吹扫—捕集/气相色谱法测定水中挥发性卤代烃

建立了吹扫—捕集 /气相色谱 /电子捕获检测器联用测定水中 5种挥发性卤代烃分析方法 ,且按国家水质分析标准方法 (GB/T 1 71 3 0 -1 997)所确定的三氯甲烷、四氯化碳、三氯乙烯、四氯乙烯、三溴甲烷 5种挥发性卤代烃进行实验 ,采用 Supelcoport担体层析柱对去离子水处理 ,所获得的纯水无色谱干扰峰 ,本法按国家水质分析标准方法列出的 5种挥发性卤代烃进行测定在国内尚未见报导。当纯水的进样体积为 5 .0 ml时 ,其最低检出浓度为 1× 1 0 - 2～ 6× 1 0 - 4(μg/L)之间 ;相对误差在 1 .1 %～ 2 .4%之间 ;加标回收率在 82 .5 %～ 1 0 8%之间 ;相关系数在 0 .9980～ 0 .9999之间。可快速、高灵敏度、简便、准确、精密地测定水中 5种挥发性卤代烃 ,本法适用于饮用水和地表水中挥发性卤代烃的测定     

吹扫-捕集气相色谱法测定水中挥发性卤代烃

研究建立了利用吹扫—捕集气相色谱法测定水中挥发性卤代烃的分析方法,并利用该方法对不同水体中的该类物质进行了测定。当水样体积为５ｍｌ时,９种卤代烃的最低检出浓度为２．８６×１０－３～９．７７×１０－２ｐｐｂ。     

水中挥发性卤代烃的测定——液上气相色谱法

本文探讨了液上气相色谱分析中气液相比、平衡温度,液上气体压力不平衡时间等诸因素对测定的影响,改进了实验技术。 本文参考有关文献,探讨了液上气相色谱法测定水中挥发性卤代烃的影响因素,改进了实验技术。方法已用于地面水及自来水中挥发性卤代烃的测定,变异系数为3.3～10.6％。     

水中九种挥发性卤代烃的气相色谱测定

挥发性卤代烃的分析,一般采用OV-101或SE-30填充柱或毛细管柱液上气相色谐法进行分析测定,其色谱出峰次序主要根据沸点高低,现有文献对沸点相近或相同的色谱分离较困难的物质对如三氯乙烯与一溴二氯甲烷共存时的测定,报道不多见.本文在前人工作的基础上,通过改变色谱     

顶空-气相色谱-质谱法测定土壤中卤代烃

建立顶空-气相色谱-质谱法同时测定土壤中挥发性及半挥发性卤代烃的方法。实验优化顶空平衡温度、顶空平衡时间及盐度条件,并对优化后方法的线性、检出限、精密度及回收率进行分析。结果表明:29种目标化合物在线性范围内线性良好,相关系数均大于0.997,方法检出限为2.2~5.9μg/kg,样品不同浓度水平加标回收率范围为80.0%~120%,相对标准偏差小于20%。该方法适用于土壤样品中挥发及半挥发性卤代烃的测定。     

乌鲁木齐市饮用水中挥发性卤代烃污染调查通过鉴定

由乌鲁木齐市环境科研监测中心站承担的《乌鲁木齐市饮用水中挥发性卤代烃污染调查》研究课题,于1998年2月19日在乌鲁木齐市通过了市科委主持的专家鉴定。本课题研究了乌鲁木齐市饮用水中挥发性卤代烃的种类及其含量、分布特点、污染水平,找出了其变化规律,并对卤代烃的污染     

挥发性卤代烃地表水环境样品保存方法研究

针对国内外监测技术规范对挥发性卤代烃样品保存条件不一致的问题,开展不同因素对挥发性卤代烃样品保存的影响研究。结果表明,调节pH≤2可使水样中挥发性卤代烃的损失率减少2%~25%;在水样中加入抗坏血酸或硫代硫酸钠可减少目标物的损失率约10%。挥发性卤代烃样品的最佳保存条件:加盐酸调节水样pH≤2,加10%硫代硫酸钠或抗坏血酸除余氯(有余氯时),冷藏,14 d内完成测试。在实际工作中,对未受余氯影响的集中式饮用水源地水样,特别是水库水样,若能在2 d内完成测试,在冷藏保存的条件下,可以考虑不调节pH,不添加固定剂。     

固相微萃取-毛细管气相色谱法快速同步分析水中挥发性卤代烃及氯苯类化合物

固相微萃取是一种快速、简便、集萃取浓缩进样于一体的样品前处理技术,具有分析时间短、灵敏度高、无需有机溶剂的优点.本工作用固相微萃取富集水中挥发性卤代烃、氯苯类化合物,毛细管气相色谱分离分析,整个分析过程只需20min,检出限可达0.01～0.3μg/L,已用于自来水、地面水源中挥发性卤代烃、氯苯类化合物含量的测定.     

顶空气相色谱质谱法测定土壤中挥发性卤代烃方法研究

采用顶空气相色谱质谱法(HS/GC-MS)对土壤中挥发性卤代烃进行了测定,优化了分析的顶空条件、气相色谱质谱分离条件。在优化条件下成功实现了24种挥发性卤代烃的分离,确定了分析方法的检出限、测定下限、精密度及回收率等质量控制参数。方法的检出限为0.8~4.4μg/kg,测定下限为3.2~17.6μg/kg。当加标量为100μg/kg和250μg/kg时,相对标准偏差分别为1.3%~12.6%和2.6%~8.7%,加标回收率分别为71.4%~126%和63.1%~121%。     

顶空毛细管柱气相色谱法测定水中卤代烃的研究

以顶空气相色谱法测定水中四种卤代烃,采用电子捕获检测器(ECD),内标法定量。探讨了色谱柱、热浴温度、平衡时间对测定结果的影响。结果表明,采用DB-624色谱柱,样品热浴温度为80℃,平衡时间为60min时,各卤代烃测定效果好。方法检出限为0.15~0.28μg·L-1,回收率在96.8%~99.3%之间,相对标准偏差在3.78%~5.62%之间。该法具有操作简单,准确度、灵敏度较高的特点,可用于水中卤代烃的测定。     

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.     

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.     

Biomonitoring of Lead, Zinc, and Cadmium in Streams Draining Lead-Mining and Non-Mining Areas, Southeast Missouri, USA

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.     

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.