Key barriers to community cohesion: views from residents of 20 London deprived neighbourhoods

The notion of community has been central to the political project of renewal of New Labour in the UK. The paper explores how the discourses of community are framed within New Labour and discusses these in the light of the results from research which focuses on how people within urban deprived areas construct their community. It draws upon the results of one part of a larger research project (the ‘Well London’ programme) which aimed to capture the views of residents from 20 disadvantaged neighbourhoods throughout London using an innovative qualitative method known as the ‘World Café’. Our results show the centrality of young people to the development of cohesive communities, the importance of building informal relationships between residents alongside encouraging greater participation to policy making, and the need to see these places as fragile and temporary locations but with considerable social strengths. Government policies are only partially addressing these issues. They pay greater attention to formally encouraging citizens to become more involved in policy making, largely ignore the contribution young people could make to the community cohesion agenda, and weakly define the shared norms and values that are crucial in building cohesive communities. Thus, the conclusion is that whilst an emphasis of the government on ‘community’ is to be welcome, more needs to be done in terms of considering the ‘voices’ of the community as well as enabling communities to determine and act upon their priorities.     

Geo-feasibility of in situ sediment capping in a Great Lakes urban estuary: a sediment budget assessment

Presque Isle Bay is one of 40 remaining environmental areas of concern (AoCs) on the North American Great Lakes that have one or more water, habitat, or sediment quality impairments as defined by the International Joint Commission. In situ natural capping using sediment from to-be-remediated watersheds and other potential sources is being considered as the most feasible means of remediating an existing contaminated sediment problem at this site. A multi-decade (∼40 year) sediment budget shows that, when localized anthropogenic effects (dredging, reclamation) are discounted, the bay net-accumulated sediment over time. Sediment was supplied from three major sources: bank erosion and bluff retreat (41%), streams (25%), and the Lake Erie littoral system (20%). The non-stream sources supply environmentally clean materials from ancient beach and glacio-lacustrine deposits along the shoreline, and from the modern littoral system. Organic and metallic contaminants supplied primarily by streams and run-off remain a remediation challenge for the AoC. Geologically, natural capping of contaminants over the next several decades is a viable solution for most of the bay. The mechanism may not work effectively in all areas because approximately 25% of the bay floor is moderately net-erosional while several localized areas accumulate sediments very slowly at decadal timescales.     

Hydrogeology of northern Sierra de Chiapas,Mexico: a conceptual model based on a geochemical characterization of sulfide-rich karst brackish springs

Conspicuous sulfide-rich karst springs flow from Cretaceous carbonates in northern Sierra de Chiapas, Mexico. This is a geologically complex, tropical karst area. The physical, geologic, hydrologic and chemical attributes of these springs were determined and integrated into a conceptual hydrogeologic model. A meteoric source and a recharge elevation below 1,500 m are estimated from the spring-water isotopic signature regardless of their chemical composition. Brackish spring water flows at a maximum depth of 2,000 m, as inferred from similar chemical attributes to the produced water from a nearby oil well. Oil reservoirs may be found at depths below 2,000 m. Three subsurface environments or aquifers are identified based on the B, Li⁺, K⁺ and SiO₂ concentrations, spring water temperatures, and CO₂ pressures. There is mixing between these aquifers. The aquifer designated Local is shallow and contains potable water vulnerable to pollution. The aquifer named Northern receives some brackish produced water. The composition of the Southern aquifer is influenced by halite dissolution enhanced at fault detachment surfaces. Epigenic speleogenesis is associated with the Local springs. In contrast, hypogenic speleogenesis is associated with the brackish sulfidic springs from the Northern and the Southern environments.     

Natural building stone composed of light-transmissive minerals: impacts on thermal gradients,weathering and microbial colonization. A preliminary study,tentative interpretations,and future directions

A number of modern buildings employing claddings of granites or marbles have experienced bowing of the rock panels together with weathering of the material. Theoretical and field-based data analysis and laboratory experimentation have assumed that heat exchange resulting from incoming solar radiation is at the material surface. However, a number of recent experiments have clearly shown that some lithologies, including both marble and granite, comprise a number of light-transmissive minerals that significantly change the thermal responses in the outer few millimetres of the rock. Further, this translucence will create mineral-to-mineral stresses where light-transmissive minerals are in contact with opaque ones. The whole is further exacerbated by differences in thermal coefficients of expansion and conductivity which themselves may depend on the mineral axis; surface modifiers such as paints further complicate the situation. The degree of light penetration, based on field measurements, can be significant and can facilitate rapid changes in temperature (ΔT/Δt > 2°C min⁻¹) at depth within the rock thereby increasing the sub-surface stresses. The amount of light penetration for any given mineral will be dependent upon material slope, the latitude, season, and albedo. Albedo is identified as a complex variable, changing as a function of the angle of the sun to the particular surface; polished surfaces, as often with cladding, will further influence this. Data analysis suggests that, in the Northern hemisphere, south of the polar circle, the summer may not be the time of the largest heat loading on the southern aspect and that larger loadings, coupled with lower air temperatures, occur early and late in the year. This seasonal impact has great potential for thermal stresses on the southern aspect. The presence of light-transmissive minerals also allows sub-surface biotic colonization and results in weathering. Overall, where light transmissive minerals/lithologies occur the thermal responses are highly complex and in need of more rigorous consideration.     

The Influence of Salinity on the Uptake, Distribution, and Excretion of Metals by the Smooth Cordgrass, Spartina alterniflora (Loisel.), Grown in Sediment Contaminated by Multiple Metals

The effect of salinity on the concentration of metals in Spartina alterniflora tissues and excreted salts and the distribution of metals between these compartments was tested in a greenhouse experiment. S. alterniflora stems were planted in pots of dredge sediment that was amended with a suite of six metals (Cd, Cr, Cu, Ni, Pb, and Zn). The overlying water of individual pots was maintained at treatment salinities of 0, 15, or 30 practical salinity units. The proportion of total metal distributed to the tissues and excreted salt of S. alterniflora was not significantly influenced by salinity for any of the metals. The concentration of Pb in root and leaf tissues and in excreted salt was influenced by salinity, as was the concentration of Zn in root tissue and excreted salt. Contrary to expectations, the concentration of Pb and Zn in excreted salts decreased as salinity increased. Although the influence of salinity on the concentration of Pb and Zn in S. alterniflora tissue has not been previously reported, the influence of salinity on the tissue concentrations of Pb agrees with previous research on dicots.     

Particulate aluminium in boreal streams: Towards a better understanding of its sources and influence on dissolved aluminium speciation

The adverse impacts of the inorganic labile monomeric Al (Al_i) fraction on aquatic organisms have meant that Al (Al_tot) determination and even speciation has become a routine part of environmental monitoring and assessment. However, if samples are not filtered prior to analysis then particulate Al (Al_tot(p)) could influence the determination of Al_tot, and therefore the determination of the more toxicologically important (Al_i), both when it is measured analytically or modelled from Al_tot. This paper shows that the Al/DOC ratio in unfiltered samples can identify the Al_tot(p) fraction, and thus improve the speciation of Al_i. These findings are based on data from a study in a 67 km² catchment in northern Sweden during the snowmelt-driven spring flood of two consecutive years. Filtered and unfiltered samples were studied to determine the spatial and temporal patterns in Al_tot(p). The concentrations of Al_tot(p) were greatest in larger downstream sites where significant silt deposits are located. The sites with no silt in their drainage area showed a mean difference between filtered (Al_tot(f)) and unfiltered (Al_tot(uf)) samples of 6%, while sites with silt deposits had a mean difference of 65%. The difference between filtered and unfiltered samples was greatest at peak flow. Spikes in Al_tot(p) did not behave consistently during fractionation with a cation exchange column, resulting in increases in either measured Al_i(f) or non-labile monomeric Al (Al_o(f)). Al_tot(p) spikes were associated with sharp increases in the Al:DOC ratio. The baseflow Al:DOC ratio could be used to model filtered Al_tot from DOC with a Spearman rho of 0.75.     

Spatial variations in chemical compositions along Langtang–Narayani river system in central Nepal

Surface water samples were collected from Langtang Lirung glacier outlet point to the Narayani river system in central Nepal in order to investigate the role of elevation in the variation of chemistry along the drainage networks. The chemistry of Langtang–Narayani river system was dominated by sulfide oxidation coupled with carbonate dissolution and weathering of silicate minerals. Calcium and magnesium concentrations were relatively higher than other cations and the sum of both species strongly correlated with alkalinity, supporting the dissolution of carbonate and dolomite as the dominant source for these ions. Aluminosilicate minerals primarily as albite and anorthite appeared as dominant silicate minerals within the drainage basin. Bisiallitization was the dominant type of weathering within the entire drainage system. Hydrogen ion concentration was lower in the low elevation sites than in high elevation sites reflecting the more consumption of carbon dioxide in the low elevation sites due to enhanced chemical weathering rates. Furthermore, major solutes like sum of base cations, silicon as well as alkalinity increased in concentration in the lower elevation sites. All regulating factors appeared to be directly related to elevation and hence elevation appeared to be the prime factor for the variation in chemical species along the Langtang–Narayani river system. Toshiyuki Masuzawa: deceased.     

Pyrolysis of modern wetland sediment: extracting climate records from fens in the Uinta Mountains and Fish Lake Plateau,Utah, USA

Rock‐Eval pyrolysis provides a quick, relatively inexpensive means of characterizing organic‐rich strata, and has been used for decades to understand global petroleum systems. Although designed to characterize ancient kerogens, pyrolysis is increasingly being used to understand Holocene systems as well. The ability of this technique to distinguish between types of preserved organic matter is useful in characterizing climatic evolution, particularly in systems sensitive to climatic fluctuation such as isolated fens and bogs. Cores collected from the Tokewanna and Garden Basin Cattail fens in central/eastern Utah exhibit variability of organic source, with the mixture of terrestrial and algal sources varying through time, as shown through the hydrogen index (HI) and oxygen index pyrolysis parameters. A sediment core was collected at each fen, and 176 samples were taken from the cores at 6‐cm intervals. Total organic carbon (TOC) for all samples ranges from 1.3 to 44.2%, with an average of 18.2% TOC. Samples range from 84 to 687 HI, equivalent to Type I (lacustrine algal) to Type III (terrestrial) organic material (OM). Variability in HI response represents mixing of the two OM sources, and the relative amount of aqueous organic input can be estimated through time based on age‐calibrated HI curves at the two sites. The balance of organic input serves as an accurate, high‐resolution proxy for climate, and calibration with palynological data near both sites confirms patterns shown by pyrolysis, showing the utility of this method in quickly, affordably and accurately characterizing Holocene sediments for use in understanding palaeoclimate.     

Long-term temporal trends (1992-2008) of imposex status associated with organotin contamination in the dogwhelk Nucella lapillus along the Icelandic coast

Using the dogwhelk Nucella lapillus as a biomonitor, we evaluated the organotin contamination along the Icelandic coast over nearly two decades. In 2008, adult dogwhelks collected from 30 locations were examined for imposex status. In 2009, tissue concentrations of six organotin species in dogwhelks from 16 of the 30 locations were analysed using gas chromatography-mass spectrometry. Tributyltin was the most predominant residue ranging from 2.07 to 70.38 μg kg(-1) dw, while triphenyltin was also detected at concentrations up to 22.79 μg kg(-1) dw. Higher total organotin concentrations and imposex indices were observed at locations near large harbours (Reykjavík and Hafnarfj?reur). By comparing the current imposex results with those of previous surveys (1992-2003), we found that recovery was slow near the large harbours, but more apparent near the smaller harbours. We also observed a notable increase in imposex at several northwest sites implying incessant input of organotins.     

Rock thermal data at the grain scale: applicability to granular disintegration in cold environments

Consideration of the mechanisms associated with the granular disintegration of rock has been limited by available data. In most instances, both the size of the transducer and the nature of the study have negated any applicability of the resulting data to the understanding of grain‐to‐grain separation within rock. The application of microthermocouples (≤0·15 mm diameter) and high‐frequency logging (20 s intervals) at a taffoni site on southern Alexander Island and from a rock outcrop on Adelaide Island (Antarctica) provide new data pertaining to the thermal conditions, at the grain scale, of the rock surface. The results show that thermal changes (ΔT/t) can be very high, with values of 22 °C min^?1 being recorded. Although available data indicate that there can be differences in frequency and magnitude of ?uctuations as a function of aspect, all aspects experienced some large magnitude (≥2 °C min^?1) ?uctuations. Further, in many instances, large thermal changes in more than one direction could occur within 1 min or in subsequent minutes. These data suggest that the surface grains experience rapidly changing stress ?elds that may, with time, effect fatigue at the grain boundaries; albedo differences between grains and the resulting thermal variations are thought to exacerbate this. The available data failed to show any indication of water freezing (an exotherm) and thus it is suggested that microgelivation may not play as large a role in granular breakdown as is often postulated for cold regions, and that in this dry, Antarctic region thermal stress may play a signi?cant role. Copyright © 2003 John Wiley & Sons, Ltd.