Evaluation of the measurement uncertainty in automated long-term sampling of PCDD/PCDFs.

Since the publication of the first version of European standard EN-1948 in 1996, long-term sampling equipment has been improved to a high standard for the sampling and analysis of polychlorodibenzo-p-dioxin (PCDD)/polychlorodibenzofuran (PCDF) emissions from industrial sources. The current automated PCDD/PCDF sampling systems enable to extend the measurement time from 6-8 h to 15-30 days in order to have data values better representative of the real pollutant emission of the plant in the long period. EN-1948:2006 is still the European technical reference standard for the determination of PCDD/PCDF from stationary source emissions. In this paper, a methodology to estimate the measurement uncertainty of long-term automated sampling is presented. The methodology has been tested on a set of high concentration sampling data resulting from a specific experience; it is proposed with the intent that it is to be applied on further similar studies and generalized. A comparison between short-term sampling data resulting from manual and automated parallel measurements has been considered also in order to verify the feasibility and usefulness of automated systems and to establish correlations between results of the two methods to use a manual method for calibration of automatic long-term one. The uncertainty components of the manual method are analyzed, following the requirements of EN-1948-3:2006, allowing to have a preliminary evaluation of the corresponding uncertainty components of the automated system. Then, a comparison between experimental data coming from parallel sampling campaigns carried out in short- and long-term sampling periods is realized. Long-term sampling is more reliable to monitor PCDD/PCDF emissions than occasional short-term sampling. Automated sampling systems can assure very useful emission data both in short and long sampling periods. Despite this, due to the different application of the long-term sampling systems, the automated results could not be directly compared with manual results, not even in terms of measurement uncertainty. This investigation focuses on both uncertainty and repeatability of the automated sampling method. The standard 20988, developed by Internarional Organization of Standardization (ISO) can be used to estimate the measurement uncertainty. The results confirm that the uncertainties of manual and automated methods are comparable. At the same time, it is not appropriate to consider the manual method as a reference for the evaluation of the uncertainty of the automated sampling system, due to the high variability of both systems.

Long-term automated sampling of PCDD/PCDF flue gas: current status and critical issues.

After entry into force of the Stockholm Convention and Aarhus Protocol and in order to implement the upcoming European legal background, the European countries are asked to apply control measures to reduce the release of persistent organic pollutants (POPs) such as dioxins and furans (PCDD/PCDF) and polychlorinated biphenyls as well as to establish POPs release inventories. In this perspective, development of measuring techniques of emissions is a focal issue in acquiring useful information. In this paper, results of various measurement campaigns at different municipal waste incineration (MWI) plants using long-term automated sampling of PCDD/PCDF are presented. The samples collected from both manual and automated campaigns were analyzed following the European Standard EN-1948:2006 by high-resolution gas chromatograph/high-resolution mass spectrometer. Performances of two different commercial systems have been investigated. Anomalous values occurred during one long-term campaign (22.16 pg I-toxic equivalent (TEQ)/Nm(3)), compared to average values (4-5 pg I-TEQ/Nm(3)) of the MWI. At this maximum value, a main occurrence of abnormal and instable operating conditions has been found. Sampling based on long-term basis was found to be more reliable to monitor PCDD/PCDF emissions than occasional short-term sampling. Nevertheless, the results of long-term campaigns demonstrate that emission levels detected in 15-30 days campaigns, when unsteady operating conditions can occur, as start-up and shut down, are not immediately comparable to the typical levels in a 6-8 h, when operating conditions are generally stable. Moreover, there are often differences observed in the congener profiles between short- and long-term campaigns.

Concentration of organic micropollutants in the atmosphere of Trieste, Italy.

PURPOSE: PCDD/Fs, PCBs, and PAHs, ubiquitous environmental pollutants which are part of the POPs, are mainly produced by anthropogenic activities as well as by natural processes. Occurrences of these pollutants in different sites in Trieste are presented. PCDD/Fs distribution and their possible emission sources are discussed. METHODS: Air samples were collected in different sites near the industrial area, in the city center, and in a background area, using a high-volume sampler equipped with a quartz fiber filter and a PUF. Each sampling lasted a week. RESULTS: The concentrations of the organochlorinated pollutants are consistent with literature data (ΣPCDD/Fs and Σdl-PCBs were 5-38 fg TEQ/Nm(3) and 4-31 fg TEQ/Nm(3), respectively), and an apparent seasonal trend was found with slightly higher concentrations in the winter and lower levels in both summer campaigns. Moreover, the isomer profile of each sampling campaign was compared to the fingerprint of a sintering plant, a cement plant, and an incinerator, the main industrial activities in Trieste. CONCLUSIONS: The organic micropollutants were detected in levels consistent with literature data. The results show that the pollutants are uniformally distributed in the atmosphere of Trieste. PCDD/F fingerprints in each site remained almost identical during summer and winter, confirming the yearly prevalence of the emissions from the nearby sintering plant.

Characterisation and evaluation of the emissions from the combustion of Orimulsion-400, coal and heavy fuel oil in a thermoelectric power plant.

An experimental campaign was carried out in a thermoelectric power plant in Southern Italy in order to evaluate the emissions released during the utilisation of three different fuels, Orimulsion-400, coal and heavy fuel oil (HFO) with high content of sulphur. Macropollutant concentrations in the exhaust gases were recorded by the continuous monitoring system and the Institute on Atmospheric Pollution of the Italian National Research Council (CNR) carried out samplings and analysis of Polycyclic Aromatic Hydrocarbons (PAHs), Polychlorodibenzo-p-dioxins (PCDD) and Polychlorodibenzofurans (PCDF), halogenidric acids and metals. The pollutant concentrations, mass flows and emission factors were compared. Each fuel met the air emission limits for all the pollutants. Coal showed the highest emission levels, whilst HFO and Orimulsion were fairly similar. NOx, SO2 and particulate matter showed constant concentration for all the fuels, while Orimulsion and HFO SO2 concentrations were critical at the highest operating power. Orimulsion showed the lowest PAHs values and PCDDs and PCDFs were much lower than the limits, for all the fuels. Particular attention must be paid with vanadium and nickel during Orimulsion utilisation. For these metals mass balances were carried out.

High-performance liquid chromatographic analysis of norfloxacin in human tissues and plasma with fluorescence detection.

A high-performance liquid chromatographic analysis with fluorimetric detection is described for the quantitative determination of norfloxacin in renal, prostatic tissues and in plasma. The analytical procedure in the tissue pretreatment, consists of purification of the obtained sample by a solid state extraction and quantitation by HPLC. The samples were chromatographed on a C(8) reversed-phase column. Analytical recoveries ranged from 95.2 to 97.6%. Within and between day precision were assessed by analysing serum containing 50 and 500 ng/ml norfloxacin. At each concentration, within day precision was < or = 3.6% (relative standard deviation, n = 10) and day-to-day precision was < or = 5.3% (n = 10). Limit of detection was ca 1 ng/ml.

High-performance liquid chromatographic determination of norfloxacin in human tissues and plasma with fluorescence detection.

A high-performance liquid chromatographic method with fluorimetric detection is described for the quantitative determination of norfloxacin in renal and prostatic tissues and in plasma. It consists of tissue pretreatment, purification by solid-state extraction and separation and quantification by high-performance liquid chromatography on a C8 reversed-phase column. Analytical recoveries ranged from 95.2 to 97.6%. Within-day and between-day precision were assessed by analysing serum containing 50 and 500 ng/ml norfloxacin. At each concentration, the within-day precision was less than or equal to 3.6% (coefficient of variation; n = 10) and the day-to-day precision was less than or equal to 5.3% (n = 10). The limit of detection was 1 ng/ml.

HPLC determination of benzydamine and its metabolite N-oxide in plasma following oral administration or topical application in man, using fluorimetric detection.

A method for the extraction and quantification of benzydamine and its metabolite N-oxide by liquid chromatography with fluorescence detection in plasma samples is described. This method has adequate sensitivity, specificity and is reproducible. The use of the extraction column allowed a recovery of both benzydamine and its metabolite of over 97% to be obtained. The plasma levels of benzydamine and its metabolite N-oxide were studied after oral administration as sugar-coated tablets or topical application to the vaginal mucosa as a cream to 6 healthy volunteers. After topical application, the plasma concentrations of the unchanged drug and its metabolite are lower than those obtained following oral administration. These data further stress the concept that, whenever possible, topical use should be considered the treatment of choice since, along with a more selective therapy, the incidence of systemic side effects can be considerably reduced.

Sample-pretreatment procedure for routine liquid chromatographic assay of serum cortisol.

A specific method for measuring concentrations of cortisol in serum, by preliminary isolation on a "minicolumn" followed by elution and determination by liquid chromatography, is described. This assay requires only 500 microl of serum. The limit of determination of cortisol was found to be 5 microg l . The analytical recovery of cortisol added to serum ranged from 98 to 102%. The coefficients of variation ranged from 2.4 to 3.4% (within-day) and from 3.6 to 8.8% (day-to-day), depending on the cortisol concentration. The method compares well with a commonly used radioimmunological method.