Quantitative determination of fluorotelomer sulfonates in groundwater by LC MS/MS

Aqueous film-forming foams (AFFF) are complex mixtures containing fluorocarbon- and hydrocarbon-based surfactants that are used to fight hydrocarbon-fueled fires. The military is the largest consumer of AFFF in the United States, and fire-training activities conducted at military bases have led to groundwater contamination by unspent fuels and AFFF chemicals. A direct-injection, liquid-chromatography tandem mass spectrometry (LC MS/MS) method was developed to quantify a suite of fluorotelomer sulfonate surfactants in groundwater collected from military bases where fire-training activities were conducted. The 4:2, 6:2, and 8:2 fluorotelomer sulfonates were detected and quantified in groundwater from two of the three military bases. The total fluorotelomer sulfonate concentrations observed at Wurtsmith AFB, MI, and Tyndall AFB, FL, ranged respectively from below quantitation (< or = 0.60) to 182 microg/L and from 1100 to 14,600 microg/L. Analyses of a fluorotelomer-based AFFF concentrate by negative ion fast atom bombardment/mass spectrometry and LC MS/MS analyses indicate that the AFFF concentrate contains only a small amount of fluorotelomer sulfonates and that fluoroalkylthioamido sulfonates are the main anionic fluorosurfactant in the mixtures. More research is needed to determine the fate of fluoroalkylthioamido sulfonates in the environment.     

Identifying the sources of subsurface contamination at the Hanford Site in Washington using high-precision uranium isotopic measurements

In the mid-1990s, a groundwater plume of uranium (U) was detected in monitoring wells in the B-BX-BY Waste Management Area at the Hanford Site in Washington. This area has been used since the late 1940s to store high-level radioactive waste and other products of U fuel-rod processing. Using multiple-collector ICP source magnetic sector mass spectrometry, high-precision uranium isotopic analyses were conducted of samples of vadose zone contamination and of groundwater. The isotope ratios 236U/238U, 234U/238U, and 238U/235U are used to distinguish contaminant sources. On the basis of the isotopic data, the source of the groundwater contamination appears to be related to a 1951 overflow event at tank BX-102 that spilled high-level U waste into the vadose zone. The U isotopic variation of the groundwater plume is a result of mixing between contaminant U from this spill and natural background U. Vadose zone U contamination at tank B-110 likely predates the recorded tank leak and can be ruled out as a significant source of groundwater contamination, based on the U isotopic composition. The locus of vadose zone contamination is displaced from the initial locus of groundwater contamination, indicating that lateral migration in the vadose zone was at least 8 times greater than vertical migration. The time evolution of the groundwater plume suggests an average U migration rate of approximately 0.7-0.8 m/day showing slight retardation relative to a groundwater flow of approximately 1 m/day.     

辣椒制品中大红粉的筛查及检测

采用自制的微型GPC柱对辣椒制品中的非食用色素进行筛查,筛选到一种未知的脂溶性非食用色素,采用紫外可见光谱法、高效液相色谱法、液相色谱-质谱/质谱法及液相色谱-飞行时间质谱法对该未知色素与市售化工染料大红粉进行比较分析,发现该未知色素为大红粉(Pigment Scarlet Powder).为了有效开展食品中大红粉的检测,建立了一种直接溶剂提取法对辣椒制品中大红粉进行检测的方法,该方法操作简便,可实现对辣椒制品中大红粉的快速检测,并在部分辣椒制品中检出大红粉.     

Is indirect exposure a significant contributor to the burden of perfluorinated acids observed in humans?

In comparison to other persistent organic pollutants, human fluorochemical contamination is relatively complicated. This complication arises at least in part from a disparity between the chemicals used commercially and those measured in the environment and humans. Commercial fluorochemical products are dominated by fluorinated polymers used in textile or carpet applications, or fluorosurfactants used in applications ranging from personal care products, leveling and wetting agents, to greaseproofing food-contact materials. Investigations into environmental and human fluorochemical contamination have focused on perfluorinated acids (PFAs), either the perfluorinated carboxylates (PFCAs) or sulfonates (PFSAs). In this review we will present an overview of data related to human fluorochemical exposure including a discussion of fluorochemical production, concentrations in exposure media, biotransformation processes producing PFAs, and trends in human sera. These data will be presented in the context of how they can inform sources of human PFA contamination, specifically whether the contamination results from direct PFA exposure or indirect exposure via the biotransformation of commercial fluorochemicals or their residuals. Concentrations of both perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) began to decrease in human sera around the year 2000, a change that mirrored the 2000-2002 phase-out of perfluorooctane sulfonyl fluoride (POSF) production. These temporal trends suggest exposure to current-use POSF-based materials was a significant source of PFOA and PFOS exposure prior to 2000. Relatively slow PFOA elimination and increasing concentrations of the C9 and C10 PFCAs in human sera suggest continued PFCA exposure, without similar exposure to PFOS, which is consistent with indirect exposure via the biotransformation of fluorotelomer-based materials. Conversely, human exposure models have suggested direct exposure to PFAs present in food items is the major source of human contamination. The data set presented here cannot unequivocally delineate between direct and indirect human exposure, however temporal trends in human sera and exposure media are consistent with indirect exposure representing a significant portion of observed human PFA contamination.     

Measurement of helium isotopes in soil gas as an indicator of tritium groundwater contamination

The focus of this study was to define the shape and extent of tritium groundwater contamination emanating from a legacy burial ground and to identify vadose zone sources of tritium using helium isotopes (3He and 4He) in soil gas. Helium isotopes were measured in soil-gas samples collected from 70 sampling points around the perimeter and downgradient of a burial ground that contains buried radioactive solid waste. The soil-gas samples were analyzed for helium isotopes using rare gas mass spectrometry. 3He/4He ratios, reported as normalized to the air ratio (RA), were used to locate the tritium groundwater plume emanating from the burial ground. The 3He (excess) suggested that the general location of the tritium source is within the burial ground. This study clearly demonstrated the efficacy of the 3He method for application to similar sites elsewhere within the DOE weapons complex.     

Effect of surfactants on the survival and sorption of viruses

There is an increasing concern about the protection of groundwater from contamination by enteric viruses and the prevention of outbreaks of waterborne diseases. Knowledge of survivability and transport of viruses from their point of origin is necessary to determine their potential effects on the neighboring groundwater systems. The distribution of virus is, in turn, dependent on the physical and chemical compositions of the surrounding soil and subsurface systems. For the present study, we have determined the effects of different surfactants (cationic, anionic, nonionic, and biological) and natural organic matter (NOM) on bacteriophages. Results indicated that surfactants and NOM adversely affect phage survival in binary systems, with surfactants being the most harmful. Studies with ternary systems also showed that the presence of surfactants reduced sorption of phages on sorbents either by occupying available sorption sites on the sorbent material or by displacing the sorbed phages from the sorbent surface. Water contact angles of the selected phages and different sorbent surfaces have been measured. Experimental data demonstrated that the sorption of hydrophobic viruses was favored by hydrophobic sorbents, while the sorption of hydrophilic viruses was favored by hydrophilic sorbents.     

Quantitative characterization of trace levels of PFOS and PFOA in the Tennessee River

Although there is evidence of widespread distribution of organic fluorochemicals such as perfluorooctane sulfonate and perfluorooctanoate, in the environment, the versatility of these compounds in industrial and commercial applications complicates characterization of pathways into the environment. A solid-phase extraction method coupled with HPLC-negative-ion electrospray tandem mass spectrometry was developed to quantitatively measure trace levels of organic fluorochemicals in drinking water and surface water. Using this method, certain fluorochemicals can be quantitatively measured in water samples down to 25 ppt, a level well below calculated drinking water advisory levels. To assess fluorochemical distribution in a localized geography and to ascertain whether fluorochemical manufacturing facilities contribute to environmental levels of fluorochemicals, 40 water samples were collected on an 80-mi stretch of the Tennessee River, near a fluorochemical manufacturing site in Decatur, AL. Low levels (ppt) of perfluorooctane sulfonate were determined throughout the stretch of river sampled. Concentrations of the measured fluorochemicals increased downstream of the fluorochemical manufacturing facility, indicating that effluent from manufacturing is one likely source of organic fluorochemicals into the river.     

Thermal degradation products of wood

Thermal degradation products of woods arising at 450°C have been separated by gas chromatography on a DB-1701 capillary column. GC retention times and mass spectral data of 104 polysaccharide derived pyrolysis products are tabulated. The elemental composition of 76 identified compounds are also presented. The mass spectra were obtained by electron impact ionization (EI). However, the molecular mass of all degradation products with Mw>76 was determined by chemical ionization (CI) using iso-butane as reagent gas. The peak assignment was proved in 38 cases by mass spectrometry of authentic compounds and 32 degradation products were identified according to the literature. The spectral data are presented as a Mass Peak Index showing the intensity of the nine most abundant peaks.     

化学计量学法对紫苏叶与紫苏子挥发油共有组分分析

采用气相色谱-质谱(GC-MS)法分离测定紫苏叶与紫苏子挥发油成分,利用化学计量学解析法对重叠的色谱峰进行解析,得到各组分的纯色谱曲线和质谱,通过质谱库对解析的纯组分进行定性,紫苏叶挥发油的定性组分74个,占总含量的98.56%;紫苏子挥发油的定性组分85个,占总含量的97.92%。结果表明,紫苏叶与紫苏子挥发油共有组分数45个,分别占鉴定组分数的60.81%、52.94%;占鉴定组分量的66.38%、84.30%。相对含量较高的组分是柠檬烯、4,11,11-三甲基-8-亚甲基二环十一碳烯、2,6-二甲基-6-(4-甲基-3-戊烯基)双环庚-2-烯、石竹烯氧化物、1-(2-呋喃)-戊酮、3,6-二乙基-3,6-二甲基-三环己烷。     

Comparison of selection methods to deduce natural background levels for groundwater units

Establishment of natural background levels (NBL) for groundwater is commonly performed to serve as reference when assessing the contamination status of groundwater units. We compare various selection methods to establish NBLs using groundwater quality data for four hydrogeologically different areas in the highly populated and developed subcatchment Western River Rhine, The Netherlands: selection of old groundwater (before 1945), of tritium-free groundwater (i.e., infiltrated before 1950), and of groundwater having no agricultural contamination by NO3 and SO4. Differences as well as similarities in percentile values for Cl, NH4, and SO4 concentrations are observed among the selection methods as well as the spatial units, pointing out that selection of the data setis a crucial step in deducing NBLs. The following general points of attention are deduced: (1) reference to composition of recharge water (rain or river infiltrate) is necessary to confirm the statistical outcomes, (2) old analyses are affected by conservation errors after sampling for redox-sensitive solutes and may be obtained by selective sampling, (3) old analyses are the only direct reference for NBLs for groundwater units having only anthropogenically influenced, young groundwater at present, and (4) establishment of a priori percentile values as maximum NBL is not right and confirmation by additional process-based insight in the controls on water composition is necessary.     

基于UPLC-Orbitrap-HRMS技术的苎麻籽乙醇提取物中主要化学成分分析与鉴定

应用超高效液相色谱-离子阱-超高分辨率质谱技术对苎麻籽乙醇提取物主要化学成分进行了分析与鉴定.高效液相色谱条件为Agilent 5TC-C18色谱柱(4.6 mm×250 mm,5μm)、0.2％甲酸水溶液-乙腈作为流动相梯度洗脱.质谱条件为电喷雾离子源(ESI),离子阱质量分析器(orbitrap),喷雾电压3500...     

Characterization of Brazilian green propolis throughout the seasons by headspace GC/MS and ESI-MS

BACKGROUND: A screening of the chemical composition of eight commercial classes of raw Brazilian green propolis throughout the seasons was carried out. A multivariate exploratory analysis of chemical composition obtained by gas chromatography associated with mass spectrometry with headspace extraction (HS‐GC/MS), and by mass spectrometry with electrospray ionization (ESI‐MS) was carried out using principal component analysis (PCA). RESULTS: Differences in the volatile and polyphenolic profiles of propolis samples were verified during the seasons. Within each season, the high quality commercial classes of propolis presented similar characteristics, while the low quality classes presented distinct compositions. In spring and summer, propolis of the trimming class, commonly considered of low quality by beekeepers, presented a composition similar to the superior quality propolis. CONCLUSION: Seasonality influences the chemical composition of the commercial classes of raw Brazilian green propolis. Headspace‐GC/MS and ESI‐MS assisted by PCA are effective to characterize volatile and non‐volatile compounds of the propolis samples, and to correlate it to the seasons. Copyright © 2011 Society of Chemical Industry     

两种方法提取降香黄檀籽挥发油的成分分析

采用同步蒸馏萃取和超声波辅助石油醚浸提两种方法提取降香黄檀籽挥发油,气象色谱-质谱联用法进行化学成分分析,分别鉴定出31种和81种化合物。同步蒸馏萃取法提取的挥发油主要成分为p,p,p-三苯基-亚胺磷（35．3％）、二（1-甲基乙基）过氧化物（16．4％）、1-甲基-1H-吡咯（5．2％）和3,3,6-三甲基-1,5-庚二烯-4-酮（4．7％）等;超声波辅助石油醚浸提法提取的挥发油主要成分有a-氢过氧基二乙醚（28．7％）、11,14-二烯二十酸甲酯（6．3％）、棕榈酸（5．5％）和γ-生育酚（5．4％）等。     

Susceptibility of residential wells to VOC and nitrate contamination

Water quality of residential wells is vital to public health and a complex issue for regulatory agencies. South Carolina, a typical southeastern rural state, has no required testing of residential well water quality after initial well construction. This study used site-selection criteria to identify susceptible residential wells based on a combination of geologic vulnerability and potential contaminant loading. Geologic vulnerability was defined as increased probability of contaminants being transported from the land surface into the groundwater based on geological properties. As a surrogate for potential general contaminant loading, wells were located within 800 m of an EPA Toxics Release Inventory facility reporting VOC emissions, thus sampling was nonrandom. Seventy private residential wells were sampled for volatile organic compounds (VOCs) and nitrate-nitrogen (NO3-N) and analyzed using gas chromatography/mass spectrometry and the cadmium reduction method, respectively. Geographic Information Systems (GIS) was used to quantify four explanatory variables that affect well susceptibility to nitrate: population density, land cover, local relief (percent slope), and soil texture. VOCs were detected in 11 wells, and two sites exceeded the MCL for 1,1-dichloroethylene (36.1 microg/L) and trichloroethylene (9.0 microg/L). Elevated NO3-N (defined as > or = 1.0 mg/L) was measured in 20 wells. Logistic regression identified grassland/cultivated land cover as a variable that significantly increased the probability of NO3-N contamination (p = 0.003). Using easily accessible databases to identify factors that increase the probability of groundwater pollution could lead to more effective programs for locating residential wells that are susceptible to contamination. Increased monitoring of well water quality, as is being considered in some states, is warranted to reduce potential human exposure to contaminated drinking water.     

Measurements of isoprene-derived organosulfates in ambient aerosols by aerosol time-of-flight mass spectrometry - part 1: single particle atmospheric observations in Atlanta

Organosulfate species have recently been identified as a potentially significant class of secondary organic aerosol (SOA) species, yet little is known about their behavior in the atmosphere. In this work, organosulfates were observed in individual ambient aerosols using single particle mass spectrometry in Atlanta, GA during the 2002 Aerosol Nucleation and Characterization Experiment (ANARChE) and the 2008 August Mini-Intensive Gas and Aerosol Study (AMIGAS). Organosulfates derived from biogenically produced isoprene were detected as deprotonated molecular ions in negative-ion spectra measured by aerosol time-of-flight mass spectrometry; comparison to high-resolution mass spectrometry data obtained from filter samples corroborated the peak assignments. The size-resolved chemical composition measurements revealed that organosulfate species were mostly detected in submicrometer aerosols and across a range of aerosols from different sources, consistent with secondary reaction products. Detection of organosulfates in a large fraction of negative-ion ambient spectra - ca. 90-95% during ANARChE and ~65% of submicrometer particles in AMIGAS - highlights the ubiquity of organosulfate species in the ambient aerosols of biogenically influenced urban environments.     

Perfluorinated compounds in the environment and the blood of residents living near fluorochemical plants in Fuxin, China

A fluorochemical industrial park was built in 2004 in Fuxin, China, for the production of polytetrafluoroethylene (PTFE) and perfluorobutane sulfonate (PFBS). Yet little is known about the distribution of fluorochemicals in the environment and in people living in and around the park. In this study, environmental samples were collected from 22 sites in Fuxin to investigate the extent of perfluorinated compound (PFC) contamination in the environment around the park, and in drinking water from the public water supply system and groundwater in shallow aquifers from private wells near the park. Serum samples were also collected from nonoccupationally exposed residents living in Fuxin to determine the PFC load of local residents. As the dominant contaminant of eight target PFCs, the maximum concentrations of perfluorooctanoic acid (PFOA) in sediment and river water of the River Xi along the industrial park were 48 ng/g dry weight and 668 ng/L, respectively; the highest PFOA concentration in groundwater beneath the park was 524 ng/L; and the PFOA levels in drinking water from the public water supply system ranged between 1.3 and 2.7 ng/L. In human serum, PFOA had the geometric mean at 4.3 ng/mL, ranging from 0.02 to 93 ng/mL. This study serves to document what should be the beginning of a long-term surveillance effort to minimize potential exposure of residents living in Fuxin.     

新疆芳香和帕米尔新塔花精油组成及其抗氧化的研究

优化水蒸气蒸馏法提取新疆芳香和帕米尔两种新塔花挥发油的最佳条件,利用气相色谱- 质谱联用技术分析两种新塔花挥发油的化学成分和组成,研究两种新塔花挥发油的抗氧化能力。从芳香新塔花的地上部分提取的挥发油中分离鉴定出10 种成分,占挥发油总量的99.7% 以上。芳香新塔花的主要成分为长叶薄荷酮(80.7%)、薄荷酮(8.3%)、胡椒烯酮(4.9%)及异薄荷酮(2.6%)。从帕米尔新塔花的地上部分提取的挥发油中分离鉴定出29 种成分,占挥发油总量的99.8% 以上。帕米尔新塔花精油中主要含有长叶薄荷酮(45.9%)、异薄荷酮(24.1%)、(+)- 新薄荷醇(10.1%)和百里香酚(9.4%)。通过与百里香酚,VC 和BHT 的对比,新塔花精油具有一定的抗氧化能力,能够有效清除DPPH·,超氧阴离子自由基和羟自由基;能够保护脂质体,抑制其过氧化;并且具有明显的清除亚硝酸盐的作用。结果表明,帕米尔新塔花精油的抗氧化效果优于芳香新塔花精油。     

Enhanced soil washing of phenanthrene by mixed solutions of TX100 and SDBS

Increased desorption of hydrophobic organic compounds (HOCs) from soils and sediments is a key to the remediation of contaminated soils and groundwater. In this study, phenanthrene desorption from a contaminated soil by mixed solutions of a nonionic surfactant(octylphenol polyethoxylate, TX100) and an anionic surfactant (sodium dodecylbenzenesulfonate, SDBS) was investigated. Phenanthrene desorption depended on not only aqueous surfactant concentrations and phenanthrene solubility enhancement but also the soil-sorbed surfactant amount and the corresponding sorption capacity of sorbed surfactants. The added surfactant critical desorption concentrations (CDCs) for phenanthrene from soil depended on both sorbed concentrations of surfactants and their critical micelle concentrations (CMCs). Phenanthrene desorption by mixed solutions was more efficient than individual surfactants due to the low sorption loss of mixed surfactants to soil. Among the tested surfactant systems, mixed TX100 and SDBS with a 1:9 mass ratio exhibited the highest phenanthrene desorption. Mixed micelle formation, showing negative deviation of CMCs from the ones predicted by the ideal mixing theory, was primarily responsible for the significant reduction of soil-sorbed amounts of TX100 and SDBS in their mixed systems. Therefore, mixed anionic-nonionic surfactants had great potential in the area of enhanced soil and groundwater remediation.     

Chlorinated ethene source remediation: lessons learned

Chlorinated solvents such as trichloroethene (TCE) and tetrachloroethene (PCE) are widespread groundwater contaminants often released as dense nonaqueous phase liquids (DNAPLs). These contaminants are difficult to remediate, particularly their source zones. This review summarizes the progress made in improving DNAPL source zone remediation over the past decade, and is structured to highlight the important practical lessons learned for improving DNAPL source zone remediation. Experience has shown that complete restoration is rare, and alternative metrics such as mass discharge are often useful for assessing the performance of partial restoration efforts. Experience also has shown that different technologies are needed for different times and locations, and that deliberately combining technologies may improve overall remedy performance. Several injection-based technologies are capable of removing a large fraction of the total contaminant mass, and reducing groundwater concentrations and mass discharge by 1 to 2 orders of magnitude. Thermal treatment can remove even more mass, but even these technologies generally leave some contamination in place. Research on better delivery techniques and characterization technologies will likely improve treatment, but managers should anticipate that source treatment will leave some contamination in place that will require future management.     

Do ponds cause arsenic-pollution of groundwater in the Bengal basin? An answer from West Bengal

We report time-series data collected over two years for delta18O, delta2H, and Ca, Mg, K, and Cl, concentrations for 10 ponds in, and upflow of, an As-polluted region of southern West Bengal. We compare the compositions of As-polluted groundwaters from wells with the compositions of waters in ponds upflow, and within the range of influence, of the wells. Conservative tracers (delta18O, delta2H, K), and other tracers (Ca, Mg) that are likely conservative in the waters, showthat pondwater and groundwater are distinct and do not overlap in composition. These data show that water from ponds cannot be identified in As-polluted groundwater, so putative DOC in pondwater cannot be mixing into the As-polluted groundwater we have sampled. Separate estimates of the degree of recharge from ponds to groundwater, using calculations based on temporal variations in salt content and isotopic composition in ponds, and salt-balance, show that insignificant amounts of As-polluted groundwater are derived via pond recharge. It follows that pondwater in the study area does not contribute significant mass to arsenic-polluted groundwater and so does not provide organic matterto aquifers in amounts sufficientto drive reduction of iron oxyhydroxides and hence arsenic pollution.