Iodine dynamics in the terrestrial environment

The aim of this work was to investigate the effect of soil properties on soil iodine dynamics and uptake to plants. Soil and vegetation samples were collected from across eastern Northern Ireland (NI) to form the basis of most experimental work; samples from the Rothamsted Park Grass archive were used to investigate the role of changing soil chemistry through time and due to selected fertiliser applications; and iodine dynamics in humic acid (HA) were studied to improve understanding of the role of organic matter in soils. Input of iodine in rainfall was considered in the context of samples from both locations, and the additional influences of coastal proximity, soil type and underlying geology were reviewed for the NI samples. Total iodine analysis was carried out using extraction with TMAH and quantification by ICP-MS; aqueous iodine speciation was determined using HPLC and SEC coupled with ICP-MS. The most important iodine inputs to both soil and vegetation were found to be directly from the sea in coastally-exposed locations, and from rainfall in other cases. Soil organic matter (measured as soil organic carbon, SOC) was determined to be involved in both retaining a portion of recalcitrant iodine in soil and HA, and in promoting sorption of both iodide and iodate in highly organic soils. Metal oxides (Fe, Mn and Al) were found to be important in rapid sorption of iodate to soils with SOC ≤ 38 %, and there was an indication that they may be involved in promoting the reaction of iodide with organic matter. Replenishment of a transient phyto-available pool was essential for provision of iodine to vegetation. The availability of recently added iodine (as 129IO3-) in the pot experiment was controlled by its sorption onto the solid phase, and near-constant input from irrigation water was the major source of vegetation iodine in most cases. Rainfall was shown to be important in controlling vegetation iodine concentrations in field situations. In soils collected from very coastally-exposed locations, the soil iodine concentration was extremely high and therefore a greater proportion of labile native iodine was available for uptake; irrigation sources were much less important. This work improves understanding of soil iodine dynamics and the important factors controlling iodine speciation and availability to plants. Results can be used to inform practices regarding provision of iodine to crops for both humans and grazing animals

Historical trends in iodine and selenium in soil and herbage at the Park Grass experiment, Rothamsted Research, UK

Long term trends in iodine and selenium retention in soil, and uptake by herbage, were investigated in archived samples from the Park Grass Experiment, initiated in 1856 at Rothamsted, UK. Soil (0-23 cm) and herbage samples from plots receiving various mineral fertilisers and organic manures, with and without lime, were analysed for Se and iodine (I) to assess the effect of soil amendment, annual rainfall, crop yield and changes in soil chemistry from 1876 to 2008. Comparing soil from limed and un-limed control (unfertilized) plots, TMAH-extractable Se and I concentrations both diverged, with time, with greater retention in un-limed plots; differences in concentration amounted to 92 and 1660 µg kg-1 for Se and I respectively after 105 yr. These differences were broadly consistent with estimated additions from rainfall and dry deposition. Offtake of both elements in herbage was negligible compared to soil concentrations and annual inputs (<0.003% of total soil I and <0.006% of total soil Se). A positive correlation was observed between I and Se concentrations in herbage, suggesting some common factors controlling bioavailability. A growth-dilution effect for I and Se was suggested by the positive correlation between growing season rainfall (GSR) and herbage yield together with soil-to-plant transfer factors decreasing with yield. Phosphate and sulphate fertilizers reduced I and Se herbage concentrations, both through ion competition and increased herbage yield. Results suggest that in intensive agriculture with soil pH control, the I requirement of grazing animals is not likely to be met by herbage alone

Wordless intervention for epilepsy in learning disabilities (WIELD):study protocol for a randomized controlled feasibility trial

Epilepsy is the most common neurological problem that affects people with learning disabilities. The high seizure frequency, resistance to treatments, associated skills deficit and co-morbidities make the management of epilepsy particularly challenging for people with learning disabilities. The Books Beyond Words booklet for epilepsy uses images to help people with learning disabilities manage their condition and improve quality of life. Our aim is to conduct a randomized controlled feasibility trial exploring key methodological, design and acceptability issues, in order to subsequently undertake a large-scale randomized controlled trial of the Books Beyond Words booklet for epilepsy

Iodine dynamics in the terrestrial environment

The aim of this work was to investigate the effect of soil properties on soil iodine dynamics and uptake to plants. Soil and vegetation samples were collected from across eastern Northern Ireland (NI) to form the basis of most experimental work; samples from the Rothamsted Park Grass archive were used to investigate the role of changing soil chemistry through time and due to selected fertiliser applications; and iodine dynamics in humic acid (HA) were studied to improve understanding of the role of organic matter in soils. Input of iodine in rainfall was considered in the context of samples from both locations, and the additional influences of coastal proximity, soil type and underlying geology were reviewed for the NI samples. Total iodine analysis was carried out using extraction with TMAH and quantification by ICP-MS; aqueous iodine speciation was determined using HPLC and SEC coupled with ICP-MS. The most important iodine inputs to both soil and vegetation were found to be directly from the sea in coastally-exposed locations, and from rainfall in other cases. Soil organic matter (measured as soil organic carbon, SOC) was determined to be involved in both retaining a portion of recalcitrant iodine in soil and HA, and in promoting sorption of both iodide and iodate in highly organic soils. Metal oxides (Fe, Mn and Al) were found to be important in rapid sorption of iodate to soils with SOC ≤ 38 %, and there was an indication that they may be involved in promoting the reaction of iodide with organic matter. Replenishment of a transient phyto-available pool was essential for provision of iodine to vegetation. The availability of recently added iodine (as 129IO3-) in the pot experiment was controlled by its sorption onto the solid phase, and near-constant input from irrigation water was the major source of vegetation iodine in most cases. Rainfall was shown to be important in controlling vegetation iodine concentrations in field situations. In soils collected from very coastally-exposed locations, the soil iodine concentration was extremely high and therefore a greater proportion of labile native iodine was available for uptake; irrigation sources were much less important. This work improves understanding of soil iodine dynamics and the important factors controlling iodine speciation and availability to plants. Results can be used to inform practices regarding provision of iodine to crops for both humans and grazing animals.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

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Letter to the editor

Global economic burden of unmet surgical need for appendicitis

Background There is a substantial gap in provision of adequate surgical care in many low- and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capital approach was applied, focusing on the economic burden resulting from premature death and absenteeism. Results Excess mortality was 4185 per 100 000 cases of appendicitis using approach 1 and 3448 per 100 000 using approach 2. The economic burden of continuing current levels of access and local quality was US $92 492 million using approach 1 and$73 141 million using approach 2. The economic burden of not providing surgical care to the standards of high-income countries was $95 004 million using approach 1 and$75 666 million using approach 2. The largest share of these costs resulted from premature death (97.7 per cent) and lack of access (97.0 per cent) in contrast to lack of quality. Conclusion For a comparatively non-complex emergency condition such as appendicitis, increasing access to care should be prioritized. Although improving quality of care should not be neglected, increasing provision of care at current standards could reduce societal costs substantially

Global economic burden of unmet surgical need for appendicitis

Background There is a substantial gap in provision of adequate surgical care in many low- and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capital approach was applied, focusing on the economic burden resulting from premature death and absenteeism. Results Excess mortality was 4185 per 100 000 cases of appendicitis using approach 1 and 3448 per 100 000 using approach 2. The economic burden of continuing current levels of access and local quality was US $92 492 million using approach 1 and$73 141 million using approach 2. The economic burden of not providing surgical care to the standards of high-income countries was $95 004 million using approach 1 and$75 666 million using approach 2. The largest share of these costs resulted from premature death (97.7 per cent) and lack of access (97.0 per cent) in contrast to lack of quality. Conclusion For a comparatively non-complex emergency condition such as appendicitis, increasing access to care should be prioritized. Although improving quality of care should not be neglected, increasing provision of care at current standards could reduce societal costs substantially