A comparative study of (239,240)Pu in soil near the former Rocky Flats Nuclear Weapons Facility, Golden, CO

The Rocky Flats Nuclear Weapons Plant near Golden, CO released plutonium into the environment during almost 40 years of operation. Continuing concern over possible health impacts of these releases has been heightened by lack of public disclosure of the US Department of Energy (DOE) activities. A dose reconstruction study for the Rocky Flats facilities, begun in 1990, provided a unique opportunity for concerned citizens to design and implement field studies without participation of the DOE, its contractors, or other government agencies. The Citizens Environmental Sampling Committee was formed in late 1992 and conducted a field sampling program in 1994. Over 60 soil samples, including both surface and core samples, were collected from 28 locations where past human activities would have minimal influence on contaminant distributions in soil. Cesium-137 activity was used as a means to assess whether samples were collected in undisturbed locations. The distribution of plutonium (as (239,240)Pu) in soil was consistent with past sampling conducted by DOE, the Colorado Department of Public Health and Environment, and others. Elevated levels of (239,240)Pu were found immediately east of the Rocky Flats Plant, with concentrations falling rapidly with distance from the plant to levels consistent with background from fallout. Samples collected in areas south, west, and north of the plant were generally consistent with background from fallout. No biases in past sampling due to choice of sampling locations or sampling methodology were evident. The study shows that local citizens, when provided sufficient resources, can design and implement technical studies that directly address community concerns where trust in the regulated community and/or regulators is low.     

The study of Central Taiwan particles concentration variations during earthquake period

Ambient particle concentration was taken on the traffic sampling site over the Chung-Chi Road over the bridge (CCROB) in front of Hungkuang Institute of Technology (HKIT). The sampling time was from August 1999 to December 1999. During the sampling period, Taiwan's biggest earthquake in more than a century registered 7.3 on the Richter scale (Taiwan Chi-Chi Earthquake). Besides, there are more than 20,000 aftershocks following the Taiwan Chi-Chi Earthquake within 3 months. Thus, the mass concentration of particles with aerodynamic diameters smaller than 2.5 microm (PM2.5) and PM2.5-10 was also collected then compared with the total mass concentration of suspended particles (TSP) in this study. The average TSP, PM2.5-10, and PM2.5 concentrations are 106, 24.6, and 58.0 microg/m3, respectively, after the Taiwan Chi-Chi Earthquake. The average TSP concentrations before and after Taiwan Chi-Chi Earthquake were 69.6 and 127 microg/ m3, respectively. In addition, statistical analysis of the PM10 data from this study and EPA in 1999 yielded a Tstatistic of 0.147, which is smaller than t(0.975,18) = 2.101. It is indicated that there was no significant difference. So, the PM10 concentrations measured after Taiwan Chi-Chi Earthquake in this study were also greater than those data previously obtained from Taiwan EPA in the same region of this area. The relationships between TSP, PM10, PM2.5-10, and PM2.5 particle concentrations and wind speed (R2) are .77, .59, .58, .58, respectively. And the ratios of PM2.5/PM25-10, PM2.5/PM10, and PM10/TSP are 221%, 67.2%, 58.0%, respectively. The average ratios of PM2.5/PM2.5-10 and PM2.5/PM10 increase by about 120% and 17%. It indicated that the fine-particles concentration increases compared to the coarse-particles concentration after 921 Taiwan Chi-Chi Earthquake. And the proposed reasons are that local motor vehicle emissions combined the fine particles transported from the Chi-Chi epicenter. More importantly, the wind direction was mainly blown from southeastern part. These two main factors enhance the fine-particles concentration in this area.     

Development of a personal exposure monitor for two sizes of inhalable particulates

Measurement of personal exposure to ambient level particulate concentrations is often extremely difficult because of a lack of personal exposure monitors capable of collecting measurable quantities within a meaningful sampling period. A new personal exposure monitor for two fractions of inhalable particulates (i.e., the 3–15 μm aerodynamic diameter and the < 3 μm or respirable fraction) has been developed and characterized. This monitor is capable of collecting a sample of each fraction that is quantifiable with ambient concentrations of inhalable/respirable particulates as low as 25 μg/m³ in a 24-h sampling period. Wind tunnel tests have been made on the particulate personal exposure monitor to determine sampling efficiency as a function of relative wind speed and orientation with respect to the sampler.     

Inverse dependency of particle residence times in ponds to the concentration of phosphate, the limiting nutrient

234Th, a commonly used short-lived particle-reactive tracer in marine systems, was measured in three different holding pond series at the Rocky Flats Environmental Technology Site (RFETS), Colorado, along with its parent nuclide 238U, to determine steady-state residence times of particle-reactive actinides such as Pu, and of particles. Series B ponds, which received industrial effluent that includes ortho-phosphate (PO4) and actinides, differed from series A and C ponds, which did not. This difference was also evident in the calculated particle residence times, which were <1 day for the ponds B4 and B5, where PO4 concentrations were higher (1.4 and 1.8 mg/l), and 3 and 3.4 days for ponds A3 and C2, respectively, where ortho-phosphate concentrations were lower (<0.1 mg/l). Particle residence times thus showed an inverse relationship with the concentration of ortho-phosphate, the limiting nutrient in fresh water systems. The same relationship to the concentration of ortho-phosphate or any of the other nutrient elements was not evident for the residence times of dissolved 234Th, which ranged between 0.1 and 2 days. This can be attributed to higher concentrations of dissolved and particulate ligands with greater binding potential for actinides such as four-valent Th and Pu in ponds with higher ortho-phosphate concentrations. Regardless of actual ortho-phosphate concentration, however, at water residence (holding) times of 1 month in these ponds, particles and associated actinides would be expected to be completely removed from the pond water to sediments.     

Preparation and characterization of diesel exhaust particles for biological experiments

Bioassays of diesel engine exhaust components are being conducted at IITRI to determine toxic and carcinogenic potentials of the exhaust. The bioassay method, intracheal instillation of saline suspensions of test materials in hamsters, requires preparation of stable suspensions of test materials. A method to prepare suspensions of whole particle diesel exhaust in saline has been developed. The diesel exhaust particle material was supplied to IITRI as a dry, loose powder by the U.S. EPA from a light duty diesel test engine. Preliminary characterizations of the powders indicated aggregation of exhaust particles had occurred both before and during capture on collection substrates. Flake-like sheets and hollow spheres of aggregated particles up to 150 μm in sie present in the powders. Therefore, the powder were ball-milled to geometric particle sizes more amenable to the animal administration technique to be employed. Grinding, suspension preparation and particle concentration assaying methods have been developed. Particle (geometric) size and morphological characterizations have also been performed on the as-received powders and prepared suspensions. A method to prepare emulsions (liquid-liquid suspensions) of the dichloromethane extracts of whole particle diesel exhaust has also been developed.     

Volumetric assessment of airborne fungi in two sections of a rural indoor dairy cattle shed

There is increasing concern about the exposure to fungal aerosols in occupational environments and associated respiratory allergic diseases and asthma. A large number of people work in cattle sheds around the world, pulmonary function impairments and higher frequency of respiratory symptoms have been reported in dairy farmers; however, it appears that adequate information on the fungal aerosols from the cattle sheds are largely lacking. Volumetric assessment of airborne culturable and nonculturable fungal spores was performed in two sections of a large rural indoor cattle shed of West Bengal, India for 2 consecutive years. An Andersen Two Stage Viable Sampler was used for sampling culturable fungi and a Burkard Personal Slide Sampler was used to collect the total airborne fungal spores including both the culturable and nonculturable types. A total of 31 spore types and 35 types of viable colony-forming units were recorded. Average concentration range of total fungal spores was 233-2985/m(3) and concentration of viable colony-forming units ranged between 165 and 2225 CFU/m(3). Burkard Sampler showed higher frequencies of Aspergilli/Penicilli, Cladosporium, Alternaria, and smut spores. Andersen Sampler showed the prevalence of Aspergillus niger, Aspergillus flavus and Cladosporium cladosporioides colonies. Some recorded fungi were earlier reported as allergenic, toxic, and pathogenic for occupational workers as well as cattle population. Higher concentration levels of airborne total and culturable fungal spores were recorded during the months of November through February (winter) and June through September (late summer and rainy season).     

An intercomparison of results from samplers used in the determination of aerosol composition

An EPA sponsored field study intercompared the performance of 11 different aerosol samplers. They were operated simultaneously for eight consecutive days by scientific groups having expertise in sampler development and operation. Collection surfaces were changed every 12 h allowing a 16 period intercomparison. Samples were analyzed at each participant's laboratory for one or more of the pollutants mass, nitrate, sulfur or sulfate, lead, and 8 other elements using one or more analysis methods. Most samplers collected two particle-size fractions with the 50% separation for the fine fraction between 2.4 and 4.3 μm. Upper cutoff diameters ranged from 14 to above 30 μm which strongly influenced the total mass collected. Results were intercompared for the total, fine, and coarse size fractions. Agreement to better than 10% was found for the elements Zn, S, and Pb that occur primarily in the fine fraction. Mean sulfate concentration was three times the sulfur concentration, showing that all sulfur occurs as sulfate.     

Vertical migration of 134Cs bearing soil particles in arid soils: implications for plutonium redistribution

Vertical migration of plutonium in soils at the Waste Isolation Pilot Plant (WIPP) and the Rocky Flats Environmental Technology Site (RFETS) was evaluated based on observed 134Cs migration in soil column experiments. After applying 134Cs-labeled soil particles to the surfaces of large, undisturbed soil cores collected from each site, resulting soil columns were subjected to experimental cycles of irrigation plus drying (treatment columns) or to cycles of irrigation only (control columns). Mean losses of 134Cs inventory from soil surfaces were 3.1 +/- 0.6% cycle(-1) and 0.7 +/- 0.6% cycle(-1) respectively for RFETS treatment and control columns. WIPP columns had mean respective losses of 1.3 +/- 1.2% cycle(-1) and 0.5 +/- 0.2% cycle(-1). Bulk transport of labeled soil particles through soil cracks was an important process in RFETS soils, accounting for 64-86% of total 134Cs migration. Colloidal transport processes governed migration in WIPP soils.     

Crystallisation kinetics of mullite glass-ceramics obtained from alumina–silica wastes

Mullite-based glass-ceramics were produced from aluminium hydroxide sludge resulting from the anodisation process and waste glasses. Phase development for crystallisation of amorphous mullite was investigated between 900°C and 1200°C. The kinetic parameters such as activation energy of crystallisation and Avrami exponent for the samples were evaluated from differential thermal analysis curves using various heating rates (5–30°C) and particle size ranges ( < 45, 80–125 and 355–400 μm). The growth morphology parameters ‘n’ and ‘m’ are in the range of 2.5–5.4 and 1.5–4.4, respectively, indicating that bulk nucleation is dominant in mullite crystallisation followed by two- to three-dimensional growth of mullite crystals controlled by diffusion from a varying number of nuclei.     

Mineralogical,chemical and toxicological characterization of urban air particles

Systematic characterization of morphological, mineralogical, chemical and toxicological properties of various size fractions of the atmospheric particulate matter was a main focus of this study together with an assessment of the human health risks they pose. Even though near-ground atmospheric aerosols have been a subject of intensive research in recent years, data integrating chemical composition of particles and health risks are still scarce and the particle size aspect has not been properly addressed yet. Filling this gap, however, is necessary for reliable risk assessment. A high volume ambient air sampler equipped with a multi-stage cascade impactor was used for size specific particle collection, and all 6 fractions were a subject of detailed characterization of chemical (PAHs) and mineralogical composition of the particles, their mass size distribution and genotoxic potential of organic extracts. Finally, the risk level for inhalation exposure associated to the carcinogenic character of the studied PAHs has been assessed. The finest fraction (< 0.45 μm) exhibited the highest mass, highest active surface, highest amount of associated PAHs and also highest direct and indirect genotoxic potentials in our model air sample. Risk assessment of inhalation scenario indicates the significant cancer risk values in PM 1.5 size fraction. This presented new approach proved to be a useful tool for human health risk assessment in the areas with significant levels of air dust concentration.     

Airborne 131I at a background monitoring site

As part of an environmental surveillance program, measurements of 131I in samples of atmospheric aerosols were determined in week-long collection periods at 0.3 km and 1.5 km from a municipal-sewage sludge incinerator located in Albany, New York. During an 11-month period when the sampler was temporarily located near the incinerator, sampling canisters of activated charcoal nearly always contained detectable airborne 131I activity (range of 0.1-6.0 mBq m(-3)). In contrast, remote concentrations where the sample was normally located were near or below analytical detection limits, both before and after the 11-month relocation. Activities of wet and dry fallout at both locations were below detection limits. The source of 131I in the aerosols associated with the sewage sludge was likely excreta from patients following medical treatments at local hospitals.     

Seasonal assessment of environmental tobacco smoke and respirable suspended particle exposures for nonsmokers in Bremen using personal monitoring

The study was designed to determine seasonal differences in personal exposures to respirable suspended particles (RSP) and environmental tobacco smoke (ETS) for nonsmokers in Bremen, Germany. The subjects were office workers, either living and working in smoking locations or living and working in nonsmoking locations. One hundred and twenty four randomly selected nonsmoking subjects collected air samples close to their breathing zone by wearing personal monitors for 24 h or, in some cases, for 7-day periods during the winter of 1999. The investigation was repeated in the summer with 126 subjects, comprised of as many of the studied winter population (89 subjects) as possible. Saliva cotinine analyses were undertaken to verify the nonsmoking status of the subjects. Subjects wore one personal monitor while at work and one while away from the workplace on weekdays, and a third monitor at the weekend. Collected air samples were analysed for RSP, nicotine, 3-ethenylpyridine (3-EP) and ETS particles. The latter were estimated using ultraviolet absorbance (UVPM), fluorescence (FPM) and solanesol (SolPM) measurements. ETS exposure was consistently higher in the winter than in the summer, this pattern being particularly evident for subjects both living and working with smokers. The highest median 24-h time weighted average (TWA) concentrations of ETS particles (SolPM, 25 microg m(-3)) and nicotine (1.3 microg m(-3)) were recorded for subjects performing weekday monitoring during the winter. These were significantly higher than equivalent levels of ETS particles (SolPM, 2.4 microg m(-3)) and nicotine (0.26 microg m(-3)) determined during the summer. There were no appreciable differences between winter and summer percent workplace contributions to median TWA ETS particle and nicotine weekday concentrations, the workplace in Bremen, in general, contributing between 35% and 61% of reported median concentrations. Workers, on average, spent one-third of their time at work during a weekday, indicating that concentrations were either comparable or higher in the workplace than in the home and other locations outside the workplace. Median 24-h weekend ETS particle and nicotine concentrations for smoking locations were not significantly different from equivalent weekday levels during the winter, but were significantly lower during the summer. Based upon median 24-h TWA SolPM and nicotine concentrations for the winter, extrapolated to 1 year's ETS exposure, those subjects both living and working in smoking locations (the most highly exposed group) would potentially inhale 13 cigarette equivalents/year (CEs/y). However, based on a similar extrapolation of summer measurements, the same group of subjects would potentially inhale between 1.3 and 1.9 CEs/y. The most highly exposed subjects in this study, based upon 90th percentile concentrations for those both living and working in smoking locations during the winter, would potentially inhale up to 67 CEs/y in the winter and up to 22 CEs/y in the summer. This clearly demonstrates that seasonal effects should be taken into account in the design and interpretation of ETS exposure studies. Air sampling over a 7-day period was shown to be technically feasible, and subsequent RSP, ETS particle and nicotine levels determined by 7-day monitoring were not found to be significantly different from equivalent levels determined by 24-h monitoring. However, the longer sampling period resulted in the collection of an increased quantity of analytes, which improved the limits of quantitation (LOQ) and allowed a more accurate determination of low level ETS exposure. This was reflected by a reduced percentage of data falling below the LOQ for 7-day monitoring compared with 24-h monitoring. The use of a liquid chromatographic method with tandem mass spectrometric detection for saliva cotinine measurement afforded a greatly improved LOQ and greater accuracy at low concentrations compared with the radioimmunoassay (RIA) method used in previous studies by these authors. In this study, 17 subjects out of 180 tested (9.4%) were found to have saliva cotinine levels exceeding the selected threshold of 25 ng ml(-1) used to discriminate between smokers and nonsmokers.     

Deposition velocities for full-scale corn and soybean canopies: A wind tunnel simulation

Deposition velocities have been determined for corn and soybeans in the first 4–6 weeks of growth in a full-scale study of canopy flow in a wind tunnel. Particles of 1, 5, 10 and 15 μm aerodynamic diameter made of sodium florescein were injected into the Environmental Wind Tunnel Facility at Colorado State University. Deposition velocities were determined as a function of free stream velocity (183, 305 and 610 cm/s) and approach flow turbulence intensity (～1% and 8%). Plants were arranged in realistic field configurations. Hot-wire anemometer studies confirmed that the fluid velocity profiles developed in the wind tunnel were similar to the flow realized in canopies in natural fields. An increase in velocity and turbulence intensity was found to decrease the deposition velocities. A minimum deposition velocity was observed at a particle diameter of 5 μm.     

Processes for sustainable development using high-intensity electric fields

Intense electric fields up to 10⁷ V/m generate very interesting and useful applications for the environment. Several processes using high electrical voltage for environment preservation were developed in the laboratory. The purpose of this study was to review these applications, highlighting their economic and environmental benefits: (1) electrostatic separators of particles used in industrial wastes recycling; (a) role-type electrostatic separator for granular mixtures of plastic–metal particles; (b) free-fall and rotating belt triboelectric separators for mixtures of plastic–plastic particles; (c) plate-type electrostatic separator for mixtures of metal–metal particles, (2) electrostatic precipitators for gas cleaning and (3) ozone generators for air and water treatment.     

Time pattern of off-site plutonium deposition from rocky flats plant by lake sediment analyses

A sediment core from a lake downwind of the Rocky Flats Plant, where nuclear weapons components are produced, was used to reconstruct a time pattern of off-site plutonium deposition. Core sections were dated by analyses of ¹³⁷Cs, ^239,240Pu, ²³⁸Pu, and ²⁴¹Am fallout from nuclear testing and ²³⁸Pu fallout from a satellite failure. A peak in transuranic concentrations occurred in late 1969 which was attributable to the Plant. This was confirmed by mass isotopic analysis of plutonium isotopes in selected core segments where the global fallout and Plant contributions could be differentiated. The 18 nCi ^239,240Pu per m² from the Plant that had accumulated in the sediment is reasonable when compared to soil analyses.     

Spatiotemporal characteristics of wildfire frequency and relative area burned in larch-dominated forests of Central Siberia

Wildfire frequency, relative area burned, and fire return intervals (FRI) have been studied in larchdominated forests along the transect from the southern (45° N) to the northern (73° N) distribution limits of larch stands based on analysis of satellite imagery (NOAA/AVHRR, Terra/MODIS; 1996–2015) and collection of tree cross cuts with fire scars. A significant increasing trend in fire extent (R² = 0.50, p &lt; 0.05) has been revealed. Histograms of fire extent and frequency are bimodal in the southern and middle taiga (with peaks in spring–summer and late summer–autumn periods) but become unimodal toward the north (&gt;55° N). The length of FRI increases from 80 years at 62° N to ~200 years at the Arctic Circle and reaches ~300 years near the northern limit of larch stands, showing a significant inverse correlation with the length of fire season (r =–0.69). In turn, the length of fire season, area burned and FRI are closely correlated with latitudinal variation in solar irradiance (r = 0.97, 0.81, and –0.95, respectively).     

Separate waste collection in Italy: the role of socio-cultural factors and targets set by law

The aim of this paper was twofold: on the one hand, we analyse the results achieved in terms of percentages of separate collection in Italy by testing the effectiveness of Legislative Decree 152/2006 in improving the separate collection process; and on the other hand, we investigate on some of the factors, related to the sociocultural local context, that could explain the different impacts of the law in the three macro-areas considered (North, Central and South Italy). To this purpose, an econometric analysis on the Italian regions for the 1996–2013 period is performed, comparing the period before (1996–2006) and after (2006–2013) the date of entry into force of the new law. The results show the effectiveness of Legislative Decree 152/2006 in promoting separate collection, although a regional difference in terms of separate collection rate is observed. Northern regions proved to be more dynamic and reactive to the above-mentioned legislation, while Central and especially Southern regions achieved poorer results in moving to higher separate waste collection rates. Finally, our work provides evidence on some local factors that may have hampered an effective policy implementation in Southern regions, among them, the presence of criminal activities and the lack of citizen participation in politics.     

The performance of solar powered desiccant dehumidifier in India: an experimental investigation

The regeneration and adsorption of desiccant wheel for producing the dry air was experimentally investigated. The air needed for regeneration was heated in an evacuated tube solar collector with surface area 4.44 m². The desiccant wheel is regenerated at the temperature in the range of 43.9–72.6°C. The regeneration and adsorption performances are affected by the regeneration temperature, wheel rotation, air flow rate (process and regeneration) and ambient conditions. By comparing the adsorption and regeneration performance at different air flow rate and constant rph, it was found that maximum adsorption and regeneration rates are obtained at air flow rate of 210.789 kg/h. Regeneration temperature directly affects the effectiveness of the desiccant wheel. Maximum desiccant wheel effectiveness of regeneration sector and adsorption sector is obtained at air flow rate of 105.394 kg/h. The regeneration performance of desiccant wheel with evacuated tube solar air collector is suitable for the Indian climate.     

Decabromodiphenyl ether (deca-BDE) commercial mixture components, and other PBDEs, in airborne particles at a UK site

The occurrence of the major components of the decabromodiphenyl ether (deca-BDE) flame retardant and other PBDEs was investigated in daily air particulate samples from 17th April to 20th May 2004 at a semi-rural site in north-west England. BDE-209 was found at between <0.49 and 100 pg m(-3) (median 13 pg m(-3)), and other higher-brominated PBDE congeners were also found, particularly the nona-BDEs (e.g. BDE-207: <0.042-79 pg m(-3), median 2.5 pg m(-3)). Deca- and nona-BDEs dominated the median particulate sample congener profile: 60% BDE-209, 16% BDE-207, 6% BDE-208 and 4% BDE-206. Nona-BDEs were greatly enriched, relative to BDE-209, compared to the deca-BDE commercial mixture, which may suggest degradation of BDE-209 between source and sampling site, or release from older deca-BDE commercial mixtures, which may have contained higher proportions of nona-BDEs. The highest PBDE concentrations occurred when air-masses passed over urban and industrial areas to the SSW-SW, though small local influences may also be seen. PBDE concentrations appear to have been influenced mainly by particle levels: 1-3 microm diameter particles for BDE-153, and 3-10 microm particles for BDEs with 7-10 Br atoms. BDE-153 may either be released from combustion sources, or re-condense onto small particles after emission, whereas BDE-209 and nona-BDEs appear to be associated with larger dust particles from industrial or domestic sources.     

Particulate collection in a high temperature cyclone

A new particle collection technique is analyzed and presented for its potential application in a high temperature, high pressure gas cleaning system. The technique is based on the collision and the aglomeration phenomena among the coal-ash particles when the cyclone is operated near the coal-ash fusion temperature. The percent increase of agglomeration rate is estimated by mathematical modeling for particles smaller than five microns in diameter. Particulate collection efficiency with or without agglomeration is presented. Experimental results in a high temperature cyclone are presented. The output dust loading varied from 0.025 to 5 grains per cubic foot (0.057–11 g/m³) as the input dust loading is increased from 4 to 35 grains per cubic foot (9.2–80g/m³) of gas flow.