Spatiotemporal optical properties of dissolved organic matter in a sluice-controlled coastal plain river with both salinity and trophic gradients

Due to the combined effect of sluices and sea tide, the sluice-controlled coastal plain river would be characterized by both trophic state and salinity gradients, affecting the spatiotemporal optical properties of dissolved organic matter (DOM). In this study, we investigated the spatiotemporal variation of water quality parameters and optical properties of DOM in the Haihe River, a representative sluice-controlled coastal plain river in Tianjin, China. A significant salinity gradient and four trophic states were observed in the water body of the Haihe River. Two humic- and one protein-like substances were identified from the DOM by the three-dimensional fluorescence spectra combined with the parallel factor (PARAFAC) analysis. Pearson's correlation analysis and redundancy analysis (RDA) showed that the salinity significantly affected the abundance of chromophoric DOM (CDOM) but did not cause significant changes in the fluorescence optical characteristics. In addition, the effect of Trophic state index (TSI) on the CDOM abundance was greater than that on the fluorescence intensity of fluorescent dissolved organic matter (FDOM). In the water body with both salinity and trophic state gradients, TSI posed a greater influence than salinity on the CDOM abundance. Our results fill the research gap in spatiotemporal DOM characteristics and water quality variation in water bodies with both salinity and trophic state gradients. These results are beneficial for clarifying the joint influence of saline intrusion and sluices on the DOM characteristics and water quality in sluice-controlled coastal plain rivers.     

VOCs源强不确定性对臭氧生成及污染防治影响的模拟分析

本文基于三维区域空气质量模式WRF-Chem,通过修改模式化学模块,量化输出过程量和诊断量,提供了一种定量分析挥发性有机化合物(VOCs)源强不确定性对O3生成影响的方法.为无法定量计算VOCs源强导致的臭氧生成率[P(O3)]偏差,以及由此对O3体积分数分布和污染控制相关联的VOCs敏感区和NOx 敏感区分布的误判提供了方法参考.采用标准统计参数对WRF-Chem模式的气象场与污染场模拟性能进行了评估,相关指标均优于前人结果.以INTEX-B(intercontinental chemical transport experiment-phase B)人为源、FINNv1(fire inventory from NCAR version 1)生物质燃烧源和 MEGAN(model of emissions of gases and aerosols from nature)生物源作为基准源,并以卫星观测数据作为约束,对排放源进行改进,评估了源改进前后臭氧生成率[P(O3)]、O3体积分数和O3控制敏感区指标(Ln/Q)的变化情况.仅人为VOCs(AVOCs)源增加68％后,P(O3)模拟峰值增升比例达13％～82％,以北京观测站点为例,P(O3)模拟月均峰值增加42％(22.5×10-9 h-1).对P(03)形成贡献比例最大的主要化学反应是HO2+NO(占比约68％),AVOCs源增加68％后,该反应贡献比例下降至65％.在改进源下,P(O3)普遍增加达到2×10-9～4×10-9h-O3各季节增幅较大的区域均主要集中在京津冀、长三角和珠三角中心城市及周边区域,与我国大型城市区基本都是VOCs敏感区的结论一致.整体而言,VOCs源强改进后,Nox敏感区O3体积分数增加幅度不大,不超过4×10-9,而部分VOCs敏感区增幅超过20 x10-9.VOCs源强的不确定性会影响O3形成过程中Nox和VOCs敏感区的判断,特别是VOCs源强明显低估会夸大VOCs敏感区的范围,从而降低O3调控对策的有效性.     

珠三角某石化园区VOCs排放特征及影响评价

石化行业是挥发性有机物(VOCs)的重要来源之一,然而,当前石化行业VOCs研究多集中于炼油厂VOCs排放特征分析,针对有机化工和合成材料等子行业的研究较为缺乏.选取珠三角地区某石化园区中石油炼制、合成材料和有机化工3个主要行业的8家代表性企业和园区周围敏感点为研究对象,采集分析了包含22种含氧VOCs(OVOCs)在...     

Ni-W合金电镀有机废水处理新方法

利用自行研制的氧化絮凝复合床新方法处理了Ni W合金电镀有机废水,并对原有电镀废水处理工艺进行了分流处理改造。水处理工程运行结果表明 :该工艺技术经济实用、处理效果好、稳定性高,处理后的水质完全符合排放标准     

饮用水中有机污染物分子的VRML模型

用半经验量子化学计算MNDO-PM3方法,计算了腐殖酸(HA)和3-氯-4-(二氯甲基)-5一羟基-2(5H)-呋喃酮(MX)的几何构型、电子结构等．用MolSurf软件建立了HA和MX的VRML(虚拟现实造型语言)模型．     

活性炭吸附室内空气中挥发性有机化合物

活性炭吸附室内空气中挥发性有机化合物的１０％穿透时间与气相浓度及挥发性有机化合物的种类有关,通过对苯、甲苯和丙酮的实验研究,得出了由高浓度估算室内低浓度时炭床１０％穿透时间的经验公式ｔｂ,１＝ｔｂ,ｈ（Ｃ０,１／Ｃ０,ｈ）＾ａ,其中ａ值是与炭床性能及挥发性有机化合物种类有关的参数,可通过实验确定。     

EVALUATION OF RUNOFF,EROSION, AND PHOSPHORUS MODELING SYSTEM—SIMPLE1

ABSTRACT: The purpose of this study was to evaluate the performance of Spatially Integrated Models for Phosphorus Loading and Erosion (SIMPLE) in predicting runoff volume, sediment loss, and phosphorus loading from two watersheds. The modeling system was applied to the 334 ha QOD subwatershed, part of the Owl Run watershed, located in Fauquier County, Virginia, and to the 2240 ha watershed, Battle Branch, located in Delaware County, Oklahoma. Simulation runs were conducted at cell and field scales, and simulation results were compared with observed data. Runoff volume and dissolved phosphorus loading were measured at the Battle Branch watershed. Runoff volume, sediment yield, and total phosphorus loading were measured at the QOD site. SIMPLE tended to underestimate runoff volumes during the dormant period, from November to March. The comparison between observed and predicted dissolved phosphorus showed better correlation than for observed and predicted total phosphorus loading. Cell level simulations provided similar estimates of runoff volume and phosphorus loading when compared to field level simulations for both watersheds. However, observed sediment yields better compared with the values predicted from the cell level simulation when compared to field level simulation. Finally, results of model evaluation indicated that SIMPLE's predictive ability is acceptable for screening applications but not for site-specific quantitative predictions.     

反硝化条件下微生物降解地下水中的苯和甲苯

利用实验室含水层物质微环境实验,对地下水中常见有机污染物苯和甲苯在厌氧反硝化条件下的微生物降解进行了研究．通过10种方案实验结果的分析对比表明,在强化反硝化条件下,微生物利用NO₃^-作为电子受体降解苯和甲苯;降解苯和甲苯的反硝化细菌来自于含水层物质;微生物所需要的宏量营养由苯、甲苯和硝酸盐提供,而微生物所需要的其他痕量元素来自于含水层物质;环境的酸碱条件对微生物降解具有重要影响pH值过高（pH＞10）或过低（pH＜4）均抑制微生物降解过程的进行这些结论对研究地下水有机污染及其生物治理具有一定的理论和实际指导意义     

红壤区耕地有机物质的利用现状与开发策略

应用大量的调查和试验数据,论述了红壤区耕地有机物质资源的种类、数量及分布状况;分析了目前有机物质利用的现状及存在问题;探讨了开发有机肥料资源的对策。     

热带胶园土壤磷素形态和生物有效性

采用Hedley的磷素分级方法研究热带胶园土壤磷的形态,结果表明、热带胶园土壤磷主要以ResidualP、NaOH－Po和NaOH－Pi形态存在;各种形态磷的损失质量分数均高于38％;其中ResidualP和NaOH－Po的损失量最高,分别占全磷损失量的52％和16％,它们是长期耕作条件下热带胶园土壤磷两种最重要的有效磷源。