化探样品中银和硒的电感耦合等离子体质谱法测定

用电感耦合等离子体质谱法测定了化探样品中银和硒,对实验条件进行优化,用混合酸(硝酸+氢氟酸+高氯酸)分解处理样品,用1μg/L115In作内标校正基体干扰和仪器漂移。Ag的线性范围为0～1.0μg/L,Se的线性范围为0～1.0μg/L,线性相关系数均为0.999以上。Ag,Se元素的检出限分别为0.005μg/L,0.006μg/L,测定结果的相对标准偏差(n=10)在7.0%～13.0%之间。用该方法测定了岩石、水系沉积物和土壤三种国家标准物质,测定结果均在化探样品分析规范要求误差内。更多还原     

原子荧光光度法同时测定水中的汞和硒

应用AFS-9130双道原子荧光光度计,用5%的盐酸做介质,1%的硼氢化钠做还原剂,同时测定水中的汞和硒,检出限分别为汞0.004 5μg/L,硒0.063μg/L;汞的回归方程I汞=750.506 4C-4.2 84 9,相关系数1.000 0;硒的回归方程I硒=43.318 9C-6.138 7,相关系数0.999 9;汞和硒的相对标准偏差分别为1.36%和1.19%.     

吹扫捕集-气相色谱质谱联用测定水中挥发性有机物的研究

建立了吹扫捕集(Purge-and-Trap)与气相色谱-质谱(GC/MS)联用测定水样中挥发性有机物(VOC)的方法,探讨了该方法可能出现的问题,提出了一些简单的解决方案,并对GC/MS条件进行了优化。结果表明,用这项技术可以得到可靠的校正曲线,各挥发性有机物在0.4μg/L～60μg/L范围内有良好的线性关系,检出限分别在0.0021μg/L～0.20μg/L之间,回收率在95.6%～106.4%之间,相对标准偏差在2.2%～4.4%之间。     

高效液相色谱质谱法直接测定地下水中痕量克百威的研究

建立了利用液相色谱-质谱(LC-MS/MS)法直接进样快速测定水中克百威的分析方法。对质谱条件和液相色谱条件进行了优化。在多反应监测模式MRM下,以甲醇-水(0.1%甲酸)为流动相对克百威进行定性定量分析。结果显示:克百威在0.5~10.0μg/L的范围内线性关系良好,相关系数0.999,方法的检出限为0.05μg/L;在1.5、 5.0和10.0μg/L等3个添加水平下,方法的回收率为86.0%~94.7%,相对标准偏差RSD为1.4%~2.9%。该方法无需衍生化操作,无需样品前处理,灵敏度高,抗干扰能力强,分析成本低,可用于地下水中痕量克百威的测定。     

SAN++连续流动分析仪同时测定水体中挥发酚和总磷的方法探究

采用SAN++连续流动分析仪同时测定水体中的挥发酚和总磷,在最佳实验条件下,挥发酚和总磷的标准曲线相关系数在99.9%以上,检出限分别为0.0006 mg/L和0.006 mg/L,精密度和准确度较好,相对标准偏差RSD均小于1%,挥发酚和总磷样品加标回收率范围分别为91.4%～97.5%和92.4%～97.4%,与传统手工比色法进行比对实验,两种方法测定结果无显著性差异。采用连续流动分析法同时测定挥发酚和总磷,自动化程度高,周期短,适合大批量样品同时检测。     

地下水中21种半挥发性有机物测定方法的优化研究

为研究建立同时测定地下水中21种半挥发性有机物的固相萃取-气相色谱-串联质谱(SPE-GC/MS)法,采用C_(18)和HLB固相萃取柱对地下水样品进行富集萃取,DB-5MS毛细管柱(30 m×0.25 mm×0.25μm)进行气相分离,单离子监测(SIM)扫描模式进行分析,并对进样速率、洗脱剂和pH等样品前处理条件进行优化,建立了固相萃取-气相色谱-质谱测定地下水中21种半挥发性有机物的检测方法。研究结果显示:21种半挥发性有机物的标准曲线在0.1～1μg/mL范围内,线性关系良好。平均回收率基本在80%～120%之间,精密度在1.70%～8.79%之间,检出限在0.022～0.045μg/L之间,均低于《地下水质量标准》(GB/T 14848—2017)一类水限值。研究结果表明,本方法操作简便、有机试剂消耗量少、灵敏、准确,可用于地下水中多种半挥发性有机物的同时检测。     

氢化物发生原子荧光法测定漳泽水库中的铅含量

以过硫酸铵为氧化刺将Pb氧化成亚稳四价态,与KBH4作用生成PbH4,应用氢化物发生原子荧光法测定漳泽水库中痕量Pb.文中考察了溶液的酸度、氧化掩蔽剂用量、反应时间以及共存元素对测定铅的影响.在优化条件下,该方法的检出限为0.69μg/L,线性范围为0.80～200μg/L,相对标准偏差RSD为4.04%(浓度为10μg/L).该法具有灵敏度高、简便、快速、重现性好等优点.应用于漳泽水库中铅的测定,回收率为90.25%～110.14%.结果满意.     

流动注射比色分析法在线蒸馏并测定挥发酚

本文采用流动注射法在线蒸馏并测定水和废水中挥发酚,该方法在2．0μg～200μg／L phenol/L线性关系r=0．9998,精密度RSD=0．784％,回收率=101．4％,每小时能测定8个样品,试剂消耗量少,适用于饮用水、地表水、盐水、生活和工业排放废水中挥发酚的测定。     

黄河内蒙古段沉积物中汞含量及形态研究

为探明黄河内蒙古段水体沉积物中的汞含量及其形态分布特征,以黄河内蒙古段干流水体柱状沉积物为研究对象,采用改进的Tessier形态逐级提取法,分级提取水溶及可交换态、碳酸盐及铁锰氧化物结合态、腐殖质结合态、难溶有机质结合态及硫化物态和残渣态5种形态汞,用氢化物发生-原子荧光分光光度法测定汞含量,结果表明:黄河内蒙古段柱状沉积物中汞含量为12.1~47.1μg/kg,平均为21.4μg/kg;从整体上看,左岸沉积物中汞含量高于右岸,从上游至下游,汞含量呈先上升后下降趋势;沉积物中汞以腐殖质结合态为主,残渣态次之;腐殖质结合态汞含量随深度增加呈明显下降趋势,其他形态汞含量随深度增加呈上升趋势。     

吹扫捕集气相色谱法检测水中苯系物

用吹扫捕集气相色谱法检测苯系物,该技术前处理方式不使用有机溶剂,对环境不会造成二次污染,且具有取样量少、灵敏度高、检出限低、简便快速、结果准确等优点。方法检出限分别为:苯0.3μg/L,甲苯0.5μg/L,乙苯0.5μg/L,对间二甲苯0.7μng/L,邻二甲苯0.7μg/L,苯乙烯0.6μg/L;本法测定苯系物的RSD为0.94%～2.64%,加标回收率为95.7%～105.3%,适用于自来水中低浓度苯系物的分析。     

饮用水源水中痕量挥发性有机物分析方法研究

目前，种类繁多的挥发性有机化合物不仅广泛用于工业，也大量应用在日常生活中，导致饮用水源水受到一定程度污染，饮用水的质量直接影响着人类的健康，日本、美国等经济发达国家对各类挥发性有机污染物都制定了严格的控制标准，我国于2005年6月开始实施的新的《城市供水水质标准》新增加了25种VOC化合物作为严格控制的目标化合物，包括5种苯系物、6种氯苯类化合物和14种卤代烃类化合物，由于水源水中VOC含量低，对分析人员和仪器需求很高，本研究目的是建立饮用水源水中痕量挥发性有机物标准分析方法，研究采用吹扫捕集／气相色谱／质谱联用技术对饮用水源水中45种痕量挥发性有机物进行分析结果表明，本方法所分析45种目标化合物的回收率范围为74％～122％，精密度RSD％范围为4．2％～22．0％，检测限范围为0．04μg／L～0．15μg／L。均满足水源水痕量分析的要求，根据研究结果可得出本方法可作为水利水质监测部门饮用水源水中痕量挥发性有机物行业标准监测方法。     

Temporal trends in near-shore sediment contaminant concentrations in the St. Clair River and potential long-term implications for fish tissue concentrations

Near-shore surface sediment of the St. Clair River (Ontario) extending along 9 km of waterfront downstream of local industries were contaminated with mercury (Hg), hexachlorobenzene, hexachlorobutadiene and octachlorostyrene based on data collected in 2006 and 2008. However, unlike Hg, concentrations of organic compounds were low at most stations suggesting improvements in sediment quality since 2001 (post sediment remediation projects). Concentrations of Hg were greater than Provincial Sediment Quality Guidelines and ranged as high as 41 μg/g in the surficial 0–5 cm sediment. Measured (2001–2004 data) and estimated (2006 data) concentrations of methyl Hg in invertebrates were greater than concentrations in invertebrates collected from upstream reference stations. Predicted methyl Hg concentrations in walleye using food chain multipliers, benthic invertebrate Hg tissue concentrations and current sediment concentrations exceeded human health consumption guidelines and were consistent with measured sport fish data supporting assumptions about Hg biomagnification. Historical data showed that for fish collected from the lower St. Clair River and Lake St. Clair, Hg concentrations have declined since 1978, but have remained stable since the mid 1980s, consistent with the sediment Hg data. The consistency in the sediment and fish datasets and the absence of a known significant local point source of Hg suggests that the sediment may be an important source of Hg to the St. Clair River food-chain.     

Oligonucleotide-based fluorescence system for sensitive and selective detection of Ag(I) ions in aqueous solution

In this letter, a new homogeneous assay with high sensitivity and selectivity was developed for the detection of silver ions in aqueous media at room temperature by using EvaGreen (EG), polycytosine oligonucleotide C?? and single-walled carbon nanotubes (SWNTs). The fluorescence of EG is weak in the absence or presence of randomly coiled C?? After C?? interacted specifically with Ag(+) ions through C-Ag(+)-C bonding, C?? would form a folded structure that preferentially binds to EG. As a result, the fluorescence of the mixture of C?? and EG increased in the presence of Ag(+). As having a higher affinity with ssDNA and organic dye, SWNTs could easily form a complex with EG and C??, which led to fluorescence quenching of the dye. Additionally, they can also effectively reduce background-signal fluorescence of the dye and greatly improve its specificity. Under the optimum conditions, the EG/C?? probe exhibited a high selectivity towards Ag(+) over other metal ions. The detection limit was up to 7.4 nM (0.8 ppb). This method is low cost, label-free, and easy to use.     

Biogeochemical Investigation of Big Creek Marsh,Lake Erie,Ontario

Geochemical composition of sediment, uptake of nutrients and metals by macrophytes, and nutrient and metal concentration in the water was investigated at six selected stations in Big Creek Marsh, Ontario. The maximum concentrations of Pb, Ni, Cu, Cr, and Zn in marsh sediment (86, 48, 38,119, and 383 μg/g dry weight, respectively), were lower than the concentration of these metals found in fine-grained surficial sediments of Lake Erie, and maximum concentration of As and Hg in marsh sediment (112 and 0.930 μg/g dry weight, respectively) were higher than As and Hg concentration in most of Lake Erie surficial sediments. Occurrence of DDT metabolites in marsh sediment reflects extensive use of DDT in the Big Creek drainage basin prior to 1970. Increase of total Kjeldahl Nitrogen and NH₄-N in marshwater was observed at a few sampling stations in November. Submerged macrophytes Myriophyllum, Chara, and Elodea sps. accumulated larger quantities of Pb, Cu, Ni, Cd, and Cr than emergent macrophytes at the stage of maximum development. Correlation between Ca and Pb, Cu, Ni, and Cr concentration in sampled macrophytes was observed; however, there was no correlation between Ca and Zn in these plants.     

稻草强化生物膜浮床脱除工业尾水中氮素及COD的效果

工业污水处理厂排放的尾水中总氮含量偏高,容易引起地表水体的富营养化。为了提高尾水中总氮的去除效率,通过模拟稳定塘静态和动态试验,对比了不同稻草添加量(0,0.18,0.54 g/L)强化生物膜浮床脱除工业尾水中总氮(TN)的效果。静态试验结果表明:随着稻草量的增加,TN的去除率显著提高;10 d后,添加0(CK)、0.18 g/L(T1)和0.54 g/L(T2)稻草的尾水中,TN去除率分别为18%,40%,93%。动态试验结果显示,水力停留时间(HRT)为 4 d时,CK、T1和T2的平均TN去除率分别为10%,22%,49%,且3种情况下的进出水COD浓度无显著差异。这主要是由于稻草通过缓慢释放碳源为生物膜中异养反硝化细菌提供可利用的有机物。研究成果可为工业尾水深度处理脱氮技术提供参考。     

絮凝剂作用下黏性细沙絮凝沉降规律研究

细颗粒泥沙广泛分布于河流、水库、河口及海岸水体中,其絮凝沉降及输移规律是泥沙运动力学中一个重要课题。采用自制沉降实验装置,实验观测了不同絮凝剂浓度、不同浓度黏性细颗粒泥沙的絮凝沉降过程,分析研究了黏性细沙絮凝沉降规律。结果表明：聚合氯化铝(PAC)絮凝剂比较稳定,PAC溶液浓度对不同泥沙浓度絮团沉速的影响均较小,最佳投放浓度可统一采用0.08 g/L。阳离子型聚丙烯酰胺(CPAM)絮凝剂对泥沙浓度的反应最为敏感,絮凝剂最佳投放浓度随着泥沙浓度的变化分为3个稳定段和2个敏感段,稳定段CPAM最佳投放浓度分别为0.08、0.10和0.12 g/L,敏感段CPAM最佳投放浓度可采用区间插值方法选取。阴离子型聚丙烯酰胺(APAM)絮凝剂最佳投放浓度随着泥沙浓度的变化分为2个稳定段和1个敏感段,稳定段APAM最佳投放浓度不随泥沙浓度的变化而变化,分别为0.08和0.10 g/L,敏感段APAM最佳投放浓度可采用区间插值方法选取。絮凝剂APAM的絮凝效果最好,絮凝剂CPAM的絮凝效果次之,絮凝剂PAC的絮凝效果较差。     

Watershed influences on the transport, fate and bioavailability of mercury in Lake Superior: Field measurements and modelling approaches

The issuance of fish consumption advisories in US states bordering Lake Superior has heightened the need for understanding the biogeochemical cycling and transformations of mercury in this great lake. Major routes of mercury (Hg) transport to lakes include atmospheric deposition (wet and dry), direct discharges and riverine (watershed) inputs. The specific objectives of this ongoing study are to: (i) determine the speciation and bioavailability of Hg transported to Lake Superior (ii) determine the importance of watershed‐specific characteristics that control physical and chemical forms of Hg; (iii) identify key mechanisms controlling Hg bioavailability and speciation in near‐shore zones relative to open lake regions; and (iv) provide process‐level information to compliment concurrent development of Hg fate and transport models of the Lake Superior ecosystem. Three tributaries of Lake Superior were chosen for detailed field study based on previous results and particular watershed characteristics. Mixing zones represent a potentially important zone of Hg entry into the food chain, and were sampled for biota, water and sediment in transects between the tributary mouth and the lake end member. Sampling of open‐water sites was conducted during Environmental Protection Agency‐sponsored cruises on the research vessel Lake Guardian. Results from our work on Lake Superior tributaries demonstrate that dissolved organic carbon and methylmercury (MeHg) export was greatest from watersheds containing wetlands. In Lake Superior, concentrations of Hg species were small at pelagic stations (total mercury (HgT) averaged 0.49 ng/L, MeHg averaged 6.4 pg/L). In contrast, MeHg concentrations in tributaries ranged from 100 to 250 pg/L. Watershed sites dominated by wetlands exhibited the greatest MeHg concentrations, occasionally in excess of 12 ng/L. Samples of bulk zooplankton ranged from 20 to 130 ng/g dry weight HgT and from 15 to 45 ng/g dry weight MeHg, and demonstrated typical bioacculmulation of mercury as well as distinct seasonality in concentrations.     

电解Fenton法处理线路板生产废水中有机物质

研究了Fenton法对线路板生产废水中有机物质的处理效果,比较传统Fenton法和电解Fenton法处理效果。在同样反应时间里,电解Fenton法的COD平均去除率为55.7%,H2O2的最大投加量为3.75 g/L,而传统Fenton法的COD平均去除率为23.7%,H2O2的投加量为5.45 g/L。确定了电解Fenton法小试装置处理线路板废水的最佳处理条件。     

Does Manganese Influence Phosphorus Cycling under Suboxic Lake Water Conditions?

The comparative roles of iron and manganese in internal phosphorus loading were examined in a managed lake. Sediments and the water column of Irondequoit Bay, an embayment along Lake Ontario's southern shore, were sampled monthly during summer thermal stratification. Total phosphorus, total iron, and total manganese concentrations in the sediment averaged 1.389 ± 0.150 g/kg dry wt, 24.415 ± 0.760 g/kg dry wt, and 1.727 ± 0.053 g/kg dry wt, respectively. Elevated total phosphorus (maximum = 0.915 mg P/L) and soluble reactive phosphorus (maximum = 0.749 mg P/L) concentrations were observed in the hypolimnion. Sequential extraction of phosphorus fractions from the top 25 cm of deepwater sediment revealed that approximately 25% of phosphorus was stored in a redox-sensitive form, most likely associated with iron and manganese oxyhydroxides. Typically, phosphorus released from sediments is associated with iron, not manganese. However, iron and manganese profiles from the water column indicated that manganese from the sediment was cycling with phosphorus into the overlying waters, while iron did not demonstrate evidence of cycling. Although reductive dissolution of iron likely occurs in the sediment, iron was retained in the sediment and kept out of the water column by the maintenance of low concentrations of dissolved oxygen in the hypolimnion.     

臭氧-光降解-碳纤维处理石化RO浓水

针对石化行业的超滤/反渗透(reverse osmosis,RO)浓水处理问题,选取天津某港石化公司RO膜生产车间产生的RO浓水,采用臭氧-光降解-碳纤维处理技术,进行中试试验。结果表明:最佳pH值为8~9,臭氧最佳投加质量浓度为10.0~13.3 mg/L;系统最终出水COD的质量浓度小于40 mg/L,累计NH3-N去除率最高为44.6%,SS达到一级排放标准;处理RO浓水的成本为2.1元/t;增加内回流比,可以提高NH3-N去除率;碳纤维装置进水pH值为8时,吸附效率最高。