Speciation of heavy metals in electroplating industry sludge and wastewater residue using inductively coupled plasma

The speciation of metals in environmental samples is a critical factor in assessing the potential environmental impacts, before their disposal. The distribution and speciation of toxic heavy metals in plating wastewater residues and sludge was investigated for four samples using sequential extraction method. Tessier method was used to fractionate the metal content into exchangeable, acid extractable, reducible and oxidizable fractions. Residual and total metal contents were determined in aqua regia digest. The extracts were analysed for metals using inductively coupled plasma -atomic emission spectrometry. The bioavailable fraction (exchangeable and acid extractable fractions) is comprised less than the other forms. The oxidisable and reducible forms are dominants for all the four samples studied. The major metal constitute in the samples is iron, the wastewater residue contains (12.3 and 7.4 g/Kg respectively on dry basis) and the sludge contains (31.5 and 41.6 g /Kg) respectively. Cr concentration is higher in wastewater residue of second electroplating industry. The descending order of the average total metal contents for these four samples were Fe > Cr > Sn > Zn >Cu > Ni > Mn > Pb > Cd > Ag. Based on the average of absolute values for the four samples the highest bioavailability order of metals is Cr (39 %) in wastewater residues and Zn (32 %) in sludge samples. Metal recovery was good, with < 10 % difference between the total metal recovered through the extractant steps and the total metal determined using aqua regia extract.     

Wave trapping and flow around an irregular near circular island in a stratified sea

Wave trapping and induced flow around an island is examined. The exactly circular island solutions are reprised and the solutions extended, and shown to apply to a stratified sea. The homogeneous solutions are then used to deduce the wave trapping and flow around a near circular island. It turns out that the cotidal pattern for a perfectly circular island is relatively immune to variations in geometry and radially dependent depth variations. This helps explain the similarity in the behaviour of the tides around various islands (the Pribilof Islands near Alaska, Oahu in Hawaii, Cook Island off north west Australia, Bermuda off the eastern coast of the USA, and Bear Island in the Norwegian Sea). The dominant steady drift and its rate of decay off-shore is also calculated.     

SCAP at UCL

Mike Bode and Phil Charles present the minutes of the 11th meeting of the Standing Conference of Astronomy Professors on 3 July 2001.     

Platinum-group elements in the Boulder Bed,western Bushveld Complex,South Africa

Concentrations of platinum-group elements in samples from the Boulder Bed at five localities in the western Bushveld Complex range between 50 ppb and 70 ppm. Boulders thus have much more variable, and sometimes highly enriched, PGE contents relative to the other lithologies in the immediate foot-wall sequence of the Merensky Reef. The PGE enrichment can largely be modelled as a result of primary magmatic processes including collection of PGE by segregating sulphide melt and fractionation of mss. Other features of the Boulder Bed, such as the selvages of pure anorthosite and the chromitite stringers surrounding some of the boulders, bear evidence of recrystallisation. A model is proposed by which the Boulder Bed formed as a result of a combination of early and late magmatic processes. The PGEs were collected by magmatic sulphide melt which accumulated in a pyroxenite layer. The host rock to the pyroxenite was a thick package of norites which recrystallised in response to upward-migrating magmatic fluids. The fluids caused partial hydration melting of the norites adjacent to the pyroxenite, producing anorthosite. The boulders represent the broken-up remnants of the pyroxenite layer. The selvages of chromite and pure anorthosite around some of the boulders remain poorly understood, but may represent the latest recrystallisation event, in response to localised late-magmatic fluid overpressure upon cooling.     

Geography’s underworld: The military-industrial complex, mathematical modelling and the quantitative revolution

The Second World War marked an epochal change in the relation of geographers to war and the military. The military had long utilised the skills of geographers, but from World War II the relation changed at least in the United States, and the military began less drawing upon existing geographical knowledge than directing a new kind that was increasingly formal, instrumental, and model driven. With the growing importance of the computer, this trend continued even more strongly during the early Cold War period, and was further propelled by the interests of a new, collective assemblage, the military-industrial complex. A cyborg entity, the military-industrial complex enfolded diverse performances, ideas, inanimate objects, people and even academic disciplines into a larger composite, one product of which was a new regime for the production of knowledge. The purposes of the paper are to examine the process by which geography within the United Stated joined this cyborg entity, and the character of the disciplinary knowledge regime that eventuated. The argument is pursued by examining three individuals key to the new disciplinary regime: Waldo Tobler a pioneer of analytical cartography and later GIS whose first job was at RAND on a project to develop an early warning system for nuclear attack; William Garrison who spearheaded the use of economic modelling in studies of transportation that he carried out with his students at the University of Washington Seattle; and Arthur Strahler, a geologist at Columbia University, who through his links to the US Office of Naval Research, funded and directed a set of students who later entered physical geography utterly transforming it to meet the dictates of the new regime.     

Revisiting the red light district: Still neglected, immoral and marginal?

Twenty years ago, Ashworth et al. (1988) offered a distinctive and innovative interpretation of a neglected aspect of the urban scene: the red light district. Focusing on the location of female prostitution in a series of Western European cities, their paper suggested that the geographies of sex work are revealing of some of the ‘less obvious’ social and political processes that shape urban space. Here, we revisit Ashworth et al’s paper in the light of subsequent developments in the organisation of commercial sex as well as the study of sexuality and space. Noting important continuities as well as major shifts in the location of sex work, with a significant shift to off-street forms of sex working having occurred, this paper argues that some of the ideas in Ashworth et al’s paper remain highly pertinent, but others appear in need of updating. In particular, we stress the importance of focusing on men as both clients and workers within the sex industry, and flag up a number of connections that might be made with the emerging literatures on the geographies of sex itself. We hence conclude by considering Ashworth et al’s paper as an important early intervention in debates surrounding the relations of sexuality and space, albeit one in which questions of gender, embodiment, and sexual desire remained largely unexplored.     

Their grass is greener but ours is sweeter – Thoroughbred breeding and water management in the Upper Hunter region of New South Wales, Australia

The Upper Hunter region of New South Wales (NSW) around Scone is reputed to be the second most significant thoroughbred breeding region in the world after the Bluegrass region of Kentucky. This article identifies the importance and cultural constructions of grass, and hence water, in the thoroughbred breeding industry in this region. Thoroughbred stud managers attempt to produce environments attractive to potential horse purchasers and owners with mares to be mated. These environments are constructed from perceptions of how a thoroughbred stud should appear, and from the physical conditions of specific locations. One perception is that the grass should be green. There are differing opinions in the thoroughbred breeding industry about the nutritional value of irrigated grasses, the role of these grasses in horse development and the associated access to, cost of and efficacy of water used for this purpose. The paper concludes that effective water management in this industry is only possible if various cultures of nature are understood, where necessary challenged, and subsequently included in policy and planning.     

Latitude distributions and lifetimes of star-spots on G dwarfs in the α Persei cluster

We present a set of maximum-entropy reconstructions of the star-spot distributions on two rapidly rotating G dwarfs in the α Persei cluster, from spectra taken at the William Herschel Telescope on three nights in 1996 October and November. Since these stars are too faint for conventional Doppler imaging, which makes use of only one or a few lines, we take the large number of photospheric metal lines available in an echelle spectrum, and deconvolve them into a single, high signal-to-noise ratio profile. We show that this technique results in a typical multiplex gain of 22.5 in signal-to-noise ratio for a given spectrum, the equivalent of using a single line obtained on a 63-m telescope. The image reconstructions demonstrate that both these stars have cool high-latitude regions or polar crowns, and low-latitude features, in contradiction to the suggestion that only high-latitude spots should be present. Cross-correlation between image reconstructions of He 699, 31 days apart, reveals a lack of correlation between detailed small-scale structures. This places an upper limit for the lifetime of the observed features at less than one month. The Hα profiles are also found to exhibit absorption features indicating the presence of prominence clouds, at or below the corotation radius.