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Limit Values (limit + value)
Selected AbstractsUse of various processes for pilot plant treatment of wastewater from a wood-processing factoryJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 3 2001Nikolaos S Athanasopoulos Abstract The wastewater from a wood-processing factory is characterized by a high COD, chlorides and nitrogen content. Various treatment processes were applied to treat this wastewater in pilot-scale units. By applying one-stage denitrification,activated sludge biological treatment it was not possible to remove nitrogen. Nitrification was inhibited by wastewater compounds. By applying a second stage of a nitrification biofilter it was possible to have a high degree of nitrification. The denitrification was complete. With biological methods the reduction of COD, and -N and -N concentrations to acceptable values was not achievable. Physical,Chemical methods as H2O2/UV, electrolysis and ozonation were used as post-treatment of effluents from the biological system. Radical degradation, initiated by the powerful hydroxyl radicals which are generated from H2O2 by UV activation, is used for wastewater post-treatment. The combination of H2O2/UV was not suitable for post-treatment of this wastewater. With electrolysis, -N and COD removal can be complete. The total amount of ammonia and organic nitrogen converted to nitrate nitrogen for current density of 1.15,Adm,2 and energy consumption of 71.6,kWhm,3 was 0.35,gdm,3. Further biological denitrification is required for -N removal to permitted values. Energy consumption for the elimination of 1,kg COD was 40.4,kWh and 35.8,kWh for current densities of 0.7,Adm,2 and 1.15,Adm,2 respectively. The energy required to reach the limit value of COD equal to 150,mgdm,3 for current density of 1.15,Adm,2 was 71.6,kWhm,3. With ozonation, the COD removal can be complete. Further biological nitrification,denitrification is required to remove -N and -N to permitted values. At pH 7.0, in order to reach the limit value of COD equal to 150,mgdm,3, specific ozone dose was 6.0,g per g of COD removed and the total amount of ammonia and organic nitrogen converted to nitrate nitrogen was 0.25,gdm,3. The total equivalent energy required is estimated to be 75.0,kWhm,3. © 2001 Society of Chemical Industry [source] Dipole moments of polyenic oligomeric systems.JOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 9 2005Part II, allenes, molecular organic wire resistivities: polyacetylenes, polyynes Abstract Polyacetylenic, allenic and polyynic molecular wire series, containing electron-donor (D) and electron-acceptor (A) groups as two terminal units of the oligomeric bridge (D,wire,A), can be well described by means of a one-dimensional conduction model, which considers a scattering process of electrons through the charge-transfer conduction bridge. The conduction constants (,i) of the oligomeric structures of the three molecular series under study were determined from the functional dependence between the dipole moment of the oligomers (,n) and the ,-molecular orbital bridge length (L). According to our one-dimensional molecular organic wire model: where ,o is the dipolar moment of the first compound of the oligomeric series without a bridge unit (n,=,0) and ,, is a limit value for L,,,,. By means of the Landauer theoretical expression for the conductance of a metallic one-dimensional conductor and our molecular wire conduction constants (,i), we determined the intrinsic resistivities associated with the molecular resistances of these oligomeric wires. Using this approach we determined, for the first time, the linear and non-linear contributions to the net molecular resistivity. The order of magnitudes of the linear resistivities determined in these oligomeric systems agrees very well with the expected results of experimental measurements for macroscopic wires. Copyright © 2005 John Wiley & Sons, Ltd. [source] Investigation of hard lubricant coatings in space in orbit around the moonLUBRICATION SCIENCE, Issue 4 2002V. M. Yarosh Abstract This paper reports on friction tests of a hard lubricant coating conducted in orbit around the Moon. The measurements included those taken in terrestrial conditions in a vacuum chamber, at the launch site, and in lunar orbit. The paper includes a description of an autonomous friction simulator that was mounted outside the spacecraft. In this device, two types of friction, ,shaft-bush' and ,disc-indenter', have been tested. For the first time, a long experiment exploring the tribological characteristics of an antifriction coating in a real space environment in a lunar satellite orbit has been carried out. Over a fifteen-month period, the friction units were run in the space environment. These tests indicated a tendency for the friction coefficient to reduce to a limit value in such an orbit and environment. [source] Governance challenges and the prevention of industrial environmental accidents: the case of finlandENVIRONMENTAL POLICY AND GOVERNANCE, Issue 6 2008Nina Wessberg Abstract This paper examines the challenges faced in governing accidental industrial emissions. Accidental emissions are unexpected situations where harmful runaway emissions are released into the environment, causing damage to people, ecosystems, human property and company images. We claim that in Finland the practices of environmental authorities do not encourage companies to prevent accidental emissions in the most effective way. According to our study, based on action research and case study augmented with document analysis and interviews, authorities operate under three different kinds of frame: an environmental permit frame, a risk prevention frame and a major accident prevention frame. Accidental industrial emissions are, in our view, best governed under the risk prevention frame, where practices and management systems are addressed covering the entire complex socio-technical nature of an industrial process. However, environmental authorities, in Finland, focus on environmental permit frames, stressing limit values, hence concentrating on managing the industrial process component by component. This approach may be suitable for the governing of continuous emissions, but not that of accidental emissions. Copyright © 2008 John Wiley & Sons, Ltd and ERP Environment. [source] Developing a critical load approach for national risk assessments of atmospheric metal deposition,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 3 2006Jane R. Hall Abstract The critical load approach has been proposed for evaluation of the need to reduce atmospheric emissions of metals that lead to transboundary transport and deposition across Europe. The present study demonstrates and evaluates the application of a critical load approach for national-scale risk assessment of metal deposition in the United Kingdom. Critical load maps, calculated using critical limits based on pH-dependent free metal ion activities, are presented. Current concentrations of lead and cadmium in soils are compared with two sets of critical limit values: First, limits based on the reactive soil concentration, and second, a pH-dependent free ion critical limit function, which takes into account variable soil characteristics across the country. The use of these two models leads to different conclusions about which areas of the United Kingdom are at greatest risk, partly because of differences in the range of values of pH and organic matter in soils used in ecotoxicological experiments and in the national database. Critical loads were calculated based on free ion critical limits; the critical loads were lowest in the south and east of the country and were associated with higher soil pH, lower runoff, and lower soil organic matter. [source] Environmental issues related to end-of-life options of plastics containing brominated flame retardantsFIRE AND MATERIALS, Issue 5 2004Lein Tange Abstract Bromine is used as the building block for some of the most effective flame retarding agents available to the plastics industry today. They are used to protect against the risk of accidental fires in a wide range of Electrical and Electronic Equipment (EEE). Brominated flame retardants (BFRs), as all flame retardants, act to decrease the risk of fire by increasing the fire resistance of the materials in which they are applied. There is a perception that BFRs affect adversely the end-of-life management of plastics through formation of Polybrominated Dibenzo Dioxins and Dibenzo Furans (PBDD/F). In fact, there exists a wide range of data and practical experience demonstrating that the end-of-life management of plastics containing BFRs is fully compliant with legislation setting the strictest limit values for PBDD/F and is fully compatible with an integrated waste management concept. Copyright © 2004 John Wiley & Sons, Ltd. [source] Guideline threshold limit values (TLVs) for discomfort in repetitive assembly workHUMAN FACTORS AND ERGONOMICS IN MANUFACTURING & SERVICE INDUSTRIES, Issue 5 2007L. O'Sullivan This study focused on two of the main occupational risk factors associated with work-related musculoskeletal disorders in light repetitive electronic assembly work, namely repetition and force. Present-day evaluation techniques are primarily posture based and show low sensitivity with regard to rating repetition and force. A simulated assembly task was conducted to investigate the interactions of risk factors and the suitability of hand activity level (HAL) and TLV values for electronics assembly work. Subjects completed the assembly task for three levels of repetition and force. For each treatment a subjective rating of discomfort was recorded. Repeated measures ANOVA identified repetition and force as highly significant factors in light electronic assembly work ( p < .001, p < .05, respectively). The task was also rated using HAL and normalized peak forces (NPF). This study questioned the ability of TLVs in rating discomfort and amendments to the TLVs are suggested. © 2007 Wiley Periodicals, Inc. Hum Factors Man 17: 423,434, 2007. [source] Water quality and hydrogeochemical characteristics of the River Buyukmelen, Duzce, TurkeyHYDROLOGICAL PROCESSES, Issue 20 2005Rustem Pehlivan Abstract The River Buyukmelen is located in the province of Duzce in northwest Turkey and its water basin is approximately 470 km2. The Aksu, Kucukmelen and Ugursuyu streams flow into the River Buyukmelen. It flows into the Black Sea with an output of 44 m3 s,1. The geological succession in the basin comprises limestone and dolomitic limestone of the Y,lanl, formation, sandstone, clayey limestone and marls of the Akveren formation, clastics and volcano-clastics of the Caycuma formation, and cover units comprised of river alluvium, lacutrine sediments and beach sands. The River Buyukmelen is expected to be a water source that can supply the drinking water needs of Istanbul until 2040; therefore, it is imperative that its water quality be preserved. The samples of rock, soil, stream water, suspended, bed and stream sediments and beach sand were collected from the Buyukmelen river basin. They were examined using mineralogical and geochemical methods. The chemical constituents most commonly found in the stream waters are Na+, Mg2+, SO2,4, Cl, and HCO3, in the Guz stream water, Ca2+ in the Abaza stream water, and K+ in the Kuplu stream water. The concentrations of Na+, K+, Ca2+, Mg2+, SO2,4, HCO,3, Cl,, As, Pb, Ni, Mn, Cr, Zn, Fe and U in the Kuplu and Guz stream waters were much higher than the world average values. The Dilaver, Gubi, Tepekoy, Maden, Celik and Abaza streams interact with sedimentary rocks, and the Kuplu and Guz streams interact with volcanic rocks. The amount of suspended sediment in the River Buyukmelen in December 2002 was 120 mg l,1. The suspended and bed sediments in the muddy stream waters are formed of quartz, calcite, plagioclase, clay (kaolinite, illite and smectite), muscovite and amphibole minerals. As, Co, Cd, Cr, Pb, Ni, Zn and U have all accumulated in the Buyukmelen river-bed sediments. The muddy feature of the waters is related to the petrographic features of the rocks in the basin and their mineralogical compositions, as most of the sandstones and volcanic rocks (basalt, tuffite and agglomerate) are decomposed to a clay-rich composition at the surface. Thus, the suspended sediment in stream waters increases by physical weathering of the rocks and water,rock interaction. Owing to the growing population and industrialization, water demand is increasing. The plan is to bring water from the River Buyukmelen to Istanbul's drinking-water reservoirs. According to the Water Pollution Regulations, the River Buyukmelen belongs to quality class 1 based on Hg, Cd, Pb, As, Cu, Cr, Zn, Mn, Se, Ba, Na+, Cl,, and SO2,4; and to quality class 3 based on Fe concentration. The concentration of Fe in the River Buyukmelen exceeds the limit values permitted by the World Health Organization and the Turkish Standard. Because water from the River Buyukmelen will be used as drinking water, it will have an adverse effect on water quality and humans if not treated in advance. In addition, the inclusion of Mn and Zn in the Elmali drinking-water reservoir of Istanbul and Fe in the River Buyukmelen water indicates natural inorganic contamination. Mn, Zn and Fe contents in the waters are related to geological origin. Moreover, the River Buyukmelen flow is very muddy in the rainy seasons and it is inevitable that this will pose problems during the purification process. Copyright © 2005 John Wiley & Sons, Ltd. [source] Theoretical investigation of the cavity expansion problem based on a hypoplasticity modelINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 5 2001V. A. Osinov Abstract The problem of the symmetric quasi-static large-strain expansion of a cavity in an infinite granular body is studied. The body is assumed to be dry or fully drained so that the presence of the pore water can be disregarded. Both spherical and cylindrical cavities are considered. Numerical solutions to the boundary value problem are obtained with the use of the hypoplastic constitutive relation calibrated for a series of granular soils. As the radius of the cavity increases, the stresses and the density on the cavity surface asymptotically approach limit values corresponding to a so-called critical state. For a given soil, the limit values depend on the initial stresses and the initial density. A comparison is made between the solutions for different initial states and different soils. Applications to geotechnical problems such as cone penetration test and pressuremeter test are discussed. Copyright © 2001 John Wiley & Sons, Ltd. [source] Use of copper(II)/ethylene diamine-cotton complex for the adsorption of residual dyesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2007Mohamed Hassen V. Baouab Abstract The chemical modification of cotton is performed by successive reactions with thionyl chloride followed by ethylene diamine (ED) to prepare aminoalkyl amino cotton namely ED-cotton. Evidence of attaching ethylene diamine groups onto cotton is provided by nitrogen determination and thermogravimetry analysis. Because of complexation, the ethylene diamine-grafted groups immobilizes Cu(II) ions from buffered solution at pH 6. The formation of a 1/1 complex is assessed by the adsorption limit values. The binary system [Cu(II)/ED-cotton] is then tested for the adsorption of two acid dyes (Acid Blue 25 and Calmagite) as ligands in the metal-coordinating process. The adsorption of Cu(II) onto ED-cotton and of the dyes onto Cu(II)/ED-cotton is followed spectrometrically. The observed stoichiometries of the ternary-formed complex [Dye/Cu(II)/ED-cotton] are 1/1/1 with Acid Blue 25 and 0.75/1/1 with Calmagite at 20°C. The Langmuir and Freundlich isotherms constants for the adsorption of the tested dyes onto Cu(II)/ED-cotton are evaluated from the experimental data, but better agreement is obtained by using the composite isotherm of Jossens. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1389,1396, 2007 [source] Quantification of the water/lipid affinity of melatonin and a pinoline derivative in lipid modelsJOURNAL OF PINEAL RESEARCH, Issue 4 2007Jamila Mekhloufi Abstract:, This study assessed the location of melatonin (N-acetyl-5-methoxytryptamine) and of a pinoline derivative (GWC22) [6-ethyl-1-(3-methoxyphenyl)-2-propyl-1,2,3,4-tetrahydro-beta-carboline], when present in lipid assemblies such as linoleate micelles, phosphatidylcholine liposomes or low density lipoproteins (LDL). The efficiency of radical scavenging by these compounds is highly dependent on their partitioning between the lipidic and aqueous phases. We determined the proportion of melatonin or GWC22 in the aqueous and lipid phases of each system (concentrations of the antioxidants ranging between 3 × 10,5 and 10,4 m) by assaying melatonin or GWC22 by HPLC/UV detection, or by fluorescence for melatonin in micelles. Our results show that melatonin and GWC22 were preferentially located in the aqueous phase of micelles (68.4% and 59.0%, respectively), whereas only 30.5% of melatonin and 39.0% of GWC22 were found in the lipid phase. By contrast, in phosphatidylcholine liposomes, both compounds were essentially present in the lipid phase (73.5% for melatonin and 79.1% for GWC22, versus 25.9% and 19.5% in the aqueous phase, respectively). In the case of LDL, 99.9% of the melatonin added was found in the methanol/water extracting phase containing phospholipids, unesterified cholesterol and apolipoprotein B100. The partitioning of melatonin and GWC22 in linoleate micelles gave new insights on the marked protective effect of GWC22 towards radiation-induced lipid peroxidation and allowed us to determine more accurately the lower limit values of the reaction rate constants of the two molecules studied with lipid peroxyl radicals, i.e. k(LOO,+melatonin) , 9.0 × 104m,1s,1 and k(LOO,+GWC22) , 3.5 × 105m,1s,1. [source] Integrable operators and canonical differential systemsMATHEMATISCHE NACHRICHTEN, Issue 1-2 2007Lev Sakhnovich Abstract In this article we consider a class of integrable operators and investigate its connections with the following theories: the spectral theory of the non-self-adjoint operators, the Riemann-Hilbert problem, the canonical differential systems, the random matrices theory and the limit values of the multiplicative integral. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Use of structural alerts to develop rules for identifying chemical substances with skin irritation or skin corrosion potentialMOLECULAR INFORMATICS, Issue 3 2005Etje Hulzebos Abstract In this paper structural alerts for acute skin lesions were categorized as irritation or corrosion or a combination of corrosion/irritation alerts. Categorizing the alerts according to their mechanisms of skin irritation and corrosion and connecting them with physicochemical property limits characterizing their domain of applicability provides strategies to save test animals and costs. These alerts can be used for positive classification of chemicals causing skin irritation or skin corrosion according to EU and OECD guidelines. This paper is the third in the series of four papers describing practical, user-friendly and mechanism-based approaches for predicting when chemicals are likely to irritate or corrode the skin. In the first paper the mechanisms of skin irritation and corrosion were described. In the second paper the physicochemical property limit values for chemicals not causing skin irritation and corrosion were given. In the third paper, described here, structural alerts associated with chemicals causing skin irritation and corrosion were identified and characterized. In the fourth paper, the Skin Irritation Corrosion Rules Estimation Tool (SICRET) was described that allows users to classify chemicals as either not causing skin irritation and corrosion based on physicochemical property limit values or irritating or corrosive to the skin based on structural alerts. [source] Use of Physicochemical Property Limits to Develop Rules for Identifying Chemical Substances with no Skin Irritation or Corrosion PotentialMOLECULAR INFORMATICS, Issue 9 2004Ingrid Gerner Abstract This is believed to be the first paper to promote the use of rules based on (quantitative) structure-activity relationship [(Q)SAR] models for identifying chemicals that are not likely to cause a specific adverse health effect, viz., skin irritation or corrosion. The purpose of this paper is to describe limit values for specific physicochemical properties that are appropriate for identifying chemical substances that have no skin irritation or corrosion potential. These physicochemical properties include melting point, molecular weight, octanol-water partition coefficient, surface tension, vapour pressure, aqueous solubility and lipid solubility. Based on analyses of 1833 chemicals, physicochemical properties for limits were defined to determine that when a chemical's physicochemical properties were either greater or less than these limits that these chemicals would have no skin irritation or corrosion potential. To facilitate classification and labeling, the application domains of these limits were constructed to correspond with the European Union's risk phrases for chemicals classified for skin irritation/corrosion, viz., R 34, R35 or R38. This is the second paper of four companion papers. The first paper discussed mechanisms that can lead to significant skin irritation or corrosion after acute exposures to chemicals. The third paper described the application of structural alerts to identify chemical substances with skin irritation or corrosion potential. The fourth paper described the Skin Irritation Corrosion Rules Estimation Tool (SICRET), a user-friendly tool that allows non-(Q)SAR experts to identify chemical substances with skin irritation or corrosion potential based on physicochemical property limits and structural alerts. [source] Collagen dynamics in articular cartilage under osmotic pressureNMR IN BIOMEDICINE, Issue 8 2006Göran Zernia Abstract Cartilage is a complex biological tissue consisting of collagen, proteoglycans and water. The structure and molecular mobility of the collagen component of cartilage were studied by 13C solid-state NMR spectroscopy as a function of hydration. The hydration level of cartilage was adjusted between fully hydrated (,80 wt% H2O) and highly dehydrated (,30 wt% H2O) using the osmotic stress technique. Thus, the conditions of mechanical load could be simulated and the response of the tissue macromolecules to mechanical stress is reported. From the NMR measurements, the following results were obtained. (i) Measurements of motionally averaged dipolar 1H,13C couplings were carried out to study the segmental mobility in cartilage collagen at full hydration. Backbone segments undergo fast motions with amplitudes of ,35° whereas the collagen side-chains are somewhat more mobile with amplitudes between 40 and 50°. In spite of the high water content of cartilage, collagen remains essentially rigid. (ii) No chemical shift changes were observed in 13C cross-polarization magic angle spinning spectra of cartilage tissue at varying hydration indicating that the collagen structure was not altered by application of high osmotic stress. (iii) The 1H,13C dipolar coupling values detected for collagen signals respond to dehydration. The dipolar coupling values gradually increase upon cartilage dehydration, reaching rigid limit values at ,30 wt% H2O. This indicates that collagen is essentially dehydrated in cartilage tissue under very high mechanical load, which provides insights into the elastic properties of cartilage collagen, although the mechanical pressures applied here exceed the physiological limit. Copyright © 2006 John Wiley & Sons, Ltd. [source] Packaging materials for fermented milk: effects of material crystallinity and polarity on food qualityPACKAGING TECHNOLOGY AND SCIENCE, Issue 3 2001S. E. A. Jansson Abstract The ability of a packaging material to protect the food product and extend its shelf-life depends on several material properties. In this work the effects of material crystallinity and polarity on the quality of fermented milk were studied. The fermented milk is a high-quality Swedish product, similar to yoghurt. The quality of the food product was determined as a function of storage time by containing the liquid in pouches of different materials. The material crystallinity was varied by using very low-density polyethylene, high-density polyethylene and aluminium laminate as packaging materials. Aluminium was used on account of its ,100%' gas-tightness. The polarity was varied by comparing an aliphatic polyketone with polyethylene of similar crystallinity. The carbon dioxide (CO2) and oxygen (O2) contents in the headspace of the pouches were determined. The food quality was determined by measuring whey syneresis, viscosity and the content of desired Bifidobacteria, as well as of undesired yeast and mould. A trained taste panel determined the degree of acidity and of the sparkling taste. It was found that the content of CO2 increased and that of O2 decreased in the pouches with increasing degree of crystallinity and increasing polarity. The sparkling taste of fermented milk was a clear function of the headspace CO2 content. The data presented here could thus be used to ,design' a package for a desired sparkling taste of the fermented milk by selecting a certain material crystallinity. Whey syneresis, viscosity and content of Bifidobacteria were found to be independent of pouch material. While the degree of whey syneresis and the viscosity increased with increasing storage time, the content of Bifidobacteria slowly decreased. The content of yeast and mould in the liquid was below the existing limit values for foodstuffs. The degrees of acidity and sparkling taste were highest for the liquids contained in aluminium and polyketone pouches, although the differences in acidulous taste between the various pouch materials were small. Copyright © 2001 John Wiley & Sons, Ltd. [source] Unusual High Exposure to Ultraviolet-C RadiationPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 4 2006Andrea Trevisan ABSTRACT ?1 UV radiation is known to cause acute and chronic eye and skin damage. The present case report describes a 90 min accidental exposure to UV-C radiation of 26 medical school students. Germicidal lamps were lit due to a malfunctioning of the timer system. Several hours after irradiation exposure, all subjects reported the onset of ocular symptoms, subsequently diagnosed as photokeratitis, and skin damage to the face, scalp and neck. While the ocular symptoms lasted 2,4 days, the sunburn-like condition produced significant erythema followed by deep skin exfoliation. The irradiation was calculated to be approximately 700 mJ cm,2 absorbed energy, whereas the actual radiation emitted by the lamps was 0.14 mW cm,2 (the radiometric measurements confirmed these calculi, because the effective irradiance measured from the height of the autopsy table to about 1 m under the UV-C lamp varied from 0.05 to 0.25 mW cm,2) but, more likely, the effective irradiance, according to skin phototype and symptoms, was between 50 and 100 mJ cm,2. The ocular and skin effects produced by such a high irradiation (largely higher than that accepted by the American Conference of Governmental Industrial Hygienists [ACGIH] threshold limit values [TLVs]) appeared reversible in a relatively short time. [source] Neurotoxic effect of occupational exposure to mixed organic solvents in Korea: Posturographic studyAMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 5 2009Jae-Beom Park MD Abstract Background This study used static posturography to investigate the neurotoxic effects on workers exposed to mixed organic solvents at low concentrations under the levels of the threshold limit values (TLV). Methods Forty-one workers from four plants exposed to mixed solvents and 90 non-exposed referents were examined. The lifetime cumulative biological exposure (CE) was estimated according to subject's occupational history and biological monitoring results. Static posturography and questionnaire were the basis of data collection. Results The mean exposure index of mixed organic solvents of four plants was 0.47 (SD: 0.33, range: 0.08,1.39). The exposed group showed a larger sway area and length under the eye open condition than did the non-exposed group. In a multiple linear regression, a significant positive association was demonstrated between postural sway area and CE. Conclusions This study results suggest that the exposure to organic solvents under TLV levels may cause disturbance in postural stability. Am. J. Ind. Med. 52:429,437, 2009. © 2009 Wiley-Liss, Inc. [source] Reassessment of occupational exposure limitsAMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 6 2008Hans Stouten MSc Abstract Background Although the Netherlands currently has its own procedure for evaluating chemical compounds and setting occupational exposure limits (OELs), most of these limits were originally adopted in the 1970s from threshold limit values (TLVs) set by the American Conference of Governmental Industrial Hygienists (ACGIH). However, beginning in the late 1980s, criticism about non-scientific considerations being used to set TLV's suggested that TLVs might not offer sufficient health protection to workers. This situation prompted the Dutch Ministry of Social Affairs and Employment to request that the Health Council of the Netherlands reassess the health protection of MAC values that were contained in the 1994 Dutch MAC list. Methods Criteria documents were prepared for 161 compounds. They were evaluated by a committee of the Health Council of the Netherlands consisting of international experts who reassessed the toxicological hazards of these substances and recommended, whenever possible, health-based OELs. The results of the reassessment by the Health Council were compared with the MAC values of the 1994 Dutch MAC list, ACGIH TLVs, and existing German OELs. Results The toxicological database met the committee's criteria for a health-based OEL for only about 40% of the compounds. Conclusions Many older MAC values were either too high or not scientifically supported and therefore not health-based. Am. J. Ind. Med. 51:407,418, 2008. © 2008 Wiley-Liss, Inc. [source] Respiratory diseases caused by occupational exposure to 1,5-naphthalene-diisocyanate (NDI): Results of workplace-related challenge tests and antibody analysesAMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 4 2001X. Baur Abstract Background 1,5-naphthalene-diisocyanate (NDI) is an aromatic diisocyanate with a very low vapor pressure which is mainly used in the automotive industry. Methods In the present study we described five cases with workplace-related asthma and one case with extrinsic allergic alveolitis associated with pulmonary hemorrhage after NDI exposure. Results Corresponding to case histories, extrinsic alveolitis on asthmatic reactions in three subjects and a rhinitis reaction in one patient could be reproduced by inhalative challenge tests to NDI at a concentration of 10 ppb. Preliminary IgE and IgG antibody analyses in patients' sera did not produce significantly positive results. Conclusions According to the outcome of our tests and in comparison with several other studies, we conclude that NDI should be classified as potent airway-sensitizing substance. Improved workplace conditions and decrease in threshold limit values should therefore be recommended. Am. J. Ind. Med. 39:369,372, 2001. © 2001 Wiley-Liss, Inc. [source] | ||||||||||||||||||||||