Enzyme activity indicates soil functionality affectation with low levels of trace elements.

The use of the soil can alter its functionality and influence the (bio)availability of any contaminants present. Our study considers two types of agricultural soils, rainfed and olive soils, managed according to conventional practices that apply contaminants directly to the soil (fertilizers, pesticides, fungicides, etc.) and receive contaminants from the atmosphere (traffic, industry, etc.); and a forest soil that is not subject to these agricultural practices. In this scenario, we consider a mixture of 16 trace elements (As, Ba, Be, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Se, Sb, Sn, V and Zn), since their interactions with the soil can produce synergistic and/or antagonistic effects that are not considered in most studies. We studied whether the content and (bio)availability of low concentrations of a mixture of trace elements affect the soil functionality in terms of the activity of some key enzymes We analysed the total, potentially and immediately available fractions, the soil parameters and soil enzyme activity. The results show that the functionality of the soils studied was affected despite the low concentrations of trace elements. The highest concentrations of total trace elements and available fractions were found in forest soils compared to the other two uses. Soil enzyme activity is best explained by the potentially available fraction of a mixture of trace elements and physico-chemical soil variables. In our study, pH, total nitrogen, organic carbon and fine mineral particles (silt and clay) had an influence on soil enzyme activity and the (bio)available fractions of trace elements.

Estudio de los suelos del entorno del Balneario de San Nicolás (Almería) / Study soil in the thermal environment of San Nicolás (Almería)

Las propiedades fisico‐químicas de los suelos que se encuentran en la parte superficial de las capas freáticas, juegan un papel muy importante en las características hidroquímicas de las aguas subyacentes, pues fenómenos como disolución, hidrolisis y procesos de oxido‐reducción de fracciones minerales y orgánicas de los suelos influyen de forma significativa en la composición de las mismas. Además, textura, estructura y materia orgánica del suelo son factores claves en la regulación del régimen hidrodinámico. En este trabajo analizamos las características edáficas de cuatro suelos muy significativos de los alrededores del Balneario de San Nicolás, ubicado en Alhama de Almería, Alpujarra Almeriense, situada a 450 msnm en la ladera norte de la Sierra de Gádor. Son suelos con escaso desarrollo, tipo AC, formados a partir de materiales sedimentarios constituidos por margas arenosas, calcarenitas, dolomías y yeso, los situados en las proximidades del Valle del Andarax, y por materiales de derrubios de ladera y pie de monte, con predominio de cuarcita, dolomías, calizas y calizas margosas, los situados en la Sierra de Gádor. Los suelos son carbonatados y están saturados, siendo el calcio el catión mayoritario. Presentan pHs básicos, bajo contenido en materia orgánica y texturas gruesas. Cuarzo, calcita, dolomita y yeso son los minerales más abundantes entre los no laminares, y son las micas los filosilicatos presentes en mayor proporción. El predominio de texturas gruesas y la perdida de estructura en los horizontes profundos son determinantes en el grado de infiltración. Se han incluido en las unidades Regosoles y Calcisoles (AU)

The physico‐chemical properties of soils adjacent to aquifers play an essential role in the hydrochemical characteristics of the underlying waters. Thus, phenomena such as dissolution, hydrolysis and oxide‐reduction processes of the mineral and organic fractions of soils may have a significant influence on the composition of these waters. Furthermore, soil texture, structure and organic matter are key factors regulating the hydrodynamic regime. In this work, the edaphic characteristics of four highly representative soils located in the thermal environment of San Nicolas in the Alhama de Almería municipality of the Alpujarra Almeriense region were analyzed. The area is part of the northern side of the Sierra de Gádor at an altitude of 450 masl. They are poorly developed soils, mainly AC profiles. Soils in the vicinity of the Andarax Valley are formed on sedimentary materials constituted by sandy marls, calcarenites, dolomites and gypsum, and those in the Sierra de Gádor developed on debris material from hillside and piedmont and mainly integrated by quartzite, dolomites, limestones and marly limestones. Soils are carbonated and saturated, with calcium being the major cation. They have basic pH values, low organic matter content and coarse textures. Quartz, calcite, dolomite and gypsum are the prominent minerals among the non‐laminar ones, and micas among the phyllosilicates. The predominance of coarse textures and the loss of structure in the deep horizons are decisive in their infiltration capacity. They were classified as Regosols and Calcisols (AU)

Impact of vineyard abandonment and natural recolonization on metal content and availability in Mediterranean soils.

Abandonment of vineyards after uprooting has dramatically increased in last decades in Mediterranean countries, often followed by vegetation expansion processes. Inadequate management strategies can have negative consequences on soil quality. We studied how the age and type of vegetation cover and several environmental characteristics (lithology, soil properties, vineyard slope and so on) after vineyard uprooting and abandonment contribute to the variation patterns in total, HAc (acetic acid-method, HAc) and EDTA-extractable (ethylenediaminetetraacetic acid-method) concentrations of Cd, Cu, Pb and Zn in soils. We sampled 141 points from vineyards and abandoned vineyard Mediterranean soils recolonized by natural vegetation in recent decades. The contribution of several environmental variables (e.g. age and type of vegetation cover, lithology, soil properties and vineyard slope) to the total and extractable concentrations of metals was evaluated by canonical ordination based on redundancy analysis, considering the interaction between both environmental and response variables. The ranges of total metal contents were: 0.01-0.15 (Cd), 2.6-34 (Cu), 6.6-30 (Pb), and 29-92mgkg(-1) (Zn). Cadmium (11-100%) had the highest relative extractability with both extractants, and Zn and Pb the lowest. The total and EDTA-extractable of Cd, Pb and Zn were positively related to the age of abandonment, to the presence of Agrostis castellana and Retama sphaerocarpa, and to the contents of Fe-oxides, clay and organic matter (OM). A different pattern was noted for Cu, positively related to vineyard soils. Soil properties successfully explained HAc-extractable Cd, Cu, Pb and Zn but the age and type of vegetation cover lost significance. Clay content was negatively related to HAc-extractable Cu and Pb; and OM was positively related to HAc-Cd and Zn. In conclusion, the time elapsed after vineyard uprooting, and subsequent land abandonment, affects the soil content and availability of metals, and this impact depended on the colonizing plant species and soil properties.

Estudio de los suelos de los alrededores del Balneario de Villavieja de Nules (Castellón de la Plana) / Study soil around the spa in Villavieja de Nules (Castellón de la Plana)

El suelo es la primera barrera natural que han de atravesar los compuestos depositados en la superficie terrestre para llegar a los acuíferos. Conocer las propiedades fisicoquímicas que intervienen en los procesos de infiltración, así como saber el tipo de suelo, son parámetros esenciales que nos permite analizar el riesgo de contaminación que afecta la composición del agua subterránea. En este trabajo se describen los factores ambientales de la zona, y se analizan algunas de las propiedades químicas, físicas y mineralógicas de cuatro suelos característicos de los alrededores del Balneario de Villavieja de Nules (Castellón de la Plana). Para ello se ha obtenido el contenido en: C, N, pH, CE, CIC y CO3 2‐ , así como se ha determinado: textura, densidad aparente, densidad real, porosidad, parámetros hidráulicos y la mineralogía de la fracción arcilla. De los resultados se desprende que las características ambientales de la zona, junto a los tipos de suelos analizados ralentizan los procesos de flujos descendentes (AU)

Soil i s the first natural barrier that has to be crossed by the compounds deposited on the Earth's surface to reach aquifers. Knowing about the physicochemical properties involved in the infiltration processes, as well as the soil type, are essential parameters which allows us to analyze the risk of contamination affecting the composition of groundwater. In this work, the environmental factors of the area around the Balneario de Villavieja Nules (Castellón de la Plana) are described, and some of the chemical, physical, and mineralogical characteristics of four soils are analyzed. Most particularly C, N, pH, CE, CIC y CO3 2‐ , as well as texture, bulk density, particle density, porosity, hydraulic parameters and clay fraction mineralogy were determined. The results showed that the environmental characteristics of the area, together with the types of soil analyzed slow down the water flow processes (AU)

Suelos del entorno del balneario / Soils in the thermal environment of "Villa de Olmedo" (Valladolid)

El conocimiento del suelo es imprescindible para comprender el riesgo de la posible afectación de las aguas subterráneas, especialmente en áreas sometidas a una fuerte presión de actividad agrícola. Se presenta el estudio de tres suelos localizados en los alrededores del Balneario "Villa de Olmedo", provincia de Valladolid. Se han desarrollado a partir de arcosas, situados en topografía llana, con una altitud entorno a los 750 m y bajo clima Mediterráneo templado. Se analizaron las propiedades morfológicas, físicas, químicas y mineralógicas de los suelos. En general, son suelos poco evolucionados, con textura gruesa, pH próximos a la neutralidad y horizontes superficiales con características ántricas

Soil characteristics are decisive in groundwater quality. The impact of human activities, especially in areas subject to agricultural pressure, involves potential risks which may be critical to the viability of the water resource. This work gathers together the study of three representative soils located in the thermal environment of "Villa Olmedo", Valladolid. All of them have developed from arkoses and found around 750 m elevation in a zone of flat topography. Morphological, physical, chemical and mineralogical properties of these soils were analyzed. They are poorly developed, coarse textured, with pH close to neutrality and antric features in the surface horizons

Biological activity in metal-contaminated calcareous agricultural soils: the role of the organic matter composition and the particle size distribution.

Organic matter (OM) plays a key role in microbial response to soil metal contamination, yet little is known about how the composition of the OM affects this response in Mediterranean calcareous agricultural soils. A set of Mediterranean soils, with different contents and compositions of OM and carbonate and fine mineral fractions, was spiked with a mixture of Cd, Cu, Pb, and Zn and incubated for 12 months for aging. Microbial (Biolog Ecoplates) and enzyme activities (dehydrogenase, DHA; ß-galactosidase, BGAL; phosphatase, PHOS; and urease, URE) were assessed and related to metal availability and soil physicochemical parameters. All enzyme activities decreased significantly with metal contamination: 36-68 % (DHA), 24-85 % (BGAL), 22-72 % (PHOS), and 14-84 % (URE) inhibitions. Similarly, catabolic activity was negatively affected, especially phenol catabolism (∼86 % compared to 25-55 % inhibition for the rest of the substrates). Catabolic and DHA activities were negatively correlated with ethylenediaminetetraacetic acid (EDTA)-extractable Cd and Pb, but positively with CaCl2, NaNO3, and DTPA-extractable Cu and Zn. Soluble OM (water- and hot-water-soluble organic C) was positively related to enzyme and catabolic activities. Recalcitrant OM and fine mineral fractions were positively related to BGAL and PHOS. Conversely, catabolic activity was negatively related to clay and positively to silt and labile OM. Results indicate that the microbial response to metal contamination is highly affected by texture and OM composition.

Metal extractability patterns to evaluate (potentially) mobile fractions in periurban calcareous agricultural soils in the Mediterranean area-analytical and mineralogical approaches.

A set of periurban calcareous agricultural Mediterranean soils was spiked with a mixture of Cd, Cu, Pb and Zn at two levels within the limit values proposed by current European legislation, incubated for up to 12 months, and subjected to various one-step extraction procedures to estimate mobile (neutral salts) and potentially mobile metal fractions (complexing and acidic extraction methods). The results obtained were used to study metal extractability patterns according to the soil characteristics. The analytical data were coupled with mineralogical investigations and speciation modelling using the Visual Minteq model. The formation of soluble metal-complexes in the complexing extracts (predicted by the Visual Minteq calculations) led to the highest extraction efficiency with complexing extractants. Metal extractability patterns were related to both content and composition of carbonate, organic matter, Fe oxide and clay fractions. Potentially mobile metal fractions were mainly affected by the finest soil fractions (recalcitrant organic matter, active lime and clay minerals). In the case of Pb, scarce correlations between extractable Pb and soil constituents were obtained which was attributed to high Pb retention due to the formation of 4PbCO3·3PbO (corroborated by X-ray diffraction). In summary, the high metal proportion extracted with complexing agents highlighted the high but finite capacity to store potentially mobilizable metals and the possible vulnerability of these soils against environmental impact from metal accumulation.

El suelo en la biosfera y su repercusion en la Salud Ambiental / Soil in the biosphere and its impact on Environmental Health

Se analiza en este trabajo el papel que juega el suelo en el desarrollo de los ecosistemas terrestres y su influencia en la salud ambiental. No siempre que se han estudiado los factores que intervienen en la evolución del medioambiente se ha tenido en cuenta la edafosfera como el sistema donde agua, aire, materia orgánica y materia mineral se entremezclan para formar la epidermis del planeta. Tratamos, a partir de entender el suelo como un sistema sin el cual la vida no existiría, de encontrar algunas respuestas que ayuden a los indicadores ambientales a detectar los procesos que tienen lugar en la naturaleza. El crecimiento de la población y la aceleración del desarrollo están llevando a una situación en la que no se podrá aplicar el concepto de .sostenibilidad.. Estudiar el suelo para entender su funcionamiento y su relación con la salud de los habitantes es un reto que debe ser asumido con urgencia por los científicos que estudian el suelo (AU)

In this work, we examine the role of soil in the development of terrestrial ecosystems and its influence on environmental health. Not all studies on the factors involved in environmental evolution have considered the edaphosphere as the system where water, air, organic matter and minerals blend to form our planet's skin. By dealing with soil as a system without which no life could ever exist, we aim to find some answers that may help environmental indicators identify natural processes. Population growth and the in- creasingly accelerated development are leading to a situation where the ìsustainabilityî concept may no longer be applicable. Studying soil with a view to understanding the way it acts and how it relates to human health is a challenge to be urgently met by all soil scientists (AU)

Estudio de la influencia de los suelos contaminados por metales pesados en las aguas naturales / Influence of polluted soils by heavy metals on natural water

En este trabajo se estudia las características de los lixiviados procedentes de suelos carbonatados, que han sido sometidos a un proceso de desplazamiento usando un sistema experimental de columnas. Las características químicas de la solución efluente ponen de manifiesto que, la mineralización de las muestras se debe, principalmente, a la disolución de minerales carbonatados. No obstante, es de resaltar la contribución que tiene los procesos de hidrólisis de minerales silicatados.Identificada la solución, se procedió a los ensayos de contaminación utilizando una mezcla de metales pesados, todos ellos con igual concentración, observándose que los porcentajes de absorción fueron superiores al 90 por ciento, siendo el Cr y el Cu los cationes más retenidos y el Cd el catión más móvil. A continuación se sometieron los suelos a cuatro procesos de lavado sucesivos, apreciándose una secuencia de retención en suelo de: Cr>Cu>Pb"Zn"Ni>Cd. Esta secuencia permite reconocer que Cr, Cu y Pb son los cationes de metales pesados más fuertemente adsorbidos en situación de competencia, y es el Cd el catión que presenta mayor índice de peligrosidad, tanto por su naturaleza tóxica como por su movilidad (AU)