Accumulation, distribution pattern and potential contamination of sulphur in vineyard soils of the Valdepeñas protected denomination origin.

Soil is the basis for almost all global agriculture and the medium in which most terrestrial biological activity occurs. Viticulture represents an important agricultural practice in the Castilla-La Mancha (CLM) community. In this region, there are several protected denominations of origin (PDO), the largest being Valdepeñas. This paper describes the accumulation pattern of sulphur (S) in the vineyard soils of this PDO. Samples were collected from 90 vineyard soil profiles. Sulphur content was determined using an X-ray Fluorescence spectrometer in the solid mode on a powdered aliquot of each sample. The results indicated that the total S in soils varied from 0.54 to 6.90 (g·kg-1) in surface soil (0-30 cm) and from 0.39 to 2.80 (g·kg-1) on the subsurface layer (30-80 cm). When comparing the mean values of surface horizons to the subsurface horizons, S content lowered as soil depth increased. Kurtosis exceeded 45 % in all cases, which indicates a wide variability of concentrations. These findings can be explained by the continuous fertiliser and fungicide applications (and therefore S) in these production systems. Using the geoaccumulation index (Igeo), most soils were included in Class 0 (Igeo <0) and were, thus, S uncontaminated; only a few points can be considered pollutants. The obtained results should contribute to extend the scarce existing database on S in Mediterranean regions like that herein studied.

Environmental assessment of potential toxic trace element contents in the inundated floodplain area of Tablas de Daimiel wetland (Spain).

Contamination of aquatic systems with potentially toxic trace elements (PTEs) is a major problem throughout the world. The National Park Tablas de Daimiel (NPTD) is considered to make up one of the two most important wetlands in the Biosphere Reserve called "Wet Spot." Since PTEs are good indicator of the prevailing environmental conditions and possible contamination, soil samples collected from 43 sites were analyzed in order to investigate the levels and its distribution of these elements, in the inundated floodplain area of the NPTD wetland. In addition, some physicochemical parameters such as pH, electrical conductivity and organic matter were measured. The total concentrations of 32 trace elements were determined by X-ray fluorescence. The results show that there was accumulation of lead (Pb), tin (Sn), selenium (Se), antimony (Sb), copper (Cu), vanadium (V), nickel (Ni), zinc (Zn), arsenic (As), strontium (Sr) and zirconium (Zr)-in some cases at high concentrations. The interpolated maps showed that the distributions of some of these elements and in some cases the trend in spatial variability are pronounced and decrease from the inlet to the outlet. The values for some elements are higher than the reference values, which is consistent with contamination (some values are higher by a factor of more than 10 compared to the reference). In the case of iodine (I), the levels at some sample points are significantly more than ten times the reference; Se appears in the range from 1.0 to 9.8 mg/kg, with an average value of 3.1 mg/kg, and these can be considered as seleniferous soils. The concentrations found are consistent with the introduction in the wetland of pollution by human activities, such as agricultural non-point sources, uncontrolled fertilization over many years, treatment with urban wastewater and other possible sources.

Spatial variability of cadmium and lead in natural soils of a humid Mediterranean environment: La Rioja, Spain.

The concentration levels of cadmium and lead in 250 horizon samples from 125 different soil profiles of undisturbed soils of La Rioja, Spain, were determined. Knowledge of regional contents as well as the variability and background values of trace elements in soils is of critical importance to assess human impact on the soil environment and to determine baseline values and quality standards. Heavy-metal horizontal distribution was mainly affected by the nature of the bedrock and, to a smaller extent, anthropogenic activity. Vertical distributions were mainly of a natural origin depending first on the bedrock and second on the result of soil processes.

Red soil geochemistry in a semiarid Mediterranean environment and its suitability for vineyards.

A geochemical study of a red soil derived from plioquaternary materials was carried out. The soil was located in a region of complex geomorphology and pedologic evolution, with particular characteristics of a Mediterranean climate associated with processes of alteration, rubification, gleying (hydromorphism) and argillization. The depth distribution of 27 trace elements was studied in order to determine the amounts of these elements in the soil and its tendency. The mineralogy of the clay fraction was also studied along with other physico-chemical properties to elucidate in terms of attributes meaningful for viticulture. The geochemical composition of the horizons was studied. The effect of human activities on the soil was investigated as well as the geographical origin of Mancha wines. It was found that these activities did not give rise to significant variations of trace elements, although a discontinuity related to the accumulation of new materials was detected. Ultimately, using established productivity standards, suitability for the cultivation of vines on these soils was determined.

Selenium distribution in topsoils and plants of a semi-arid Mediterranean environment.

Selenium was determined from 25 topsoils and 25 plants in the semi-arid Central Spain where large extents of soils are developed on evaporitic materials. Some species of vegetation associated with them are of the genera Astragalus, Salsola, Mercurialis, Phlomis, Thymus and Atriplex. Total selenium in soils was determined and its bioavailability assessed by chemical sequential fractionation. Se content in soils was adequate (in the range 0.17-0.39 mg kg(-1)) or large (in the range 0.50-4.38 mg kg(-1)) and appeared in highly and/or potentially available forms. Several plant species showed high Se levels (in the range 5-14.3 mg kg(-1)), which can be a potential risk of toxicity to animals. Data obtained from the study area can be used as a guide to the range of values in soils and plants of the European Mediterranean area that are relatively unpolluted from industrial sources, allowing comparison with more polluted areas.