Changes in Cd,Cu, Ni,Pb and Zn Fractionation and Liberation Due to Mussel Shell Amendment on a Mine Soil

Mining activities are related to relevant environmental pollution issues that should be controlled. We used sequential extractions to fractionate Cd, Cu, Ni, Pb and Zn retained on unamended or mussel shell‐amended mine soil samples, all of them treated with a mixture of the five heavy metals (total metal concentration of 1·57 mmol L⁻¹), after 1, 7 and 30 days of incubation. In addition, we used the stirred flow chamber technique to study the release of each of the five heavy metals from these different unamended and shell‐amended soil samples. The results indicate that the shell amendment caused a decrease in the most soluble fraction, while increasing the most recalcitrant (least mobile) fraction. With equivalent implications, the stirred flow chamber experiments showed that mussel shell amendment was associated to a decrease in heavy metal release and increased retention. The highest mussel shell dose and incubation time caused the most relevant changes in pH values and thus in metal retention, also indicating the importance of pH modifications in the mechanism of retention acting in the amended samples. In view of these results, the use of mussel shell amendment can be encouraged to increase heavy metal retention in acid mine soils, in order to minimise risks of environmental pollution. Copyright © 2016 John Wiley & Sons, Ltd.     

Influence of pH and soil copper on adsorption of metalaxyl and penconazole by the surface layer of vineyard soils

The upper horizons of old vineyard soils have substantial copper contents due to the traditional use of copper-based fungicides. Total copper levels in eight vineyard soils in the Rías Baixas area of Galicia (northwestern Spain) ranged from 60 to 560 mg kg(-1) (mean +/- SD = 206 +/- 170 mg kg(-1)). The adsorption of the fungicides metalaxyl (pK(a) = 1.41) and penconazole (pK(a) = 2.83) by these soils was determined using fungicide solutions of pH 2.5 and 5.5, and desorption of fungicide adsorbed at pH 5.5 was also determined. In all cases, Freundlich equations were fitted to the data with R (2) > 0.96. Penconazole was adsorbed and retained more strongly than metalaxyl, with K(F) values more than an order of magnitude greater. In the desorption experiments, both fungicides exhibited hysteresis. Soil copper content hardly affected the adsorption of metalaxyl, but K(F) values for adsorption of penconazole increased at a rate of about 0.1 mL(n) (microg of penconazole)(1-n) (microg of Cu)(-1), which is attributed to the formation of Cu(2+)-penconazole complexes with greater affinity for soil colloids than penconazole itself. Because the dependence of K(F) for penconazole adsorption on copper content was the same at both pH values, complex formation appears not to have been affected by the solubilization of 6-17% of soil copper at pH 2.5. A similar copper dependence, or lack of dependence, was observed when 100-1000 mg kg(-1) of copper was added as Cu(NO(3))(2).2H(2)O to the solutions from which the fungicides were adsorbed.     

Subtilase cytotoxin encoding genes are present in human, sheep and deer intimin-negative, Shiga toxin-producing Escherichia coli O128:H2

Shiga toxin-producing Escherichia coli (STEC) O128:H2 is recognised worldwide to be an important non-O157 STEC associated with human illness and in particular with causing haemolytic uraemic syndrome. This serotype is commonly isolated from sheep and is being increasingly isolated from deer. We determined the virulence profile and genetic relationships of one human, six sheep and five deer intimin-negative STEC O128:H2 strains isolated in Spain over a 7-year period. Our goals were to establish the presence of other virulence-associated factors, such as SubAB, in intimin-negative STEC O128:H2 strains involved in human disease and in that case, to determine if sheep and/or deer represent a reservoir of SubAB-positive STEC O128:H2. All the strains lacked the eae gene and carried subtilase cytotoxin (SubAB) encoding genes (subAB) and tia genes, but not saa gene, suggesting the presence of the recently identified new variant of SubAB, encoded on a putative pathogenicity island together with tia. We report for the first time the presence of subtilase cytotoxin encoding genes in intimin-negative STEC O128:H2 strains pathogenic for humans and how this finding might explain their clinical relevance despite neither carrying eae nor stx subtypes associated with severe clinical outcomes, but only stx1c and stx2b. Multilocus sequence typing analysis revealed that STEC O128:H2 strains from sheep and deer belong to the clonal lineage of STEC O128:H2 strains involved in diarrhoeal and haemorrhagic diseases in humans. Our results indicate that sheep and deer represent a reservoir of SubAB-positive STEC O128:H2 strains and thus a potential source of human infection.     

Phenolic compositions of grapes and wines from cultivar cabernet sauvignon produced in chile and their relationship to commercial value

The phenolic composition of wine depends on, among other factors, the grapes used to make it. In this sense, knowledge of the chemical composition of grapes and its association with the resulting wines is an important tool to determine if there is a relationship between the phenolic composition of grapes and the price that these wines obtain in the market. For this purpose, grape skins and seeds from the cultivar Cabernet Sauvignon from the central region of Chile, in 2009 and 2010 vintages from two ripening points, were subjected to chemical and phenolic analyses, as were the wines made from these grapes. Grapes and the corresponding wines from three retail price wine categories, U.S. $6-8, U.S. $28-30, and U.S. $150-160, were evaluated. No differences were found across the price categories in the chemical analysis of grapes. Berry skins and wines from the higher price categories presented a higher concentration only of total tannins, and the differences in their concentrations were only among the different fractions of proanthocyanidins in the skins, seeds, and wines; there were no differences in their proportions. A seasonal effect influenced the concentrations of certain compounds in grapes and led to a decrease in the concentration of total phenols, total tannins, and total anthocyanins between sampling dates as harvesting moved toward the common commercial grape harvest in Chilean viticulture.     

Recurrent selection for quantitative resistance to soil-borne diseases in beans in the Mixteca region, Mexico

Most of the bean breeding for disease resistance has been done considering it as a qualitative trait. This work reports on bean breeding for resistance as a quantitative trait. Recurrent mass selection was used in order to simultaneously increase the polygenically inherited resistance to all locally important bean pathogens but with emphasis on bean common mosaic virus (BCMV) and bacterial blight (BB) in the Mixteca Region, Mexico. Qualitative resistances against soil-borne diseases, induced mainly by facultative pathogens, possessing little parasitic specialization, are unlikely to occur, and although breeding against these kinds of diseases was not originally planned, it turned out to be part of collateral field screening. The accumulation of quantitative resistance against soil-borne diseases in advanced lines of this program is described and includes two field experiments, a cycle for seed augmentation in large plots and two greenhouse experiments. The majority of lines of the advanced breeding cycles produced consistently higher yields and higher survival rates, when compared with the original parents and commercial varieties. However, the regional land races still have higher survival rates but they have lower yields. Soil-borne diseases were present during all breeding cycles carried out under field conditions in the Mixteca Region. This work indicates that breeding for quantitative resistance involves all locally important pathogens. It is then feasible to accumulate high levels of quantitative resistance, in a relatively short time, even to these intermittently severe, soil-borne diseases that are otherwise so difficult to manage. This revised version was published online in July 2006 with corrections to the Cover Date.     

Introduction of exotic fish species and decline of native species in the lower Po basin,north‐eastern Italy

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Acidification of mixtures of granite powder and compost for reuse in plant production

We evaluated the utilization of granite powder—a residue of stone cutting and polishing resulting from its preparation for construction and ornamental use—in the preparation of nursery potting mixtures, within a general objective of waste recycling and reuse. Granite powder was blended with two composts of different origins and properties: one elaborated from the organic fraction of municipal solid waste (MSW), and another from pine bark. Since all materials presented pH values over 8, which are excessive for growing most vegetal species, the use of iron sulphate to acidify them has been assessed. Three doses of iron sulphate (14, 69, and 97 g kg^?1, equivalent to 0.1, 0.5, and 0.7 meq H⁺ g^?1) were added to the granitic powder and mixtures with 25 or 75% (v/v) of each compost, which were incubated in the laboratory during 30 days. Doses of iron sulphate above 0.1 meq H⁺ g^?1 resulted in excessive electrical conductivity (>2 dS m^?1) in all the samples, and too low pH values (<5) in most of them. The productivity of granite powder/compost mixtures acidified with 0.1 meq H⁺ g^?1 was tested in a greenhouse experiment with ryegrass, where it was observed that plant productivity increased with respect to a control commercial substrate based on peat, in particular when the MSW compost was employed. On the basis of the physicochemical properties of the mixtures and the results of the greenhouse experiment, the use of granite powder mixed with 75% of MSW compost (v/v), acidified with 14 g kg^?1 of iron sulphate (0.1 meq H⁺ g^?1) is recommended.