Monitoring of polycyclic aromatic hydrocarbons and water-extractable phenols in creosotes and creosote-treated woods made and procurable in Japan

Abstract

The recycling of disused railway sleepers treated with wood preservatives such as creosote as exterior wood for use in gardens has recently become popular in Japan. Creosote contains high quantities of polycyclic aromatic hydrocarbons (PAHs), and can lead to skin irritation and disease. In this work we have determined the amount of PAHs and water-extractable phenols in creosote and creosote-treated wood products such as railway sleepers and stakes for agricultural use that are either made or are procurable in Japan. PAHs were extracted with dichloromethane and analyzed by gas chromatography–mass spectrometry. Among carcinogenic PAHs, benz( a)anthracene was detected in the highest concentration, varying between 228 and 6328 μg/g in creosotes. Benzo( b)fluoranthene, benzo( k)fluoranthene and benzo( a)pyrene (BaP) were found in the range of 67–3541 μg/g. Almost all creosotes contained more than 50 μg/g of BaP, which is the upper limit level that is permitted in the European Union (EU). Creosote-impregnated wood products, such as brand-new or secondhand railway sleepers and foundations, contained large amounts of BaP (58–749 μg/g) and benz( a)anthracene (250–1282 μg/g). Concentrations of between 692 and 2489 μg/g of phenols were determined in the water extracts from creosotes, but the level was considerably less than the EU control value (3% by mass), and there was no correlation between the amount of water-extractable phenols and the amount of PAHs detected in each sample. The situation that consumers are free to use the creosotes containing a high concentration of carcinogens such as BaP may cause unacceptable damage to the health of persons handling these creosote products.