Quantifying constraints imposed by calcium and iron on bacterial reduction of uranium(VI)

Uranium is a redox active contaminant of concern to both human health and ecological preservation. In anaerobic soils and sediments, the more mobile, oxidized form of uranium (UO(2)(2+) and associated species) may be reduced by dissimilatory metal-reducing bacteria. Despite rapid reduction in controlled, experimental systems, various factors within soils or sediments may limit biological reduction of U(VI), inclusive of competing electron acceptors and alterations in uranyl speciation. Here we elucidate the impact of U(VI) speciation on the extent and rate of reduction, and we examine the impact of Fe(III) (hydr)oxides (ferrihydrite, goethite, and hematite) varying in free energies of formation. Observed pseudo first-order rate coefficients for U(VI) reduction vary from 12 +/- 0.60 x 10(-3) h(-1) (0 mM Ca in the presence of goethite) to 2.0 +/- 0.10 x 10(-3) h(-1) (0.8 mM Ca in the presence of hematite). Nevertheless, dissolved Ca (at concentrations from 0.2 to 0.8 mM) decreases the extent of U(VI) reduction by approximately 25% after 528 h relative to rates without Ca present. Imparting an important criterion on uranium reduction, goethite and hematite decrease the dissolved concentration of calcium through adsorption and thus tend to diminish the effect of calcium on uranium reduction. Ferrihydrite, in contrast, acts as a competitive electron acceptor and thus, like Ca, decreases uranium reduction. However, while ferrihydrite decreases U(VI) in solutions without Ca, with increasing Ca concentrations U(VI) reduction is enhanced in the presence of ferrihydrite (relative to its absence)-U(VI) reduction, in fact, becomes almost independent of Ca concentration. The quantitative framework described herein helps to predict the fate and transport of uranium within anaerobic environments.     

Accumulation of Cu and Zn from antifouling paint particles by the marine macroalga,Ulva lactuca

The marine macroalga, Ulva lactuca, has been exposed to different concentrations of antifouling paint particles (4–200 mg L^?1) in the presence of a fixed quantity of clean estuarine sediment and its photosynthetic response and accumulation of Cu and Zn monitored over a period of 2 days. An immediate (<2 h) toxic effect was elicited under all experimental conditions that was quantitatively related to the concentration of contaminated particles present. Likewise, the rate of leaching of both Cu and Zn was correlated with the concentration of paint particles added. Copper accumulation by the alga increased linearly with aqueous Cu concentration, largely through adsorption to the cell surface, but significant accumulation of Zn was not observed. Thus, in coastal environments where boat maintenance is practiced, discarded antifouling paint particles are an important source of Cu, but not Zn, to U. lactuca.     

Dental fluorosis linked to degassing of Ambrym volcano, Vanuatu: a novel exposure pathway

Ambrym in Vanuatu is a persistently degassing island volcano whose inhabitants harvest rainwater for their potable water needs. The findings from this study indicate that dental fluorosis is prevalent in the population due to fluoride contamination of rainwater by the volcanic plume. A dental survey was undertaken of 835 children aged 6–18 years using the Dean’s Index of Fluorosis. Prevalence of dental fluorosis was found to be 96% in the target area of West Ambrym, 71% in North Ambrym, and 61% in Southeast Ambrym. This spatial distribution appears to reflect the prevailing winds and rainfall patterns on the island. Severe cases were predominantly in West Ambrym, the most arid part of the island, and the most commonly affected by the volcanic plume. Over 50 km downwind, on a portion of Malakula Island, the dental fluorosis prevalence was 85%, with 36% prevalence on Tongoa Island, an area rarely affected by volcanic emissions. Drinking water samples from West Ambrym contained fluoride levels from 0.7 to 9.5 ppm F (average 4.2 ppm F, n = 158) with 99% exceeding the recommended concentration of 1.0 ppm F. The pathway of fluoride-enriched rainwater impacting upon human health as identified in this study has not previously been recognised in the aetiology of fluorosis. This is an important consideration for populations in the vicinity of degassing volcanoes, particularly where rainwater comprises the primary potable water supply for humans or animals.     

Preying on commercial fisheries and accumulating paralytic shellfish toxins: a dietary analysis of invasive Dosidicus gigas (Cephalopoda Ommastrephidae) stranded in Pacific Canada

In fall of 2009, several mass strandings of Humboldt squid (Dosidicus gigas) occurred on Vancouver Island (49°7′60N 125°54′0W). Morphological dissections coupled with DNA barcoding of stomach contents revealed Sardinops sagax (Pacific sardine) and Clupea pallasii (Pacific herring) as their primary prey. Plastic nurdles, fishing line, bull kelp, eelgrass, and a guillemot feather were also discovered. The primary prey, Pacific sardines and Pacific herring, are known to bioaccumulate paralytic shellfish toxins (PSTs); additionally, both PSTs and domoic acid (DA) have been implicated in other mass strandings. Therefore, stomach contents, and other tissues when possible, were tested for PSTs and DA. Testing revealed DA concentrations below regulatory guidance levels for human consumption, yet PSTs were well in excess. Though we cannot conclude that PSTs were the definitive cause of the strandings, our findings are the first report of PSTs in D. gigas.     

SNOW AND ICE ALBEDO MEASURED WITH TWO TYPES OF PYRANOMETERS1

ABSTRACT: In order to obtain total short-wave albedos of snow and ice, both incident and reflected solar radiation were measured over a frozen lake surface using two different types of radiation measurement devices: a Kipp and Zonen thermopile pyranometer with a spectral sensitivity of 300 to 2800 nm and a LI-COR photovoltaic pyranometer with a spectral sensitivity of 400 to 1100 am. The spectral response of the LI-COR pyranometers limits its use as a short-wave radiation measurement device. Therefore, two equations were developed to adjust both the daily incident radiation data and the daily reflected radiation data measured by the LI-COR instrument to total short-wave radiation values, i.e., to the waveband of 300 to 2800 nm (visible to near-infrared spectrum). The LI-COR data were then adjusted, and a total short-wave adjusted albedo was calculated with a modeling efficiency of 0.97.     

Reviews

REGIONAL PLANNING: A COMPREHENSIVE VIEW

JEREMY ALDEN and ROBERT MORGAN

Leonard Hill Books, Intertext, London, 1974. £6.

MAN‐MADE FUTURES: READINGS IN SOCIETY, TECHNOLOGY AND DESIGN

NIGEL CROSS, DAVID ELLIOTT and ROBIN ROY (EDS.)

Hutchinson Educational in association with Open University Press, London, 1974. 365 pp., cased £5, paperback £2.75.

CITY OF BIRMINGHAM STRUCTURE PLAN: WRITTEN STATEMENT

NEVILLE BORG (City Engineer)

City of Birmingham, 1973.

DESIGNING FOR HUMAN BEHAVIOUR: ARCHITECTURE AND THE BEHAVIOURAL SCIENCES

(Community Development Series. Series Editor, Richard P. Dober.)

JON LANG, CHARLES BURNETTE, WALTER MOLESKI and DAVID VACHON (EDS.)

Dowden, Hutchinson & Ross, Inc., Stroudsburg, Pa., 1974. 352 pp., S20 (U.K. price not stated).

THE BOOK OF GARDEN ORNAMENT

PETER HUNT (ED.)

J. M. Dent & Co., London, 1974. £9.75.

AMENITY AND URBAN PLANNING

DAVID L. SMITH

Crosby Lockwood Staples, London, 1974. 198 pp. £4.50.     

Water quality changes in a polluted stream over a twenty-five-year period

The Deckers Creek watershed in northern West Virginia (USA), containing a land area of 166 km2 (63 mi2), has a long history of industrial development and attendant environmental abuses from both land and water pollution practices. The water in Deckers Creek was sampled in 1974 at 29 locations along the main stem and resampled in 1999-2000 to determine water quality changes over this 25-year period. Water samples were analyzed for pH, acidity, alkalinity, iron, and calcium at both times, while aluminum, manganese, zinc, and fecal coliform (FC) bacteria densities were added in 1999-2000. Water at almost all sampling points showed lower acidity and metal contents in 1999-2000 compared with 1974. Water pH increased at the mouth from 5.4 in 1974 to 6.0 in 1999-2000. Acidity and iron concentrations were decreased an average of 70% in the upper stretches of the creek. However, one major untreated point source of water from an abandoned underground mining complex continues to degrade the quality of the creek in its lower stretches. In the upper section, the water quality in Deckers Creek has improved due to decreased surface and underground coal mining activities, reclamation of abandoned and recently permitted surface mined lands, and natural healing of past land use scars from timbering and mining over time. The decrease in mineral extraction activities and the reclamation of disturbed lands has occurred due to the passage and enforcement of water quality and land reclamation laws and regulations. More time and additional reclamation projects will continue to enhance the water quality in the creek. Improved water chemistry in the majority of the creek, however, shows the previously unnoticeable biological contamination from sewage inputs.     

Modelling soil series data to facilitate targeted habitat restoration: a polytomous logistic regression approach

Habitat restoration at a landscape scale is becoming increasingly important in environmental management. In this context, geographical information systems are well suited as they can store and integrate many of the abiotic and biotic criteria used to assess the ecological worth of a site. However, this capacity can be limited by the availability or suitability of spatial data sets. A classic example of the latter case is the National Soil Map of England and Wales, which groups soils of a varied nature into associations. Consequently the national soil map has proved to be a poor predictor of habitat suitability. Using polytomous logistic regression we put forward a method for separating soil associations into their constituent soils within the Chilterns Natural Area. This approach used soil association, aspect, slope and relative height as variables for this analysis. Whilst the model's performance is likely to have been limited by the accuracy of the soil association data set, a predictive accuracy of between 47 and 65% is sufficient to facilitate better targeting of habitat restoration when combined with other abiotic factors such as climate and topography.     

Book reviews

Sustainable Industrialisation. David Wallace, 1996, London, Royal Institute of International Affairs, (Earthscan), 120 pp. ISBN 1 85383 352 5, £11.95 (pbk)

Managing Green Technologies for Global Competitiveness. Christian Ndubisi Madu, 1996, London, Quorum Books, distributed by Eurospan, ISBN 0 89930 827 9, £47.95 (hbk)

Greening People, Human Resources and Environmental Management. Walter Wehrmeyer (Ed.) 1996, Sheffield, Greenleaf Publishing, 416 pp. ISBN 1 874719 15 2, £29.50 (hbk)

The Environment for Children: understanding and acting on the environmental hazards that threaten children and their parents. David Satterthwaite, Roger Hart, Caren Levy, Diana Mitlin, David Ross, Jac Smit & Carolyn Stephens, 1996, London, Earthscan Publications, 284 pp. ISBN 1 85383 326 6, £13.95

Local Sustainability: managing and planning ecologically sound places. Paul Selman, 1996, London, Paul Chapman, x + 175pp, index. ISBN 1 85396 300 3, £14.95