Assessment of trace element phytoavailability in compost amended soils using different methodologies

Purpose

This study evaluates the effects of two soil amendments and the growth of two plant species on labile trace element (TE) fractions in two different contaminated soils.

Materials and methods

We studied the effects of two organic amendments (biosolid compost and alperujo compost) and two plant species (Medicago polymorpha and Poa annua) on pH, total organic carbon (TOC), and TE availability, by three extraction methods (CaCl₂ aqueous solution, soil pore water (SPW), and diffusive gradient in thin film (DGT)), in two contaminated soils with contrasting pH values (Aznalcázar, 6.53, and Vicario, 3.48) in a 118-day pot experiment. The effects of the composts on labile TE fractions were compared with element concentrations in plants.

Results and discussion

No relevant effects of amendments and plants were found on the physical and chemical characteristics of the Aznalcázar soil. However, the addition of amendments was essential for plant species growing in the acid Vicario soil. In this soil, amendments and plant growth increased pH and TOC and reduced substantially TE bioavailability. Although absolute values of bioavailable TE contents obtained by the three methods were very different and followed the trend CaCl₂ extraction?>?SPW?>?DGT, these values follow a similar behavior in the two studied soils and for the two species.

Conclusions

The results demonstrate that the application of organic amendments are suitable for remediating acid TE-contaminated soils, for the establishment of a vegetation cover on previously bare soils for reducing wind and water erosion and for reducing labile TE fractions to prevent leaching of pollutants into subsoil or groundwater layers. Moreover, the results obtained in this study pointed out that under microcosm conditions, the three methods tested (CaCl₂ extraction, SPW, and DGT) to predict TE bioavailability were highly correlated.

     

Effect of soil cadmium concentration on three Chilean durum wheat cultivars in four environments

Durum wheat (Triticum turgidum L. var durum) is a species that accumulates cadmium (Cd). Durum wheat cultivars differ in their absorption ability of Cd; therefore, identifying and selecting genetic material with low Cd accumulation reduces human exposure to this toxic element. In the present study, Cd concentration was evaluated in three Chilean durum wheat cultivars (Llareta-INIA, Corcolén-INIA, and Lleuque-INIA) grown in four Chilean locations with varying concentrations of Cd in soils. The objective of this study was to evaluate the response of these durum wheat cultivars to different doses of cadmium in terms of grain yield; Cd concentration in different plant tissues (grain, straw, roots); soil Cd concentration was also evaluated. Results show that grain yield was not affected by soil Cd; differences in Cd concentration in plant tissues were generally associated with location, cultivar, and soil Cd concentration. Grain Cd concentration in all three cultivars was classified in the low accumulation category for this metal; ‘Lleuque-INIA’ noted as having a very low accumulation.     

Hemolytic-uremic syndrome in a dog

A 3-year-old, spayed, female Boxer was presented because of acute onset of anorexia, vomiting, and hemorrhagic diarrhea. Microangiopathic hemolytic anemia with intravascular hemolysis, thrombocytopenia, and acute renal failure were detected. The dog was treated with fluids, antiemetics, antibiotics, and diuretics. Despite supportive therapy, the dog's condition worsened, and the owners elected euthanasia. Necropsy revealed disseminated petechiae on the parietal peritoneum and serosal surfaces of the intestinal tract. The histologic lesions were consistent with severe arteritis and microvascular thrombosis involving only the renal and intestinal arterioles. The final diagnosis was hemolytic-uremic syndrome (HUS), a rarely described disorder in dogs. The clinical presentation of primarily gastrointestinal clinical signs was similar to that of typical or diarrhea-associated HUS (D+ HUS) in humans (mainly children), which is caused by gastrointestinal proliferation of verocytotoxin-producing Escherichia coli. Bacterial toxins can be adsorbed and cause endothelial injury, activation of hemostasis, and thrombosis, with lesions confined primarily to the kidneys. Although rare, HUS should be considered in the differential diagnosis of dogs with microangiopathic hemolytic anemia.     

Appearance of multinucleated giant cells in association with an adenovirus infection in two guinea pigs

In two guinea pigs (five years old, neutered male, and two and a half months old male, respectively) suffering from interstitial pneumonia, multinucleated giant cells were observed histologically in lungs, spleen and liver. The giant cells showed intranuclear, pale basophilic inclusions. Adenovirus could be demonstrated by electron microscopy.The multinucleated cells are supposed to be of histiocytic origin, since they contained variable amounts of haemosiderin in their cytoplasm. Formation of histiocyte-derived syncytia as a result of virus-induced cell fusion is discussed.     

Seroprevalence of and risk factors for Toxoplasma gondii in sheep raised in the Jaboticabal microregion, São Paulo State, Brazil

Seroprevalence of and risk factors for toxoplasmosis in sheep from different properties in the Jaboticabal microregion, São Paulo State, Brazil were determined. Antibodies to Toxoplasma gondii were found in sera of 52.0% of 488 sheep tested by indirect fluorescent antibody test (IFAT ? 64). T. gondii seropositivity in sheep was significantly associated with gender of the sheep, pasturing system, contact with cats, and the use of mineral supplements and the type of feed.     

Growth of Mature Beech in Relation to Ozone and Nitrogen Deposition: an Epidemiological Approach

Stem increment of mature Fagus sylvatica L. from 57 plots in Switzerland was analysed with respect to environmental factors using multilinear regression. Nitrogen (N) deposition was positively correlated with stem growth, with an increase by 41.8% (confidence interval 38.9-44.2) per 10 kg N ha^-1 a^-1. There was a negative relationship between ozone (O₃) dose and diameter increment. The fit was better for maximum rather than average exposure values. Coefficients indicated growth changes of -22.5% (14.3-28.6 confidence interval) and -35.1% (17.8-47.3) respectively per 10 ppm hours. These changes exceed the -6.1% found in experiments with beech seedlings. This difference is mainly attributed to the fact that the seedling data are calculated for a single season's exposure whereas the stem increment data extend over four years, representing the product of four annual reductions. Increased sensitivity of mature trees compared to seedlings, however, is also suggested.