江汉平原县域尺度土壤有机质空间变异特征与合理采样数研究

土壤有机质含量是衡量土壤肥力和评价耕地质量的重要指标。在县域尺度下,利用合理数量的样点反映其空间分异特征具有重要意义。论文选取位于江汉平原腹地的湖北省公安县为研究区,布设了4 045个样点并测定其有机质含量,采用半方差分析得到土壤有机质空间变异特征,基于Moran’s I揭示空间变异较大地区,并通过二分法的思想逼近最佳合理采样数值。结果表明：研究区土壤有机质分布呈中等空间相关性,有6个局部区域的空间变异明显高于邻近地区,采样点数量与插值精度呈正相关,合理采样数为598个。研究结果可以为江汉平原县域耕地质量监测和管控提供指导。     

Comparison of extraction methods for polycyclic aromatic hydrocarbon determination in sediments

Different sample preparation methods for the determination of polycyclic aromatic hydrocarbons (PAHs) in lake and river sediments were compared and evaluated. Freeze‐dried sediment materials were extracted using Soxhlet extraction, ultrasonic agitation and digestion with various solvents and solvent mixtures. Similarly, clean‐up methods using various types of sorbents for separation of PAHs tested.

The following method gives the best results for the determination of PAHs: freeze‐dried sediment samples were extracted using Soxhlet extractor with dichloromethane (6 hr, dark), extracts were cleanup using Silica gel and a mixture of n‐hexa‐ne‐dichloromethane was used for the elution of PAHs.

This method was used for the determination of 7 selected PAHs in sediment samples from Finnish lakes and Czech streams.     

Assessment of heavy metal contamination of Great Kwa River estuary,southeastern coast of Nigeria by index of geochemical accumulation

Heavy metal concentration of the Great Kwa River estuary at the southeastern coast of Nigeria was assessed using an index of geochemical analysis (Igeo). Sampling from surface sediment was conducted quarterly for a period of one year, reflecting seasoning changes in the area. Igeo was calculated from the differences between actual current measurements and subtracted from background levels of “average shale” measurement. Based upon metals analyzed (Fe, Mn, Zn, Ni, Cu, Pb, Hg, and Cd), it was observed that there was a strong indication of potential ecological risk attributed to Cd, Zn, and Ni in the surface sediment. For effective control of pollution by metals in this fragile ecosystem, several recommendations were made including control of anthropogenic activities especially those of petroleum industry from offshore oil wells located in the area.     

土壤样品中四溴双酚A和六溴环十二烷的测定

建立了LC-MS/MS法同时测定土壤样品中四溴双酚A(Tetrabromobisphenol A,TBBPA)和六溴环十二烷(Hexabromocyclododecanes,HBCDs)的分析方法.样品经索氏抽提后,采用去活化硅胶柱进行净化.TBBPA、α-HBCD、β-HBCD和γ-HBCD的方法检出限分别为0.0315 ng.g-1、0.767 ng.g-1、0.197 ng.g-1和0.163 ng.g-1,方法加标回收率为59.0%—69.4%,可用于土壤样品中痕量TBBPA和HBCDs的测定.经过严格的质量控制,采用本方法对某郊区土壤样品进行了测定,其TBBPA和HBCDs的含量均在pg.g-1量级.     

固相萃取填料对水中脂肪族二元酸酯类增塑剂萃取效率的影响

以水中11种脂肪族二元酸酯类(ADEs)增塑剂的固相萃取-气相色谱-质谱法(SPE-GC-MS)为例,探讨了用C₁₈柱和HLB柱萃取水样时不同品牌、不同批号的SPE填料和C₁₈柱封端与否及相对应的洗脱溶剂不同配比对萃取效率的影响。实验结果表明:正己烷不可作为C₁₈柱和HLB柱的淋洗溶剂;11种ADEs用不同配比的二氯甲烷/正己烷溶剂体系洗脱,对C₁₈柱和HLB柱,不同SPE填料最佳二氯甲烷体积分数分别为0~60%和15%~20%;未经封端处理的C₁₈柱不适合作为ADEs的SPE柱;最佳溶剂洗脱体积为5 mL,样品穿透体积至少为200 mL;在优化条件下,11种ADEs方法检出限为0.2~0.5 μg/L,实际样品加标回收率为85.2%~113%,平行样相对标准偏差为5.5%~18%,各特性指标显示该方法正确度、精密度和灵敏度良好。     

免疫磁珠分离与实时定量PCR技术联合检测水中轮状病毒的研究

建立了一种免疫磁珠分离技术联合实时定量PCR快速定量检测水中轮状病毒的方法.通过制备能够分离水中轮状病毒的特异免疫磁珠,优化分离条件,建立了免疫磁珠分离前处理方法,并与逆转录、实时定量PCR结合,成功用于水中轮状病毒的检测.研究发现,在1 mL水样中加入10 μL轮状病毒免疫磁珠、0.25 μL Tween 20、孵育2 h可达到较好的分离效果;免疫磁珠可用于3%牛肉浸膏等常用病毒洗脱液中的轮状病毒的分离,表明该分离技术能与已有的病毒浓集方法良好地整合.免疫磁珠分离技术与实时定量PCR联合用于检测水中轮状病毒,全过程需时约5 h,检测限为1×10⁴　copies/mL(相当于3～4　PFU/mＬ),检测结果与细胞病变试验检测结果有良好的线性相关关系（R²=0.981 6）,表明其能较好地表征水样的病毒感染风险.对接种已知量的轮状病毒的污水处理厂二级出水、再生水、地表水、自来水等水样的实验表明,该法可用于各种水样中轮状病毒的检测.     

运用Excel函数汇总环境臭气样品嗅辨数据

本文以环境臭气样品的嗅辨分析数据为例。通过办公软件Excel中的If．Countif,And、Max等函数的嵌套应用,实现环境臭气样品嗅辨数据的自动统计并得出分析结果。     

地面水中石油类样品所用油标的选择

本文将气相色谱法与紫外分光光度法相结合,提出地面水中石油类项目测定所用油标的选择方法,并用０＃柴油代替大港原油作油标,进行水样测定,结果与实际状况较为相符。     

双程序双样品污染源监测采样方法探讨

本文针对当前环境监测四级站的污染源监测特点,提出了双程序双样品的监测采样方法．可避免排污企业受自身利益的驱使而对污染物排放采取弄虚作假的行为,使污染源监测更为客观公正,有利于污染源的监督管理。