Arsenic contamination in groundwater : some analytical considerations

For countries such as Bangladesh with a significant groundwater arsenic problem, there is an urgent need for the arsenic-contaminated wells to be identified as soon as possible and for appropriate action to be taken. This will involve the testing of a large number of wells, potentially up to 11 million in Bangladesh alone. Field-test kits offer the only practical way forward in the timescale required. The classic field method for detecting arsenic (the ‘Gutzeit’ method) is based on the reaction of arsine gas with mercuric bromide and remains the best practical approach. It can in principle achieve a detection limit of about 10 μg l−1 by visual comparison of the coloured stain against a colour calibration chart. A more objective result can be achieved when the colour is measured by an electronic instrument. Attention has to be paid to interferences mainly from hydrogen sulfide. Due to analytical errors, both from the field-test kits and from laboratory analysis, some misclassification of wells is inevitable, even under ideal conditions. The extent of misclassification depends on the magnitude of the errors of analysis and the frequency distribution of arsenic observed, but is in principle predictable before an extensive survey is undertaken. For a country with an arsenic distribution similar to that of Bangladesh, providing care is taken to avoid sources of bias during testing, modern field-test kits should be able to reduce this misclassification to under 5% overall

Heat in the Heartland: Climate Change and Economic Risk in the Midwest

This report offers a first step toward defining the range of potential economic consequences to the Midwest if we continue on our current greenhouse gas emissions pathway. The research combines state-of-the-art climate science projections through the year 2100 (and beyond in some cases) with empirically-derived estimates of the impact of projected changes in temperature and precipitation on the Midwest economy. The authors analyze not only those outcomes most likely to occur, but also lower-probability, higher-cost climate futures. These are the "tail risks," most often expressed here as the 1-in-20 chance something will occur. Unlike any other study to date, this report looks at climate impacts at a very geographically granular level, in some cases providing county-level results

Conflating Student and Professional Identities: fostering development of professional identity in first year architecture

Students in architecture undergo a dual transition when they commence tertiary study, taking on a student identity but also assuming their professional identity as a creative practitioner. The peculiarities of pedagogical frameworks in these disciplines require tailored support mechanisms to ensure student success. Students undertake a series of inquiry and practice based formative assessment tasks in the design studio, which build to the final summative assessment the design jury and critique. As the predominant mode of studio assessment around the world, this is a daunting event for students. Facilitating students to successfully develop their professional identity from the commencement of first year, and building resilience into their learning experiences, can transform this event into a genuine learning experience. This paper outlines the interventions for transition students in the School of Architecture at University of Technology Sydney

Common Core State Standards and Text Complexity: An Invitation to Learn Language in STEM Disciplines using a Range of Quality Literature

The Common Core State Standards (CCSS) emphasize literacy learning within history/social studies, science, and technical subjects making students’ reading, writing, and language development every teacher’s concern, regardless of the discipline being taught. Books related to science, technology, engineering, and mathematics (STEM) can enhance students’ knowledge of key terms and concepts as they are revealed in authentic contexts. Students who often struggle harder to understand advanced vocabulary embedded in stories or in difficult, yet interestingly presented nonfiction gain an increased print vocabulary by reading quality STEM-aligned literature selections that exhibit the characteristics of complexity and richness of language advocated by CCSS. Effectively pre-teaching vocabulary and scaffolding students’ use of self-regulation strategies to discover word meanings will increase comprehension and content literacy as well as content learning

Arsenic in groundwater and the environment

Awareness of the problems associated with arsenic in drinking water and the environment has grown significantly over the last two decades or so and today an enormous literature exists documenting its occurrence, behaviour and impacts in many places across the globe. The mobilisation of arsenic in the environment occurs through a complex combination of natural biogeochemical reactions and human interactions. Most recognised problems are generated by mobilisation and transport under natural conditions, but mobilisation has also been caused, or exacerbated, by mining, fossil-fuel combustion and use of synthetic arsenical compounds (pesticides, herbicides, crop desiccants and arsenic-based additives in livestock feed). Arsenical pesticides and herbicides have been used much less over the last few decades, and more recent restrictions have been imposed on the use of arsenic in wood preservation (e.g. European Communities’ Directive 2003/2/EC), but the legacy of such sources may still pose a localised threat to the environment

Molybdenum in natural waters: a review of occurrence, distributions and controls

Molybdenum is an essential trace element for human, animal and plant health and has played an important part in the evolution of life on earth. Nonetheless, exposure to the element can be harmful and although the evidence for symptoms in humans is sparse, it has been linked with a number of health conditions in animal models. Molybdenum is present in trace quantities (1–10 mg/kg) in most rocks and soils and at concentrations less than, and often orders of magnitude less than, 10 μg/L in most freshwaters. It is the most abundant transition metal in open seawater (10 μg Mo/L) owing to the dominance, and low chemical reactivity, of the molybdate ion (MoO42-). The 2011 WHO Guidelines for Drinking-Water Quality (fourth edition) advised a health-based value of 70 μg/L for Mo but this is no longer promulgated as a formal guideline value as WHO consider such concentrations to be rarely found in drinking water. This is indeed usually the case, but there are instances where currently-used drinking waters do exceed 70 μg Mo/L. We therefore recommend more routine measurement of Mo in water, at least on a reconnaissance scale, in order to improve knowledge on occurrence in water used for potable supply. Where multi-element analytical procedures are already used (e.g. ICP-MS), the marginal cost of adding Mo to the list of elements to be analysed should not be great. We have reviewed nine areas in the world where high concentrations of Mo in freshwater, and in some cases drinking water, have been found: Argentina, Jordan, Qatar, Ethiopia, UK, USA (three) and Chile. These represent a range of geochemical environments. A common theme of the high-Mo occurrences is (i) oxic, alkaline conditions where, as for seawater, the Mo occurs as the stable molybdate ion; groundwater in oxic, alkaline conditions within volcanogenic sediments can have exceptionally high Mo concentrations (up to hundreds of μg/L) where felsic volcanic ash is present; (ii) anoxic, non-sulphidic waters where Mo can be released to solution by reductive dissolution of Mn and Fe oxides or by release from degradation of organic matter, notably within high-Mo organic-rich muds, black shales or oil shales; or (iii) surface waters or groundwater impacted by metal sulphide mining and/or mineralisation, in particular occurrences of porphyry deposits. Under such conditions, Mo concentrations can reach several tens to several hundreds of μg/L and while not all are otherwise suitable for drinking water, some are. Much of the basic geochemistry of Mo in oxic natural environments is now quite well understood. Critically, its behaviour is redox-sensitive like its near neighbours in the Periodic Table, W and V. At the near-neutral pH values characteristic of most natural waters, Mo is rather weakly sorbed and formation of Mo minerals is either not indicated or is extremely slow. Molybdenum becomes less mobile when converted to thiomolybdates under the strongly reducing conditions found in some present-day ocean basins (e.g. the Black Sea), fjords, stratified lakes and confined aquifers. This leads to concentrations of around 100 mg Mo/kg or more in black shales and other organic-rich mudstones. However, despite the many studies of these water bodies and the importance of Mo as a palaeoredox indicator, the mechanism of the highly-efficient and diagnostic scavenging of Mo in euxinic (H2S-rich) waters remains uncertain. Possibilities include the formation of an as yet unidentified Mo-Fe-S mineral or solid solution, or the scavenging by some pre-existing solid such as a sulphide or oxide mineral, or organic matter. The possible role of dispersed and reduced natural organic matter has become more prominent in recent years but this has proven difficult to quantify and the mechanism of binding is poorly understood. Molybdenum isotope studies now play an important role in constraining reaction pathways. At a more fundamental level, there is a lack of up-to-date thermodynamic and kinetic data for many of the reactions of importance for Mo in the natural environment and this limits the ability of current geochemical models to predict its fate and transport. This is particularly true for the strongly reducing conditions where Mo partitions to the solid phase, leading to the formation of the Mo-rich shales. Even the existence of reduced aqueous Mo species (e.g. in the Mo(V) and Mo(III) oxidation states) in natural waters is uncertain. These uncertainties will only be resolved with focused laboratory experiments using the benefits of modern instrumentation, combined where necessary with supporting molecular dynamics calculations. The mobility of Mo in aqueous systems has to date received far more attention in the marine than the freshwater setting. The value of Mo speciation as an indicator of redox conditions and of stable-isotopic variations as a tracer, can have more value in the arena of environment and health, and studies of the element's mobility in aqueous systems can be useful for themes varying from radioactive waste disposal, sustainability of unconventional hydrocarbon exploitation and wider surficial pollution

Phytoestrogens in Human Pregnancy

Background. The hormonal milieu associated with pregnancy has become a focus of interest owing to potential links with the developmental origins of health and disease. Phytoestrogens are hormonally active plant-derived chemicals that may have an impact on human reproductive processes. However, developmental exposure to phytoestrogens has not been well characterized and thus our objective was to quantify phytoestrogen exposure during pregnancy and lactation. Methods. Women in the second trimester of pregnancy entered the study during counseling for prenatal genetic information. Women who had an indication for a genetic amniocentesis on the basis of late maternal age were approached for inclusion. They completed an environmental questionnaire; a sample of amniotic fluid was collected for karyotype, blood was collected from women during pregnancy and at birth, from the umbilical cord and breast milk. Samples were tested for the presence of daidzein and genistein by GC Mass Spectroscopy. Findings. Phytoestrogens are commonly found in pregnant women's serum and amniotic fluid during pregnancy. There is a sex difference in the concentrations with higher levels in amniotic fluid containing female fetuses. This difference was not present in maternal serum. Soy ingestion increases amniotic fluid phytoestrogen concentrations in female and male fetuses. The presence and concentrations of phytoestrogens did not differ in relation to common pregnancy complications or preexisting infertility

Spatial Reading: Digital Literary Maps of the Icelandic Outlaw Sagas

Digital humanities scholarship contributes to current conversations on literature in many forms, especially in its recontextualizing of what it means to read. By integrating visual, spatial, and quantitative forms of knowledge alongside the practice of text-based hermeneutics, digital techniques expand the possibilities of interpreting texts, particularly with the emergence of widely available geospatial and data visualization tools. This article outlines and reflects on a methodology for producing geospatial and data visualizations of place names in the Icelandic outlaw sagas, and discusses how the results corroborate existing research and also facilitate critical methods of ‘reading’ these texts spatially. While articulating the saga-specific findings of the visualizations, this article also contextualizes the conceptual work of digital literary mapping as a method that is particularly insightful as we determine the role and validity of digital techniques, especially for interdisciplinary and historically-situated work

The Shape of Knowledge: The Postwar American Poet\u27s Library, with Diane di Prima and Charles Olson

On the shelves of any collection of books, or what we might deem “a library,” is material evidence that generates multiple vectors of meaning. After D. F. McKenzie\u27s “sociology of the text,” our ability to read books requires that we not just know their contents, but understand the networks in which they are built, distributed, interpreted, and used. In this capacity, books are a prime way of answering a political and epistemological question: how does knowledge take material form? And how is this process politically shaped at different points in time, by the types of knowledge that are privileged, siloed, distributed, or silenced? This dissertation asks this question through the eyes of two key knowledge-seeking poets in post-1945 American poetry: Diane di Prima and Charles Olson. Writing during the height of the Cold War, and later Vietnam, Olson and di Prima were intimately familiar with the restrictive approach applied to knowledge in the mid-twentieth century (the former investigated, the latter arrested, by the FBI). Since both of their poetic practices involved extensive historical research, covering Mayan glyphs, pre-Christian Western ritual, the history of America, and alchemy, Olson and di Prima understood the precarity of what knowledge takes material, discoverable form—if it ever does. Writing alongside Amiri Baraka, Muriel Rukeyser, Ed Sanders, and other poets in this era (whose Blues People, Willard Gibbs, and Investigative Poetry demonstrate intuitive research and recovery practices), Olson and di Prima make vivid the truth that building and keeping books is a political act. Not just the idea of knowledge—newly “disembodied” in Cold War America, thanks to models of information theory—but its specific material conditions are essential to Olson and di Prima. Both poets invested heavily in form as a key concept in their poetics: Olson, through the groundbreaking “Projective Verse,” and Diane di Prima, with her dedication to representing embodied experience with its mysteries undiminished. Both Olson and di Prima are prolific book collectors, and at times cataloguers, impromptu archivists, and assemblers of their own extensive libraries. Their devotion to knowledge-seeking as an embodied practice that happens in libraries, archives, museums, and cities—beyond the narrow realms of academic-meaning making that they both rejected—shows how poets, working outside of formal institutions, structured the very shape of knowledge as they collected it in post-1945 America. Among numerous archival documents and collections, two important non-institutional resources address these critical features of Olson and di Prima’s work. The first, the Maud/Olson Library in Gloucester, Massachusetts, contains a copy of every book Olson was ever thought to have read, collected by scholar Ralph Maud with annotated bookplates. The second is Diane di Prima’s “occult library,” a collection of books that dates back to the 1960s that she envisions as a specific act of archival preservation and as a working resource. Alongside the context of these libraries, di Prima’s understudied role as a printer and publisher, especially around the era of Revolutionary Letters in the 1960s and 1970s, offers greater insight into how di Prima in particular addresses the importance of securing knowledge in material form by taking matters into her own hands. Together, these objects of study offer a perspective on libraries, archives, and books that is fully articulated by poets—a key perspective against the larger backdrop of institutions, professional organizations, and dealers that now shape the world of special collections. By exploring these specific case studies—the Maud/Olson Library, Diane di Prima\u27s occult library, and Diane di Prima’s work as a publisher in her work Revolutionary Letters—this dissertation establishes three main arguments. Firstly, libraries that belong to poets are significant archival and conceptual units, which require specific institutional and scholarly approaches in order to be legible and indeed preserved. Secondly, that understanding these libraries as projects of how poets structure knowledge in postwar America offers us new insights into the question of the “postmodern,” or information overload from an archival perspective. And thirdly, that Diane di Prima\u27s work warrants far more extensive critical study for her work at the intersection of multiple identities that make knowledge material: publisher, book collector, and indeed, alchemist. For the evidence of these claims, I turn to the books themselves