Preventing chronic malnutrition in children under 2 years in rural Angola (MuCCUA trial): protocol for the economic evaluation of a three-arm community cluster randomised controlled trial.

INTRODUCTION: Chronic malnutrition is a serious problem in southern Angola with a prevalence of 49.9% and 37.2% in the provinces of Huila and Cunene, respectively. The MuCCUA (Mother and Child Chronic Undernutrition in Angola) trial is a community-based randomised controlled trial (c-RCT) which aims to evaluate the effectiveness of a nutrition supplementation plus standard of care intervention and a cash transfer plus standard of care intervention in preventing stunting, and to compare them with a standard of care alone intervention in southern Angola. This protocol describes the planned economic evaluation associated with the c-RCT. METHODS AND ANALYSIS: We will conduct a cost-efficiency and cost-effectiveness analysis nested within the MuCCUA trial with a societal perspective, measuring programme, provider, participant and household costs. We will collect programme costs prospectively using a combined calculation method including quantitative and qualitative data. Financial costs will be estimated by applying activity-based costing methods to accounting records using time allocation sheets. We will estimate costs not included in accounting records by the ingredients approach, and indirect costs incurred by beneficiaries through interviews, household surveys and focus group discussions. Cost-efficiency will be estimated as cost per output achieved by combining activity-specific cost data with routine data on programme outputs. Cost-effectiveness will be assessed as cost per stunting case prevented. We will calculate incremental cost-effectiveness ratios comparing the additional cost per improved outcome of the different intervention arms and the standard of care. We will perform sensitivity analyses to assess robustness of results. ETHICS AND DISSEMINATION: This economic evaluation will provide useful information to the Angolan Government and other policymakers on the most cost-effective intervention to prevent stunting in this and other comparable contexts. The protocol was approved by the República de Angola Ministério da Saúde Comité de Ética (27C.E/MINSA.INIS/2022). The findings of this study will be disseminated within academia and the wider policy sphere. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov Registry (NCT05571280).

Evaluation of the rhizospheric microbiome of the native colonizer Piptatherum miliaceum in semiarid mine tailings.

The study of the rhizospheric microbiome in native plants should be a prerequisite before carrying out the phytomanagement of mine tailings. The goal of this work was to evaluate the rhizospheric microbiome of Piptatherum miliaceum in semiarid mine tailings. A comprehensive edaphic characterization was performed including the description of soil microbial composition in the rhizosphere of P. miliaceum growing at a mine tailings pile and at a control site. Plant nutritional and isotopic compositions were also determined. Neutral pH of the tailings (7.3) determined low metal extractability in 0.01 M CaCl2 (e.g. < 1 mg/kg for Zn). In spite of the contrasting edaphic fertility conditions of both sites, N (~ 15 g kg-1) and P (~ 400 mg kg-1) leaf concentrations were similar. The lower δ15N at the tailings plants (- 4.50‰) compared to the control (6.42‰) indicated greater efficiency of P. miliaceum for uptaking N under the low fertility conditions of the tailings (0.1% total soil nitrogen). The presence at the tailings of bacterial orders related to the cycling of N, such as Rhizobiales, could have contributed to enhance N acquisition. The lower leaf δ13C values at the tailings (- 30.22‰) compared to the control (- 28.47‰) indicated lower water use efficiency of the tailing plants. Some organotrophic bacterial and fungal groups in the tailings' rhizospheres were also found in the control site (e.g. Cytophagales, Sphingobacteriales for bacteria; Hypocreales, Pleosporales for fungi). This may indicate that P. miliaceum is able to shape its own specific microbiome at the tailings independently from the initial microbial composition of the tailings.

Effects on metal availability of the application of tree biochar and municipal waste biosolid in a metalliferous mine tailings substrate.

The phytostabilization of mine tailings requires a previous assessment of the effects of soil amendments on metal mobility. The goal of this work was to evaluate the response of metal availability (both labile and potentially available pools) to the addition of two organic amendments (a municipal waste biosolid and a tree biochar), separately and in combination, in a mine tailings substrate. For this purpose, a comprehensive comparison among several single extraction procedures and a sequential extraction procedure was performed. The effects on metals phytotoxicity were assessed through a germination test using seeds of Zygophyllum fabago. When evaluating the effect of the amendments in the labile metal pool, the biochar resulted effective in decreasing metal-extractable concentrations, especially for Cd, Mn and Zn. The treatment with biochar also showed better germination parameters (percentage of germinated seeds and sooner germination) than the rest of the unamended and amended treatments. The use of the municipal organic biosolid increased labile metal concentrations and potentially available metal pools assessed with EDTA and did not contribute to achieve better results of seed germination. Compared to the single biosolid treatment, the combination of biochar/biosolid modulated some labile metal concentrations and showed similar germination parameters to those obtained for the treatment amended only with biochar. This positive effect of biochar in modulating the soluble metal concentrations associated with certain urban/agricultural organic materials supported the suitability of using these combinations in field applications, although a higher rate of biochar application would be recommended to obtain a more beneficial effect.

Effects of a soil organic amendment on metal allocation of trees for the phytomanagement of mining-impacted soils.

The suitable application of phytomanagement by phytostabilisation using plant tree species in metal-polluted soils requires an assessment of the fate of metals in biological tree compartments. The goal of this work was to evaluate the effect of an urban compost amendment on metal allocation in two evergreen tree species (Pinus halepensis and Tetraclinis articulata) growing in a metal-enriched polluted substrate. A comprehensive characterisation of edaphic parameters and metal speciation was carried out. Plant analyses included metal concentrations in different tree compartments: roots, stems, branches and leaves. The amendment caused a significant increase in plant biomass for both trees, although T. articulata produced 2.5 times more biomass than P. halepensis. The amendment alleviated P deficiency in P. halepensis. This did not occur for the N deficiency detected in T. articulata. The latter showed no effect of the amendment in the allocation of metals, being most of them restricted at the root compartment (> 50%). For P. halepensis, similar behaviour occurred for Cu, Pb and Zn. However, for Cd, the amendment caused its redistribution into pine shoots, probably due to its transport associated with the increased transpiration. Results indicated that T. articulata may be a promising tree species to be used in phytomanagement programs under semiarid climates due to its low metal translocation into shoots and remarkable biomass production under amendment conditions.

Nutrient limitation determines the suitability of a municipal organic waste for phytomanaging metal(loid) enriched mine tailings with a pine-grass co-culture.

The suitable phytomanaging of mine tailings not only requires an improvement of soil fertility but also the assessment of the biotic interactions between the selected plant species. This study aimed to evaluate the effect of an organic amendment on the response of two plant species of contrasting habit, a tree, Pinus halepensis and a grass, Piptatherum miliaceum growing on a metal(loid)-contaminated substrate collected from mine tailings. Pots containing single plant individuals or their combination, with and without organic amendment (at 10% rate), were established and grown in a greenhouse for 13 months. Plant biomass, foliar ionome, leaf δ15N and metal(loid) concentrations were measured at the end of the experiment. The amendment alleviated P deficiency in the substrate and strongly stimulated biomass production by both plant species (10-fold for pine; 90-fold for the grass), leading to more balanced N/P ratios in leaves (especially for the grass). Co-culture with the grass negatively affected pine growth, decreasing total biomass and leaf δ15N values and inducing severe N deficiency (leaf N/P ratio<10). In contrast, co-culture with pine improved the nutrient status and growth of the grass, but only under non-amended conditions. Needle metal(loid) concentrations in P. halepensis were affected by both amendment addition and co-culture with the grass. High biomass growth with low metal(loid) concentrations in P. miliaceum leaves for the amended treatment makes this grass species suitable for the phytomanagement of metal(loid) polluted tailings, since it achieves high biomass production together with low concentrations of metal(loid)s in edible/senescent parts.

Biochar from sewage sludge and pruning trees reduced porewater Cd, Pb and Zn concentrations in acidic, but not basic, mine soils under hydric conditions.

This study aimed to assess the effectiveness of biochar from sewage sludge -BSS- and from pruning trees -BPT- (addition dose of 6% d.w.) to immobilise metals in acidic (pH ∼ 4.7) and basic (pH ∼ 7.4) mine soils under variable flooding conditions, and to determine biochar influence on plant (Sarcocornia fruticosa -Sf-) growth and metal uptake. BSS had lower pH (∼8.2 vs. ∼ 9.8), CaCO3 (∼71 vs. ∼ 85 g kg-1), total organic carbon (∼354 vs. ∼ 656 g kg-1) and higher water soluble organic carbon (WSOC ∼ 0.15 vs ∼ 0.06 mg kg-1) than BPT. PVC columns (15 × 30 cm) were prepared with the following treatments (n = 4): 1) no Biochar-no Sf; 2) no Biochar-Sf; 3) BSS-no Sf; 4) BSS-Sf; 5) BPT-no Sf; 6) BPT-Sf. Changes in water table level (WL) were simulated for 303 days with tap water (upper 0-15 cm alternating flooding-drying conditions, lower 15-30 cm always underwater). The pH, redox potential (Eh), temperature and porewater WSOC, Zn, Cd and Pb concentrations were regularly measured, and plants were removed at the end and length, fresh weight and metal concentrations in tissues measured. In the basic soil, there were no consistent evidences that BSS and BPT were effective decreasing porewater metal concentrations and reducing metal uptake in plants. Sf contributed to mobilise Zn, and in less extent Cd, in the upper soil layer, regardless of the type of biochar, and this effect increased with aging. In the acidic soil, BSS and BPT were effective increasing the pH and decreasing porewater metals. BSS increased its efficiency with aging, which can be mainly attributable to the more reduced conditions that induced (lower Eh values) due to its higher WSOC content. Biochar was effective hindering metal mobilisation by Sf and reducing plant's metal uptake (e.g. reduction in roots: ∼7 fold for Zn, ∼19-fold for Cd and ∼ 2-fold for Pb). BSS was more effective promoting Sf growth (fresh weight) than BPT. Therefore, in relation with the use of biochar from sewage sludge and from pruning trees as soil amendments under flooding-non flooding conditions, we can conclude that it can be a useful option in acidic mine soils for decreasing water soluble metals and improving plant growth. However, in basic mine soils, we have no evidences to support the advantages of using these two types of biochar as amendments. Hence, the use of biochar in metal-polluted wetlands has environmental implications that must be planned for each specific case in order to optimize the positive aspects (wetland as sinks of pollutants) and reduce the drawbacks (wetland as source of pollutants).

Coordinated role of soluble and cell wall bound phenols is a key feature of the metabolic adjustment in a mining woody fleabane (Dittrichia viscosa L.) population under semi-arid conditions.

Environmental contamination by hazardous heavy metals/metalloids (metal(loid)s) is growing worldwide. To restrict the migration of toxic contaminants, the establishment of a self-sustainable plant cover is required. Plant growth in multi-polluted soils is a challenging issue not only by metal(loid) toxicities, but also by the co-occurrence of other stressors. Dittrichia viscosa is a pioneer Mediterranean species able to thrive in metal(loid)-enriched tailings in semi-arid areas. The aim of the present work was to examine the metabolic adjustments involved in the acclimation responses of this plant to conditions prevailing in mine-tailings during Mediterranean spring and summer. For this purpose, fully-expanded leaves, and rhizosphere soil of both mining and non-mining populations of D. viscosa grown spontaneously in south-eastern Spain were sampled in two consecutive years. Quantitative analysis of >50 biochemical, physiological and edaphic parameters were performed, including nutrient status, metal(loid) contents, leaf redox components, primary and secondary metabolites, salicylic acid levels, and soil physicochemical properties. Results showed that mining plants exhibited high foliar Zn/Pb co-accumulation capacity, without substantially affecting their photosynthetic metabolism or nutritional status even in the driest summer period. The comparison of the antioxidative/oxidative profile between mining and non-mining D. viscosa populations revealed no major seasonal changes in the content of primary antioxidants (ascorbate and GSH), or in the levels of ROS. Multivariate analysis showed that phenylalanine ammonia-lyase (PAL) and peroxidase (PRX) activities and soluble and cell wall-bound phenols were potential biomarkers for discriminating between both populations. During the dry season, a marked enhancement in the activity of both PAL and soluble PRX resulted in both a drop in the accumulation of soluble phenols and an increase of the strong metal chelator caffeic acid in the cell-wall fraction, supporting the view that the plasticity of phenylpropanoid metabolism provide an effective way to counteract the effects of stress combinations.

Importance of intra- and interspecific plant interactions for the phytomanagement of semiarid mine tailings using the tree species Pinus halepensis.

The objective of this work was to evaluate the effects of plant interactions (intra- and interspecific) on the growth and metal(loid) uptake of the tree species Pinus halepensis to determine its suitability for the phytomanagement of semiarid mine tailings. The pioneer tailings colonizer grass Piptatherum miliaceum was selected for assessing interspecific interactions. The experiment was conducted following a pot experimental design employing mine tailings soil. Pots containing single individuals of P. halepensis or P. miliaceum and pots containing combinations with pines (two pines per pot, or one pine and one grass per pot) were used. The analyses included the determination of plant biomass, foliar element status and stable isotope composition, metal(loid) uptake and its translocation to different plant organs. P. halepensis strongly favoured the growth of P. miliaceum by increasing 9-fold the latter's biomass and alleviating its P limitation. In this interspecific treatment P. halepensis showed a strong N limitation (N/P = 7), which negatively affected its growth, (to about half the biomass of that obtained for the other treatments) and exhibited a significant increase in some metals translocation (especially Cd) into aerial parts. Interestingly, P. miliaceum showed a decrease in the root to leaves translocation factor for most of metals when growing together with pines. The effects of the intraespecific combination on growth and metal uptake in P. halepensis were less relevant than those obtained for the interspecific one. Further research should be focused on testing the behaviour of plant co-cultures under the addition of N or P amendments which could alleviate the negative effects of plant competition.

Infecciones virales respiratorias en una cohorte de niños durante el primer año de vida y su papel en el desarrollo de sibilancias / Respiratory viral infections in a cohort of children during the first year of life and their role in the development of wheezing

Introducción: Las infecciones respiratorias virales que requieren hospitalización parecen conferir riesgo de desarrollar sibilancias recurrentes, pero existen pocos datos publicados en poblaciones no seleccionadas por tener factores de riesgo. Nuestro objetivo principal fue analizar si las infecciones respiratorias virales sintomáticas y asintomáticas, de diferente gravedad, durante el primer año de vida en una cohorte de recién nacidos, suponen un mayor riesgo de sibilancias recurrentes. Pacientes y métodos: Se incluyeron 302 recién nacidos. Se recogió aspirado nasofaríngeo a los niños cuando presentaron una infección respiratoria y de forma periódica en los controles de salud (2, 4, 6 y 12 meses). Se estudiaron 16 virus respiratorios mediante reacción en cadena de polimerasa (PCR). Resultados: Se analizaron 1.293 muestras (1.005 controles de salud y 288 infecciones respiratorias). El 30,8% de las muestras tomadas en los controles de salud fueron positivas, frente a un 77,8% en las infecciones respiratorias, p < 0,001 (OR: 3, IC 95%: 2,4-3,8). Un total de 239 (79%) lactantes tuvieron al menos una detección viral positiva durante el primer año de vida. El virus más frecuentemente identificado (71%) fue el rinovirus (RV). En 27 lactantes (11%) se detectaron sibilancias recurrentes durante su primer año de vida (2,9 DE: 1,2 episodios). El 58,3% de los lactantes cuya primera infección respiratoria requirió hospitalización desarrollaron sibilancias de repetición, frente al 8,6% de los niños cuya primera infección fue leve o asintomática, p < 0,001 (OR: 2,18; lC 95%: 1,05-4,5). Conclusiones: En nuestra serie, las infecciones respiratorias virales graves en los primeros meses de vida supusieron un factor de riesgo para desarrollar sibilancias recurrentes. No ocurrió lo mismo con las infecciones respiratorias leves (AU)

Introduction: It is known that infants with viral respiratory infections severe enough to require hospital admission have a high risk of developing recurrent wheezing. Few data have been published on unselected populations. The main aim of this study was to analyse symptomatic and asymptomatic respiratory viral infections during the first year of life in a cohort of infants, recruited at birth, and the development of recurrent wheezing. Patients and methods: A total of 302 newborns were recruited. A nasopharyngeal aspirate was taken when the patients had a respiratory infection, as well as in the visits for vaccination at 2, 4, 6, and 12 months. RT-nested PCR assays were performed to detect 16 viruses. Results: A total of 1,293 samples were analysed (1,005 healthy controls and 288 respiratory infections). Samples taken during routine check-ups were positive in 30.8% of cases, while those with respiratory infection were positive in 77.8%, P < .001 (OR: 3, 95% CI: 2.4-3.8). A total of 239 (79%) infants had at least 1 positive respiratory viral infection detected. The most frequent virus (71%) was rhinovirus (RV). Recurrent wheezing was found in 27 (11%) children during their first year of life (1.2 episodes, SD 2.9). Recurrent wheezing was present in 58.3% of patients admitted to hospital during their first viral infection, vs. 8.6% of infants when the first infection was mild or who had asymptomatic viral detection, P < .001 (OR: 2.18; 95% CI: 1.05-4.5). Conclusions: In our series, severe respiratory infections leading to hospitalisation in the first months of life are risk factors for developing wheezing, but not in the case of mild RV infections (AU)

Phosphorus retention and fractionation in an eutrophic wetland: A one-year mesocosms experiment under fluctuating flooding conditions.

This study aimed to evaluate the response of salt marshes to pulses of PO43--enriched water, with and without the presence of Phragmites australis. A one-year mesocosms experiment was performed in simulated soil profiles (fine-textured surface layers and sandy subsurface layers) from a coastal salt marsh of the Mar Menor lagoon under alternating flooding-drying conditions with eutrophic water, under low (1.95 mg L-1 P-PO43-) and high (19.5 mg L-1 P-PO43-) P load, and with the presence/absence of Phragmites. The PO43- concentrations in soil porewater and drainage water were regularly measured, and P accumulated in soils (including a fractionation procedure) and plants (roots, rhizomes, stems and leaves) were analyzed. The experimental mesocosms were highly effective in the removal of P from the eutrophic flooding water (>90% reduction of the P added to the system both in the soil pore water and drainage water), regardless of the nutrient load, the season of the year and the presence/absence of Phragmites. The soil was the main sink of the P added to the system, while Phragmites had a minor role in P removal. The biomass of Phragmites accumulated ∼27% of the P added with the flooding water in the treatment with water of low P load while ∼12% of P in that of high P load; the rhizomes were the organs that contributed the most (∼67-72% of the total P retained by the plants). Ca/Mg compounds were the main contributors to the retention of P in the soil compartment, especially in the fine-textured surface soil layers (∼34-53% of the total P in the soil was present in this fraction). Phragmites favored the retention of P onto metal oxides (∼12% increase of the P retained in the metal oxides fraction in the treatment with water of high P load). Hence, the use of constructed wetlands to ameliorate the negative impacts of P-enriched waters in the Mar Menor lagoon and similar areas is recommended. We propose the incorporation of fine-textured carbonated materials, with high content of Ca/Mg compounds, and the use of Phragmites to favor the retention of P by these systems.

Respiratory viral infections in a cohort of children during the first year of life and their role in the development of wheezing.

INTRODUCTION: It is known that infants with viral respiratory infections severe enough to require hospital admission have a high risk of developing recurrent wheezing. Few data have been published on unselected populations. The main aim of this study was to analyse symptomatic and asymptomatic respiratory viral infections during the first year of life in a cohort of infants, recruited at birth, and the development of recurrent wheezing. PATIENTS AND METHODS: A total of 302 newborns were recruited. A nasopharyngeal aspirate was taken when the patients had a respiratory infection, as well as in the visits for vaccination at 2, 4, 6, and 12 months. RT-nested PCR assays were performed to detect 16 viruses. RESULTS: A total of 1293 samples were analysed (1005 healthy controls and 288 respiratory infections). Samples taken during routine check-ups were positive in 30.8% of cases, while those with respiratory infection were positive in 77.8%, P < .001 (OR: 3, 95% CI: 2.4-3.8). A total of 239 (79%) infants had at least 1 positive respiratory viral infection detected. The most frequent virus (71%) was rhinovirus (RV). Recurrent wheezing was found in 27 (11%) children during their first year of life (1.2 episodes, SD 2.9). Recurrent wheezing was present in 58.3% of patients admitted to hospital during their first viral infection, vs. 8.6% of infants when the first infection was mild or who had asymptomatic viral detection, P < .001 (OR: 2.18; 95% CI: 1.05-4.5). CONCLUSIONS: In our series, severe respiratory infections leading to hospitalisation in the first months of life are risk factors for developing wheezing, but not in the case of mild RV infections.

INTRODUCCIÓN: Las infecciones respiratorias virales que requieren hospitalización parecen conferir riesgo de desarrollar sibilancias recurrentes, pero existen pocos datos publicados en poblaciones no seleccionadas por tener factores de riesgo. Nuestro objetivo principal fue analizar si las infecciones respiratorias virales sintomáticas y asintomáticas, de diferente gravedad, durante el primer año de vida en una cohorte de recién nacidos, suponen un mayor riesgo de sibilancias recurrentes. PACIENTES Y MÉTODOS: Se incluyeron 302 recién nacidos. Se recogió aspirado nasofaríngeo a los niños cuando presentaron una infección respiratoria y de forma periódica en los controles de salud (2, 4, 6 y 12 meses). Se estudiaron 16 virus respiratorios mediante reacción en cadena de polimerasa (PCR). RESULTADOS: Se analizaron 1.293 muestras (1.005 controles de salud y 288 infecciones respiratorias). El 30,8% de las muestras tomadas en los controles de salud fueron positivas, frente a un 77,8% en las infecciones respiratorias, p < 0,001 (OR: 3, IC 95%: 2,4-3,8). Un total de 239 (79%) lactantes tuvieron al menos una detección viral positiva durante el primer año de vida. El virus más frecuentemente identificado (71%) fue el rinovirus (RV). En 27 lactantes (11%) se detectaron sibilancias recurrentes durante su primer año de vida (2,9 DE: 1,2 episodios). El 58,3% de los lactantes cuya primera infección respiratoria requirió hospitalización desarrollaron sibilancias de repetición, frente al 8,6% de los niños cuya primera infección fue leve o asintomática, p < 0,001 (OR: 2,18; lC 95%: 1,05-4,5). CONCLUSIONES: En nuestra serie, las infecciones respiratorias virales graves en los primeros meses de vida supusieron un factor de riesgo para desarrollar sibilancias recurrentes. No ocurrió lo mismo con las infecciones respiratorias leves.

[Respiratory viral infections in a cohort of children during the first year of life and their role in the development of wheezing]. / Infecciones virales respiratorias en una cohorte de niños durante el primer año de vida y su papel en el desarrollo de sibilancias.

INTRODUCTION: It is known that infants with viral respiratory infections severe enough to require hospital admission have a high risk of developing recurrent wheezing. Few data have been published on unselected populations. The main aim of this study was to analyse symptomatic and asymptomatic respiratory viral infections during the first year of life in a cohort of infants, recruited at birth, and the development of recurrent wheezing. PATIENTS AND METHODS: A total of 302 newborns were recruited. A nasopharyngeal aspirate was taken when the patients had a respiratory infection, as well as in the visits for vaccination at 2, 4, 6, and 12 months. RT-nested PCR assays were performed to detect 16 viruses. RESULTS: A total of 1,293 samples were analysed (1,005 healthy controls and 288 respiratory infections). Samples taken during routine check-ups were positive in 30.8% of cases, while those with respiratory infection were positive in 77.8%, P<.001 (OR: 3, 95% CI: 2.4-3.8). A total of 239 (79%) infants had at least 1 positive respiratory viral infection detected. The most frequent virus (71%) was rhinovirus (RV). Recurrent wheezing was found in 27 (11%) children during their first year of life (1.2 episodes, SD 2.9). Recurrent wheezing was present in 58.3% of patients admitted to hospital during their first viral infection, vs. 8.6% of infants when the first infection was mild or who had asymptomatic viral detection, P<.001 (OR: 2.18; 95% CI: 1.05-4.5). CONCLUSIONS: In our series, severe respiratory infections leading to hospitalisation in the first months of life are risk factors for developing wheezing, but not in the case of mild RV infections.

The potential use of Piptatherum miliaceum for the phytomanagement of mine tailings in semiarid areas: Role of soil fertility and plant competition.

Phytomanagement in terms of phytostabilisation has been proposed as a suitable technique to decrease the environmental risks of metal(loid) enriched mine tailings. Nevertheless, at these sites some issues must be solved to assure the long-term establishment of vegetation (e.g. salinity, low fertility, metal(loid) phytotoxicity, etc.) The objective of this study was to assess the effects of the addition of a municipal solid waste on a mine tailings soil and on the growth and metal(loid) accumulation of a grass plant species (Piptatherum miliaceum). In addition, the effects of intra-specific interactions were evaluated. A pot experiment was performed during 8 months, including two soil treatments: the mine soil and its combination with municipal solid wastes. For each treatment, pots without plants, pots with one plant, and pots with two plants were arranged. The addition of municipal solid wastes improved the soil fertility and plant growth in the mine soil, but also increased the mobile fractions of Zn, Pb, Cd, Mn and Ni. Plants in the amended treatments showed better nutritional status (higher P and K). Stable isotope δ(15)N was associated to the better nutritional status, while δ(13)C and δ(18)O indicated higher photosynthetic efficiency and stomatal conductance in amended treatments. Although the accumulation in leaves of most metal(loid)s decreased with the municipal waste application, the concentrations in both treatments did not exceed toxic limits for fodder. There was an effect of intra-specific competition in plant growth, probably due to lack of nutrients in the mining soil or limited pots volume in the treatments with municipal waste.

Metal(loid) allocation and nutrient retranslocation in Pinus halepensis trees growing on semiarid mine tailings.

The goal of this study was to evaluate internal metal(loid) cycling and the risk of metal(loid) accumulation in litter from Pinus halepensis trees growing at a mine tailing disposal site in semiarid Southeast Spain. Internal nutrient retranslocation was also evaluated in order to gain insight into the ability of pine trees to cope with the low-fertility soil conditions at the tailings. We measured metal(loid) concentrations in the foliage (young and old needles), woody stems and fresh leaf litter of pine trees growing on tailings. The nutrient status and stable isotope composition of pine foliage (δ(13)C, δ(15)N, δ(18)O as indicators of photosynthesis and water use efficiency) were also analyzed. Tailing soil properties in vegetation patches and in adjacent bare soil patches were characterized as well. Significant amounts of metal(loid)s such us Cd, Cu, Pb and Sb were immobilized in the woody stems of Pinus halepensis trees growing on tailings. Leaf litterfall showed high concentrations of As, Cd, Sb, Pb and Zn, which thereby return to the soil. However, water extractable metal(loid) concentrations in tailing soils were similar between vegetation patches (mineral soil under the litter layer) and bare soil patches. The pines growing on mine tailings showed very low foliar P concentrations in all leaf age classes, which suggests severe P deficiency. Young (current year) needles showed lower accumulation of metal(loid)s, higher nutrient concentrations (P and K), and higher water use efficiency (as indicated by and δ(13)C and δ(18)O data) than older needles. Substantial nutrient resorption occurred before leaf litterfall, with 46% retranslocation efficiency for P and 89% for K. In conclusion, phytostabilization of semiarid mine tailings with Pinus halepensis is feasible but would require careful monitoring of the trace elements released from litterfall, in order to assess the long term risk of metal(loid) transfer to the food chain.

Usefulness of pioneer vegetation for the phytomanagement of metal(loid)s enriched tailings: grasses vs. shrubs vs. trees.

The goal of this work was to assess the selection of the most suitable combination of plant species for the phytomanagement of mine tailings, by comparing among different plant life-forms (grasses, shrubs and trees). A comparison on induced rhizosphere changes generated by four plant species (the grass Piptatherum miliaceum, the shrub Helichrysum decumbens, and the trees, Pinus halepensis and Tetraclinis articulata) and high density vegetation patches (fertility islands) at a mine tailing located at Southeast Spain and the description of their physiological status employing stable isotopes analyses were carried out. The edaphic niches for plant growth were determined by salinity, organic matter and total soil nitrogen while metal(loid)s concentrations played a minor role. Induced changes in plant rhizospheres had a significant impact in soil microbiology. While grasses and shrubs may play an important role in primary ecological succession, trees seem to be the key to the development of fertility islands. The low δ(15)N values (-8.00‰) in P. halepensis needles may reflect higher ectomycorrhizal dependence. Large differences in leaf δ(18)O among the plant species indicated contrasting and complementary water acquisition strategies. Leaf δ(13)C values (-27.6‰) suggested that T. articulata had higher water use efficiency than the rest of species (-29.9‰). The implement of a diverse set of plant species with contrasting life forms for revegetating tailings may result in a more efficient employment of water resources and a higher biodiversity not only in relation to flora but soil microbiology too.

The importance of edaphic niches and pioneer plant species succession for the phytomanagement of mine tailings.

Phytomanagement in terms of phytostabilisation is considered a suitable method to decrease environmental risks of metal(loid) enriched mine tailings. The goal of this study was to identify plant-favourable edaphic niches in mine tailings from a semiarid area, in order to obtain relevant information for further phytostabilisation procedures. For this purpose, a transect-designed sampling from non-disturbed soils to two mine tailings was performed, including the description of soil and plant ecology gradients. Plant ecological indicators showed several stages in plant succession: from weeds to stable patches of late successional plant species. PCA results revealed that plant distribution at the tailings was driven mainly by salinity while metal(loid) concentrations played a minor role. The presence of soil desiccation cracks generated low salinity patches which facilitated favourable niches for plant establishment. Edaphic-patch distribution may condition phytostabilisation since ploughing or the employment of certain amendments should take into account favourable niches for plant growth.