Verification of diffusive and pumped samplers for volatile organic compounds using a controlled atmosphere test facility

There is a requirement to verify the performance of sorbent-based passive or active samplers and to extend their use, where possible, to monitor volatile organic compounds (VOCs) that are known to be photochemical ozone pre-cursors or are relevant to the activities of the petrochemical industry. We report measurements of the 14-day diffusive uptake rates for the VOCs: i-butane (2-methyl propane), n-butane, i-pentane (2-methyl butane), n-pentane, n-hexane, benzene, toluene, and m-xylene (at environmental level concentrations) for industry standard axial samplers (Perkin–Elmer-type samplers) containing the sorbents Carbopack-X, -Z, -B or Tenax-TA. We also present data on back-diffusion, blank levels, and storage for the above sorbents, and describe the simultaneous use of the sorbent Carbopack-X for pumped sampling of certain VOCs. The results were obtained by dosing samplers in a controlled atmosphere test facility (CATFAC) operating under well-defined conditions of concentration, nominal temperature of 20 °C, wind speed of 0.5 m s^?1, and relative humidities of 0% and 80%. Field measurements were also obtained to provide supplementary data to support the laboratory study. Results are compared to existing published data, where these are available.     

Aspects of planning in Scotland: an introductory paper

This paper provides an outline of the development planning and development control systems which operate in Scotland, illustrating that while they share common principles and objectives with the equivalent systems in England and Wales there are a number of important differences both in law and more especially in practice to be appreciated. Future changes are outlined both in relation to the statutory planning system as well as in the broader fields of housing, economic development and the countryside.     

Sustainable urban planning and the brownfield development process in the United Kingdom: Lessons from the Thames Gateway

Over recent decades urban and regional development agendas in the United Kingdom have become dominated by the discourses of sustainable development, holistic regeneration and community capacity-building. It is in this context that brownfield development has emerged as a core feature in strategies to regenerate urban areas. Bringing brownfields back into use tends to be, a priori, presented as a 'good thing' that will have broader economic, environmental and social benefits. This paper assesses the role that brownfield development plays in urban and regional policy agendas in the UK. It begins by identifying the rationales for, and concerns associated with, the brownfield development process in the UK, before discussing the trajectories of policy under the New Labour government since 1997. It argues that at present too much is expected from brownfield-led regeneration programmes and that wider benefits will only accrue if these programmes are embedded within a wider and more comprehensive set of development projects and policy agendas.     

Variation in root density along stream banks

While it is recognized that vegetation plays a significant role in stream bank stabilization, the effects are not fully quantified. The study goal was to determine the type and density of vegetation that provides the greatest protection against stream bank erosion by determining the density of roots in stream banks. To quantify the density of roots along alluvial stream banks, 25 field sites in the Appalachian Mountains were sampled. The riparian buffers varied from short turfgrass to mature riparian forests, representing a range of vegetation types. Root length density (RLD) with depth and aboveground vegetation density were measured. The sites were divided into forested and herbaceous groups and differences in root density were evaluated. At the herbaceous sites, very fine roots (diameter < 0.5 mm) were most common and more than 75% of all roots were concentrated in the upper 30 cm of the stream bank. Under forested vegetation, fine roots (0.5 mm < diameter < 2.0 mm) were more common throughout the bank profile, with 55% of all roots in the top 30 cm. In the top 30 cm of the bank, herbaceous sites had significantly greater overall RLD than forested sites (alpha = 0.01). While there were no significant differences in total RLD below 30 cm, forested sites had significantly greater concentrations of fine roots, as compared with herbaceous sites (alpha = 0.01). As research has shown that erosion resistance has a direct relationship with fine root density, forested vegetation may provide better protection against stream bank erosion.     

Reproductive endocrine disruption in smallmouth bass (Micropterus dolomieu) in the Potomac River basin: spatial and temporal comparisons of biological effects

A high prevalence of intersex or testicular oocytes (TO) in male smallmouth bass within the Potomac River drainage has raised concerns as to the health of the river. Studies were conducted to document biomarker responses both temporally and spatially to better understand the influence of normal physiological cycles, as well as water quality and land-use influences. Smallmouth bass were collected over a 2-year period from three tributaries of the Potomac River: the Shenandoah River, the South Branch Potomac and Conococheague Creek, and an out-of-basin reference site on the Gauley River. The prevalence of TO varied seasonally with the lowest prevalence observed in July, post-spawn. Reproductive maturity and/or lack of spawning the previous spring, as well as land-use practices such as application of manure and pesticides, may influence the seasonal observations. Annual, seasonal, and site differences were also observed in the percentage of males with measurable concentrations of plasma vitellogenin, mean concentration of plasma vitellogenin in females, and plasma concentrations of 17β-estradiol and testosterone in both sexes. Bass collected in the South Branch Potomac (moderate to high prevalence of TO) had less sperm per testes mass with a lower percentage of those sperm being motile when compared to those from the Gauley River (low prevalence of TO). An inverse relationship was noted between TO severity and sperm motility. An association between TO severity and wastewater treatment plant flow, percent of agriculture, total number of animal feeding operations, the number of poultry houses, and animal density within the catchment was observed.     

Percentile estimation using variable censored data

Much progress has been made in recent years to address the estimation of summary statistics, using data that are subject to censoring of results that fall below the limit of detection (LOD) for the measuring instrument. Truncated data methods (e.g., Tobit regression) and multiple-imputation are two approaches for analyzing data results that are below the LOD. To apply these methods requires an assumption about the underlying distribution of the data. Because the log-normal distribution has been shown to fit many data sets obtained from environmental measurements, the common practice is to assume that measurements of environmental factors can be described by log-normal distributions. This article describes methods for obtaining estimates of percentiles and their associated confidence intervals when the results are log-normal and a fraction of the results are below the LOD. We present limited simulations to demonstrate the bias of the proposed estimates and the coverage probability of their associated confidence intervals. Estimation methods are used to generate summary statistics for 2,3,7,8-tetrachloro dibenzo-p-dioxin (2,3,7,8-TCDD) using data from a 2001 background exposure study in which PCDDs/PCDFs/cPCBs in human blood serum were measured in a Louisiana population. Because the congener measurements used in this study were subject to variable LODs, we also present simulation results to demonstrate the effect of variable LODs on the multiple-imputation process.     

Threatened and Endangered Species: At What Cost? The Corps of Engineers Looks at Expenditures and Priorities

Current political conditions, primarily budgetary uncertainty, and the related reluctance to make funding commitments for future generations, have raised questions about the costs of conservation and environmental protection that have not previously been asked. As Federal investments are scrutinized and budgets become ever more constrained, the costs associated with environmental requirements could begin to be of greater importance and to influence decisions on Federal projects. In response to concerns about the U.S. Army Corps of Engineers (Corps) spending under the Endangered Species Act (P.L. 93-205) (ESA), a limited investigation was performed to determine the accuracy of reported Corps expenditures. The investigation showed that, for particular groups of species, actual conservation costs for threatened and endangered species may be twice the amounts previously reported in the annual ESA expenditure reporting to the U.S. Fish and Wildlife Service. In light of this finding, the Corps has sought a means to provide more accurate and consistent reporting of expenditures for addressing threatened and endangered species. A Species Costs Template (template) has been developed to identify the types and magnitude of costs related to the ESA and to counteract the impediments (legal, institutional, and practical) to underreporting costs. The template will be used by the Corps for reporting ESA costs beginning with Fiscal Year 2005 (FY05) (reported in January 2006). Five broad categories of expenditures (effects determination costs, ESA protection and conservation costs, equipment costs, opportunity costs, and other species costs) are identified by the template.     

Surface geophysical exploration: developing noninvasive tools to monitor past leaks around Hanford’s tank farms

A characterization program has been developed at Hanford to image past leaks in and around the underground storage tank facilities. The program is based on electrical resistivity, a geophysical technique that maps the distribution of electrical properties of the subsurface. The method was shown to be immediately successful in open areas devoid of underground metallic infrastructure, due to the large contrast in material properties between the highly saline waste and the dry sandy host environment. The results in these areas, confirmed by a limited number of boreholes, demonstrate a tendency for the lateral extent of the underground waste plume to remain within the approximate footprint of the disposal facility. In infrastructure-rich areas, such as tank farms, the conventional application of electrical resistivity using small point-source surface electrodes initially presented a challenge for the resistivity method. The method was then adapted to directly use the buried infrastructure, specifically the steel-cased wells that surround the tanks, as “long” electrodes for both transmission of electrical current and measurements of voltage. Overcoming the drawbacks of the long electrode method has been the focus of our work over the past 7 years. The drawbacks include low vertical resolution and limited lateral coverage. The lateral coverage issue has been improved by supplementing the long electrodes with surface electrodes in areas devoid of infrastructure. The vertical resolution has been increased by developing borehole electrode arrays that can fit within the small-diameter drive casing of a direct push rig. The evolution of the program has led to some exceptional advances in the application of geophysical methods, including logistical deployment of the technology in hazardous areas, development of parallel processing resistivity inversion algorithms, and adapting the processing tools to accommodate electrodes of all shapes and locations. The program is accompanied by a full set of quality assurance procedures that cover the layout of sensors, measurement strategies, and software enhancements while insuring the integrity of stored data. The data have been shown to be useful in identifying previously unknown contaminant sources and defining the footprint of precipitation recharge barriers to retard the movement of existing contamination.     

The informal rules of working relationships

It was expected that there would be informal rules of several kinds for working relationships. In the first study subjects rated 33 common rules and a number of relationship-specific rules for three work roles. It was found that certain rules were strongly endorsed for work-mates, superiors and subordinates. These provide a maintenance function by regulating general and relationship-specific sources of conflict. Rules about cooperation, help and fairness applied strongly to work-mates, rules about consideration and skilful use of power to supervisors, rules about using initiative and accepting orders and criticism to subordinates. Rules about reward were also obtained and these tended to be task-focused rather than intimacy sustaining. In the second study one hundred and twenty-four subjects rated the degree of dissatisfaction which they would feel for 11 types of rule violation by each of four work colleagues varying in degree of intimacy. Some level of dissatisfaction was expressed for each rule violation particularly maintenance rules, and the degree of expressed dissatisfaction increased with increased closeness to the work colleague. Study I was replicated in three other countries — Italy, Hong Kong and Japan, and cross-cultural comparisons were made. While there was some cross-cultural consistency for certain maintenance rules, there were cultural differences both in the type of rules endorsed and the strength of endorsement. Japanese relationships in particular were most dissimilar to other countries, characterized by greater homogeneity of overall rule structure within the four work roles, and by lower levels of intimacy and emotional expressiveness towards the other person in each relationship.