<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>1,2,3-Benzotriazole
Health-based recommended occupational exposure limit
</pre>

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<pre>Aan de Minister van Volksgezondheid, Welzijn en Sport
Onderwerp       :  toezending advies over 1,2,3-benzotriazol.
Uw kenmerk      :  DGV/BMO-U-932542
Ons kenmerk     :  U 2478/AvdB/mp/459-R31
Bijlagen        :  1
Datum           :  22 november 2000
Mevrouw de Minister,
Bij brief van 3 december 1993, nr. DGV/BMO-U-932542, verzocht de Staatssecretaris
van Welzijn, Volksgezondheid en Cultuur namens de Minister van Sociale Zaken en
Werkgelegenheid om gezondheidskundige advieswaarden af te leiden ten behoeve van de
bescherming van beroepsmatig aan stoffen blootgestelde personen.
Per 1 januari 1994 heeft mijn voorganger daartoe een commissie ingesteld die de werk-
zaamheden voortzet van de Werkgroep van Deskundigen (WGD). De WGD was een
door genoemde Minister ingestelde adviescommissie.
Hierbij stuur ik u ter kennisname - gehoord de Beraadsgroep Gezondheid en Omgeving -
een publicatie van de Commissie WGD over 1,2,3-benzotriazol.
Deze publicatie heb ik heden aan de Staatssecretaris van Sociale Zaken en Werkgelegen-
heid aangeboden.
Hoogachtend,
w.g.
prof. dr JJ Sixma
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<pre>1,2,3-Benzotriazole
Health-based recommended occupational exposure limit
Dutch expert committee on occupational standards,
a Committee of the Health Council of the Netherlands
to:
the Minister and State Secretary of Social Affairs and Employment
No. 2000/14OSH, The Hague, 22 November 2000
</pre>

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<pre>The Health Council of the Netherlands, established in 1902, is an independent scientific
advisory body. Its remit is “to advise the government and Parliament on the current level
of knowledge with respect to public health issues...” (Section 21, Health Act).
     The Health Council receives most requests for advice from the ministers of Health,
Welfare & Sport, Housing, Spatial Planning & the Environment, Social Affairs &
Employment, and Agriculture, Nature Prereservation & Fisheries. The Council can
publish advisory reports on its own initiative. It usually does this in order to ask
attention for developments or trends that are thought to be relevant to government policy.
     Most Health council reports are prepared by multidisciplinary committees of Dutch
or, sometimes, foreign experts, appointed in a personal capacity. The reports are
available to the public.
Preferred citation:
Health Council of the Netherlands: Dutch expert committee on occupational standards
(DECOS). 1,2,3-Benzotriazole. The Hague: Health Council of the Netherlands, 2000;
publication no. 2000/14OSH.
all rights reserved
ISBN: 90-5549-348-1
</pre>

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<pre>    Contents
    Samenvatting en advieswaarde 7
    Executive summary 11
1   Scope 15
1.1 Background 15
1.2 Committee and method of work 15
1.3 Data 16
2   Identity, properties and monitoring 17
2.1 Identity 17
2.2 Physical and chemical properties 18
2.3 Validated analytical methods 18
3   Sources 20
3.1 Natural occurrence 20
3.2 Man-made sources 20
4   Exposure 22
4.1 General population 22
4.2 Working population 22
    Contents                               5
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<pre>5   Toxicokinetics 23
5.1 Absorption 23
5.2 Distribution 23
5.3 Biotransformation 23
5.4 Excretion 24
5.5 Biological monitoring 24
5.6 Summary 24
6   Effects 25
6.1 Observations in man 25
6.2 Animal experiments 26
6.3 Summary 35
7   Existing guidelines, standards and evaluations 36
7.1 General population 36
7.2 Working population 36
8   Hazard assessment 38
8.1 Assessment of health hazard 38
8.2 Groups at extra risk 40
8.3 Health-based recommended occupational exposure limit 40
9   Recommendations for research 41
    References 42
    Annexes 45
A   Request for advice 46
B   The committee 48
C   Comments on the public draft 50
D   Calculation of the cancer risk of benzotriazole 51
E   Abbreviations 53
    Contents                                                6
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<pre>  Samenvatting en advieswaarde
1 Vraagstelling
  Op verzoek van de Minister van Sociale Zaken en Werkgelegenheid leidt de Commissie
  WGD van de Gezondheidsraad gezondheidskundige advieswaarden af voor beroepsmati-
  ge blootstelling aan toxische stoffen in de lucht. Die afleiding is de eerste fase van een
  drietrapsprocedure die moet leiden tot wettelijke grenswaarden.
       In het voorliggende rapport bespreekt de commissie de gevolgen van blootstelling
  aan 1,2,3-benzotriazol (in het vervolg aangeduid met benzotriazol) in de lucht op de
  werkplek. De conclusies van de commissie zijn gebaseerd op wetenschappelijke publica-
  ties die vóór maart 2000 zijn verschenen.
2 Vóórkomen; fysische en chemische eigenschappen
  Benzotriazol is een reukloos, wit tot lichtbruin kristallijn poeder. Het lost matig op in
  water en goed in een aantal organische oplosmiddelen. Benzotriazol heeft een lage damp-
  spanning en zal daarom op de werkplek vooral als stof voorkomen. Stofexplosies zijn
  mogelijk, indien het in fijn verdeelde vorm gemengd wordt met lucht.
       Benzotriazol wordt gebruikt in de industrie als middel om corrosie tegen te gaan, als
  stabilisator voor plastics en als intermediair bij de synthese van andere chemische ver-
  bindingen.
  Samenvatting en advieswaarde                                                               7
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<pre>3 Monitoring
  Gezien de lage dampspanning van benzotriazol is het waarschijnlijk, dat deze verbinding
  op de werkplek alleen geadsorbeerd aan stof voorkomt. Algemene methoden voor het
  meten van inhaleerbaar stof zouden dan geschikt kunnen zijn voor het meten van ben-
  zotriazol. De fractie benzotriazol in het stof kan, na extractie met een geschikt oplosmid-
  del, analytisch chemisch worden bepaald. Gezien de specificiteit en de hoogte van de
  detectiegrens, lijken UV-spectrofotometrie of analyse met HPLC of GC-MS het meest
  geschikt.
4 Grenswaarden
  Er is geen grenswaarde voor benzotriazol vastgesteld of aanbevolen in Nederland, de
  Noord-Europese landen, het Verenigd Koninkrijk en de Verenigde Staten. In Duitsland is
  benzotriazol geplaatst op een lijst met stoffen waarvoor geen grenswaarde kon worden
  afgeleid.
5 Kinetiek
  De commissie heeft geen gegevens gevonden over de kinetiek van benzotriazol.
       Op basis van physisch chemische gegevens, mag verwacht worden, dat benzotriazol
  via de huid wordt opgenomen.
       Incubatie met rattenlevermicrosomen gedurende 1 uur resulteerde in een langzame
  omzetting in 4- en 5-hydroxybenzotriazol.
6 Effecten
  Benzotriazol veroorzaakte contactdermatitis bij metaalbewerkers na blootstelling van de
  huid.
       In onderzoek met dieren bleek benzotriazol in ernstige mate irriterend te zijn voor de
  ogen en, hooguit, in lichte mate voor de huid; een zwak sensibiliserende potentie kan niet
  worden uitgesloten. Op basis van sterfte na eenmalige blootstelling (inhalatoire LC50
  rat*: 2153 mg/m3; orale LD50 rat: 500-965 mg/kg lichaamsgewicht) en bijbehorende EG-
  richtlijnen zou benzotriazol geclassificeerd moeten worden als een stof die schadelijk is
  bij inademing en bij opname door de mond.
* Deze waarde is berekend door de commissie op basis van dierexperimentele gegevens.
  Samenvatting en advieswaarde                                                                8
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<pre>       Afgezien van orale carcinogeniteitsproeven met ratten en muizen heeft de commissie
  geen deugdelijke studies gevonden naar effecten van herhaalde blootstelling (inbegrepen
  reproductie-studies).
       In de carcinogeniteitsstudies werden hogere incidenties van — meestal goedaardige
  — tumoren gevonden bij behandelde dieren dan bij controles. Deze incidenties waren
  meestal hoger bij de lage dan bij de hoge doseringsgroep en de achtergrondincidenties bij
  de controledieren waren hoog. De commissie kon geen NOAEL vaststellen, aangezien bij
  de laagste dosering nog effecten werden gezien. De LOAELs werden vastgesteld op 295
  en 1455 mg/kg lichaamsgewicht per dag bij respectievelijk ratten en muizen.
       In in vitro onderzoek was benzotriazol mutageen in S. typhimurium en in E. coli,
  maar niet in CHO-cellen (’Chinese hamster ovary’ cellen). Een test waarin DNA-schade
  in vitro werd bepaald was ook negatief. Na orale blootstelling van muizen aan benzotria-
  zol was de in vivo (beenmerg) micronucleus test eveneens negatief.
7 Evaluatie
  Op basis van humane en/of dierexperimentele gegevens concludeert de commissie, dat
  sensibilisering en oogirritatie als gevolg van beroepsmatige blootstelling aan benzotriazol
  niet kunnen worden uitgesloten.
       Op basis van de carcinogeniteitsstudies met ratten en muizen concludeert de com-
  missie, dat er onvoldoende bewijs is voor de carcinogeniteit van benzotriazol. Hoewel in
  enkele organen hogere incidenties van — meestal goedaardige — tumoren werden aange-
  troffen bij behandelde dieren dan bij de controles, waren deze incidenties meestal hoger
  bij de lage dan bij de hoge doseringsgroep en waren de achtergrondincidenties bij histori-
  sche controledieren hoog.
       Omdat er onvoldoende bewijs is voor carcinogene potentie van benzotriazol bij
  knaagdieren engezien de mutagene effecten van benzotriazol in bacteriële systemen maar
  het ontbreken van in vitro genotoxiciteitstesten met zoogdiercellen en in vivo genotoxici-
  teitsonderzoek bij proefdieren, is de commissie van mening, dat de gegevens te mager
  zijn om een conclusie te rechtvaardigen met betrekking tot de carcinogeniteit en mutage-
  niteit van benzotriazol. De gegevens zijn onvoldoende om benzotriazol te classificeren
  als een stof die als kankerverwekkend voor de mens beschouwd moet worden, maar ge-
  ven wel reden tot bezorgdheid. 1,2,3-Benzotriazol wordt dan ook geclassificeerd als ver-
  dacht carcinogeen.
       Wanneer de commissie er van uit zou gaan, dat benzotriazol geen carcinogene eigen-
  schappen bezit, dan zouden de beschikbare orale gegevens gebruikt kunnen worden om
  een gezondheidskundige advieswaarde af te leiden. De “lowest-observed-adverse-effect
  level” van 295 mg/kg lg/d uit de chronische rattenstudie zou als uitgangspunt gebruikt
  kunnen worden. Het zal duidelijk zijn, dat extrapolatie vanuit deze orale dosis die bij
  Samenvatting en advieswaarde                                                                9
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<pre>  proefdieren nog effect veroorzaakt, met toepassing van de gebruikelijke overwegingen en
  aannames, zal leiden tot een gezondheidskundige advieswaarde die aanzienlijk hoger is
  dan de maximaal aanvaarde concentraties die in Nederland zijn vastgesteld voor respira-
  bel en inhaleerbaar hinderlijk stof, namelijk respectievelijk 5 en 10 mg/m3. Omdat ben-
  zotriazol bij kamertemperatuur op de werkplek voor zal komen als stof, zouden deze
  waarden van toepassing zijn.
       Omdat het echter niet uitgesloten kan worden, dat benzotriazol een genotoxisch car-
  cinogeen is, achtte de commissie het wenselijk om het kankerrisico te berekenen dat sa-
  menhangt met een beroepsmatige blootstelling aan 10 mg/m3. Op basis van een “worst
  case” benadering (zie Annex) zou beroepsmatige blootstelling aan 10 mg/m3 gedurende
  40 jaar gepaard gaan met een extra kans op overlijden als gevolg van kanker van 5 per
  10.000.
       Voorts is gebleken, dat benzotriazol ernstige oogirritatie veroorzaakt bij proefdieren.
  Dit zou kunnen betekenen, dat irritatie van de ogen en/of de luchtwegen of zelfs ernstige-
  re effecten op deze orgaansystemen van werkers blootgesteld aan benzotriazolconcentra-
  ties van 5 mg/m3 als respirabele en van 10 mg/m3 als inhaleerbare deeltjes kunnen
  optreden, of in ieder geval niet uitgesloten kunnen worden. Omdat er geen humane gege-
  vens betreffende oogirritatie beschikbaar zijn en toxiciteitsstudies waarin proefdieren
  herhaaldelijk inhalatoir zijn blootgesteld, ontbreken, concludeert de commissie, dat het
  niet mogelijk is om op basis van de beschikbare gegevens een gezondheidskundige ad-
  vieswaarde af te leiden.
8 Gezondheidskundige advieswaarde
  De Commissie WGD van de Gezondheidsraad concludeert, dat de beschikbare toxicolo-
  gische gegevens over benzotriazol onvoldoende zijn voor het afleiden van een gezond-
  heidskundige advieswaarde.
  De commissie classificeert 1,2,3-benzotriazol als verdacht carcinogeen.
  Samenvatting en advieswaarde                                                                 10
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<pre>  Executive summary
1 Scope
  At the request of the Minister of Social Affairs and Employment, the Health Council of
  the Netherlands recommends health-based occupational exposure limits for the
  concentration of toxic substances in air at the workplace. These recommendations are
  made by the Council’s Dutch Expert Committee on Occupational Standards. They con-
  stitute the first step in a three-step procedure that leads to legally-binding limit values.
        In the present report, the committee discusses the consequences of occupational ex-
  posure to 1,2,3-benzotriazole (further referred to as benzotriazole) and, if appropriate,
  recommends a health-based occupational exposure limit. The committee’s conclusions
  are based on scientific publications prior to March 2000.
2 Occurrence, physical and chemical properties
  Benzotriazole is an odourless, white to tannish crystalline powder. It is sparingly soluble
  in water and soluble in a number of organic solvents. It has a low vapour pressure, and
  it is therefore likely to occur as dust at the workplace. When finely divided and mixed
  with air, dust explosions may occur.
        Benzotriazole is an industrial compound primarily used as a corrosion inhibitor, as a
  plastic stabilizer, and as a chemical intermediate.
  Executive summary                                                                            11
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<pre>3 Monitoring
  In view of the low vapour pressure at room temperature, it is likely that benzotriazole
  will only occur as dust at the workplace. A general method for measuring inhalable dust
  should than be suitable for measuring benzotriazole. The benzotriazole content in the
  dust may be assessed by analytical-chemical methods after extraction with a suitable
  solvent. In view of the specificity and the height of the detection limit, UV-spectrophoto-
  metry or a HPLC or GC-MS method may be most appropriate.
4 Limit values
  No occupational exposure limits/standards for benzotriazole have been established or re-
  commended in the Netherlands, the Nordic countries, the UK, and the USA (ACGIH). In
  Germany, benzotriazole was listed among the compounds for which no limit could be es-
  tablished.
5 Kinetics
  The committee did not find data on the toxicokinetics of benzotriazole. Based on physi-
  co-chemical data, dermal absorption might be expected. In an in vitro experiment using
  rat liver microsomes and a one-hour incubation period, it was metabolized to 4- and
  5-hydroxybenzotriazole at a low rate.
6 Effects
  In metal workers, contact dermatitis was observed after skin exposure to benzotriazole.
       In experimental animals, benzotriazole appeared to be a severe eye irritant and, at
  most, a slight skin irritant; Benzotriazole is not a skin sensitizer. Based on acute letal
  toxicity data (inhalation LC50 rat*: 2153 mg/m3; oral LD50 rat: 500-965 mg/kg bw) and
  using EC-classification criteria, benzotriazole should be classified as harmful following
  inhalation and oral exposure.
       Apart from oral carcinogenicity studies in rats and mice, the committee did not find
  data from valid repeated-dose toxicity (including developmental toxicity) studies.
       In the carcinogenicity studies, higher incidences of — mostly benign — tumours in
  some organs were observed in treated than in concurrent control animals. These tumours
  had mostly higher incidences in the low-dose than in the high-dose group, and occurred
* Calculated by the committee.
  Executive summary                                                                           12
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<pre>  at fairly high rates in historical controls. The committee could not assess a NOAEL sin-
  ce several effects were observed at the lowest dose tested. The LOAELs were set at 295
  and 1455 mg/kg bw/day in rats and mice, respectively.
       Benzotriazole is, in vitro, mutagenic in S. typhimurium TA 1535 and in E. coli, but
  not in chinese hamster ovary cells. The SOS chromotest in E. coli, an indicator test for
  DNA damage was negative. In vivo, benzotriazole was negative in an oral mouse bone
  marrow micronucleus assay.
7 Hazard assessment
  Based on the human and/or experimental animal data, the committee concludes that eye
  irritation following occupational exposure to benzotriazole cannot be excluded.
       From the carcinogenicity studies with rats and mice, the committee concludes that
  there is inconclusive evidence that benzotriazole is carcinogenic. Although higher inci-
  dences of — mostly benign — tumours in some organs were observed in treated than in
  concurrent control animals, these tumours had mostly higher incidences in the low-dose
  than in the high-dose group, and occurred at fairly high rates in historical controls.
       In view of the inconclusive evidence for carcinogenic potential of benzotriazole in
  rodents and the mutagenic effects of benzotriazole in bacterial systems along with the
  absence of mutagenic and genotoxic effects in vitro in mammalian cells and in vivo in
  experimental animals, the committee considers the data base too poor to justify a conclu-
  sion regarding genotoxicity and carcinogenicity of this chemical. Clearly, the data base
  is inadequate to classify benzotriazole as a probable carcinogen to humans, but it may
  raise concern for humans. Therefore, 1,2,3-benzotriazole is classified as a suspect carci-
  nogen.
       Assuming — for the time being — benzotriazole does not possess carcinogenic pro-
  perties, one might use the available oral data to derive an occupational exposure limit.
  The LOAEL of 295 mg/kg bw/d from the chronic rat study could be used as a starting
  point. It will be clear that extrapolation from this LOAEL applying the usual considera-
  tions and assumptions will lead to a limit value much higher than the maximum accepted
  concentrations set in the Netherlands for respirable and inhalable nuisance dust, viz, 5
  and 10 mg/m3, respectively. Since benzotriazole at room temperature will be present at
  the workplace as dust, these values could then be applied as occupational exposure li-
  mits for benzotriazole.
       Since, however, it cannot be excluded that benzotriazole is a genotoxic carcinogen,
  the committee deemed it desirable to calculate the cancer risk associated with an occupa-
  tional exposure level of 10 mg/m3. Using a “worst-case” approach (see Annex), occupa-
  tional exposure to 10 mg/m3 for 40 years should be associated with an excess cancer
  mortality risk of 5 per 10.000.
  Executive summary                                                                          13
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<pre>       Furthermore, benzotriazole appeared to be a slight eye irritant in experimental ani-
  mals. This may indicate that eye and/or respiratory tract irritation can not be excluded to
  occur in workers exposed to benzotriazole concentrations of 5 mg/m3 for respirable par-
  ticles and to 10 mg/m3 for inhalable ones. Since no eye irritation studies in humans were
  available and repeated-dose inhalation toxicity studies in experimental animals were ab-
  sent, the committee concludes that it is not justifiable to derive a health-based occupatio-
  nal exposure limit from the available data.
8 Health-based recommended occupational exposure limit
  The Dutch Expert Committee on Occupational Standards considered the data base on
  benzotriazole too poor to justify recommendation of a health-based occupational exposu-
  re limit.
  The committee classifies 1,2,3-benzotriazole as a suspected human carcinogen.
  Executive summary                                                                            14
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<pre>Chapter 1
        Scope
1.1     Background
        In the Netherlands, occupational exposure limits for chemical substances are set using a
        three-step procedure. In the first step, a scientific evaluation of the data on the toxicity of
        the substance is made by the Dutch Expert Committee on Occupational Standards (DE-
        COS), a committee of the Health Council of the Netherlands, on request of the Minister
        of Social Affairs and Employment (Annex A). This evaluation should lead to a health-
        based recommended exposure limit for the concentration of the substance in air. Such an
        exposure limit cannot be derived, if sufficient data are not available or if the toxic action
        cannot be evaluated using a threshold model. In the latter case, an exposure-response re-
        lationship is recommended for use in regulatory standard setting.
             In the next phase of the three-step procedure, the Social and Economic Council advi-
        ses the Minister on feasibility of using the health based value as a regulatory Occupatio-
        nal Exposure Limit (OEL), or recommends a different OEL. In the final step of the
        procedure, the Minister of Social Affairs and Employment sets the official Occupational
        Exposure Limit.
1.2     Committee and method of work
        This document is a co-production of DECOS and the Nordic Expert Group for Docu-
        mentation of Occupational Exposure Limits (NEG). It is a result of an agreement bet-
        ween both groups to prepare jointly criteria documents which can be used by the
        Scope                                                                                           15
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<pre>    regulatory authorities in the Netherlands and in the Nordic countries. The draft docu-
    ment has been prepared by H. Stouten, A.A.J.J.L. Rutten, I.A. van de Gevel, and F. de
    Vrijer from the Toxicology Division of TNO Nutrition and Food Research, Zeist, the
    Netherlands, and was first reviewed by DECOS and thereafter by NEG.
        In 1999, the President of the Health Council released a draft of the report for public
    review. The individuals and organizations that commented on the draft are listed in An-
    nex C. The committee has taken these comments into account in deciding on the final
    version of the report.
1.3 Data
    For the preparation of this document, literature has been retrieved from online data bases
    such as Medline, Toxline and CA (last update online search: May 1998). HSDB and
    RTECS, data bases available from CD-ROM, were consulted as well (NIO00, NLM00).
        Before finalizing the document, the committee performed an additional literature
    search in Medline (May 1998 - August 2000) and Toxline (May 1998 - April 2000).
    The results of this search were no reason for the committee to adjust the recommenda-
    tions.
    Scope                                                                                      16
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<pre>Chapter 2
        Identity, properties and monitoring
2.1     Identity
2.1.1   Structure
2.1.2   Chemical names and synonyms/registry numbers
         Name                      :    benzotriazole
         CAS registry number       :    95-14-7
         CAS index name            :    1H-benzotriazole
         Synonyms 2,3-diazaindole  :    1,2,3-benzotriazole; benzisotriazole; benztriazole;
                                        1,2-amino-azophenylene; azimidobenzene; aziminobenzene; ben-
                                        zene azimide; 2,3-diazaindole; 1,2,3-triaza-1H-indene;
                                        1,2,3-triazaindene; benzene azimide; 2,3-diazaindole
         EINECS No                 :    202-394-1
         RTECS No                  :    DM1225000
        Identity, properties and monitoring                                                          17
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<pre>2.2   Physical and chemical properties (Che99, Dav77, Han95, NLM00)
       Molecular formula                 :  C6H5N3
       Molecular weight                  :  119.14
       Boiling point (101.3 kPa)         :  350 ºC
       Melting point (101.3 kPa)         :  99 ºC
       Relative density (water=1)        :  1.4
       Vapour density (air=1)            :  4.1
       Vapour pressure                   :  < 0.01 kPa
        (20 ºC; 101.3 kPa)
       Relative density of saturated     :  1.00
       vapour/air mixture (air=1; 20 ºC)
       Auto-ignition temperature         :  400 ºC
       Explosive limits (%, in air)      :  2.4-?
       Solubility in water (25 ºC)       :  2.0 g/100 ml
       Solubility in organic solvents    :  soluble in alcohol, benzene, toluene, chloroform, dime-
                                            thylformamide
       Log Poctanol/water                :  1.44 (experimental value)
       Physical form                     :  white to tan, crystalline powder; needles when crystallized
                                            from benzene
       Odour                             :  odourless
      Benzotriazole exists in two tautomeric forms. The first tautomer has the formula
      1H-benzotriazole. The second tautomer has the formula 2H-benzotriazole and is also re-
      ferred to as pseudo-azimidobenzene or 2,1,3-benzotriazole. The 1H-tautomer represents
      the more stable and essentially exclusive molecular structure (Dav77).
            Dust explosions can occur when finely divided powder is mixed with air. It can ex-
      plode when heated and during vacuum distillation. When heated or combusted, benzotri-
      azole decomposes into toxic vapours (nitrogen dioxide). It is very stable toward acids
      and alkalies, and toward oxidation and reduction.
2.3   Validated analytical methods
2.3.1 Environmental monitoring
      No method for monitoring benzotriazole in air was available. However, since benzotria-
      zole will hardly vaporize at room temperature, it will be present as dust, and general dust
      Identity, properties and monitoring                                                               18
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<pre>      measurement methods should be applicable (for overview: see Bol95). The benzotriazole
      content in the dust may be assessed by analytical-chemical methods after extraction with
      a suitable solvent. In view of the specificity and the height of the detection limit, UV-
      spectrophotometry or a HPLC or GC-MS method may be most appropriate (see Section
      2.3.2).
2.3.2 Biological monitoring
      No method for the determination of benzotriazole in biological samples was found.
          GC-MS, HPLC, and spectrophotometric methods for the determination of benzotria-
      zole in aqueous solutions have been published (Dav77, Haw81).
          No validated method for biological monitoring of workers exposed to benzotriazole
      was found.
      Identity, properties and monitoring                                                       19
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<pre>Chapter 3
        Sources
3.1     Natural occurrence
        No data available.
3.2     Man-made sources
        No data available.
3.2.1   Production
        Benzotriazole is produced by reaction of o-phenylenediamine with nitrous acid in the
        presence of glacial acetic acid or by reaction of hydrochloric acid or nitrous acid with o-
        phenylenediamine. The production of benzotriazole in the US was mentioned to be pro-
        bably higher than approximately 7 and 4.5 tonnes in 1977 and 1979, respectively
        (NLM00).
3.2.2   Uses
        Benzotriazole is used as a corrosion inhibitor, as a plastic stabilizer, and as a chemical
        intermediate for dyes, pharmaceuticals, and fungicides. Derivates of benzotriazole are
        used as UV absorbers and as restrainers in photographic emulsions (NLM00).
        Sources                                                                                     20
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<pre>     Benzotriazole is used in metal working and in art restoration as an anticorrosive, and
in the construction industry as a tarnish remover and a protective coating of metal. It
functions as a corrosion inhibitor in water cooling systems such as automobile radiators
and boilers, and in dry cleaning equipment. It is included in some formulations of auto-
matic dishwater detergents to prevent tarnishing of metal pots and silverware, and to in-
hibit the corrosion of metal machine parts. Benzotriazole is used in synthetic greases,
lubricants, and hydraulic fluids to prevent the oxidation of these materials which is cata-
lyzed by metal ions. In the electronics industry, it is used to treat packing materials for
copper electronic parts, and to extend the life of polymers that are used as insulators for
copper wire. Furthermore, benzotriazole is used in electrolytic processing, where the
stripping of metals from copper cathodes is eased by pretreatment of the cathode with
benzotriazole. In photographic processing, benzotriazole acts as an antifogging agent in
silver-halide emulsions, restraining the developer and preventing the blackening or fog-
ging of the image due to overdevelopment (NCI78).
Coolant lubricants and corrosion inhibiting fluids may contain up to 0.05% benzotriazo-
le (Gre99, Mau84).
Sources                                                                                     21
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<pre>Chapter 4
        Exposure
4.1     General population
        No data available.
4.2     Working population
        No data available.
        Exposure           22
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<pre>Chapter 5
        Toxicokinetics
        There is very little information found with respect to the toxicokinetics of benzotriazole.
5.1     Absorption
        Based on its molecular weight (119.14) and its partition coefficient (log Poctanol/water), der-
        mal absorption might be expected.
            Because benzotriazole is a weak base (pK=1.6) as well as a weak acid (pKa = 8.57)
        (Alb48), a low degree of ionization of benzotriazole can be predicted at the physiological
        pHs of stomach, intestine, and blood, suggesting that it would easily pass the respective
        membranes. It is, however, noticed that other factors than passive diffusion play a role in
        passing membranes.
5.2     Distribution
        No information available.
5.3     Biotransformation
        Benzotriazole was incubated for one hour with a microsome suspension obtained from
        phenobarbital-induced rat livers at a final concentration in the incubation solution of 0.2
        mg/ml. During this one-hour incubation period, the overall metabolism of benzotriazole
        was relatively low (<5% of the amount added to incubation mixture), and the 5-hydroxy
        Toxicokinetics                                                                                  23
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<pre>    metabolite of benzotriazole was formed 4-5 times more than 4-hydroxybenzotriazole
    (1.6 vs 0.32% of the amount added) (Hof82).
5.4 Excretion
    No information available.
5.5 Biological monitoring
    No information available.
5.6 Summary
    The committee did not find information on distribution, excretion, and biological monito-
    ring. Based on physico-chemical data (molecular weight, partition coefficient), dermal
    absorption might be expected. In vitro using a rat liver microsomal suspension and an
    incubation period of one hour, benzotriazole is metabolized to 4- and
    5-hydroxybenzotriazole at a low rate.
    Toxicokinetics                                                                            24
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<pre>Chapter 6
        Effects
6.1     Observations in man
6.1.1   Irritation and sensitization
        Four cases of contact dermatitis among workers exposed to benzotriazole-containing in-
        dustrial oils or greases showed positive reactions (varying from weakly to strongly posi-
        tive) in a patch test using 2% benzotriazole in petrolatum (Duc80). However, since there
        were no data on negative controls and an immunological reaction was not ascertained,
        the committee can not assess whether the effects were the consequence of either irritation
        or sensitization.
              Forty out of 286 workers from ten Dutch metalworking factories had contact derma-
        titis of the hands and/or forearms. Benzotriazole was not listed among the compounds
        that induced contact allergy in eight out of these 40 workers upon patch-testing (Boe89).
        Conclusion
        Based on the available data on humans, an irritating and/or sensitizing potential of ben-
        zotriazole cannot be excluded.
6.1.2   Toxicity due to experimental or occupational exposure
        No data available.
        Effects                                                                                    25
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<pre>6.2   Animal experiments
6.2.1 Irritation and sensitization
      Eye
      Referring to unpublished industrial reports from the mid 1970s, it was stated that 100
      mg of benzotriazole instilled into one eye of rabbits (n=6) produced severe irritation,
      amongst others complete corneal opacity and severe chemosis (swelling of lids) in four
      animals. Immediate washing with water greatly reduced the irritation (BIB95, Dav77).
            In an unpublished study, benzotriazole (granules; “Preventol CI-8”; purity (from
      Hei88): 99.83%) was slightly irritating to the eyes of female albino rabbits (HC:NZW;
      n=3). The study was performed to corresponding OECD and EU guidelines. When 100
      µl of the test substance was instilled into the rabbit’s eye, left there for 24 hours before
      washing out, the following Draize scores were obtained (Ruf87):
       scoresa observed after:              1 hour        24 hours       48 hours       72 hours         7 days
       cornea
             opacity                        1,1,1         1,1,1          1,0,1          0,0,0            0,0,0
       iris                                 1,1,0         1,0,0          1,0,0          0,0,0            0,0,0
       conjunctivae
             redness                        1,1,1         1,1,2          2,1,2          1,0,1            0,0,0
             chemosis                       2,2,3         1,2,1          1,0,0          0,0,0            0,0,0
             discharge                      2,2,2         2,2,0          1,0,0          0,0,0            0,0,0
       a
             figures are irritation scores per animal. Grades for scoring range from 0-2 for iris, 0-3 for conjunc-
             tival redness and from 0-4 for corneal opacity and conjuctival chemosis and discharge.
      Skin
      In an unpublished study, benzotriazole (granules; “Preventol CI-8”; purity (from Hei88):
      99.83%) was not irritating to the skin of female albino rabbits (HC:NZW; n=3). The
      study was performed to corresponding OECD and EU guidelines. No erythema or oede-
      ma — all scores were 0 — was observed when 500 mg test material (vehiculum: water)
      was applied under semi-occlusive conditions for four hours to the intact clipped skin
      (observation times: 1, 24, 48, and 72 hours and 7 and 14 days) (Ruf87).
            Benzotriazole and commercial benzotriazole (purity: unknown) were only minimally
      irritating (primary irritation index: 1.0, 0.7, respectively; maximum score: 8.0) when ap-
      plied to the abraded and intact, clipped skin (under 24-hours occlusion) of New Zealand
      Effects                                                                                                       26
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<pre>white rabbits (n=3/sex) at a concentration of 50% in polyethylene glycol (PEG 400) and
saline (70:30) (Cib93a, Cib93d).
     Referring to unpublished industrial reports from the mid 1970s, it was mentioned
that benzotriazole was mildly irritating to guinea-pigs at a concentration of 50% in etha-
nol. Furthermore, in a separate experiment, no irritation was reported after 24 and 72
hours (no other evaluation time points mentioned) when about 80 mg/cm2 (of the pure
material) was administered to the intact or abraded skin of rabbits (n=6/group) and co-
vered for 24 hours. However, there were signs of irritation, consisting of a well defined
but transient erythema observed at experimental day 2, in three out of five rabbits follo-
wing 24-hour covered contact with 2000 mg/kg bw applied to abraded skin (observation
period: 14 days) (Dav77, BIB95).
Sensitization
In an unpublished study, benzotriazole (“Benzotriazol Granulat”/“Preventol CI-8”; puri-
ty: 99.83%) was not a skin sensitizer when tested in male guinea pigs (Winkelmann
DHPW; n=20; controls: n=10) using the Magnusson-Kligman maximization test. The
study was performed according to corresponding OECD and EU guidelines (GLP state-
ments were included). A positive control group treated with formaldehyde was included
to demonstrate the sensitivity of the test. Following an intradermal and topical (one week
later) induction of a 5 and 25 % solution in propylene glycol, respectively, an epidermal
challenge application of a 12% solution, three weeks later, caused a positive reaction in
1/20 animals. This positive response was, however, very weak. It was observed only 24
hours after challenge and not confirmed by the 48-hour observation. In the control
group, a weak positive response was found 1/10 animals at the 24-hour observation
(Hei88).
     In guinea pigs, the optimization test showed negative results with purified and com-
mercial (purity: unknown) benzotriazole after intradermal as well as epidermal challenge
application. In the maximization test, negative results were obtained with purified ben-
zotriazole (exact composition not known), but an epidermal challenge application of
30% of commercial benzotriazole caused slight erythemas in 3/20 animals (controls:
0/19) (Mau84). In two other, not published studies (industrial reports from the mid
1970s), it was reported not to be a skin sensitizer when tested in guinea-pigs (no experi-
mental details presented) (BIB95).
Conclusion
From data with benzotriazole of known purity, the committee concludes that, in experi-
mental animals, the compound is slightly irritating to the eyes and, at most, slightly irri-
Effects                                                                                      27
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<pre>      tating to the skin. In addition, the committee is of the opinion that benzotriazole is not a
      skin sensitizer.
6.2.2 Acute toxicity
      When rats (male; n=10/group) were inhalatory exposed during three hours to benzotria-
      zole aerosols of 780, 1460, 2030, 2230, and 2710 mg/m3 (no data on particle size, parti-
      cle size distribution humidity, etc), mortality was 10%, 20%, 50%, and 100%
      respectively. Almost all animals died during the exposure period, usually during the first
      half hours, and showed severe accumulation of white frothy liquid in the trachea and
      haemorrhages in the lungs. There was no pulmonary oedema. In the surviving animals,
      the only sign of intoxication observed was deep abdominal breathing and open mouth
      gasping in the animals exposed to the two highest concentrations. From these mortality
      data, an LC50 of 1910 mg/m3 (95% CI: 1590-2290 mg/m3) was presented (see BIB95,
      Dav77). [The committee is of the opinion that in view of the experimental data, this LC50
      of 1910 mg/m3 is rather unlikely. From the same data the committee concluded that an
      LC50 of 2153 mg/m3 (95% CI: 1908-2402 mg/m3) seems more reasonable.]
      Dermal LD50 values were reported to be greater than 1000 and 2000 mg/kg bw in rats
      (NIO00) and rabbits (BIB95), respectively. Only the rabbit study was described in more
      detail. Apart from skin irritation (see also Section 6.2.1), no other toxic effects were re-
      ported. However, histological examinations were not included, and the absence of a con-
      trol group prevented the evaluation of body weight gain data (Dav77).
           Oral LD50 values ranged from 500 to 965 mg/kg/bw in rats, whereas in mice oral
      LD50s of 615 (NIO00), 831 (Gre99) and greater than 4500 mg/kg bw (BIB95) have been
      mentioned. In guinea pigs, it was estimated at 500 mg/kg bw (NIO98). No description of
      toxic effects was given. In a range-finding toxicity test preceding an unpublished micro-
      nucleus test (see also section 6.2.5), single oral (gavage) doses of 500, 750, 850, and
      1000 mg/kg bw of benzotriazole (granules; “Preventol CI8-100”; purity: 99.83%) to
      groups of, a total of, five mice (Bor:NMRI; both males and females included) caused
      mortality in the two higher dose groups (850 mg/kg: 2/5; 1000 mg/kg: 3/5). Symptoms
      observed included apathy, reduced motility, unkempt coat, lateral position, abdominal
      position, cramp, convulsion, and rapid breathing. Data relating incidence/severity and
      dose levels were not given (Her88).
           Ip LD50 values ranged from 500-900 and 500-1000 mg/kg bw in rats and mice, res-
      pectively. In mice, effects on the central nervous system (convulsions; flaccid paralysis)
      were seen at doses of approximately 250 mg/kg bw. Following single iv injections to
      mice, a LD50 was found to be 238 mg/kg bw, while effects on the central nervous system
      Effects                                                                                      28
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<pre>      (reduced reflexes; paralysis) were observed at a dose of 55 mg/kg bw. In mice, iv and ip
      doses caused death by respiratory arrest (BIB95).
      Conclusion
      Based on the acute lethal toxicity data (inhalation LC50 rat*: 2153 mg/m3; oral LD50 rat:
      500-965 mg/kg) and using EC-classification criteria, the committee concludes that ben-
      zotriazole is harmful following inhalation and oral exposure. Oral and ip LD50s in rats
      and mice were of similar order of magnitude (500-1000 mg/kg bw).
6.2.3 Short-term toxicity (up to 90 days)
      In a pilot experiment prior to a carcinogenicity study, groups of male (5) and female (5)
      rats (Fischer 344) and mice (B6C3F1) were fed benzotriazole at concentrations of 300,
      1000, 3000, 10,000, and 30,000 ppm (rats: approx 13-1325 mg/kg bw/d; mice: approx
      37-3710 mg/kg bw/d)** in the diet for eight weeks. This experiment was performed in
      order to estimate the maximum tolerated dose. It was not reported which end points were
      investigated, and only statements on survival and body weight were presented. In rats,
      body weight decreases*** were not higher than 12% at each dose ranging from 300 to
      10,000 ppm, while a sharp decrease of 34-40% in body weight was observed at 30,000
      ppm. All animals survived. In mice, a small effect on body weight (i.e., a decrease of ap-
      prox 5%) was observed at a concentration of 30,000 ppm only (NCI78). However, con-
      sidering the low number of animals used and the limited scope (range-finding for a 2-y
      carcinogenicity study) and reporting (only statements on survival and body weight), no
      conclusions regarding a NOAEL can be drawn from this study.
           Undefined toxic effects on the peripheral blood system, liver, and kidney were obser-
      ved in rats (sexe not known) after oral administration of 2.4, 12, and 60 mg/kg bw/day
      for 30 days. A daily oral dose of 0.6 mg/kg bw for six months induced toxic effects (not
      specified), while 0.06 mg/kg bw/d did not (original paper in Russian). No further details
      were reported (Gre99), and therefore this study is not suitable for evaluation of the he-
      alth hazard.
*     This value was calculated by the committee from the experimental data presented in BIB95 and Dav77 (see section
      6.2.2)
**    To convert oral doses from ppm or mg/kg diet into mg/kg bw the following default values (or their averages) are used
      throughout this report: rat male: bw 500 g, daily food intake: 20 g; female: bw: 350 g, daily food intake: 17.5 g; mouse
      male: 30 g, daily food intake: 3.6 g; female: bw 25 g, daily food intake: 3.25 g.
***   Probably decreased body weight gain was meant
      Effects                                                                                                               29
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<pre>      Conclusion
      The available short-term toxicity studies suffered from various limitations excluding
      them from being used for health hazard assessment purposes.
6.2.4 Long-term toxicity and carcinogenicity
      In a carcinogenicity study, male and female rats (Fischer 344; n=50/sex/group) were fed
      time-weighted average doses of 6700 and 12,100 ppm (i.e., approx 295 and 535 mg/kg
      bw/d; dosage adjusted during the experimental period) for 78 weeks. This was followed
      by an observation period of 27 weeks. Animals were observed twice daily for signs of
      toxicity, clinical observations were recorded every month, and body weights were recor-
      ded every two weeks for the first twelve weeks and every month thereafter. The patholo-
      gical evaluation consisted of gross and microscopical examinations of major tissues,
      major organs, and all gross lesions from killed animals and from animals found dead.
      Data on both neoplastic and nonneoplastic lesions were presented. No data on organ
      weights were given. Consistently lower mean body weights were found in the exposed
      groups when compared with controls (only growth curves presented). In male rats, sur-
      vival rates were not affected by treatment, while in dosed females survival was slightly
      higher than in controls. No compound-related clinical signs were seen. At post-mortem
      examinations, nonneoplastic lesions observed were: inflammation of the prostate and the
      uterus and changes in the liver (“clear-cell changes”, “basophilic cytoplasm change”,
      “eosinophilic cytoplasm change”).
           With respect to neoplastic lesions, benign liver tumours (nodules), not present in ei-
      ther the control or low-dose male rats, were seen in five out of the 45 (11%) high-dose
      males, a statistically significant increase. However, since incidences of 10-11% had been
      seen in two out of thirteen groups of untreated rats of the same strain at the same labora-
      tory (in previous experiments), the investigators concluded that the tumours “cannot be
      clearly associated with administration of the test chemical”. There were brain tumours in
      three out of the 44 (7%) low-dose males and in one out of the 50 (2%) high-dose fema-
      les, but neither in male nor in female controls. Previous results, from the same laborato-
      ry, showed a low incidence of brain tumours in untreated rats of the same strain (none in
      250 males and one in 249 females studied). The investigators concluded that the tumours
      were “suggestive of, but not considered as sufficient evidence of, carcinogenicity”. The
      low-dose females had a significantly higher level of benign uterus tumours compared
      with the controls (10/45 or 22% vs 2/48 or 4%). However, since the 16% incidence in
      the high-dose group did not attain statistical significance, the investigators concluded
      that these tumours “cannot be associated with administration of the chemical” (NCI78).
      In addition, incidences of 12-15% had been seen in untreated groups of the same strain
      Effects                                                                                     30
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<pre>of rat in other laboratories (BIB95). Benign thyroid tumours were seen in four out of the
43 (9%) low-dose female rats while malignant thyroid tumours occurred in one out of
the 43 (2%) low-dose and three out of the 50 (6%) high-dose females. These tumours
were not present in the female controls (NCI78). Previous results, in other laboratories
(again with the same strain), have shown the incidence of these types of benign and ma-
lignant thyroid tumours in untreated female groups to be 4-5% and 1-4%, respectively
(BIB95). The above results, therefore, may indicate a weak carcinogenic action at this
site, although the investigators do not discuss these findings. There was no statistically
significant increase in thyroid tumour incidence in the male rats (NCI78).
     A similar carcinogenicity study was performed in mice (B6C3F1; n=50/sex/group)
according to a similar protocol. When fed average time-weighted doses of 11,700 and
23,500 ppm (i.e., ~1455 and ~2925 mg/kg bw/d; dosage adjusted during the experimen-
tal period) for 104 weeks followed by an observation period of two weeks, mean body
weights were dosis-relatedly decreased (only growth curves presented). As in rats, sur-
vival rates were affected in dosed females (i.e., higher) only, and there were no clinical
signs. Treatment-induced nonneoplastic changes were found in the bone marrow (myelo-
fibrosis) and mesenteric lymph nodes (haemorrhages). No convincing evidence of carci-
nogenicity was seen. However, a higher number of lung tumours were found in the
treated females; incidences in the controls, low-dose, and high-dose animals being 0, 9,
and 3 out of 49, respectively (0%, 18%, 6%, respectively). In previous control groups of
females kept at the laboratory, the incidences of these tumours varied from 0 to 7%, with
a mean of 4%, which led the investigators to describe the benzotriazole findings as only
suggesting a possible carcinogenic effect (BIB95, NCI78).
     Death and decreased growth were noted when mice, already suffering from mamma-
ry tumours, were given eleven to fifteen injections (unspecified route) of 50-150 mg/kg
bw/day (BIB95). Sc administration of 100 mg/kg bw/day to rats, for 46 weeks, caused
liver damage (BIB95). No details were reported and therefore, this study is not suitable
for the evaluation of the health risk.
     When 315 male and female mice were administered oral doses of 100 mg/kg bw
weekly for 46 weeks (by stomach tube), an incidence of leukaemia of 13.7% was repor-
ted. This incidence was significantly higher than that of 3.4% which was observed in a
group of untreated mice. However, in a control group, where the solvent (type unspeci-
fied) used for the above dosing was administered alone, 11.1% developed leukaemia
(BIB95).
In a tumour promotion study, rats were fed benzotriazole at about 250 mg/kg bw/day for
eight weeks, along with a known liver carcinogen. Benzotriazole had no effect on the in-
cidence of liver tumours (BIB95).
Effects                                                                                    31
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<pre>      Conclusion
      From the carcinogenicity studies with rats and mice, the committee concludes that there
      is inconclusive evidence that benzotriazole is carcinogenic. Although higher incidences
      of — mostly benign — tumours in some organs were observed in treated than in concur-
      rent control animals, these tumours had mostly higher incidences in the low-dose than in
      the high-dose group, and occurred at fairly high rates in historical controls. The commit-
      tee could not assess a NOAEL since effects were observed in rats (neoplastic effects:
      brain tumours in males, thyroid tumours in females; nonneoplastic effects: decreased bo-
      dy weight gain, histological changes in liver cells, inflammation of prostate and uterus)
      and mice (neoplastic effects: lung tumours in females; nonneoplastic effects: decreased
      body weight gain, bone marrow myelofibrosis, haemorrhages in mesenteric lymph nodes)
      at the lowest doses tested. This study resulted in LOAELs of 295 and 1455 mg/kg
      bw/day in rats and mice, respectively.
6.2.5 Genotoxicity
      A summary of in vitro genotoxicity studies is presented in Table 1.
            Benzotriazole was found mutagenic in one S. typhimurium strain (strain TA 1535)
      in the presence of a metabolic activation system (Cib93b, Cib93c, Dun85, Zei87), while
      for this strain both positive (Cib93b, Cib93c) and negative (Dun85, Zei87) results were
      found in the absence of a metabolic activation system. In another study, a positive res-
      ponse was obtained in strain TA1535 in the presence of hamster liver S-9 preparations
      only (mouse and rat liver S9 gave negative results) (Dun80). When commercial benzotri-
      azole (purity: unknown) was tested, positive results were obtained in strains TA98,
      TA1537, and TA1538 as well (Cib93e, Cib93f). In E coli (strainWP2 uvrA), mutageni-
      city was observed both in the presence and in the absence of a metabolic activation sys-
      tem (Dun85).
      Effects                                                                                    32
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<pre>organism/ target cells                   endpoint                 concentration             metabolic response        ref.
                                                                                            activation
S. typhimurium
TA98, TA100, TA1537, TA1538              gene mutation            33-3333 µl/plate          -            negative     Dun80
                                                                                            +a           negative
TA1535                                                                                      -            negative
                                                                                            +b           positive
TA98, TA100, TA1537, TA1538              gene mutation            0.3-10,000 µl/plate       -            negative     Dun85
                                                                                            +a           negative
TA1535                                                                                      -            negative
                                                                                            +a           positive
TA97, TA98, TA100                        gene mutation            33-1666 µg/plate          -            negative     Zei87
                                                                                            +c           negative
TA1535                                                                                      -            negative
                                                                                            +c           positive
TA98, TA100, TA1537, TA1538              gene mutation            444-2250 µg/0.1 ml;       -            negative     Cib93b
                                                                  test repeated with        +b           negative
TA1535                                                            500-8000 µg/0.1 ml        -            positive
                                                                                            +b           positive
TA98, TA100, TA1537, TA1538              gene mutation            25-2025 µg/0.1 ml;        -            negative     Cib93c
                                                                  test repeated with        +c           negative
TA1535                                                            444-2250 µg/0.1 ml        -            positive
                                                                                            +c           positive
                                                                                e
TA100                                    gene mutation            25-2025 µg / 0.1 ml;      -            negative     Cib93e
                                                                  test repeated with        +c           negative
TA98, TA1537, TA1538d                                                           e
                                                                  50-4050 µg /0.1 ml        -            positive
                                                                                            +c           positive
                                                                                  e
TA100,                                   gene mutation            250-4000 µg /0.1 ml       -            negative     Cib93f
                                                                                            +b           negative
TA98, TA1535, TA1537, TA1538                                                                -            positive
                                                                                            +b           positive
E. Coli                                  Gene mutation            0.3-10,000 µg/plate       -            positive     Dun85
WP2 uvra                                                                                    +a           positive
E. Coli                                  SOS induction (DNA da- up to 100 mM or up to solu- -            negative
PQ37                                     mage)                    bility limitf             +            negative
Chinese hamster ovary cells              HGPRT forward            50-1000 mg/ml             -            negative
                                         mutation                                           +c           negative
nr = not reported.
a
     From rat, mouse, and hamster liver (non-induced and Arochlor-induced).
b
     From hamster liver (Arochlor-induced).
c
     From rat liver (Arochlor-induced).
d
     TA1538 used in repeated test only.
e
     Commercial benzotriazole tested (purity: unknown).
f
     A great number of compounds were tested at 3-5 different concentrations at half-log intervals at a maximum level of 100 mM
     or the limit of solubility. Specific concentrations per compounds were not given.
              Effects                                                                                                         33
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<pre>As to in vitro mammalian cell systems, benzotriazole (“Benzotriazol Granulat”/”Preven-
tol CI-8“; purity: 99.83%; vehicle: DMSO) was tested in the HGPRT forward mutation
assay in CHO cells. Without adding a metabolic activating system, negative results were
obtained in two independent trials at dose ranges of 400-1000 µg/ml (5 duplicate do-
ses/trial). In the presence of an induced rat-liver-derived S9 mix, a slight statistically sig-
nificant increase in mutation frequency was observed at one of the mid-dose levels in one
of the trials (dose range: 200-1000 µg/ml; 5 duplicate doses/trial). However, this incre-
ase was within historical control levels, not dose related, and not found in the other trial
(Boe87). In view of the survival rates (ca. 72% at 1000 µg/ml) in the nonactivating test,
higher levels could have been tested. However, from the results presented for the dose
range tested, the committee concludes that a positive result is unlikely to occur at higher
doses than tested. The committee concludes (in accordance with Boe87) that benzotria-
zole is negative in this assay.
     In validating an in vitro transformation assay which was developed to detect muta-
gens/carcinogens by measuring the acquisition of attachment independence (recognized
as being characteristic of transformed cells), benzotriazole was positive (Tra81).
     In vivo, benzotriazole was investigated for its potential to induce clastogenic effects
with the mouse bone marrow micronucleus test. In this unpublished study, performed ac-
cording to relevant OECD guidelines, there was no increase in the incidence of micronu-
clei in polychromatic erythrocytes obtained from mice (Bor:NMRI; n=5/sex/sacrifice)
24, 48, and 72 hours after administration of a single oral dose (gavage; vehicle: PEG
400) of 800 mg/kg bw of benzotriazole (granules; “Preventol CI8-100”; purity:
99.83%). Treatment did not affect the polychromatic/normochromatic erythrocyte ratio.
The level, selected from a preceding range-finding test, was clearly toxic as was shown
by compound-related symptoms such as apathy, reduced motility, abdominal position,
cramp, convulsion, and rapid and feeble breathing and mortality (in 1/40) (see also
§6.2.2) (Her88).
Conclusion
In vitro, benzotriazole was mutagenic in bacterial cell systems (S. typhimurium, E coli),
but not in mammalian cells (Chinese hamster ovary cells). An indication test for DNA
damage (SOS chromotest in E. coli) was negative as well. In Vivo, benzotriazole did not
induce micronuclei in the bone marrow of orally treated mice. Benzotriazole induced cell
transformation.
Effects                                                                                         34
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<pre>6.2.6 Reproduction toxicity
      In the DFG documentation, two Russian studies are mentioned in which the effects of
      premating exposure of female rats on developmental parameters were examined. Expo-
      sure might have induced changes in hormonal balance (increased cycles). Data on deve-
      lopmental parameters (fetal and pup mortality, anomalies) were inconsistent and could
      not be properly evaluated because they were inadequate as well (Gre99).
      Conclusion
      The committee did not find valid data on the reproduction toxicity of benzotriazole.
6.3   Summary
      Contact dermatitis in metalworkers was observed after skin exposure to benzotriazole.
           In experimental animals, pure benzotriazole was a severe eye irritant and at most a
      slight skin irritant; benzotriazole is not a skin sensitizer. Based on acute lethal toxicity
      data and using EC-classification criteria, benzotriazole should be classified as harmful
      following inhalation and oral exposure.
           No valid repeated-dose short-term toxicity studies were available. From long-term
      carcinogenicity studies, there is inconclusive evidence that benzotriazole is carcinogenic
      in rats and mice, since these tumours had mostly higher incidences in the low-dose than
      in the high-dose group, and occurred in fairly high rates in historical controls. A
      NOAEL could not be established since effects were observed in rats (neoplastic effects:
      brain tumours in males, thyroid tumours in females; nonneoplastic effects: decreased bo-
      dy weight gain, histological changes in the liver, inflammation of prostate and uterus)
      and mice (neoplastic effects: lung tumours in females; nonneoplastic effects: decreased
      body weight gain, bone marrow myelofibrosis, haemorrhages in mesenteric lymph nodes)
      at the lowest dose tested. The LOAELs were set at 295 and 1455 mg/kg bw/d in ratsand
      mice, respectively.
           In vitro, benzotriazole is mutagenic in S. typhimurium TA 1535 and in E. coli, but
      not in chinese hamster ovary cells. The SOS chromotest in E. coli, an indicator test for
      DNA damage was negative. In vivo, benzotriazole was negative in an oral mouse bone
      marrow micronucleus assay.
           There were no valid data on the reproduction toxicity.
      Effects                                                                                      35
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<pre>Chapter 7
        Existing guidelines, standards and
        evaluations
7.1     General population
        No guidelines for the general population were found.
7.2     Working population
        No occupational exposure limits/standards for benzotriazole were established or recom-
        mended in the Netherlands, the Nordic countries, the UK, and by the ACGIH (USA). In
        Germany, benzotriazole was listed among those compounds for which no limit could be
        established (DFG99).
            In 1988, DFG concluded that occupational exposure to benzotriazole could be irrita-
        ting to the eyes, but not to the skin. Sensitization may occur. Cytostatic effects were in-
        duced at such high dose levels that these effects are concluded not to occur at workplace
        exposure conditions. Since (reversible) CNS effects following single oral or inhalation
        exposure were induced at relatively high levels and since the dose-response curve might
        be steep, acute toxic effects are not expected from using/handling benzotriazole-contai-
        ning products (namely, coolant lubricants which contain 0.05% benzotriazole). Toxic ef-
        fects following long-term exposure could not be evaluated conclusively, since there were
        no data available from (semi)chronic inhalation studies or from reproduction toxicity
        studies. On the other hand, significant toxic effects (decreased body weight gain) were
        induced at only relatively high dietary levels. Carcinogenic effects might occur at high
        Existing guidelines, standards and evaluations                                              36
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<pre>doses, although animal experiments were inconclusive. Benzotriazole would be a weak
carcinogen only (Gre99).
Existing guidelines, standards and evaluations                                      37
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<pre>Chapter 8
        Hazard assessment
8.1     Assessment of health hazard
        Based on experimental animal data with benzotriazole of unknown purity and limited hu-
        man data, the committee concludes that benzotriazole is slightly irritating to the eyes
        and, at most, slightly irritating to the skin. In addition, benzotriazole is not a skin sensiti-
        zer.
             Based on acute letal toxicity data and using EC-classification criteria, benzotriazole
        should be classified as harmful following inhalation and oral exposure.
             The committee did not find data from valid repeated-dose short-term toxicity or de-
        velopmental toxicity studies.
             Benzotriazole was mutagenic in in vitro bacterial cells, but not in mammalian cell
        systems. The bacterial test indicator for DNA damage was negative. In vivo, benzotria-
        zole did not induce micronuclei in the bone marrow of orally treated mice.
             In oral carcinogenicity studies in rats and mice, higher incidences of — mostly be-
        nign — tumours in some organs were observed in treated than in concurrent control ani-
        mals. These tumours had mostly higher incidences in low-dose than in high-dose groups,
        and occurred at fairly high rates in historical controls. The committee considers the re-
        sults of these studies to be inconclusive with respect to carcinogenic potential of ben-
        zotriazole. The committee could not assess a NOAEL in these studies since several
        effects were observed in rats (neoplastic effects: brain tumours in males, thyroid tumours
        in females; nonneoplastic effects: decreased body weight gain, histological changes in the
        liver, inflammation of prostate and uterus) and mice (neoplastic effects: lung tumours in
        Hazard assessment                                                                                38
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<pre>  females; nonneoplastic effects: decreased body weight gain, bone marrow myelofibrosis,
  haemorrhages in mesenteric lymph nodes) at the lowest dose tested. The LOAELs were
  set at 295 and 1455 mg/kg bw/day in rats and mice, respectively.
       In view of the (inconclusive) evidence on the carcinogenic potential of benzotriazole
  in rodents and the mutagenic effects of benzotriazole in bacterial systems along with the
  absence of mutagenic and genotoxic effects in mammalian cells and in mouse bone
  marrow in vivo, the committee considers the data base inconclusive regarding carcinoge-
  nicity of this chemical. Clearly, the data base is inadequate to classify benzotriazole as
  ‘known to be carcinogenic to humans’ or as ‘should be regarded as carcinogenic to hu-
  mans’, but it may raise concern for humans. Therefore, the committee classifies
  1,2,3-benzotriazole as a suspected human carcinogen (comparable with EU class 3B).
  Assuming — for the time being — that benzotriazole does not possess carcinogenic pro-
  perties, one might use the available oral data to derive an occupational exposure limit.
  The LOAEL of 295 mg/kg bw/d from the chronic rat study could be used as a starting
  point. It will be clear that extrapolation from this LOAEL will lead to a limit value*
  much higher than the maximum accepted concentrations set in the Netherlands for respi-
  rable and inhalable nuisance dust, viz, 5 and 10 mg/m3, respectively. Since benzotriazole
  at room temperature will be present at the workplace as a dust, these values could then
  be applied as occupational exposure limits for benzotriazole.
       Since, however, it cannot be excluded that benzotriazole is a genotoxic carcinogen, it
  was deemed desirable to calculate the cancer risk associated with an occupational expo-
  sure level of 10 mg/m3. Using a “worst-case” approach (see Annex), occupational expo-
  sure to 10 mg/m3 for 40 years should be associated with an excess cancer mortality risk
  of 5 per 10.000.
       Furthermore, benzotriazole appeared to be a slight eye irritant in experimental ani-
  mals. This may indicate that eye and/or respiratory tract irritation can not be excluded to
  occur in workers exposed to benzotriazole concentrations of 5 mg/m3 for respirable par-
  ticles and to 10 mg/m3 for inhalable ones. Since no eye irritation studies in humans were
  available, and repeated-dose inhalation toxicity studies in experimental animals were ab-
  sent, the committee concludes that it is not justifiable to derive a health-based occupatio-
  nal exposure limit from the available data.
* The following considerations should be taken into account: intra- and interspecies variation, differences between expe-
  rimental conditions and the exposure pattern of the worker, type of critical effect, dose-response-curve, the absence of
  a NOAEL, the confidence of the data base. The resulting oral dose is converted to an inhalation concentration (HBR-
  OEL) assuming a respiratory volume of 10 m3 for an eight-hour working day and a worker body weight of 70 kg.
  Hazard assessment                                                                                                     39
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<pre>8.2 Groups at extra risk
    No specific groups at extra risk are identified in the literature.
8.3 Health-based recommended occupational exposure limit
    The Dutch Expert Committee for Occupational Standards considers the data base on
    benzotriazole too poor to justify recommendation of a health-based occupational exposu-
    re limit.
         The committee classifies 1,2,3-benzotriazole as a suspected human carcinogen
    (comparable with EU class 3(B)).
    Hazard assessment                                                                       40
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<pre>Chapter 9
        Recommendations for research
             Genotoxicity: a gene mutation test and a chromosome aberration assay using euka-
             ryotic cells and depending on the results an appropriate in vivo test.
             Reproduction toxicity studies.
             Subchronic and chronic inhalation toxicity studies in rats.
             A human volunteer respiratory and dermal irritation test.
        The Hague, 22 November 2000,
        for the committee
        dr ASAM van der Burght,                   Prof. dr GJ Mulder,
        scientific secretary                      chairman
        Recommendations for research                                                          41
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<pre>       References
Alb48  Albert A, Goldacre R, Phillips J. The strenght of heterocyclic bases. J Chem Soc 1948; 2240-9.
BIB95  BIBRA Toxicology International. Toxicity profile of benzotriazole. Carshalton (Surrey), UK: BIBRA
       Toxicology International, 1995.
Boe8   Den Boer WC. Mutagenicity test on Benzotriazol Granulat in the CHO HGPRT forward mutation assay.
       Veenendaal, the Netherlands: Hazleton Biotechnologies Veenendaal Laboratory, 1987; HBC study no
       E-95553-0-435 (study submitted to Bayer AG, Institut für Toxikologie, Wuppertal, Germany)
       (unpublished data submitted to THE COMMITTEE by Bayer AG).
Boe89  Boer de EM, van Ketel WG, Bruynzeel DP. Dermatoses in metal workers. 2. Allergic contact dermatitis.
       Contact Dermatitis 1989; 20: 280-6.
Che99  Chemiekaarten: gegevens voor het veilig werken met chemicaliën/ [ed by]
       samenwerkingsverband-chemiekaarten (TNO Arbeid, VNCI) 15 th ed. The Hague, The Netherlands. Ten
       HAgen & Stam, 1999:133.
Cib93a Ciba-Geigy Corp. Report on skin irritation in the rabbit after single application of TK11’237 with cover
       letter dated 072893. Springfield VA, USA: National Technical Information Service (NTIS), 1993; order
       no NTIS/OTS0538206.
Cib93b Ciba-Geigy Corp. Salmonella/mammalian-microsome mutagenicity test with TK 11’237 with cover letter
       dated 072893. Springfield VA, USA: National Technical Information Service (NTIS), 1993; order no
       NTIS/OTS0538209.
Cib93c Ciba-Geigy Corp. Salmonella/mammalian-microsome mutagenicity test with TK 11’237 with cover letter
       dated 072893. Springfield VA, USA: National Technical Information Service (NTIS), 1993; order no
       NTIS/OTS0538210.
       References                                                                                               42
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<pre>Cib93d Ciba-Geigy Corp. Report on skin irritation in the rabbit after single application of TK10’637 with cover
       letter dated 072893. Springfield VA, USA: National Technical Information Service (NTIS), 1993; order
       no NTIS/OTS0538211.
Cib93e Ciba-Geigy Corp. Salmonella/mammalian-microsome mutagenicity test with TK 10’637 with cover letter
       dated 072893. Springfield VA, USA: National Technical Information Service (NTIS), 1993; order no
       NTIS/OTS0538213.
Cib93f Ciba-Geigy Corp. Salmonella/mammalian-microsome mutagenicity test with TK 10’637 with cover letter
       dated 072893. Springfield VA, USA: National Technical Information Service (NTIS), 1993; order no
       NTIS/OTS0538214.
Dav77  Davis LN, Santodonato J, Howard PH, et al. Investigation of selected potential environmental
       contaminants: benzotriazoles. Springfield VA, USA: National Technical Information Service (NTIS),
       1977; rep no PB266366.
DFG99  Deutsche Forschungsgemeinschaft (DFG): Senatskommission zur Prüfung gesundheitsschädlicher
       Arbeitsstoffe. MAK- und BAT-Werte-Liste 1999. Maximale Arbeitsplatzkonzentrationen und biologische
       Arbeitsstofftoleranzwerte. Weinheim, FRG: Wiley-VCH Verlag GmbH, 1999: 28 (Mitteilung 35).
Duc80  Ducombs G, Tamisier JM, Texier L. Contact dermatitis to 1-H benzotriazole. Contact Dermatitis 1980; 6:
       224-5.
Dun80  Dunkel VC, Simmon VF. Mutagenic acitivity of chemicals previously tested for carcinogenicity in the
       national cancer institute bioassay program. IARC Sci Publ 1980; 27: 283-302.
Dun85  Dunkel VC, Zeiger E, Brusick, et al. Reproducibility of microbial mutagenicity assays. 2. Testing of
       carcinogens and noncarcinogens in Salmonella typhimurium and E. coli. Environ Mutagen 1985; 7 (suppl
       5): 1-248.
Gal85  Galloway SM, Bloom AD, Resnick M, et al. Development of a standard protocol for in vitro cytogenetic
       testing with chinese hamster ovary cells: Comparison of results for 22 compounds in two laboratories.
       Environ Mutagen 1985; 7: 1-51.
Gol91  Gold SL, Slone TH, Manley NB, et al. Target organs in chronic bioassays of 533 chemical carcinogens.
       Environ Health Perspect 1991; 93: 233-46.
Gre99  Greim H, ed. Benzotriazol. In: Gesundheidsschädliche Arbeitsstoffe. Toxikologisch-arbeitsmedizinische
       Begründungen von MAK-Werte (Maximale Arbeitsplatz-Konzentrationen). 1st-29th ed. Weinheim, FRG:
       Wiley-VCH Verlag GmbH, 1999.
Han95  Hansch C, Leo A, Hoekman D. Exploring QSARs. Hydrophobic, electronic and steric constants;
       Washington DC, USA: Amer Chem Soc, 1995; 18.
Haw81  Hawn GG, Diehl PA, Talley CP. High-performance liquid-chromatographic determination of aromatic
       triazole corrosion inhibitors in aqueous solutions. J Chromatogr Sci 1981; 19: 567-9.
Hea95  Health Council of the Netherlands: Dutch Expert Committee on Occupational Standards (DECOS).
       Calculating cancer risk. Rijswijk, the Netherlands: Health Council of the Netherlands, 1995; pub no
       1995/06WGD.
       References                                                                                               43
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<pre>Hei88  Heimann KG. Benzotriazol Granulat (Preventol CI-8). Untersuchungen auf hautsensibilisierende
       Wirkung bei Meerschweinchen (Maximierungstest). Wuppertal, Germany: Bayer AG, Fachbereich
       Toxikologie, 1988; rep no 16482 (unpublished data submitted to THE COMMITTEE by Bayer AG).
Her88  Herbold BA. Preventol CI8-100. Micronucleus test on the mouse to evaluate for clastogenic effects.
       Wuppertal, Germany: Bayer AG, Fachbereich Toxikologie, 1988; rep no 16737 (unpublished data
       submitted to THE COMMITTEE by Bayer AG).
Hof82  Hoffman H, Pooth R. Biotransformation von 1H-Benzotriazol und N-1-Alkylbenzotriazolen in vitro. Arch
       Pharm 1982; 315: 422-8.
Hud88  von der Hude W, Behm C, Gürtler R, et al. Evaluation of the SOS chromotest. Mutat Res 1988; 203:
       81-94.
Huf91  Huff J, Cirvello, Haseman J, et al. Chemicals associated with site-specific neoplasia in 1394 long-term
       carcinogenesis experiments in laboratory rodents. Environ Health Perspect 1991; 93: 247-70.
Mau84  Maurer T, Meier F. Sensitization potential of benzotriazole. Contact Dermatitis 1984; 10 : 163-5.
NCI78  National Cancer Institute (NCI). Bioassay of 1H-Benzotriazole for possible carcinogenicity; CAS No.
       95-14-7. SpringfieldVA, USA: National Technical Information Service (NTIS), 1978; order no PB285202
       (NTP Techn Rep Ser No. 88).
NIO00  US National Institute of Occupational Health (NIOSH). 1H-Benzotriazole In: Registry of Toxic Effects of
       Chemical Substances (RTECS)[CD-ROM], issue April 2000. SilverPlatter International, 1998 (last
       update benzotriazole file: April 1999).
NLM00  US National Library of Medicine (NLM). 1,2,3-Benzotriazole in: Hazardous Substances Databank
       (HSDB) [CD-ROM], issue March 2000. SilverPlatter International, 2000 (last update benzotriazole file:
       Februari 2000).
Ros90  Rosenkranz HS, Ennever FK, Klopman G. Relationship between carcinogenicity in rodents and the
       induction of sister chromatid exchanges and chromosomal aberrrations in Chinese hamster ovary cells.
       Mutagenesis 1990; 5: 559-71.
Ruf87  Ruf J. Untersuchungen zum Reiz-/Ätzpotential an Haut und Auge (Kaninchen) nach OECD-Richtlinie
       No. 404 und 405. Wuppertal, Germany: Bayer AG, Fachbereich Toxikologie, 1987; rep no 15529
       (unpublished data submitted to THE COMMITTEE by Bayer AG).
Tra81  Traul KA, Takayama K, Kachevsky V, et al. A rapid in vitro assay for carcinogenicity of chemical
       substances in mammalian cells utilizing an attachment-independence endpoint. 2 - Assay validation. J
       Appl Toxicol 1981; 1: 190-5.
Zei87a Zeiger E. Carcinogenicity of mutagens: predictive capability of the Salmonella mutagenesis assay for
       rodent carcinogenicity. Cancer Res 1987; 47: 1287-96.
Zei87b Zeiger E, Anderson B, Haworth S, et al. Salmonella mutagenicity tests. 3. Results from the testing of 255
       chemicals. Environ. Mutagen 1987; 9 (suppl. 9): 1-110.
       References                                                                                                44
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<pre>A Request for advice
B The committee
C Comments on the public draft
D Calculation of the cancer risk of benzotriazole
E Abbreviations
  Annexes
                                                  45
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<pre>Chapter A
        Request for advice
        In a letter dated October 11, 1993, ref DGA/G/TOS/93/07732A, to, the State Secretary
        of Welfare, Health and Cultural Affairs, the Minister of Social Affairs and Employment
        wrote:
        Some time ago a policy proposal has been formulated, as part of the simplification of the governmental
        advisory structure, to improve the integration of the development of recommendations for health based
        occupation standards and the development of comparable standards for the general population. A conse-
        quence of this policy proposal is the initiative to transfer the activities of the Dutch Expert Committee on
        Occupational Standards (DECOS) to the Health Council. DECOS has been established by ministerial de-
        cree of 2 June 1976. Its primary task is to recommend health based occupational exposure limits as the
        first step in the process of establishing Maximal Accepted Concentrations (MAC-values) for substances
        at the work place.
        In an addendum, the Minister detailed his request to the Health Council as follows:
        The Health Council should advice the Minister of Social Affairs and Employment on the hygienic aspects
        of his policy to protect workers against exposure to chemicals. Primarily, the Council should report on
        health based recommended exposure limits as a basis for (regulatory) exposure limits for air quality at
        the work place. This implies:
              A scientific evaluation of all relevant data on the health effects of exposure to substances using a
              criteria-document that will be made available to the Health Council as part of a specific request for
              advice. If possible this evaluation should lead to a health based recommended exposure limit, or, in
        Request for advice                                                                                           46
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<pre>    the case of genotoxic carcinogens, a ‘exposure versus tumour incidence range’ and a calculated con-
    centration in air corresponding with reference tumour incidences of 10-4 and 10-6 per year.
    The evaluation of documents review the basis of occupational exposure limits that have been recent-
    ly established in other countries.
    Recommending classifications for substances as part of the occupational hygiene policy of the
    government. In any case this regards the list of carcinogenic substances, for which the classification
    criteria of the Directive of the European Communities of 27 June 1967 (67/548/EEG) are used.
    Reporting on other subjects that will be specified at a later date.
In his letter of 14 December 1993, ref U 6102/WP/MK/459, to the Minister of Social
Affairs and Employment the President of the Health Council agreed to establish DECOS
as a Committee of the Health Council. The membership of the Committee is given in an-
nex B.
Request for advice                                                                                         47
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<pre>Chapter B
        The committee
           GJ Mulder, chairman
           professor of toxicology; Leiden University, Leiden
           RB Beems
           toxicologic pathologist; National Institute of Public Health and the Environment,
           Bilthoven
           PJ Borm
           toxicologist; Heinrich Heine Universität Düsseldorf (Germany)
           JJAM Brokamp, advisor
           Social and Economic Council, The Hague
           VJ Feron,
           professor of toxicology; TNO Nutrition and Food Research Institute, Zeist
           DJJ Heederik
           epidemiologist; Agricultural University, Wageningen
           LCMP Hontelez, advisor
           Ministry of Social Affairs and Employment, The Hague
           G de Jong
           occupational physician; Shell International Petroleum Maatschappij, The Hague
           J Molier-Bloot
           occupational physician; BMD Akers bv, Amsterdam
           IM Rietjens
           professor in biochemical toxicology; Wageningen University, Wageningen
        The committee                                                                        48
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<pre>    H Roelfzema, advisor
    Ministry of Health, Welfare and Sport, Den Haag
    T Smid
    occupational hygienist; KLM Health Safety & Environment, Schiphol and professor
    of working conditions, Free University, Amsterdam
    GMH Swaen
    epidemiologist; Maastricht University, Maastricht
    HG Verschuuren
    toxicologist; DOW Europe, Horgen (Switzerland)
    F de Wit
    occupational physician; Labour Inspectorate, Arnhem
    CA Bouwman, scientific secretary
    Health Council of the Netherlands, Den Haag
    ASAM van der Burght, scientific secretary
    Health Council of the Netherlands, Den Haag
The first draft of the present advisory report was prepared by H Stouten, MSc, from the
Department of Occupational Toxicology of the TNO Nutrition and Food Research, by
contract with the Ministry of Social Affairs and Employment.
Secretarial assistance: J Toet.
Lay-out: J van Kan.
The committee                                                                           49
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<pre>Chapter C
        Comments on the public draft
        A draft of this report was released in 1999 for public review. The following persons or
        organisation commented on the draft document:
            A Aalto
            Occupational Safety and Health division, Tampere, Finland
            HJ Weideli
            CIBA Specialty Chemicals, Basel, Switzerland
            E Bomhard and G Stropp
            Bayer AG, Wuppertal, Germany
        <B3>                                                                                    50
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<pre>Chapter D
        Calculation of the cancer risk of
        benzotriazole
        In the female rats of the low dose group, a statistical significant increase in the incidence
        of thyroid tumours (C-cell adenomas and carcinomas in 5/43; p=0.028) was found
        (NCI78).
              The incidence of tumour bearing animals per mg/kg bw/day (lifespan conditions, as-
        suming a linear dose-response relationship), Idose, is calculated as follows:
                                                            I e - Ic
        I*dose =   C x (X po /L) x (X pe /L) x exposure hours per day/24 x exposure days per week/7
                                                  15/43 - 0/43
        =           (295 mg/kg/d) x (78×7 d /1000 d ) x (105×7 d /1000 d ) x 24/24 x 7/7
        = 9.8 x 10-4 [mg/kg/d]-1
        Assuming the average worker lives 75 years, is exposed 8 h/d, 5 d/w, 48 w/y, for 40 ye-
        ars, and inhales 10 m3 per 8-hour working day and using the estimated incidence of 9.8 x
*       Idose= the carcinogenic activity attributable to the exposure to the substance per unit daily dose under lifespan condi-
        tions, assuming a linear dose response relationship, usually expressed per mg/m3 or per mg/kg bw/day.
        Ie and Ic = incidence of tumour bearing animals or tumours in exposed and control animals, respectively,
        Xpo = exposure period, Xpe = experimental period
        L = standard lifespan for the animals in question (L rat is assumed to be 1000 days)
        Calculation of the cancer risk of benzotriazole                                                                          51
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<pre>10-4 as a starting point, the additional lifetime cancer risk per mg/m3 under occupational
conditions (HBC-OCRV) amounts to:
9.8 x 10-4 x 40/75 x 5/7 x 48/52 x 10/70 = 5 x 10-5
From this, the additional lifetime cancer risk for 40 years of occupational exposure to 10
mg/m3 amounts to 10 x (5 x 10-5) = 5 x 10-4
Calculation of the cancer risk of benzotriazole                                            52
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<pre>Chapter E
        Abbreviations
        bp         boiling point
        EC50       concentration at which a described effect is found in 50% of the exposed animals or at
                   which the effect is decreased up to 50% of the control value
        HBR-OEL    health based recommended occupational exposure limit
        h          hour
        IC50       concentration at wAbbreviationshich inhibition of a certain function is found up to 50% of
                   the control value
        LC50       lethal concentration for 50% of the exposed animals
        LClo       lowest lethal concentration
        LD50       lethal dose for 50% of the exposed animals
        LDlo       lowest lethal dose
        LOAEL      lowest observed adverse effect level
        MAC        maximaal aanvaarde concentratie (maximal accepted concentration)
        MAEL       minimal adverse effect level
        MAK        Maximale Arbeitsplatz Konzentration
        MOAEL      minimal observed adverse effect level
        MTD        maximum tolerated dose
        NAEL       no adverse effect level
        NEL        no effect level
        NOAEL      no observed adverse effect level
        OEL        occupational exposure limit
        PEL        permissible exposure limit
        ppb        parts per billion (v/v)10-9
        ppm        parts per million (v/v)10-6
        RD50       concentration at which a 50% decrease of respiratory rate is observed
        REL        recommended exposure limit
        STEL       short term exposure limit
        Abbreviations                                                                                         53
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<pre>tgg         tijd gewogen gemiddelde
TLV         threshold limit value
TWA         time weighted average
Vmax        maximal reaction velocity of an enzyme
Organisations
ACGIH       American Conference of Governmental Industrial Hygienists
CEC         Commission of the European Communities
DECOS       Dutch Expert Committee on Occupational Standards
DFG         Deutsche Forschungsgemeinschaft
EPA         Environmental Protection Agency (USA)
FDA         Food and Drug Administration (USA)
HSE         Health and Safety Executive (UK)
IARC        International Agency for Research on Cancer (WHO)
INRS        Institut National de Recherche et de Sécurité (France)
NIOSH       National Institute for Occupational Safety and Health (USA)
NTP         National Toxicology Programme (USA)
OECD        Organisation for Economic Cooperation and Development
OSHA        Occupational Safety and Health Association (USA)
RTECS       Registry of Toxic Effects of Chemical Substances
SER         Social and Economic Council (Sociaal-Economische Raad NL)
WATCH       Working Group on the Assessment of Toxic Chemicals (UK)
WHO         World Health Organisation
Toxicological terms
bid         bis in diem (twice per day)
bw          body weight
CARA        chronic non-specific respiratory diseases
CHD         coronary heart disease
CNS         central nervous system
ECG         electrocardiogram
EEG         electro encephalogram
FCA         Freunds Complete Adjuvans
FEV         forced expiratory volume
FSH         follicle stimulating hormone
GD          gestation day(s)
GPMT        guinea pig maximisation test
GSH         glutathione
HLiA        hamster liver activated
IHD         ischaemic heart disease
im          intramuscular
ip          intraperitoneal
ipl         intrapleural
it          intratracheal
iv          intravenous
LH          lutheinising hormone
MAC         minimal alveolar concentration
MFO         mixed function oxidase
Abbreviations                                                           54
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<pre>NA             not activated
PNS            peripheral nervous system
po             per os (= oral)
RBC            red blood cells
RLiA           rat liver activated
SCE            sister chromatid exchange
sc             subcutaneous
UDS            unscheduled DNA-synthesis
Statistical terms
GM             geometric mean
OR             Odds Ratio
RR             relative risk
SD             standard deviation
SEM            standard error of mean
SMR            standard mortality ratio
Analytical methods
AAS            atomic absorption spectroscopy
BEEL           biological equivalent exposure limit
BEI            biological exposure index
BEM            biological effect monitoring
BM             biological monitoring
ECD            electron capture detector
EM             environmental monitoring
FID            flame ionisation detector
GC             gas chromatography
GLC            gas liquid chromatography
GSC            gas solid chromatography
HPLC           high performance liquid chromatography
IR             infrared
MS             mass spectrometry
NMR            nuclear magnetic resonance
PAS            personal air sampling
TLC            thin layer chromatography
UV             ultraviolet
Abbreviations                                         55
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