Contribution of canopy leaching to sulphate deposition in a Scots pine forest

Radioactive sulphate (35SO4) was applied to the soil below a Scots pine forest on 23 June 1989, and its movement into the canopy and into throughfall and stemflow was measured over 4 months. The specific activity, Bq (mg S)(-1), of the canopy increased monotonically; uptake by current-year (1989) expanding needles was initially twice as fast as by older needles or live twigs. By 10 October the canopy average specific activity was 62 Bq (mg S)(-1). The specific activity of net throughfall (throughfall + stemflow - rain), deduced from measurements from six throughfall collectors, six stemflow collectors and two rain collectors, fell rapidly from 12.6 Bq (mg S)(-1) in late July to <1 Bq (mg S)(-1) in mid-August. The results suggest (assuming rapid equilibration of 35S with sulphate in soil) that root-derived sulphate contributed c. 3% of sulphate in net throughfall and that dry deposition of SO2 and sulphate particles contributed c. 97% of the 0.56 g S m(-2) measured in net throughfall over the period. Simultaneous measurements of SO2 at canopy height and of NH3 above and within the canopy gave mean concentrations of 5.9 and 0.86 microg m(-3), respectively, sufficient to account for the sulphate measured in net throughfall only if codeposition of NH3 and SO2 occurred to canopy surfaces. The large values of specific activity observed in July, however, indicate that throughfall composition may be closely related to recent soil input of sulphate, and that equilibrium cannot be safely assumed. The possibility of a significant contribution of soil-derived sulphate to sulphate deposition in net throughfall cannot be ruled out on the basis of this experiment.     

Chromium speciation and fractionation in ground and surface waters in the vicinity of chromite ore processing residue disposal sites

Chromium concentrations of up to 91 mg l(-1) were found by ICP-OES for ground water from nine boreholes at four landfill sites in an area of S.E. Glasgow/S. Lanarkshire where high-lime chromite ore processing residue (COPR) from a local chemical works had been deposited from 1830 to 1968. Surface water concentrations of up to 6.7 mg l(-1) in a local tributary stream fell to 0.11 mg l(-1) in the River Clyde. Two independent techniques of complexation/colorimetry and speciated isotope dilution mass spectrometry (SIDMS) showed that Cr was predominantly (>90%) in hexavalent form (CrVI) as CrO4(2-), as anticipated at the high pH (7.5-12.5) of the sites. Some differences between the implied and directly determined concentrations of dissolved CrIII, however, appeared related to the total organic carbon (TOC) content. This was most significant for the ground water from one borehole that had the highest TOC concentration of 300 mg l(-1) and at which < 3% of Cr was in the form of CrVI. Subsequent ultrafiltration produced significant decreases in Cr concentration with decreasing size fractions, e.g. <0.45 microm, < 100 kDa, <30 kDa and < 1 kDa by the tangential-flow method. As this appeared related more to concentrations of humic substances than of TOC per se, horizontal bed gel electrophoresis of freeze-dried ultrafilter retentates was carried out to further characterise the CrIII-organic complex. This showed for the main Cr-containing fraction, 100 kDa-0.45 microm, that the Cr was associated with a dark brown band characteristic of organic (humic) matter. Comparison of gel electrophoresis and FTIR results for ultrafilter retentates of ground water from this borehole with those for a borehole at another site where CrVI predominated suggested the influence of carboxylate groups, both in reducing CrVI and in forming soluble CrIII-humic complexes. The implications of this for remediation strategies (especially those based on the addition of organic matter) designed to reduce highly mobile and carcinogenic Cr(VI)O4(2-) to the much less harmful CrIII as insoluble Cr(OH)3 are discussed.     

On the Environmental Efficiency of Water Storage: the Case of a Conjunctive use of Ground and Rainwater

Rainwater harvesting, consisting in collecting runoff from precipitation, has been widely developed to stop groundwater declines and even raise water tables. However, this expected environmental effect is not self-evident. We show in a simple setting that the success of this conjunctive use depends on whether the runoff rate is above a threshold value. Moreover, the bigger the storage capacity, the higher the runoff rate must be to obtain an environmentally efficient system. We also extend the model to include other hydrological parameters and ecological damages, which respectively increase and decrease the environmental efficiency of rainwater harvesting.     

Overview of Proposal Revisions to the superfund Hazard Ranking System

The Comprehensive Environmental Response, Compensation, and Liability Act of 1980 required the federal government to establish criteria for setting priorities among releases of hazardous substances, pollutants, and contaminants. The U.S. Environmental Protection Agency responded by developing the Hazard Ranking System (HRS), which is a scoring system used to establish the National Priorities List (NPL). The Superfund Amendments and Reauthorization Act of 1986 required EPA to amend the HRS so it will more accurately assess relative risks and take into account certain specific elements of risk. On December 23,1988, EPA published in the Federal Register the proposed rule to revise the HRS.1 EPA expects to issue the final rule in 1990 after reviewing public comments. This paper describes the proposed revisions and summarizes major technical findings that support the revisions. As a result of the HRS revisions, there may be some changes in the types of sites that score high enough to be placed on the NPL. A projection of those changes is discussed.     

Indicator framework for sustainable production planning and controlling

Production facilities serve to transform raw materials into products, usually with the goal of achieving a designated output, in terms of quantity and quality, with the minimum of cost and labour. With the aid of production planning and controlling (PPC) systems, raw material inputs, and labour can be planned to achieve a determined output of products. In general, the role of environmental and social aspects is neglected in production planning processes. Because of the growing pressure from politics and customers, sustainable production of products is becoming more important. One possibility for supporting sustainable manufacturing is, to integrate sustainable aspects in the production planning process. This paper presents input and output information for current PPC systems and discusses the need for additional information necessary for sustainable PPC. For this approach, a text review of cooperate social responsibility (CSR) reporting indicators provided by the GRI was performed. Based on the text review, an input-output model has been developed for conventional and another one for sustainable PPC systems. Through the comparison of the two input-output models, challenges and requirements for sustainable PPC systems have been defined as a basis for future work and analyses.     

Assessing and managing intensification in smallholder dairy systems for food and nutrition security in Sub-Saharan Africa

Smallholder farmers play an important part in the dairy value chain in Sub-Saharan Africa. Three technological approaches have been used to improve productivity. These are through, applying agricultural ecological processes (ecological intensification), utilising modern livestock breeding (genetic intensification), and socio-economic intensification. Ecological intensification includes continuous housing of cows applying a cut-and-carry feeding system, introduction of purpose-bred forages and pastures, and the introduction of agro-forestry within the dairy systems. Genetic intensification strategies include: importation of dairy breeds such as Holstein–Friesian (HF) and cross-breeding of the indigenous breeds with HF. Training and capacity-building activities to create sustainable livelihoods have been initiated for farming and technological practices of animal husbandry, but also to enhance appropriate leadership and corporative-building skills that would create and support an enabling environment for sustainability. These improvements and initiatives in the service delivery have been championed by national governments, development partner institutions, or non-governmental organisations through different programmes. Challenges of intensification include matching management to genetic potential of imported and cross-bred improved dairy breeds, ensuring low post-harvest losses, proper utilisation, and reducing environmental impact. Using examples from Kenya, Malawi, Mozambique, Tanzania, and Zambia, this paper reviews the management and assessment approaches used in fostering smallholder dairy development strategies and dairy’s contribution to sustainable livelihoods in the face of intensification.     

An analysis of end-of-life terminology in the carbon fiber reinforced plastic industry

While many studies and reviews into the practices conducted by industry and academia to recycle and remanufacture carbon fibre-reinforced plastic (CFRP) exist, to date no investigation exists which regards the correctness of the use of the terms recycling and remanufacturing. As such, this paper seeks to analyse the CFRP reuse industry’s attempt to recycle and remanufacture manufacturing waste CFRP and end-of-life (EOL) CFRP with an emphasis on the terminology used to describe these practices. Firstly, this paper presents a justification of the importance of using EOL terminology correctly; outlining the benefits and problems associated with using the correct and incorrect terminology. This paper finds that in the case of CFRP remanufacturing, terminology is being applied incorrectly and in the case of CFRP recycling, particular care should be taken when applying the term recycled to CFRP or stating that CFRP has been recycled. Further, this paper proposes new terminology (in keeping with EU directives) which could be adopted by industry and academia working in this area. This paper also finds that in the case of remanufacture, CFRP is incapable of being remanufactured.     

Nitrogen fixation by cyanobacteria stimulates production in Baltic food webs

Filamentous, nitrogen-fixing cyanobacteria form extensive summer blooms in the Baltic Sea. Their ability to fix dissolved N₂ allows cyanobacteria to circumvent the general summer nitrogen limitation, while also generating a supply of novel bioavailable nitrogen for the food web. However, the fate of the nitrogen fixed by cyanobacteria remains unresolved, as does its importance for secondary production in the Baltic Sea. Here, we synthesize recent experimental and field studies providing strong empirical evidence that cyanobacterial nitrogen is efficiently assimilated and transferred in Baltic food webs via two major pathways: directly by grazing on fresh or decaying cyanobacteria and indirectly through the uptake by other phytoplankton and microbes of bioavailable nitrogen exuded from cyanobacterial cells. This information is an essential step toward guiding nutrient management to minimize noxious blooms without overly reducing secondary production, and ultimately most probably fish production in the Baltic Sea.     

Perspectives on utilising Community Land Trusts as a vehicle for affordable housing provision

With lack of affordable housing being clearly identified as a social and economic exclusion issue for most communities, innovative ways of addressing this deficiency should be considered. Increasingly local communities are engaging with the possibility of direct provision themselves and discussion around this notion has profound implications for community cohesion. One community-based solution gaining popular support within communities, and with government ministers, is the Community Land Trust mechanism. This involves control and ownership of land to help ensure affordable housing is built and remains affordable in perpetuity for the community. The language and difficulties with definition of terms, together with the complexity of engaging relevant stakeholders in a changing policy and legislative framework can be problematic. This may lead to apparent lack of consensus within communities on the way forward. Perceptions of local housing issues and ways to address them are sometimes vague, sometimes diverse but rarely apathetic. This paper includes data from two case studies in North East England, which are examined using interviews with key players, as a means of seeking some practical solutions.     

Predicting surfactant modified soil/water distribution coefficients using micellar HPLC

Soil water/distribution coefficients (Kd) have been measured for the partitioning of naphthalene, phenanthrene and pyrene between aqueous surfactant solutions and a clean soil. The surfactants used are ABA block copolymers constructed from ethylene oxide (the monomer used to synthesise the hydrophilic A blocks) and propylene oxide (used for the manufacture of the hydrophobic B block). Three of these surfactants comprising the same size propylene oxide block but different ethylene oxide/propylene oxide ratios were investigated. Increasing amounts of surfactant in the system result in a progressive decrease in the Kd values signifying an increasing tendency for the hydrophobic solutes to be dispersed in aqueous solution due to the action of the surfactant. More significantly for equal surfactant doses the most hydrophobic surfactant possessing the lowest ethylene oxide/propylene oxide ratio reduces Kd by the greatest amount whereas the most hydrophilic surfactant reduces Kd the least. Finally micellar HPLC using the above surfactants and hydrophobic solutes was undertaken. Interpolated capacity factors evaluated for particular surfactant doses correlated well with Kd values calculated for the same surfactant doses. The relationship between Kd and capacity was found to be log-linear and the correlation line could be fitted to the data obtained for all three surfactants. It is therefore concluded that micellar HPLC may be used for preliminary evaluations of the effectiveness of particular surfactants proposed for contaminated soils restoration schemes.