Bioassay for determining sensitivity to sulfosulfuron on seven plant species

This study presents a bioassay procedure, based on the root and shoot growth parameters, for the determination of the herbicide sulfosulfuron (1-(4,6 dimethoxypyrimidin-2-yl)-3-(2-ethylsulfonylimidazo[1,2-a]pyridin-3-ylsulfonil)urea) sensitivity on seven vegetal species. Plant response to sulfosulfuron was calculated with the equations fitted to the root growth data as a function of the logarithm of the herbicide concentration by non-linear regression and was used to calculate the doses for 10, 30 and 50% inhibition of root growth (EC10, EC30 and EC50). The results indicate that the phytotoxic effect of sulfosulfuron in all the species assayed followed the order: flax > maize > onion > vetch > lepidium sativum > tomato > barley. These species showed phytotoxicity at low levels of sulfosulfuron and flax appeared to be the most susceptible species to sulfosulfuron (0.001 mg/L).     

Analysis of aerosol particles and coarse particulate matter concentrations in Chillán, Chile, 2001-2003

Daily particle samples were collected in Chillán, Chile, at six urban locations from September 1, 2001, through September 30, 2003. Aerosol samples were collected using monitors equipped with a Sierra Andersen 246-b cyclone inlet on Teflon filters. Average concentrations of coarse particulate matter (PM10) for the 2001-2003 period ranged from 43.4 microg/m3 to 81.8 microg/m3 across the six sites. Annual PM10 concentration levels exceeded the European Union concentration limits. Mean PM10 levels during the cold season (April through September) were more than twice as high as those observed in the warm season (October through March). Average contributions to PM10 from organic matter, soil dust, nitrate (NO3-), elemental carbon, ammonium (NH4+), and sulfate (SO4(2-)) were 31%, 27%, 11%, 8%, 7%, and 5%, respectively. The chemical analyses indicated that carbonaceous substances were the most abundant components of PM10 in cold months, whereas crustal material was the most abundant component of PM10 during warm months. Higher concentration levels were observed in the downtown area suggesting a clear anthropogenic origin, whereas in the rural sites the source was mainly natural, such as resuspended soil dust associated with traffic on unpaved roads and agricultural activities.     

Local air quality management as a risk management process: assessing, managing and remediating the risk of exceeding an air quality objective in Great Britain

Air quality is managed in Great Britain via an effects-based, risk management process designed to provide a dynamic solution to public health issues associated with elevated concentrations of seven specified air pollutants. This paper is concerned with an examination and evaluation of the process of Local Air Quality Management (LAQM) in Great Britain from the late 1980s to date as a risk management process. The statutory basis of LAQM process is provided by the Environment Act 1995. The Act provides a framework in which national and local actions are required to identify and remediate areas of poor air quality. Within this framework, the implementation of the process at national and local levels is considered, leading to an identification and assessment of risks in the formulation and implementation of air quality management policy and practice. Local Authorities began the process of Review and Assessment in 1999 and the first round of the process concluded in 2001. Following this, some 129 Local Authorities declared one or more Air Quality Management Areas (AQMAs). The Review and Assessment elements of the framework were subjected to an evaluation in 2001 and the essential elements of it were confirmed as fit for purpose. The evaluation led to a confirmation of the process of LAQM but also a simplification based on the experience of Round 1. Now, a two step process is required comprising of an Updating and Screening Assessment and, where a risk of exceeding an Air Quality Objective (AQO) is identified, a Detailed Assessment follows. The Government has identified a time scale for Review and Assessment through to 2010 and also introduced the requirement of a regular Progress Report in order that a Local Authority is able to address routine matters of air quality management. The risks inherent in epidemiological or scientific uncertainty are factored into the LAQM process at an early stage of the process and, by identifying the risks and subjecting them to regular review, the process provides a 'level playing field' across spatial and temporal scales. Whilst the process of LAQM described in this paper has been developed for Great Britain, the generic elements of the process are applicable to other countries challenged by air pollution problems which require both national and local action to resolve them.     

Limits of thermoluminescence dosimetry using quartz extracted from recent building materials in urban settlements

The luminescence of quartz extracted from recently fired building material is known to detect doses of few mGy and can be successfully employed in the case of large scale radiation exposures due to nuclear accidents or terrorist acts. One brick and two tiles (50-80 years range) collected from an urban settlement were used to test the realistic minimum detectable dose limits of retrospective luminescence dosimetry. Independent methods like alpha counting, beta dosimetry, gamma spectrometry and flame photometry were used for the annual dose assessment. Two approaches were employed for the evaluation of the total accrued dose: regenerative dose and additive dose. The former allows the assessment of doses due to anthropogenic sources of radiation as low as approximately 12 mGy by using 10-year-old samples, but it can be applied only in samples showing no sensitisation. The latter can be applied to any sample, however, the related uncertainty is higher and minimum detectable anthropogenic dose in young samples amounts to 20 mGy.     

Conceptual approaches for the development of dynamic specific activity models of 14C transfer from surface water to humans

Carbon-14 is a particularly interesting radionuclide from the perspective of dose estimation. Many nuclear facilities, including power reactors, release 14C into the environment, and much of this is as 14CO2. This mixes readily with stable CO2, and hence enters the food chain as fundamental biomolecules. This isotopic mixing is often used as the basis for dose assessment models. The present model was developed for the situation of 14C releases to surface waters, where there are distinct changes in the water 14C activity concentrations throughout the year. Complete isotopic mixing (equilibrium) cannot be assumed. The model computes the specific activity (activity of 14C per mass of total C) in water, phytoplankton, fish, crops, meat, milk and air, following a typical irrigation-based food-chain scenario. For most of the biotic compartments, the specific activity is a function of the specific activity in the previous time step, the specific activity of the substrate media, and the C turnover rate in the tissue. The turnover rate is taken to include biochemical turnover, growth dilution and mortality, recognizing that it is turnover of C in the population, not a tissue or an individual, that is relevant. Attention is paid to the incorporation of 14C into the surface water biota and the loss of any remaining 14CO2 from the surface water-air interface under its own activity concentration gradient. For certain pathways, variants in the conceptual model are presented, in order to fully discuss the possibilities. As an example, a new model of the soil-to-plant specific activity relationship is proposed, where the degassing of both 14C and stable C from the soil is considered. Selection of parameter values to represent the turnover rates as modeled is important, and is dealt with in a companion paper.     

Radiobiological monitoring of striped field mouse populations in the Moscow recreation forest "Kuzminki"

The results of radiometric and haematological studies of striped field mice (Apodemus agrarius) sampled over the years 1995-2003 from the territory of the preserved radioactive waste burial (RWB), which is located in the Moscow recreation forest "Kuzminki", are presented and discussed in the paper. It was shown that the level of 90Sr-90Y content in mice sampled from the RWB area varies within the range of 0-1200 Bq/kg with an average of 98.7+/-21.5 Bq/kg. The content of 90Sr-90Y in the body of 80% of the mice sampled from the RWB area was below 100 Bq/kg. Only in 4% of the sampled mice, the 90Sr-90Y specific radioactivity was above 300 Bq/kg. Haematological indications of the animals sampled from the RWB area were within the range of normal physiological fluctuations. Nevertheless, a slight but statistically significant increase in the average amount of erythrocytes and the average percentage of banded neutrophils was registered in peripheral blood of the mice.     

234U and 230Th determination by FIA-ICP-MS and application to uranium-series disequilibrium in marine samples

A 234U and 230Th determination method based on an extraction chromatographic separation on a flow injection system coupled to a quadruple ICP-MS was developed. Two-milliliter UTEVA (Eichrom Co.) cartridges were applied as separation tool and 236U and 229Th as spikes. Loading and washing steps were carried out in 3 M HNO3 solution and 0.05 M ammonium oxalate applied to elute both uranium and thorium. The method was applied initially to the IAEA-327 soil reference sample and NIST SRM 4357 ocean sediment reference material, with the obtained 234U and 230Th concentrations in agreement with the reference levels. Samples from a deep-sea sediment core (2450 m water depth) were analyzed and based on 230Th/234U dating, a mean sedimentation rate of 3.3 cm ky(-1) was calculated. Samples from two sediment layers were also dated by 14C-AMS and the observed ages agree with the 230Th/234U results.     

Revision and meta-analysis of selected biosphere parameter values for chlorine, iodine, neptunium, radium, radon and uranium

There is a continual supply of new experimental data that are relevant to the assessment of the potential impacts of nuclear fuel waste disposal. In the biosphere, the traditional assessment models are data intensive, and values are needed for several thousand parameters. This is augmented further when measures of central tendency, statistical dispersion, correlations and truncations are required for each parameter to allow probabilistic risk assessment. Recent reviews proposed values for 10-15 key element-specific parameters relevant to (36)Cl, (129)I, (222)Rn, (226)Ra, (237)Np and (238)U, and some highlights from this data update are summarized here. Several parameters for Np are revised downward by more than 10-fold, as is the fish/water concentration ratio for U. Soil solid/liquid partition coefficients, Kd, are revised downward by 10-770-fold for Ra. Specific parameters are discussed in detail, including degassing of I from soil; sorption of Cl in soil; categorization of plant/soil concentration ratios for U, Ra and Np; Rn transfer from soil to indoor air; Rn degassing from surface water; and the Ca dependence of Ra transfers.     

Biogeochemical signatures in the lichen Hypogymnia physodes in the mid Urals

Multi-element content and uranium (U) isotopes were investigated in the lichen Hypogymnia physodes (native and transplants) sampled across a 60-km transect, centred on Karabash smelter town, from Turgoyak Lake (SW) to Kyshtym (NE) to investigate the origin of U. Kyshtym was the site of a major nuclear accident in 1957. (234)U/(238)U activity ratios in native thalli sampled during July 2001 were within the natural isotopic ratio in minerals. Uranium/thorium (U/Th) ratios were higher in native thalli towards the NE (average 0.73) than those in the SW (average 0.57). Element signatures in native thalli and transplants suggest U was derived from fossil fuel combustion from Karabash and sources lying further to the east. Systematic and significant U enrichment indicative of a nuclear fuel cycle source was not detected in any sample. Element signatures in epiphytic lichen transplants and native thalli provide a powerful method to evaluate U deposition.     

I-Risk: development of an integrated technical and management risk methodology for chemical installations

This paper presents an integrated quantitative risk assessment method for hazardous installations, taking into account management as well as technical design and producing risk level measures. The key components of the I-Risk methodology are the technical model, the management model and their interface. The technical model consists of developing a master logic diagram (MLD) delineating the major immediate causes of loss of containment (LOC) and associated quantitative models for assessing their frequency. The management model consists of the tasks, which must be carried out systematically in the primary business functions (such as operations, emergency operations, maintenance and modifications). A management audit quantifies the quality of these management tasks. The management–technical interface modifies certain parameters of the technical model on the basis of the quality of the safety management system of the specific installation. The methodology is exemplified through its application to the risk assessment of an ammonia storage facility. A detailed technical model simulating the response of the system to various initiating events is developed along with a detailed management model simulating the influence of the plant-specific management and organisational practices. The overall effect is quantified through the frequency of release of ammonia as a result of a loss of containment in a storage tank and in a pipeline.