Jan 14, 2005 - Schulz, Ines Seibt, Maria Tello Rodriguez, Christl Treumer, ...... FARMAKOWSKIJ presented a historical manual, which has been translated by ...... C.L. Rose and D.W. Von Endt, Protein ...... The ashes of the leather amounted to 0.16 %. ...... SIROIS 2001: P. Jane Sirois, The Analysis of Museum Objects for ...
Investigations on Super Fluid Extraction (SFE) with Carbon Dioxide on Ethnological Materials and Objects Contaminated with Pesticides
Diplomarbeit
vorgelegt am Fachbereich 5, Gestaltung Studiengang Restaurierung / Grabungstechnik der Fachhochschule für Technik und Wirtschaft Berlin
2
Helene Tello Date: Berlin, September 30, 2006
3
1st Advisor: Prof. Dr. Matthias Knaut 2nd Advisor: Dr. Achim Unger
4
Zusammenfassung: Das Ziel der Diplomarbeit ist es, die Extraktion von Pestiziden und Schwermetallverbindungen aus ethnologischem Kulturgut mit superkritischem Kohlendioxid aus restauratorischer Sicht zu untersuchen und zu beurteilen. Dabei wird zunächst der nationale und internationale Einsatz von Pestiziden an Sammlungsgegenständen, die damit verbundenen Schäden an den Objekten und die gesundheitliche Gefährdung von Mitarbeitern entsprechender Sammlungen beschrieben. Die Bedeutung des Einsatzes von Pestiziden an Objekten und Materialien im Ethnologischen Museum in Berlin und die gesundheitliche Belastung der dortigen Mitarbeiter wird in einem weiteren Schritt dargestellt. Anschließend werden die derzeitigen Verfahren zur Reinigung und Dekontamination von Pestizid belastetem Sammlungsgut diskutiert und der aktuelle Stand der Dekontamination von Kunst- und Kulturgut erläutert. Die Möglichkeiten der massenweisen Dekontamination mit superkritischem Kohlendioxid für unterschiedliche ethnologische Materialien und Objekte werden abschließend in einem Überblick zusammengefasst und diskutiert. Schlagworte: Ethnologisches Kulturgut, Dekontamination, Hochdruckextraktion, superkritisches Kohlendioxid, Pestizide, Schwermetalle Summary: The aim of this thesis is to examine and to assess the extraction of pesticides and heavy metal compounds from ethnological objects by using supercritical carbon dioxide from the viewpoint of conservation. First, the use of pesticides in collections with cultural heritage and the risk to health for persons expanded to a national and international level are described here. Secondly, the significance of the use of pesticides on collections in the Ethnological Museum in Berlin and the health hazard for the staff and other persons is described. The current procedures of the cleaning and the decontamination of collections contaminated with pesticides are discussed and the present state of decontamination of cultural heritage is interpreted. Finally the possibilities of the decontamination with supercritical carbon dioxide of ethnological materials and objects in masses are summarized and discussed. Keywords: ethnological heritage, decontamination, super fluid extraction, supercritical carbon dioxide, pesticides, heavy metal compounds
5
Acknowledgements I should like to extend my thanks (in alphabetical order) to Conny Ammermann, Claudia Augustat, Karin Bader, Sabine Becker, Ingrid Behning, Jutta Billig, Christine Binroth, Adele Boiger, Peter Bolz, Carole Dignard, Gabriele Drescher, Nils Engel, Madeleine Fang, Barbara Fölber, Martin Franken, Matthias Gerschwitz, Frank Gockel, Mario Graber, Richard Haas, Greta Hansen, Monika Harter, Thilo Heinken, Vera Heyden, Barbara Hille, Erich Jelen, Marianne Klaus, Carola Klinzmann, Matthias Knaut, Michael Kraus, Petra Kress, Sonja Krug, Ludolf Kuchenbuch, Thomas Kupferstein, Andrea Lang, Jirina Lehmann, Ruth Norton, Else Paetzold, Regine-Ricarda Pausewein, Boaz Paz, Hans-Joachim Radosuboff, Maria-Sofie Rohner, Cornelia Rosenow, Renate Sander, Emily Schalk, Klaus Scharn, Thomas Schelske, Alexandra Schieweck, Markus Schindlbeck, Anne Lisbeth Schmidt, Haiko Schulz, Ines Seibt, Maria Tello Rodriguez, Christl Treumer, Bernhard Trommer, Arnulf von Ulmann, Achim Unger, Evelyn Weilert, Sibylle Weisensee-Meencke, Felicitas Weisse, Robert White, Birgit Wichmann, Dagmar Winterlich, Jutta Zeller, Anja Zenner and Hong Zhou.
My gratitude for their support of my thesis also goes to the following institutions: Analyse Labor Berlin, Ethnologisches Museum Berlin, Field Museum Chicago, Forschungsinstitut für Leder und Kunststoffbahnen gGmbH Freiberg, FraunhoferInstitut für Umwelt, Sicherheits- und Energietechnik UMSICHT Oberhausen, Institut für Restaurierungs- und Konservierungswissenschaft an der Fachhochschule Köln, Natural Museum of Natural History of the Smithsonian Institution Washington D.C., Naturkundemuseum der Humboldt Universität Berlin, Messer Group GmbH Application Technology Krefeld and the Rathgen-Forschungslabor der Staatlichen Museen Berlin. Dedicated to Klaus Scharn, chief conservator at the Ethnological Museum in Berlin from 1985-1999
6
Table of Contents Acknowledgements........................................................................................................... 6 1
Introduction ........................................................................................................... 12
2
Approach............................................................................................................... 13
3
History of pest control of ethnological objects ....................................................... 14 3.1 Sources of pest control ................................................................................. 14 3.2 Pest control in German collections ............................................................... 16 3.3 Pest control in European collections............................................................. 21 3.4 Pest control in U.S. American and Canadian collections .............................. 25 3.5 Discussion and assessment ......................................................................... 29
4
Damage to collections with pesticides................................................................... 31 4.1 Damage to German collections..................................................................... 31 4.2 Damage to European collections .................................................................. 32 4.3 Damage to U.S. American and Canadian collections ................................... 33 4.4 Discussion and assessment ......................................................................... 34
5
Chronology of the use of pesticides on collection items at the Ethnological Museum in Berlin .............................................................................. 34 5.1 Preparations and procedures employed ....................................................... 34 5.1.1
Preparations employed during collection trips in 19th century................. 35
5.1.2
Preparations from late 19th century until World War II ............................ 35
5.1.3
Preparations employed during World War II........................................... 42
7
5.1.4
Preparations employed after World War II until the late 20th century ...... 44
5.1.5
Current use of preparations and procedures .......................................... 48
5.2 Discussion and assessment ......................................................................... 50 6
Current state of contamination with pesticides in the collections of the Ethnological Museum in Berlin .............................................................................. 51 6.1 The pesticides determined and their toxicological properties........................ 53 6.2 Pollution of the indoor air .............................................................................. 54 6.3 Concentration of pesticides in layers of settled dust ..................................... 60 6.4 Concentration of pesticides in selected objects ............................................ 61
7
Assessment of endangerment to health ................................................................ 65 7.1 Precautionary measures ............................................................................... 65 7.2 Policy and guidelines for decontamination.................................................... 66
8
Procedures for cleaning and decontamination ...................................................... 67 8.1 Procedures for dry-cleaning.......................................................................... 67 8.1.1
Suction Techniques ................................................................................ 67
8.1.2
Laser-cleaning ........................................................................................ 69
8.1.3
Thermal procedures ............................................................................... 69
8.1.4
Freeze-drying procedures ...................................................................... 70
8.1.5
Ultrasonic waves .................................................................................... 70
8.1.6
Solid carbon dioxide ............................................................................... 71
8.1.7
Supercritical carbon dioxide ................................................................... 71
8
8.2 Procedures for wet cleaning ......................................................................... 71 8.2.1
Cleaning agents...................................................................................... 72
8.2.2
Procedure with vacuum extraction and washing .................................... 72
8.2.3
Techniques for single objects ................................................................. 73
8.3 Decontamination with supercritical carbon dioxide ....................................... 73
9
8.3.1
Properties of supercritical carbon dioxide............................................... 74
8.3.2
Diagram of a Super Fluid Extraction (SFE) plant.................................... 76
8.3.3
Present use of SFE in industry ............................................................... 77
8.3.4
Current state of decontamination in works of art and cultural heritage ... 77
Selection of ethnological materials and objects..................................................... 84 9.1 Preliminary considerations............................................................................ 85 9.2 Description of composition and compounds of materials and objects........... 86 9.3 Description of the condition of materials and objects.................................... 88 9.4 Production techniques .................................................................................. 88 9.5 Analytical examination of selected materials ................................................ 88
10
Preparation of objects and materials for experiment ............................................ 91 10.1 Photographic documentation of samples and reference samples............... 91 10.2 Analytical determination of pesticides....................................................... 104 10.3 Preventive and precautionary measures .................................................. 105
11
Experiment A for characterizing the changes in materials in a 10 L high-pressure extraction (HDE) plant for scaled-up experiments ........................ 106
9
11.1 Process diagram of the plant .................................................................... 106 11.2 Parameters during experiment.................................................................. 107 11.3 Course of experiment A with a 10L plant .................................................. 108 11.4 Interpretation of test results ...................................................................... 110 11.4.1 Visual evaluation ................................................................................ 110 11.4.2 Microscopic examination .................................................................... 113 11.4.3 Analytical investigations ..................................................................... 115 11.5 Discussion of the results ........................................................................... 121 11.5.1 Evaluation of the susceptibility of materials and objects to extraction with SC-CO2 in a high-pressure plant for scaled-up experiments....... 121 11.5.2 Potential measures to prevent changes in materials .......................... 122 11.5.2.1 Exclusion of unsuitable objects before the process...................... 123 11.5.2.2 Prior treatment with film former .................................................... 123 11.5.2.3 Prior treatment with cyclododecane ............................................. 123 11.5.2.4 Change of parameters during the procedure................................ 124 11.5.3 Regenerative treatments after changes of materials .......................... 124 11.5.3.1 Recirculation of lipophile substances ........................................... 124 11.5.3.2 Restoration of the bonding ........................................................... 125 11.5.3.3 Restoration of gloss...................................................................... 125
10
12
Experiment B for determining the level of elimination of pesticides in a 150 mL high-pressure view cell ....................................................................................... 126 12.1 Process diagram of the 150 mL laboratory plant ...................................... 126 12.2 Process parameters.................................................................................. 127 12.3 Course of experiment B with a 150 mL laboratory plant ........................... 127 12.4 Interpretation of test results ...................................................................... 128 12.4.1 Visual evaluation ................................................................................ 128 12.4.2 Microscopic examination .................................................................... 130 12.4.3 Determination of the amount of pesticides and the level of decontamination ................................................................................ 132 12.5 Discussion of the results ........................................................................... 134
13
Conclusions......................................................................................................... 136
14
Indices................................................................................................................. 141 14.1 Index of illustrations .................................................................................. 141 14.2 Index of Sources of Illustrations................................................................ 146 14.3 Index of Tables ......................................................................................... 150
15
Bibliography ........................................................................................................ 152
16
Appendix ............................................................................................................. 179
17
Declaration .......................................................................................................... 207
11
1
Introduction
Publications and reports about collections in natural history museums, ethnological museums and historic plant collections worldwide state that objects and materials formerly treated with pesticides and heavy metal compounds against pests present a serious problem and a potential health risk to those who are presently handling and working with these items. Measurements undertaken at the Ethnological Museum in Berlin (Ethnologisches Museum zu Berlin, henceforth EM) with about 500,000 items in its holdings have shown that two-thirds of the collections are contaminated with organic pesticides and heavy metal compounds. There is little knowledge about the previous treatment of objects, which are poorly documented anyway. Chemical analysis represents the most reliable method to determine and to analyze the various kinds of organic pesticides and heavy metal compounds. Different chemical technology and analyses show the contamination of an object in its various degrees. Currently, conservators are trying to reduce the mass of heavy metal compounds and pesticides on objects primarily by cleaning the surfaces and by diminishing the dust in storage cupboards and facilities, due to the lack of other possible methods. Unfortunately, poisonous substances embedded in the matrix of items cannot be removed by cleaning the surfaces alone. Therefore, a method of detoxification must be developed that would decontaminate not only individual poisoned items, but also whole collections. Super fluid extraction (SFE) with carbon dioxide offers a method, which would allow decontamination of vast amounts of objects. To apply this method, a profound and basic knowledge about the properties of the different materials is necessary, in order to prevent any possible damage to those objects and materials which are sensitive to SFE. These materials should be excluded from the process from the viewpoint of conservation and at least from the present viewpoint of research.
12
2
Approach
This thesis tries to get answer to whether or not SFE may be applied to detoxify cultural heritage and works of art, as they exist in ethnological, natural history- and historic plant collections. Thereby the assessment of single objects is of secondary importance. Thus this procedure exists for a long period of time in food industry, the development of a method and the scrutiny of its effectiveness on objects from our cultural heritage form the framework of the following assessments. The probably causing of damage on works of art that happens temporary, lasting or reparable by means of the method belongs to the basic questions. The procedure of detoxification will be explained here briefly, in order to provide an understanding of the course of this method. Due to the combination of materials and components involved in production or provided in their natural state, ethnological objects often present specific problems for the decontamination of pesticides and heavy metal compounds. Their significance in the work of conservators is examined within the framework of inorganic and organic materials, out of which objects in natural history collections as well as in ethnological museums and historic plant collections are composed. All examinations and analyses were carried out on objects and materials from the Ethnological Museum in Berlin. The consequences of SFE treatment with carbon dioxide is estimated and assessed in the following. The final discussion demonstrates the current spectrum of knowledge on materials that can undergo the process of SFE with carbon dioxide without incurring any damage. Also under concern will be those materials that should be handled with caution and preferably excluded from extraction.
13
3
History of pest control of ethnological objects
3.1
Sources of pest control
Techniques in preventive measures against pests were already in use 3000 years ago in Egypt and Greece, and 2000 years ago in China.1 Human and animal bodies as well as artifacts were treated with different substances consisting of organic and inorganic compounds against pests with varying success. In the course of history, a vast number of items treated in this manner found their way into so called “chambers of curiosities” and were later acquired by museums and institutions with botanical-, natural history- and ethnological collections all over the world. BOLZ describes this development using the State Museums in Berlin, (Staatliche Museen zu Berlin, henceforth SMB) as an example.2 In many cases stored and exhibited collections as well as single objects had continuously been treated with pesticides, heavy metal compounds and other substances. In view of the immensity of this problem, the following paper will focus as an example on the consequences for objects treated with pesticides and heavy metal compounds. However, it would be remiss of me not to mention that some inventions against pests such as arsenic soap were trend setting for generations of taxidermists and conservators.3/4 The properties, formulations, applications and toxicity of contaminants containing chlorine compounds and heavy metal compounds have been described and discussed extensively in numerous articles.5 POOL et al. have carried out a very commendable work by compiling pesticides and heavy metal compounds with respect to their history, characters, method of application, target pests, field Half-Life,
1
MECKL 2004, 89.
2
BOLZ 2003.
3
Arsenic soap, discovered by the pharmacist Jean Bécouer (1718-1777), consists of camphor, arsenic oxide, soap, potash, and lime powder. It was used regularly until the beginning of the 20th century for dry preparations.
4
MECKL 2004, 91 – 92.
5
cf. RATHGEN 1898, ANDRES 1919, BOLLE 1919, RATHGEN 1924, GUGLIA 1954, RIEDERER 1977, CHILD and PINNINGER 1992, ELERT 1994, GOLDBERG 1996, UNGER A. 1998, BUNDESGESUNDHEITSBLATT 2000, KRESS 2000, HAWKS 2001, KEARNEY 2001, SIROIS et al. 2001, PÜSCHNER 2002, LINNIE 2004, BOYER et al. 2005, POOL et al. 2005, SCHIEWECK and SALTHAMMER 2006.
14
persistence and use. This compilation is presented here in Table 1 and Table 2 (see appendix pp. 180-186). Various treatments with these substances were often completed by applying different coatings such as adhesives, waxes, linseed oil, resin, varnish or spirit lacquer.6 Today a broad spectrum of methods and procedures for determining these substances are offered within the framework of environmental analysis. These are compiled in Table 3. The choice of the analytical method to be employed is dependent upon the particular circumstances of contamination in museums enclosures and their collections. Hence, this must be decided from case to case.7 Table 3: Analytical procedures and methods for the determination of pesticides and heavy metal compounds
Heavy metal compounds Methods and Procedures Atomic Absorption Spectroscopy Atomic Emission Spectroscopy Inductively Coupled Plasma Mass Spectrometry Arsenic Spot Test
Abbrevation AAS AES ICP/MS
Pesticides Methods and Procedures Gas Chromatography Gas Chromatography/Mass Spectrometry X-Ray Fluorescence Spectroscopy X-Ray Electron Spectrometry X-Ray Photoelectron Spectroscopy Fourier Transformation Infrared Spectrometry Thin-Layer Chromatography
Abbrevation GC GC/MS XRF XES XPS FT-IR TLC
6
BOLLE 1919, 115.
7
cf. TÉTREAULT 1992, CALDARARO et al. 2001, GIBSON and BROKERHOF 2001, PALMER 2001, SIROIS and SANSOUCY 2001, BARTOLL et al. 2003, KLAUS et al. 2005, ODEGAARD et al. 2005.
15
As a result of recent knowledge gained about health hazard of pesticides and their deteriorating effect on materials, new methods of treatment such as integrated pest management, freeze-drying, low and high temperature,8 high temperature pest eradication on DNA,9 photo destruction,10 biological pest control11 or genetic manipulation on plants,12 came into use or are still at a developmental stage. Therefore, they will be mentioned here only briefly. Although often the documentation on single objects applied with pesticides is scant and insufficient, there is an increasing awareness of the risk to health when handling these substances, which has recently led to variously and different studies, surveys and reports at a national and international level. These developments will be introduced in the following.
3.2
Pest control in German collections
Documentary material and surveys have enabled an insight and an overview of the use of pesticides and heavy metal compounds in the following German collections. D. LEHMANN recommends the use of naphthalene and 1,4-dichlorobenzene (PDB) against moths.13 These substances were placed on shelves next to wrapped historic textiles. Further on he suggests applications that should be carried out using Eulan, Eulan U33 and Eulan BLS, before textiles are exhibited.14 If these treatments cannot be employed, a coating of dichlorodiphenyltrichlorethane (DDT) or Diazinon (0,0Diethyl-0-(2-isopropyl-6-methyl-4-pyrimietiryl)-monothiophosphat) should be sprayed upon the objects as well as in “all affected rooms, including walls, floors, shelves, cupboards both inside and out, and all other fixtures” at an interval of one year.15 In addition, he emphasizes an essential treatment with Eulan (derivates of 2,4,5-
8
cf. ELERT 1994, KNEPPEL 1994, ODEGAARD 2001, UNGER W. 2002, CARRLEE 2003, RUMBALL, PINNIGER 2003, WAGNER et al. 2005.
9
ACKERY et al. 2004.
10
ASMUS 2001.
11
WEIDEMANN 2005.
12
BOWN et al. 2002, HALL et al. 2004, WÜSTHOF 2005.
13
LEHMANN, D. 1964, 15.
14
ibid. 16 - 17.
15
ibid. 17 - 18.
16
trichloraniline chloromethyl sulphonate)16 for the protection of historic textiles against all kind of pests in the Islamic Department of the SMB West.17 Also at the National Museum of German Art and Culture (Germanisches Nationalmuseum) in Nürnberg it has been determined that a collection of c. 13,000 garments and fabrics are polluted with DDT.18 Analyses conducted by screening dust and indoor air19 showed that in addition 1,4-dichlorobenzene, lindane and naphthalene were also present in high concentrations.20 Within the project “Pedekon”, supported by the German Environmental Foundation (Deutsche Bundesstiftung Umwelt or DBU), the possibilities of detoxification with supercritical carbon dioxide on damaged textiles were assessed. The results will be described in Chapter 8. Examples of the preservation of wood against pests and their effects can be found in different museums. In the storage areas for furniture of Schloss Nymphenburg, belonging to the Bavarian Administration of State-owned Palaces, Gardens and Lakes (Bayerische Verwaltung der Staatlichen Schlösser, Gärten und Seen), pesticides such as DDT, pentachlorophenol (PCB) and lindane had been sprayed as a preventative measure yearly. As a consequence, an extensive amount of furniture and other items had to be dry-cleaned and covered. These objects were taken out of storage and waited for return to their facilities and kept elsewhere until their return to the original storage place. In the meantime those facilities had to undergo thermal decontamination.21 At the Hessisches Landesmuseum in Kassel there is no clarity concerning the number of wooden objects that are polluted with pesticides. However, old invoices from the conservation laboratory show that more than 600 liters of Xylamon, a wood preservative that first contained chloronaphthalene and then other biocides, were ordered between the years 1978 and 1995. Later, from 1999 to 2004, measurements
16
LEHMANN, D. 1974, 35 - 36.
17
At the end of World War II, the State Museums in Berlin were separated into the East and the West museum, from 1947 until the reunion of the State Museums in Berlin Stiftung Preußischer Kulturbesitz in 1990. See: Die Stiftung Preußischer Kulturbesitz, Teil 1, 1994, 33-38.
18
KRESS 2000.
19
ibid. 42 - 44.
20
ibid. 47 - 61.
21
PIENING 2001.
17
of dust, indoor air and selected wooden objects showed significant contamination with pentachlorophenol (PCP), lindane and low counts of PCB.22 In the former German Democratic Republic Hylotox 59, another wood preservative containing DDT and lindane as the main compounds was frequently used.23 It was detected in a commemorative epitaph with eight sculptures dated to the 16th century, which is in the holdings of the Landesamt für Denkmalpflege Sachsen in Dresden.24 The presence of Hylotox could also be detected in a Baroque prospect with 196 wooden parts from the 18th century that belongs to the Brandenburgisches Landesamt für Denkmalpflege in Wünsdorf.25 Current cleaning treatment with organic solutions has proven to be less effective and later crystallization occurred once again.26 There are many reports and analyses from natural history collections of the former German Democratic Republic, which provide further information on this problem. At the Museum of Natural History of the Humboldt University in Berlin (Museum für Naturkunde der Humboldt-Universität zu Berlin) supposed risks to the health of staff members led to measurements in the early 1980s and again in the early 1990s.27 Samples were taken from dust and indoor air in offices as well as in the collection rooms. Lindane, formaldehyde, xylene, naphthalene, phenol and compounds of arsenic were found to be clearly below the level for legal standards of hazardous substances.28 A study project on the respective natural history museums in Dresden, Chemnitz, Leipzig, Görlitz and Augustusburg was carried out by the Saxonian
Institute
for Occupational Safety and
Health
(Landesinstitut
für
Arbeitsschutz und Arbeitsmedizin in Sachsen).29 Health hazards for the staff and taxidermists dealing with animal preparations that were contaminated with heavy metal compounds and pesticides such as lindane, permethrin, and DDT were detectable even in dust and ranged from low to high levels. Further, the indoor air
22
KLINZMANN 2005, 1 - 3.
23
UNGER A. 1998, 187.
24
UNGER A. 2003, 9 - 10.
25
ibid. 34 - 35.
26
ibid. 9.
27
BADER 1999.
28
ibid. 2.
29
LEIMBROCK and WAGNER 1998.
18
was polluted with lindane, DDT, permethrin, pyrethrum, PDB, naphthalene, camphor, Dichlorvos and carbon disulphide.30 Detailed information and measurements of the contamination in German ethnological collections can be found in the Adelhauser Museum of Ethnology and Natural History (Adelhauser Museum für Völkerkunde und Naturkunde) in Freiburg. Examinations between 1990 and 1996 and again in 2002 in storage areas, exhibition rooms and rooms for preparing exhibitions revealed the presence of chloronaphthalenes, lindane, PCP, PDB, permethrin, arsenic and mercury. These substances were found in dust and indoor air ranging from low to high levels. The results consequently led to drastic policies in the handling of collections in storage areas for staff and visitors. Now general access to the examined facilities has been reduced to a minimum level in compliance with a protocol with safety guidelines.31 Nevertheless, it must be noted here that measurements taken again in 2002 of indoor air in an area with dry-cleaned and conserved items as well as with new accessions was polluted to a high level with lindane once more.32 The complete demolition of storage facilities was carried out after an investigation of the Bremer Umweltinstitut in the Übersee Museum in Bremen.33 Namely, there analysis of indoor air and dust in storage facilities showed that since the beginning of the 1950s pesticides including PCP, lindane, DDT, PDB,
Figure 1: Wooden votive tablet, so called Postentafel, treated at the Überseemuseum Bremen with PCP (formulation Xylamon)
chloronaphthalenes and various pyrethroids34 were applied regularly by conservators as well as taxidermists (see Fig. 1 p.19). The pollution level ranged from low to high and in the entire storage area lindane was found in indoor air at high levels. As a consequence, the storage building was torn
30
Ibid. 114 - 120.
31
HARTER 2005, 1 - 7.
32
ibid. 8.
33
KROOß and STOLZ 1993.
34
ibid. 301 – 303.
19
down in 1995. Since then the collection has been kept in a new building across the street, after c. 65,000 objects were subjected to an extensive dry-cleaning process.35 At that time measurements in the exhibition areas were not taken, and moreover, for reasons of cost objects have not been analyzed at all since then.36 KROOß and STOLZ assume that similar problems of contamination are not only present in this particular museum, but in others as well. Evidence for this assumption is provided at the Lower Saxony State Museum Hanover (Niedersächsisches Landesmuseum Hannover). HARTMANN reports that carbon disulfide was volatilized there to control pests.37 Yet, the full extent of the use of pesticides first came out within the scope of an interdisciplinary investigatory project. The indoor air and settled dust were analyzed in storage- and exhibition rooms, showcases and dioramas.38/39 Although lindane is not applied anymore today, it was still found in small bags that were left in display cases in which prepared insect were exhibited.40 Increased concentrations of PDB, lead, arsenic and chlorine attested their use against pests and fungi. Reactive chemicals were also found in the Department of Ethnology.41 To summarize, the primary cause for indoor air pollution was considered to be the wide range of pesticides used in the past and in the present to protect artifacts against pest infestation.42 ELERT provides the summary of an anonymous questionnaire amongst eleven small, medium and large ethnological collections in Germany. Her survey leads to the clear statement that all collections have long treated their holdings with pesticides.43 The majority of those interviewed maintained that accessions and loans
35
Personal comment kindly provided by Conny Ammermann and Thomas Schelske, Übersee-Museum Bremen, 2004.
36
KROOß and STOLZ 1993, 303 - 304.
37
HARTMANN 1955a, 23.
38
SCHIEWECK et al. 2005a.
39
SCHIEWECK et al. 2005b.
40
ibid. 6105.
41
ibid. 6098.
42
ibid. 6106 - 6107.
43
ELERT 1994, 114 - 119.
20
were the sources for pest infestation.44 Table 4 shows recent preparations and procedures used against pests according to ELERT`S assessment in 1994. Table 4: Preparations and their use in German ethnological collections after ELERT 1994. Preparations/Treatments
Substances
Mothballs- and paper Freeze-drying Wood Preservatives Gas treatment with toxic gas Gas treatment with inert gas Vapourizing Pest-strips Thermal treatment Vacuum process
Chlorpyrifos, Empenthrin, Naphthalene, PDB
3.3
Permethrin Methyl Bromide, Carbon Disulphide Carbon Dioxide, Nitrogen Pyrethroides, Pyrethrum, Dichlorvos Lindane in the past, Pyrethrum at present
Use in % 45 36 36 27 27 27 18 18 9
Pest control in European collections
FARMAKOWSKIJ presented a historical manual, which has been translated by J.LEHMANN in a summarized version.45 In the manual FARMAKOWSKIJ provides a profound view into the methods of conservation and restoration that were employed in the former Soviet Union during the first half of the 20th century. He offers guidelines for using insecticides, such as thymol, salicylic acid, phenol, and zinc sulphate, against microorganisms on leather and on wood. According to him, the vapor of thymol or formaldehyde should be sprayed on paper to prevent infestation. Entire rooms ought to be vaporized with a solution of 40 % formaldehyde per m3.46 Naphthalene is recommended being replaced by PDB to protect textiles from moths, as the efficacy of the former is controversial.47 Due to the long time for transport of objects from archaeological excavations, field laboratories are compelled to be equipped with salicylic acid, thymol, and phenol.48 For all types of insects Farmakowskij observes that treatment with fumigants, e.g. hydrogen cyanide,
44
ibid. 116.
45
LEHMANN J. 2005.
46
ibid. 56 – 57.
47
ibid. 60.
48
ibid. 59.
21
ethylene oxide and chloropicrin, and with carbon tetrachloride and dichloroethane as organic solvents is the only satisfactory method against infestation. He discusses a negative effect of chloropicrin on materials and colors and advises extreme caution.49 Although no chemical were realizable at his time, in his farsighted outlook he includes controlled high temperatures, the use of microwaves and predators (insectivores) that exterminate wood destroying insects.50 J.LEHMANN also came into contact with pesticides while working with explosive substances like carbon disulfide at the National Museum in Prague until late in the 1960s.51 Admittedly, the application was dangerous, but very efficient, and treated materials showed very view side reactions. Wooden objects and textiles have been treated systematically in this way.52 For that purpose, a fumigation chamber was developed by LOSOS. It could be used for carbon disulfide, sulfur dioxide, bromomethane, ethylene oxide, acrylonitrile, chloropicrin,
ethylene
dichloride
(dichloroethene),
tetrachloromethane
and
formaldehyde. Figure 2 and 3 (see p. 23) show two different types of chambers for both small and large objects.53 Nitrobenzene (oil of mirbane) was handled carelessly due to its seemingly harmless, almond-like scent, as recorded by J. LEHMANN during her stay at the entomological collection at the Schlesisches Heimatmuseum in Opava.54
49
ibid. 60.
50
ibid. 60.
51
LEHMANN J., 2005, 62.
52
Personal comment kindly provided by mail by Jirina Lehmann, 2005.
53
LOSOS 1959.
54
Personal comment kindly provided by mail by Jirina Lehmann, 2005.
22
Figure 2: Wooden gasholder cabinet with removable trays for large objects, size: c. 100 x 100 x 80 cm
Figure 3: Metal gasholder cabinet with removable rack for small items, size: c. 100 x 100 x 80 cm
An early survey by GUGLIA from Vienna points out that the use of inorganic chemical products has gotten out of control in European entomological collections.55 The current preparations in use are designated as Globol (PDB), Hexol (naphthalene), Mirbanoil (nitrobenzene), Jacutin (mainly γ-hexachlorocyclohexane) and Toxol (DDT), chloroform, ammonia solution, hydrogen cyanide, pure sulfuric ether (diethylether), compounds of ester, sulfur dioxide, nicotine, naphthalene, carbon dioxide, DDT and mercury.56 GUGLIA is probably early with his observations and has raised alarm amongst colleagues and other persons about the serious health hazards caused by substances described in his article. His survey resulted in various individual reports by colleagues worldwide, which supplied proof of temporary or chronic diseases following contact with chemical substances against pests.57 He defines poisoning with Globol as: “Maladies professionelles inapparents”.58 From Switzerland SCHLÄPFER and HUBER give a general report about the presence of mercury, arsenic, PCP, lindane, and DDT in collections in museums of
55
GUGLIA 1954.
56
ibid. 194 - 199.
57
ibid. 200 - 202.
58
ibid., after Heim de Balsac, 196.
23
natural history and ethnology. This long neglected aspect gives both authors reason to remark that in the case of health hazards there is a need for action in many of these museums.59 At the Danish National Museum and the Danish Museum of Arms and Uniforms it was common in the 1950s and 1960s to dispense pesticides liberally throughout storage- and exhibition rooms.60 In 1983, before repatriating artifacts from Denmark to Greenland, dust from the surface of selected objects was analyzed and revealed to contain DDT in various concentrations. Subsequently, the entire facilities of the museum were tested for the presence of PDB, naphthalene, DDT and methoxychlor.61/62 An example for polluted herbarium specimen is supplied by PUREWAL from the National Museum and Galleries of Wales. The residues of mercury, arsenic, barium and naphthalene were identified on specimen, and aside from the last they were found in high concentrations. Biological monitoring indicated that the staff working on the historic plant collection was contaminated with arsenic and mercury. Safety standards were expended to reduce the contamination, including the wear of protective clothing while working with polluted specimen. Within one year’s time the repetition of biological monitoring provided evidence that all elevated levels had returned to normal among all members of staff.63 Research in literature and a survey amongst 22 key botanical institutions in 12 countries in the United Kingdom and abroad revealed the use and application of 16 different chemicals on herbarium material.64
59
SCHLÄPFER and HUBER 2000, 21 - 22.
60
GLASTRUP 2001.
61
GLASTRUP 1987.
62
SCHMIDT 2001.
63
PUREWAL 2001, 77 - 86.
64
ibid. 79.
24
3.4
Pest control in U.S. American and Canadian collections
GOLDBERG provides a comprehensive historical survey of the constant use of pesticides and heavy metal compounds at the National Museum of Natural History of the Smithsonian Institution.65 Among other things, the survey bases up on HOUGH’S recommendations for protecting museum items from insects. There HOUGH provides to apply woodwork, basketry, textiles and botanical specimen with mercury(II)chloride (sublimate).66 Arsenic soap, naphthalene, carbon disulphide, chloroform, strychnine and benzine also come under his consideration.67 HAWKS and HAWKS and MAKOS have provided access to the sources of contaminated ethnographic material over the entire range of public and private museums and collections through the United States.68 Pesticides and heavy metal compounds are listed with their health hazards,69 and it is indeed interesting that as early as the 18th century mercury compounds were recorded as being “a dreadful poison”.70 Although the specific use of chemicals is not documented on certain objects,71 tags were found at the National Museum of Natural History, that are attached to objects and designated with a skulland-bones sign, as well as the word “poisoned” (see Fig. 4).72
Figure 4: Gut skin garment panel with poison tag, dated September 12, 1884, from the collection of the Anthropology Department, National Museum of Natural History, Smithsonian Institution
65
GOLDBERG 1996, 23 - 43.
66
HOUGH 1889, 549.
67
ibid. 551 - 556.
68
HAWKS 2001, HAWKS and MAKOS 2001.
69
GOLDBERG 1996, 24 – 27.
70
ibid. 23.
71
ibid. 28.
72
ibid. 32.
25
In an early instruction, in the winter of 1909-1910, BOETTCHER recommends a treatment with paraffin against animal depredations for tusks that arrived from the Smithsonian African Expedition in the United States National Museum.73 Considering that contamination is not an issue that can be confined to one museum, analysis from the San Francisco State University Chemistry Laboratory were conducted from DAVIS et al., and actions recommended for contaminated museum materials were compiled.74 A comprehensive description of health hazards caused by pesticides is provided by KEARNEY in an overview of risk assessment of acute and chronicle health effects, based on the various types of substances and their application techniques.75 However, in American and Canadian museums with Native American cultural heritage in their holdings, there is another very delicate and specific aspect that is problematic.76 Since the pronouncement of the Native American Graves Protection and Repatriation Act (NAGPRA) in 1990,77 some of the precious ancestral material has been returned to the respective Native tribes “clothed in dangerous invisible wrappers”, that is, toxic pesticides.78 Therefore, the contaminated artifacts often cannot be used again in a cultural context.79 HOSTLER et al. describe the difficulties in handling this material at ceremonies, and they discuss the responsibilities of those persons who hand over the artifacts.80 As a consequence, the Arizona State Museum has developed a checklist for those persons who must handle repatriated objects.81 Inevitably, small and large museums will have to deal with this specific issue and its consequences. For example, the Phoebe Hearst Museum in Berkeley, with a collection of North American Indian heritage disposes over information pertaining to historical treatments on their objects with PDB, naphthalene, carbon tetrachloride,
73
BOETTCHER 1912, 702 - 703.
74
DAVIS et al. 2001, 96 – 99.
75
KEARNEY 2001, 44 – 53.
76
FRANKFURTER ALLGEMEINE ZEITUNG 2003.
77
JOHNSON and HENRY 2002, 673 - 674.
78
DAVIS and CALDARARO 2000, 46.
79
SADONGEI et al. 2005, 1 - 4.
80
HOSTLER et al. 2001, 54.
81
ODEGAARD and SADONGEI 2001.
26
DDT, dichlorvos, methoprene, mothproofing sprays and arsenic.82 Also seventeen artifacts from the Peabody Museum in Harvard that had been repatriated to the Hoopa Tribal Museum in California were tested at the San Francisco State University Chemistry Laboratory, and arsenic and pesticides were found in all cases.83 Furthermore, concerns of the Hopi Pueblo tribe at the Denver Museum of Natural History led HOWE et al. to conduct a project for over three months’ time, during which 512 objects from different North American Native nations were scrutinized. The results of tests on mercury and arsenic were sent in reports to the Native representatives and to the National Park Service NAGPRA Office.84 In large collections such as the North American Ethnographic Collections in the Field Museum in Chicago, it is very helpful to have a database, in which specific groups
of
objects
or
materials
are
classified according to their contamination. This allows an overview of objects, trends, collectors,
etc.
with
a
high
risk
of
contamination.85 Swab testing for residual arsenic (see Fig. 5) has led to positive-
Figure 5: Arsenic swab test carried out at a parfleche in the collection of the Chicago Field Museum
and negative-determined accessions per decade (see Table 5 p. 28) and per artifact type (see Table 6 p. 29).86 The Analytical Research Laboratory of the Canadian Conservation Institute analyzed over 1100 natural history specimen and 600 artifacts in Canadian Aboriginal Collections.87 The result of this analyses showed that 80 % of the natural history
82
Personal comment by e-mail kindly provided by Madeleine W. Fang, conservator at the Phoebe Hearst Museum of Anthropology, Berkeley/CA, USA, 2006.
83
CALDARARO et al. 2001, 55 – 62.
84
HOWE 1999, 28 – 31.
85
KLAUS et al. 2005.
86
KLAUS et al. 2004.
87
SIROIS 2001, POULIN 2004.
27
specimen contained arsenic and mercury or both. Further, 23 % of the artifacts of the First Nations and anthropology specimen were registered as being contaminated.
Table 5: Accessions per decade from 1890-1999 being tested positive and negative for arsenic at the Chicago Filed Museum, Ohio, USA
28
Table 6: Artifacts per artifact type being tested positive and negative for arsenic at the Chicago Filed Museum, Ohio, USA
3.5
Discussion and assessment
There are two important aspects that were trend setting for the availability of chemical substances against pests worldwide. Firstly, during the 19th century an increasing amount of pesticides was invented and distributed through specialized trade. Secondly, Rathgens’ studies and his manual, Die Konservirung von Alterthumsfunden, of 1898 set a landmark in the history of conservation and restoration worldwide. For chemists like Schmidt in Munich, Rosenberg in Copenhagen, Ruzopulos in Athens, Scott in London, Fink and Nichols in the United States, and Marr, Fresman and Oldenburg in the former Soviet Union this publication represented the base of knowledge in conservation, and enabled them to revise and expand it with their own research and practice.88 Thus, this demonstrates that pesticides and heavy metal compounds had been an element of pest control in collections all over the world for a long period of time. The awareness of their danger followed only later, when health hazards through chemicals came more into focus, and analytical methods in the natural sciences became more precise. Of special
88
cf. LEHMANN J. 2005.
29
concern is the repatriation act in the USA and in Canada, as it adds the risk of health hazards for Native people. There, concerns of responsibility and moral duty towards those who receive their ancestral heritage are an inalienable obligation. The entire spectrum of the aspects discussed above makes scientific research on detoxification of such poisoned artifacts absolutely imperative.
30
4
Damage to collections with pesticides
In the following a short review will be made of different kinds of damage caused by pesticides themselves or the interaction between materials and pollutants to the holdings in storage and exhibitions. It bases upon exemplary reports made on specific collections and materials.
4.1
Damage to German collections
ELERT cannot rule out the possibility of an exchange treated
between
with
materials
chemical
and
objects
substances.89
This
implication could be confirmed by KRESS, when she observed a clear context between damages
like
inhomogeneous
a
whitish
change
of
blooming, colors
an
(which
remains as stains on garments), the loss of substance, and the absence of the surface web on fabrics.90 However, the damages could not be related to single substances by KRESS.91 She estimates that an interaction of light and pesticide residues probably is linked with the fading of colors. An investigation on fading colors is found in HAHN. He examines ethylene oxide and hydrogen cyanide as agents for fading colors in materials like paper and parchment, respectively in books.92
89
ELERT 1994, 51.
90
KRESS 2000, 29 - 31.
91
ibid. 61.
92
HAHN 1997/1998, 204.
Figure 6: Wooden sculpture with DDT blooming
31
Chemical reactions are mostly seen in organic dyes that were extracted from Brazil wood, elderberry, madder and orchella. Copper pigments react with hydrogen cyanide to produce copper cyanide complexes. HAHN propounds that these chemical changes may be able to accelerate the degradation process.93 Within the DBU project of A. UNGER et al. another typical phenomenon, the formation of white crystals upon the surfaces of wooden sculptures (see Fig. 6 p. 31), could be clearly identified as DDT blooming caused by excessive application of oily wood preservatives.94
4.2
Damage to European collections
RYHL-SVENDSEN also noted the phenomenon of white crystals forming on ethnographic objects during his assessment on showcases and the processed materials as sources of contaminants in European museums and collections. In one case this effect was visible to such an extent that the interior of the entire installation was completely covered with crystals.95 The grayish black stains from mercury compounds on herbarium sheet labels in botanical collections drove HAWKS and BELL to examine in detail and to find solutions for their removal. Their results will be described in Chapter 8.96 In addition, PUREWAL noted yellow tidemarks on sheets of natural history specimen.97 DAWSON and LINNIE consider chemicals to be the cause of the damage too and the spoiled appearance of museum items.98 STÖSSELSITTIG et al. has drawn our attention to the fact that fur may bleach out after it is treated with PDB. This substance is able to release chlorine ions, which may destroy pigments in the keratin of the fur.99
93
ibid. 209.
94
UNGER et al. 2001, 259.
95
RYHL-SVENDSEN 2001.
96
HAWKS and BELL 1999.
97
PUREWAL 2001.
98
DAWSON 1987, LINNIE 2004.
99
STÖSSEL-SITTIG et al. 2006, 33.
32
4.3
Damage to U.S. American and Canadian collections
At a very early point in time HOUGH recognized that mercury chlorides affect animal skins and are the cause for the skins becoming dark and stiff.100 His knowledge about the use of mercuric chloride and arsenic trioxide at the National Museum of Natural History of the Smithsonian Institute was proven and confirmed several years later by the work carried out on a pair of boots from the Aleutian Islands. The black pigments on an appliqué band on the boots turned out to be potassium. The presence of this substance was attributed to the use of potassium saltpeter (potassium nitrate) and potash (potassium carbonate). Both compounds were sometimes mixed with arsenic trioxide and used as a solution applied to skins.101 DAWSON and BAKER et al.102 indicate that chemicals and fumigants used as pesticides “can cause a wide variety of changes in metals, waxes, resins, oils, pigments, dyes, cellulose, and protein-based materials”.103 But, unfortunately, the cause of stains, tide-lines and areas of white crystalline blooming, which can be identified on museum items, often is not clearly attributable.104 Vapors of pesticides may also damage objects made of plastics. DAWSON observed a shrinking effect, dyeing and softening of different types of plastics, while they were exposed to high concentrations of PDB, naphthalene, Dichlorvos and thymol.105 FENN applied the modified Oddy-test to get proof of the impact of pesticides on various plastics. No change was determined with Dichlorvos on polystyrene, polymethylmethacrylate and on polycarbonate. But the adsorbed pesticides colored black copper foils and caused a change in lead- and zinc samples. With the exception of cellulose nitrate that yellowed through camphor, no damage was determined from naphthalene, camphor, thymol, lavender oil and PDB on works of art. Contaminated plastics did not cause an
100
HOUGH 1889, 554.
101
BOULTON 1986, 6-7.
102
DAWSON 1988, BAKER et al. 1990.
103
cited after GOLDBERG 1996, 38.
104
ibid. 38.
105
DAWSON 1984.
33
adverse effect on metal samples, and ammonia did not affect plastics and metal samples at all.106
4.4
Discussion and assessment
It is a matter of fact that is little known about the potential changes that can occur through residues of pesticides and heavy metal compounds in museum items and materials. Scientific research in this area must be regarded at most as fleeting visit to single objects and materials, and there is an urgent need for further study. To clarify the described phenomena in this chapter, individual investigation is always necessary. Finally, the long-term availability of collections at their accustomed facilities, combined with a largely and often unknown conservation treatment and a loss of its documentation, often makes it difficult for museum professionals to distinguish damages due to pesticides from damages caused by other agents.
5
Chronology of the use of pesticides on collection items at the Ethnological Museum in Berlin
In the following attention will be directed towards: the history and course of development of measures in conservation practices and procedures, measures against pests in materials, and temporary and/or permanent changes in conservation science. Thereby, the focus will be upon practices in pest control at the EM.
5.1
Preparations and procedures employed
As is the case in other museums, the archival documentation on the use of pesticides and fumigants is even very poor at the EM. Thus, the assessment here can only present a mere aspect of all the changes in conservation methods on pest control provided by the SMB, which were carried out in particular at the EM.
106
FENN 1995.
34
5.1.1 Preparations employed during collection trips in 19th century It is briefly noted in reports and diaries from early collection trips, field work and travels of ethnologists and collectors, among others KARL VON DEN STEINEN and THEODOR KOCH-GRÜNBERG, that their first-aid kit included arsenic trioxide, naphthalene, camphor, ammonia, carbolic acid, alcohol, theine, nicotine, quinine and beijú.107/108 However, there is little information about the actual use of these preparations to repel pests. Only WILHELM KISSENBERTH complains in one of his letters about cockroaches ignoring naphthalene, pepper and zachenlin in the crates.109 5.1.2 Preparations from late 19th century until World War II The archives of the EM, at that time “Königliches Völkerkundemuseum Berlin” provide information about the general use of pesticides and heavy metal compounds. Mercury(II)-chloride (sublimate) was applied to fur, feathers and woolen objects.110 For single endangered items originating from Africa or entire collections from Australia, VON LUSCHAN, director of the Department of Africa and Oceania from 1904–1910, ordered the use of sodium arsenate in several cases to repel pests.111 After World War I kerosene was urgently needed to soak wooden objects from the tropics, which were stored at the facilities in Berlin–Dahlem. However, due to a bottleneck in supply, it took more than one year until 50 L of kerosene could be delivered.112
107
Beiju is a small cake made of manioc- or tapioca flour. After contact with water the flour may ferment. Source: http://de.wikipedia.org/wiki/Beijú Online at the internet [state July-11-2006].
108
VON DEN STEINEN 1894, 1 and 134, KOCH-GRÜNBERG 2004, 199 and 473.
109
KRAUS 2004, 171.
110
FOY 1908.
111
VON LUSCHAN 1904 and 1906.
112
GRÜNWEDEL 1920.
35
The most extensive information and documentation is provided by the manual of RATHGEN (1898 and 1924), founder of the Rathgen-Forschungslabor (RFL) (see Fig. 7–9 see pp. 36-37).113
Figure 7: Person at the desk of the conservation laboratory of the State Museums in Berlin, c. 1920
Figure 8: Staff in the conservation laboratory of the State Museums in Berlin, c. 1920
113
RATHGEN 1898 and 1924.
36
Figure 9: View into the conservation laboratory of the State Museums in Berlin, c. 1920
37
This first guideline for conservation and pest control was directed towards the daily work in all museum collections of the former Königliche Museen zu Berlin as well as the former Königliches Völkerkundemuseum zu Berlin and was seen as a standard work. It was indeed a monumental achievement. Table 7 gives an overview of recommended substances for pest control, their use on various organic materials and the advisable procedures. Table 7: Recommended substances and chemicals for use on organic materials against pests provided by F. Rathgen 1898 and 1924. Substances
Physical Properties
Procedures
arsenic-soap benzene benzine campher carbon disulfide
solid gaseous gaseous solid gaseous
fumigation fumigation scattered fumigation
chloroformates crude benzene crushed pepper crushed pepper mixed with powdry alum cyanoformates/-acetates Eulan solution Globol (PDB) hydrocyanic acid kerosene
gaseous gaseous solid solid, gaseous gaseous liquid solid gaseous liquid
naphthalene
solid
fumigation fumigation scattered scattered, fumigation fumigation dipping scattered fumigation dropping, soaking scattered
potassium arsenate, aqueous solution sodium arsenate, aqueous solution mercury(II)-chloride (sublimate), alcoholic solution mercury(II)-chloride (sublimate), aqueous solution α-Tetralon (3,4-Dihydro1(2H)-naphthalinon) tetrachloromethane Zapon or Zellon mixed with poppy-seed oil
liquid
dropping
dry heat: 60-70°C
liquid liquid
solid gaseous liquid
Materials fur, fresh grain, nuts, seeds, wood grain, nuts, seeds, wood woolen tissues fur, leather, horn, paper, papyrus, rope, bast woolen tissues grain, nuts, seeds, wood feathers feathers woolen woolen woolen woolen tusk
tissues tissues tissues tissues
feathers, hair, tissue, grain, nuts, seeds, wood grain, nuts, seeds, wood fur, old
dipping
feathers, hair, tissue
spray
feathers
scattered, fumigation fumigation dipping
grain, nuts, seeds, wood grain, nuts, seeds, wood grain, nuts, seeds, wood fur, leather, grain, nuts seeds, wood, woolen tissues
38
Although there is no clear description of the differences between the effect of miscellaneous substances and chemicals, RATHGEN does assign a preventive effect to camphor (see Fig. 10), naphthalene, Globol (PDB), α-Tetralon (3,4-Dihydro1(2H)-naphthalinon) and other organic chlorine derivates.114
Figure 10: Person sprinkles camphor over a mummy at the Museum für Völkerkunde Berlin
114
RATHGEN 1924, 155 - 156.
39
It is interesting to note that potassium arsenate solution, which is included in Fowler’s solution and was available readymade in Rathgen’s time, is even found in his list.115 He recommends this substance for wood, grains, seeds and nuts. In general, the purchase and availability of chemical substances seemed to be the determining aspects in solving problems against pests. Furthermore, tetrachloromethane, benzene and gasoline were fumigated in boxes and, if available, carbon disulfide was placed in the tray(s) of a disinfection apparatus (see Fig. 11 p. 41).116 Also heating items in a warming cabinet was already practiced.117 Due to the toxicity of some substances, RATHGEN advises caution in handling them and also labels on treated items.118 Likewise he questions whether or not naphthalene and crushed pepper, mixed or not mixed with powdery alum, would prevent insects from damaging museum collections.119
115
Fowler’s solution contains 1 % potassium arsenate solution and was discovered by Thomas Fowler (1736-1801), after FALBE 1995, 1434 and 2126.
116
ibid. 142 - 145.
117
ibid. 160.
118
ibid. 163.
119
RATHGEN 1898, 131 - 132.
40
Figure 11: Disinfection shelf of apparatus of the Rautenstrauch-Joest Museum in Köln from the early 20th century used as model for a similar apparatus at the Königliches Völkerkundemuseum zu Berlin
41
5.1.3 Preparations employed during World War II To understand the specific circumstances in Berlin during World War II, here a brief historical overview should serve to elucidate the situation. Registration of all collections started as early as 1934 in order to pack and transport them in the case of war.120 Than, starting in 1941, several transports brought crates of items to various places inside and outside of Berlin.121 From 1946 onwards c. 45,000 objects were confiscated as war booty by the Red Army of the former Soviet Union and taken to Leningrad (today Saint Petersburg).122 Later in 1975 they were transferred from there to the Grassi-Museum in Leipzig, the former German Democratic Republic (see Fig. 12).
Figure 12: Crates from the Museum für Völkerkunde Berlin in storage in an exhibition hall at the Museum für Völkerkunde in Leipzig.
120
HÖPFNER 1992, 157.
121
ibid. 158 – 159.
122
ibid. 160.
42
Nearly half of the entire collection, which at that time comprised c. 175,000 objects, was transported by the Allied Forces to the so-called “Kunstgutlager” in the castle in Celle, West Germany, which was declared as the Zonal Fine Arts Repository (see Figs. 13–14). In view of the times and the circumstances, it is hardly imaginable that any serious thought was given to using pesticides, regularly or not, during the War. DITTMAR gave an alarming report on August 8, 1946: “In some crates infestation with moths had progressed to such an extent, that a seething mass of moth larvae had already completely destroyed items of great value.”123
Figure 13: Crates from the Museum für Völkerkunde Berlin in storage in the cellar Schloß Celle
Figure 14: Poster in front of the Schloß Celle to keep visitors off the grounds
123
HARTMANN 1955b, 240, translated by the author.
43
5.1.4 Preparations employed after World War II until the late 20th century Although not a gapless record, there is nevertheless some documentation concerning the application of pesticides on war booty by the Allied Forces in the Fine Arts Repository in Celle as well as in East Germany after World War II. PDB, naphthalene, hexachloroethane, DDT (preparation flit), mainly γ-hexachlorocyclohexane (preparation Jacutin) and tetrachloroethylene (preparation Illo-Gas) were applied regularly to the goods stored in the Repository in Celle between the years 1946 to 1956. Rooms were vaporized with a dosage of 30-40 Jacutin tablets recommended for 72 m3.124 Closed crates were sprayed, and moth powder was scattered in open boxes and on objects directly.125 In practice these pesticides were used by the barrel and renewed constantly.126/127 With the help of the Berlin airlift repatriation of this war booty began in 1956 and ended in 1958.128 Storage conditions prevailing for the war booty carried off to the East are scarcely recorded. As an exception FÖLBER reports during the return of the missing objects in 1990-1992, that objects were wiped with brushes soaked in turpentine before they were put in crates to be transferred to Leipzig in 1977.129 Upon arrival at their new location, the objects made of fur, wool or feathers, etc. were taken out of the crates and sprayed with lindane, polychlorocamphen or permethrin (preparation TexylSpray). After the items were aired, they were packed again in crates, which were wrapped outside with paper. Treatment was also carried out yearly between 1980 and 1989 in an exhibition hall in Leipzig, where the Berlin war booty was stored. Dichlorvos (preparation Fekama-Dichlorvos 50) was sprayed throughout the entire area, which was hermetically closed for three days to allow the fumes to penetrate.130
124
HARTMANN 1955a, 23.
125
ibid. 22-24.
126
KOCH 1973, 380.
127
AUGUSTAT 2003, no page number.
128
KOCH 1973, 382.
129
Personal comment kindly provided by Barbara Fölber, chief conservator at the Grassi-Museum in Leipzig, 1999.
130
Personal comment kindly provided by Barbara Fölber, chief conservator, and Christl Treumer, curator, at the Grassi-Museum in Leipzig, May 6, 1999.
44
Besides the circumstances due to the War, the consequences of progressive developments in natural sciences were crucial for the SMB in West Germany and consequently for the EM. A variety of pesticides with different properties of substances was created by chemical industry to prevent the infestation by pests and also against acute attacks. RIEDERER regards damages by pests as the most serious problem for museum collections and presents the latest state of knowledge in science on conservation concerning pest control in his guideline.131/132 There, the basis for conserving paper, parchment, leather, wood and tissues is offered to the EM as well as other museums.133 Table 8 (see p. 47) shows the chemical substances, their properties and their procedures that are used against pests and on materials. Between the early 1960s and late 1999s in addition to these available substances (see Table 8), basic treatments were carried out at the EM regularly with camphor, spread on shelves in all storage areas (see Fig. 15).
Figure 15: Old can of oily camphor used in a cabinet against pests
131
RIEDERER 1977, 24 – 25.
132
Translation by the author: art and chemistry – preserving the irrecoverable
133
ibid. 50 – 68.
45
Treatments with gas consisting of tetrachloroethylene, which was available in the preparation Illo-Gas, were conducted with the disinfection apparatus belonging to the Museum (see Fig. 16).134
Figure 16: Employee in the Museum für Völkerkunde Berlin places objects on the disinfection shelf of apparatus
134
Personal comment kindly provided by Klaus Scharn, chief conservator at the EM from 1985 until 1999, September 30, 2004.
46
Table 8: Chemical substances and their use on materials provided by Josef Riederer Active Substance
Physical Properties
Procedures Materials
2-phenylphenol (solutions of)
liquid
vapor delivery
butylamin
liquid
Carbon bisulfide
carbon disulfide
liquid
vapor delivery
paper, parchment
DDT
dichloro-diphenyltrichloroethane
white crystals or powder
scattered
textiles, wood, paper, parchment
E 605
parathion
liquid, powder
scattered
paper, parchment
Etox
ethylene oxide
gaseous
gaseous delivery
Eulan
sulfonamides
liquid
paper, parchment textiles
Haltox
bromomethane
gaseous
gaseous delivery
wood, paper, parchment
hydrocyanic gas, prussic acid
hydrogen cyanide
liquid
vapor delivery
leather, wood, textiles, paper, parchment
Impra-HGF
lindane
liquid
dropping
wood
lindane
γ-hexachlorocyclohexane
powder
vapor delivery
paper, parchment
naphthalene
white crystals
vapor delivery
textiles
Paral
dichlorvos
liquid
vapor delivery
paper
PCP
pentachlorophenol
crystals
vapor delivery
wood, textiles
pentachlorophenollaurate
white crystals
1,4-dichlorobenzene
crystals, mothballs
vapor delivery
pyrethrum
powder
vapor delivery
thymol
white crystals
vapor delivery
textiles
Vikane
sulfuryl difluoride
gas
gaseous delivery
paper, parchment, wood
Xyladecor
several biocides
liquid
apply with brush
wood
Xylamon
several biocides
liquid
apply with brush
wood
Zyklon B
hydrogen cyanide
liquid
gaseous delivery
paper
Trade Name
PDB
textiles paper, parchment
textiles textiles, paper, parchment paper, parchment
47
5.1.5 Current use of preparations and procedures The standard of the disinfection apparatus was technically renewed in 1994 and remained in use until the beginning of 2004.135 Then a nitrogen fumigation bubble was installed (see Fig. 17). When in process, oxygen content of the indoor air inside the bubble is reduced to
