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PubMed1989

Mutagenicity of airborne particulates in the rubber industry.

The aim of this work was to evaluate the mutagenic activity of airborne particulate matter in the rubber industry. Air was sucked through Whatman glass-fibre filters with Staplex pumps and adsorbed substances and fume particles were extracted with acetone or toluene for 2 h in a ultrasonic cleaner. After separation of the insoluble solid phase by filtration, solvent was evaporated at a temperature of 70 degrees C in an argon atmosphere. The residue was stored at -20 degrees C. Mutagenicity was determined by the Salmonella plate incorporation assay with the tester strain TA98 and activity is related either to the weight of aerosol (rev mg-1) or to the volume of atmospheric sample (rev m-3). The fumes emitted from the tyre tread line, calender feeding, and tyre vulcanizing processes, showed the highest mutagenic activity (55-211 rev mg-1, + S9). At these and at other workplaces (extruder mill, carbon black station, mixer loading), mutagenic activity related to the volume of air was in the range of 22-158 rev m-3, + S9. The results indicate the need to reduce and monitor mutagenic contamination in order to increase the safety of work in the rubber industry.

Air Pollutants, Occupational↗
PubMed2000

Feasible boundaries of aqueous two-phase systems with NH(3) and CO(2) as recyclable volatile salts.

Aqueous two-phase systems (ATPSs) have great potential for use in the downstream processing of fermentation products. A major drawback of these systems, limiting application in industrial practice up till now, is the consumption of large amounts of auxiliary materials such as polymers and salts. Making use of alternative auxiliaries can diminish this relatively large discharge. A possible approach is to make use of volatile salts induced by combinations of ammonia and carbon dioxide that can be recycled to the extraction system. As part of an ongoing research effort on ATPSs with volatile salts, this work aims at getting more information on the system boundaries or operating conditions of these systems in terms of phase behavior. The results show that the NH(3)/CO(2) ratio is an important parameter that has a large influence on the system boundaries. Both for systems with PEG 2000 and PEG 4000, this ratio has to be larger than about 1.75 to make a liquid-liquid phase separation possible. The most optimal ratio seems to be 2.0 for reasons of solution composition and absence of solid salt.

Ammonia↗
PubMed1984

Chemical and toxicological aspects of coal liquefaction and other complex mixtures.

Chemists, biologists, and ecologists at Battelle's Pacific Northwest Laboratories are developing a data base to aid engineers in the safe design of coal liquefaction process options. Objectives of this effort have been to identify and evaluate long-term health and environmental issues, evaluate options to permit environmentally acceptable design, and assess risk to man and the environment from deployment of a large-scale coal liquefaction industry. Chemically complex materials produced by various coal liquefaction processes, and under various stages of process design and operating conditions, have been screened for potential health and environmental effects. Biologically active materials have been fractionated and rescreened. Chemical constituents of biologically active fractions have been identified, and the environmental fate of problematic agents is currently being determined. This approach, linking engineering and life sciences research, is also relevant to the development of other energy technologies and industries that produce chemically complex materials. Results indicate that full-boiling-range coal-derived liquids are generally more active than shale oil and petroleum crudes in biological and ecological test systems. Several biologically active agents have been identified, including primary aromatic amines (PAA), polynuclear aromatic hydrocarbons (PAH), and phenols. Some components of coal-derived materials are taken up by biota and metabolized. Hydrotreating, a refining or upgrading process, reduces PAA, PAH, and phenol content, as well as mutagenicity, carcinogenicity, and toxicity of coal liquids. Selective distillation restricts PAA and PAH content, as well as mutagenicity and carcinogenicity to high-boiling-range coal liquids. Other process conditions (i.e., extraction severity, catalyst age, etc.) and environmental factors influence chemical characteristics and biological activity of coal-derived materials. Eliminating toxic input of coal liquids to ecological test systems results in partial system recovery. Recent findings indicate that biological responses to a particular chemical agent vary, depending on whether that material is presented to the organism or environment as a pure compound or in a complex mixture. Thus, results of studies with pure compounds cannot be used alone to predict effects of complex mixtures. The research approach described here provides guidance to solve environmental problems before regulatory agencies require limitations or facility construction is completed, and costs of process changes are higher.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed2006

Shear bond strength of new and recycled brackets to enamel.

The purpose of this study was to evaluate in vitro the shear bond strength of recycled orthodontic brackets. S2C-03Z brackets (Dental Morelli, Brazil) were bonded to the buccal surfaces of 50 extracted human premolars using Concise Orthodontic chemically cured composite resin (3M, USA). The teeth were randomly assigned to 5 groups (n=10), as follows. In group I (control), the bonded brackets remained attached until shear testing (i.e., no debonding/rebonding). In groups II, III and IV, the bonded brackets were detached and rebonded after recycling by 90-microm particle aluminum oxide blasting, silicon carbide stone grinding or an industrial process at a specialized contractor company (Abzil-Lancer, Brazil), respectively. In group V, the bonded brackets were removed and new brackets were bonded to the enamel surface. Shear bond strength was tested in an Instron machine at a crosshead speed of 0.5 mm/min. Data were analyzed statistically by ANOVA and Tukey's test at 5% significance level. There was no statistically significant difference (p>0.05) between the control brackets (0.52 kgf/mm2), brackets recycled by aluminum oxide blasting (0.34 kgf/mm2) and new brackets attached to previously bonded teeth (0.43 kgf/mm2). Brackets recycled by the specialized company (0.28 kgf/mm2) and those recycled by silicon carbide stone grinding (0.14 kgf/mm2) showed the lowest shear strength means and differed statistically from control brackets (0.52 kgf/mm2) (p<0.05). In conclusion, the outcomes of this study showed that bracket recycling using 90-microm aluminum oxide particle air-abrasion was efficient and technically simple, and might provide cost reduction for orthodontists and patients alike.

Analysis of Variance↗
PubMed2002

Solidification/stabilisation of arsenic bearing fly ash from the metallurgical industry. Immobilisation mechanism of arsenic.

When a fly ash waste material from a copper refining process containing large amounts of As2O3 is solidified using cement and lime, the arsenic concentration in the leachate can be lowered to ca. 5 mg/l in a saturated solution of Ca(OH)2. It is shown that the decrease of the concentration in the leachate, mainly of As(III), is due to the formation of insoluble CaHAsO3 in the leachate in the presence of Ca(OH)2. This method is compared with a method whereby use is made of oxidation of the waste before solidification to oxidise As(III) to As(V) using H2O2. The arsenic concentration in the leachate of the extraction test of an oxidised S/S sample was lowered to ca. 0.5 mg/l, a factor of 10 below the one for a non-oxidised sample. It is shown that the decrease of the concentration in the leachate mainly of As(V) is due to the formation of insoluble Ca3(AsO4)2 in the presence of Ca(OH)2. Extensive use was made of the speciation program MINTEQA2, to clarify the immobilisation of arsenic.

Arsenic↗
PubMed2004

Liquid chromatography of active principles in Sophora flavescens root.

Herbal medicines were one of the major resources for healthcare in earlier stages, and some traditional herbal medicines have been in use for more than 2000 years. Currently, they are attracting more and more attention of the modern pharmaceutical industry, as scientists has become aware that herbs have almost infinite resources for medicine development. This review provides an overview of the analytical approaches applied in the researches concentrated on various aspects of the matrine-type alkaloids in Sophora flavescens root. Emphasis will be laid on the analytical processes of high-performance liquid chromatography (HPLC), capillary electrophoresis (CE), as well as gas chromatography (GC) methods. The sample extraction, separation and detection have been summarized. In addition, the applications of chromatographic determinations are introduced for the main matrine-type alkaloids in S. flavescens root, such as matrine, sophoridine, sophocarpine, lehmannine, sophoramine, oxymartine, oxysophocarpine, cytosine and aloperine. The advantages and limitations of HPLC, CE and GC methods in the analytical applications of the alkaloids are also discussed.

Chromatography, Gas↗
PubMed2004

Evaluation and optimization of chromium removal from tannery effluent by microemulsion in the Morris extractor.

In this research a surfactant derived from a vegetable oil (coconut oil) was used to remove chromium from a tannery effluent. In the extraction process, a Morris extractor was used. Important variables used in assessing the optimization of the process included agitation speed, solvent rate and total flow rate. The experiments were conducted using a 2(3) factorial design. According to the response from the experimental design, the effects of each variable were calculated and the interactions between them determined. Response surface methodology was employed to study the effects of the studied variables. The optimum operational conditions were: agitation speed, 428 rpm; solvent rate, 0.37; total flow rate, 2.0 l h(-1). After extraction process, a re-extraction study was accomplished and the obtained results showed that chromium could be removed from the microemulsion phase by hydrochloric and sulphuric acidic solutions, what allows its reuse in the leather manufacturing process.

Algorithms↗
PubMed1999

The degradation of sodium O,O-diethyl dithiophosphate by bacteria from metalworking fluids.

The breakdown of sodium O,O-diethyl dithiophosphate (O,O-diethyl phosphorodithioate) by four bacterial strains (tentatively identified as strains of Aeromonas, Pseudomonas, Flavobacterium and Bacillus) isolated from contaminated metalworking fluids was shown to involve the successive formation of ethanol, aldehyde and orthophosphate. An acid phosphodiesterase was identified in cell-free extracts that was five- to sevenfold enhanced in specific activity in bacteria grown on O,O-diethyl dithiophosphate as sole phosphorus source, compared with bacteria grown on orthophosphate. This is thought to initiate the breakdown process.

Bacillus↗
PubMed2002

Heavy metals extraction from anaerobically digested sludge.

This paper reports on the chemical extraction efficiency in the removal of heavy metals from sludge from an activated-sludge system, which receives as influent both industrial and municipal wastewater. Utilizing a series of chemical extractants in a sequential order comprised the first phase of the research, called sequential chemical extraction (SCE). The work started with the well-known Tessier method followed by Veeken and by Sims and Kline SCE schemes. Afterwards, modified versions of Tessier and Veeken schemes were applied. The second phase, named chemical extraction using pH progressive changes, concerns an alternative to the extraction process. Four acids were tested: nitric, hydrochloric, oxalic and citric and the pH values as well as the time were varied. Some conclusions reveal that although modifying Tessier and Veeken schemes provides more consistent results, SCE is still an imperfect method regarding specificity and selectivity. Besides, it is not advisable to apply one SCE scheme developed for one specific situation to another one, once the accurateness of the method depends on several factors such as sort of material and chemicals, contact time, temperature, etc. The extraction efficiency increases using nitric or hydrochloric acids at low pH values, promoting high extraction efficiency level.

Bacteria, Anaerobic↗
PubMed2005

Physicochemical characterization and mercury speciation of particle-size soil fractions from an abandoned mining area in Mieres, Asturias (Spain).

Soils from old cinnabar mining areas usually exhibit high Hg contents, whose mobility depends on soil parameters and environmental conditions. This paper presents the study of the Hg speciation in soil samples from an abandoned Hg mine and metallurgical plant in Mieres (Asturias, Spain), in relation to their mineralogical and chemical composition and their particle-size distribution. A characterization of samples was made by X-Ray Diffraction Spectrometry, Scanning Electron Microscopy and Atomic Absorption and Emission Spectroscopy analyses. A sequential extraction method was applied to establish Hg mobility in the samples and their grain-size subsamples. The highest Hg mobility was found in well-developed soils, as a consequence of the adsorption processes by iron and manganese oxides, whereas in those more contaminated soils, a higher proportion of Hg was leached in the non-mobile fraction. A higher Hg mobility was found in the finest grain-size subsamples, probably due to the accumulation of clay minerals and oxides in these ranges.

Adsorption↗
PubMed2004

Dutch analysis for P-recovery from municipal wastewater.

There is a considerable practical interest in phosphorus recovery from water authorities, elementary P-industry, fertilizer industry and regulators in a number of countries. Due to a handful of full-scale plants worldwide, P-recovery can be seen as technically feasible. However, the economic feasibility of P-recovery from sewage can still be judged as dubious. The most important reason for this is that the prices of the techniques (in euro/tonne P) are much higher compared to the prices of phosphate rock. In this paper an analysis is given to recover phosphate from municipal wastewater for the elementary P-industry Thermphos International B.V. and the fertiliser industry Amsterdam Fertilizers B.V. in The Netherlands. Several scenarios are evaluated and the end products of these scenarios are compared to the quality required by both industries. From a Dutch study it became clear that all end products from the final sludge treatment do not provide a good source of secondary phosphate. As a consequence of this, the most preferred possibility for P-recovery is to extract phosphate before sludge goes to the final sludge treatment. Different scenarios can be selected based on the position of P-recovery in the WWTP configuration, the type of P-recovery product, and the precipitation technique. Local conditions will determine which scenario is the most expedient. Because it is more realistic to judge a practical situation instead of theoretical estimations based on literature, some local situations have to be assessed in sufficient detail to gain more feeling for the expenses and possible savings of P-recovery. One important actor that should be involved in the process management around P-recovery, is the national government. Especially, the Government have the responsibility for sustainable development and should have attention for some stimulation of P-recovery in The Netherlands. Water authorities and the P- and fertilizer industry made already some good steps.

Agriculture↗
PubMed2001

Production of the biocontrol agent Pantoea agglomerans strain CPA-2 using commercial products and by-products.

The aim of this paper was to find the nitrogen and carbon sources that provide maximum biomass production of strain CPA-2 of the biocontrol agent Pantoea agglomerans and minimum cost of media, whilst maintaining biocontrol efficacy. To reduce the cost of media, commercial products and by-products were tested. P. agglomerans can be produced using a combination of nitrogen sources such as yeast extract (5 g l(-1)) and dry beer yeast (10 g l(-1)) with inexpensive carbohydrates such as sucrose (10 g l(-1)) and molasses (20 g l(-1)), respectively, maintaining the efficacy of the biocontrol agent against Penicillium digitatum and P. italicum on oranges. The results obtained in this study could be used to provide a reliable basis for a scale-up of this fermentation process to an industrial level.

Biomass↗
PubMed2005

Solid olive residues: insight into their phenolic composition.

Solid olive residues (SOR) are byproducts of the olive-milling process, but they have an increasing importance in the pharmaceutical industry due to their rich content of biophenols. Such compounds are studied widely for their antioxidant and antimicrobial activities, but there is a lack of information about their quantitative recovery. This research highlighted the key role played both by the selection of the cultivar and by the degree of olive fruit ripening on the phenolic content on the SOR. The extraction methods were selected to reach the best quantitative results mainly using a safe food solvent. In light of the results the Soxhlet extraction with ethanol could be proposed as preferential for a higher recovery of verbascoside and its analogues.

Chromatography, High Pressure Liquid↗
PubMed2006

Evaluation of Escherichia coli O157:H7 growth media for use in test-and-hold procedures for ground beef processing.

Since the mid-1990s, the beef industry has used a process called test and hold, wherein beef trim and ground beef are tested to keep products contaminated with Escherichia coli O157:H7 out of commerce. Current O157:H7 detection methods rely on a threshold level of bacterial growth for detection, which is dependent on the growth medium used. Twelve media were examined for growth and doubling time: buffered peptone water (BPW), SOC (which contains tryptone, yeast extract, KCl, MgCl2, and glucose), buffered peptone water plus SOC (BPW-SOC), Bacto-NZYM, RapidChek E. coli O157:H7 medium, BioControl EHEC8 culture medium, Neogen Reveal for E. coli O157:H7--Eight Hour medium (Neogen Reveal 8), BAX System medium for E. coli O157:H7 (BAX) BAX System medium for E. coli O157:H7 MP (BAX-MP), modified E. coli broth, nutrient medium, and tryptic soy broth (TSB). All media were tested at 37 or 42 degrees C under static or shaking conditions. The eight media with the highest total CFU per milliliter and most rapid doubling times were BPW-SOC, NZYM, RapidChek, EHEC8, Neogen Reveal 8, BAX, BAX-MP, and TSB. The ability of these eight media to enrich E. coli O157:H7 in ground beef was further evaluated through time-course experiments using immunomagnetic separation. Of these media, TSB was the easiest to prepare, had a wide application base, and was the least expensive. In the test-and-hold process, the normal ratio of medium to product is 1:10. In this study, a 1:3 ratio worked as well as a 1:10 ratio. Processors using test-and-hold procedures could use 1 liter of TSB to enrich for E. coli O157:H7 in a 375-g sample instead of the usual 3.375 liters, thus saving reagents, time, and labor while maintaining accuracy.

Animals↗
PubMed2004

Changes in toxicity and genotoxicity of industrial sewage sludge samples containing nitro- and amino-aromatic compounds following treatment in bioreactors with different oxygen regimes.

GOALS, SCOPE AND BACKGROUND: From 2005, deposition of organic waste will be banned in Sweden. Likewise, in Germany and Austria, similar bans are being planned, and further countries will probably follow. Thus, there is a need to develop new methods and to refine established techniques for sludge management in the whole of the European Union. For this end, there is also an urgent need for appropriate ecotoxicological approaches to elucidate and assess the hazard potential of sewage sludge. Therefore, the present study was designed to assess the capacity of various established sludge treatment methods using different oxygen regimes to degrade recalcitrant nitro-substituted organic compounds and reduce their toxicity. Sewage sludge samples from a wastewater treatment plant in Sweden (Cambrex Karlskoga AB, industrial area Björkborn) receiving wastewater from industries manufacturing pharmaceutical substances, chemical intermediates and explosives were processed with different sludge treatment methods. Among other treatment methods, bioreactors (for anaerobic and aerobic sludge treatment) were used. In the present investigation, a battery of in vitro bioassays was employed to compare the cytotoxic and genotoxic potentials of different fractions of sludge samples in order to elucidate whether the treatments were suitable to reduce the toxicity of the sludge. METHODS: In order to investigate the cytotoxicity of the extracts of treated and untreated sludge samples, the acute cytotoxicity test with the permanent cell line RTL-W1 was used. Genotoxicity was tested by means of the comet assay (single cell gel electrophoresis) with RTL-W1 cells, and mutagenicity was assessed with the Ames test using the Salmonella typhimurium strains TA98, TA98NR and TA100. Sludge toxicity was tested in different fractions of organic extracts produced by acetone and hexane extractions. The subsequent clean-up procedure (silica gel chromatography and elution with hexane and dichloromethane) resulted in two fractions, a lipophilic hexane-fraction and a semi-lipophilic dichloromethane-fraction. For the genotoxicity and mutagenicity tests, these fractions were reunited at equal ratios. RESULTS AND DISCUSSION: The acute cytotoxicity test with RTL-W1 cells revealed a high cytotoxic potential for the semi-lipophilic DM-fractions of all sludge samples with NR50 values (= effective concentration for 50% cell death in the neutral red test) from 8.9 up to 20 mg sludge d.w./ml medium. A low cytotoxic potential for the hexane fractions of the untreated sludge samples (NR50 400 to > 400 mg sludge d.w./ml medium) was observed, whereas the hexane fractions of the treated sludge samples showed elevated cytotoxicity increasing further with treatment in the bioreactors. The comet assay indicated that three out of eight of the reunited fractions had a significant genotoxic potential. Whereas the genotoxic potential of one sample treated anaerobically was very high with an induction factor of 11.6, a similar sample (taken from the same anaerobic reactor four months later) and one untreated sample showed lower potentials. The samples treated in another anaerobic bioreactor as well as the samples treated aerobically showed no genotoxic potential. Results indicate that aerobic treatment was basically adequate for reducing the genotoxicity of the sludge, whereas anaerobic treatment was only partly useful for reduction of genotoxicity. The Ames test revealed a very high mutagenic potential for the reunited fractions of the untreated sludge samples with strain TA98 (maximum induction factors (IFmax) up to 45) and a relatively high potential for one of the samples treated aerobically (S2, IFmax = 18 (TA98, S9-)), thus documenting the suitability of both anaerobic and aerobic treatments to reduce the mutagenicity of the samples, however, with the aerobic treatment being less effective. CONCLUSIONS: Overall, none of the microbiological treatments for wastewater sludge in bioreactors was found to be ideal for general toxicity reduction of the sludge samples. Whereas cytotoxicity of the sludge increased or levelled off in most cases following either treatment, genotoxicity both increased or decreased after anaerobic treatment, depending on the specific sample. However, mutagenicity could generally be reduced by anaerobic treatment and, to a lesser degree, by aerobic treatment. RECOMMENDATIONS AND PERSPECTIVES: The complex modification of the diverse damage potentials of sludge sample extracts by use of an in vitro biotest battery following treatment for toxicity reduction in bioreactors showed that considerations of different toxicological endpoints is essential for an adequate hazard assessment. Whereas in the case of cytotoxicity reduction, the reactors proved ineffective, mutagenicity could be reduced significantly at least in some cases in this case study.

Biological Assay↗
PubMedDate not supplied

Preparation of unaltered hemoglobin from human placentas for possible use in blood substitutes.

Hemoglobin extracted from human placentas could be used as the basis of blood substitutes provided it could be prepared on a large scale with appropriate oxygen-binding properties. Unfortunately, the industrial conditions under which it is extracted, produce hemoglobin with high oxygen affinity and which is no longer influenced by the classical effectors. These characteristics were shown to be caused by a degradation of the alpha-chain brought about by an arginine carboxypeptidase present in the placental tissues and leading to the disappearance of the C-terminal arginine residue. This carboxypeptidase which is released from the tissues during the process of crushing the frozen placentas, degrades the protein during the chromatographic purification procedure. The addition of an inhibitor of this carboxypeptidase (for example, arginine) as soon as the placentas are thawed and during the chromatographic process, makes it possible to obtain placental hemoglobin with oxygen-binding properties quite similar to those of HbA prepared from peripheral venous blood.

Adult↗
PubMed2006

Spatial variability of arsenic and chromium in the soil water at a former wood preserving site.

Contamination of industrial sites by wood preservatives such as chromated copper arsenate (CCA) may pose a serious threat to groundwater quality. The objective of this study was to characterise the spatial variability of As and Cr concentrations in the solid phase and in the soil water at a former wood impregnation plant and to reveal the fundamental transport processes. The soil was sampled down to a depth of 2m. The soil water was extracted in situ from the vadose zone over a period of 10 months at depths of 1 and 1.5m, using large horizontally installed suction tubes. Groundwater was sampled from a depth of 4.5m. Results showed that arsenic and chromium had accumulated in the upper region of the profile and exhibited a high spatial variability (As: 21-621 mg kg(-1); Cr: 74-2872 mg kg(-1)). Concentrations in the soil water were high (mean As 167 microg L(-1); Cr: 62 microg L(-1)) and also showed a distinct spatial variability, covering concentration ranges up to three orders of magnitude. The variability was caused by the severe water-repellency of the surface soil, induced by the concurrent application of creosote wood preservatives, which leads to strong preferential flow as evident from a dye experiment. In contrast to soil water concentrations, only low As concentrations (<12 microg L(-1)) were detected in the groundwater. High Cr concentrations in the groundwater (approx. 300 microg L(-1)), however, illustrated the pronounced mobility of chromium. Our study shows that at sites with a heterogeneous flow system in the vadose zone a disparity between flux-averaged and volume-averaged concentrations may occur, and sampling of soil water might not be adequate for assessing groundwater concentrations. In these cases long-term monitoring of the groundwater appears to be the best strategy for a groundwater risk assessment.

Arsenates↗
PubMed2005

An improved purification procedure for cyclosporin synthetase.

We have developed expedient and reliable methods to isolate cyclosporin synthetase for in vitro biosynthesis of cyclosporins. We have examined enzyme purification strategies suited to large-scale processing and present a chromatographic sequence that serves as a pilot model for industrial scale preparation of cyclosporin synthetase from cyclosporin producing fungi. A chromatographic sequence consisting of ammonium sulfate precipitation-->gel filtration-->hydrophobic interaction chromatography-->anion exchange chromatography, yielded an electrophoretically homogeneous cyclosporin synthetase preparation (Coomassie G-250 brilliant blue staining). Furthermore, a native polyacrylamide gel electrophoresis system was developed for the isolation of active cyclosporin synthetase enzyme from crude extracts of cyclosporin producing fungi. The environmental factors affecting enzyme stability and the continuity of the in vitro cyclosporin biosynthetic reaction-temperature, pH, and substrate depletion were assessed and manageable conditions have been defined for sustainable cyclosporin biosynthesis with enzyme isolates. Cyclosporin synthetase exhibited an optimal temperature range of 24-29 degrees C and a pH optimum of 7.6. The native enzyme displayed a pI of 5.7, as determined by isoelectric focusing. The industrial implementation of an in vitro biosynthetic approach could potentially prove useful for the production of important therapeutic cyclosporins which occur as only minor fermentation by-products.

Chromatography↗