土壤中氰化物的快速测定——以江苏镇江电镀园区土壤监测为例

以电镀园区为例,利用流动注射仪对园区土壤中的氰化物进行了快速测定,并与传统分光光度法进行了比对.结果表明：流动注射法中准确度和精密度均满足监测要求;pH为3.8、蒸馏温度为125℃是氰化物测定的最佳实验条件;流动注射法和传统方法测试的结果相对标准偏差（RSD）均小于8％.该法具有分析速度快、稳定性好等特点,适用于大批量土壤样品测定.     

近年来流动注射分析在环境监测分析中的应用概况

Ruzicka和Hansen对流动注射分析法(FIA)分析原理、实验设备与仪器、实验技术及1981年前的应用进行了阐述.近二十年来FIA在各个不同学科领域得到广泛应用.其仪器设备也不断改进,日臻完善.FIA在环境监测分析领域的应用也极其广泛.LuQue等对八十年代FIA在环境监测中的应     

流动注射—原子吸收光谱分析

本文研究流动注射在原子吸收光谱仪中应用.主要优点是,省去了以往常规分析方法的标准系列配制工作,提高了分析速度.一、实验原理 实验装置如图1所示.贮液瓶A浓度为C_0的溶液以速率u_0流入样品池B,被搅拌均匀后以速率U流出吸入原子吸收雾化器.在t时刻,样品池溶液浓度C的变化率:     

水环境中Fe3+流动注射分析方法的研究

采用ZJ-1a金属元素自动分析仪的流动注射功能,首次以Fe3 与硫酸铵反应后,再与结晶紫显色溶液缔合生成稳定的络合物,从而对水体中痕量Fe3 进行了测定.考察了还原剂中硫酸浓度的影响、反应圈长度、流速等因素的影响,优化了实验条件.在优化实验条件下,测得Fe3 的检出限为4.6 μg/L,相对标准偏差为4.2%,对水体中的Fe3 进行样品分析,回收率为96.5%～103.0%,结果令人满意.     

断续流动法测定水中TN

在人工消解使水中N元素转化为NO3-N的基础上,利用Bran Luebbe AutoAnalyzer 3流动分析仪NO3-N NO2-N分析模块测定水中TN,这样,既充分利用了仪器资源,又实现了大批量样品分析.实验结果显示,相对标准偏差均＜2%,回收率在92.4%～106.8%之间,检出限较低,且系统运行稳定.     

CFA1100连续流动分析系统测定水中总磷

现有的流动分析仪器全部依赖进口,本文利用国产CFA1100连续流动分析系统,对水和废水中的总磷含量进行分析。实验结果表明,该流动分析系统测定总磷,曲线线性相关性好,准确度和精密度高。该连续流动分析系统与SKALAR SAN++流动分析仪测定结果相比无明显差异,且与钼酸铵分光光度法测定结果接近。利用该仪器测定总磷与传统方法相比,适用范围广,分析速度快,结果准确可靠。     

流动注射-亚甲基蓝分光光度法测定水中硫化物的验证实验

根据国家环境保护部发布的环境保护标准《水质硫化物的测定流动注射-亚甲基蓝分光光度法》(HJ824-2017),开展了该方法实验室内的验证实验,分别对校准曲线、全程序空白、检出限及测定下限、精密度、准确度这五个性能指标进行测试。实验结果表明:该五个性能指标验证结果均能满足方法要求,且实验室具备正确运用《水质硫化物的测定流动注射-亚甲基蓝分光光度法》该标准方法的能力。     

流动注射法测定水中总磷的研究

通过实验研究了流动注射法测定水中总磷的优越性，对方法的检出限、精密度和准确度进行了测定，并与钼酸铵分光光度法进行了比对，取得了满意的结果．     

支撑液膜在线萃取富集流动注射分光光度法测定水中痕量铬(Ⅵ)的研究

选用无毒性的磷酸三丁酯为流动载体,煤油为膜溶剂的支撑液膜萃取体系,建立了支撑液膜在线萃取富集流动注射分光光度法测定水中痕量铬( )的新方法。对实验条件进行了优化。在最优条件下,方法的检出限为0.5μg/L,线性范围为3.0～120μg/L。应用于地下水与工业废水中铬( )的检测,结果满意。     

在线液膜萃取富集流动注射分光光度法测定水中痕量对硝基苯酚

介绍了选用无毒性的磷酸三丁酯为流动载体,煤油为膜溶剂的支撑液膜萃取体系,建立了支撑液膜在线萃取富集流动注射分光光度法测定水中痕量对硝基苯酚的新方法。通过对实验条件的优化选择,得出该方法的检测限为0．002mg／L,线性范围为0．005mg／L～0．05mg／L。该方法应用于废水中对硝基苯酚的检测,结果满意。     

京杭运河常州段泥水界面无机氮交换过程模拟研究

分别在枯水期、平水期、丰水期利用原柱样静态释放实验对京杭运河常州段4个点位的无机氮界面交换过程进行模拟,并借助模拟结果对运河不同形态氮的界面循环过程进行了初步探讨。结果表明,全年NH+4N界面交换特征均表现为底泥向上覆水体释放,平均交换速率比较结果为平水期[182.3mg/(m2·d)]>丰水期[94.0mg/(m2·d)]>枯水期[29.5mg/(m2·d)],而底泥污染严重的下游点位释放通量高于其他断面;丰水期底泥为上覆水NO-3N的源,平水期和丰水期则成汇,且平水期底泥平均吸附速率若为枯水期的6倍;全年NO-2N交换过程表现底泥吸附的特征,枯水期交换速率极低,全年底泥DIN(总无机氮)输入量>输出量,底泥对高浓度上覆水NO-3N的吸附作用可能是底泥污染逐渐加重的原因。     

流溪河大型底栖动物群落结构及其影响因素

为了探究流溪河大型底栖动物的群落结构特征和关键影响因素,于2016年4月(平水期)、7月(丰水期)和11月(枯水期)对流溪河的14个采样断面进行了生态调查,共鉴定出133种大型底栖动物,隶属于55科127属。大型底栖动物平均密度和生物量分别为213 ind./m²和20.02 g/m²,寡毛类和水生昆虫的密度占优势,软体动物的生物量占优势。此外,结果表明流溪河大型底栖动物群落结构具有明显的时空变化。在空间方面,从上游至下游大型底栖动物种类数呈现逐渐减少的趋势,并且支流的大型底栖动物种类数高于干流；从上游至下游大型底栖动物密度和生物量变化无规律,支流大型底栖动物的密度明显高于干流,而生物量却明显低于干流；上游的大型底栖动物Shannon-Wiener多样性指数和Margalef丰富度指数均高于下游,支流的大型底栖动物Shannon-Wiener多样性指数和Margalef丰富度指数均高于干流,而Pielou均匀度指数是支流低于干流。在时间方面,平水期至枯水期大型底栖动物种类数呈现逐渐增加的趋势；密度分布为平水期＞枯水期＞丰水期,生物量分布规律与密度相似；Shannon-Wiener多样性指数和Margalef丰富度指数均为枯水期最高,平水期最低。流溪河大型底栖动物群落可划分为干流群落和支流群落,群落间物种组成存在显著性差异。综上结果表明:流溪河支流大型底栖动物群落结构较干游更加稳定,下游断面群落受到了较大程度的干扰,生态环境质量状况较差,影响大型底栖动物群落结构的主要因素为有机质、总磷和溶解氧。     

微波检测器在交通噪声车流量监测中的应用

阐述了微波车辆检测器的基本工作原理及主要特点,选取城市主干道和一级公路对交通噪声监测中所需要的车流量数据进行仪器与人工的比对监测,结果显示,昼夜总车流量误差率在5%左右,表明该仪器适用于道路交通的车流量连续监测。     

全流稀释风道机动车排放颗粒物采集系统的集成及其流量控制和调节

以机动车排放颗粒物采集和分析为主要目的,开发了全流稀释风道机动车排放颗粒物采集系统.文章阐述了全流稀释风道的系统集成以及流量控制系统的设计和调节,其中包括设计应用范围、主要技术参数、系统检定等.流量控制系统采用的关键技术,即文丘里管组合装配方式具有控制流量范围广、变更灵活的特点,可以适应小到摩托车,大到重型柴油车等不同类型车辆检测的需要.     

Terrain Discontinuity Effects in the Regional Flow of a Complex Karstified Aquifer

Karst aquifers are characterized by spatial heterogeneity due to the presence of highly permeable channels and conduits in low-permeable fractured rocks (matrix block). Recent studies have reported a close relationship between surface and subsurface water in karstic regions due to the water flow through a complicated network of paths formed by fracture intersections. Subsurface flow in karstified aquifers ranges between conduit flow, in large passages with relatively high flow velocities, and diffuse flow, in the matrix block where Darcy’s law is still valid. In this paper, we present the simulation of a complex karstified aquifer system in Crete, Greece, where the presence of main faults drastically affects the regional flow. A discrete fracture approach in conjunction with an equivalent porous medium approach was adopted to simulate the mixed flow in the area of interest. The simulation results have shown that the length and the orientation of the dominant faults, primarily during the rainy season, affect the flow field.     

Prediction of Pollen-Mediated Gene Flow Between Fields of Red Clover (<Emphasis Type="Italic">Trifolium pratense</Emphasis>)

Pollen-mediated gene flow between red clover fields by bumblebees is predicted by estimating or simulating the parameters in a gene flow model for insect-pollinated crops. Generally, the predicted level of gene flow was found to depend on the visiting bee species and the spatial arrangement of the red clover fields. When the fields are close to each other, the gene flow depends mainly on the typical foraging distance of the visiting bee species, but when the fields are far apart, the gene flow between red clover fields is more sensitive to the distances between red clover fields than to the actual bumblebee species that pollinates the fields. Using the suggested methodology, the gene flow may be predicted in different agricultural scenarios. For example, if the gene flow between red clover fields is mediated by Bombus terrestris and the red clover fields that were assumed to be quadrates with sides of 100 m are separated by 200 m, then the median gene flow is predicted to be 0.17%.     

Dynamic Hydrologic Simulation of the Bear Brook Watershed in Maine (BBWM)

Bear Brook Watershed in Maine (BBWM) consists of a pair of research watersheds, East Bear Brook (EBB) and West Bear Brook (WBB). Years of research and observations have shown both watersheds have high similarity in geographic and hydrologic characteristics; a simple comparison of hydrographs from these two watersheds further substantiates this similarity. The Object Watershed Link Simulation (OWLS) model was developed and used to simulate the hydrological processes within the BBWM. The OWLS model is a 3-dimensional, vector-based, visualized, physically-based, distributed watershed hydrologic model. Simulation results not only provide a close examination of hydrologic processes within a watershed, but also dynamically visualize the processes of flow separations and Variable Source Areas (VSA). Results from flow separations suggest that surface flow from riparian area is the predominate component for the flood rising limb and that macropore flow from riparian area dominates during the falling limb. Soil matrix flow has little effect flood period but is a persistent contributor to base flow. Results from VSA visualization demonstrate 3-D dynamic changes in surface flow distribution and suggest that downstream riparian areas are the major contributing area for peak flow. As water chemistry is highly relevant to the flow paths within a watershed, simulations have provided valuable information about source of stream flow and the water migration dynamics to support the study of watershed chemistry in the BBWM. More specific linkages between the chemistry behavior and the dynamic hydrologic processes should become the next simulation effort in the watershed study. There are many questions that are critical to watershed chemistry studies like: which flow component (surface flow, macropore flow, soil matrix flow) predominates during peak flows? How do the flow components distribute during a flood event? How do flow contributions differ between these two watersheds? Which portion of the watershed contributes the most to the peak flows? These questions remain unknown from previous observations and only can be addressed with a physically-based distributed model.     

Effect of sample flow rate and sampling duration on the absorption of NO2 in the sodium arsenite monitoring method

The effect of the two most critical parameters, the sample flow rate and sampling duration, on the absorption efficiency of NO2 in the sodium arsenite method of nitrogen dioxide determination in ambient air was studied. Laboratory experiments showed a high sensitivity to these parameters, which were subjected to variation during actual field monitoring. The reported NO2 absorption efficiency of the method of 82% at a flow rate of 0.2 l min-1 was found to be as low as 33% at a flow rate of 1.0 l min-1 for a sampling duration of 24 h. Similarly, a considerable decrease in absorption efficiency with increasing sampling duration from 2 to 24 h was observed at a particular flow rate. Correction factors for the absorption efficiency were evolved that can be used to update the existing database, as well as future NO2 data generated using this manual monitoring method.     

Small-scale temporal variation and the effect of urbanisation on extracellular enzyme activity in streams

The activity of six extracellular enzymes involved in the degradation of dissolved organic carbon compounds was measured in two highly urbanised and two minimally impacted streams east of Melbourne, Australia, using 4-methylumbelliferyl-substrates. Small-scale temporal variation in enzyme activity was determined by repeatedly sampling the same point in the water column, while the effect of flow was determined by sampling in regions of higher and lower flow in both stream types. Replicate samples showed that enzyme activity was not significantly different over small (minutes) time scales. On five of six sampling occasions the enzyme activity was unaffected by flow. On one sampling occasion in a minimally disturbed stream, the difference between the high- and low-flow regions was statistically significant (ANOSIM, Global R= 0.78, P= 0.03). Enzyme activity profiles (activities of the suite of enzymes) of the streams in urbanised catchments were different to those in minimally disturbed catchments. The measurements made in four different streams showed high reproducibility over short time periods (minutes) which lends greater credibility to analogous spatial studies. Although these results determined that small-scale temporal variability was not significant, and that the effects of flow were generally minimal, it is recommended that spatial and temporal variability in the stream be at least considered before any studies measuring extracellular enzyme activity in stream waters are carried out. Such an approach will lead to conclusions from measurements that are not likely to be confounded by variables such as flow rate or time.     

江苏某县地下水邻苯二甲酸酯类的检测与风险评价

在江苏某癌症高发区对地下水进行布点,采用固相萃取与气相色谱-质谱联用方法测定深层地下水和浅层地下水中邻苯二甲酸酯类(PAEs)的浓度。检测结果表明,地下水中PAEs污染程度较严重,邻苯二甲酸二丁酯(DBP)和邻苯二甲酸二(2-乙基己基)酯(DEHP)均有超标现象,其中,丰水期深层地下水和枯水期浅层地下水中DBP超标率达到100%,最大超标10.7倍。PAEs总质量浓度均值为10 034.56~14 872.91 ng/L,丰水期总浓度均值大于枯水期,浅层地下水的总浓度均值大于深层地下水。采用优化的USEPA风险评价模型,对PAEs进行人体健康风险评价,评价结果表明,该地区52.5% 地下水的PAEs总致癌风险超过10^-6的水质监控值,总非致癌风险在可接受范围内。