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Flank face chamfers are an effective way to suppress vibrations and increase the productivity of milling processes. The underlying process damping mechanism is the so-called indentation effect. The effect describes the process damping as a result of an additional force due to the indentation of workpiece material under the flank face. In literature, this force is commonly modeled by the volume indented under the flank face and a process damping coefficient. To determine the process damping coefficient, various approaches with partly contradictory results exist. In this paper, a novel method to calculate the process damping coefficient based on process forces measurements in orthogonal cutting is applied for steel machining. The method considers ploughing effects of flank face chamfer and cutting edge rounding as well as plastic deformation effects. In the current investigation, the approach is applied to different cooling strategies, chamfer widths, and cutting speeds. The results show that the cutting speed has the most significant influence on the process damping coefficient. With increasing cutting speed, the process damping coefficient increases, which can be attributed to strain rate hardening effects. [ABSTRACT FROM AUTHOR]

Metalworking fluids (MWF) are mainly emulsions of oil in water containing additives such as corrosion inhibitors, emulsifiers, defoamers, and biocides. Microbial contamination of MWF is almost systematic, and some of their constituents serve as nutrients for contaminating microorganisms. Biocides for MWF are protection products used to counter microbial contaminations and growth. Ideally, a biocide for MWF should have the following non-exhaustive criteria: have a broad-spectrum activity, be usable at low concentrations, be compatible with the formulation and the physical-chemical properties of MWF, be stable over time, retain its effectiveness in the presence of soiling, have no corrosive action on metals, present no danger to humans and the environment, be inexpensive. The future lies in the development of new molecules with biocidal activity corresponding to these ideal specifications, but in the meantime, it is possible to improve the performance of existing molecules currently on the market. Different strategies for potentiation of the activity of existing biocides are possible. The compatibility of the potentiation strategies with their use in metal working fluids is discussed.

Metal working fluids are used in machining processes of many hard-to-cut materials to increase tool life and productivity. Thereby, the metal working fluids act on the thermal and on the mechanical loads of the tool. The changing mechanical loads can mostly be attributed to the changing friction between rake face and chip and changes in the chip formation, e.g., the contact length between rake face and chip. However, analyzing those effects is challenging, since a detailed look at the chip formation process is prevented by the metal working fluid. In this paper, a novel planing test rig is presented, which enables high-speed recordings of the machining process and process force measurements while using metal working fluids. Experiments reveal that process forces are reduced with increasing pressure of the metal working fluid. However, the average friction coefficient only changes slightly, which indicates that the reduced process forces are mainly the result of reduced contact lengths between rake face and chip. [ABSTRACT FROM AUTHOR]

Background: Extensive use of metal working fluids degrades their chemical composition. They should be treated using a safe method. Chemical coagulation-flocculation process is one the treatment methods. Objective: The aim of this study was to optimize the coagulation-flocculation process using calcium chloride in metal working fluids treatment. Methods: This laboratory based study was performed in School of Health affiliated to Qazvin University of Medical Sciences in 2014. Using calcium chloride and a six-compartment jar, the efficiency of coagulation-flocculation process was assessed for removal of chemical oxygen demand (COD) and turbidity and amount of released oil. Central composite design (CCD) and response surface methodology (RSM) were applied to optimize the treatment operation parameters (pH and dosage of coagulant). Quadratic models were developed for calculation of the three responses (COD, turbidity, and released oil). Findings: The optimum condition for coagulation-flocculation process was seen after treatment with 4.2 g/L calcium chloride at pH 3.71 in which COD and turbidity removal efficiency were 93% and 96.9%, respectively and the amount of released oil was 31.8 ml. The level of desirability was 91.2%. The values of laboratory study were in good agreement with the values predicted by the model. Conclusion: Metal working fluids treatment with calcium chloride was efficient in the removal of pollution parameters. Dosage of calcium chloride was similar to the conventional coagulants such as Alum, but its efficiency was higher.

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Abstract: Three biodegradable/ecofriendly polyalkylene glycol esters 1,4-PTHC3, 1,4-PTHC6 and 1,4-PTHC8 [polyglycol containing 1:4 mol fraction of propylene oxide (PO) and tetrahydrofuran (THF)] esterified with propionic acid (C3 fatty acid), hexanoic acid (C6 fatty acid) and octanoic acid (C8 fatty acid) were synthesized via two-step reaction mechanism. Initially, propylene oxide and tetrahydrofuran were polymerized in 1,2 dichloroethane to obtain a polymer 1,4-PTH (polyglycol containing 1:4 mol fraction of PO and THF) with molecular weight (Mn¯) 1070.7. Finally, esterification of 1,4-PTH was done with varied fatty acids, i.e., C3, C6 and C8 fatty acid catalyzed by p-toluenesulfonic acid and toluene as solvent to obtain final products 1,4-PTHC3, 1,4-PTHC6 and 1,4-PTHC8 having the molecular weights (Mn¯) 1154.78, (Mn¯) 1192.86 and (Mn¯) 1220.91, respectively. The molecular structure and crystallinity of the synthesized poly(propyleneoxide-co-tetrahydrofuran) ester was studied by FT-IR, X-ray diffraction and DSC. The physicochemical properties like; pour point (ASTM 97), kinematic viscosity (ASTM 445), viscosity index (ASTM 2270), refractive index, density, thermal stability, autoignition temperature (IS 7895), corrosion stability and oxidation stability (IP 48) were determined. The extreme pressure (IP 239) and antiwear properties (ASTM D 4172) were also evaluated in terms of weld load and average wear scar diameter, respectively. Hence all the properties so determined were compared with the specifications of lube oils and it was revealed that these poly(propyleneoxide-co-tetrahydrofuran) esters, i.e., 1,4-PTHC3, 1,4-PTHC6 and 1,4-PTHC8 had suitable physical and tribological properties to be used as base stock for compressor lubricant, metal working fluid and fire-resistant hydraulic fluid.Graphical Abstract: [ABSTRACT FROM AUTHOR]

Occupational exposure to microbially contaminated metal working fluids (MWF) can cause hypersensitivity pneumonitis (HP). An important step in the diagnosis of HP is to identify the triggering antigen by detection of corresponding specific IgG antibodies (sIgG). As commercial sIgG tests are currently not available, protein antigens were prepared from MWF-workplace samples and from MWF-typical bacterial isolates. In 57 % of suspected HP-cases (n = 30) elevated sIgG concentrations were measured to at least one MWF-relevant antigen, of which Mycobacterium immunogenum was most prominent (88 %), followed by Pseudomonas oleovorans and Pseudomonas spec (82 % each), MWF-antigen mix and Pseudomonas alcaliphila (65 % each). Elevated sIgG concentrations to other microorganisms were measured to Micropolyspora faeni (82 %) and Aureobasidium pullulans (77 %). Correlation of sIgG values of all tested microbial antigens showed a significant relationship of MWF-antigen mixture to Pseudomonas antigens, but a low correlation to moulds. These newly prepared MWF-antigens are useful tools for the diagnosis of patients with suspected MWF-HP and are available for further investigations. • Linking microbial exposure in the workplace and occupational HP is an important aspect of the diagnostic workflow. • The newly established and validated serological sIgG test tools described here contribute to this process. • The most prominent MWF-antigens among serologically positive serum samples were M. immunogenum and Pseudomonas. • Most IgG reactive mould and actinomyces antigens were A. pullulans and M. faeni. • Significant correlations occurred among sIgG to pseudomonas species or to mould species, but not between bacteria and mould. [ABSTRACT FROM AUTHOR]

Metal working fluidis widely used as coolant, lubricant and rust remover in mechanical processing. Oil mist will be formed in the process of metal working fluid. The composition of oil mist is complex, which can produce many adverse effects on the environment and operators. This paper reviews the health hazards of metal working fluid oil mist on human skin, respiratory system, teratogenic and carcinogenic aspects, and discusses the establishment of occupational exposure limits in workplaces of oil mist in foreign countries, in order to provide reference for the prevention and control of occupational health risks of metal working fluid oil mist and the establishment of occupational exposure limits of oil mist in workplaces in China.

Patients with airway symptoms working in metal working industries are increasing, despite efforts to improve the environmental air surrounding the machines. Our aim was to analyse the amount of endotoxin in size-separated airborne particles of metal working fluid (MWF) aerosol, by using the personal sampler Sioutas cascade impactor, to compare filter types, and to compare the concentration of airborne endotoxin to that of the corresponding MWFs. In a pilot field study, aerosols were collected in two separate machine halls on totally 10 occasions, using glass fibre and polytetrafluoroethylene (PTFE) filters in parallel at each station. Airborne endotoxin was distributed over all size fractions. While a major part was found in the largest size fraction (72%, 2.5-10 µm), up to 8% of the airborne endotoxin was detected in the smallest size fraction (<0.25 µm). Comparing the efficiency of the filter types, a significantly higher median endotoxin level was found with glass fibres filters collecting the largest particle-size fraction ( 1.2-fold) and with PTFE filters collecting the smallest ones (5-fold). The levels of endotoxin in the size-separated airborne particle fractions correlated to those of the MWFs supporting the aerosol-generating machines. Our study indicates that a significant part of inhalable aerosols of MWFs consists of endotoxin-containing particles below the size of intact bacteria, and thus small enough to readily reach the deepest part of the lung. Combined with other chemical irritants of the MWF, exposure to MWF aerosols containing endotoxin pose a risk to respiratory health problems. [ABSTRACT FROM AUTHOR]

An extensive microbiological study has been carried out in a membrane bioreactor fed with activated sludge and metal-working fluids. Functional diversity and dynamics of bacterial communities were studied with different approaches. Functional diversity of culturable bacterial communities was studied with different Biolog™ plates. Structure and dynamics of bacterial communities were studied in culturable and in non-culturable fractions using a 16S rRNA analysis. Among the culturable bacteria, Alphaproteobacteria and Gammaproteobacteria were the predominant classes. However, changes in microbial community structure were detected over time. Culture-independent analysis showed that Betaproteobacteria was the most frequently detected class in the membrane bioreactor (MBR) community with Zoogloea and Acidovorax as dominant genera. Also, among non-culturable bacteria, a process of succession was observed. Longitudinal structural shifts observed were more marked for non-culturable than for culturable bacteria, pointing towards an important role in the MBR performance. Microbial community metabolic abilities assessed with Biolog™ Gram negative, Gram positive and anaerobic plates also showed differences over time for Shannon's diversity index, kinetics of average well colour development, and the intensely used substrates by bacterial community in each plate. [ABSTRACT FROM AUTHOR]

Cryogenic machining opens up new industrial perspectives in difficult-to-cut materials like nickel-based alloys. In particular, drilling is an operation that generates high thermal and mechanical loading to the drill. Therefore, tool performance, hole geometry and surface integrity can be highly affected. The objective of this study is to analyse tool performance during drilling of IN718 using conventional metal working fluids (MWF) and cryogenic cooling conditions, and correlate it with the thermo-mechanical phenomena. This study is conducted with standard coated cemented carbide twist drills, designed to work with MWF. The results show that drill performance under cryogenic cooling is strongly affected by its geometry. The axial force, drilling torque and tool wear/failure are higher under cryogenic cooling when compared to conventional MWF. Therefore, in order to take advantage of the cryogenic machining, new drill design is required, which currently is not available on the market. [ABSTRACT FROM AUTHOR]

Nanofluid, fluid suspensions of nanometer sized particles are revolutionizing the field of heat transfer area. Addition of nano-particles to the base fluid also alters the lubricating properties by reducing the friction. In grinding process, friction between the abrasive grains and the workpiece is a key issue governing the main grinding output. It has a direct influence on grinding force, power, specific energy and wheel wear. Moreover, high friction force increases the heat generation and lead to thermal damage in the surface layer of the ground work. Hence, any effort towards the friction control will enhance the component quality significantly. In this study, nanofluid as metal working fluid (MWF) is made by adding 0.05, 0.1, 0.5 and 1% volume concentration of Al 2 O 3 and CuO nano-particles to the water during the surface grinding of Ti–6Al–4V in minimum quantity lubrication (MQL) mode. Surface integrity of ground surface, morphology of the wheel, and chip formation characteristics are studied using surface profilometer, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and stereo zoom microscopy (SZM). Coefficient of friction was estimated On-Machine using the measured forces. The results showed that the type of nanoparticle and its concentration in base fluid and the MQL flow rate play a significant role in reducing friction. Application of nanofluid leads to the reduction of tangential forces and grinding zone temperature. The cooling effect is also evident from the short C-type chip formation. MQL application with Al 2 O 3 nanofluid helps in effective flushing of chip material from the grinding zone, thereby solving the main problem during the grinding of Ti–6Al–4V. [ABSTRACT FROM AUTHOR]

Almost all machining industries in Sri Lanka use mineral oil–based and synthetic oils as metal working fluids during machining. But their usage has potential for long-term environmental pollution and threat to workers’ health. Therefore, much effort has been focused on research and development of eco-friendly and hazard-free alternatives to mineral oil–based metal working fluids, and the use of vegetable oils is one such alternative. This study was focused on investigating the easy access of vegetable oils in Sri Lanka and most commonly machined metals in the local industry, so that the outcome would be much more beneficial to the local industries. After several tests with 10 candidate vegetable oils, white coconut oil is selected as base oil and the results of a successful questionnaire survey directed to select mild steel and AISI 304 steel as the machining metals. Machining experiments were planned using Taguchi methods, and the variation of the surface roughness was tracked with respect to four variable parameters depth of cut, feed rate, spindle speed and metal working fluid. Two mathematical models were developed to predict the surface roughness and optimize the parameters. Further experiments were conducted to investigate the effects of metal working fluid for smooth- and rough-cut conditions. These experiments revealed that white coconut oil is a better metal working fluid for mild steel, while soluble oil favors AISI 304 steel. Different thermal conductivities of metals cause the coconut oil to act differently while machining two metal types. [ABSTRACT FROM PUBLISHER]

Emulsified fluids are used in many industrial and consumer areas, for instance as products in the food or health industry as well as technical fluids in the machining industry. Metalworking fluids (MWF) are used as coolants and lubricants in metalworking processes. During their usage MWF emulsions may change their physical and chemical properties, which influences their performance and decrease the physical stability and therefore their lifetime. This article discusses results of turbidimetric spectra measurement of MWF emulsions to be used for process control, MWF quality monitoring and formulation purposes. Therefore, laboratory experiments have been carried out investigating the physical stability. Metal working emulsions have been treated and destabilised by different concentrations of salts. The destabilisation process was monitored by undiluted turbidity measurements and evaluated by the temporal change of the wavelength exponent. Thus, it was possible to determine specific conditions, for example a specific critical salt concentration for maintaining, stability of the MWF formulations. [ABSTRACT FROM AUTHOR]

Monitoring of emulsion properties is important in many applications, like in foods and pharmaceutical products, or in emulsion polymerisation processes, since aged and 'broken' emulsions perform worse and may affect product quality. This study reports the use of an 'in-line' turbidity sensor coupled with a neural network model to monitor droplet size distributions of metal working fluid emulsions (MWF), a case where emulsion aging affects product quality. The data from the sensor were used to fit the model for droplet size distribution estimation. The technique was applied to monitor the destabilisation of commercially available MWF with good accuracy. [ABSTRACT FROM AUTHOR]

Abstract: Water miscible metal working fluids (MWF) are prone to contamination by bacteria and fungi. In the present work it was investigated which components of a model MWF emulsion were most readily degraded by microorganisms and which are relatively resistant to biodegradation. The microbial community colonising an MWF emulsion, during its lifetime under in-use conditions was analysed up to species level. Shifts in the composition of microbial community were related to chemical changes in the MWF emulsion over time. [Copyright &y& Elsevier]

Microalgae recently emerged as an alternative resource to terrestrial plant-based biomass for the bio-economy, limiting the competition with food production. Whereas its main field of application is into biofuels and bioenergy products, recent developments have shown the potential of microalgae biomass for product manufacturing, including Metal Working Fluids (MWF). The environmental impact of such products, as compared to fossil-based alternatives, remains however questionable as there is a knowledge gap in published literature on the topic. This paper presents a comprehensive Life Cycle Assessment (LCA) of microalgae-based MWF, the first of its kind to our best knowledge. Primary life cycle inventories data were collected related to the production of microalgae oil from two distinct algae species, Nannochloropsis gaditana and Acutodesmus obliquus. The inventory considered the cultivation over four seasons into open raceway photobioreactor and into close vertical photobioreactor. The LCA results were then compared with the LCA of rapeseed oil-based MWF and conventional mineral oil-based MWF, to identify optimization levers. The study demonstrates that major improvements are needed to make the microalgae-based MWF process better from an environmental standpoint than its vegetable and mineral alternatives. Depending on algae species impacts from vegetable and mineral alternatives are 55–95% lower on Climate Change, 20–95% lower on Water use, and 85–95% lower on Fossil resource use. Electricity consumption during the cultivation and harvest stages, fertiliser and nutrient consumptions are the most significant contributors to environmental impacts. LCA results were found to be highly sensitive to the scenarios assessed, the background electricity mix and the allocation choices on co-products from the production of microalgae oil. • Comprehensive Life Cycle Assessment of microalgae-based Metal Working Fluid (MWF). • Primary life cycle inventories for microalgae production at semi-industrial scale. • Major improvements required so the microalgae-based MWF becomes environmentally competitive with conventional alternatives. • LCA results are sensitive to algae cultivation technical and seasonal variability. • Allocation of co-products from algae oil production significantly affects LCA results. [ABSTRACT FROM AUTHOR]

Abstract: In this study the effects of operating parameters on the ultrafiltration of metal working fluids were considered and the optimum conditions for filtration were estimated. In order to reduce the number of experiments an experimental design method (Taguchi) was applied. Seven parameters including pH, oil concentration, temperature, salt (NaCl, CaCl2), feed velocity, and pressure were studied at three levels (low, medium, and high). The oil was water soluble cutting oil and the membrane was an ultrafiltration membrane (C100F) which was supplied by the NADIR Company. The filtration was done at total recycle conditions. During the experiment samples from feed and permeate were collected in order to measure the retention of oil, the zeta potential, and the oil drop size. The obtained results showed a flux increase with increasing pH. The highest flux was achieved at alkaline conditions but the highest retention was observed when the pH was acidic (lower limit in experiment). It was also observed that the zeta potential was mostly affected by pH and CaCl2. The biggest zeta potential resulted in the lowest permeate flux. The drop size measurement showed that a bigger drop size usually gave a higher flux. The effect (increase in flux) of salt addition implied that at acidic conditions the effect was smaller than at alkaline conditions. As a conclusion, an alkaline pH, a high pressure, a high temperature and a low amount of CaCl2 gave the optimum conditions. [Copyright &y& Elsevier]

Abstract: The effect of calcium on the stability of a commercial MWF is characterized through the experimental determination of the stability ratio, W. Three experimental methods of stability ratio evaluation are investigated. (1) The initial slope of the absorbance versus time curve is used to estimate the rate of coagulation. (2) Absorbance measurements are used to estimate with time. The stability ratio is determined from the slope of versus time. (3) Photon correlation spectroscopy (PCS) measurements of the volume distribution with time are used to estimate with time. Electrophoretic mobility was also measured and used to determine the fast coagulation concentration of the MWF. The accuracy of the experimentally determined stability ratios is evaluated using a population balance coagulation model. The model predicts the population distribution of a coagulating dispersion with time based on an initial particle size distribution and stability ratio. The model results were compared with the PCS-measured distributions to determine which stability ratio evaluation method best describes the stability of the MWF emulsion studied. Using the initial slope of the absorbance versus time curve to determine the fast coagulation concentration correlates well with electrophoretic mobility measurements. However, using absorbance measurements to determine the rate of coagulation underestimates the stability ratio of the MWF studied by orders of magnitude. values calculated from absorbance measurements provide a reasonable estimate of the stability ratio but inconsistencies in the method decrease its reliability. The stability ratio derived from PCS measurements appears to provide the most accurate, reliable description of MWF stability. [Copyright &y& Elsevier]

In Japan, the lubricating oil used for the internal combustion engine of passenger cars is usually exchanged for fresh oil after running a distance in the range from 3,000 to 10,000 km. Refining of the used engine oil is very costly because friction-reducing additives containing sulfur, phosphorus, etc., are included in the oil. Therefore, wasted engine oil (used engine oil) is burned in many cases. This investigation was conducted to effectively reuse wasted engine oil without chemical refining. Performance of used engine oil as a gear-cutting oil was examined by conducting five kinds of experiments: (a) chemical analyses of the oils, (b) measurements of friction coefficients on the four-ball tester, (c) tool wear tests using a lathe, (d) tool life tests using a gear-cutting machine, and (e) accuracy and surface finish of the cut gears. In contrast to general expectations, longer tool lives were obtained when the used engine oils were used instead of a high-grade gear-cutting oil. The reason for this was discussed and it was concluded that used engine oil may be used as a high-performance gear-cutting oil if health risks for workers are removed. [ABSTRACT FROM AUTHOR]

Metal working fluids (MWFs) have been widely known to cause asthma and neoplasia of the larynx, pancreas, rectum, skin and urinary bladder (Textbook of Clinical Occupational and Environmental Medicine (1994) 814; Am. J. Ind. Med. 32 (1997) 240; Am. J. Ind. Med. 33 (1997) 282; Am. J. Ind. Med. 22 (1994) 185). Other non-neoplastic respiratory effects in industrial workers attributed to MWFs include increased rates of cough, phlegm production, wheeze, chronic bronchitis and chest tightness (Eur. J. Resir. Dis. 63(118) (1982), 79; J. Occup. Med. 24 (1982) 473; Am. J. Ind. Med. 32 (1997) 450). The epidemic and endemic nature of immune mediated lung morbidity commonly known as hypersensitivity pneumonitis in workers from several different industries using MWFs has been well documented (J. Allergy clin. Immunol. 91 (1993) 311; Chest 108 (1995) 636; MMWR45 (1996) 606; Am. J. Ind. Med. 32 (1997) 423). We studied morphological/functional and antioxidant outcomes in lungs after inhalation exposure of vitamin E deficient mice to MWF (27 mg m−3 17 weeks, 5 days a week, 6 h a day). Mice were given vitamin E deficient (<10 IU kg−1 vitamin E) or basal diets (50 IU kg−1 vitamin E) for 35 weeks. Inhalation exposure to MWF started after 18 weeks on diet. Microscopic observation of lungs from mice given vitamin E deficient or sufficient diets revealed no inflammation or morphological alteration after exposure to MWF. Mice given vitamin E deficient diet exhibited a significant decrease (P<0.05) in breathing rate, peak inspiratory/expiratory flow, minute ventilation, and tidal volume compared with sufficient controls. However, no differences were found after exposure to MWF in pulmonary function, with the exception of tidal volume which also significantly decreased (P<0.05). Exposure to MWF reduced vitamin E, protein thiol and ascorbate level in lungs. Exposure to MWF in combination with a vitamin E deficient diet resulted in significantly enhanced accumulation of peroxidative products compared with vitamin E deficient controls. This is the first report that describes the increase of oxidative stress in the lungs after MWF exposure. [Copyright &y& Elsevier]

The coolant system for metal working is a typical example of a tribomechanical system, where several wear mechanisms are present simultaneously. The metal particles in the coolant system have the appearance of tiny chips, grains, coils of fine wire and so on. Particulate composition varies significantly depending on the cutting process and operating conditions, as well as coolant characteristics and coolant systems. During the cutting process, the metal working fluid is also exposed to changes due to: chemical reactions between its substances; tool surfaces and workpieces; the presence of particles and high temperatures on contact surfaces.The aim of the present work is to study the tribological processes, wear and failures on tribomechanical system elements of machine tools by exposing them to fluid for metal working with particles. The experimental investigations of effect of metal working fluids on tribological processes of tribomechanical system elements have been carried out at a metal working factory. The investigations were carried out on 30 lathes in four periods of time. The obtained results have proved that water based metal working fluids have quite a great influence on tribological processes, wear and failures of tribomechanical system elements of machine tools. [Copyright &y& Elsevier]

Metal working fluids (MWFs) are widely used in industry for metal cutting, drilling, shaping, lubricating, and milling. Potential for dermal exposure to MWFs exists for a large number of men and women via aerosols and splashing during the machining operations. It has been reported earlier that occupational exposure to MWFs causes allergic and irritant contact dermatitis. Previously, we showed that dermal exposure of female and male B6C3F1 mice to 5% MWFs for 3 months resulted in accumulation of mast cells and elevation of histamine in the skin. Topical exposure to MWF also resulted in elevated oxidative stress in the liver of both sexes and the testes in males. The goal of this study was to evaluate the interaction between oxidative stress in the skin and topical application of MWF. Oxidative stress in skin of B6C3F1 mice of both sexes was generated by intradermal injection of the hydrogen peroxide (H[sub 2]O[sub 2])-producing enzyme, glucose oxidase with polyethylene glycol (GOD+PEG). In mice given GOD+PEG, topical treatment with MWF (200 μl, 30%, for 1, 3, or 7 days) resulted in a mixed inflammatory cell response, accumulation of peroxidative products, and reduction of GSH content in the skin. Such changes were not observed with MWF treatment alone. These data indicate that oxidative stress can enhance dermal inflammation caused by occupational exposure to MWF. Toxicology and Industrial Health (2000) 16, 267–276. [ABSTRACT FROM AUTHOR]

Over 10 million workers in the United States are exposed to metal working fluids (MWFs) through dermal contact and/or inhalation of aerosolized fluids. The objective of this study was to elucidate the response of skin to dermal exposure to MWFs. Four- to six-week-old B6C3F1 mice of both sexes were divided into eight groups (n=5/group) and exposed to 200 μl of 0%, 5% (pH 7 and 9.7) and 100% (pH 10.4), unused MWFs/H[sub 2]O by topical application to the unshaven back (cervical to sacral region), twice a week for 6 weeks. Skin-mast cell number in females of most treated groups and of two male groups (100% and 5%, pH 7) were significantly higher than the control groups. Eventhough both males and females (treated with 100% MWF/H[sub 2]O) showed an increase in the skin-histamine levels (38% and 41%, respectively), this increase was significant in females only (ANOVA, P≤0.05). Dermal exposure to 100% MWFs increased liver weight significantly in both sexes. Ulcers and associated inflammation were seen in the skin of mice treated with 100% unused MWFs and sacrificed at 6 weeks, but not in the recovery groups. Hypertrophy of the sebaceous gland epithelium is present in all mice treated for 6 weeks and sacrificed immediately. However, only the mice treated with 100% MWF retained the hypertrophy of this epithelium after a 6-week recovery period. In conclusion, dermal exposure to unused semi-synthetic MWF penetrates the normal skin, induces mast cell accumulation in the skin, produces hypertrophy of the sebaceous glands, and may affect females more than males. [ABSTRACT FROM AUTHOR]