挥发酚测定中三氯甲烷萃取废液的回收和显著性实验

1回收 :将三氯甲烷废液静置 ,分层 ,弃去水层 ,将三氯甲烷层放入蒸馏烧瓶 ,在通风橱内 ,放于电炉加热。保持电炉微热 ,加热蒸馏 ,弃去最初的几毫升馏出液 ,收集 61～ 63℃的馏分 ,待烧瓶内剩下 2 0～ 30毫升残液时 ,停止蒸馏。回收过程结束 ,得到经回收的三氯甲烷。2采用回收的和分析纯的两种三氯甲烷分别测定酚时 ,在酚的空白试验值和萃取吸光值上存在着显著性差异 ,故两种三氯甲烷不能混用 ;而校正吸光度之间不存在显著性差异 ,故当采用两种三氯甲烷分别测定时 ,对酚的校准曲线和酚的测定结果没有影响挥发酚测定中三氯甲烷萃取废液的回收…     

用蒸馏法回收实验废水中三氯甲烷

1方法 :将蒸馏瓶置于事先预热至 75± 1℃的恒温水浴锅中 ,连接好冷凝管及弯接管。将50 0 ml三氯甲烷废液经长颈漏斗倒入蒸馏瓶中 ,安装好温度计 (由瓶塞处插入 )。开启冷凝水 ,收集61～ 62℃沸点的蒸馏液。 2效果 :回收 50 0 ml废液约需 1 .5小时 ,三氯甲烷回收率在 70 %以上 ;三氯甲烷馏出液在 652 nm处的吸光度不随时间而改变且皆为零 ,其透光率与分析纯三氯甲烷一致。回收后的三氯甲烷作为水中阴离子洗涤剂的萃取剂其萃取效率与分析纯三氯甲烷一致用蒸馏法回收实验废水中三氯甲烷@张爱东$上海市闸北区环境监测站!上海200072 @李可群$…     

氯仿的回收

三氯甲烷是化验室的常用有机溶剂,用量大且试剂也很贵。我们从建站后就对使用的废试剂进行了收集,现在废液已堆积了很多,如若倒掉将造成污染,作者参考有关资料,并在实践中做些改进,提出简单易行的回收利用方法。其纯度经实验,表明完全可以回用于监测分析。     

亚甲蓝分光光度法测定阴离子表面活性剂的改进

在用亚甲蓝分光光度法测定水中阴离子表面活性剂中,积累点滴经验,供参考. 1 萃取方法 《水和废水监测分析方法(第3版)》[1]中,采用三氯甲烷多次重复萃取后定容50 mL,萃取工作量和三氯甲烷用量都较大(方法1).现改为在水样中加入三氯甲烷10 mL萃取,激烈振摇30 s,定容25 mL,静置分层.将三氯甲烷层放入预先盛有50 mL洗涤液的第2个分液漏斗内,重复上述操作1次.合并所有三氯甲烷萃取液至第2个分液漏斗中,激烈振摇30 s,静置分层,将三氯甲烷层通过装有脱脂棉的漏斗,放入25 mL具塞比色管中,再用三氯甲烷5 mL萃取洗涤液1次,三氯甲烷层并入比色管,加三氯甲烷至标线,摇匀.在652 nm处,以三氯甲烷为空白,测定三氯甲烷萃取液吸光值(方法2).     

顶空气相色谱法测定水中三氯乙醛的条件控制

探讨了顶空气相色谱法测定水中三氯乙醛的条件控制，阐述了加碱量对测定结果的影响，以及加热温度过高或加热时间过长导致三氯甲烷响应值变低的原因。结果表明，在5.0 mL水样中加入0.4 mL 5 mol/L NaOH水溶液，于45 ℃条件下加热30 min，可使目标产物三氯甲烷的响应值及稳定状态达到最佳。方法在2.00 μg/L～30.0 μg/L范围内线性良好，检出限为0.5 μg/L。对三氯甲烷背景浓度较高的自来水样品的加标回收率为88.3%～105%，RSD为6.3%。     

简化亚甲蓝分光光度法测定水中阴离子洗涤剂

亚甲蓝分光光度法测定水中阴离子洗涤剂,在加入亚甲蓝溶液后,需用三氯甲烷多次萃取洗涤,操作繁琐,不适合大批量样品测定。今简化成用三氯甲烷重复萃取两次(每次15mL)。将此萃取液通过洗涤液反洗一遍,再用三氯甲烷10mL萃取洗涤液1次,作吸光值测定。     

低浓度阴离子洗涤剂亚甲兰分光光度法测定的方法改进

1主要测定步骤 :取 1 0 .0 0 ml十二烷基苯磺酸钠使用液 ,加 2 5 ml亚甲兰溶液、1 5 ml三氯甲烷 ,激烈振荡 30秒。静置分层 ,轻轻拍打分液漏斗使附着在内壁上的三氯甲烷液珠降落。将三氯甲烷层放入预先盛有 30 ml洗涤液的第二个分液漏斗内。激烈振荡 30秒静置分层。轻拍分液漏斗壁使附着在壁上的三氯甲烷液珠降落。在 65 2 nm处以三氯甲烷为参比 ,采用直接流入 3厘米比色皿进行测定。 2与标准方法相比 ,绝对吸光值提高1 0倍 ,灵敏度提高 2 .5倍。 n=5时变异系数为5 .8%。低浓度阴离子洗涤剂亚甲兰分光光度法测定的方法改进@郝永红$邯郸市环…     

几种降尘捕集方法的对比实验：乙二醇作为降尘捕集剂的应用

本文提出了用乙二醇水溶液作降尘捕集剂,以解决原降尘采样方法中捕集剂蒸发与冰冻的问题,并报告了乙二醇空白实验、尘样回收实验的结果与五种圆形降尘缸集尘方法的对比实验结果.     

利用top-down线性拟合评定顶空气相色谱法测定水中卤代烃的不确定度

根据top-down技术中的线性拟合法,在不同时间里运用顶空气相色谱对水中卤代烃标准溶液的5个浓度进行多次测定。以三氯甲烷为例,通过计算和评定,得出当三氯甲烷的测定浓度在1.50~24.00 mg/L时的不确定测量公式。     

克拉玛依市自来水中三卤甲烷的测定与评价

源水氯化消毒目前仍是广泛而经济的消毒方法。消毒过程可产生三氯甲烷、一溴二氯甲烷和二溴一氯甲烷等挥发性卤代烃类污染物，这些物质对人体具有潜在危害。对此，本文采用静态顶空气相色谱法对克拉玛依市居民自来水中的三卤甲烷进行了定性定量检测和评价，经质谱定性自来水中存在三氯甲烷、一溴二氯甲烷和二溴一氯甲烷。对28个水样的检测结果表明，克拉玛依市自来水中的三氯甲烷、一溴二氯甲烷和二溴一氯甲烷均符合国家生活饮用水标准。     

土层中石油烃类污染物索氏抽提流程改进及回收氯仿资源化研究

通过对土层中石油烃类污染物索氏抽提流程的改进 ,实现蒸馏氯仿的回收与再利用。实验结果表明 ,用改进索氏抽提流程测的有机物含量与传统的流程相比 ,所减少的石油烃类物质损耗占总石油物质含量的 1 0 % ;同时 ,蒸馏回收的氯仿的 70 %可以重新用于索氏抽提 ,由此产生的误差小于 1 % ,不会影响残油微生物降解试验的分析精度 ,具有资源回收与保护环境的双重效应     

Effects of middle-term land reclamation on nickel soil-water interaction: a case study from reclaimed salt marshes of Po River Delta,Italy

Reclaimed salt marshes are fragile environments where water salinization and accumulation of heavy metals can easily occur. This type of environment constitutes a large part of the Po River Delta (Italy), where intensive agricultural activities take place. Given the higher Ni background of Po River Delta soils and its water-soluble nature, the main aim of this contribution is to understand if reclamation can influence the Ni behavior over time. In this study, we investigated the geochemical features of 40 soils sampled in two different localities from the Po River Delta with different reclamation ages. Samples of salt marsh soils reclaimed in 1964 were taken from Valle del Mezzano while soils reclaimed in 1872 were taken nearby Codigoro town. Batch solubility tests and consecutive determination of Ni in pore-water were compared to bulk physicochemical compositions of soils. Bulk Ni content of the studied soils is naturally high, since these soils originated from Po River sediments derived from the erosion of ultramafic rocks. Moreover, it seems that Ni concentration increases during soil evolution, being probably related to the degradation of serpentine. Instead, the water-soluble Ni measured in the leaching tests is greater in soils recently reclaimed compared to the oldest soils. Soil properties of two soil profiles from a reclaimed wetland area were examined to determine soil evolution over one century. Following reclamation, pedogenic processes of the superficial horizons resulted in organic matter mineralization, pH buffer, and a decrease of Ni water solubility from recently to evolved reclaimed soil.     

Does irrigation with reclaimed water significantly pollute shallow aquifer with nitrate and salinity? An assay in a perurban area in North Tunisia

In Tunisia, reclaimed water is increasingly used for irrigation in order to mitigate water shortage. However, few studies have addressed the effect of such practice on the environment. Thus, we attempted in this paper to assess the impact of irrigation with reclaimed water on the nitrate content and salinity in the Nabeul shallow aquifer on the basis of satellite images and data from 53 sampled wells. Ordinary and indicator kriging were used to map the spatial variability of these groundwater chemical parameters and to locate the areas where water is suitable for drinking and irrigation. The results of this study have shown that reclaimed water is not an influential factor on groundwater contamination by nitrate and salinity. Cropping density is the main factor contributing to nitrate groundwater pollution, whereas salinity pollution is affected by a conjunction of factors such as seawater interaction and lithology. The predictive maps show that nitrate content in the groundwater ranges from 9.2 to 206 mg/L while the electric conductivity ranges from 2.2 to 8.5 dS/m. The high-nitrate concentration areas underlie sites with high annual crop density, whereas salinity decreases gradually moving away from the coastline. The probability maps reveal that almost the entire study area is unsuitable for drinking with regard to nitrate and salinity levels. Appropriate measures, such as the elaboration of codes of good agricultural practices and action programs, should be undertaken in order to prevent and/or remediate the contamination of the Nabeul shallow aquifer.     

基于数值模拟的河道再生水补充区地下水监测网构建

再生水作为改善城市景观用水纳入河道,可其对地下水具有潜在的污染风险。通过构建区域地下水数值模型,应用质点追踪技术,计算出永定河补水区在河湖受水后地下水5 a运移1.47 km、20 a运移6.32 km,年均运移0.32 km。在数值模拟的基础上,依据地下水运移轨迹,结合区域水文地质条件,将研究区划分为核心监控区、二级监控区和控制监控区3个地下水监测分区,并提出各分区地下水监测井的布设原则及布设方式,实现地下水环境监测网络的优化。     

Reliable test methods for the determination of a natural production of chloroform in soils

Chloroform is one of the most frequently found anthropogenic groundwater contaminants. Recent investigations, however, suggested that chloroform in groundwater may also originate from a natural production in soils. As societies response to the occurrence of chloroform in groundwater may depend upon its origin as anthropogenic or naturally produced, test methods are needed to measure the potential of natural soil chloroform production. Field measurements of ambient air and soil air, and field and laboratory incubation studies were evaluated for measurement of relative soil chloroform production at a site with four different vegetation types (spruce forest, beech forest, grassland, and grain field) on comparable geological soil. All test methods showed varying soil production of chloroform with spruce forest soil being most productive and grain field soil being least productive. Field measurements of the ratio of soil air to ambient air chloroform concentrations exhibited the smallest difference between high production and low production areas, whereas laboratory incubation studies showed the largest difference. Thus, laboratory incubation studies are suggested as most efficient for estimating relative chloroform production in soil. The study indicated that soil samples should be tested not more than 14 days after sampling. Furthermore, it was found that potentially limiting compounds, such as chloride or nitrate, are not needed to be added in spike experiments to obtain reliable production results. However, it should be recognized that the processes of soil chloroform production are not known yet in all details. Other factors than those studied here may affect the test methods for soil chloroform production too.     

Risk assessment and loading capacity of reclaimed wastewater to be reused for agricultural irrigation

The reuse of treated municipal wastewater should be one of the new water resource target areas. The suitability of the reuse of wastewater for agricultural irrigation has to consider health risk, soil contamination and the influence of the reclaimed water on crop growth. In this work the aim is to use quantitative risk analysis to assess the health effects related to reclaimed water quality and to calculate the loading capacity of reclaimed wastewater in terms of the heavy metal accumulation. The results of chemical risk assessment show there would be slightly significant health risk and what risk there is can be limited within an acceptable level. The following exposure pathway: reclaimed water-->surface water-->fish (shellfish)-->human, and arsenic risks are of more concern. In terms of reuse impact in soil contamination, the most possible heavy metal caused accumulation is arsenic. The irrigative quantity has to reach 13,300 m(3)/ha to cause arsenic accumulation. However, only 12,000 m(3)/ha is essential for rice paddy cropland. The high total nitrogen of reclaimed water from secondary treatment makes it unfavorable for crop growth. The recommended dilution ratio is 50% during the growth period and 25% during the maturity period.     

Estimating the Microbial Risk of E. coli in Reclaimed Wastewater Irrigation on Paddy Field

Microbial risk was quantified to assess human health risk as a result of exposure to E. coli in reclaimed wastewater irrigation. Monitoring data on E. coli were collected from pond water in paddy rice plots during the growing season. Five treatments were used and each was triplicated to evaluate the changes in E. coli concentrations in experiments performed in 2003 and 2004. The Beta-Poisson model was used to estimate the microbial risk of pathogen ingestion among farmers and neighboring children. A Monte Carlo simulation (10,000 trials) was conducted to estimate the risk associated with uncertainty. In this study, risk values ranged from 10⁻⁴ to 10⁻⁸. UV-disinfected irrigation water showed a lower risk value than others, and its level was within the range of the actual paddy rice field with surface water. Agricultural activity was thought to be safer after 1–2 days, when the paddy field was irrigated with reclaimed wastewater. Also, children were found to have a greater risk of infection with E. coli. This paper should be viewed as a first step in the application of quantitative microbial risk assessment of wastewater reuse in paddy rice culture.     

用鱼类急性毒性试验分析死鱼事故原因

采用鱼类急性毒性试验方法分析、判断死鱼事故原因,不仅快速、简单、灵敏、直观,社会效益好,而且解决了单用几个理化测试数据,难以分析说明死鱼事故直接原因的难题,适于推广使用。     

Scots pine needles macronutrient (N, P, K, CA, MG, and S) supply at different reclaimed mine soil substrates—as an indicator of the stability of developed forest ecosystems

A main objective of restoration and afforestation at post-mining sites is establishing a long-term sustainable ecosystem which depends on adaptations of tree species and which in turn depends on the soil nutrient flux. The nutrient concentration (nitrogen (N), P, K, Ca, Mg, and sulfur (S)) of Scots pine needles was investigated in reclaimed mine soils (RMS) located at the following post-mining sites: a sand mine pit, spoil heap from a lignite mine, spoil heap from a S mine, and a carbonaceous spoil heap from an underground coal mine. The control plots were arranged on natural forest sites adjacent to the post-mining sites. A higher level of foliar nutrients was noted in the carbonaceous RMS, while lower levels were found in RMS on the spoil heap following lignite mining. The characteristics of the substrate were found to exert greater effect than mineral fertilization (performed at the onset of reclamation) on the tree stand characteristics, needle length and foliar nutrient concentration. While the soils and trees were most deficient in N, negative symptoms have not been noted to this date in tree stands at reclaimed mine sites. Trophic ratings were recommended based on statistical correlations and groupings between N and P contents in needles and needles length (mean length of 300 needles) while nutrient ratings were recommended from statistical differences and groupings of the RMS substrates.     

Carbon sequestration in reclaimed manganese mine land at Gumgaon, India

Carbon emission is supposed to be the strongest factor for global warming. Removing atmospheric carbon and storing it in the terrestrial biosphere is one of the cost-effective options, to compensate greenhouse gas emission. Millions of acres of abandoned mine land throughout the world, if restored and converted into vegetative land, would solve two major problems of global warming and generation of degraded wasteland. In this study, a manganese spoil dump at Gumgaon, Nagpur in India was reclaimed, using an integrated biotechnological approach (IBA). The physicochemical and microbiological status of the mine land improved after reclamation. Soil organic carbon (SOC) pool increased from 0.104% to 0.69% after 20 years of reclamation in 0–15 cm spoil depth. Soil organic carbon level of reclaimed site was also compared with a native forestland and agricultural land. Forest soil showed highest SOC level of 1.11% followed by reclaimed land and agriculture land of 0.70% and 0.40%, respectively. Soil profile studies of all three sites showed that SOC pool decreased from 0–15, 15–30, and 30–45 cm depths. Although reclaimed land showed less carbon than forestland, it showed better SOC accumulation rate. Reclamation of mine lands by using IBA is an effective method for mitigating CO₂ emissions.