Jovana Bavaresco

Attic dust assessment near a wood treatment plant: Past air pollution and potential exposure

The wood treatment process uses substances that generate hazardous compounds that may contaminate environmental compartments. In the present study, an area under influence of a deactivated wood treatment plant was investigated to evaluate past air pollution and to try to understand local air dispersion. Attic dust samples were collected from eight residences around the plant and from two residences outside this area, as reference samples. The presence of copper, chromium, arsenic, pentachlorophenol, sixteen priority polycyclic aromatic hydrocarbons and mutagenic activity using Salmonella/microsome assay was evaluated. The residences close to the entrance to the plant were the most affected, according to potentially toxic elements analysis. The PCP concentration was 0.49 mg/kg and the total PAHs content ranged from 0.40 to 13.31 μg/g with greater dispersion than potentially toxic elements. The highest mutagenesis values were 15,905 and 10,399 revertants/g of dust in the absence and presence of S9 mix (mammalian metabolic activation), respectively. Samples in which the total PAHs concentration was less than 2 μg/g no mutagenic effects were observed, including the residences in the reference area. The contribution of PAHs to mutagenesis was 10 percent, indicating that other compounds may contribute to the mutagenic effect. These results suggest that the population was or is potentially exposed to substances with strong effects on health.

Diffusion and uptake of phosphorus, and root development of corn seedlings, in three contrasting subtropical soils under conventional tillage or no-tillage

Soil mineralogy and management can have substantial effects on phosphorus (P) diffusion in soil and hence on root morphology. The aim of this study was to assess these effects in soils differing widely in P-sorbing components. Samples of a Rhodic Paleudult (RP), a Rhodic Hapludox (RH), and a Humic Hapludox (HH) under conventional tillage (CT) or no-tillage (NT) were placed in Petri dishes to assess P diffusion. Performance and root morphology in corn grown on soil samples subjected to three different P fertilization treatments (no fertilizer, surface, and deep fertilizer application) were examined. Phosphorus diffusion was slower in the HH than in the other soils by effect of its high P adsorption capacity because of its mineralogy. Soil management had no effect on P diffusion. Fertilization with P only affected plant-related variables in RH: surface fertilization increased root biomass, and deep fertilization shoot biomass and proportion of thick roots. Soil management affected plants growing on HH and RP: the plants grown under NT were taller (RP) and developed more fine roots (HH) than those under CT. Fertilization with P had little effect on plant growth in the goethite-rich soil (HH) or the one with high content in available P (RP). Our results suggest that management system in these soils has therefore greater influence on fertility than fertilization treatment.

A screening method for detection of hexavalent chromium levels in soils

-1 was used throughout. For the different types of soils studied, more than 75% of the fortified soluble Cr(VI) were recovered for all levels of spike tested for both the proposed and standard methods. Recoveries of 83 and 99% were obtained for the proposed and the standard methods, respectively, taking into account the analysis of a heavily contaminated soil sample.

Chromium Adsorption in Different Mineralogical Fractions from Subtropical Soils

Abstract Safe application of chromium (Cr)–containing organic industrial wastes to soil requires considering the ability of the soil to adsorb Cr. In this study, the maximum Cr adsorption capacity was assessed for the bulk samples and their clay and iron–free clay fractions of four subtropical soils differing in mineralogy. To this end, the samples were supplied with Cr(III) nitrate solutions at pH 4.5 or 5.5. The results of Cr(III) adsorption fitted to a Freundlich equation and the adsorption capacity was positively correlated with soil organic matter and iron oxide contents. The clay fractions adsorbed more Cr per unit mass than the bulk soils and the iron–free clay fractions. The Cr(III) adsorption capacity increased with increasing soil pH due to more charges on adsorbing surfaces. Our results suggest that the soils rich in organic matter and iron oxides and having a pH above 4.5 are suitable for application of Cr(III)–loaded industrial wastes.

Chromium from Hydrolyzed Leather Affect Soybean Growth and Nodulation

Abstract Hydrolyzed leather, obtained from industrial leather waste, is an organic nitrogenous fertilizer with a high chromium (Cr) content. Soybean crops can be adversely affected by the presence of residual Cr in soil after application of hydrolyzed leather fertilizer. The aim of this work was to assess the effect of hydrolyzed leather on Cr absorption, root development, and symbiotic nodulation of soybean plants grown on three different soils including two Lixisols and a Gleysol. These soils were previously fertilized with hydrolyzed leather at three different rates (0.0, 0.1, and 0.8 kg m−2). Soybean shoot height, root development, nodulation, and mineral nutrient concentrations in plant tissues were determined after 45 d of crop growth. The application of hydrolyzed leather significantly increased Cr content in soil and Cr uptake by plants. Surprisingly, Cr was stored mainly in the aerial part of the plants. The presence of Cr had an adverse impact on shoot dry matter (41% reduction) and number of nodules (49% reduction) per plant grown on the soil with the lowest cation exchange capacity. However, no other significant effect was observed in nodule weight, diameter, or any other measured parameters.