Kortlægning af kemiske stoffer i forbrugerprodukter, 64 – Afgivelse af kemiske stoffer fra produkter af eksotisk træ

Afgivelse af kemiske stoffer fra produkter af eksotisk træ

Summary and conclusions

The purpose of this project is to analyse the emission of chemical compounds and to determine whether there are health risks connected with consumer products made of exotic wood when used in the home.

The main stress has been laid on the emission of volatile chemical compounds to the indoor air and to a less extent to the constituents and compounds emitted from the products by migration into artificial saliva. The emitted compounds have been assessed in relation to LCI values and indoor-relevant time-values. It was also assessed, whether the examined wood species can cause allergic reactions.

It should be remarked that the results presented in the report solely concerns the products examined, the results should, therefore, be considered as being based on random sampling. The results are thus not representative of the respective wood species or for exotic wood in its entirety.

The experimental part includes an examination of 10 selected products made of exotic wood. The products partly represent the product groups, which have been found on the market, and partly, wood species, which are widely used for these product groups. The 10 products have been listed in Table 1.

Table 1 Selected Products

Specimen no.	Wood species	Botanical name	Product	Surface treatment, if any
1	Rubber wood	Hevea brasiliensis	Dining table	Lacquer**
2	Ramin	Gonystylus bankanus	Venetian blind	Stain
3	Sheesham	Dalbergia latifolia	Bed table	Wax
4	Teak	Tectona grandis	Tray
5	Jatoba	Hymenaea courbaril	Floor	Oil
6	Merbau	Intsia bijuga	Floor	Oil
7	Khaya mahogany	Khaya ivorensis	Kitchen tabletop	Oil *
8	Iroko	Chlorophora excelsa	Kitchen tabletop	Oil *
9	Cherry wood, American	Prunus serutina	Kitchen tabletop	Oil *
10	Belalu	Albiz(z)ia falcata	Figure	Ink

* The products, which normally are oil treated, but which in this examination form part as untreated

** The distributor informs that this product is wax treated. It has been evaluated to be lacquered

The products have what regards the majority been examined with the surface treatment, which normally appear with the consumer. What regards oil treated products, products have been bought – when possible – without oil treatment. This does not represent a typical situation of use, but it does, however, give a better picture of which chemical compounds are emitted from the wood itself. Notoriously, oil treatment emits a number of compounds, which might mask the emission from the wood itself.

On basis of the results from the initial qualitative screening of the emission from the 10 products, 5 products were chosen for a further quantitative analysis of the emission in climate chamber. The selection of the 5 products was based on the following criteria:

Products, which are used on the largest surfaces
Products, which emit the most
Products, which are mostly used
The type of the emission from the product

The 5 products are listed in Table 2.

Table 2 Products selected for quantitative analysis of emissions

Specimen no.	Wood species	Botanical name	Product	Surface treatment
1	Rubber wood	Hevea brasiliensis	Dining table	Lacquer
2	Ramin	Gonystylus bankanus	Venetian blind	Stain
3	Sheesham	Dalbergia latifolia	Bed table	Wax
6	Merbau	Intsia bijuga	Floor	Oil
8	Iroko	Chlorophora excelsa	Kitchen tabletop

Only minor amounts of chemical compounds were found in the examined products of exotic wood (with and without surface treatment) by the climate chamber measurements.

Totally 25 individual compounds were demonstrated by the climate chamber measurements, out of which more of the individual compounds could be retrieved in a lot of the products. A part of these compounds origins predominantly from the surface treatments of the products in question.

The assessment of possible comfort and health effects from emission of compounds from products made of exotic wood includes exposure via inhalation, contact and migration into artificial saliva. The assessment is based on toxicological principles and literature data. At assessment a scenario from a home forms the basis.

The impact of exotic wood products on the indoor climate was partly assessed by an S-value, which is a sum of concentrations in the indoor climate divided by the "lowest concentration of interest for the indoor climate" (LCI), and partly by an indoor-relevant time-value based on odour and irritation thresholds.

The lower the S-value the more acceptable the emission from the exotic wood and/or its surface treatment. For S-values below 1 no harmful health effects are expected.

The measurements stated draw a picture indicating that emission of individual compounds only to a very limited extent takes place from the examined exotic wood species or their surface treatments. None of the products will at the stated emission concentrations cause health problems.

Rubber wood is the only product among the examined ones, which has an S-value that in the measuring period exceeds 1. The individual compounds important in relation to the calculated S-value are formaldehyde and acrolein. It is deemed less likely that they are constituents of the rubber wood itself. There is on the contrary every probability that they origin from the surface treatment.

Products made of rubber wood and belalu were subjected to an analysis for the emission of chemical compounds by migration into artificial saliva. The analyses showed that none of the compounds emitted by migration form part in concentrations, which exceed the calculated TDI-values (Tolerable Daily Intake). However, compounds occur in both the examined products, which have been entered on the list of The Danish Working Environment Service of allergy or hypersensitivity causing compounds in the working environment – including vanillin and anhydride of phtal acid. The emitted compounds origin most probably from the surface treatment. The problem is of course of greatest importance in case the products are used for storage of food (salad bowls, chopping boards, kitchen tables etc.) or if they are used for purposes, where they will get into close contact with the skin for a long time e.g. musical instruments and trinkets.

As rubber wood degrades very fast, this wood species is always treated with fungicide. Samples of the rubber wood were, therefore, subjected to analyses to demonstrate residues of active substances (including numerous elements). The analyses demonstrated content of boron, which indicates that the rubber wood has been treated with a boron containing fungicide. Taking the content of boron into consideration it would be inadvisable to use Hevea brasiliensis without surface treatment, in case the wood has been treated with a boron containing fungicide.

On basis of the examined consumer products of exotic wood forming part of the project, the following can be concluded:

LCI-values laid down for emitted compounds are predominantly based on irritation and only in individual cases on the health effects of the compounds.

The products (with and without surface treatment) of the wood species Ramin, Sheesham, Merbau and Iroko emit only to a limited extent substances to the indoor air. The indoor-relevant time-value is for all these products less than 3 days. S-values are less or equal to 0.2.

The product of rubber wood (with surface treatment) was the examined product, which has the most extensive emission. The indoor-relevant time-value for the product is higher than 28 days and the S-value is 0.6 (after 28 days).

The surface treatment of the examined product is not suitable for products in contact with food due to the emission of chemical compounds by migration into artificial saliva.

The content of boron in the wood of the product examined is so high that it cannot be recommended that the product be used without surface treatment.

Among the 5 examined wood species Ramin should be considered to be more irritating to the skin and airways than the other 4 wood species. Allergic reactions in the airways can be seen by inhalation of dust from Iroko and Ramin. Allergic contact dermatitis can, especially, be seen from Iroko and Sheesham and, presumably, to a lesser extent from Ramin. Some of the contact allergens have been identified, i.e. chloroforin, R- and S-4 methoxydalbergione and 1,4 quinone latinone.

With the proviso that we have only examined one product of rubber wood, the products made of this wood species do not seem to present risks for persons, who are allergic to natural rubber latex.