Effect of humic acid on water chemistry, bioavailability and toxicity of aluminium in the freshwater snail, Lymnaea stagnalis, at neutral pH

The influence of humic acid on the water chemistry of environmentally relevant concentrations of Al at neutral pH was studied, together with its effect on the bioavailability and toxicity of Al in Lymnaea stagnalis. Humic acid significantly reduced the loss of Al from the water and increased the fraction of filterable Al, although this was a relatively small fraction of total Al. Filterable Al concentration in the presence or absence of humic acid was independent of initial Al concentration. Humic acid only partly reduced toxicity, as observed by a reduction in behavioural suppression, and had no effect on the level of Al accumulated in tissues. These results suggest that humic acid maintains Al in a colloidal form that is bioavailable to L. stagnalis. However, these colloidal Al-humic acid species were less toxic since behavioural toxicity was reduced. Humic acid may play an important role in limiting the toxicity of Al to freshwater organisms.     

Recent trends and developments in dialogue on radioactive waste management: experience from the UK

This paper highlights some recent trends and developments in dialogue on radioactive waste management in the UK. In particular, it focuses on the use of dialogue around options for the management of risk, and describes techniques for stakeholder dialogue in the field of radioactive waste management. The paper summarises past and on-going experience in the UK, and provides an overview of some practical examples from decommissioning of the former reprocessing facility at Dounreay in Scotland. In common with developments and trend in other countries, the UK has moved to a position where there is now widespread recognition that radioactive waste management requires not only sound technical assessment of risk, but also public participation, consultation and stakeholder dialogue on proposed solutions and the associated risks. In fact, the shift of position has arguably been quite pronounced, with formal procedures to identify, clarify and integrate stakeholders' issues and concerns within the decision-making processes. Experience suggests that citizens are capable of engaging with complex technical issues such as radioactive waste. Indeed, the earlier in the decision-making process that public and stakeholder engagement (PSE) occurs--for example, on the consideration of options and alternatives--the greater the chance of reaching a successful outcome that properly reflects the values and opinions of stakeholders. In the UK, the assessment of alternative waste management options is increasingly being addressed through Best Practical Environmental Option (BPEO) studies. Responses to stakeholder engagement processes and experience of conducting BPEO studies emphasise that consultation must be open, transparent, deliberative and inclusive. However, while early consideration of generic approaches and option choices is necessary to generate a climate of openness and understanding, it remains essential to fully engage with local stakeholder and community groups to consider issues associated with proposed developments at a site-specific level. An interesting area where further attention may be warranted is the use in final decision-making of the results from participatory processes such as BPEO studies. Demonstrating clearly that participants' views have influenced decisions appears to be essential for retaining legitimacy and trust, confidence and goodwill.     

Toward cleaner production of hot dip galvanizing industry in China

China has now the largest annual outputs of galvanized steel and the most amount of galvanizing plants in the world. However, with obsolete technology, the hot dip galvanizing industry has been proved as one of the industries, which consume large amounts of raw materials and energy, produce numerous pollutants and causes serious contamination in China. Cleaner Production in the hot dip galvanizing industry is now the only way to achieve the sustainable development of hot dip galvanizing industry. The implementation of the Common Fund for Commodities (CFC) project: The Transfer of Technology and Promotion of demand: Batch hot dip galvanizing in China launched by International Zinc Association (IZA) is introduced in this paper, The Best Available Technologies of operation, energy and environmental management in the world are also introduced. With the implementation of the project, an assessment system of Cleaner Production and a training system have been developed and implementation of technical updating to the demonstration plant shows that the reduction of zinc loss, and water and fuel cost savings can be achieved. It is believed that the methodology of the project can be applied throughout China as the galvanizers see the cost benefits.     

Prenatal diagnosis using interphase fluorescence in situ hybridization (FISH): 2-year multi-center retrospective study and review of the literature

Since 1993, the position of the American College of Medical Genetics (ACMG) has been that prenatal interphase fluorescence in situ hybridization (FISH) is investigational. In 1997, the FDA cleared the AneuVysion^® assay (Vysis, Inc.) to enumerate chromosomes 13, 18, 21, X and Y for prenatal diagnosis. Data is presented from the clinical trial that led to regulatory clearance (1379 pregnancies) and from retrospective case review on 5197 new pregnancies. These studies demonstrated an extremely high concordance rate between FISH and standard cytogenetics (99.8%) for specific abnormalities that the AneuVysion assay is designed to detect. In 29 039 informative testing events (6576 new and 22 463 cases in the literature) only one false positive (false positive rate=0.003%) and seven false negative results (false negative rate=0.024%) occurred. A historical review of all known accounts of specimens tested is presented (29 039 using AneuVysion and 18 275 specimens tested with other probes). These performance characteristics support a prenatal management strategy that includes utilization of FISH for prenatal testing when a diagnosis of aneuploidy of chromosome 13, 18, 21, X or Y is highly suspected by virtue of maternal age, positive maternal serum biochemical screening or abnormal ultrasound findings. Copyright © 2001 John Wiley & Sons, Ltd.     

Metabolic rate throughout the annual cycle reveals the demands of an Arctic existence in great cormorants

Aquatic endotherms living in polar regions are faced with a multitude of challenges, including low air and water temperatures and low illumination, especially in winter. Like other endotherms from cold environments, Great Cormorants (Phalacrocorax carbo) living in Arctic waters were hypothesized to respond to these challenges through a combination of high daily rate of energy expenditure (DEE) and high food requirements, which are met by a high rate of catch per unit effort (CPUE). CPUE has previously been shown in Great Cormorants to be the highest of any diving bird. In the present study, we tested this hypothesis by making the first measurements of DEE and foraging activity of Arctic-dwelling Great Cormorants throughout the annual cycle. We demonstrate that, in fact, Great Cormorants have surprisingly low rates of DEE. This low DEE is attributed primarily to very low levels of foraging activity, particularly during winter, when the cormorants spent only 2% of their day submerged. Such a low level of foraging activity can only be sustained through consistently high foraging performance. We demonstrate that Great Cormorants have one of the highest recorded CPUEs for a diving predator; 18.6 g per minute submerged (95% prediction interval 13.0-24.2 g/min) during winter. Temporal variation in CPUE was investigated, and highest CPUE was associated with long days and shallow diving depths. The effect of day length is attributed to seasonal variation in prey abundance. Shallow diving leads to high CPUE because less time is spent swimming between the surface and the benthic zone where foraging occurs. Our study demonstrates the importance of obtaining accurate measurements of physiology and behavior from free-living animals when attempting to understand their ecology.     

Spatial and temporal heterogeneities in the contact behaviour of rabbits

It is becoming increasingly evident that the social behaviour of many group-living species is more complex than previously assumed and that free mixing of individuals, even within social groups, is rare. This has important implications for ecological processes, such as disease transmission, which are dependent on interactions between individuals. European wild rabbits (Oryctolagus cuniculus) have been considered traditionally as highly sociable animals that mix freely within groups but interact less frequently between groups. We deployed proximity logging devices to quantify the intra- and inter-group contact behaviour of free-living wild rabbits in two populations in a temperate region of Australia. Altogether, 126 rabbits were fitted with proximity loggers at least once during the study. Radio-tracking was carried out alongside proximity data collection to determine the space use of rabbit social groups within the study sites. On average, a rabbit made only 1.54 ± 0.23 (SE) (median = 0.54) contacts per day with each other rabbit carrying a proximity logger in its social group, and the mean daily contact duration was 202 ± 38 s/day (SE) (median = 29 s). Despite the high degree of home range overlap between the neighbouring social groups, inter-group contacts were highly infrequent and brief. Our results demonstrated considerable spatial and temporal heterogeneities in the contact behaviour between individual rabbits, both between populations and between and within social groups in the same population. Such variations in the social organisation of rabbits are likely to create complex patterns of disease transmission through direct contact and may contribute towards observed heterogeneities in the effects of disease on wild rabbit populations.     

Modelling and mapping topographic variations in forest soils at high resolution: A case study

This article examines the utility of a digitally derived cartographic depth-to-water (DTW) index to model and map variations in drainage, vegetation and soil type and select soil properties within a forested area (40 ha) of the Swan Hills, Alberta, Canada. This index was derived from a LiDAR (Light Detection and Ranging) derived digital elevation model (DEM), with at least 1 ground return per m². The resulting DTW pattern was set to be zero along all DEM-derived flow channels, each with a 4 ha flow-initiation threshold. Soil type (luvisol, gleysol, mesisol), drainage type (very poor to excessive), vegetation type (hydric to xeric) and forest floor depth were determined along hillslope transects. These determinations conformed more closely to the DEM-derived log₁₀(DTW) variations (R² > 60%) than to the corresponding variations of the widely used topographic wetness index (TWI) (R² < 25%). Setting log₁₀(DTW) thresholds to represent the wet to moist to dry transitions between vegetation, drainage and soil type enabled a high-resolution mapping of these types across the study area. Also determined were soil moisture content, coarse fragment and soil particle composition (sand, silt, clay), pH, total C, N, S, P, Ca, Mg, K, Fe, Al, Mn, Zn, and available Ca, Mg, K, P and NH₄, by soil layer type and depth. Most of these variables were also more correlated with log₁₀(DTW) than with TWI, with and without soil layer depth as an additional regression variable. These variables are, therefore, subject to topographic controls to at least some extent, and can be modelled and mapped accordingly, as illustrated for soil moisture, forest floor depth and pH across the study area, from ridge tops to depressions. Further examinations revealed that the DEM-produced DTW and TWI patterns complemented one another, with DTW delineating soils in relation to local water-table influences, and with TWI delineating where the water would flow and accumulate.     

VELOCITY DISTRIBUTIONS IN STREAMBED SIMULATION CULVERTS USED FOR FISH PASSAGE1

ABSTRACT: Stream crossings designed to simulate a natural streambed inside a culvert are commonly used to meet criteria where fish passage is required. Currently, there has been little research that quantitatively examines the flow patterns within these streambed simulation culverts. A model is presented that estimates the percent of a cross section that is within the swimming ability of juvenile fish developed from velocity measurements on first‐generation stream simulation culverts — those culverts with a continuous gravel bed. The model, developed with regression techniques, uses physical and hydraulic parameters including discharge, total cross sectional area, Froude number, and relative roughness, and was tested directly against velocity distributions computed from field measurements and in a culvert design mode. Results were favorable, although larger percentage errors exist, particularly at small flow depths. The model appears to underestimate the percent of channel cross section at or below a limiting velocity, hence it is generally conservative in design mode.