled by ECD detector. The analytical results demonstrate that the analytical methods are reliable based on the fact that most of the recoveries for the targeted compounds are 60-90%. Most of the concerned contaminants, i.e. chlorinated pesticides and PCBs were found in the water samples of the Yangtse River, but their concentration was very low, <2.97 ng l(-1), which is far less than 1 microg l(-1)--the standard of drinking water of China. It is apparent that the PCOCs were in high concentration during the dry season, and in low concentration during the rainy season. The situation of PCOCs contamination in the water of the Yangtse River in 1999 was greatly improved in comparison with 10 years ago.     

修复受污染水体的潜流人工湿地微生物多样性研究

进行了潜流人工湿地修复受污染水体试验研究,并比较单一植物与单一填料系统与多种植物系统与多种填料系统的处理效果.运用PCR-DGGE技术研究3种不同类型的潜流人工湿地中微生物种群结构,结合多样性分析和聚类分析方法,分析了人工湿地微生物种群结构特征.     

离子交换树脂及其在废水处理中的应用

介绍了离子交换树脂及其在多种废水处理中的应用研究。离子交换树脂法处理废水具有可深度净化、处理效率高和能实现多种金属综合回收的优点，在水处理领域必将得到更为深入的应用。     

磷酸铵镁沉淀法脱氨机理、应用及沉淀剂循环

铵根离子可以和镁盐、磷酸根在适当的条件下生成磷酸铵镁沉淀，利用这一反应可以去除水中的氨氮。本文从磷酸铵镁的性质、反应机理、反应条件及沉淀剂循环利用等方面，对这一方法进行了介绍和总结，并对今后该技术发展提出了建议。