<b>Bijsluiter</b>. De hyperlink naar het originele document werkt niet meer. Daarom laat Woogle de tekst zien die in dat document stond. Deze tekst kan vreemde foutieve woorden of zinnen bevatten en de opmaak kan verdwenen of veranderd zijn. Dit komt door het zwartlakken van vertrouwelijke informatie of doordat de tekst niet digitaal beschikbaar was en dus ingescand en vervolgens via OCR weer ingelezen is. Voor het originele document, neem contact op met de Woo-contactpersoon van het bestuursorgaan.<br><br>====================================================================== Pagina 1 ======================================================================

<pre>Cyclohexene
(CAS No: 110-83-8)
Health-based Reassessment of Administrative Occupational Exposure Limits
Committee on Updating of Occupational Exposure Limits,
a committee of the Health Council of the Netherlands
No. 2000/15OSH/100 The Hague, March 30, 2004
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<pre>Preferred citation:
Health Council of the Netherlands: Committee on Updating of Occupational
Exposure Limits. Cyclohexene; Health-based Reassessment of Administrative
Occupational Exposure Limits. The Hague: Health Council of the Netherlands,
2004; 2000/15OSH/100.
all rights reserved
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<pre>1     Introduction
      The present document contains the assessment of the health hazard of
      cyclohexene by the Committee on Updating of Occupational Exposure Limits, a
      committee of the Health Council of the Netherlands. The first draft of this
      document was prepared by H Stouten, M.Sc. (TNO Nutrition and Food
      Research, Zeist, The Netherlands).
           The evaluation of the toxicity of cyclohexene has been based on the review
      by the American Conference of Governmental Industrial Hygienists (ACG98).
      Where relevant, the original publications were reviewed and evaluated as will be
      indicated in the text. In addition, in April 1999, literature was searched in the on-
      line databases Medline, Toxline, and Chemical Abstracts, starting from 1966,
      1965, and 1967, respectively, and using the following key words: cyclohexene,
      110-83-8, and 33004-06-7.
           In July 2000, the President of the Health Council released a draft of the
      document for public review. No comments were received.
           An additional search in Toxline and Medline in November 2003 did not
      result in information changing the committee’s conclusions.
2     Identity
      name                    :   cyclohexene
      synonyms                :   cyclohex-1-ene; benzenetetrahydride; tetrahydrobenzene; hexanaphthylene
      molecular formula       :   C6H10
      structural formula      :
      CAS number              :   110-83-8
100-3 Cyclohexene
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<pre>3     Physical and chemical properties
      molecular weight      :    82.1
      boiling point         :    83oC
      melting point         :    -104oC
      flash point           :    -6oC (closed cup)
      vapour pressure       :    at 20oC: 8.9 kPa
      solubility in water   :    insoluble
      log Poctanol/water    :    2.86 (experimental); 2.96 (estimated)
      conversion factors    :    at 20oC, 101,3 kPa: 1 ppm = 3.42 mg/m3
                                                       1 mg/m3 = 0.29 ppm
      Data from ACG98, http://esc.syrres.com.
      Cyclohexene is a highly flammable, colourless liquid, with a sweet odour. An
      odour threshold of 0.18 ppm (0.6 mg/m3) has been reported (Amo83).
4     Uses
      Cyclohexene is used in oil extraction, as a catalytic solvent, and in organic
      synthesis and in the manufacture of adipic acid, maleic acid, and
      tetrahydrobenzoic acid and aldehyde (ACG98, NLM03).
5     Biotransformation and kinetics
      The committee did not find human data on the kinetics of cyclohexene.
           In vitro experiments with microsomal liver preparations showed that
      cyclohexene can be metabolised by cytochrome P450 monooxygenases. Binding
      experiments resulted in difference spectra characteristic of Type I substrates
      (Can74, Jam71). The experiments indicated that under the applied conditions
      cyclohexene is converted into its trans-diol derivative via an epoxide (Lei70,
      Lei71). Formation of 2-cyclohexen-1-ol and 2-cyclohexen-1-one was found as
      well (Lei78). Cyclohexene was not a suicide substrate for cytochrome P450
      (Ort80).
           No cyclohexene oxide could be detected in the blood of rats during a 1-hour
      exposure to 600 ppm (2040 mg/m3) while cyclohexene levels increased to ca.
      2 µg/g blood, in an experiment performed to investigate the phenomenon that
      exposure to alkenes that inactivate cytochrome P450 result in an early peak in
      epoxide blood levels. Cyclohexene did not affect cytochrome P450
100-4 Health-based Reassessment of Administrative Occupational Exposure Limits
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<pre>      concentrations in livers sampled 20 or 360 minutes after starting exposure
      (Map93). Following oral administration of 250 mg/kg bw to rats, a rapid
      decrease in total glutathione content in the liver was measured. When an oral
      dose of 165 mg/kg bw was given to rats, 12.7% of the dose was excreted in the
      urine as 3-hydroxycyclohexylmercapturic acid (both the cis- and trans-isomer)
      while there were only traces present of cyclohexylmercapturic acid and cis-2-
      hydroxycyclohexylmercapturic acid (but no trans-isomer). In rabbits, 3-
      hydroxycyclohexylmercapturic acid (25.4%), cyclohexylmercapturic acid
      (traces), and cis-2-hydroxycyclohexylmercapturic acid (traces) were found as
      well, in addition to glucuronides (20%) and sulphates (3.5 %). This experiment
      was mainly aimed at identifying (possible) mercapturic acid metabolites.
      Glucuronides and sulphates were not further specified and the remaining fraction
      was not accounted for (Jam71). In a separate experimented only investigating the
      possible hydroxylation at the allylic position in rats, 0.1% of an oral dose of ca.
      60 mg/kg bw was excreted as 2-cyclohexen-1-one in the 24-hour urine while no
      2-cyclohexen-1-ol (free or glucuronidated) could be detected (Lei78).
6     Effects and mechanism of action
      Human data
      The committee did not find data on workers occupationally exposed to
      cyclohexene.
      Animal data
      Irritation and sensitisation
      When 0.1 mL of cyclohexene was instilled into the right eyes of 6 rabbits, the
      mean Draize score calculated from 6 observation periods was 0.8. When the
      material was washed out after a 4-second contact period, the mean score was 0.3
      (maximum possible score: 8.0) (Moo81a, Moo81b).
          When 2 mL/kg (ca. 1600 mg/kg) was applied to the clipped skin of rabbits
      (n=3/sex) and left covered for 24 hours, erythema, oedema, and induration were
      observed in all animals, lasting for 3-5, 1, and 14 (i.e., the observation period)
      days, respectively. Eschar formation or infection were not seen in any of the
      animals (Moo81c). In guinea pigs (n=3), covered application of undiluted
      material (5-20 mL/kg) produced slight to moderate oedema, moderate to severe
100-5 Cyclohexene
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<pre>      erythema, and scattered necrosis at 24 hours, eschars over the entire patch after 1
      week, and scarring and up to complete alopecia after 2 weeks (Nob80).
          The committee did not find data on the possible sensitising effects of
      cyclohexene.
      Acute toxicity
      A 4-hour exposure to 6370 ppm (21,660 mg/m3) was not lethal to rats (n=5/sex).
      During exposure, depressed activity, ataxia, and squinting in all animals and
      lachrymation in one male animal were observed. All animals appeared normal
      within 24 hours after ending exposure. At gross necropsy at the end of the 14-day
      observation period, multiple pulmonary cysts were seen in 1/5 male and 4/5
      female animals. In one female animal, there were multiple haematomas in the
      thymus (Yat81). Single exposures of unknown duration to 8850 and 14,800 ppm
      (ca. 30,000 and 50,000 mg/m3) were stated to seriously affect and kill
      experimental animals, respectively (ACG98).
          Twenty-four-hour covered dermal application of 2 mL/kg (ca. 1600 mg/kg
      bw) to the clipped skin of rabbits (n=3/sex) did not induce mortality. Apart from
      the skin effects presented above, 2/3 male and 2/3 female animals showed
      ‘excretory conditions’ that lasted for the 14-day observation period. Both in male
      and female animals, there were weight losses in the second post-exposure
      observation week. At gross necropsy, dark purple or brown spots were seen on
      the lungs of 5 animals while discolouration of the liver and spots on the kidney
      were seen in 2 and one of these animals, respectively. The remaining 6th animal
      had spots on the kidney (Moo81c).
          In male and female rats (Sprague-Dawley), an oral LD50 of 3.53 mL/kg bw
      (ca. 2880 mg/kg bw) was found. At non-lethal doses (2.0 and 2.5 mL/kg bw, ca.
      1630 and 2040 mg/kg bw) ruffed fur, docile behaviour, tremors, and blood
      stained squinting eyes were seen, persisting throughout a significant part or the
      whole observation period. At lethal doses (3.2 and 4.0 mL/kg bw, ca. 2610 and
      3265 mg/kg bw), additional effects seen were amongst others convulsions,
      paralysis, nasal discharge, salivation, rapid breathing. The surviving animals
      from the 2 higher dose groups generally gained less weight during the
      observation period than the animals from the 2 lower dose groups. At gross
      necropsy, abnormalities were seen in the lungs, liver, and kidneys of the animals
      of all dose groups, in the stomach, intestine, and spleen of the animals of the 3
      higher dose groups, in the adrenals of the animals of the 2 higher dose groups,
      and in the thymus of the animals of the highest dose group (Moo81d). In a
      separate study, an LD50 of 2.4 mL/kg bw (ca. 1960 mg/kg bw) was found for
100-6 Health-based Reassessment of Administrative Occupational Exposure Limits
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<pre>      male rats (Charles River CD), with no mortality occurring at doses of 0.8 and 1.6
      mL/kg bw (ca. 650 and 1305 mg/kg bw). At these latter doses, depressed activity
      was observed. At necropsy, effects on the stomach, kidneys, and spleens were
      reported in some of the animals (Fie79). In male mice (Royalhart ICR), the LD50
      was calculated to be greater than 3.2 mL/kg bw (ca. 2610 mg/kg bw). No
      mortality was found at single dose of 0.2, 0.4, and 1.6 mL/kw bw (ca. 165, 325,
      and 1305 mg/kg bw), while doses of 0.8 and 3.2 mL/kg bw (ca. 650 and 2610
      mg/kg bw) caused the death of 1/4 animals in both groups. Effects observed were
      limited to the highest dose group and included depression, ataxia, and loss of
      righting reflexes, and pale kidneys in one mouse at necropsy (Fie80).
      Repeated-dose toxicity
      Information on toxicity following repeated dosing is limited to one abstract of a
      6-month inhalation study in which male rats (n=20/group), guinea pigs (n=10/
      group), and rabbits (n=6/group) were simultaneously exposed to 75, 150, 300,
      and 600 ppm (255, 510, 1020, and 2040 mg/m3), 6 hours/day, 5 days/week, for 6
      months. Examinations included body weight recordings (weekly), haematology
      (before, during, after exposure), biochemistry (after the 6-month exposure
      period), and gross pathology of the haematopoietic organs (after the 6-month
      exposure period). The rats of the highest concentration group showed
      significantly less body weight gains than the animals of the 300-ppm and the
      control group (no information on comparison with other groups given). Alkaline
      phosphatase was significantly increased in all rat exposure groups. Furthermore,
      it was stated that most of the other parameters were within normal limits for all
      groups and that there were no significant changes in the bone marrow in any of
      the exposure groups (Lah76).
          In a study designed to investigate the mechanism of the ovotoxicity induced
      in mice by 4-vinylcyclohexene, neither cyclohexene nor cyclohexene oxide
      caused ovotoxicity (parameter: follicle counts) following intraperitoneal
      injections of ca. 615 mg/kg bw and 140 mg/kg bw, respectively, for 30 days
      (Doe95). The committee did not find other data on the potential reproduction
      toxicity of cyclohexene.
      Mutagenicity and genotoxicity
      Cyclohexene was negative when tested both with and without a metabolic
      activating system (derived from induced rat livers) in S. typhimurium strains
      TA98 and TA100 (at concentrations of 2.5-2500 µg/plate - precipitation at 2500
100-7 Cyclohexene
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<pre>      µg - or 0.1-1000 µg/plate) (Flo80, Syc00) and strains TA1535 and TA1537 (250
      µg/plate) (Flo80).
7     Existing guidelines
      The current administrative occupational exposure limit (MAC) for cyclohexene
      in the Netherlands is 1015 mg/m3 (300 ppm), 8-hour TWA.
          Existing occupational exposure limits in some European countries and the
      USA are summarised in the annex.
8     Assessment of health hazard
      The committee did not find human data on effects of exposure to cyclohexene.
          Limited kinetic data suggest that cyclohexene is metabolised by cytochrome
      P450 via an epoxide intermediate. It is excreted conjugated with glutathione,
      glucuronic acid, and sulphate, depending on the species involved.
          Cyclohexene was irritating to the skin but not to the eyes of rabbits. The
      committee did not find data on potential sensitising properties.
          Based on acute lethality data, cyclohexene is of low toxicity following
      exposure by inhalation, oral administration, and by dermal contact.
          Data on repeated exposure were limited to an abstract of a 6-month
      inhalation study in rats, guinea pigs, and rabbits in which no effects were
      reported to have been induced in guinea pigs and rabbits while in rats there was a
      decrease in body weight gain in animals exposed to 2040 mg/m3 (600 ppm) and
      increased alkaline phosphatase levels in all dose groups (255-2040 mg/m3 or
      75-600 ppm). Although the significance of the latter is unclear in absence of
      histological data and 1020 mg/m3 (300 ppm) could be a NOAEL, the committee
      is of the opinion that this study cannot be used in deriving a health-based
      occupational exposure limit in view of the limited reporting and the incomplete
      post-mortem examinations (no microscopic, only partly gross examination).
      However, the committee notices that the possible NOAEL (based on decreased
      body weight gain) and the current occupational exposure limit are identical.
          The committee did not find data on the potential carcinogenicity.
          Cyclohexene did not induce mutations when tested in a bacteria cell system
      in vitro. The committee did not find data from other in vitro or in vivo assays.
          Cyclohexene was not ovotoxic in mice following intraperitoneal
      administration to mice; other data on the potential reproduction toxicity were not
      available.
100-8 Health-based Reassessment of Administrative Occupational Exposure Limits
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<pre>       The committee considers the toxicological database on cyclohexene too poor to
       justify recommendation of a health-based occupational exposure limit.
       In view of the results of a 6-month inhalation study in rats, the committee
       concludes that the current MAC-value of 1015 mg/m3 (300 ppm), 8-hour TWA,
       may be too high.
       References
ACG98  American Conference of Governmental Industrial Hygienists (ACGIH). Cyclohexene. In: TLVs® and
       other occupational exposure values - 1998 [CD-ROM]. Cincinnati OH, USA: ACGIH®, Inc, 1998.
ACG03a American Conference of Governmental Industrial Hygienists (ACGIH). Guide to occupational
       exposure values - 2003. Cincinnati OH, USA: ACGIH®, Inc, 2003: 37.
ACG03b American Conference of Governmental Industrial Hygienists (ACGIH). 2003 TLVs® and BEIs®
       based on the documentation of the Threshold Limit Values for chemical substances and physical
       agents & Biological Exposure Indices. Cincinnati OH, USA: ACGIH®, Inc, 2003: 24.
Amo83  Amoore JE, Hautala E. Odor as an aid to chemical safety: odor thresholds compared with threshold
       limit values and volatilities for 214 industrial chemicals in air and water dilution. J Appl Toxicol
       1983; 3: 272-90.
Arb02  Arbejdstilsynet. Grænseværdier for stoffer og materialer. Copenhagen, Denmark: Arbejdstilsynet,
       2002: 21 (At-vejledning C.0.1).
Can74  Canady WJ, Robinson DA, Colby HD. A partition model for hepatic cytochrome P-450-hydrocarbon
       complex formation. Biochem Pharmacol 1974; 23: 3075-8.
DFG03  Deutsche Forschungsgemeinschaft (DFG): Commission for the Investigation of Health Hazards of
       Chemical Compounds in the Work Area. List of MAK and BAT values 2003. Maximum
       concentrations and Biological Tolerance Values at the workplace Weinheim, FRG: Wiley-VCH
       Verlag GmbH & Co. KGaA, 2003: 45 (rep no 39).
Doe95  Doerr JK, Hooser SB, Smith BJ, et al. Ovarian toxicity of 4-vinylcyclohexene and related olefins in
       B6C3F1 mice: role of diepoxides. Chem Res Toxicol 1995; 8: 963-9.
EC04   European Commission: Directorate General of Employment and Social Affairs. Occupational
       exposure limits (OELs); http://europe.eu.int/comm/employment_social/h&s/areas/oels_en.htm.
Fie79  Field WE. Oral LD50 in rats. Clarks Summit PA, USA: CDC Research, Inc, 1979; study no CDC-EA-
       222-79 (available from National Technical Information Service, Springfield VA, USA; order no
       NTIS/OTS0556687).
Fie80  Field WE. Oral LD50 in mice. Clarks Summit PA, USA: CDC Research, Inc, 1980; study no CDC-
       EA-262-79 (available from National Technical Information Service, Springfield VA, USA; order no
       NTIS/OTS0556688).
Flo80  Florin I, Rutberg L, Curvall M, et al. Screening of tobacco smoke constituents for mutagenicity using
       the Ames' test. Toxicology 1980; 18: 219-32.
100-9  Cyclohexene
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<pre>HSE02  Health and Safety Executive (HSE). EH40/2002. Occupational Exposure Limits 2002. Sudbury
       (Suffolk), England: HSE Books, 2002: 15.
Jam71  James SP, Jeffery DJ, Waring RH, et al. Reaction of mono-bromo derivatives of cyclopentane,
       cyclohexane and cyloheptane and of related compounds with glutathione in vivo and the nature of the
       sulphur-containing metabolites excreted. Biochem Pharmacol 1971; 20: 897-907.
Lah76  Laham S. Inhalation toxicology of cyclohexene. Toxicol Appl Pharmacol 1976; 37: 155-6.
Lei70  Leibman KC, Ortiz E. Epoxide intermediates in microsomal oxidation of olefins to glycols. J
       Pharmacol Exp Ther 1970; 173: 242-6.
Lei71  Leibman KC, Ortiz E. Oxidation of cycloalkenes in liver microsomes. Biochem Pharmacol 1971; 20:
       232-6.
Lei78  Leibman KC, Ortiz E. Microsomal metabolism of cyclohexene. Hydroxyaltion in the allylic position.
       Drug Metab Dispos 1978; 6: 375-8.
Map93  Maples KR, Dahl AR. Levels of epoxide in blood during inhalation of alkenes and alkene oxides.
       Inhal Toxicol 1993; 5: 43-54.
Moo81a Moon RC. Primary eye irritation test (unwashed) on Phillips cyclohexene. Salt Lake City UT, USA:
       University of Utah Research Institute, 1981; rep no TR 05450-011 (available from National
       Technical Information Service, Springfield VA, USA; order no NTIS/OTS0556736).
Moo81b Moon RC. Primary eye irritation test (washed) on Phillips cyclohexene. Salt Lake City UT, USA:
       University of Utah Research Institute, 1981; rep no TR 05450-010 (available from National
       Technical Information Service, Springfield VA, USA; order no NTIS/OTS0556737).
Moo81c Moon RC. Acute dermal toxicity screen on Phillips cyclohexene. Salt Lake City UT, USA:
       University of Utah Research Institute, 1981; rep no TR 05450-007 (available from National
       Technical Information Service, Springfield VA, USA; order no NTIS/OTS0556738).
Moo81d Moon RC.Acute oral LD50 on Phillips cyclohexene. Salt Lake City UT, USA: University of Utah
       Research Institute, 1981; rep no TR 05450-022 (available from National Technical Information
       Service, Springfield VA, USA; order no NTIS/OTS0556739).
NLM03  US National Library of Medicine (NLM), ed. Cyclohexene. In: Hazardous Substances Data Bank
       (HSDB) (last revision data cyclohexene file: March 2003; last review date: September 1995); http://
       toxnet.nlm.nih.gov.
Nob80  Noble M. Toxicity report - Eastman Kodak Company - HS & HFL. Cyclohexene. 1980; available
       from National Technical Information Service, Springfield VA, USA; order no NTIS/OTS0556765.
Ort80  Ortiz de Montellano PR, Mico BA. Destruction of cytochrome P-450 by ethylene and other olefins.
       Mol Pharmacol 1980; 18: 128-35.
Swe00  Swedish National Board of Occupational Safety and Health. Occupational exposure limit values and
       measures against air contaminants. Solna, Sweden: National Board of Occupational Safety and
       Health, 2000; Ordinance AFS 2000:3.
Syc00  Sycheva LP, Zholdakova ZI, Polyakova EE, et al. Mutagenic activity of cyclohexene and products of
       its chlorination. Bull Exp Biol Med 2000; 129: 581-3.
100-10 Health-based Reassessment of Administrative Occupational Exposure Limits
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<pre>SZW03  Ministerie van Sociale Zaken en Werkgelegenheid (SZW). Nationale MAC-lijst 2003. The Hague,
       the Netherlands: Sdu, Servicecentrum Uitgevers, 2003: 22.
TRG00  TRGS 900. Grenzwerte in der Luft am Arbeitsplatz; Technische Regeln für Gefahrstoffe. BArbBl
       2000; 2.
Yat81  Yates WG, Price NH, Potter RN, et al. Acute inhalation screen on Phillips cyclohexene. Salt Lake
       City UT, USA: University of Utah Research Institute, 1981; rep no TR 05450-003 (available from
       National Technical Information Service, Springfield VA, USA; order no NTIS/OTS0555329).
100-11 Cyclohexene
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<pre>              Annex
Occupational exposure limits for cyclohexene in various countries.
country                           occupational                    time-weighted   type of          notea      referenceb
- organisation                    exposure limit                  average         exposure limit
                                  ppm           mg/m3
the Netherlands
- Ministry of Social Affairs and    300         1015              8h              administrative              SZW03
Employment
Germany
- AGS                               300         1015              8h                                          TRG00
                                  1200          4060              15 min
- DFG MAK-Kommission               -c           -c                                                            DFG03
Great Britain
- HSE                               300         1020              8h              OES                         HSE02
Sweden                              -              -                                                          Swe00
Denmark                             300         1015              8h                                          Arb02
USA
- ACGIH                             300         -                 8h              TLV                         ACG03b
- OSHA                              300         1015              8h              PEL                         ACG03a
- NIOSH                             300         1015              8h              REL                         ACG03a
European Union
- SCOEL                           -             -                                                             EC04
a
     S = skin notation; which means that skin absorption may contribute considerably to body burden; sens = substance can
     cause sensitisation.
b
     Reference to the most recent official publication of occupational exposure limits.
c
     Listed among compounds for which studies of the effects in man or experimental animals have yielded insufficient
     information for the establishment of MAK values.
100-12        Health-based Reassessment of Administrative Occupational Exposure Limits
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