Heavy metal bioavailability and bioaccessibility in soil

This chapter considers the use of a variety of approaches to assess either the bioavailability or the bioaccessibility of metals in soil. The bioavailability of metals from soils is considered with respect to a series of single-extraction methods, including the use of ethylenediaminetetraacetic acid (EDTA), acetic acid, diethylenetriaminepentaacetic acid (DTPA), ammonium nitrate, calcium chloride and sodium nitrate. Then, a procedure for the recovery of metals using a three-stage sequential extraction protocol is described. Two alternate approaches for assessing the environmental health risk to humans by undertaking in vitro gastrointestinal extraction (also known as the physiologically based extraction test, PBET) are considered. Finally, two acid digestion protocols that allow the pseudo-total metal content of samples to be assessed are provided. In all cases details of how the different approaches can be performed are provided, including the specific reagents required (and their preparation), details of the different extraction and acid digestion protocols to be followed and suitable analytical details to allow the measurement of metals by inductively coupled plasma mass spectrometry (ICP-MS) with/without a collision/reaction cell. A detailed Notes section provides experimental details to guide the reader through some of the practical aspects of the procedures. Finally, some experimental results are provided as evidence of the suitability of the approaches described including single-extraction data, using EDTA and acetic acid, for metals in CRM BCR 700. In addition, in vitro gastrointestinal extraction data are provided for metals in CRM SRM 1570A (spinach leaves). The influence of time on the intestinal fluid phase on the recovery of metals in CRM SRM 1570A (spinach leaves) and CRM INCT-TL-1 (tea leaves) is investigated, as well as the repeatability in terms of recovery of metals from soil over a 3-week period by in vitro gastrointestinal extraction

FREEZE! A manifesto for safeguarding and preserving born-digital heritage

Finding ways to preserve born-digital heritage has become a matter of urgency and growing concern. Websites, games and interactive documentaries each bring specific challenges that need to be addressed. It takes three to tango: Ensuring that our digital lives and digital creativity are not lost to future generations requires a joint effort by the principal players: creators, heritage professionals and policy makers. This manifesto lays out the actions they need to take today to safeguard born-digital heritage

Theoretical and experimental study of AC loss in HTS single pancake coils

The electromagnetic properties of a pancake coil in AC regime as a function of the number of turns is studied theoretically and experimentally. Specifically, the AC loss, the coil critical current and the voltage signal are discussed. The coils are made of Bi2Sr2Ca2Cu3O10/Ag (BiSCCO) tape, although the main qualitative results are also applicable to other kinds of superconducting tapes, such as coated conductors. The AC loss and the voltage signal are electrically measured using different pick up coils with the help of a transformer. One of them avoids dealing with the huge coil inductance. Besides, the critical current of the coils is experimentally determined by conventional DC measurements. Furthermore, the critical current, the AC loss and the voltage signal are simulated, showing a good agreement with the experiments. For all simulations, the field dependent critical current density inferred from DC measurements on a short tape sample is taken into account.Comment: 22 pages, 15 figures; contents extended (sections 3.2 and 4); one new figure (figure 5) and two figures replaced (figures 3 and 8); typos corrected; title change

Changes in benthos following the clean-up of a severely metal-polluted cove in the Hudson River estuary: Environmental restoration or ecological disturbance?

We studied changes in macrobenthic communities following the environmental clean-up of metal-polluted (cadmium, nickel, and cobalt) sediments in Foundry Cove, a small inlet within the Hudson River estuary of New York. We used a BACI-style experiment to test the hypotheses that high levels of cadmium in sediments change macrobenthic assemblages relative to unpolluted areas, and removal of metals (especially cadmium) by dredging will restore the benthos, such that benthic fauna in Foundry Cove are not different from unpolluted areas. In 1984, prior to the restoration work, there were no significant differneces between macrobenthic assemblages in polluted and unpolluted locations, indicating that cadmium had little effect on community structure. The lack of an observed toxicity effect may have been caused by the compensatory evolution of resistance to cadmium in dominant organisms. Six years after the restoration work and despite a substantial reduction in metal pollution, there were lower abundances of oligochaetes, nematodes, and chironomids and a higher abundance of polychaetes at Foundry Cove relative to reference locations. Correlative analyses identified greater sediment compaction caused by dredging at Foundry, Cove as a possible cause of faunal differences

Bottlenecks in the provision of quality mental health services in Eritrea

Background: The prevalence of mental disorders is increasing significantly in developing countries due to the frequently occurring major risk factors. There is no published information on the profile of mental health disorder and services in Eritrea. Objective of the study: Follow-up descriptive study was conducted on one hundred and one consecutive children with advanced HIV disease who were put on antiretroviral therapy from September 2005 to October 2006. These patients were followed up at the antiretroviral therapy (ART) clinic of the hospital. Methods: A descriptive cross sectional study was conducted using the WHO-AIMS questionnaire that was administered to relevant stakeholders. Results: There was no comprehensive mental health policy and legislation in Eritrea. Only 5% of the health services budget is allocated for mental health services. Mental health services is free of charge and were provided integrated with Primary Health Care services. Inadequate human resources and inadequate training on mental health for the health workers were among the constraints. Conclusion: The status of mental disorders and the mental health services in Eritrea from the policy to management guidelines requires urgent review. Significant Outcomes: a) In resource limited settings, the integrated primary health care approach for mental health services is cost effective and avoids associated stigma. b) WHO/AIMS tool is a simple tool that provides complete picture of the mental health system of a country, c) Lack of policies and legislation in a country severely affects the mental health system of a country Limitations: This was a cross sectional study where data collection and analysis was partially restricted by the level and quality of information available in the registry books of the health facilities. Key words: WHO-AIMS, integrated primary health care, mental health services