Colon extended physiologically based extraction test (CE-PBET) increases bioaccessibility of soil-bound PAH

Assessment of the risk to human health posed by contaminated land may be seriously overestimated if reliant on total pollutant concentration. In vitro extraction tests, such as the physiologically based extraction test (PBET), imitate the physicochemical conditions of the human gastro-intestinal tract and offer a more practicable alternative for routine testing purposes. However, even though passage through the colon accounts for approximately 80% of the transit time through the human digestive tract and the typical contents of the colon in vivo are a carbohydrate-rich aqueous medium with the potential to promote desorption of organic pollutants, PBET comprises stomach and small intestine compartments only. Through addition of an eight-hour colon compartment to PBET and use of a carbohydrate-rich fed-state medium we demonstrated that colon-extended PBET (CE-PBET) increased assessments of soil-bound PAH bioaccessibility by up to 50% in laboratory soils and a factor of 4 in field soils. We attribute this increased bioaccessibility to a combination of the additional extraction time and the presence of carbohydrates in the colon compartment, both of which favor PAH desorption from soil. We propose that future assessments of the bioaccessibility of organic pollutants in soils using physiologically based extraction tests should have a colon compartment as in CE-PBET.     

木质复合材料及其在室内环境中的应用

主要介绍了木质复合材料的发展现状以及它在室内环境中的应用。木质复合材料是木材工业的发展重点,木质复合材料研究的深度、应用的广度及其发展的速度已成为衡量一个国家木材工业技术水平先进程度的重要标志之一。     

Identification and determination of hexachlorocyclopentadienyl-dibromocyclooctane (HCDBCO) in residential indoor air and dust: a previously unreported halogenated flame retardant in the environment

Hexachlorocyclopentadienyl-dibromocyclooctane (HCDBCO, CAS 51936-55-1) has been detected in residential indoor air and indoor dust in Ottawa, Canada. The positive identification of the chemical was based on the interpretation of the mass spectra of the chemical obtained under both electron impact and negative chemical ionization operation modes, as well as through the synthesis of this chemical. This is the first report on the presence of HCDBCO in the environment. Although the levels of HCDBCO in indoor dust, with a geometric mean of 2.7 ng g(-1) and a median of 2.0 ng g(-1) respectively, are generally low compared to those of polybrominated diphenyl ethers (PBDEs) and dechlorane plus, another recently detected flame retardant, high levels of HCDBCO were detected in several dust samples with a maximum level of 93,000 ng g(-1) which is 16 times higher than the maximum level of the structurally related dechlorane plus. On the other hand, levels of HCDBCO in indoor air, with a geometric mean of 70 pg m(-3) and a median of 92 pg m(-3), were higher than those of the major PBDE congeners. The maximum level of HCDBCO found in indoor air was 3000 pg m(-3). Structurally, HCDBCO belongs to a group of norbornane based halogenated flame retardants. The presence of HCDBCO in the indoor environment may raise awareness of the potential release of this and related flame retardants into the environment during the production and usage of products that contain them, and the potential implications of human exposure to these chemicals as people spend the majority of their time indoors in modern society.     

快速提取装置在酒精度检测中的应用研究

对快速提取装置在酒精度检测中的应用进行了研究。采用DE·2000型快速提取装置去除样品中的不挥发性物质,收集馏出液,再用酒精计法测定样品的酒精度,并将测定结果与国标方法的检测结果及时间进行比较。试验结果表明,DE·2000型快速提取装置适用于酒精体积分数≤45%的酒类中乙醇的提取。该方法检测速度快,结果准确,效率高。     

Hexabromocyclododecanes in indoor dust from Canada, the United Kingdom, and the United States

alpha-, beta-, and gamma-hexabromocyclododecane diastereomers (HBCDs) were measured in house dust from Birmingham, U.K. (n=31, median concentration=730 ng sigmaHBCDs g(-1)); Amarillo/Austin, TX (n=13, 390 ng g(-1)); and Toronto, Canada (n=8, 640 ng g(-1)). Concentrations in dust (n=6, 650 ng g(-1)) from U.K. offices were within the range for UK homes. Concentrations from each country were statistically indistinguishable. In one UK house dust sample, 110,000 ng g(-1) was recorded-the highest recorded in indoor dust to date. While upper bound average U.K. dietary exposures for adults and toddlers, respectively, are 413 and 240 ng sigmaHBCDs day(-1), U.K. adults and toddlers daily ingesting, respectively, 50 and 200 mg of dust contaminated at the 95th percentile concentration are exposed, respectively, to 1100 and 4400 ng sigmaHBCDs day(-1). Normalized to body weight, this high-end exposure scenario estimate for toddlers is within the range reported elsewhere for occupationally exposed adults. While in commercial formulations gamma-HBCD predominates (>80%), alpha-HBCD in dust constitutes 14-67% of sigmaHBCDs (average 32%). Hence the predominance of the alpha-diastereomer in humans may arise partly from dust ingestion, and not solely to in vivo metabolism (when alpha-HBCD is formed from bioisomerization of other diastereomers), or dietary exposure (where alpha-HBCD predominates in most foodstuffs).     

Life tables and a physiologically based model application to Corcyra cephalonica (Stainton) populations

The rice moth Corcyra cephalonica is a harmful insect pest for grains stocked in storage systems. Its infestations represent a serious concern among producers, because of the non-marketability of the products affected by it and subsequent economic losses.New technologies are improving the supply chain of the stored grains, in line with the integrated pest management framework. However, a prompt control action also requires an in-depth knowledge of insect pests’ biology and their response to environmental parameters. If this information is available, it can also be translated into mathematical language. The modelling of insect pest populations is increasing in utility, particularly if the models are included in decision support systems.The aim of this work concerns two aspects of a model application and validation. Since physiologically based models require information about interactions between species and environment, C. cephalonica individuals were reared at different constant temperatures: 18, 21, 24,26, 28, 30,34 and 36 °C. This first part provided the life tables, whose data were used to estimate the parameters of the Logan, Briére, and Sharpe and De Michele development rate functions.The second part of the work concerns the application of a physiologically based model described by a first order partial differential equation. The validation of the simulations was conducted with a semi-field experimentation with three repetitions.Results showed that the life tables are well represented by the Sharpe and De Michele development rate function, and that the physiologically based model proposed is reliable in representing field populations.     

Perfluorinated sulfonamides in indoor and outdoor air and indoor dust: occurrence, partitioning, and human exposure

Perfluorinated alkyl sulfonamides (PFASs) which are used in a variety of consumer products for surface protection were investigated through a comprehensive survey of indoor air, house dust, and outdoor air in the city of Ottawa, Canada. This study revealed new information regarding the occurrence and indoor air source strength of several PFASs including N-methylperfluorooctane sulfonamidoethanol (MeFOSE), N-ethylperfluorooctane sulfonamidoethanol (EtFOSE), N-ethylperfluorooctane sulfonamide (EtFOSA), and N-methylperfluorooctane sulfonamidethylacrylate (MeFOSEA). Passive air samplers consisting of polyurethane foam disks were calibrated and used to conduct the indoor and outdoor survey. Indoor air concentrations for MeFOSE and EtFOSE (1490 and 740 pg m(-3), respectively) were about 10-20 times greater than outdoor concentrations, establishing indoor air as an important source to the outside environment. EtFOSA and MeFOSEA concentrations were lower in indoor air (40 and 29 pg m(-3) respectively) and below detection in outdoor air samples. For indoor dust, highest concentrations were recorded for MeFOSE and EtFOSE with geometric mean concentrations of 110 and 120 ng g(-1), while concentrations for EtFOSA and MeFOSEA were below detection and 7.9 ng g(-1) respectively. MeFOSE and EtFOSE concentrations in house dust followed levels in indoor air. However, resolution of the coupled air and dust data (for the same homes) was not successful using existing KoA-based models for surface-air exchange. The partitioning to house dust was greatly underpredicted. The difficulties with existing models may be due to the high activity coefficient of PFASs in octanol and/or a situation where the dust is greatly oversaturated with respect to the air due to components of the dust being contaminated with PFASs. A human exposure assessment based on median air and dust concentrations revealed that human exposure through inhalation (100% absorption assumed) and dust ingestion were approximately 40 and approximately 20 ng d(-1), respectively. However, for children the dust ingestion pathway was dominant and accounted for approximately 44 ng d(-1).     

Occurrence of eight bisphenol analogues in indoor dust from the United States and several asian countries: implications for human exposure

Bisphenol A has been reported to be a ubiquitous contaminant in indoor dust, and human exposure to this compound is well documented. Information on the occurrence of and human exposure to other bisphenol analogues is limited. In this study, eight bisphenol analogues, namely 2,2-bis(4-hydroxyphenyl)propane (BPA), 4,4'-(hexafluoroisopropylidene)diphenol (BPAF), 4,4'-(1-phenylethylidene)bisphenol (BPAP), 2,2-bis(4-hydroxyphenyl)butane (BPB), 4,4'-dihydroxydiphenylmethane (BPF), 4,4'-(1,4-phenylenediisopropylidene)bisphenol (BPP), 4,4'- sulfonyldiphenol (BPS), and 4,4'-cyclohexylidenebisphenol (BPZ), were determined in indoor dust samples (n = 156) collected from the United States (U.S.), China, Japan, and Korea. Samples were extracted by solid-liquid extraction, purified by automated solid phase extraction methods, and determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The total concentrations of bisphenols (∑BPs; sum of eight bisphenols) in dust were in the range of 0.026-111 μg/g (geometric mean: 2.29 μg/g). BPA, BPS, and BPF were the three major bisphenols, accounting for >98% of the total concentrations. Other bisphenol analogues were rare or not detected, with the exception of BPAF, which was found in 76% of the 41 samples collected in Korea (geometric mean: 0.0039 μg/g). The indoor dust samples from Korea contained the highest concentrations of both individual and total bisphenols. BPA concentrations in dust were compared among three microenvironments (house, office, and laboratory). The estimated median daily intake (EDI) of ∑BPs through dust ingestion in the U.S., China, Japan, and Korea was 12.6, 4.61, 15.8, and 18.6 ng/kg body weight (bw)/day, respectively, for toddlers and 1.72, 0.78, 2.65, and 3.13 ng/kg bw/day, respectively, for adults. This is the first report on the occurrence of bisphenols, other than BPA, in indoor dust.     

Nondestructive decontamination of mortar and concrete by electro-kinetic methods: application to the extraction of radioactive heavy metals

Because the service lives of nuclear power plants are limited to a certain number of years, the need for the management of quite a large volume of radioactive contaminated concrete arises, which, in most cases, was not taken into account when the capacities of the low and medium activity repositories were designed. Therefore, the decontamination of these structures would be of great interest in order to declassify the wastes as radioactive and manage them as conventional ones. This research studies the reliability of the application of electrical fields to decontaminate radioactive contaminated concrete. Three series of decontamination experiments have been carried out, using Cs+, Sr2-, Co2+, and Fe3+ ions added during casting and that have penetrated from the outside, testing carbonated and uncarbonated matrixes, and using laboratory devices as well as the homemade device for in situ application named "honeycomb device". As a result, the application of electrical fields to concrete-contaminated structures has been developed as a new technique to extract radioactive ionic species from concrete. This method of decontamination has been patented by ENRESA (Spanish Company for the Management of Radioactive Wastes) in association with the IETcc.     

Detection of dechlorane plus in residential indoor dust in the city of Ottawa, Canada

Dechlorane plus (DP), a flame retardant recently identified in the air and sediment of the Great Lakes region, has been detected in residential indoor dust in the city of Ottawa, Canada using gas chromatography-mass spectrometry under negative chemical ionization mode. DP was detected in all dust samples with a concentration range of 2.3 to 182 ng g(-1), except for one dust sample (5683 ng g(-1)) which was much higher. The levels of DP in indoor dust were several times higher than those in the sediment of the Great Lakes. The presence of DP in indoor environments could have implications for potential human exposure to this chemical. The daily human intake of DP from dust was estimated using dust ingestion data from the U.S. Environmental Protection Agency. The large variation of the ratio of syn- and anti-DP isomers in the dust samples also suggests a complex degradation process of DP in the environment.     

基于生物可给性的广东省居民主要消费海水鱼膳食暴露评估应用初探

目的 分析广东省居民主要消费海水鱼品种中甲基汞的生物可给性及其影响因素,探讨生物可给性对膳食海水鱼甲基汞暴露的影响.方法 在广州某大型水产贸易市场采集12种海水鱼(共36份样品),经不烹调(生样)、油煎、烘烤或清蒸等4种烹调后,采用体外模型生理原理提取法测定甲基汞生物可给性,比较不同海水鱼、烹调方式之间甲基汞生物可给性...     

Thirdhand smoke: heterogeneous oxidation of nicotine and secondary aerosol formation in the indoor environment

Tobacco smoking is well-known as a significant source of primary indoor air pollutants. However, only recently has thirdhand smoke (THS) been recognized as a contributor to indoor pollution due to the role of indoor surfaces. Here, the effects of relative humidity (<10% RH and ～ 45% RH) and substrate (cellulose, cotton, and paper) on secondary organic aerosol (SOA) formation from nicotine-ozone-NO(x) reactions are discussed. SOA formation from the sorbed nicotine-ozone reaction ([O(3)] = 55 ppb) varied in size distribution and number, depending on RH and substrate type, indicating the role of substrate and water interactions in SOA formation. This led to SOA yields from cellulose sorbed nicotine-ozone reaction of ～ 1 and 2% for wet and dry conditions, respectively. SOA formation from nicotine-NO(x) reactions was not distinguishable from background levels. Simultaneously, cellulose sorbed nicotine-ozone reaction kinetics ([O(3)] = 55 ppb) were obtained and revealed pseudofirst-order surface rate constants of k(1) = (1 ± 0. 5) × 10(-3) and k(1) < 10(-4) min(-1) under <10% and ～ 45% RH, respectively. Given the toxicity of some of the identified products and that small particles may contribute to adverse health effects, the present study indicates that exposure to THS ozonation products may pose additional health risks.     

Column extraction of heavy metals from soils using the biodegradable chelating agent EDDS

A possible remediation strategy for metal polluted soils is washing with chelants. Here, we compare the efficiency of batch and column extraction of Cu, Zn, and Pb from three soils using the biodegradable chelant EDDS. A total of 53-80% of Cu was extracted in batch and 18-26% in column extraction. For Zn, the extractability was 16-50% in batch and 20-64% in columns and for Pb 25-52 and 18-91%, respectively. Column leaching was therefore equally or better suited for Zn and Pb removal. The longer extraction time in the column resulted in more formations of Fe(III)EDDS by slow dissolution of iron oxides. Zn was uniformly washed from the column, while Cu and Pb were extracted in the top layers and deposited in the bottom layers, presumably by biodegradation of the metal-EDDS complexes and slow dissolution of iron oxides. Between 18 and 42% of the applied EDDS was lost through biodegradation after 7 weeks. In short time experiments, only 6% of EDDS was degraded. Using EDDS concentrations in excess of available heavy metals caused pronounced leaching of organic matter and clogging of the column. Our results prove that heap leaching using EDDS is a promising approach to reduce the heavy metal content of polluted soils.     

Estimating tulathromycin withdrawal time in pigs using a physiologically based pharmacokinetics model

A physiologically based pharmacokinetics model was developed to predict tulathromycin concentrations in edible swine tissues. Physiological parameters included volumes of and plasma flows through different tissues which were obtained from the literatures. The tissue/plasma partition coefficient was calculated according to the area method, and the model was validated through a comparison of predicted and observed concentrations. Withdrawal times in different tissues were predicted. The physiologically based pharmacokinetics model presented here provided accurate predictions of the observed concentrations in all tissues. The results showed that the injection site had the longest withdrawal time (21 days), followed by skin together with fat (19 days) and then kidney (10 days), lung (6 days), liver (4 days) and muscle (1 day). A withdrawal time of 21 days was finally predicted for tulathromycin in swine after a single intramuscular injection at 2.5 mg/kg body weight.     

Polybrominated diphenyl ethers in indoor dust in Ottawa, Canada: implications for sources and exposure

Polybrominated diphenyl ethers (PBDEs) are widely used as additive flame retardants in plastics, soft furnishings, electrical and electronic equipment, and insulation in the indoor environment, and may be released indoors via volatilization or as dusts. The penta-and octa-brominated mixes are now banned in most parts of Europe, and phasing out of their use has recently begun in North America. This study follows a previous investigation into indoor air levels of PBDEs. House dust was analyzed from the family vacuum cleaners of 68 of the same 74 randomly selected homes, in Ottawa, Canada during the winter of 2002-2003. PBDEs, comprising on average 42% BDE-209, were found in all samples. The levels were log-normally distributed with a geometric mean sigmaPBDE of 2000 ng g(-1), and a median of 1800 ng g(-1) dust. The levels in dust did not correlate with questionnaire information on house characteristics. Correlations were found between pentamix congener levels in dust and in air from the same homes, but not for congeners of the more highly brominated mixes. Exposure scenarios are presented for mean and high dust ingestion rates, and compared against exposures from other pathways, for both adults and toddlers (6 months-2 years). Assuming a mean dust ingestion rate and median dust and air concentrations, adults would be exposed to ca. 7.5 ng sigmaPBDE d(-1) via the dust ingestion pathway, which represents approximately 14% of total daily exposure when compared to diet (82%) and inhalation (4%). However, for toddlers the equivalent intakes would be 99 ng d(-1), representing 80% of their daily PBDE exposure. At high dust ingestion rates these values increase to 180 ng d(-1) (80% daily intake) for adults and 360 ng d(-1) (89% daily intake) for toddlers. The data give a clearer picture of sources of PBDE exposure in the home environment and suggest that dust could be a significant exposure pathway for some individuals, particularly children.     

Investigation on per- and polyfluorinated compounds in paired samples of house dust and indoor air from Norwegian homes

Per- and polyfluorinated compounds (PFCs) have been found to be ubiquitously distributed in human populations, however the sources of human exposure are not fully characterized. A wide range of PFCs were determined in paired samples of indoor air and dust from 41 Norwegian households. Up to 18 ionic and 9 neutral PFCs were detected. The concentrations found are comparable to or lower than what has previously been reported in North America, Europe, and Asia. The highest median concentrations in dust were observed for perfluorohexanoic acid (28 ng/g), perfluorononanoic acid (23 ng/g), perfluorododecanoic acid (19 ng/g), and perfluorooctanoic acid (18 ng/g). However, perfluoroalkyl sulfonic acids (PFSAs) were also frequently detected. Fluortelomer alcohols were the most prominent compounds found in indoor air, with median concentrations for 8:2 fluortelomer alcohol, 10:2 fluortelomer alcohol, and 6:2 fluortelomer alcohol of 5173, 2822, and 933 pg/m(3) air, respectively. All perfluoroalkyl sulfonamides and sulfonamidoethanols (FOSA/FOSEs) were detected in more than 40% of the air samples. For the first time, significant positive correlations (p < 0.05) between PFSAs in house dust and FOSA/FOSEs in the indoor air have been shown, supporting the hypothesis that FOSA/FOSEs may be transformed to PFSAs. Further, we found the age of the residence to be a predictor of PFC concentrations in both indoor air and house dust. These results are important for estimating the exposure to PFCs from the indoor environment and for characterization of exposure pathways.     

浅谈打包车间粉尘环境的处理

阐述了打包车间粉尘的安全隐患,并对粉尘的控制方法,如除尘器的选择、吸尘罩的安装、排风扇的安装、设备补缺补漏、风管的清理、滤袋的更换以及粉尘的监测展开了分析,以期为打包车间粉尘的治理提供参考。     

Concentrations of polychlorinated biphenyls in indoor air and polybrominated diphenyl ethers in indoor air and dust in Birmingham, United Kingdom: implications for human exposure

Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were measured in air (using PUF disk passive samplers) in 31 homes, 33 offices, 25 cars, and 3 public microenvironments. Average concentrations of sigmaBDE (273 pg m(-3)) and sigmaPCB (8920 pg m(-3)) were an order of magnitude higher than those previously reported for outdoor air. Cars were the most contaminated microenvironment for sigmaBDE (average = 709 pg m(-3)), but the least for sigmaPCB (average = 1391 pg m(-3)). Comparison with data from a previous spatially consistent study, revealed no significant decline in concentrations of sigmaPCB in indoor air since 1997-98. Concentrations in indoor dust from 8 homes were on average 215.2 ng sigmaBDE g(-1), slightly higher than other European dust samples, but twenty times lower than Canadian samples. Inhalation makes an important contribution (between 4.2 and 63% for adults) to overall UK exposure to sigmaPCB. For sigmaBDE, dust ingestion makes a significant but--in contrast to Canada-a not overwhelming contribution (up to 37% for adults, and 69% for toddlers). Comparison of UK and Canadian estimates of absolute exposure to sigmaBDE suggest that differences in dust contamination are the likely cause of higher PBDE body burdens in North Americans compared to Europeans.     

Enzyme-assisted extraction processing from oilseeds: Principle,processing and application

Enzyme-assisted extraction processing (EAEP), feasible alternative to screw pressing and organic solvent extraction technologies, is a promising method for the simultaneous extraction of oil and protein from oilseed. This method incorporates comminuting, extraction buffers and enzymes to allow production of a range of oils and proteins although different challenges appear during the process. The demand for acceptable and high free oil yields and purities of protein is always incompatible in many processes. This review article covers technological aspects of EAEP, and discusses the application of enzymes in pretreatment, extraction and demulsification, and explores the quality characteristics and safety of the oils and proteins obtained, focusing particularly on recent application of EAEP at the laboratory and industrial scale.Industrial relevance

• 1.Enzymes are widely used on an industrial scale but mainly as catalysts, and the applications mainly concerning the synthesis of pharmaceuticals, compounds for chemistry of specialty, polymers, etc.
• 2.At the industrial scale, one advantage of EAEP is environment benefit because it can avoid the risk of organic solvents and particularly hexane.
• 3.The quality of the products produced by the smooth process is usually higher.
• 4.EAEP technique is considered as an alternative method to produce valuable products without loss of quality at moderate conditions.
• 5.Compared with solvent extraction, EAEP is more eco-friendly. Besides that, one of the main advantages of EAEP is the specificity of enzymes.

     

微波萃取技术及其在果胶提取中的应用

微波萃取技术与传统的提取技术相比,具有简便、高效、选择性强、能耗低、环境污染少产品提取率高等优点,因而备受研究人员的关注.文中对微波萃取技术的原理、特点、主要影响因素及其在果胶提取中的应用等进行了综述,并展望了其发展前景.