Evaluation of a soil‐amendment process demonstration for reducing the bioavailability of lead

The U.S. Environmental Protection Agency (EPA) evaluated an in‐situ application of a soil‐amendment process at a residential site that was contaminated with lead. The goal of the evaluation was to determine if the soil‐amendment process resulted in lower concentrations of bioavailable lead in the contaminated soils. The relative bioavailability of lead (bioaccessible lead) was measured by an in vitro test procedure that uses a highly acidic extraction procedure to simulate human digestive processes. The soil‐amendment demonstration showed that the 11.2 percent mean reduction in bioavailable lead concentration between untreated and treated soils was not statistically different. © 2002 Wiley Periodicals, Inc.     

Swamp reclamation in tropical monsoon regions by appropriate refuse landfilling

Summary This paper is based on a research study to evaluate the feasibility of reclaiming low-lying swamplands by filling them with refuse, rather than with dirt, sand or other inert materials. A supplementary study was also initiated to prepare a preliminary evaluation of disposing of solid waste from the Bangkok Metropolis region. This included a preliminary assessment of available filling areas and of costs for filling them, together with projected values of reclaimed land. The latter study was included to determine if a feasibility study for utilising refuse landfilling for Bangkok solid-waste disposal is warranted, and to prepare the feasibility study terms of reference if so justified. Results of the literature review, practices of refuse landfilling in swamps, and methods and materials employed in conduct of the study are described. This is followed by evaluations of the feasibility of disposing solid wastes utilising swamplands, an environmental analysis of the same, and the conclusions of the study.The authors are Consulting Engineers at Seatec International, Bangkok. The views in this paper are those of the authors and do not necessarily reflect World Bank policies.     

Spectrophotometric determination of uranium with arsenazo-III in perchloric acid

A short, sensitive and reliable spectrophotometric method, which has advantages over all known "wet chemistry" methods for uranium determination with regard to tolerance to common interferences, has been developed for the determination of uranium. Selectivity, molar absorptivity and the determination range of uranium have been enhanced by using 0.07% arsenazo-III as a chromogenic reagent. The use of 3 mol dm(-3) perchloric acid as a medium of determination was found to be excellent in terms of good solvent compatibility on dilution, destruction of organic contamination and simplicity of operation. The uranium-arsenazo-III complex formed instantly, and was found to be stable for more than 3 weeks with constant absorbance. Beer's law was obeyed up to a uranium concentration of 16 microg g(-1), with a molar absorptivity at 651 nm of 1.45x10(5) mol(-1) dm(3) cm(-1) at 24+/-2 degrees C. Only phosphate and citrate at 70-fold excess over uranium interfere seriously, whereas other anions studied could be tolerated up to a 70-fold excess over uranium. Of the cations studied, only Mn(II), Co(II), Ni(II), Cu(II) and Cr(III) decreased the normal absorbance of the complex. Iron(III), Ce(III) and Y(III) enhanced the absorbance. Other cations studied did not affect the absorbance up to a 50-fold excess. The accuracy was checked by determining uranium from standard solutions in the range 10-50 microg g(-1). It was found to be accurate with a 96.0-98.6% recovery rate. The method has been successfully applied to standard reference materials and ore samples at microg g(-1) levels.     

Modelling nitrogen saturation and carbon accumulation in heathland soils under elevated nitrogen deposition

A simple model of nitrogen (N) saturation, based on an extension of the biogeochemical model MAGIC, has been tested at two long-running heathland N manipulation experiments. The model simulates N immobilisation as a function of organic soil C/N ratio, but permits a proportion of immobilised N to be accompanied by accumulation of soil carbon (C), slowing the rate of C/N ratio change and subsequent N saturation. The model successfully reproduced observed treatment effects on soil C and N, and inorganic N leaching, for both sites. At the C-rich upland site, N addition led to relatively small reductions in soil C/N, low inorganic N leaching, and a substantial increase in organic soil C. At the C-poor lowland site, soil C/N ratio decreases and N leaching increases were much more dramatic, and soil C accumulation predicted to be smaller. The study suggests that (i) a simple model can effectively simulate observed changes in soil and leachate N; (ii) previous model predictions based on a constant soil C pool may overpredict future N leaching; (iii) N saturation may develop most rapidly in dry, organic-poor, high-decomposition systems; and (iv) N deposition may lead to significantly enhanced soil C sequestration, particularly in wet, nutrient-poor, organic-rich systems.     

Re‐evaluating the Contribution of Social Capital in Achieving Sustainable Development

The last decade has seen considerable interest in the concept of social capital and there have been a number of publications focused around the concept. A wide range of claims have been made for the analytic potential of social capital leading some to question the concept's continued value. We think that the concept still has considerable value if used in a careful and rigorous way. We further think that the concept has particular value when considering policy for sustainable development. However, just as sustainable development is a multi‐faceted concept, this application requires a multi‐faceted reading of social capital. Having concluded that a clearer typology of social capital is needed, we propose a threefold typology, adding the new category of ‘bracing’ social capital to the more commonly used distinction between ‘bonding’ and ‘bridging’ social capital. We also address the issues of what social capital can do and how it actually works, specifically in the context of policy for sustainable development.     

ALGAE IN THE SPOON RIVER,ILLINOIS 1971–19721

ABSTRACT: As a part of a water quality survey of the Spoon River, Illinois, algal genera were identified and their densities were enumerated. Weekly samples were collected at five stations starting on June 1, 1971. This report presents the first year's results. Algal densities for each station were found to be distributed geometrically normal. Total algal densities increased as water progressed downstream. Although water temperature has been observed to be an important factor affecting the density and the composition of algae in streams, attempts to correlate algal densities with temperatures for the Spoon River were not fruitful. Correlations of algal densities with dissolved oxygen, flow, and coliform densities also could not be made. The dominant genera observed were Cyclotella, Navicula, Scenedesmus, and Euglena. On the average diatoms accounted for 87% of all algae counts. The average diversity indices varied about 1.0 to 1.5 for five stations. There did not appear to be any advantage in the use of diversity index over that of algal density and genera richness in characterizing algae in the Spoon River.     

Phenotypic assortment by body shape in wild-caught fish shoals

Phenotypic variation plays a critical role in determining the structural organisation and ecological function of wild populations. Animal groups are often structured according to factors such as species, sex, body size and parasite load, but it is unclear whether body shape also influences patterns of social organisation, and thus contributes to population phenotypic structure. Here, we use geometric morphometric analyses to determine whether wild-caught shoals of a freshwater fish, the western rainbowfish (Melanotaenia australis), are structured according to body size and shape. Using randomisation analyses, we show that the level of variation in size and shape observed in natural group assemblages is lower than that expected under a null model of random shoal composition. In addition, we found evidence of further phenotypic structuring along an upstream-downstream environmental gradient. The putative benefits of morphological assortment include a reduction in predation risk (due to prey oddity and predator confusion effects) and increased hydrodynamic or foraging efficiency. We suggest that morphological variation is a neglected component of population social organisation that can affect population processes, such as patterns of gene flow, and ecological interactions, such as predator-prey dynamics.