城市黑臭水体整治前后上覆水和孔隙水的生物毒性对比和评价

以常州市典型城市黑臭水体神童浜为对象,采用小球藻和大型溞作为急性毒性测试手段,对整治前、后神童浜4个点位的上覆水和孔隙水的毒性效应进行了对比和评价。结果表明,整治后神童浜上覆水水质明显改善;上覆水在整治前、后对小球藻生长均无抑制作用,反而呈促进作用;对黑臭水体的整治降低了上覆水和孔隙水的生物毒性,但整治后的上覆水仍存在富营养化问题,且孔隙水对水生生物仍具有一定的毒性风险。提出,利用生物毒性测试能反映出黑臭水体整治前、后的毒性变化,可应用于对黑臭水体整治效果的评价。     

Treatment of fracturing fluid waste by Fenton reaction using transition metal complexes catalyzes oxidation of hydroxypropyl guar gum at high pH

Environmental Chemistry Letters - Hydroxypropyl guar gum (HPGG), polyacrylamide (PAM) and carboxymethyl cellulose (CMC) are widely used as thickeners in...     

Copeland法与证据权重法在污染物危害性排序上的对比研究

化学物质可能对生态环境或通过不同环境介质对人体健康造成危害。为识别出高危害的污染物,采用Copeland计分排序法和证据权重法,分别选择4、6和8个筛选指标,开展了50种污染物危害特性优先性排序。结果表明:筛选因子数量相同时,2种方法危害性排序结果的斯皮尔曼相关性在0.94以上,具有较好的相关性,可见2种方法均可用于污染物危害性排序;方法相同时,不同指标排序结果之间的相关性相对较小,表明选择不同的筛选指标对结果影响较大。     

阳离子型聚丙烯酰胺絮凝剂的开发与煤气化黑水处理

煤气化过程产生的黑水通常采用絮凝处理去除悬浮物及部分有机物后循环使用。以丙烯酰氧乙基三甲基氯化铵为阳离子单体,以氧化还原类和偶氮类引发剂为复合引发剂,采用水溶液自由基共聚法制备了一种适用于黑水絮凝处理的阳离子型聚丙烯酰胺。实验结果表明：引发温度为15~20 ℃时,聚合反应较为平稳,1 h后聚合反应结束,于60~80 ℃干燥,得到产品相对分子质量较高,达（734~1 086）×10⁴;采用该絮凝剂絮凝处理黑水时,絮体大、沉降速率快,絮凝沉降效果佳;在煤气化装置黑水工况温度下,絮凝剂投加量为3 mg/L时,黑水中悬浮物质量浓度可从114 mg/L降至30 mg/L以下,满足现场使用要求。     

用沸石吸附稀土冶炼氯铵废水中的氨氮

用天然沸石对稀土冶炼氯铵废水中的氨氮进行吸附实验。通过实验得到的最佳工艺条件为：废水pH7—8、沸石粒径0．5—1．0mm、沸石投加量60g；先以300r／min搅拌1min，再以60r／min搅拌30min，沉降30min。稀土冶炼氯铵废水经沸石吸附处理后，废水中的氨氮质量浓度由13013mg／L降至6168mg／L，氨氮去除率达52．6％。     

Comparison of atrazine losses in three small headwater catchments

Understanding the processes causing herbicide transport to surface waters is crucial to determine mitigation options to reduce these losses. To this end, we investigated the atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) transport in three agricultural catchments (1.1-2.1 km2) in the watershed of Lake "Greifensee" (Switzerland). In 1999, atrazine application data were recorded for all three catchments. Time proportional samples were taken at a high temporal resolution at the catchment outlets. Extremely wet conditions caused large relative losses from the catchments, ranging between 0.6 and 3.5% of the amount applied. Most of the atrazine load was due to event-driven diffuse losses from the fields. Farmyard runoff contributed less but caused the highest concentrations (up to 31 microg L(-1)) in the brooks. The maximum concentrations due to diffuse losses varied between 1.2 and 8.2 microg L(-1) among the catchments. Despite different absolute concentration levels, the concentration time-series were very similar. It seems that the travel-times within the catchments were mainly controlled by the rainfall pattern with little influence of the catchment properties. These properties, however, caused the relative losses to vary by a factor of 6 between the catchments. This variability could be partly explained by differences in the connectivity of the fields to the brooks and by their hydrological soil properties. A comparison of the losses from the three catchments with those from the entire watershed of Lake Greifensee demonstrated that they were representative for the larger area. Hence, the study results provide a good data set to evaluate distributed models predicting herbicide losses.     

汕头市降雨量的概率分布模型

根据汕头市实测的年最大日降雨量资料,采用极值Ⅰ型、极值Ⅱ型、极值Ⅲ型和Ｗｅｉｂｕｌｌ分布等四种极值分布模型模拟,从而确定了年的最大日降雨量的概率模型．并根据年的各时段的最大降雨量仪器记录产生概率模型,建立各时段降雨量之间的相互关系,得到汕头市降雨量的概率分布模型,作为汕头市内涝分析的依据。     

FIELD MEASUREMENT OF FLOW VELOCITIES,SUSPENDED SOLIDS CONCENTRATIONS,AND TEMPERATURES IN LAKE OKEECHOBEE1

ABSTRACT: This paper presents a field investigation of collecting hydrodynamic and sediment data in Lake Okeechobee with analyses examining mechanisms affecting sediment resuspension in the lake. Lake Okeechobee is a large subtropical lake located in south central Florida. Three‐dimensional flow velocities, suspended solids concentrations (SSC), and temperatures at four locations were measured from January 18 to March 5, 2000. Analyses of these data indicate that wind is the dominant factor in driving flow velocities and therefore transporting suspended solids. Wind direction also affects the SSC, especially in the north central and west littoral areas of the lake. The surface and bottom velocity components frequently flow in opposite directions, forming a stratification of the water column and preventing suspended solids from settling out. This retention of SSC in the water column may have a strong impact on the water quality of Lake Okeechobee. This study provides valuable storm event data and mechanism analyses, which will improve our understanding of the transport of suspended solids, thermal exchanges, and flow patterns within Lake Okeechobee.     

我国企业职业安全健康管理体系的建立与发展

随着全球经济一体化的发展,职业安全健康管理体系(OSHMS)成为继ISO9000和ISO14000后,企业持续发展中关注的又一个重要的标准化体系,职业安全健康已经成为当今世界各国日益关注的热点和焦点,我国于1999年10月颁布了《职业安全卫生管理体系试行标准》,通过两年多的实践,职业安全健康管理体系在我国得到了迅速的发展,在促进安全生产,保证本质安全方面起到了积极的作用。     

氧化铝皮带廊粉尘浓度超标原因及对策

分析了山西铝厂氧化铝皮带廓技术改造以后粉尘浓度超标的原因，提出了降低粉尘浓度的对策。