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1.
Nature ; 594(7861): 71-76, 2021 06.
Artículo en Inglés | MEDLINE | ID: mdl-34012114

RESUMEN

Micronutrient deficiencies (MNDs) remain widespread among people in sub-Saharan Africa1-5, where access to sufficient food from plant and animal sources that is rich in micronutrients (vitamins and minerals) is limited due to socioeconomic and geographical reasons4-6. Here we report the micronutrient composition (calcium, iron, selenium and zinc) of staple cereal grains for most of the cereal production areas in Ethiopia and Malawi. We show that there is geospatial variation in the composition of micronutrients that is nutritionally important at subnational scales. Soil and environmental covariates of grain micronutrient concentrations included soil pH, soil organic matter, temperature, rainfall and topography, which were specific to micronutrient and crop type. For rural households consuming locally sourced food-including many smallholder farming communities-the location of residence can be the largest influencing factor in determining the dietary intake of micronutrients from cereals. Positive relationships between the concentration of selenium in grain and biomarkers of selenium dietary status occur in both countries. Surveillance of MNDs on the basis of biomarkers of status and dietary intakes from national- and regional-scale food-composition data1-7 could be improved using subnational data on the composition of grain micronutrients. Beyond dietary diversification, interventions to alleviate MNDs, such as food fortification8,9 and biofortification to increase the micronutrient concentrations in crops10,11, should account for geographical effects that can be larger in magnitude than intervention outcomes.


Asunto(s)
Grano Comestible/química , Nutrientes/análisis , Valor Nutritivo , Agricultura , Calcio/análisis , Dieta/estadística & datos numéricos , Etiopía , Humanos , Hierro/análisis , Malaui , Micronutrientes/análisis , Selenio/análisis , Encuestas y Cuestionarios , Triticum/química , Zinc/análisis
2.
Eur J Agron ; 105: 176-188, 2019 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-31007524

RESUMEN

The management of optimal soil pH is fundamental to sustainable crop production. Understanding the lime requirement for arable crops has developed gradually over the last several decades. The aim of this study was to examine the yield-pH relationship for a range of arable crops to understand their response to liming, based on the Long-Term Liming experiments established in 1962 at Rothamsted Research, UK. The main treatments of four different rates of lime and, therefore, four distinctly different soil pH levels were maintained for 35 years at two sites (Rothamsted and Woburn). The pH ranged from 4.4 to 8.0. The lime response was tested on the following crops: spring barley, spring oats, spring beans, spring lupins, winter lupins, potatoes, linseed, winter oilseed rape, winter triticale and winter wheat. Relative yield (RY) was used for non-linear regression analysis to detect site, year and phosphorus (P) fertiliser effects on the relationship with pH. Liming had a highly significant positive effect on soil pH, but overall there was no consistent increase or decrease in soil extractable P (Olsen) or exchangeable K. There were significant site effects detected for RY for most crops which reflect differences in the two soil types. Spring oats and potatoes had very weak responses to lime within the pH range tested. For spring barley, winter triticale, winter wheat and winter oilseed rape significant effects of P fertiliser on the yield-pH relationship were found, although the nature of effects differed between crops and sites. Findings from the Long-Term Liming experiment are invaluable in improving the fundamental understanding on the yield-pH relationship for important arable crops and this has significant implications on selecting crops for rotations. The pH at 90% RY was calculated for selected crops and the beneficial effect of fertiliser P was detected in significantly reducing the critical pH value.

3.
Sci Rep ; 13(1): 2747, 2023 02 16.
Artículo en Inglés | MEDLINE | ID: mdl-36797446

RESUMEN

The form (organic versus inorganic) of minerals (Se, Zn, Cu and Mn), supplemented to sheep (Charolais × Suffolk-Mule (mean weight = 57 ± 2.9 kg) at two European industrial doses, on the return of micronutrients to pasture via nutrient partitioning and composition in sheep urine and faeces was investigated. This gave four treatments in total with 6 animals per treatment (n = 24). The form of the supplemented minerals did not influence the excretory partitioning of micronutrients (Se, Zn, Cu and Mn) between urine and faeces, nor on their concentrations in the excreta. The two doses trialed however, may influence the Se flux in the environment through altering the ratios of Se:P and Se:S ratios in the faeces and Se:S ratio in the urine. Administration of the mineral supplements also improved the retention of P in sheep reducing its excretion via urine. Although the concentrations of readily bioavailable micronutrients in the faeces were not affected by the mineral forms, there were differences in the more recalcitrant fractions of Se, Zn and Cu (as inferred via a sequential extraction) in faeces when different forms of supplemental minerals were offered. The potential impact of these differences on micronutrient flux in pasture requires further investigation.


Asunto(s)
Micronutrientes , Oligoelementos , Animales , Ovinos , Zinc , Alimentación Animal/análisis , Minerales , Suplementos Dietéticos , Heces , Dieta/veterinaria
4.
J Fish Biol ; 80(3): 638-50, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-22380558

RESUMEN

This study assessed the mortality of 157 snapper Pagrus auratus (9-29 cm, total length, L(T) ) after being conventionally angled and then released into cages (along with 48 controls) for 4 days off south-eastern Australia. Fatalities were restricted to 12 angled fish (7·6%) and mostly attributed to the ingestion of hooks and especially their subsequent removal, which caused substantial blood loss and immediate death. Hook ingestion was significantly biased towards smaller fish (<21 cm L(T)) and attributed to a lower chance of anglers initially detecting these individuals on the line (allowing them to consume more of the baits). While mortalities might be reduced in future via (1) choosing terminal rigs that promote mouth hooking and (2) cutting the line on any-hook ingested fish, the results nevertheless validate releasing unwanted angled inshore juvenile P. auratus as a means for managing their exploitation.


Asunto(s)
Conservación de los Recursos Naturales , Perciformes/fisiología , Estrés Fisiológico , Animales , Humanos
5.
Sci Rep ; 12(1): 7986, 2022 05 14.
Artículo en Inglés | MEDLINE | ID: mdl-35568698

RESUMEN

Dietary zinc (Zn) deficiency is widespread globally, and in particular among people in sub-Saharan Africa (SSA). In Malawi, dietary sources of Zn are dominated by maize and spatially dependent variation in grain Zn concentration, which will affect dietary Zn intake, has been reported at distances of up to ~ 100 km. The aim of this study was to identify potential soil properties and environmental covariates which might explain this longer-range spatial variation in maize grain Zn concentration. Data for maize grain Zn concentrations, soil properties, and environmental covariates were obtained from a spatially representative survey in Malawi (n = 1600 locations). Labile and non-labile soil Zn forms were determined using isotopic dilution methods, alongside conventional agronomic soil analyses. Soil properties and environmental covariates as potential predictors of the concentration of Zn in maize grain were tested using a priori expert rankings and false discovery rate (FDR) controls within the linear mixed model (LMM) framework that informed the original survey design. Mean and median grain Zn concentrations were 21.8 and 21.5 mg kg-1, respectively (standard deviation 4.5; range 10.0-48.1). A LMM for grain Zn concentration was constructed for which the independent variables: soil pH(water), isotopically exchangeable Zn (ZnE), and diethylenetriaminepentaacetic acid (DTPA) extractable Zn (ZnDTPA) had predictive value (p < 0.01 in all cases, with FDR controlled at < 0.05). Downscaled mean annual temperature also explained a proportion of the spatial variation in grain Zn concentration. Evidence for spatially dependent variation in maize grain Zn concentrations in Malawi is robust within the LMM framework used in this study, at distances of up to ~ 100 km. Spatial predictions from this LMM provide a basis for further investigation of variations in the contribution of staple foods to Zn nutrition, and where interventions to increase dietary Zn intake (e.g. biofortification) might be most effective. Other soil and landscape factors influencing spatially dependent variation in maize grain Zn concentration, along with factors operating over shorter distances such as choice of crop variety and agronomic practices, require further exploration beyond the scope of the design of this survey.


Asunto(s)
Suelo , Zinc , Grano Comestible/química , Humanos , Malaui , Minerales , Ácido Pentético , Zea mays , Zinc/análisis
6.
Sci Data ; 9(1): 443, 2022 07 25.
Artículo en Inglés | MEDLINE | ID: mdl-35879373

RESUMEN

The dataset comprises primary data for the concentration of 29 mineral micronutrients in cereal grains and up to 84 soil chemistry properties from GeoNutrition project surveys in Ethiopia and Malawi. The work provided insights on geospatial variation in the micronutrient concentration in staple crops, and the potential influencing soil factors. In Ethiopia, sampling was conducted in Amhara, Oromia, and Tigray regions, during the late-2017 and late-2018 harvest seasons. In Malawi, national-scale sampling was conducted during the April-June 2018 harvest season. The concentrations of micronutrients in grain were measured using inductively coupled plasma mass spectrometry (ICP-MS). Soil chemistry properties reported include soil pH; total soil nitrogen; total soil carbon (C); soil organic C; effective cation exchange capacity and exchangeable cations; a three-step sequential extraction scheme for the fractionation of sulfur and selenium; available phosphate; diethylenetriaminepentaacetic acid (DTPA)-extractable trace elements; extractable trace elements using 0.01 M Ca(NO3)2 and 0.01 M CaCl2; and isotopically exchangeable Zn. These data are reported here according to FAIR data principles to enable users to further explore agriculture-nutrition linkages.

7.
Food Chem ; 126(4): 1771-8, 2011 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-25213956

RESUMEN

The retention and speciation of selenium in flour and bread was determined following experimental applications of selenium fertilisers to a high-yielding UK wheat crop. Flour and bread were produced using standard commercial practices. Total selenium was measured using inductively coupled plasma-mass spectrometry (ICP-MS) and the profile of selenium species in the flour and bread were determined using high performance liquid chromatography (HPLC) ICP-MS. The selenium concentration of flour ranged from 30ng/g in white flour and 35ng/g in wholemeal flour from untreated plots up to >1800ng/g in white and >2200ng/g in wholemeal flour processed from grain treated with selenium (as selenate) at the highest application rate of 100g/ha. The relationship between the amount of selenium applied to the crop and the amount of selenium in flour and bread was approximately linear, indicating minimal loss of Se during grain processing and bread production. On average, application of selenium at 10g/ha increased total selenium in white and wholemeal bread by 155 and 185ng/g, respectively, equivalent to 6.4 and 7.1µg selenium per average slice of white and wholemeal bread, respectively. Selenomethionine accounted for 65-87% of total extractable selenium species in Se-enriched flour and bread; selenocysteine, Se-methylselenocysteine selenite and selenate were also detected. Controlled agronomic biofortification of wheat crops for flour and bread production could provide an appropriate strategy to increase the intake of bioavailable selenium.

8.
Nutr Cycl Agroecosyst ; 120(2): 131-144, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34720676

RESUMEN

Liming has widespread and significant impacts on soil processes and crop responses. The aim of this study was to describe the relationships between exchangeable cation concentrations in soil and the relative yield of spring barley. The hypothesis was that yield is restricted by the concentration of a single exchangeable cation in the soil. For simplicity, we focused on spring barley which was grown in nine years of a long-term experiment at two sites (Rothamsted and Woburn). Four liming rates were applied and in each year the relative yield (RY) and the concentrations of exchangeable cations were assessed. Liming had highly significant effects on the concentrations of most exchangeable cations, except for Cu and K. There were significant negative relationships (either linear or exponential) between the exchangeable concentrations of Mn, Cd, Cr, Al, Fe, Cu, Co, Zn and Ni in soil and soil pH. The relationships between RY and the concentrations of selected exchangeable cations (Mn, Ca and Al) were described well using log-logistic relationships. For these cations a significant site effect was probably due to fundamental differences in soil properties. At both sites the concentrations of exchangeable soil Al were excessive (> 7.5 mg kg-1) and were most likely responsible for reduced barley yields (where RY ≤ 0.5) with soil acidification. At Rothamsted barley yield was non-limited (where RY ≥ 1) at soil exchangeable Mn concentrations (up to 417 mg kg-1) greater than previously considered toxic, which requires further evaluation of critical Mn concentrations. SUPPLEMENTARY INFORMATION: The online version of this article (10.1007/s10705-020-10117-2) contains supplementary material, which is available to authorized users.

9.
Sci Total Environ ; 733: 139231, 2020 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-32446063

RESUMEN

Grain and soil were sampled across a large part of Amhara, Ethiopia in a study motivated by prior evidence of selenium (Se) deficiency in the Region's population. The grain samples (teff, Eragrostis tef, and wheat, Triticum aestivum) were analysed for concentration of Se and the soils were analysed for various properties, including Se concentration measured in different extractants. Predictive models for concentration of Se in the respective grains were developed, and the predicted values, along with observed concentrations in the two grains were represented by a multivariate linear mixed model in which selected covariates, derived from remote sensor observations and a digital elevation model, were included as fixed effects. In all modelling steps the selection of predictors was done using false discovery rate control, to avoid over-fitting, and using an α-investment procedure to maximize the statistical power to detect significant relationships by ordering the tests in a sequence based on scientific understanding of the underlying processes likely to control Se concentration in grain. Cross-validation indicated that uncertainties in the empirical best linear unbiased predictions of the Se concentration in both grains were well-characterized by the prediction error variances obtained from the model. The predictions were displayed as maps, and their uncertainty was characterized by computing the probability that the true concentration of Se in grain would be such that a standard serving would not provide the recommended daily allowance of Se. The spatial variation of grain Se was substantial, concentrations in wheat and teff differed but showed the same broad spatial pattern. Such information could be used to target effective interventions to address Se deficiency, and the general procedure used for mapping could be applied to other micronutrients and crops in similar settings.


Asunto(s)
Selenio , Grano Comestible , Etiopía , Suelo , Triticum
10.
New Phytol ; 181(4): 777-794, 2009 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-19207683

RESUMEN

Arsenic (As) is an element that is nonessential for and toxic to plants. Arsenic contamination in the environment occurs in many regions, and, depending on environmental factors, its accumulation in food crops may pose a health risk to humans.Recent progress in understanding the mechanisms of As uptake and metabolism in plants is reviewed here. Arsenate is taken up by phosphate transporters. A number of the aquaporin nodulin26-like intrinsic proteins (NIPs) are able to transport arsenite,the predominant form of As in reducing environments. In rice (Oryza sativa), arsenite uptake shares the highly efficient silicon (Si) pathway of entry to root cells and efflux towards the xylem. In root cells arsenate is rapidly reduced to arsenite, which is effluxed to the external medium, complexed by thiol peptides or translocated to shoots. One type of arsenate reductase has been identified, but its in planta functions remain to be investigated. Some fern species in the Pteridaceae family are able to hyperaccumulate As in above-ground tissues. Hyperaccumulation appears to involve enhanced arsenate uptake, decreased arsenite-thiol complexation and arsenite efflux to the external medium, greatly enhanced xylem translocation of arsenite, and vacuolar sequestration of arsenite in fronds. Current knowledge gaps and future research directions are also identified.


Asunto(s)
Arsénico/metabolismo , Plantas/metabolismo , Acuaporinas/metabolismo , Acuaporinas/fisiología , Arsénico/química , Transporte Biológico , Floema/metabolismo , Fosfatos/metabolismo , Raíces de Plantas/metabolismo , Raíces de Plantas/microbiología , Plantas/genética , Plantas/microbiología , Rizosfera
11.
New Phytol ; 183(2): 340-348, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19402874

RESUMEN

Arsenate tolerance in Holcus lanatus is achieved mainly through suppressed arsenate uptake. We recently showed that plant roots can rapidly efflux arsenite to the external medium. Here, we tested whether arsenite efflux is a component of the adaptive arsenate tolerance in H. lanatus. Tolerant and nontolerant phenotypes were exposed to different arsenate concentrations with or without phosphate for 24 h, and arsenic (As) speciation was determined in nutrient solutions, roots and xylem sap. At the same arsenate exposure concentration, the nontolerant phenotype took up more arsenate and effluxed more arsenite than the tolerant phenotype. However, arsenite efflux was proportional to arsenate uptake and was not enhanced in the tolerant phenotype. Within 2-24 h, most (80-100%) of the arsenate taken up was effluxed to the medium as arsenite. About 86-95% of the As in the roots and majority of the As in xylem sap (c. 66%) was present as arsenite, and there were no significant differences between phenotypes. Arsenite efflux is not adaptively enhanced in the tolerant phenotype H. lanatus, but it could be a basal tolerance mechanism to greatly decrease cellular As burden in both phenotypes. Tolerant and nontolerant phenotypes had a similar capacity to reduce arsenate in roots.


Asunto(s)
Adaptación Fisiológica/efectos de los fármacos , Arseniatos/farmacología , Arsenitos/metabolismo , Holcus/efectos de los fármacos , Holcus/metabolismo , Arseniatos/metabolismo , Fenotipo , Fosfatos/farmacología , Raíces de Plantas/efectos de los fármacos , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/metabolismo , Brotes de la Planta/efectos de los fármacos , Brotes de la Planta/metabolismo , Soluciones , Xilema/efectos de los fármacos , Xilema/metabolismo
12.
J Fish Biol ; 74(1): 220-34, 2009 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-20735535

RESUMEN

Three experiments were done with sand whiting Sillago ciliata: the first two assessed the short-term mortality and physiological response of individuals after being mouth hooked and then subjected to rapid changes in salinity, while the third experiment investigated their longer-term fate after ingesting hooks (independent of salinity changes). In experiment one, 48 tanks containing a single S. ciliata were randomly assigned as either one of three treatments or a control. The fish in treatments one and two were exposed to salinity changes during their angling and subsequent release while those in treatment three were only subjected to angling and air exposure. Control fish remained untouched. Fish were then monitored for up to 6 days for mortalities before blood samples were taken to determine concentrations of plasma cortisol and glucose. Blood samples were also taken from five wild-caught fish to provide baseline estimates of the above variables. None of the treatment or control fish died over the 6 days, and there were no significant differences in blood cortisol or glucose between treatment, control and wild fish. In experiment two, 102 S. ciliata and 52 experimental tanks were used. The treatments were repeated as above, however, six individuals from each treatment and control group were removed and sampled for blood (and then glucose and cortisol) at 0, 24, 48 and 72 h post release. Some changes in behaviour due to the salinity changes occurred as well as a significant main effect of time for cortisol, with all fish having significantly elevated acute stress at the first sample time. In experiment three, 52 S. ciliata were placed into individual tanks. Twenty-six of these fish were allowed to ingest baited J-hooks, played for 60 s, removed from their tanks, and then released after their lines were cut (50 mm from their mouths). Control fish were not touched. All fish were then monitored over 21 days. Six of the treatment fish died (between 3 h and 14 days), while the remaining hooked fish resumed feeding within 5 days and 25% ejected their hooks (between 1 and 19 days). It was concluded that (1) salinity and mouth hooking had few independent or interactive effects on the mortality or physiological response of angled-and-released S. ciliata and (2) while hook ingestion caused some mortalities, the protracted physiological effects were limited, with all surviving fish resuming feeding and some eventually ejecting their hooks.


Asunto(s)
Enfermedades de los Peces/mortalidad , Cuerpos Extraños/veterinaria , Perciformes/fisiología , Salinidad , Estrés Fisiológico , Animales , Glucemia , Hidrocortisona/sangre , Boca/lesiones , Perciformes/anatomía & histología
13.
New Phytol ; 180(2): 434-441, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-18662326

RESUMEN

The hyperaccumulator Pteris vittata translocates arsenic (As) from roots to fronds efficiently, but the form of As translocated in xylem and the main location of arsenate reduction have not been resolved. Here, P. vittata was exposed to 5 microM arsenate or arsenite for 1-24 h, with or without 100 microM phosphate. Arsenic speciation was determined in xylem sap, roots, fronds and nutrient solutions by high-performance liquid chromatography (HPLC) linked to inductively coupled plasma mass spectrometry (ICP-MS). The xylem sap As concentration was 18-73 times that in the nutrient solution. In both arsenate- and arsenite-treated plants, arsenite was the predominant species in the xylem sap, accounting for 93-98% of the total As. A portion of arsenate taken up by roots (30-40% of root As) was reduced to arsenite rapidly. The majority (c. 80%) of As in fronds was arsenite. Phosphate inhibited arsenate uptake, but not As translocation. More As was translocated to fronds in the arsenite-treated than in the arsenate-treated plants. There was little arsenite efflux from roots to the external solution. Roots are the main location of arsenate reduction in P. vittata. Arsenite is highly mobile in xylem transport, possibly because of efficient xylem loading, little complexation with thiols in roots, and little efflux to the external medium.


Asunto(s)
Arseniatos/metabolismo , Arsenitos/metabolismo , Pteris/metabolismo , Análisis de Varianza , Arseniatos/análisis , Arsenitos/análisis , Transporte Biológico/fisiología , Fósforo , Estructuras de las Plantas/química , Estructuras de las Plantas/metabolismo , Xilema/metabolismo
14.
New Phytol ; 178(2): 315-325, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-18266619

RESUMEN

Efficient root-to-shoot translocation is a key trait of the zinc/cadmium hyperaccumulators Thlaspi caerulescens and Thlaspi praecox, but the extent of variation among different accessions and the underlying mechanisms remain unclear. Root-to-shoot translocation of Cd and Zn and apoplastic bypass flow were determined in 10 accessions of T. caerulescens and one of T. praecox, using radiolabels (109)Cd and (65)Zn. Two contrasting accessions (Pr and Ga) of T. caerulescens were further characterized for TcHMA4 expression and metal compartmentation in roots. Root-to-shoot translocation of (109)Cd and (65)Zn after 1 d exposure varied 4.4 to 5-fold among the 11 accessions, with a significant correlation between the two metals, but no significant correlation with uptake or the apoplastic bypass flow. The F(2) progeny from a cross between accessions from Prayon, Belgium (Pr) and Ganges, France (Ga) showed a continuous phenotype pattern and transgression. There was no significant difference in the TcHMA4 expression in roots between Pr and Ga. Compartmentation analysis showed a higher percentage of (109)Cd sequestered in the root vacuoles of Ga than Pr, the former being less efficient in translocation than the latter. Substantial natural variation exists in the root-to-shoot translocation of Cd and Zn, and root vacuolar sequestration may be an important factor related to this variation.


Asunto(s)
Cadmio/metabolismo , Raíces de Plantas/metabolismo , Brotes de la Planta/metabolismo , Thlaspi/metabolismo , Zinc/metabolismo , Cruzamientos Genéticos , Regulación de la Expresión Génica de las Plantas/fisiología , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raíces de Plantas/citología , Thlaspi/clasificación , Thlaspi/genética
15.
Environ Pollut ; 148(1): 221-9, 2007 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-17223237

RESUMEN

Site-specific or soil type-specific ambient background concentrations (ABCs) of trace metals in soils are needed for risk assessment. We investigated three different methods for estimating ABCs in soils using a dataset of 5691 soil samples from England and Wales. The concentrations of Co, Cr and Ni were strongly associated with Al and Fe, and multiple regressions explained 62-85% of their variation, and Al and Fe can therefore be used to predict ABCs for these metals. Soil texture had a major influence on the concentrations of Cd, Co, Cr, Cu, Ni and Zn, and the medians were 3-5 fold higher in clayey than in sandy soils. This was used to predict texture-specific ABCs. Lead concentration was higher in acidic peaty soils than in other soils. A probability graph method was used to estimate ABC for Pb in a population of relatively uncontaminated soils. Potential applications of ABCs are discussed.


Asunto(s)
Monitoreo del Ambiente/métodos , Contaminantes del Suelo/análisis , Oligoelementos/análisis , Aluminio/análisis , Cadmio/análisis , Cromo/análisis , Cobre/análisis , Hierro/análisis , Análisis Multivariante , Níquel/análisis , Tamaño de la Partícula , Medición de Riesgo/métodos , Zinc/análisis
16.
Environ Pollut ; 150(3): 363-72, 2007 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-17379365

RESUMEN

The objectives of this study were to assess the potential for using Thlaspi caerulescens as a phytoextraction plant and develop a user-advice model, which can predict the frequency of phytoextraction operation required under prescribed conditions. Pot and field trials were conducted using soil collected from a dedicated sewage sludge disposal facility. Soil amendments (sulphuric acid, potassium chloride and EDTA) intended to increase Cd solubility were also tested. Predictive models of Cd and Zn uptake were developed which were able to reproduce the observed pH-dependence of Cd uptake with an apparent maximum around pH 6. Chemical treatments did not significantly increase the uptake of Cd. The periodic use of phytoextraction with T. caerulescens to maintain soils below statutory metal concentration limits, when modern sewage sludges are repeatedly applied, seems very attractive given the non-intrusive and cost-effective nature of the process. The major limitations lie with the large-scale husbandry of T. caerulescens.


Asunto(s)
Metales Pesados , Contaminantes del Suelo , Thlaspi/metabolismo , Biodegradación Ambiental , Biomasa , Cadmio/análisis , Quelantes , Ácido Edético , Inglaterra , Concentración de Iones de Hidrógeno , Metales Pesados/análisis , Modelos Teóricos , Cloruro de Potasio , Aguas del Alcantarillado , Contaminantes del Suelo/análisis , Ácidos Sulfúricos , Thlaspi/crecimiento & desarrollo , Zinc/análisis
17.
Environ Pollut ; 141(1): 115-25, 2006 May.
Artículo en Inglés | MEDLINE | ID: mdl-16202493

RESUMEN

Field trials were undertaken to investigate the effect of the application of metal mobilizing agents, different sowing strategies and length of growing season on the extraction of Cd and Zn from soils by Thlaspi caerulescens and Arabidopsis halleri. None of the mobilizing agents used enhanced metal accumulation by T. caerulescens. Between 1998 and 2000, on average across plots where Cd or Zn exceeded allowable limits, T. caerulescens removed 1.3 and 0.3% of the total soil Cd and Zn. In one season when T. caerulescens was grown for 14 months, 21.7 and 4.4% of the total soil Cd and Zn was removed. This was larger than values found when T. caerulescens was grown for 4 months. A. halleri accumulated similar concentrations of Zn, but lower Cd concentrations than T. caerulescens. The results indicate that metal phytoextraction using T. caerulescens can be used to clean up soils moderately contaminated by Cd.


Asunto(s)
Contaminación Ambiental , Residuos Industriales , Metales Pesados , Contaminantes del Suelo , Thlaspi , Arabidopsis/crecimiento & desarrollo , Arabidopsis/metabolismo , Biodegradación Ambiental , Cadmio/metabolismo , Quelantes/farmacología , Ácido Cítrico/farmacología , Ácido Edético/farmacología , Metales Pesados/metabolismo , Ácido Nitrilotriacético/farmacología , Contaminantes del Suelo/metabolismo , Thlaspi/crecimiento & desarrollo , Thlaspi/metabolismo , Zinc/metabolismo
18.
Environ Pollut ; 142(3): 530-9, 2006 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-16321462

RESUMEN

We evaluated the effectiveness of lime and red mud (by-product of aluminium manufacturing) to reduce metal availability to Festuca rubra and to allow re-vegetation on a highly contaminated brown-field site. Application of both lime and red mud (at 3 or 5%) increased soil pH and decreased metal availability. Festuca rubra failed to establish in the control plots, but grew to a near complete vegetative cover on the amended plots. The most effective treatment in decreasing grass metal concentrations in the first year was 5% red mud, but by year two all amendments were equally effective. In an additional pot experiment, P application in combination with red mud or lime decreased the Pb concentration, but not total uptake of Pb in Festuca rubra compared to red mud alone. The results show that both red mud and lime can be used to remediate a heavily contaminated acid soil to allow re-vegetation.


Asunto(s)
Restauración y Remediación Ambiental/métodos , Sedimentos Geológicos , Metales Pesados , Contaminantes del Suelo , Silicatos de Aluminio , Carbonato de Calcio , Arcilla , Festuca/crecimiento & desarrollo , Concentración de Iones de Hidrógeno , Fósforo , Factores de Tiempo
19.
Environ Pollut ; 205: 78-86, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26021819

RESUMEN

Increasing commercial use of nanosilver has focussed attention on the fate of silver (Ag) in the wastewater release pathway. This paper reports the speciation and lability of Ag in archived, stockpiled, and contemporary biosolids from the UK, USA and Australia, and indicates that biosolids Ag concentrations have decreased significantly over recent decades. XANES revealed the importance of reduced-sulfur binding environments for Ag speciation in materials ranging from freshly produced sludge to biosolids weathered under ambient environmental conditions for more than 50 years. Isotopic dilution with (110 m)Ag showed that Ag was predominantly non-labile in both fresh and aged biosolids (13.7% mean lability), with E-values ranging from 0.3 to 60 mg/kg and 5 mM CaNO3 extractable Ag from 1.2 to 609 µg/kg (0.002-3.4% of the total Ag). This study indicates that at the time of soil application, biosolids Ag will be predominantly Ag-sulfides and characterised by low isotopic lability.


Asunto(s)
Plata/química , Contaminantes del Suelo/química , Aguas Residuales/química , Australia , Aguas del Alcantarillado , Plata/análisis , Suelo , Contaminantes del Suelo/análisis , Azufre/análisis , Azufre/química , Factores de Tiempo , Reino Unido , Estados Unidos , Tiempo (Meteorología)
20.
Soil Use Manag ; 31(Suppl Suppl 1): 1-15, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27667890

RESUMEN

National governments are becoming increasingly aware of the importance of their soil resources and are shaping strategies accordingly. Implicit in any such strategy is that degradation threats and their potential effect on important soil properties and functions are defined and understood. In this paper, we aimed to review the principal degradation threats on important soil properties in the UK, seeking quantitative data where possible. Soil erosion results in the removal of important topsoil and, with it, nutrients, C and porosity. A decline in soil organic matter principally affects soil biological and microbiological properties, but also impacts on soil physical properties because of the link with soil structure. Soil contamination affects soil chemical properties, affecting nutrient availability and degrading microbial properties, whilst soil compaction degrades the soil pore network. Soil sealing removes the link between the soil and most of the 'spheres', significantly affecting hydrological and microbial functions, and soils on re-developed brownfield sites are typically degraded in most soil properties. Having synthesized the literature on the impact on soil properties, we discuss potential subsequent impacts on the important soil functions, including food and fibre production, storage of water and C, support for biodiversity, and protection of cultural and archaeological heritage. Looking forward, we suggest a twin approach of field-based monitoring supported by controlled laboratory experimentation to improve our mechanistic understanding of soils. This would enable us to better predict future impacts of degradation processes, including climate change, on soil properties and functions so that we may manage soil resources sustainably.

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