Composites Produced from Natural Rubber and Chrome-Tanned Leather Wastes: Evaluation of their In Vitro Toxicological Effects for Application in Footwear and Textile Industries

A new composite has been developed from natural rubber and chrome-tanned leather waste for use in footwear and textile industries. The contribution of this material to environmental quality and sustained development should be highligh because chrome tanned leather wastes, a major environmental problem, can be recycled. However, the safety of this new material for human use is questionable, as it is already well reported in the literature that chromium, particularly in its hexavalent oxidation state, can be genotoxic and carcinogenic to living beings. Thus, the aim of this study was to evaluate in vitro biocompatibility of this composite material for possible use in the footwear and textile industries, through cytotoxicity, cell adhesion, and genotoxicity tests. Inductively coupled plasma optical emission spectrometry (ICP-OES) was used to measure both concentrations of total and hexavalent chromium. Based on the findings, it was concluded that the composite exhibits low levels of cytotoxicity and genotoxicity, and possesses favorable properties for initial cell adhesion. Furthermore, it was verified that the composites released low concentrations of chromium and that the predominant species released would be trivalent chromium. The results of the present study open the possibility of the incorporation of solid residues of tanned leather into chromium without necessarily the chromium contained in these residues influences the toxicity and genotoxicity of this new material.     

Determination of toxic metals in leather by wavelength dispersive X-ray fluorescence (WDXRF) and inductively coupled plasma optical emission spectrometry (ICP OES) with emphasis on chromium

The tanning industry is one of the largest environmental polluters due to high generation waste in all production processes, but the tanning is particularly worrisome due to the use of significant amounts of chromium. Cr is an element potentially toxic to both health and the environment, depending on the concentration and the oxidation state. Cr(VI) can come in contact with human skin when using leather goods, which can cause allergies and dermatitis, besides being carcinogenic. Considering that approximately 90% of the world production of leather is performed with Cr salts, the determination of this element in leather is necessary to avoid exposure to the risks that the element can provide. The main goal of this study was the development of an alternative analytical method for the determination of Cr in leathers (ovine and bovine leather tanned with Cr and vegetable tannin) using wavelength dispersive X-ray fluorescence (WDXRF) for direct solid analysis. Besides performing analysis of the chemical composition and determination of Al, As, Ba, Ca, Cd, Cr, Cu, Fe, Mg, Ni, Pb, Sb, Sr, Ti, and Zn in leather by inductively coupled plasma optical emission spectrometry (ICP OES). Principal component analysis (PCA) was also used in the evaluation of the WDXRF and ICP OES data sets. WDXRF calibration models for Cr presented satisfactory figures of merit and the analysis of the leathers revealed an alarming concentration of total Cr in the samples reaching 21,353 mg kg^?1.     

Management of sludge from fish ponds at the edge of the Itaparica Reservoir (Brazil): an alternative to improve agricultural production

Sludge generated in intensively managed tilapia fingerling breeding ponds near the Itaparica Dam in the semi-arid Brazilian northeastern region was tested as a soil conditioner to produce lettuce in an effort to mitigate the present environmental impact of the deposition of this sludge, thereby giving it a productive destiny. A greenhouse experiment was performed by mixing the sludge with a Haplic Planosol topsoil, a characteristic soil of the region, so that the sludge corresponded to 0, 25, 50, 75, and 100% of the mixture (substrate). The experiment was set up as a randomized block design with five blocks, each with three pots (5-kg substrate per pot) of the five sludge proportion treatments. One lettuce plant was transplanted into each pot, maintained under greenhouse conditions, and harvested 35 days after transplanting. Sludge, soil, and the substrates were evaluated for nutrient concentration and physical characteristics. Green and dry weights, stem diameter, and nitrogen, phosphorus, and potassium concentrations in the aboveground parts of the lettuce plants were determined. Sludge incorporation into the substrate improved its chemical and physical characteristics. The lettuce plants grew best in the substrate with 75% sludge, increasing its biomass production by 50% and more than doubling its nitrogen uptake.     

Synthesis of grafted natural pozzolan with 3-aminopropyltriethoxysilane: preparation,characterization, and application for removal of Brilliant Green 1 and Reactive Black 5 from aqueous solutions

Environmental Science and Pollution Research - Natural pozzolan is an amorphous silicate-based material of volcanic origin. In this work, the natural pozzolan was modified by using...     

Biophysical and monetary quantification of ecosystem services in a mountain region: the case of avoided soil erosion

Environment, Development and Sustainability - Even though ecosystem services have a significant contribution to human well-being, their value is not always recognized. Despite difficulties, the...     

Removal of Hg2+ ions by adsorption using (TiO2@MnO2)-NPs nanocomposite

Journal of Material Cycles and Waste Management - Waste water contaminated with inorganic mercury is considered a serious environmental problem, mainly due to the hazardous effects this contaminant...     

Heavy metal contamination and physiological variability in the Brazilian mangrove crabs Ucides cordatus and Callinectes danae (Crustacea: Decapoda)

 Physiological studies were made on the crabs Ucides cordatus (L.) and Callinectes danae sampled from populations living in “polluted” mangroves on the southeast littoral of Brazil. Analysis of Cu, Cd, Zn, and Fe of sediments and crab tissues showed interspecific differences in tissue concentrations, and significantly higher levels of Cu, Cd, and Zn in “polluted” populations compared to “unpolluted” crabs living in uncontaminated mangrove in the same geographical area. Individuals of both species from the polluted site showed significantly greater capacities for regulating blood osmotic concentrations at low salinity (9‰). However, U. cordatus showed a reduced hypo-regulatory ability in 34‰S. Differences in ionoregulation were also seen. “Polluted”C. danae showed significantly higher Na/ K-ATPase levels in posterior gills compared to “unpolluted” crabs. Oxygen consumption rates (M˙ _O2) were elevated in U. cordatus, but depressed in C. danae from the “polluted” population. Individuals of both species from this site showed significantly lower O:N ratios, mainly because of an increased net efflux of ammonia. Adenylate energy charge (AEC) values of muscle and hepatopancreas in “unpolluted” and “polluted” populations of both species were not significantly different. These physiological differences are discussed in relation to the known acute physiological and metabolic effects of heavy metals in crustaceans, and interpretated in the light of possible adaptive changes following long-term exposure to contamination. Received: 6 August 1999 / Accepted: 22 June 2000     

Remote sensing of aquatic vegetation: theory and applications

Aquatic vegetation is an important component of wetland and coastal ecosystems, playing a key role in the ecological functions of these environments. Surveys of macrophyte communities are commonly hindered by logistic problems, and remote sensing represents a powerful alternative, allowing comprehensive assessment and monitoring. Also, many vegetation characteristics can be estimated from reflectance measurements, such as species composition, vegetation structure, biomass, and plant physiological parameters. However, proper use of these methods requires an understanding of the physical processes behind the interaction between electromagnetic radiation and vegetation, and remote sensing of aquatic plants have some particular difficulties that have to be properly addressed in order to obtain successful results. The present paper reviews the theoretical background and possible applications of remote sensing techniques to the study of aquatic vegetation.     

Genotoxic evaluation of different doses of inorganic lead (PbII) in Hoplias malabaricus

Different genetic biomarkers have been used to evaluate the pollution effects of mutagenic agents such as metals and also a great variety of chemicals delivered on the environment by human activities. This way, the aim of the present report was to evaluate the effects of inorganic lead in fishes through the frequency of piscine micronuclei and nuclear morphological alterations in peripheral cells, chromosomal aberration frequency and comet assays in blood and kidney cells. Specimens of Hoplias malabaricus received different doses of lead by intra-peritoneal injections at time of 96 h. There was not a significant difference between control and treated groups for the piscine micronucleus and chromosomal aberration assays. In the comet assays there was a significant difference between control and contaminated groups. However, a significant difference between the applied doses was not observed. The results obtained with the comet assays also show that blood presented a higher sensibility than the kidney tissue, possibly due to the acute contamination. Although the results showed the genotoxic potential of lead at the 21 and 63 microg Pb(2 + )/g doses for both tissues, the lowest dose is considered more appropriate for future bioassays.     

Use of neural networks for monitoring surface water quality changes in a neotropical urban stream

This paper reports the using of neural networks for water quality analysis in a tropical urban stream before (2002) and after sewerage building and the completion of point-source control-based sanitation program (2003). Mathematical modeling divided water quality data in two categories: (a) input of some in situ water quality variables (temperature, pH, O2 concentration, O2 saturation and electrical conductivity) and (b) water chemical composition (N-NO2(-); N-NO3(-); N-NH4(+) Total-N; P-PO4(3-); K+; Ca2+; Mg+2; Cu2+; Zn2+ and Fe+3) as the output from tested models. Stream water data come from fortnightly sampling in five points along the Ipanema stream (Southeast Brazil, Minas Gerais state) plus two points downstream and upstream Ipanema discharge into Doce River. Once the best models are consistent with variables behavior we suggest that neural networking shows potential as a methodology to enhance guidelines for urban streams restoration, conservation and management.