Efectos tóxicos de los metales sobre la actividad microbiana del sistema de lodos activos

[ES] En este trabajo se estudian los efectos tóxicos que los metales cadmio, cinc y cobre, tienen sobre la actividad microbiana del sistema de lodos activos. Los metales se adicionan al sistema diluidos en un agua residual sintética cuya DQO es de 520 mgO2/L y el ensayo se llevó a cabo durante un tiempo de 8 días. La toxicidad de estos metales se ha determinado a partir de la reducción que experimentan las medidas de actividad tales como la tasa específica de respiración y el porcentaje de células activas presente en el reactor. Los resultados experimentales obtenidos han permitido establecer la siguiente secuencia de toxicidad : Cd>Cu>Zn.Coello Oviedo, MD.; Sales Márquez, D.; Quiroga Alonso, JM. (2002). Efectos tóxicos de los metales sobre la actividad microbiana del sistema de lodos activos. Ingeniería del Agua. 9(3):309-317. https://doi.org/10.4995/ia.2002.2621SWORD30931793ALIBHAI, K.R.K., MEHROTRA, I. y FOSTERC.F. (1985). Heavy metal binding to digested sludge. Wat. Res. 19, 1483-1488.APHA; AWWA; WPCF (1989). Métodos Normalizados. Para el análisis de aguas potables y residuales. Editorial Díaz de Santos, S. A., Edición en español (1990).BAILEY, D.A; DORRELLJ.J. y ROBINSON K.S. (1970) The influence of trivalent chromium on the biological treatment of domestic sewage. Wat. Pollut. Control 69, 100-110.BATTISTONI P., FAVA G., y RUELLO, M.L. (1993). Heavy metal shock load in activated sludge uptake and toxic effects. Wat. Res. 27, 821-827.BROWN, M.J. y LESTER J. N. (1979) Metal removal in activated sludge: the role of bacterial extracellular polymers. Wat. Res. 13, 817-837.BROWN, M.J. y LESTER J. N. (1982). Role of bacterial extracellular polymers in metal uptake in pure bacterial culture and activated sludge-II. Wat. Res. 16, 1549-1560.CARDINALETTI, M.M ZITELLI, A., VOLPI GHIRARDINI, A. y AVEZZÚ, F (1990). Population dynamics of the microfauna in an activated sludge plant treating domestic and industrial effluents. Inquinamento 32,62-68.CHANG S. Y., HUANG, J.C. y LIU, Y.C. (1986). Effects of Cd (II) and Cu (II) on a biofilm system. J. Environ. Engng. 112, 94-104.DILEK, F.B. y YETIS. U. (1992). Effects of heavy metals on activated sludge process. Wat. Sci. Technol. 26, 801-813.GHOSH, M.M. y ZUGGER P.D. (1973). Toxic effects of mercury on the activated sludge process. J. Wat. Pollut. Control Fed. 45, 424-433.GRIEBE, T., SHAULE, G. y WUERTZ, S. (1997). Determination of microbial respiratory and redox activity in activated sludge. Journal of Industrial Microbiology & Biotechnology 19, 118-122.HARTZ, K.E., ZANE, A.T. y BHAGAT, S.K. (1985) The effect of selected metals and water hardness on the oxygen uptake of activated sludge. J. Wat. Polut. Control Fed. 57, 942-947.KLAPWIJK, A., DRENT, J. y STEENVOORDEN VAN J.H.A.M.(1974) A modified procedure for the TTC-dehydrogenase test in activated-sludge. Water Res. 8, 121-125.KUNZ, R.G., GIANELLI, J.F. y STENSEL, H.D. (1976) Vanadium removal from industrial waste waters. J. Wat. Pollut. Control Fed. 48, 762-770.MADONI, P. (1994). A sludge biotic index (SBI) for the evaluation of the biological performance of activated sludge plants based on the microfauna analysis. Water Res.28 (1): 67-75.MADONI, P, DAVOLI, D., GORBI, G. y VESCOVI, L. (1996). Toxic effect of heavy metals on the activated sludge protozoan community. Wat. Res 30 (1) 135-141.NELSON, P. O., CHUNG, A.K. y HUDSON, M.C. (1981). Factors affecting the fate of heavy metals in the activated sludge process. J. Wat. Pollut. Control Fed. 48, 1940-1947.NEUFELD, R.D. (1976). Heavy metals induced defloculation of activated sludge. J. Wat. Pollut Control Fec. 48, 1940-1947.OLIVER, B. G. y COSGROVE, E.G. (1974). The efficiency of heavy metal removal by a conventional activated sludge treatment plant. Wat. Res. 8, 869-874.RUDD, T., STERRITT, R.M. y LESTER, J.N. (1983). Stability constants and complexation capacities of complexes formed between heavy metals and extracellular polymers from activated sludge. J. Chem. Tecnol. Biotecnol. 33a, 374-380.RUDD, T., STERRITT, R.M. y LESTER, J.N. (1984). Formation and conventional stability constants of complexes formed between heavy metals and bacterial extacellular polymers. Wat. Res. 18, 379-384.SCHAULE, G; FLEMMING, H-C; RIDGWAY, H.F. (1993). Use of 5-Cyano-2,3-Ditolyl Tetrazolium Chloride for Quantifying Planktonic and Sessile Respiring Bacteria in Drinking Water. Applied and Environmental Microbiology 11 (59): 3850-3857.SHUTTLEWORTHK.L. y UNZ, R.F. (1988). Growth of filamentous bacteria in the presence of heavy metals. Wat. Sci. Technol. 20, 485-487.WHEATLAND, A. B., GLEDHIL, C. y O ́GORMAN, J.V. (1975). Developments in the treatment of metal-bearing effluents. Chem. Ind. 32, 632-638

Narratives of ethnic identity among practitioners in community settings in the northeast of England

The increasing ethnic diversity of the UK has been mirrored by growing public awareness of multicultural issues, alongside developments in academic and government thinking. This paper explores the contested meanings around ethnic identity/ies in community settings, drawing on semi-structured interviews with staff from Children’s Centres and allied agencies conducted for a research project that examined the relationship between identity and the participation of parents/carers in services in northeast England. The research found that respondents were unclear about, especially, white ethnic identities, and commonly referred to other social categorizations, such as age, nationality, and circumstances such as mobility, when discussing service users. While in some cases this may have reflected legitimate attempts to resist overethnicizing non-ethnic phenomena, such constructions coexisted with assumptions about ethnic difference and how it might translate into service needs. These findings raise important considerations for policy and practice

Liquid racism and the Danish Prophet Muhammad cartoons

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2010 The Author.This article examines reactions to the October 2005 publication of the Prophet Muhammad cartoons in the Danish newspaper Jyllands-Posten. It does so by using the concept of ‘liquid racism’. While the controversy arose because it is considered blasphemous by many Muslims to create images of the Prophet Muhammad, the article argues that the meaning of the cartoons is multidimensional, that their analysis is significantly more complex than most commentators acknowledge, and that this complexity can best be addressed via the concept of liquid racism. The article examines the liquidity of the cartoons in relation to four readings. These see the cartoons as: (1) a criticism of Islamic fundamentalism; (2) blasphemous images; (3) Islamophobic and racist; and (4) satire and a defence of freedom of speech. Finally, the relationship between postmodernity and the rise of fundamentalism is discussed because the cartoons, reactions to them, and Islamic fundamentalism, all contain an important postmodern dimension.ESR

Engaging with History after Macpherson

The Race Relations Amendment Act (2000) identifies a key role for education, and more specifically history, in promoting ‘race equality’ in Britain. In this article Ian Grosvenor and Kevin Myers consider the extent of young people’s current engagement with the history of ‘diversity, change and immigration’ which underpins the commitment to ‘race equality’. Finding that in many of Britain’s schools and universities a singular and exclusionary version of history continues to dominate the curriculum, they go on to consider the reasons for the neglect of multiculturalism. The authors identify the development of an aggressive national identity that depends on the past for its legitimacy and argue that this sense of the past is an important obstacle to future progress

Review debate: we need human rights not nationalism 'lite': globalization and British solidarity

The article explores the relationship of multiculturalism to social solidarity. The multicultural nature of Britain is accepted as a welcome reality but certain problems in relation to the development of multiculturalism in Britain are acknowledged. Various approaches to buttress or replace multiculturalism are reviewed. These are: a strengthened and/or reconstituted nationalism (`Britishness'); human rights; and social equality. The issue of citizenship recurs throughout. It is argued that a combined emphasis on human rights and greater social equality offer a better basis than nationalism for strengthening solidarity in Britain, especially in the longer term. Sociological theory offers a fruitful if strangely neglected starting point for understanding social solidarity. I draw critically on Durkheim and Marx to obtain some objective perspective on this controversial matter. Copyright 2007 SAGE Publications. All rights reserved. Not for commercial use or unauthorized distribution

The Transformation of Citizenship in Complex Societies

The main purpose of this paper is to propose a theoretical framework for understanding the transformation of citizenship in complex societies. To this end, the paper is divided into six sections. The first section elucidates the main reasons for the renaissance of the concept of citizenship in the contemporary social sciences. The second section argues that a comprehensive sociological theory of citizenship needs to account for the importance of four dimensions: the content, the type, the conditions, and the arrangements of citizenship. The third section suggests that in order to understand the sociological significance of T.H. Marshall’s account of legal, political, and social rights we need to explore the particular historical contexts in which citizenship rights became ideologically and institutionally relevant. The fourth section offers some critical reflections on the main shortcomings of the Marshallian approach to citizenship. The fifth section draws an analogy between the transformation of social movements and the transformation of citizenship. The sixth section sheds light on the fact that contemporary citizenship studies are confronted with a curious paradox: the differentiation of citizenship has led to both the relativistic impoverishment and the pluralistic enrichment of contemporary accounts of ‘the social’ and ‘the political’.The paper concludes by arguing that, under conditions of late modernity, the state’s capacity to gain political legitimacy increasingly depends on its ability to confront the normative challenges posed by the ubiquity of societal complexity

Prion protein-specific antibodies that detect multiple TSE agents with high sensitivity

This paper describes the generation, characterisation and potential applications of a panel of novel anti-prion protein monoclonal antibodies (mAbs). The mAbs were generated by immunising PRNP null mice, using a variety of regimes, with a truncated form of recombinant ovine prion protein spanning residues 94–233. Epitopes of specific antibodies were mapped using solid-phase Pepscan analysis and clustered to four distinct regions within the PrP molecule. We have demonstrated the utility of these antibodies by use of Western blotting and immunohistochemistry in tissues from a range of different species affected by transmissible spongiform encephalopathy (TSE). In comparative tests against extensively-used and widely-published, commercially available antibodies, similar or improved results can be obtained using these new mAbs, specifically in terms of sensitivity of detection. Since many of these antibodies recognise native PrPC, they could also be applied to a broad range of immunoassays such as flow cytometry, DELFIA analysis or immunoprecipitation. We are using these reagents to increase our understanding of TSE pathogenesis and for use in potential diagnostic screening assays

Idi Amin's Uganda Retold

A programme on Idi Amin's Uganda and how he played populist, nativists who had turned against Asians, partly because of racism they had suffered from white colonialists and Asian settlers