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Emission of chemical substances from products made of exotic wood

5 Results

• 5.1 Qualitative Screening
• 5.2 Quantitative Climate Chamber Measurement
• 5.3 Determination of Content of Natural Rubber Latex Allergens in Rubber tree
• 5.4 Determination of Content of Fungicide in Rubber tree
• 5.5 Analysis for Migration into artificial saliva
• 5.6 Results from Literature Survey
  • 5.6.1 Allergic Respiratory Symptoms and Allergic General Reactions
  • 5.6.2 Allergic Skin Symptoms

Results of the qualitative screenings are stated overall in paragraph 5.1 and results in detail in Appendix C. Results of the quantitative climate chamber measurements are stated over all in paragraph 5.2 and results in detail in Appendices D and E.

In consideration of the health and comfort assessments, concentrations measured in climate chamber were converted to concentrations, to which persons are exposed in the indoor air in a typical room scenario.

The measured emissions can not be considered as covering for the examined type of material or as generally representative of emissions from exotic wood, but can be used as an indication of the emission from the examined types of products. The actual measurement results are exclusively valid for the analysed products.

5.1 Qualitative Screening

By the initial screening by headspace-analysis of the 10 selected products 74 different chemical compounds were identified cf. the result tables, Appendix C. In Table 15 the total amount of emitted compounds from the individual compounds and their mutual order of priority (stated according to total amount – 10 states the largest total amount) are stated.

Table 15 Total amount of emitted compounds by headspace

If the only total amount of the emitted compounds by headspace is considered, it appears that the surface treated wood species merbau and rubber tree emit the largest amount of chemical compounds.

The compounds emitting from the individual products are listed in Table 16. The CAS no. of the compounds and their classification are stated in Appendix C.

Table 16 Emitted compounds by headspace-analyse

5.2 Quantitative Climate Chamber Measurement

Out of the 10 selected products from headspace, 5 were selected for climate chamber measurement. By the quantitative climate chamber measurements of the emissions from the 5 products, 25 different chemical compounds were quantified. The emission from the individual products is stated in Table 17. The concentrations of the compounds, CAS no. and their classification is stated in Appendices D and E.

The most important compounds are distributed in the products examined as stated in tables 22-26 in paragraph 6.1.

Table 17 Distribution of the emitted compounds in climate chamber

Except for iroko, specimen no. 8, all specimens are surface treated with wax, stain, oil or lacquer.

Very low indoor-relevant concentrations were found for ramin, sheesham, merbau and iroko. The emissions origin primarily from the surface treatment and include mainly alcohols and glycolethers and –esters. For iroko, which was not surface treated, the emission origins from the wood itself.

The emissions from rubber tree origins primarily from the lacquer and include mainly aldehydes, aromatic hydrocarbons, alcohols and glycolethers and –esters.

5.3 Determination of Content of Natural Rubber Latex Allergens in Rubber tree

Analysis of the content of natural rubber latex allergens in three specimens sampled from three different staves of the tabletop of test specimen no. 1 was carried out. The specimens were sampled in the wood itself, i.e. without surface treatment. Analysis was carried out for the proteins Hev b 1, Hev b 3, Hev b 5 and Hev b 6.02.

No content of proteins was traced in the three samples.

5.4 Determination of Content of Fungicide in Rubber tree

5.4.1.1 Organic Components

Results of analyses for content of organic active ingredients: Tebuconazole, propiconazole, tolylfluanid, dichlofluanid, IPBC (3-iodo-2-propynyl-butyl-carbamat) and pentachlorphenol are shown in Table 18.

For none of the compounds concentrations above the detection limit could be demonstrated

Table 18 Content of organic components

5.4.1.2 Elements

Results of analyses for content of inorganic components are stated in Table 19. Content of boron, manganese and zinc were traced in the sample. The content of copper varies greatly, which indicates inhomogeneity of the test material. The copper may not origin from the wood itself, but has been added as pollution during the pulverisation of the test material.

The high content of boron indicates that the rubber tree has been treated with a boron fungicide.

Table 19 Content of elements

5.5 Analysis for Migration into artificial saliva

Results of analysis for migration into artificial saliva from lacquered tabletop made of rubber tree (Hevea brasiliensis) and ink treated figure made of belalu (Albiz(z)ia falcata) are stated in Tables 20 and 21. A complete list of the compounds found appears from Appendix F.

Table 20 Compounds migrated from lacquered tabletop (Specimen no. 1)

Table 21 Compounds migrated from ink treated figure (Specimen no. 10)

5.6 Results from Literature Survey

Due to differences in the immunological mechanisms, the allergic reactions have been evaluated for asthma and urticaria respectively (IgE-antibody-mediated), allergy and for contact eczema (cell mediated allergy) separately.

5.6.1 Allergic Respiratory Symptoms and Allergic General Reactions

5.6.1.1 Hevea Brasiliensis, Rubber tree

In the literature there is no information available about allergic respiratory symptoms caused by exposure to wood dust from Hevea brasiliensis.

There are no publications on allergic reactions caused by e.g. food, which has been in contact with items made of Hevea brasiliensis.

Latex from Hevea brasiliensis contains numerous allergen proteins, there is no information about the incidence of latex allergens in wood or wood dust.

The allergen proteins have been characterised and the major-allergens were designated Hev b 1, Hev b 3, Hev b 5, and Hev b 6.02. Between 3 and 17% of the public health staff are estimated to be sensitised that means that they could develop allergic reactions by exposure to allergen proteins from the latex sap (Turjanmaa et al., 2002).

At analysis of wood from Hevea brasiliensis no allergen proteins could be demonstrated.

5.6.1.2 Chlorophora Excelsa, Iroko Synonyms: Kambala, African teak, moreira, moule morus excelsa, swamp mahogany, rock elm

Numerous publications on respiratory symptoms, incl. allergic alveolitis exist. Potential allergen caused by allergy asthma has, however, not been identified (see paragraph 3.1).

Hausen (1981) lists 6 references, in which iroko has been described as cause of lung symptoms, may be on irritative basis, may be on allergic basis. Iroko has been stated as cause of allergic alveolitis. De Zotti (1996) has in an examination of 7 patients stated iroko as one among more cause of asthma. Azofra and Olaguibel (1989) describe a patient occupational asthma, but without documentation that allergic mechanisms are involved.

5.6.1.3 Dalbergia Latifolia, Sheesham

Synonyms: Indian rosewood, East Indian rosewood, Bombay blackwood, palissandre d'Asie, Asian rosewood.

Dalbergia is a large group of wood species coming from all over the world. Many different species have been described, which can often be difficult to separate. In addition, pao ferro (Machaerium scleroxylum) can be difficult to distinguish from dalbergia-species.

No asthma-symptoms or rhinitis seem to be described. Incidence of urticaria and Quincke-oedema quoted by e.g. Woods (1976) can be an indication of allergic reaction of type 1 caused by air borne allergens of protein character (see paragraph 3.1), there are, however, no recent descriptions of it and potential allergen has not been identified.

5.6.1.4 Gonystylus Bankanus, Ramin

Synonyms: Malawis, melawis

Hausen (1981) describes in 3 reports asthma, caused by ramin, which may be allergically caused (e.g. Howie et al., 1976). In excess a case of Hinojosa et al. (1986) is described, in which an antibody-mediated reaction seems to exist. Hausen (1981) states ramin to cause allergic alveolitis. There is, however, no published information about the identification of allergen protein in the wood dust from ramin, even though the incidence of allergic lung symptoms and contact urticaria could indicate this.

5.6.1.5 Intsia Bijuga, Merbau

Not mentioned by Hausen (1981) or Mitchell (1979).

5.6.2 Allergic Skin Symptoms

5.6.2.1 Hevea Brasiliensis, Rubber tree

There were no published information in the screened literature about contact allergic eczema or contact urticaria (see paragraph 3.1) to the wood of Hevea brasiliensis, as no contact allergens in the wood was described. Natural rubber latex products made of the sap have on the contrary caused contact eczema (Sommer et al., 2002).

In some of these cases it was an undeclared content of natural rubber latex sap of the well-known allergen accelerators etc., but allergy towards the latex sap has also been described without such hidden amounts of accelerators have been demonstrated. It is possible that real contact allergens may occur in the sap as known from other species of plants e.g. sesquiterpenes.

In most of the cases, in which contact allergy has been demonstrated towards the latex-sap, it was an IgE-mediated allergy towards natural rubber latex proteins (see above), and it was symptoms in an " intermediate phase" between type-1 and type-4 allergy, designated "protein-contact dermatitis" (Janssens et al., 1995).

In an article from 2003 the use of Glycidyl-methacrylate is described to change the timber to increase its strength (Devi et al., 2003). Glycidyl-methacrylate is as other derivates of methacrylate described as allergen (Lepoittevin and LeCoz, 2000). It is unknown, whether the described method has been used in practice.

5.6.2.2 Chlorophora Excelsa, Iroko

Synonyms: Kambala, African teak, moreira, moule, morus excelsa, swamp mahogany, rock elm.

The wood contains chlorophorin, which has shown to be a moderately strong allergen (Hausen, 1981). The allergen consists of two components, maybe isomers and only one of them is allergen. Contact urticaria has not been described.

Mitchell (1979) refers to an epidemic in Breslau in 1910 in persons, who processed the wood. In excess, Mitchell has listed 20 later publications on sensitisation. In newer literature there are more case descriptions (Hinnen et al., 1995; Stingeni et al., 1998).

5.6.2.3 Dalbergia Latifolia, Sheesham

In Dalbergia species more contact allergens are isolated, from strong to weaker allergens. Ranked in order of degressive allergenicity (Hausen, 1981): R-3,4-dimethoxydalbergion, R- and S-4-methoxydalbergion, S-4,4-dimethoxydalbergion, S-4'-hydroxy-4-methoxydalbergion.

Thus Dalbergia latifolia contains semi-strong R- and S-4-methoxydalbergion and1,4 quinone latinon (Hausen, 1981), and there are numerous publications on allergic contact eczema. Woods (1976) cites publication, in which Dalbergia latifolia is described as the cause of urticaria in cabinetmakers.

The wood has especially been used for musical instruments, and cases have been decribed of contact eczema towards the chin support of violins, the mouthpiece of flutes and handles of a knife (Hausen, 1981; Mitchell, 1979). Woods (1976) refers to a case of air borne contact eczema in a person, who lived next to a factory that processed Dalbergia latifolia. Other cases of contact eczema have likewise been described about workers processing the wood (Gallo et al., 1996).

Dalbergia nigra is described as the cause of UPPE, a very aggressive, but also of rare occurrence skin reaction probably based on allergy. There is no information that Dalbergia latifolia could cause a corresponding reaction. There is no information that Dalbergia laifolia could cause a corresponding reaction.

5.6.2.4 Gonystylus Bankanus, Ramin

Synonyms: Malawis, melawis

Both allergic contact eczema and unusually strong skin irritation have been described. Thus Mitchell (1979) and Hausen (1981) describe that the wood contains some very sharp fibres that can cause irritative inconvenience, in case that they are not removed. These fibres can also cause eye irritation. Reference is only made to isolated cases of contact urticaria, which may also be caused by the irritating sharp fibres.

Two references both report a case of air borne allergic contact eczema (Beck and Roberts, 1982; Bruynzeel and Dehaan, 1987). Hausen (1981) describes a case of eczema, in which the allergen is not safely identified, it states, however, that it may be 2,6 dimethoxy-1,4-benzoquinon. Bruynzeel and Dehaan refuse that this compound could be the cause.

Ramin is in excess mentioned to cause urticaria and eczema by both Mitchell (1979), Hausen (1981) and Woods (1976).

5.6.2.5 Intsia Bijuga, Merbau

Neither Hausen (1981) nor Mitchell (1979) mentions the wood species.

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Version 1.0 September 2005, © Danish Environmental Protection Agency