A land use regression model for predicting ambient volatile organic compound concentrations in Toronto,Canada

More than 25 studies have employed land use regression (LUR) models to estimate nitrogen oxides and to a lesser extent particulate matter indicators, but these methods have been less commonly applied to ambient concentrations of volatile organic compounds (VOCs). Some VOCs have high plausibility as sources of health effects and others are specific indicators of motor vehicle exhaust. We used LUR models to estimate spatial variability of VOCs in Toronto, Canada. Benzene, n-hexane and total hydrocarbons (THC) were measured from July 25 to August 9, 2006 at 50 locations using the TraceAir organic vapor monitors. Nitrogen dioxide (NO₂) was also sampled to assess its spatial pattern agreement with VOC exposures. Buffers for land use, population density, traffic density, physical geography, and remote sensing measures of greenness and surface brightness were also tested. The remote sensing measures have the highest correlations with VOCs and NO₂ levels (i.e., explains >36% of the variance). Our regression models explain 66–68% of the variance in the spatial distribution of VOCs, compared to 81% for the NO₂ model. The ranks of agreement between various VOCs range from 48 to 63% and increases substantially – up to 75% – for the top and bottom quartile groups. Agreements between NO₂ and VOCs are much smaller with an average rank of 36%. Future epidemiologic studies may therefore benefit from using VOCs as potential toxic agents for traffic-related pollutants.     

壳聚糖三元接枝共聚物的合成及其阻垢性能

以壳聚糖(CTS)、衣康酸(IA)和马来酸酐(MA)为原料,以醋酸为溶剂、(NH_4)_2S_2O_8为引发剂,合成了CTS-IA-MA三元接枝共聚物。聚合反应的最佳条件为:反应温度90℃,n(CTS):n(IA):n(MA)=1:1.5:1.0,引发剂质量分数0.35%,反应时间5 h。通过傅立叶变换红外光谱(FTIR)表征,所得产物为CTS-IA-MA接枝共聚物。三元接枝共聚物质量浓度为50 mg/L、水样pH为中性或弱酸性时三元接枝共聚物对CaCO_3的阻垢效果较好。     

用废变压器油吸收废气中的二甲苯

以废变压器油作为吸收剂对二甲苯废气进行吸收处理,考察了影响二甲苯气体去除率的因素。实验结果表明:二甲苯废气流量为350 L/h、废变压器油喷淋量为40 L/h、进口二甲苯废气平日质量浓度为935 mg/m~3、吸收温度为18℃、吸收时间为50 min时,出口二甲苯气体质量浓度为35 mg/m~3,二甲苯去除率高达96.3%,小于GB16297—1996《大气污染物综合排放标准》中二甲苯质量浓度90 mg/m~3的排放标准。     

Polybrominated diphenyl ethers and their methoxylated metabolites in anchovy (<Emphasis Type="Italic">Coilia</Emphasis> sp.) from the Yangtze River Delta,China

Background, aim, and scope  

Polybrominated diphenyl ethers (PBDEs) and their metabolites are toxic to animals, and concentrations of the PBDEs metabolites can exceed those of the parent materials. But no information was available on concentrations of PBDEs metabolites in the lower Yangtze River in the region around Jiangsu Province of China, which is heavily urbanized and industrialized area. The aims of this study were to determine whether PBDEs and their methoxylated PBDEs (MeO-PBDEs) were accumulated in Coilia sp. in this area and to investigate the potential sources for these two kinds of brominated organic pollutants.     

贫营养异养硝化细菌的分离鉴定及硝化性能研究

从水库底泥中分离出1株贫营养异养硝化细菌,命名为菌株Y11。经菌株生理特性研究和16SrDNA测序,鉴定出菌株Y11属于假单胞菌属细菌(Pseudomonas sp.)。考察了温度、pH及C/N对菌株Y11的硝化性能影响,结果表明,菌株Y11进行硝化作用的最适温度为30℃,最适pH为中性,最适C/N为6.0,在该条件下进行4d的硝化反应,菌株Y11对氨氮去除率可达91.42%。     

新型材料淀粉微球对Cu2＋、Cr3＋和Pb2＋的吸附机理研究

以可溶性淀粉为原料,在反相悬浮体系中合成N,N′-亚甲基双丙烯酰胺交联淀粉微球为载体,研究了新型吸附材料淀粉微球（cross-linked starch microsphere,CSMs）对Mn＋（Cu2＋、Cr3＋、Pb2＋）的静态吸附行为。利用扫描电镜、X射线衍射仪和红外光谱仪对微球及其吸附产物进行表征,分析讨论了3种金属原子结构,研究了吸附机理。结果表明：308K时,Cu2＋、Pb2＋和Cr3＋的饱和吸附量分别是2.43、0.30和0.27 mmol/g,CSMs对Cu2＋离子吸附能力最强,并且其通过物理吸附、配位吸附方式吸附Mn＋,并得出引起微球吸附能力大小可能与金属离子电荷、离子半径和外层电子排布的差异因素有关。     

小型燃油锅炉NOx的排放特征与管理控制

以68台燃油锅炉（≤10～MW）NOx排放实测数据为基础,通过统计分析方法,研究了NOx的排放特征;通过对比分析,探讨了我国燃油锅炉NOx排放控制与管理现状,讨论了进一步加强我国燃油锅炉NOx排放管理控制的可能性与可行性,并提出了相应的管理控制建议。结果表明,NOx平均排放浓度为318．2mg／m^3,基于燃料消耗量的平均排放因子为4．4kg／t,基于燃料发热量的平均排放因子为102．8ng／J,基于燃料氮含量的平均排放因子为2．1mg／mg;建议采取分阶段控制的方式,逐步提高NOx排放限制,从而实现控源减排目标。     

中小型工业窑炉NOx废气的净化技术与应用

介绍了中小型工业窑炉生产过程中排放NOx的现状,并针对NOx的治理问题,从工程应用角度,简述了湿法和干法净化NOx的原理和化学反应过程。讨论了NOx排放特性和NOx废气中NO2/NOx比例的问题。提出了影响NOx治理的主要因素,包括吸收剂、吸附剂、催化剂和设备的部分应用参数,并结合工程实例指出工程需要注意的问题。介绍了多项采用湿法和干法净化NOx的工程应用项目,丰富了中小工业窑炉NOx废气的治理的实践经验,为中小工业窑炉排放NOx治理奠定了基础。     

直播稻田渗漏水磷素动态变化及渗漏流失潜力研究

通过田间实验,对太湖流域丹阳地区直播水稻田不同施磷水平下渗漏水磷素动态变化特征及流失潜力进行了研究。结果表明,施磷能明显提高地下60cm以上深度土层渗漏水磷的含量。各土层渗漏液总磷浓度随土层深度的增加呈下降趋势。随着施磷量的增加,稻田渗漏水磷素含量也会随之增加。土壤磷素发生渗漏流失的土壤表层Olsen-P含量的"突变点"change-Point为25.17 mg/kg。当土壤中的Olsen-P浓度小于25.17mg/kg时,20～40cm土层渗漏水中TP浓度基本上不随土壤Olsen-P浓度的变化而变化,但当土壤中Olsen-P大于25.17mg/kg时,20～40cm土层渗漏水中TP浓度会大量增加,且土壤中的Olsen-P每增加10 mg/kg,渗漏水TP将增加0.21 mg/L。稻田当季累计土壤磷素渗漏流失负荷为1.02 kg/ha,占当季施磷量的2.80%。     

饮用水消毒副产物控制工艺研究进展

通过对氯、二氧化氯、紫外线等常见消毒工艺以及去除已生成消毒副产物的深度处理工艺进行了分析,探讨了各种消毒工艺的消毒性能和对消毒副产物的控制效果以及各种深度处理工艺对消毒副产物的去除性能,为实际水处理中消毒以及深度处理工艺的选择提供了参考。