Continuous Sampling System Research Articles

On-Demand Nanoliter Sampling Probe for the Collection of Brain Fluid.

Continuous fluidic sampling systems allow collection of brain biomarkers in vivo. Here, we propose a new sequential and intermittent sampling paradigm using droplets, called Droplet on Demand (DoD). It is implemented in a microfabricated neural probe and alternates phases of analyte removal from the tissue and phases of equilibration of the concentration in the tissue. It allows sampling droplets loaded with molecules from the brain extracellular fluid punctually, without the long transient equilibration periods typical of continuous methods. It uses an accurately defined fluidic sequence with controlled timings, volumes, and flow rates, and correct operation is verified by the embedded electrodes and a flow sensor. As a proof of concept, we demonstrated the application of this novel approach in vitro and in vivo, to collect glucose in the brain of mice, with a temporal resolution of 1-2 min and without transient regime. Absolute quantification of the glucose level in the samples was performed by direct infusion nanoelectrospray ionization Fourier transform mass spectrometry (nanoESI-FTMS). By adjusting the diffusion time and the perfusion volume of DoD, the fraction of molecules recovered in the samples can be tuned to mirror the tissue concentration at accurate points in time. Moreover, this makes quantification of biomarkers in the brain possible within acute experiments of only 20-120 min. DoD provides a complementary tool to continuous microdialysis and push-pull sampling probes. Thus, the advances allowed by DoD will benefit quantitative molecular studies in the brain, i.e., for molecules involved in volume transmission or for protein aggregates that form in neurodegenerative diseases over long periods.

Continuous vapor sampling of volatile organic compounds associated with explosives using capillary microextraction of volatiles (CMV) coupled to a portable GC–MS

The dynamic sampling and preconcentration device, capillary microextraction of volatiles (CMV), is coupled to a portable GC–MS for the rapid field detection of volatile organic compounds (VOCs) associated with explosives. The results of the portable GC–MS were compared to a benchtop GC–MS throughout this study. Sub-nanogram (ng) instrumental detection limits were achieved for each of the following analytes of interest (3-NT, 2,4-DNT, DPA, EC, DBP and 2-NDPA). Three different dynamic sampling methods were used with the CMV to sample and preconcentrate the volatiles prior to analysis. The headspace of a closed system was sampled over 10 min resulting in recoveries between 0.3 and 12%. Simulated open-air vapor sampling using a previously described vapor source resulted in an improvement of analyte recovery (ranging from 1.6 to 25%), for the same 10-minute sampling. A novel, continuous vapor delivery and sampling system was used, for the first time, to facilitate the delivery of sub-nanogram quantities of explosive analytes. The new continuous delivery system achieved significantly higher recoveries (3.0–89%) for all the analytes while requiring less sampling time (∼5 min) and sampling volumes than the other sampling techniques. The rapid sampling and preconcentration of sub-ng levels of VOCs in field scenarios was coupled to a ∼10-minute portable GC–MS method that compares favorably to the analytical figures of merit achieved by laboratory benchtop instruments and approximates the detection limits reported for canines.

Single dual mode (continuous and cast) instrumentation package for inherent optical property measurements: Characterization of the bucket for backscattering observation

AbstractThis work describes a continuous sampling system that has been designed, implemented, and tested for the acquisition of Inherent Optical Properties (IOPs) during field campaigns. The major challenge of the work was to design and build a flow‐through housing accounting for the complex sensing geometry of the ECO‐VSF3, a backscattering meter, i.e., three sensor heads each of which measures the VSF at three angles. A detailed characterization of the ECO‐VSF3 housing in terms of impact of the boundaries and overall system inertia is reported. A key feature of the system design is the possibility to easily detach the IOP package from the flow‐through hydraulic circuit and use it in cast mode at fixed stations. This, to the best of authors' knowledge, is the first time the ECO‐VSF3 is used in an underway system. Results from the comparison of continuous (Co) and cast (Ca) bb measurements show excellent agreement, with differences not exceeding 7%, thus proving the system to be reliable and highlighting the feasibility for increasing the spatio‐temporal sampling of surface observations.

A Refined Method to Analyze Insoluble Particulate Matter in Ice Cores, and Its Application to Diatom Sampling in the Antarctic Peninsula

The insoluble particulate matter deposited on ice sheets provide key information to reconstruct past climate. The low concentration of some insoluble particulate matter, such as terrigenous particles and microfossils, challenges the efficiency of the recovery and the representativeness of the results. Here we present a new optimized method to extract, quantify and classify targeted low concentration insoluble particulate matter. Particle recovery rates and particle distribution were investigated using polystyrene particle standards filtered through Polycarbonate membrane filters and subsequently scanned in a scanning electron microscope. Experimental results in continuous and discrete sampling systems reveal consistent trends in the transport and removal of particulate material inside a filtration system. Statistical simulations are used to optimize the sample analyses required to achieve representative results. The analysis of diatoms in ice cores using this new method uncovered their potential to hold valuable climate records from the Antarctic Peninsula region. The data presented here evidence the presence of a measurable amount of marine diatoms with sub-annual variations, highlighting the potential of this record as a seasonal indicator. The new method presented provides an optimized and statistically representative approach for extracting, recovering and analyzing micrometre-sized, low-concentration insoluble particulate matter in ice.

Detection of trace metals in biogas using extractive electrospray ionization high-resolution mass spectrometry

On-line measurements of metal emissions in energy conversion systems at very low concentrations are difficult to perform using existing techniques. Metals are of high importance due to their detrimental impact on human health, the environment and various industrial processes and/or equipment. Herewith and for the first time, we report the real-time detection and characterization of metals and trace elements in a Swiss biogas production plant using a novel technology based on an extractive electrospray ionization (EESI) source coupled to a high-resolution time-of-flight mass spectrometer (TOF-MS). The deployment examines the ability of the EESI-TOF to resolve highly transient signals, while providing a relatively straightforward and well-characterized platform for in-field diagnostic measurements. The EESI-TOF-MS was operated in the negative ion production and detection mode, and qualitative and quantitative results for a range of trace metals (e.g. Fe, Cu, Zn, Cd, Pb, etc.) were obtained. On-site results showed fast responses (1 Hz) and detection limits below 3 ng/m3. In addition, the EESI-TOF-MS was used for the off-line analysis of condensable trace metals of biogas samples collected using a continuous liquid-quench sampling system in 2-propanol. The results of the offline and online methods were compared and show good agreement.

Efficacy of the novel continuous sampling system for PCDD/Fs and unintentional persistent organic pollutants.

Long-term sampling is essential for monitoring the air pollutants emitted from stack since it can monitor the pollutants emission continuously including the stages of start-up, shutdown and normal operation. However, commercial continuous sampling equipment such as AMESA faces the challenges of high weight and complicated sampling procedures. This study has developed a long-term and automatic sampling system (National Central University continuous stack sampling system, NCU-CS3), and compared the efficiency with manual sampling train (MST). The results indicate that relative standard deviation (RSD) of PCDD/Fs concentrations measured between NCU-CS3 and MST is <20%, demonstrating that the difference between NCU-CS3 and MST in measuring PCDD/Fs is insignificant. Besides, the effects of adsorbent temperature, adsorbent amount and type of adsorbent on breakthroughs of PAHs and unintentional-persistent organic pollutants (UPOPs) such as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), chlorinated phenols (CPs), chlorinated benzenes (CBs) and polychlorinated naphthalenes (PCNs) are evaluated. The results indicate that the breakthrough of pollutants increases with increasing temperature of XAD-2 and decreases with increasing XAD-2 amount. Moreover, XAD-4 is used as alternative adsorbent to test the breakthrough and the results indicate that the breakthroughs of UPOPs of XAD-4 as adsorbent are lower than that with XAD-2 due to higher specific surface area of XAD-4. Furthermore, the residual of PCDD/Fs with NCU-CS3 as the sampling train is relatively low (1.5-3.8%), which meets the regulation of EN 1948-5 (10%).

The impact of sea ice on the air-sea exchange of mercury in the Arctic Ocean

Atmospheric deposition is the main input of mercury (Hg) to the ocean, even in remote locations such as the Arctic. Furthermore, evasion of elemental Hg (Hg°) is the major sink for oceanic Hg. As a result, air-sea exchange is an important part of the oceanic Hg cycle. To examine the air-sea exchange of Hg in the Arctic Ocean we made high resolution measurements of Hg° in surface waters and Hg speciation in the atmosphere using continuous sampling systems during the 2015 U.S. Arctic GEOTRACES cruise from August 9 to October 12. Additionally, samples were obtained for measurement of total Hg and methylmercury (CH3Hg) in wet deposition and bulk aerosols as well as surface snow and sea ice. We used these measurements made in the water and the atmosphere to estimate fluxes of Hg° from the ocean to the atmosphere. Concentrations of dissolved Hg° (Hg°diss) were near saturation in ice-free waters (32 ± 30 fM) and resultant fluxes were low; however, Hg° was highly enriched under contiguous ice (101 ± 98 fM, up to 544 fM) suggesting the continual formation of Hg° in waters even when ice covered. Predicted evasion fluxes in these regions (these being potential rates for locations under ice) were as high as 492 pmol m−2 h−1. Atmospheric Hg° concentrations averaged 1.2 ± 0.1 ng m−3 with little variation over the course of the cruise even above waters with elevated Hg°diss, indicating that sea ice acts as a barrier to air-sea exchange. Measurements of Hg in precipitation and aerosols were lower than have been found in more coastal regions of the Arctic. We used these concentrations to estimate deposition of Hg and CH3Hg during the time of the cruise. Overall, wet deposition represented 88% of the CH3Hg flux and 38% of the HgT flux. Our flux estimates confirm the importance of air-sea exchange in Hg cycling in the Arctic and suggest that evasion was greater than deposition, indicating a net loss of Hg from the Arctic during this period or the presence of other sources not measured during this study. Additionally, our results suggest that fluxes for offshore waters are lower than found in coastal regions of the Arctic. From these estimates, we predict how Hg concentrations may respond to future changes in ice cover and other potential impacts of climate change on Hg dynamics and food web bioaccumulation in this important ocean region.

Air contamination measurements for the evaluation of internal dose to workers in nuclear medicine departments

Radionuclides handled in nuclear medicine departments are often characterized by high volatility and short half-life. It is generally difficult to monitor directly the intake of these short-lived radionuclides in hospital staff: this makes measuring air contamination of utmost interest. The aim of the present work is to provide a method for the evaluation of internal doses to workers in nuclear medicine, by means of an air activity sampling detector, to ensure that the limits prescribed by the relevant legislation are respected. A continuous air sampling system measures isotope concentration with a Nal(TI) detector. Energy efficiency of the system was assessed with GEANT4 and with known activities of 18F. Air is sampled in a number of areas of the nuclear medicine department of the IRST-IRCCS hospital (Meldola- Italy). To evaluate committed doses to hospital staff involved (doctors, technicians, nurses) different exposure situations (rooms, times, radionuclides etc) were considered. After estimating the intake, the committed effective dose has been evaluated, for the different radionuclides, using the dose coefficients mandated by the Italian legislation. Error propagation for the estimated intake and personal dose has been evaluated, starting from measurement statistics.

Assessment of volatile organic compounds and particulate matter in a dental clinic and health risks to clinic personnel

This study was conducted to assess (1) levels of volatile organic compounds (VOCs) and particulate matter (PM) in a dental clinic in southern Taiwan and (2) dental care personnel's health risks associated with due to chronic exposure to VOCs. An automatic, continuous sampling system and a multi-gas monitor were employed to quantify the air pollutants, along with environmental comfort factors, including temperature, CO2, and relative humidity at six sampling sites in the clinic over eight days. Specific VOC compounds were identified and their concentrations were quantified. Both non-carcinogenic and carcinogenic VOC compounds were assessed based on the US Environmental Protection Agency's Principles of Health Risk Assessment in terms of whether those indoor air pollutants increased health risks for the full-time dental care professionals at the clinic. Increased levels of VOCs were recorded during business hours and exceeded limits recommended by the Taiwan Environmental Protection Agency. A total of 68 VOC compounds were identified in the study area. Methylene methacrylate (2.8 ppm) and acetone (0.176 ppm) were the only two non-carcinogenic compounds that posed increased risks for human health, yielding hazard indexes of 16.4 and 4.1, respectively. None of the carcinogenic compounds increased cancer risk. All detected PM10 levels ranged from 20 to 150 μg/m3, which met the Taiwan EPA and international limits. The average PM10 level during business hours was significantly higher than that during non-business hours (P = 0.04). Improved ventilation capacity in the air conditioning system was recommended to reduce VOCs and PM levels.

Dispersive liquid–liquid microextraction and microsample injection system coupled with inductively coupled plasma-mass spectrometry for inorganic arsenic speciation in natural waters

A method was developed for inorganic arsenic speciation analysis of water samples by a microsample injection system coupled with inductively coupled plasma mass spectrometry (MIS-ICP-MS) following a validated dispersive liquid–liquid microextraction (DLLME). Prior to DLLME speciation analysis, a simple robust microsample injection system was successfully adapted to ICP-MS. A sampling volume of 90 µL provided almost the same signals as the signals obtained by means of a conventional continuous nebulization sampling system for the ICP-MS instrument. After DLLME, the final solution was injected into nebulizer of ICP-MS using the microsample injection system. Under the optimized conditions, the analyte from only 5.0 mL water sample was concentrated by a factor of 48 with detection limits reaching 0.0031 µg L−1 for arsenic. The calibration curve had a linear range of 0.0084–0.0800 µg L−1 (r 2 = 0.999). The relative standard deviations (RSD, n = 6) were <4%. The proposed method was applied to the speciation of inorganic arsenic in various water samples with satisfactory results. The determination of arsenite and total As in river, pond, tap and bottled water samples was acheived by the standard addition method. The recoveries for spiked As(III) and As(V) from understudied water samples were in the range of 95–108%.

Characterizing Microbial Community and Geochemical Dynamics at Hydrothermal Vents Using Osmotically Driven Continuous Fluid Samplers

Microbes play a key role in mediating aquatic biogeochemical cycles. However, our understanding of the relationships between microbial phylogenetic/physiological diversity and habitat physicochemical characteristics is restrained by our limited capacity to concurrently collect microbial and geochemical samples at appropriate spatial and temporal scales. Accordingly, we have developed a low-cost, continuous fluid sampling system (the Biological OsmoSampling System, or BOSS) to address this limitation. The BOSS does not use electricity, can be deployed in harsh/remote environments, and collects/preserves samples with daily resolution for >1 year. Here, we present data on the efficacy of DNA and protein preservation during a 1.5 year laboratory study as well as the results of two field deployments at deep-sea hydrothermal vents, wherein we examined changes in microbial diversity, protein expression, and geochemistry over time. Our data reveal marked changes in microbial composition co-occurring with changes in hydrothermal fluid composition as well as the temporal dynamics of an enigmatic sulfide-oxidizing symbiont in its free-living state. We also present the first data on in situ protein preservation and expression dynamics highlighting the BOSS's potential utility in meta-proteomic studies. These data illustrate the value of using BOSS to study relationships among microbial and geochemical phenomena and environmental conditions.

Dois planos de amostragem para análise de fumonisinas em milho

O objetivo deste trabalho foi avaliar a eficiência de dois planos de amostragem para análise de fumonisinas (B1+B2) em 11 lotes de milho. Empregaram-se o plano de amostragem manual em grãos inteiros, através do calador graneleiro e o plano de Amostragem Automático em Fluxo Contínuo em grãos moídos (AAFC). Para a comparação dos dois planos de amostragem, foram utilizadas duas medidas de dispersão: a variância e o coeficiente de variação. Em cada plano de amostragem, foram determinadas as variâncias associadas às três etapas do procedimento de detecção das fumonisinas (amostragem, preparação da amostra e análise) e os coeficientes de variação total. A correlação entre as médias de concentrações de fumonisinas e as variâncias de cada etapa do procedimento de detecção foi avaliada para cada plano amostral através da análise de regressão. Na AAFC de milho moído para análise de fumonisinas, obtiveram-se resultados inferiores (P&lt;0,01) de variância na etapa de amostragem (0,0226mg kg-1)², assim como no coeficiente de variação total (6,37%), quando comparados com a variância da amostragem manual (0,0685mg kg-1)² e coeficiente de variação total do plano de amostragem manual em grãos inteiros (8,94%), apresentando, portanto, maior eficiência na detecção de fumonisinas em milho.

High resolution monitoring system for IRE stack releases

The main activity of IRE (Institute for Radio-Element) is radioisotope production of bulk 99Mo and 131I for medical application (diagnosis and therapy). Those isotopes are chemically extracted from HEU (High Enriched Uranium) targets activated in reactors. During this process, fission products are released from the targets, including noble gases isotopes (Xe and Kr). Like any nuclear plant, IRE has release limits which are given by the Belgium authority and moreover IRE is in the process of continuously reducing the level of its releases. To achieve this mission, the need of an accurate tool is necessary and IRE has developed a specific monitoring system using a high resolution detector in order to identify and accurately estimate its gaseous releases. This system has a continuous air sampling system in the plant main stack. The sampled gases cross charcoal cartridges where they are slowed down and concentrated for higher detection efficiency. In front of those cartridges is installed an HPGe detector with a detection chain connected to a specific analysis system allowing on-line spectrum analysis. Each isotope can be separately followed without interferences, especially during the production process where high activity can be released. Due to its conception, the system also allows to measure iodine isotopes by integration on the charcoal cartridges. This device is of great help for accurately estimate IRE releases and to help for understanding specific releases and their origin in the production or maintenance process.

Management of atmospheric pollutants from waste incineration processes: the case of Bozen

This article presents the case study of a waste incinerator located in a region rich in natural and environmental resources, and close to the city of Bozen, where there are about 100,000 inhabitants. Local authorities paid special attention to the effect of the plant on human health and the surrounding environment. Indeed, among the measures adopted to control the emissions, in 2003 an automatic sampling system was installed specifically to monitor polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran (PCDD/F) emissions during the complete operation time of the plant. The continuous sampling system was coupled directly to aerosol spectrometers for the determination of fine and ultra-fine particles in the emissions of the plant. The measurement results suggest that the waste incineration plant of Bozen is not a significant source of PCDD/F, or fine and ultra-fine particles. Immission measurements from other monitoring systems confirmed these results.

Liquid-Quench Sampling System for the Analysis of Gas Streams from Biomass Gasification Processes. Part 1: Sampling Noncondensable Compounds

In biomass gasification plants and related research units, on-line analysis of noncondensable compounds (H-2, CO, CO2, CH4, and light hydrocarbons) and condensable compounds (water, tars, etc.) is desired. Long-duration on-line measurements are often a challenging task, because blocking of the sampling lines has to be avoided and because some analytical equipment do not tolerate certain components of these streams. A continuous liquid-quench sampling system has been successfully employed to sample these gas streams and prepare them for on-line measurement. In comparison to other systems, it promotes long-duration measurements with high time resolution over a wide concentration range with little man-hour requirements. In this work, the sampling system is described in detail for the first time and its performance is investigated regarding the sampling of noncondensable compounds. On the basis of experimental observations, optimal operational parameters are suggested to minimize the measurement bias.

Volatile Properties of Particles Emitted by Compressed Natural Gas and Diesel Buses during Steady-State and Transient Driving Modes

Volatile properties of particle emissions from four compressed natural gas (CNG) and four diesel buses were investigated under steady-state and transient driving modes on a chassis dynamometer. The exhaust was diluted utilizing a full-flow continuous volume sampling system and passed through a thermodenuder at controlled temperature. Particle number concentration and size distribution were measured with a condensation particle counter and a scanning mobility particle sizer, respectively. We show that while almost all the particles emitted by the CNG buses were in the nanoparticle size range, at least 85% and 98% were removed at 100 and 250 °C, respectively. Closer analysis of the volatility of particles emitted during transient cycles showed that volatilization began at around 40 °C, with the majority occurring by 80 °C. Particles produced during hard acceleration from rest exhibited lower volatility than those produced during other times of the cycle. On the basis of our results and the observation of ash deposits on the walls of the tailpipes, we suggest that these nonvolatile particles were composed mostly of ash from lubricating oil. Heating the diesel bus emissions to 100 °C removed ultrafine particle numbers by 69-82% when a nucleation mode was present and just 18% when it was not.

Limnoperna fortunei (Dunker 1857) en el Sistema de Embalses del Rio Negro, Uruguay

Normal 0 21 false false false PT-BR X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabela normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi; mso-fareast-language:EN-US;} LIMNOPERNA FORTUNEI (DUNKER 1857) IN THE RESERVOIR NEGRO RIVER SYSTEM, URUGUAY. Limnoperna fortunei is an invasive mollusk species reported in the Plata Basin since 1991, invading the major water systems in the region, affecting human infrastructure and causing ecological alterations. In Uruguay it is reported in five of the six major river basins, including the system of reservoirs in Río Negro since 1999. The development of population control strategies to mitigate the effects caused by this species requires basic studies of their life cycle. This contribution describes the annual cycle of pelagic stages and larval settlement of L. fortunei in the reservoir Palmar, Río Negro. Sampling was conducted during 2006-2008, using continuous sampling systems, static or stratified ones, by seasonal or monthly intervals. Environmental parameters were similar to previous studies in the system, the zooplankton community showed holo (Rotifera, Crustacea) and merozooplankton ( L. fortunei larvae), showing a seasonal behavior. The golden mussel larvae showed a seasonal pattern with peaks during austral spring and autumn and absence during winter, and did not differ between strata analyzed and the various stages did not show a clear temporal variation. The temperature did not show significant associations with larval abundances but was a set of environmental variables (temperature, Kd and residence time) which explained the variability of the zooplankton community and larvae of L. fortunei. The abundance L. fortunei individuals settled showed spatial and temporal variations, the minimum was found in February and March and the maximum in December. Significant differences were found between the abundance of organisms settled on substrates located at surface (0.5m) and bottom (10m). The observed maximum size of an individual settled was 22mm body large, showing differences in growth between surface and bottom. Recruitment patterns showed two peaks per year: January-February and September-October, coinciding with pelagic annual cycle, as evidenced by two annual cohorts, results similar to other studies in the region. The identification of larval behavior and settlement patterns of the golden mussel in the reservoir Palmar make possible the design of control strategies for the Río Negro reservoirs. Keywords: golden mussel; zooplankton; larvae; reservoir; Uruguay.

Transmission of Alkali Aerosols through Sampling Systems

AbstractIn biomass gasification, particles such as condensed alkali salts pose a threat on equipment. Due to high loads of condensable tars in the gases, sampling of these particles to liquids and subsequent analysis of the liquid is frequently the method of choice for measuring the alkali concentration in the gas. However, little is known about the collection efficiency of liquid sampling devices. By measuring the aerosol transmission using a surface ionization detector, two continuous sampling systems are compared with conventional impinger bottles. A low collection efficiency for the latter was found, but down to nearly zero transmission for the continuous sampling systems. The main mechanisms for mass transfer from gas to liquid are discussed with emphasis on particle removal in gas slugs in two‐phase flow inside tubes of the sampling system.

Assessing the trends and effects of environmental parameters on the behaviour of mercury in the lower atmosphere over cropped land over four seasons

Abstract. Mercury is released to the atmosphere from natural and anthropogenic sources. Due to its persistence in the atmosphere, mercury is subject to long range transport and is thus a pollutant of global concern. Mercury emitted to the atmosphere enters terrestrial and aquatic ecosystems which act as sinks but also as sources of previously emitted and deposited mercury when the accumulated mercury is emitted back to the atmosphere. Studying the factors and processes that influence the behaviour of mercury from terrestrial sources is thus important for a better understanding of the role of natural ecosystems in the mercury cycling and emission budget. A study was conducted over ten months (November 2006 to August 2007) at Elora, Ontario, Canada to measure gaseous elemental mercury (GEM), reactive gaseous mercury (RGM) and particulate bound mercury (HgP) as well as GEM fluxes over different ground cover spanning the four seasons typical of a temperate climate zone. GEM concentrations were measured using a mercury vapour analyzer (Tekran 2537A) while RGM and HgP were measured with the Tekran 1130/1135 speciation unit coupled to another mercury vapour analyzer. A micrometeorological approach was used for GEM flux determination using a continuous two-level sampling system for GEM concentration gradient measurement above the soil surface and crop canopy. The turbulent transfer coefficients were derived from meteorological parameters measured on site. A net GEM volatilization (6.31 ± 33.98 ng mM−2 hr−1, study average) to the atmosphere was observed. Average GEM concentrations and GEM fluxes showed significant seasonal differences and distinct diurnal patterns while no trends were observed for HgP or RGM. Highest GEM concentrations, recorded in late spring and fall, were due to meteorological changes such as increases in net radiation and air temperature in spring and lower atmospheric mixing height in fall. Highest GEM fluxes (18.1 ng m−2 hr−1, monthly average) were recorded in late spring but also during specific events in winter and fall. The main factors influencing the GEM flux were soil moisture content, soil temperature, precipitation events and ground cover. These trends indicate that the soil surface could be a significant mercury source in spring and summer seasons but also under specific meteorological conditions during the winter and fall.

Air contamination analysis during emergency medical treatment

After radiological emergencies, patients contaminated with radioactivity are taken to radiation emergency hospitals for treatment. Numerical simulations using the computer software 'Flow Designer((R))' were made in order to evaluate indoor air contamination caused by the breathing out of contaminated air. The National Institute of Radiological Sciences facility was used for the numerical evaluation. Results indicate that the dispersion of contaminated air depends on the characteristics of the contaminants, and that the dispersion range was limited and localised. Only medical staff standing in a special position near the patient was exposed to almost un-diluted contaminated air. Highly contaminated air was evacuated with a local exhaust pump system. Room air quality was monitored using a continuous air sampling system, but it was found that the sampling point was not representative for the purpose of radiation protection. From the air-flow analysis, some problems that affect radiological safety were revealed and valuable information and measures for preventing secondary contamination were determined.