Air formaldehyde and solvent concentrations during surface coating with acid-curing lacquers and paints in the woodworking and furniture industry

An investigation of contemporary exposure to formaldehyde and organic solvents has been carried out during surface coating with acid-curing lacquers and paints in the Norwegian woodworking and furniture industry over a period of 3 years. The investigation covered 27 factories of different sizes and with different types of production, and totally 557 parallel formaldehyde and solvent samples were collected. The formaldehyde concentration (geometric mean) was 0.15 ppm (range 0.01-1.48 ppm) with about 10% of the samples exceeding the Norwegian occupational exposure limit of 0.5 ppm. The solvent concentration as additive effect (geometric mean) was 0.13 (range 0.0004-5.08) and about 5% of the samples exceeded the Norwegian occupational exposure limit. The most frequently occurring solvents from acid-curing lacquers were n-butyl acetate, ethanol, ethyl acetate and 1-butanol, which were found in 88-98% of the samples. Toluene, n-butyl acetate and 1-butanol were the only solvents with maximum concentrations exceeding their respective occupational exposure limits. Curtain painting machine operators were exposed to the highest concentrations of both formaldehyde (geometric mean 0.51 ppm, range 0.08-1.48 ppm) and organic solvents (additive effect, geometric mean 1.18, range 0.02-5.08). Other painting application work tasks such as automatic and manual spray-painting, manual painting and dip painting, showed on average considerably lower concentrations of both formaldehyde (geometric means 0.07-0.16 ppm) and organic solvents (additive effect, geometric mean 0.02-0.18). Non-painting work tasks also displayed moderate concentrations of formaldehyde (geometric means 0.11-0.17 ppm) and organic solvents (additive effect, geometric mean 0.04-0.07).     

液液萃取-气质联用法测定饮用水源地水中SVOCs

采用乙酸乙酯-正己烷混合溶剂（体积比为2∶1）对饮用水源地水中阿特拉津、林丹、邻苯二甲酸二正丁酯（DBP）、邻苯二甲酸二（2-乙基己基）酯（DEHP）和滴滴涕（含4种）等8种半挥发性有机物进行1次水样萃取,用气质联用法同时测定。试验表明,方法在25．0μg/L～500μg/L范围内线性良好;检出限在0．006μg/L ～0．028μg/L 之间;空白水样3个质量浓度水平的加标回收率为87．6％～109％,平行测定6次的 RSD＜5．1％;测定集中式生活饮用水源地的实际水样,未检出目标化合物,加标回收率为98．6％～109％。     

气相色谱法测定空气中丙烯酸酯

讨论了用气相色谱仪测定被污染空气中丙烯酸甲酯、丙烯酸乙酯、甲基丙烯酸甲酯、丙烯酸丁酯的方法条件。方法检出下限在６ｎｇ范围,相对标准偏差为１４～６９％,回收率为９０６～１１０５％。实验还显示丙烯酸酯污染空气问题不容忽视。     

Airborne chemical compounds on dairy farms

The chemical environment that dairy farmers are exposed to during milking was investigated. Volatile organic compounds (VOCs) were analysed and identified, and the levels of formaldehyde, ammonia and carbon dioxide were measured in eight farms in northern Sweden. Both stationary and personal samples were taken. A total of 70 VOCs were identified from the adsorbent samples, with p-cresol, 2-butanone, ethyl acetate, alpha-pinene and delta 3-carene occurring at the highest levels. All monitored levels were significantly lower for compounds having a stated highest occupational exposure level (OEL). Using multivariate techniques some differences in the composition of the workplace air between and within the farms were found. No difference was found between personal exposure and the surrounding environment in the cowshed.     

SPE-GCMS法分析饮用水源水中痕量半挥发性有机物

采用C 18固相萃取柱富集,乙酸乙酯、二氯甲烷和丙酮混合溶剂以1∶1∶1比例洗脱、自动固相萃取的前处理方法,气相色谱质谱连用,分析水源水中33种半挥发性有机物,并与液液萃取前处理方法进行比较。结果表明:在500~5 000μg/L范围内,33种SVOC线性良好,相关系数0.990,回收率为70.1%~114.2%,相对标准偏差为2.4%~13.4%,方法检出限为0.06~0.25μg/L;而且该方法较液液萃取,检出样品种类多。适用于饮用水源水中半挥发性有机物的监测。     

Organophosphates in aircraft cabin and cockpit air--method development and measurements of contaminants

Methods for measurements and the potential for occupational exposure to organophosphates (OPs) originating from turbine and hydraulic oils among flying personnel in the aviation industry are described. Different sampling methods were applied, including active within-day methods for OPs and VOCs, newly developed passive long-term sample methods (deposition of OPs to wipe surface areas and to activated charcoal cloths), and measurements of OPs in high-efficiency particulate air (HEPA) recirculation filters (n = 6). In total, 95 and 72 within-day OP and VOC samples, respectively, have been collected during 47 flights in six different models of turbine jet engine, propeller and helicopter aircrafts (n = 40). In general, the OP air levels from the within-day samples were low. The most relevant OP in this regard originating from turbine and engine oils, tricresyl phosphate (TCP), was detected in only 4% of the samples (min-max 相似文献   

Reproducibility and imputation of air toxics data

Ambient air quality datasets include missing data, values below method detection limits and outliers, and the precision and accuracy of the measurements themselves are often unknown. At the same time, many analyses require continuous data sequences and assume that measurements are error-free. While a variety of data imputation and cleaning techniques are available, the evaluation of such techniques remains limited. This study evaluates the performance of these techniques for ambient air toxics measurements, a particularly challenging application, and includes the analysis of intra- and inter-laboratory precision. The analysis uses an unusually complete-dataset, consisting of daily measurements of over 70 species of carbonyls and volatile organic compounds (VOCs) collected over a one year period in Dearborn, Michigan, including 122 pairs of replicates. Analysis was restricted to compounds found above detection limits in > or =20% of the samples. Outliers were detected using the Gumbell extreme value distribution. Error models for inter- and intra-laboratory reproducibility were derived from replicate samples. Imputation variables were selected using a generalized additive model, and the performance of two techniques, multiple imputation and optimal linear estimation, was evaluated for three missingness patterns. Many species were rarely detected or had very poor reproducibility. Error models developed for seven carbonyls showed median intra- and inter-laboratory errors of 22% and 25%, respectively. Better reproducibility was seen for the 16 VOCs meeting detection and reproducibility criteria. Imputation performance depended on the compound and missingness pattern. Data missing at random could be adequately imputed, but imputations for row-wise deletions, the most common type of missingness pattern encountered, were not informative. The analysis shows that air toxics data require significant efforts to identify and mitigate errors, outliers and missing observations, and that these steps are essential and should be performed prior to using these data in receptor, exposure, health and other applications.     

沉积物中多氯联苯分析的纯化条件优化研究

比较了各种填料层析柱和洗脱液的差别,并根据有机溶剂使用量较少的样品纯化方案,建立了适用低有机质含量水体表层沉积物中不同极性多氯联苯(PCBs)的分析方法.结果表明,该方法检测限在0.11 ng/g～0.35 ng/g(干重)之间,对主要多氯联苯同族体的回收率是77.9%～112.1%.用该法分析了长江中下游水体表层沉积物中的PCBs,质控结果表明,该纯化方法的效果理想.     

Effect of sampling method on contaminant measurement in pore-water and surface water at two uranium operations: can method affect conclusions?

This paper describes a comparison of two methods of sediment pore-water sampling and two methods of surface water sampling that were used in a broader investigation of cause(s) of adverse effects on benthic invertebrate communities at two Saskatchewan uranium operations (Key Lake and Rabbit Lake). Variables measured and compared included pH, ammonia, DOC, and trace metals. The two types of sediment pore-water samples that were compared are centrifuged and 0.45-microm filtered sediment core samples vs. 0.2-microm dialysis (peeper) samples. The two types of surface water samples that were compared are 53-microm filtered Van Dorn horizontal beta samples vs. 0.2-microm dialysis (peeper) samples. Results showed that 62% of the sediment core pore water values were higher than the corresponding peeper pore-water measurements, and that 63% of the Van Dorn surface water measurements were lower than corresponding peeper surface water measurements. Furthermore, only 24% and 14% of surface water and pore-water measurements, respectively, fell within +/-10% range of one another; 73% and 50%, respectively, fell within +/-50%. Although somewhat confounded by differences in filtering method, the observed differences are believed to primarily be related to small, vertical differences in the environment sampled. Despite observed differences in concentrations of toxicologically relevant variables generated by the different sampling methods, the weight of evidence (WOE) conclusions drawn from each set of exposure data on the possible cause(s) of in situ toxicity to Hyalella azteca from a related study were the same at each uranium operation. However, this concurrence was largely due to other dominant lines of evidence. The WOE conclusions at Key Lake were dominated by the toxicity response of H. azteca in relation to exposure chemistry, where as the WOE conclusions at Rabbit Lake were informed by exposure chemistry, the toxicological response of H. azteca, and whole-body contaminant concentrations in the test organisms. Had these multiple lines of evidence not been available, differences in exposure chemistry generated by the different sampling methods could have substantially influenced the identification of potential causes of in situ toxicity.     

加速溶剂萃取-凝胶净化色谱-气相色谱质谱法测定农用地土壤中有机氯农药方法研究

通过对加速溶剂萃取、平行蒸发及净化方法等环节的优化实验,建立了加速溶剂萃取-凝胶净化色谱-气相色谱质谱法测定农用地土壤中23种有机氯农药的检测方法。结果表明,方法检出限为0.0034~0.0052 mg/kg;对化合物质量分数为0.25 mg/kg的土壤加标样品进行平行实验,回收率为82.0%~93.7%;测定结果的相对标准偏差（RSD）≤8.7%。对土壤有证标准质控样品进行分析,测定结果均在验收范围之内。该方法准确可靠,灵敏度较高,样品净化效果较好,能够满足农用地土壤中有机氯农药残留痕量分析的要求。     

气相色谱-电子捕获法直接测定水体中的五氯酚钠

建立了不经衍生直接测定水体中五氯酚钠残留量的气相色谱-电子捕获(GC-ECD)方法。用乙酸乙酯提取目标化合物,浓缩后上机测定。五氯酚钠标准溶液的线性范围在0.35～400μg/L之间,相关系数为0.9992;池塘水中五氯酚钠的添加浓度为1.0、5.0、10.0μg/L时,其加标回收率为95.8%～98.7%,相对标准偏差≤3.6%;检出限(信噪比为3时)为0.35μg/L,定量限(信噪比为10时)为1.0μg/L。     

Determination of solvents permeating through chemical protective clothing with a microsensor array

The performance of a novel prototype instrument in determining solvents and solvent mixtures permeating through samples of chemical protective clothing (CPC) materials was evaluated. The instrument contains a mini-preconcentrator and an array of three polymer-coated surface-acoustic-wave (SAW) microsensors whose collective response patterns are used to discriminate among multiple permeants. Permeation tests were performed with a 2.54 cm diameter test cell in an open-loop configuration on samples of common glove materials challenged with four individual solvents, three binary mixtures, and two ternary mixtures. Breakthrough times, defined as the times required for the permeation rate to reach a value of 1 microg cm(-2) min(-1), determined by the instrument were within 3 min of those determined in parallel by manual sampling and gas chromatographic analysis. Permeating solvents were recognized (identified) from their response patterns in 59 out of 64 measurements (92%) and their vapor concentrations were quantified to an accuracy of +/- 31% (typically +/- 10%). These results demonstrate the potential for such instrumentation to provide semi-automated field or bench-top screening of CPC permeation resistance.     

气相色谱分析中样品介质不同对分析结果的影响

分析了用甲醇、乙酸乙酯和二硫化碳3种不同极性的介质配制的4种苯系物样品,在不同极性的石英毛细柱、不同的分流比、宽口径石英毛细柱、宽口径玻璃毛细柱和玻璃填充柱上的测量结果。指出不同介质的有机化合物样品在气相色谱上分析时,色谱柱的极性(非极性、中等极性、强极性)、色谱柱类型(毛细柱、宽口径毛细柱、填充柱)、分流比的大小、进样方式(分流、不分流)都对数据的一致性产生影响,但采用不分流方式的宽口径毛细柱或填充柱分析可使分析结果具有一致性或更准确。     

加速溶剂萃取-固相萃取小柱净化-气相色谱法测定土壤中有机磷农药

建立了加速溶剂萃取-固相萃取小柱净化-气相色谱法测定土壤中12种有机磷农药的方法。推荐了12种有机磷农药快速分离的色谱条件。采用加速溶剂萃取技术实现了对土壤中有机磷农药残留的提取,选取最佳条件参数,减少了组分的损失,提取回收率达88%～108%。选择不同填料的SPE小柱和洗脱溶剂形成3种方案法进行净化实验,结果表明,方案2采用混合溶剂(正己烷、丙酮、二氯甲烷体积比为1∶1∶1)洗脱上样后的硅胶SPE小柱的净化效果好,回收率为91%～121%。方法检出限为0.000 1～0.000 2 mg/kg,石英砂基体和实际污染土壤样品加标回收率为62%～112%,相对标准偏差为0.7%～8.6%。该方法操作简便,快捷,灵敏度高,检出限低,试剂用量少,准确度和精密度符合质量控制要求。     

Ozone facilitated dechlorination of 2-chloroethanol and impact of organic solvents and activated charcoal

The ozone-initiated oxidation of 2-chloroethanol was followed by monitoring the consumption of the halogenated organic substrate. Gas chromatographic analysis of the ozonated products showed an increase in conversion from about 1 % after 3 h of ozone treatment to about 22 % after 12 h. The yields of major ozonated products identified and quantified namely acetaldehyde, acetic acid, and chloride ion increased proportionately as a function of ozone treatment time. The percent conversion of 2-chloroethanol in the presence of acetic acid or ethyl acetate were found to be higher than those under solvent-free conditions with similar products obtained. The use of activated charcoal during the ozonolyis of 2-chloroethanol showed a significant increase in the percent conversion of the substrate compared to solvent free ozonation. Based on the experimental findings, the overall mechanism for the reaction between 2-chloroethanol and ozone is described.     

The evaluation of a low resolution fourier transform infrared (FTIR) gas analyser for monitoring of solvent emission rates under field conditions

The applicability of a low resolution (8 cm-1) Fourier transform infrared (FTIR) gas analyser with an absorption path length of 3 m was evaluated for the on-line monitoring of organic solvent mixture emissions in a flexographic ink manufacturing plant. The on-line monitoring revealed that the highest variations of solvent concentrations, up to three decades, occurred in the exhaust air. The FTIR analyser with a dynamic range of four decades covers well the concentration ranges typically found in the exhaust air and in the workroom air of ink manufacturing plants. The average emission rate of solvent mixture based on a sampling period of two days was 1.8 kg h-1 consisting of mainly ethanol (70%), ethyl acetate (15%) and propan-2-ol (11%). The detection limits of the analyser for the solvent compounds ranged from 0.3 to 4.3 mg m-3 and the measurement uncertainty was less than 10% in the concentration range of 8-15,000 mg m-3. These characteristics make the apparatus appropriate for most industrial hygiene applications. An FTIR spectrophotometer, equipped with an multipoint sampling unit, facilitates rapid identification of solvent components, real-time display of concentration data relevant to workroom air and environment monitoring as well as process control. Furthermore, the on-line concentration information enabled a rapid selection of representative sampling locations. The spectrophotometer is transportable, rugged and relatively simple to calibrate even in a hostile industrial environment.     

底质农残测定中固相柱净化体系的选择

使用固相柱对底质中的7种农残进行净化。结果表明,在相同淋洗条件下,使用氟罗里硅土柱比硅胶柱净化效果好。比较了不同溶剂体系、不同溶剂配比下2种萃取柱的净化效果,选择乙醚-正己烷(体积比1∶2)或丙酮-正己烷(体积比1∶4)作为净化溶剂,较小的收集体积都可满足所有目标化合物的回收率要求;相比较而言,丙酮-正己烷(体积比1∶4)作为净化溶剂,洗脱液的杂质干扰更小,净化效果更好。使用氟罗里硅土柱和丙酮-正己烷(体积比1∶4)对样品净化,方法简单,快速,净化效果好,适合大批量底质样品的前处理净化过程。     

Evaluation of method of preparation of passive diffusion tubes for measurement of ambient nitrogen dioxide

This study was carried out in response to suggestions that the measurement of NO(2) by Palmes-type passive diffusion tubes (PDT) is affected by the method of preparation of the triethanolamine (TEA) absorbent coating on the grids. The following combinations of factors were investigated: TEA solvent (acetone or water), volume composition of TEA in solvent (50% or 20%), and grid coating method (dipping in solution prior to assembly or pipetting solution on after assembly). Duplicate PDTs prepared by each of the 8 methods were exposed in parallel, in urban air, for a total of 80 separate 1 week exposures. NO(2) concentrations derived from PDTs prepared by pipetting methods were significantly less precise than concentrations from dipping methods, with mean RSDs for duplicate measurements of 13.8% and 8.5%, respectively (n= 316 each category). Pipetting methods using solutions of 50% TEA composition were particularly imprecise (mean RSD 17.2%). Data from PDTs prepared by pipetting methods were systematically more poorly correlated with each other and with data from co-located chemiluminescence analysers, than corresponding data from PDTs prepared by dipping methods, indicating that more consistent accuracy was also obtained by the latter PDTs. The statistical evidence suggested that PDTs prepared by pipetting 50% TEA in water generally gave lower NO(2) concentrations. Although this is in agreement with a previous study, it is also possible that such an observation here may be a statistical artefact given the demonstrably poorer precision of this method. The general tendency of PDTs to show positive bias in NO(2) measurement in urban air in 1 week exposures was again evident in this study (mean biases at roadside and urban centre locations of +35% (n= 475) and +18% (n= 112), respectively) consistent with augmentation of within-tube NO(2) flux by chemical reaction between co-diffusing NO and O(3). Overall, it is recommended that the pipetting method of PDT grid preparation is avoided, or at least investigated further, because of the apparent degradation in precision and accuracy of NO(2) measurement. Potential reasons for the effect are discussed.     

Measurement of styrene-7,8-oxide and other oxidation products of styrene in air

Styrene-7,8-oxide (SO) is generated at low concentrations from the oxidation of styrene during the processing of reinforced plastics. Since exposure to SO has important health implications, we developed air sampling and analytical methods to measure low levels of airborne SO in the presence of styrene and its other oxidation products, namely phenylacetaldehyde (PAA) and acetophenone (AP). Both active and passive air monitors were used. The active sampling method, which employed adsorption on Tenax, was suitable for measuring SO, PAA and AP but had limited capacity for styrene due to breakthrough. The passive monitor employed a carbon adsorbent and was suitable for measurement of styrene and SO but not PAA and AP due to poor recovery. After sampling, the analytes were extracted from the adsorbents with ethyl acetate and measured by gas chromatography with flame ionization detection or mass spectrometry. By maintaining the injection port at 70 degrees C, the thermal rearrangement of SO to PAA was minimized. Recovery of styrene and SO from the passive monitor depended upon loading and was corrected by linearization of the Freundlich isotherm. The limits of detection for SO, PAA, and AP were 0.2 ppb using the active monitor, and for SO was 1 ppb using the passive monitor. The sampling precision for SO (RSD from personal measurements) was 5.0% for the passive monitor and was 13.4% for the active monitor over a range of exposures from 5-150 ppb. The corresponding precision for styrene was 5.3% for the passive monitor for levels ranging from 1.2 to 104 ppm. Measurements of 235 personal exposures with the active monitor in 12 facilities manufacturing fiberglass-reinforced plastics (FRP) showed that levels of AP and PAA were below 7.8 ppb and 5 ppb, respectively. In contrast, SO averaged 30.4 ppb (SE=2.4) in these FRP facilities, ranging from below 0.2 ppb to 190 ppb. The active monitor was also used to detect airborne SO at levels of approximately equals 1 ppb in one facility manufacturing styrene butadiene rubber, suggesting that SO is generally present during the polymerization of styrene. Personal passive monitoring in the 12 FRP facilities (n = 657) revealed mean concentrations of styrene ranging between 1.8 and 55.4 ppm, and for SO between 1.7 and 62.6 ppb. The ratio of the mean styrene level to the mean SO level varied between 449:1 and 1,635:1 among the 12 FRP facilities.     

Comparison of pressurized fluid extraction, Soxhlet extraction and sonication for the determination of polycyclic aromatic hydrocarbons in urban air and diesel exhaust particulate matter

In order to characterize and compare the chemical composition of diesel particulate matter and ambient air samples collected on filters, different extraction procedures were tested and their extraction efficiencies and recoveries determined. This study is an evaluation of extraction methods using the standard 16 EPA PAHs with HPLC fluorescence analysis. Including LC analysis also GC and MS methods for the determination of PAHs can be used. Soxhlet extraction was compared with ultrasonic agitation and pressurized fluid extraction (PFE) using three solvents to extract PAHs from diesel exhaust and urban air particulates. The selected PAH compounds of soluble organic fractions were analyzed by HPLC with a multiple wavelength shift fluorescence detector. The EPA standard mixture of 16 PAH compounds was used as a standard to identify and quantify diesel exhaust-derived PAHs. The most effective extraction method of those tested was pressurized fluid extraction using dichloromethane as a solvent.