Induction of chromosome aberrations in the Allium cepa test system caused by the exposure of seeds to industrial effluents contaminated with azo dyes

Numerous potentially mutagenic chemicals have been studied mainly because they can cause damaging and inheritable changes in the genetic material. Several tests are commonly used for biomonitoring pollution levels and to evaluate the effects of toxic and mutagenic agents present in the natural environment. This study aimed at assessing the potential of a textile effluent contaminated with azo dyes to induce chromosomal and nuclear aberrations in Allium cepa test systems. A continuous exposure of seeds in samples of the textile effluent in different concentrations was carried out (0.3%, 3%, 10%, and 100%). Cells in interphase and undergoing division were examined to assess the presence of chromosome aberrations, nuclear changes, and micronuclei. Our results revealed a mutagenic effect of the effluent at concentrations of 10% and 100%. At lower concentrations, the effluent (3% and 0.3%) did not induce mutagenic alterations in the test organism A. cepa. These findings are of concern, since cell damage may be transmitted to subsequent generations, possibly affecting the organism as a whole, as well as the local biota exposed to the effluent discharge. If the damage results in cell death, the development of the organism may be affected, which could also lead to its death. © 2008 Elsevier Ltd. All rights reserved.

Germinação de sementes de pinho-cuiabano sob deficiência hídrica com diferentes agentes osmóticos

The species Schizolobium amazonicum (Huber ex Ducke) commonly known as pinho-cuiabano or paricá, is one of the trees in Amazonian area used for plantings in degraded areas, reforestations and agroforestry systems. The present work evaluated the germinative behaviour of seeds of Schizolobium amazonicum in relation to the hydric stress, defining their levels of tolerance to those limitations in the environment. The seeds were collected from 30 trees in Alta Floresta-MT and submitted the dormancy treatment by submersion into water at 100°C for 1 minute; followed by treatment with fungicide Ridomil and Cercobin 0,25% each, then being left to germinate in a BOD camera at 30°C under a photoperiod of 12 hours. For evaluating the effect of different water potentials in the germinative process, polyethylene glicol (PEG 6000) was used and the salts NaCI and CaCl 2 used to simulate saline stress. The seeds were put to soak in potentials of 0 (control); -0.1 ; -0.2; -0.3; -0.4 and -0.5MPa. For each treatment 5 repetitions of 20 seeds were used in gerbox, placed between filter paper moistened with 20 mL of PEG, NaCI and CaCl 2 solutions. The solutions were changed at intervals of 24 hours for maintenance of the potential. The evaluations of percentages and germination speed were carry out daily for 8 days, being considered germinated the seeds that presented a 2mm root extension or longer. The data were submitted to analysis of variance and averages compared by the Tukey test at 5% probability. It was concluded that osmotic potentials between -0.4 and -0.5MPa inhibited the germination of seeds of Schizolobium amazonicum completely. The osmotic stress caused by CaCl 2, and PEG injured the germination more than did the stress caused by NaCl.

Desempenho de gotejadores com uso de esgoto doméstico tratado

This paper aimed to determine the flow rate of drippers, their flow rate-pressure curve, their equation, their flow rate variation coefficient (VCq), as well as to evaluate the uniformity of water application of the Netafim drip pipe, Tiran 17 model, used for irrigation with domestic wastewater from treated household drain. After 1000 working hours, the blockage of some drippers decreased the uniformity of water application from 98% to lower than 60% and increased the flow variation coefficient to values higher than 0.29.

Diagnóstico da qualidade da água na microbacia do córrego recanto, em americana, no estado de São Paulo

The environmental degradation observed in the Piracicaba, Capivari and Jundiaí watershed has been one of the principal preoccupations of the environmental agencies in the state of São Paulo, Brazil. In this context, there is inserted the Americana county which is cut by streams of unsuitable quality for the human consumption and other uses. The main goal of the present work was evaluated the water quality of the Recanto Creek, affluent of the Quilombo stream, at the Americana county, state of São Paulo, Brazil. The research was developed in the period from March of 2007 to March of 2008, when it was measured the flow and the following physical-chemical water quality parameters: temperature; turbidity; pH; dissolved oxygen (OD); phosphorus (P); ammonia nitrogen (NH 4); nitrate (NO 3); chemical demand of oxygen (DQO), besides total coliforms. The results demonstrated a variation of the flow from 34.3 to 375.2 L s -1, during the evaluated period. The parameters dissolved oxygen, phosphorus, ammonia nitrogen and nitrate presented values out of the limits recommended for rivers of class 3, like the Recanto Creek, suggesting water pollution due to the organic matter disposal.

Caracterização radiométrica de ácidos fosfóricos e seus produtos industriais

The addition of phosphoric acids and their (by)products became a common practice in areas like metal treatment, detergent production, water and effluent treatment, as well by food, beverage and pharmaceutical industries. The phosphoric acids exhibit different radionuclides activity concentration, being important to evaluate the implications for the human and animal health. The 238U concentration in almost all raw acid phosphoric are within the worldwide range and the mean exposure rate for the filtration cake is 10 nGy/h, which is mainly attributed to 40K. The results obtained for total and (bio)available uranium concentration in filtration cake indicate that only 40% is (bio)available for plants. The radionuclides present in phosphoric acid food grade and filtration cake do not raise their concentration in human food chain or soils to harmful levels, consequently, not offering hazard to the ecosystem and animal or human health.

Parâmetros físico-químicos da água e ocorrência de streptococcus spp. em criação intensiva de tilápia no estado do espírito Santo, Brasil

This study evaluated the influence of intensive farming of tilapia on physical and chemical parameters and on the occurrence of Streptococcus spp. in the water of the lake and of cages. Throughout a year, monthly samplings were taken in the rainy and dry seasons for a year, at two sampling sites, lake and net cages. For the determination of water quality, physical and chemical water parameters were evaluated and compared to the standards established by Conama Resolution no. 357/2005. The presence of Streptococcus spp. in the water was determined by plating on blood Agar and biochemical screening. Mean values of water parameters were tested using the Kruskal-Wallis test comparing sampling sites and seasons. Ammoniacal nitrogen (ammoniacal-N), total phosphorus (total-P) levels and occurrence of Streptococcus spp. have increased in the water of the net cages. The mean values of several parameters have decreased during the rainy period, except for pH, temperature and ammoniacal-N. Total-P and dissolved oxygen levels, during dry and rainy periods, respectively, exceeded the standard established for freshwater class 2, recommended for aquaculture, which can be harmful to the fish. Therefore, constant monitoring of the physical,chemical and microbiological water parameters is recommended since the Juara lake is also used for recreational purposes.

2,4-Dichlorophenoxyacetic acid (2,4-D) degradation promoted by nanoparticulate zerovalent iron (nZVI) in aerobic suspensions

Reactive species generated by Fe0 oxidation promoted by O2 (catalyzed or not by ligands) are able to degrade contaminant compounds like the herbicide 2,4-dichlorophenoxyacetic acid. The degradation of 2,4-D was influenced by the concentrations of zero valent iron (ZVI) and different ligands, as well as by pH. In the absence of ligands, the highest 2,4-D degradation rate was obtained at pH 3, while the highest percentage degradation (50%) was achieved at pH 5 after 120 min of reaction. Among the ligands studied (DTPA, EDTA, glycine, oxalate, and citrate), only ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) significantly enhanced oxidation of 2,4-D. This increase in oxidation was observed at all pH values tested (including neutral to alkaline conditions), indicating the feasibility of the technique for treatment of contaminated water. In the presence of EDTA, the oxidation rate was greater at pH 3 than at pH 5 or 7. Increasing the EDTA concentration increased the rate and percentage of 2,4-D degradation, however increasing the Fe0 concentration resulted in the opposite behavior. It was found that degradation of EDTA and 2,4-D occurred simultaneously, and that the new methodology avoided any 2,4-D removal by adsorption/coprecipitation. © 2013 Elsevier Ltd.

Synthesis of PTSH-modified CeO2 nanoparticles: Effect of the modifier on structure, optical properties, and dispersibility

CeO2 nanoparticles were synthesized by the precipitation method and modified with para-toluene sulfonic acid (PTSH), either in situ or post-synthesis. The presence of PTSH in the samples was confirmed by FTIR. PXRD and FTIR analyses showed that the post-synthesis PTSH modification altered the CeO2 structure, whereas the in situ modification maintained intact the crystalline structure and UV-vis absorbance properties. For both in situ and post-synthesis modifications, TEM images revealed the presence of nanoparticles that were 5nm in size. The dispersibility of the in situ PTSH-modified material in a hydrophilic ureasil-poly(ethylene oxide) matrix was investigated using SAXS measurements, which indicated that CeO2 nanoparticles modified with PTSH in situ were less aggregated within the matrix, compared to unmodified CeO2 nanoparticles. © 2013 Elsevier B.V.

Biosorption of cadmium (II) and lead (II) from aqueous solution using exopolysaccharide and biomass produced by Colletotrichum sp.

The biosorption of Cd(II) and Pb(II) ions on biomass and exopolysaccharide (EPS) produced by Colletotrichum sp. fungus has been investigated as a function of contact time, initial pH, initial metal ion concentration, and initial adsorbent concentration in a batch system. Adsorption equilibrium was described by Freundlich and Langmuir isotherms. Adsorption was characterized through granulometry, SEM and EDX analysis. Then, studies were performed to regenerate the adsorbent. Biosorption of metals by biomass and EPS were best described by the Langmuir and Freundlich isotherm, respectively. Results of thermodynamic investigations showed that adsorption reactions were spontaneous (ΔG° < 0), exothermal, and mainly physical. The EPS was able to remove 79 and 98% of cadmium and lead, respectively, and the biomass removed 85 and 84% of cadmium and lead, respectively, in a solution with initial concentration 100 mg L-1, and the four adsorption-desorption cycles of all adsorbents showed up with great regenerative capacity and relative stability after these four cycles, the high potential of these biological materials in sorption has been shown. © 2013 Copyright Balaban Desalination Publications.

The effect of dimethyl sulfoxide (DMSO) on dentin bonding and nanoleakage of etch-and-rinse adhesives

Objective The objective was to examine the effect of a solvent dimethyl sulfoxide (DMSO) on resin-dentin bond durability, as well as potential functional mechanisms behind the effect. Methods Microtensile bond strength (μTBS) was evaluated in extracted human teeth in two separate experiments. Dentin specimens were acid-etched and assigned to pre-treatment with 0.5 mM (0.004%) DMSO as additional primer for 30 s and to controls with water pre-treatment. Two-step etch-and-rinse adhesive (Scotchbond 1XT, 3M ESPE) was applied and resin composite build-ups were created. Specimens were immediately tested for μTBS or stored in artificial saliva for 6 and 12 months prior to testing. Additional immediate and 6-month specimens were examined for interfacial nanoleakage analysis under SEM. Matrix metalloproteinase (MMP) inhibition by DMSO was examined with gelatin zymography. Demineralized dentin disks were incubated in 100% DMSO to observe the optical clearing effect. Results The use of 0.5 mM DMSO had no effect on immediate bond strength or nanoleakage. In controls, μTBS decreased significantly after storage, but increased significantly in DMSO-treated group. The control group had significantly lower μTBS than DMSO-group after 6 and 12 months. DMSO also eliminated the increase in nanoleakage seen in controls. 5% and higher DMSO concentrations significantly inhibited the gelatinases. DMSO induced optical clearing effect demonstrating collagen dissociation. Significance DMSO as a solvent may be useful in improving the preservation of long-term dentin-adhesive bond strength. The effect may relate to dentinal enzyme inhibition or improved wetting of collagen by adhesives. The collagen dissociation required much higher DMSO concentrations than the 0.5 mM DMSO used for bonding. © 2013 Academy of Dental Materials.

Comunidades de peixes e integridade biótica do Córrego da Água Limpa na fase de pré-recuperação de matas ciliares

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Epidemiologia de doenças infecciosas: cólera e doença do caranguejo letárgico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Isolamento e identificação de micobacterias e microrganismos indicadores de contaminação em águas tratadas provenientes do sistema de abstecimento público de Araraquara-SP

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Ensaios de tratamento de efluentes de indústria de chapa dura de fibra de madeira

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Atividade antioxidante, compostos fenólicos totais e cor em abacate ‘hass’ submetido a diferentes tratamentos físicos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)