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1.
测定地表水中悬浮物的空白校正   总被引:1,自引:0,他引:1  
进行了测定地表水中悬浮物空白校正与不作空白校正的对比试验 ,得出不作空白校正存在较大误差 ,认为测定地表水中悬浮物时应作空白校正。同时用测定海水中悬浮物的方法作测定地表水中悬浮物的试验 ,试验效果较好 ,符合测定要求。建议可用测定海水中悬浮物的方法来测定地表水中悬浮物  相似文献   

2.
总磷是评价水质的一项重要指标,现对样品中悬浮物(泥沙)含量、加酸保存样品保存时间与调节pH值对总磷测定的影响进行研究。结果表明,随着沉降时间的延长总磷测定值逐渐降低,加酸保存的样品总磷测定值随保存时间的延长而增高,且测定时是否调回中性对测定结果基本无影响。故进行地表水中总磷的测定需严格按照标准规定的样品采样过程控制采样沉降时间,加酸保存,24 h以内进行测定,测定时无需调回中性。  相似文献   

3.
用离子色谱法测定环境空气中低浓度氯化氢,是通过测定氯离子质量浓度间接测定氯化氢的质量浓度,测定过程极易受外来氯离子的干扰,使空白值偏高。通过试验确定测定过程中可能存在氯离子干扰的环节,并采取一系列方法消除前期准备、采样和分析全过程中的干扰,以降低空白值。  相似文献   

4.
ICP-AES法和分光光度法测定工业废水中总磷的方法比较   总被引:1,自引:0,他引:1  
用ICP-AES法和分光光度法同时测定4种不同工业废水中的总磷含量,将2种方法的测定结果作比对。试验表明,ICP-AES法对国家标准样品的测定结果具有较高的准确度和精密度,4种废水样品测定结果的加标回收率为94.0%~110%,RSD在0.9%~3.2%之间。分光光度法适用于低浓度、低干扰样品的测定,对于高浓度含磷废水,取样体积和样品稀释倍数均会对其测定结果产生显著影响。消解样品经浊度-色度补偿后,分光光度法的测定结果精密度较低。  相似文献   

5.
建立了偏振能量色散X射线荧光光谱法测定土壤和沉积物中稀土元素的方法,该方法较传统的方法具有前处理简单、测量自动化程度高、灵敏度高和检出限低(检出限范围为0.05~2.80 mg/kg)等优点。对土壤和沉积物标准物质的测定结果表明:测定结果与认定值能较好吻合,相对标准偏差范围为0.2%~9.4%,能满足测试的需求。分别用该方法和电感耦合等离子体质谱法对实际样品进行测定,2种方法的测定结果有较好的一致性,表明该方法测定结果准确可靠,可用于实际样品的测定。  相似文献   

6.
为了比较差减法和直接法对水中总有机碳测定结果,分别配制差减法和直接法的工作曲线,并分别通过差减法和直接法对不同水体中的总有机碳含量进行测定。比较测定结果,发现差减法和直接法对较清洁水体样品的TOC测定结果误差不大,而对废水样品的TOC测定结果误差较大。  相似文献   

7.
在测定造纸废水悬浮物的过程中,采用絮凝沉淀法破坏废水中的胶体物质,从而提高抽滤速度,缩短测定时间。达到快速测定造纸废水中悬浮物的目的。  相似文献   

8.
通过应用FIA流动注射分析仪,成功进行水中挥发酚和氰化物的同时测定,测定数据准确、可靠、高效,大大缩短了测定时间,只需将两种标准配制成混合标样,一次取样完成两个项目的测定。回收率为93%~106%,相关系数达到0 9998以上。  相似文献   

9.
研究了水样静置30 min和全部混合立即测定2种前处理方法对江苏省环太湖15条主要出入湖河流总磷测定值的影响,结果表明,采样后静置30 min测定的总磷浓度较低,仅为全部混匀立即测定总磷浓度的46%~80%;水体中漂浮水华蓝藻数量是影响2种前处理方法总磷测定结果差异性的重要因素,去除漂浮水华蓝藻较多的7条入湖河流监测数据后,静置30 min测定的总磷浓度为全部混匀立即测定总磷浓度的71%~80%。提出,基于不同的测定目的,应有针对性地选择总磷前处理方法,在水环境质量状况评估时,可参照国家标准或最新技术规定的前处理方法执行,以保证总磷浓度的可比性;在进行总磷入湖通量研究时,建议采用全部混合立即测定的前处理方法,以反映水体中实际总磷浓度;在不同国家水体总磷浓度比较时,建议采用相同的前处理方法进行总磷浓度测定。  相似文献   

10.
系统研究了反应时间、水温、显色剂的用量及pH对游离性余氯测定的影响,优化选择最佳测定条件为控制水样pH<8,水温25℃,显色剂用量2.5 ml,加入显色剂后立即比色测定游离性余氯。在此条件下,测定3种生活饮用水游离性余氯,回收率为96.7%~99.8%,测定结果与《生活饮用水标准检验法》(GB 5750-85)中37.3滴定法颇为一致。  相似文献   

11.
An important research area in life sciences is devoted to modeling, prediction, and dynamics of gene-expression patterns. As clearly understood in these days, this enterprise cannot become satisfactory without acknowledging the role of the environment. To a representation of past, present, and most likely future states, we also encounter measurement errors and uncertainties. This paper surveys and improves recent advances in understanding the foundations and interdisciplinary implications of the newly introduced gene–environment networks, and it integrates the important theme of carbon dioxide emission reduction into the networks and dynamics. We also introduce some operational and managerial issues of practical working and decision making, expressed in terms of sliding windows, quadrants (modules) of parametric effects, and navigating (controlling) between such effects and directing them. Given data from DNA microarray experiments and environmental records, we extract nonlinear ordinary differential equations that contain parameters that have to be determined. For this, we employ modern (Chebychevian) approximation and (generalized semi-infinite) optimization. After this is provided, time- discretized dynamical systems are studied. A combinatorial algorithm with polyhedra sequences allows to detect the region of parametric stability. Finally, we analyze the topological landscape of gene–environment networks with its structural (in)stability. By embedding as a module and investigating CO2 emission control and figuring out game theoretical aspects, we conclude. This pioneering work is theoretically elaborated, practically devoted to health care, medicine, education, living conditions, and environmental protection, and it invites the readers to future research.   相似文献   

12.
In this article a comprehensive approach for the evaluation of possible health effects in an environmental impact assessment (EIA) is described, illustrated with the example of Amsterdam Airport Schiphol. Unlike many EIAs, we estimated quantitatively the impact of aircraft-related pollution in terms of the number of affected people for aircraft noise annoyance, odour annoyance and hypertension. In addition, an analysis of health registry data on cardiovascular and respiratory diseases and a short survey on annoyance and risk perception were carried out. The scope of a health impact assessment depends on the situation, available knowledge and data, concern in the population about the impact and the number of people concerned. It is important to pay attention to the perception of risks and concerns from all parties involved. Moreover, the results demonstrate that far more people outside the area for which standards apply were affected than inside.  相似文献   

13.
The San Francisco Bay estuary isused by over one million shorebirds during springmigration and is home to several hundred thousandduring the winter. Most shorebird use occurs in thesouthern reach of the estuary (South Bay). Thereduced water circulation and discharge fromindustrial sources in the South Bay are responsiblefor the highest levels of some trace elements in theestuary. Wintering shorebirds have been found to havestrong site fidelity to areas as small as a fewkilometers in the South Bay, which may increase theirexposure to contaminants near local point sources. Inaddition, different shorebird species foraging at thesame site have been shown to have differentcontaminant burdens. Thus, our objectives were totest whether contaminant burdens differed by species,or whether contaminant burdens differed in shorebirdscollected at adjacent sites. We examined thecontaminant profiles of two species of shorebirds,long-billed dowitchers (Limnodromus scolopaceus)and western sandpipers (Calidris mauri) thatforage together at two sites, Hayward and Newark,separated by 8 km in the South Bay. We usedmultivariate analysis of variance tests to compare thecomposition of 14 elemental analytes in their livertissues and estimated their molar ratios of Hg and Se. Composite samples were used for contaminant analysesbecause of the small body size of the shorebirds. Seven elemental analytes (Ag, Ba, Be, Cr, Ni, Pb, V)were below detection limits in a majority of thesamples so statistical analyses were precluded. Inthe measurable analytes (As, Cd, Cu, Hg, Mn, Se, Zn),we found no significant intra-site differences ofcontaminant profiles for the two species. We pooledthe samples to examine inter-site differences andfound significant differences in contaminant profilesbetween shorebirds at the neighboring sites (P = 0.03). Shorebirds at Newark had higher (P < 0.05) concentrations of As, Cd, and Se than those at Hayward. Dowitchers at Newark had concentrations of Hg and Se which were highly correlated (P < 0.003) in a mean molar ratio of 1:19, similar tothat reported in other birds. In the larger dowitcherspecies, we also examined exposure to 20organochlorine compounds. Organic analyses showedthat the dowitchers had been exposed to DDE, PCBs,dieldrin and trans-nonachlor, but with no significantdifferences in concentrations between Hayward andNewark (P > 0.05).  相似文献   

14.
土壤和底泥中砷、铬、锰测定的前处理技术   总被引:6,自引:0,他引:6  
试验了土壤和底泥中砷的前处理技术,其目的是能对土壤、底泥中砷、铬、锰在一次前处理中制备成试液,比色法分析。试验表明,用H2SO4-H3PO4-H2O2进行前处理是可行的。方法简单、挥发酸雾少,用标准参考物质检验证明,分解完全,数据准确,有粒较好一致性。  相似文献   

15.
This paper presents the chemical speciation and retention behavior of chromium (Cr), nickel (Ni), and cadmium (Cd) prior to and after the electrokinetic remediation in glacial till soil. The speciation of the metals was predicted using the chemical speciation program MINEQL+. The simulations were performed for single-contaminant with only Cr(VI) or Ni, and multi-contaminants consisting of: (1) Cr(VI), Ni, and Cd; (2) Cr(III), Ni and Cd; (3) Cr(VI), Cr(III), Ni and Cd; (4) Cr(VI), Ni, and Cd with reducing agents; and (5) Cr(III), Ni, and Cd with oxidizing agent (Mn). The results showed that the speciation and distribution of cationic metals [Ni, Cd, and Cr(III)] in glacial till soil remain unaffected or slightly affected during electrokinetics. This is attributed to the high pH buffering capacity of the glacial till, leading the metals to precipitate in the soil prior to and after electrokinetics. This study showed that during electrokinetics, Cr(VI) existed as anionic complex and migrated towards the anode and the migration is maximum in case of a single-contaminant system. The study also showed that near the anode in the absence of any reducing and oxidizing agent, Cr(VI) mostly adsorbed, and some of Cr(VI) reduced to Cr(III) and migrated towards the cathode and finally precipitated due to high pH conditions. Ni and Cd remain adsorbed or precipitated due to the high pH conditions throughout the soil. Among the reducing agents, the sulfide had significant effect on the migration of metals compared to ferrous ions. While in the presence of oxidizing agent (Mn), no noticeable Cr(VI) was found in the soil sample indicating the reduction of Cr(VI) to Cr(III) and the predominance of reducing conditions due to the presence of naturally occurring iron in the glacial till soil. Overall, this study provides a reasonable explanation of the speciation and distribution of chromium, nickel and cadmium during the electrokinetic remediation of glacial till soil.  相似文献   

16.
We evaluated exposure of aquatic biota to lead (Pb), zinc (Zn), and cadmium (Cd) in streams draining a Pb-mining district in southeast Missouri. Samples of plant biomass (detritus, periphyton, and filamentous algae), invertebrates (snails, crayfish, and riffle benthos), and two taxa of fish were collected from seven sites closest to mining areas (mining sites), four sites further downstream from mining (downstream sites), and eight reference sites in fall 2001. Samples of plant biomass from mining sites had highest metal concentrations, with means 10- to 60-times greater than those for reference sites. Mean metal concentrations in over 90% of samples of plant biomass from mining sites were significantly greater than those from reference sites. Mean concentrations of Pb, Zn, and Cd in most invertebrate samples from mining sites, and mean Pb concentrations in most fish samples from mining sites, were also significantly greater than those from reference sites. Concentrations of all three metals were lower in samples from downstream sites, but several samples of plant biomass from downstream sites had metal concentrations significantly greater than those from reference sites. Analysis of supplemental samples collected in the fall of 2002, a year of above-average stream discharge, had lower Pb concentrations and higher Cd concentrations than samples collected in 2001, near the end of a multi-year drought. Concentrations of Pb measured in fish and invertebrates collected from mining sites during 2001 and 2002 were similar to those measured at nearby sites in the 1970s, during the early years of mining in the Viburnum Trend. Results of this study demonstrate that long-term Pb mining activity in southeast Missouri has resulted in significantly elevated concentrations of Pb, Cd, and Zn in biota of receiving streams, compared to biota of similar streams without direct influence of mining. Our results also demonstrate that metal exposure in the study area differed significantly among sample types, habitats, and years, and that these factors should be carefully considered in the design of biomonitoring studies.  相似文献   

17.
18.
The present study demonstrates comparison of Cr accumulatingpotential by the plants of Najas indica Cham. (submerged),Vallisneria spiralis L. (rooted submerged) and Alternanthera sessilis R. Br. (rooted emergent) under repeatedmetal exposure and its effect on chlorophyll and protein concentrations. These plants were treated with different concentrations of Cr under repeated exposure in controlled laboratory conditions to assess the maximum metal accumulationpotential. The plants of V. spiralis accumulated significantly high amount of Cr under laboratory conditions incomparison to N. indica and A. sessilis. The maximumaccumulation of 1378, 458 and 201 g g-1 dw Cr was found in the leaves of V. spiralis, N. indica and A. sessilis, respectively at 8 mg L-1 after 9 day of Cr exposure. These plants have shown a decrease in chlorophyll andprotein concentrations with increase in Cr concentrations. In view of high accumulation of Cr in V. spiralis, the plantswere treated with different concentrations of tannery effluent collected from Common Effluent Treatment Plant, Unnao (UP). Theplants of V. spiralis treated with 100% tannery wastewatershowed the maximum accumulation (57.5 g g-1 dw) of Cr in the roots after 10 days of exposure. The plants were foundeffective in removing Cr from solution and tannery effluent.  相似文献   

19.
一起河流砷污染事故的处置与监测分析   总被引:2,自引:1,他引:1  
介绍了大沙河砷污染事故的处置和监测分析。多介质排查监测摸清了污染的范围和程度,为治理工作提供了科学依据,污染治理措施有效控制了污染的扩散;监测数据表明,治理措施将水中砷污染物沉降至河床使污染水质达标排放。吸附了大量砷化合物的底泥被清理并进一步处置,多介质跟踪监测应持续进行直至不存在潜在危害。  相似文献   

20.
日本核泄漏事故引发的核危机为人类安全和平地利用核能又一次敲响了警钟.核事故应急工作作为减小核电站危害环境和公众安全的最后屏障,将起到重要的作用,必须做好相关的准备和响应工作.核应急辐射环境监测工作是核应急工作的重要组成部分,在对核应急辐射环境监测进行准备和响应时主要遵循实用性、适用性和适度性并兼顾常规和应急监测的“平战...  相似文献   

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