分光光度法测定水中十六烷基三甲基溴化铵

基于甲基橙(MO)在水体中和阳离子表面活性剂发生的褪色反应,采用分光光度法测定十六烷基三甲基溴化铵(CTAB),优化了试验条件,讨论了干扰物质的影响。MO与CTAB在10%乙醇-水溶液中反应形成淡黄色离子缔合物,以MO的最大吸收波长470 nm为测定波长,CTAB质量浓度在0 mg/L～13.1 mg/L范围内遵守朗伯-比尔定律,吸光系数为17.48 L/(g.cm),方法检出限为0.364 mg/L,标准溶液平行测定的RSD为2.3%,样品加标回收率为91.8%～107%。     

氨基黑10B褪色光度法测定痕量季铵盐型阳离子表面活性剂的研究

研究了在硫酸介质中,季铵盐型表面活性剂溴化十六烷基三甲基铵(CTMAB)、溴化十六烷基吡啶(CPB)对氨基黑10B的褪色作用,建立了褪色光度法测定痕量CTMAB和CPB的新方法,并探讨了褪色反应的机理和条件,测定CTMAB和CPB的线性范围皆为0～3×10-5mol L,摩尔吸光系数分别为1 77×104L mol·cm和1 17×104L mol·cm,用于水样中微量季铵盐型表面活性剂的测定,结果满意。     

DPD分光光度法测定水中游离余氯的探讨

采用DPD分光光度法测定水中的游离余氯，验证了用高锰酸钾替代氯制剂配制标准溶液的有效性，方法在0 mg/L～0.800 mg/L范围内符合朗伯-比尔定律，检出限为0.01 mg/L。使用次氯酸钠标准体系和高锰酸钾标准体系分别测定废水样品及其加标样，并用硫酸亚铁铵滴定法作比对验证，结果显示3种方法具有可比性。     

高碘酸钾氧化甲酚红催化动力学光度法测定水中痕量锰

研究了在氢氧化钠介质中,锰强烈催化高碘酸钾氧化甲酚红的褪色反应,建立了高碘酸钾氧化甲酚红催化动力学光度法测定水中痕量锰的新方法,优化了试验条件,讨论了共存离子的影响。方法最大吸收波长为570 nm,在0.020 mg/L~0.200 mg/L范围内线性良好,检出限为0.005 mg/L,水样平行测定的RSD≤2.2%,加标回收率为97.9%~101%。     

溴百里酚蓝测定水中余氯的方法研究

提出了测定水中余氯的一个新方法.余氟将溴百里酚蓝氧化而褪色,在碱性介质中为蓝色.λmax=616nm,ε=9.17×104L/mol·cm.检出限(4.6SD)为0.6mg/L.用于测定自来水中余氯,相对标准偏差为1.76%,加标回收率为97.22%～104.2%.     

催化光度法测定鸡蛋中的碘

研究了在 80～ 1 0 0℃条件下制备样品 ,利用催化光度法间接测得鸡蛋中碘的含量。在 0～ 0 .0 2 1 mg/ L内符合比耳定律 ,摩尔吸光系数达 2 .0 3× 1 0 5L.mol- 1 .cm- 1。可用于其它食品中微量碘的测定。     

甲基蓝褪色分光光度法测定 NO -2 - N

《水和废水监测分析方法》(第 3版 )中测定水样ＮＯ-2 -Ｎ采用Ｎ - ( 1 -萘基 ) -乙二胺分光光度法和离子色谱法。如用甲基蓝测定ＮＯ-2 -Ｎ ,利用ＮＯ-2 在酸性介质中使甲基蓝褪色的反应原理 ,在最大吸收波长 60 3ｎｍ处 ,褪色程度随ＮＯ-2 浓度增加而变浅 ,从而建立测定ＮＯ-2 -Ｎ的新方法[1 ] 。1　试验1 1　主要仪器与试剂Ｆ 72 1分光光度计 ;0 2 5ｍｇ/ｍＬＮＯ-2 -Ｎ标准储备液 ,置冰箱内保存 ;1ｍｇ/ＬＮＯ-2 -Ｎ标准使用液 ,使用当天配制 ;4× 1 0 - 5 ｍｏｌ/Ｌ甲基蓝溶液 ;0 2 5ｍｏｌ/Ｌ盐酸溶液。1 2　测定步骤1 2 1　标…     

褪色光度法测定微量碘的研究

研究了在硫酸介质中、溴化钾催化下 ,碘酸根氧化酸性铬蓝K褪色的最佳条件。其最大吸收波长λmax为 5 2 0nm ,表观摩尔吸光系数为 1 .1× 1 0 4 L·mol- 1·cm- 1,碘浓度在 0～ 3 .6mg/L内呈线性关系。方法用于测定加碘食盐中的碘 ,结果令人满意     

水中总磷和溶解性磷酸盐的快速分光光度法

在H_2SO_4溶液介质中,磷钼钒三元杂多酸与孔雀绿反应形成有色络合物,在波长620nm处表观摩尔吸光系数为1.73×10~5L/mol·cm,线性范围是0～0.4(mg/L).检测下限为0.016mg/L,方法准确、稳定,操作简便、快速.能够用于水中总磷和溶解性磷酸盐的测定.     

火焰原子吸收法测定饮用水中银的改进

对火焰原子吸收分光光度法测定饮用水中银的方法作了改进。试验发现在酸性条件下,不利于银的测定,改加氨水氰化钾溶液则取得满意的结果,提高了测定灵敏度。银的特征质量浓度为0 016mg·L-1/1%吸收,检测限为0 001mg/L,相对标准差<2.5%,加标回收率在98%～103%之间。     

A New Mathematical Approach in Environmental and Life Sciences: Gene–Environment Networks and Their Dynamics

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.      

An investigation on biological stability of product water generated by lab-scale and pilot-scale distillation systems

Material Disposal Area G is the primary low-levelradioactive waste disposal site at Los Alamos NationalLaboratory, New Mexico, and is adjacent to Pueblo of SanIldefonso lands. Pueblo residents and Los Alamos scientists areconcerned about radiological doses resulting from uptake of AreaG radionuclides by mule deer (Odocoileus hemionus) andRocky Mountain elk (Cervus elaphus), then consumption ofdeer and elk meat by humans. Tissue samples were collected fromdeer and elk accidentally killed near Area G and were analyzedfor ³H, ⁹⁰Sr, total U, ²³⁸Pu, ^{239, 240}Pu,²⁴¹Am, and ¹³⁷Cs. These data were used to estimatehuman doses based on meat consumption of 23 kg y^-1. Humandoses were also modeled using RESRAD, and dose rates to deer andelk were estimated with a screening model. Dose estimates tohumans from tissue consumption were 2.9 × 10^-3 mSv y^-1and 1.6 × 10^-3 mSv y^-1 from deer and elk, respectively,and RESRAD dose estimates were of the same order of magnitude. Estimated dose rates to deer and elk were 2.1 × 10^-4 mGyd^-1 and 4.7 × 10^-4 mGy d^-1, respectively. Allestimated doses were significantly less than established exposurelimits or guidelines.     

Assessing health consequences in an environmental impact assessment: The case of Amsterdam Airport Schiphol

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.     

Contaminant Profiles of Two Species of Shorebirds Foraging Together at Two Neighboring Sites in South San Francisco Bay, California

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).     

土壤和底泥中砷、铬、锰测定的前处理技术

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。     

Metal concentrations in deciduous tree leaves from urban areas in Poland

Accumulation of metals in deciduous tree foliage fromurban areas in western-south Poland was monitored duringthe vegetation season of 2000 year. Concentrations of Al,Ba, Ca, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Sr, Ti and Znwere measured in birch, willow, linden and maple leavesusing the ICP-AES method. Seasonal variations of metalconcentrations and their relations with sampling sitewere investigated. The most dynamic accumulation of Al,Cd, Cr, Ni and Pb was observed for examined species. Thehighest differences in element concentrations forinvestigated sites were found for Ba, Cd, Mn and Ni.Interelement correlations were investigated. In allfoliar samples synergistic relationships between Al–Crand Ca-Sr were found. Statistically significant negativecorrelations were observed only for Cd and Ti in birch leaves.     

Varying Stable Nitrogen Isotope Ratios of Different Coastal Marsh Plants and Their Relationships with Wastewater Nitrogen and Land Use in New England, USA

The stable nitrogen isotope ratios of some biota have been used as indicators of sources of anthropogenic nitrogen. In this study the relationships of the stable nitrogen isotope ratios of marsh plants, Iva frutescens (L.), Phragmites australis (Cav.) Trin ex Steud, Spartina patens (Ait.) Muhl, Spartina alterniflora Loisel, Ulva lactuca (L.), and Enteromorpha intestinalis (L.) with wastewater nitrogen and land development in New England are described. Five of the six plant species (all but U. lactuca) showed significant relationships of increasing δ ¹⁵N values with increasing wastewater nitrogen. There was a significant (P < 0.0001) downward shift in the δ ¹⁵N of S. patens (6.0 ± 0.48‰) which is mycorrhizal compared with S. alterniflora (8.5 ± 0.41‰). The downward shift in δ ¹⁵N may be caused by the assimilation of fixed nitrogen in the roots of S. patens. P. australis within sites had wide ranges of δ ¹⁵N values, evidently influenced by the type of shoreline development or buffer at the upland border. In residential areas, the presence of a vegetated buffer (n = 24 locations) significantly (P < 0.001) reduced the δ ¹⁵N (mean = 7.4 ± 0.43‰) of the P. australis compared to stands where there was no buffer (mean = 10.9 ± 1.0‰; n = 15). Among the plant species, I. frutescens located near the upland border showed the most significant (R ² = 0.64; P = 0.006) inverse relationship with the percent agricultural land in the watershed. The δ ¹⁵N of P. australis and I. frustescens is apparently an indicator of local inputs near the upland border, while the δ ¹⁵N of Spartina relates with the integrated, watershed-sea nitrogen inputs.     

Radionuclide Concentrations in Benthic Invertebrates from Amchitka and Kiska Islands in the Aleutian Chain, Alaska

Concentrations of 13 radionuclides (¹³⁷Cs, ¹²⁹I, ⁶⁰Co, ¹⁵²Eu, ⁹⁰Sr, ⁹⁹Tc, ²⁴¹Am, ²³⁸Pu, ^239,249Pu, ²³⁴U, ²³⁵U, ²³⁶U, ²³⁸U were examined in seven species of invertebrates from Amchitka and Kiska Islands, in the Aleutian Chain of Alaska, using gamma spectroscopy, inductively coupled plasma mass spectroscopy, and alpha spectroscopy. Amchitka Island was the site of three underground nuclear test (1965–1971), and we tested the null hypotheses that there were no differences in radionuclide concentrations between Amchitka and the reference site (Kiska) and there were no differences among species. The only radionuclides where composite samples were above the Minimum Detectable Activity (MDA) were ¹³⁷Cs, ²⁴¹Am, ^239,249Pu, ²³⁴U, ²³⁵U, ²³⁶U, and ²³⁸U. Green sea urchin (Strongylocentrotus polyacanthus), giant chiton (Cryptochiton stelleri), plate limpets (Tectura scutum) and giant Pacific octopus (Enteroctopus dofleini) were only tested for ¹³⁷Cs; octopus was the only species with detectable levels of ¹³⁷Cs (0.262 ± 0.029 Bq/kg, wet weight). Only rock jingle (Pododesmus macroschisma), blue mussel (Mytilus trossulus) and horse mussel (Modiolus modiolus) were analyzed for the actinides. There were no interspecific differences in ²⁴¹Am and ^239,240Pu, and almost no samples above the MDA for ²³⁸Pu and ²³⁶U. Horse mussels had significantly higher concentrations of ²³⁴U (0.844 ± 0.804 Bq/kg) and ²³⁸U (0.730 ± 0.646) than the other species (both isotopes are naturally occurring). There were no differences in actinide concentrations between Amchitka and Kiska. In general, radionuclides in invertebrates from Amchitka were similar to those from uncontaminated sites in the Northern Hemisphere, and below those from the contaminated Irish Sea. There is a clear research need for authors to report the concentrations of radionuclides by species, rather than simply as ‘shellfish’, for comparative purposes in determining geographical patterns, understanding possible effects, and for estimating risk to humans from consuming different biota.     

Effect of heavy metal contaminated shooting range soils on mycorrhizal colonization of roots and metal uptake by leek

We grew leek (Allium porrum) in soils of two shooting ranges heavily contaminated with heavy metals in the towns of Zuchwil and Oberuzwil in Switzerland as a bioassay to test theactivity of arbuscular mycorrhizal (AM) fungi in these soils.Soil samples were taken from (1) front of the shooting house(HOUSE), (2) the area between house and target (FIELD) and (3) the berm (BACKSTOP). Samples of Ribwort plantain (Plantagolanceolata) growing naturally within the shooting ranges werealso collected and the colonization of its roots by mycorrhizalfungi was measured. The number of AM spores in the soils wassignificantly reduced concomitant with the increase in thedegree of soil contamination with metals. In Zuchwil,mycorrhizal fungi equally colonized roots of Ribwort plantainsampled from BACKSTOP and HOUSE. In Oberuzwil, however, plantsfrom BACKSTOP had lower colonization when compared with thosesampled from HOUSE. Colonization of leek was strongly reducedin the BACKSTOP soil of Zuchwil and slightly reduced in theBACKSTOP soil of Oberuzwil when compared with plants grown inrespective HOUSE soil. Concentrations of Cd, Cr, Cu, Ni, Pb andZn in the leaves of leek grown in the BACKSTOP soil was withinthe range considered toxic for human consumption. This pointsto the high degree of bio-availability of these metal in thesesoils. Significant decrease in the number of mycorrhizal sporesin the BACKSTOP soils in Zuchwil and the low colonization ofleek roots grown in these soils point to possible changes inthe species diversity of mycorrhizal fungi in these soils.     

Geochemical assessment of metal transport in glacial till during electrokinetic remediation

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.