Summary of paper by Josée Van Loon National seminar held in Ghent 21 st October, 1995 Health and toxicological aspects of the Restoration of Art Objects Organised by Art Restorers Association, Belgium ISBN 90-802791-1-0; page 68-75 Left pannel: painting of Paracelsus (1493-1541), the father of today's pharmacology and toxicology

1. WHY A SEMINAR ON THE PROTECTION OF ART RESTORERS?

These elements were the subject of an idea born within the Central Board of Art Restorers Association Belgium at one of its monthly meetings in Antwerp in the autumn of the year 1994. The board concluded that till now, most of its attention was drawn to the expertise of the restoration and conservation work. Its major concern is focused on the Art object and this is reflected by its permanent interest in the professional training programme of the Restorers. The following up and the permanent study of new restoration techniques by its individual members has been focused mainly on the protection of the Historic value of the Art Object. Therefore the members of this Association are gathering frequently in workshops and read specialised professional literature. The organisation of their workshop is directly related to the Art Object.

Some of us claimed that apart from the basic knowledge of the restorer, history on the one hand and chemistry on the other hand, which is basically so necessary for a good training in restoration, in most education programmes only a minimum of attention is paid for the health aspects of this beautiful profession. One of the reasons is that restoration in general is such a big field and that the circumstances in which Restorers work can be extremely different. In this way Art Restorers Association Belgium decided that we should try to organise a multidisciplinary meeting around the toxicological and health aspects of restoration of Art works.

At first, we wanted to include some general informative knowledge of toxicology. Secondly, the discussion between toxicologists, pathologists and Restorers and the chemical industry covering different disciplines in restoration, should be highlighted. We discussed the training of the Restorers in Belgium with all its gaps, the lack of official recognition of the profession and title, etc... A list of the most currently used chemical compounds was established. The name and the concept of the seminar were born and the time was ripe to start with the programme.

Very rapidly new enthusiastic colleagues from Belgium and the Netherlands joined us with the idea and stimulated us to continue to work on it and finally an organising committee was established. It was decided that the centrifugal force of this Meeting should be the discussion of the most important health aspects of restoration of Art Objects with the 'accent' on discussion.

Therefore, well known experts were selected. We contacted Willy Lambert (Toxicologist) and Léopold de Thibault (Physician, occupational health) from the University of Ghent Belgium and started the whole discussion of Antwerp again in my workshop in Ghent. Keeping in mind that a good discussion is based on an exact knowledge of chemistry, physiology and pathology we also needed a Pathologist. Therefore An Vynckier from Janssen Research Foundation was selected. Marcel De Cleene, the Science Information Officer of the University of Ghent was nominated as the 'rapporteur' and the 'moderator' of this seminar.

And the Restorers...? They will participate from the floor. We trust in their interest and enthusiasm to conduct a fruitful debate. We are convinced that they will induce some controversial idea's and present problems which are not easy to resolve. At the end of September, when I lay the last hand on this booklet we have got about 80 subscriptions of restorers of all kind of disciplines: furniture, paintings, paper, books, leather, monuments, textile, metal, wood, ... I am very glad to have support from restorers from the Netherlands. The exact number of participants will be known on the day of the seminar. In the coming days I expect several new subscriptions for the seminar, especially from the students of Art Schools who start their classes in October.

At the seminar only one man will be lacking: Paracelsus, the father of modern toxicology...

2. THE DOSE MAKES THE POISON

Paracelsus (1493-1541) is considered as one of the founding fathers of toxicology and pharmacology. He was the person who claimed that 'All things are poisons, for there is nothing without poisonous qualities. It is only the dose which makes a thing a poison'. Consequently toxicology can be defined as the study of the adverse or toxic effects of chemical and physical (so called noxious) agents on several or all biological systems. It is an integral component of risk assessment which uses the data obtained from toxicological studies (experimental and epidemiological).

In literature I could learn that toxicology is considered both an Art and a Science. The Science involves the data-gathering phase while the Art of toxicology uses these acquired data to predict the likelihood of adverse responses in humans following exposure to one or more agents in situations where there is limited information. For example, exposure of mice to chloroform can produce liver tumours. This is a well known phenomenon. The conclusion that it could do so in man is however, an unsure prediction or hypothesis which has to be demonstrated.

Personally I think that the last statement forces us to be alert and to be interested permanently in the toxicological aspects of our profession. If not we will be considered as individuals which will be used in statistical analyses of epidemiological studies. As far as I am concerned I am not interested to be such an individual.

For the restorer one thing is already clear: we have to reduce the daily exposure to these noxious agents as much as possible. According to Paracelsus many chemicals and physical particles can cause adverse reactions to the restorers body tissues. The total daily exposure (total dose effect) is very important. From this simple statement we can learn that storing chemical products in a separate and special room with ventilation system (hoods), in special and small containers with appropriate closing systems away from the workshop, can protect us considerably. This is especially the case for volatile compounds. Thus, only bring it in your Workshop when you need it.

Also order only minimum amounts. Most providers will deliver chemicals within 24 hours. There is no need to buy 10 times more than you need. I know that one will offer you discounts when ordering big amounts but in my opinion this is not necessary and a fallacy used by some dealers. Providers can store these compounds more adequately than we can. And, remember, even if you have to pay more to purchase low amounts,... consider this as a contribution for your health insurance.

Finally, ask for the technical note and safety release of the product. It is necessary that you know exactly which compound you are working with. If you know what it is you can estimate if it is toxic or not and if you have to take special precautions. As an example, I refused to try a product which I could obtain for free from a company for the de-acidification of wood pulp paper. I was told that the composition was kept secret for commercial business. Also this is a fallacy, and I gratulated the firm for its kind offer.

During the seminar and when reading this booklet we will learn a lot of toxicity and protection when using chemical compounds. I don't want to come back on this topic. Therefore others in this seminar are much more qualified than I am.

Today, it is not realistic to believe that we could work without chemical compounds. Most important is that you think before you start with a treatment. In some cases chemicals are used when it isn't really necessary. The conclusion is simple. Before an intervention with chemical compounds look for the right treatment in favour of both: for the Art Object and for yourself. Look into literature and look eventually for good alternatives. For example; during years I could see that some very good book binders added formaldehyde to the starch for better conservation of the glue. It has no sense to do that and it is even not good for the paper. It is simple, make your glue fresh and prepare only limited volumes.

Ask for advise if there is some doubt and now we come to the key of the problem.

Accurate prediction of the potential risk of a substance requires expertise in chemistry, physics, immunology, pathology, physiology, biochemistry, embryology, public health, epidemiology and risk assessment. It is clear that only the toxicologist is able to cover all these aspects. However many of the problems require an integrative approach of problem solving and to my best knowledge only a few of them are interested in the behaviour of the restorer in his workshop and restoration techniques. Professional restoration of Art Objects necessitate knowledge of history of Art, old specific techniques related to the object, accurate restoration techniques, chemistry, biology, etc...

Consequently, at the end of this century, due to the dramatic increase in knowledge in general, there are restorers and toxicologists and today nobody is capable to cover both aspects. Cooperation seems to be necessary and I am very grateful for the comment of Marcel De Cleene, 'rapporteur of the seminar'. Let us create a permanent multidisciplinary forum with international contacts where we can gather and exchange ideas. I am sure that within Art Restorers Association Belgium there will be some interest.

3. WHAT ABOUT THE OCCASIONAL NON PROFESSIONAL RESTORER?

Professional restorers are grouped in associations. Art Restorer Association is a typical example. One of the tasks of such an Association is to disseminate scientific and good information and to be involved in permanent education of its members. This seminar is only one example of its dynamism. Members also receive information via a review named 'Contact' in which for example scientific and technical information about chemical compounds used in restoration and written by specialists is disseminated. Also bilateral exchange of ideas, resources and material with other comparable associations is, according to this Association, a necessity. Consequently, on a professional level we are quite good organised.

But what about the 'occasional non professional' restorer. In many countries (such as in Belgium) there is no governmental implementation on the definition of restorer. The profession of restorer is not officially recognised and many individuals can promote themselves as 'restorer'. This is a problem for both the 'Art Object' and the 'individual'. Following example has to make things clear.

Methylene chloride is the principal active ingredient in organic-based paint strippers, accounting for approximately 35 percent of all United States methylene chloride production in 1992. It is used in both consumer and industrial paint removers.

To my best knowledge, and from the information I received from some of my colleagues, methylene chloride is not used by professional restorers. In contrast it is frequently used by the occasional restorer; by those who found a nice but painted piece of old furniture on the garret of their grandmother. Others also use it more frequently because they trade furniture from the beginning of this century of which they remove the paint and the varnish.

The highly volatile methylene chloride is released into the atmosphere from industrial and consumer uses. Humans acutely exposed to methylene chloride experience adverse effects of the central nervous system and the heart. There is inadequate evidence of carcinogenicity of methylene chloride in humans, in contrast, there is sufficient evidence of its carcinogenicity in animals. There is no information on the developmental toxicity or reproductive system effects of methylene chloride in humans.

It is clear that the use of such products should be limited and restricted to professionals.

4. FIELDS OF TOXICOLOGY TO EXPLAIN RISK ASSESSMENT

Complementary to the summing up of safety assessments (risk assessment and risk management), the toxicologist needs a comprehensive picture of the risk associated with the use of one specific drug or a combination of several different drugs. When he deals with the risk of the use of certain compounds he will always rely on following fields:

Biochemical Toxicology uses the methods of cellular physiology to determine how toxic substances adversely affect the normal function of cellular components. How a substance inhibit an enzyme activity which is essential for normal cell function is for example a very important question.

Molecular toxicology involves the use of molecular biology to investigate the effect of toxic substances at the level of DNA. Molecular biology techniques have been used to examine the effects of compounds on gene regulation and DNA mutagenesis.

Chemical carcinogenesis investigates how compounds initiate and promote the development of cancer. Compounds that have been investigated include polycyclic aromatic hydrocarbons, aromatic amines, halogenated hydrocarbons and mycotoxins.

Genetic toxicology is the study of the interaction of chemical and physical agents with the process of heredity. These studies involve investigating the type of mutations that an agent causes and its effects on chromosomes.

Developmental toxicology is concerned with the investigation of chemically induced teratogenic effects or birth defects.

Immunotoxicology examines the effect of substances on the immune system. Studies involve examining the ability of chemicals to compromise immune function, elicit for example hypersensitive reactions.

Reproductive Toxicology The effects of drugs and environmental chemicals on reproductive fitness is a major health concern. Reproductive toxicologists examine how toxic substances affect reproductive capacity and develop assays to identify agents that may adversely affect reproductive performance.

During the seminar several aspects of the use of chemical compounds used in a restoration workshop will be treated in the light of the above listed fields.

5. TOXICOLOGY DATA NETWORK AND INTERNET

For those who have access to internet and who have knowledge of chemistry and toxicology, there is TOXNET® (TOXicology Data NETwork). This is a computerised system of files oriented to toxicology and related areas. It is managed by NLM's Toxicology Information Program and runs on a series of micro-computers in a networked client/server architecture. TOXNET is an integrated system containing modules for building and reviewing records as well as providing sophisticated search and retrieval features for NLM on-line users.

TOXNET was designed to be user-friendly. Built into the system is a high degree of flexibility in search, print, and other commands. Users can easily extract data on known chemicals or identify unknown chemicals based upon their characteristics, through free text searching. A wide variety of on-line user assistance is available.

TOXNET is available 24 hours a day, seven days a week. Registered NLM on-line services users can access these files by direct dial or through the TYMNET, SPRINTNET, or COMPUSERVE telecommunication networks. TOXNET is also available to registered users via INTERNET at the following address: medlars.nlm.nih.gov/ . All TOXNET files are also accessible via the GRATEFUL MED Software. User-friendly menu searching built into Grateful Med is available for several of these files. For more information on Grateful Med, contact the MEDLARS® Management Section (see next chapter).

For detailed information on TOXNET contact: Specialised Information Services, National Library of Medicine, 8600 Rockville Pike, Bethesda, MD 20894, Telephone from Belgium: 00-1-301 -496-6531, E-mail: toxmail@nlm.nih.gov

EXTOXNET - EXtension TOXicology NETwork is a cooperative effort of University of California-Davis, Oregon State University, Michigan State University, and Cornell University. Primary files are maintained and archived at Oregon State University. They have a page which allows searching and browsing of the entire EXTOXNET InfoBase - select for details. I highly recommend this site (it is free). If you want details about a product, see URL, http://ace.orst.edu/info/extoxnet/ghindex.html

6. CONCLUSION

In most restoration workshops there are 3 types of noxious agents that can have adverse effects on the restorer's health;

1. Chemical agents (synthetic or naturally-occurring) that include: typical compounds used by restorers, household products, substances produced by bacteria, fungi, moulds, spores, plants and animals.

2. Physical agents such as radiation: UV-light, electromagnetic waves, laser beam light.

3. Physical agents such as noise, pressure and dust.

Initially , and due to our enthusiasm, we intended to cover al these aspects in the seminar but very rapidly we could learn that this was an impossible mission and that we should need several days and speakers to reach our goal. We concluded therefore that we should better concentrate on some of the commonly used chemical compounds in the restoration workshop.

Consequently, all aspects of toxicity indirectly or directly induced by bacteria, fungi, moulds, spores, plants and animals (parasites) as well as the influence of UV-light, electromagnetic waves, laser beam light will not be treated in this seminar. This is another challenge for the future.

This seminar does not try to resolve the problems on the toxicological aspects of our profession but it certainly will provide new impulses for a more structured forum where new initiatives and possibly new ideas in the field of the use of chemical compounds in the restoration workshop, can be developed. Such a forum has to be open and without any threshold. This will be in favour of both, the Art Object and the restorer.

A professional restorer has a correct attitude towards the Art object, the human and humanity. Therefore the danger resulting from the use of certain chemicals and materials has to be estimated in the right way; under- nor over-estimation are necessary. Therefore knowledge and vigilance are wanted. Let us enlarge the Science and the Art of Paracelsus with the watchfulness of a Persian soldier,...

7. ACKNOWLEDGEMENTS

I remember how enthusiastic people were and still are at the moment. Many people have collaborated with details. It is impossible to name them all. Many of them prepared, organised and worked voluntarily in silence. Some of them didn't want to be mentioned by name. With this I would like to thank everybody, co-workers, contributors, delegates and the sponsors of the seminar. I will acknowledge them personally at the seminar. Editing a book is not an easy task, especially around a topic which is not directly our field but in which we have to be interested. Furthermore the 'restoration world' seems to be an immense field with very variable application of chemicals and techniques. This multidisciplinary forum is challenging but very complicated at the same time to discus at the same level. A lot of advise is needed.

This book is dedicated to those who gave me continuous advise and help and stimulated me to continue with this seminar. More especially I want to thank my teachers: M. Wooton & T. Albro from Library of Congress and F. Mowery from the Folgers (Washington-USA) and last but not least J. Puissant from Centro del bel Libro (Ascona-Switzerland) from whom I could learn a lot. They always draw my attention to work carefully with chemical and physical agents and to be permanently interested in the basics of chemistry and toxicology which is a part of a good education in restoration. Also thanks to my husband who likes to teach me physiology and biochemistry. It was for me a great experience to create new friendships and keeping only one idea, the good work.

8. REFERENCES

Budavari, S., O'Neil M.J., Smith, A. & Heckelman P.E. (1989) The Merck Index, 11th ed. Merck & Co., Inc., Rahway, N.J.

Clydesdale A. (1990) Chemicals in conservation: a guide to possible hazards and safe use. Second edition. Scottisch Society for Conservation and restoration, SSCR.

Masschelein-Kleiner, L. (1993) Oplosmiddelen en de gevaren voor kunstwerk en restauratoren. Centraal laboratorium voor onderzoek van Voorwerpen van Kunst en Wetenschap, 13, 1 -21.

Mannsville (1993) Chemical Products Synopsis, Methylene Chloride. Mannsville Chemical Products Corporation, January.

McCann, M., Ph.D., C.I.H. (1992) Artist beware, the hazards and precautions in working with art and craft materials. Second edition. Ed. Lyons Burford, New York (ISBN: 1-55821-175-6).

(Methylchloroform (1,1,1-Trichloroethane) Chemical Summary URL, http://www.epa.gov/docs/chemfact/chemical/s_dcm.txt.html (meanwhile URL has changed)

TOXICOLOGY DATA NETWORK URL, http://www.nlm.nih.gov/factsheets.dir/toxnet.html (meanwhile URL has changed)

(*) EXTOXNET - EXtension TOXicology NETwork is a cooperative effort of University of California-Davis, Oregon State University, Michigan State University, and Cornell University.