Abstract for Poster 26

 

 

Assessment of skin exposure to resin acids during the production of wood pellets using the tape-strip method

K. Hagström*¹, K. Eriksson², S. Axelsson¹, I.L. Bryngelsson¹, L.A. Nylander-French^3
1Dept. of Occupational and Environmental Medicine, Örebro, Sweden
²Dept. of Occupational and Environmental Medicine, Umeå, Sweden
³Dept. of Environmental Sciences and Engineering, Chapel Hill, United States

Background

The environmental and energy policy in Sweden is aiming to replace fossil energy with renewable sources such as bio fuels, e.g. wood pellets produced from shavings and sawdust of pine and spruce. Resin acids are present in the wood and resin from these wood species. During production of wood pellets, air levels of wood dust have been shown to be high - up to 19 mg m^-3. Wood dust and resin acids may contaminate the skin of the workers following deposition and/or contact with contaminated surfaces. Health effects like airway and skin irritation have been described for resin acids. The aim of the study was to measure the dermal exposure to resin acids using a tape-strip method during industrial production of wood pellets.

Material and Methods

Five measurement periods were performed at three companies producing wood pellets. A total of 26 subjects were included in the study of whom 9 provided tape-strip samples twice; a total of 35 measurements. Three consecutive tapes were collected at each exposure site (LeukosilkÒ, 2.5 cm x 4.0 cm). The exposure sites included forehead, front of neck, lower forearm, and the palm of the hand. Measurements were performed before and after work shift and a total of 24 tapes per subject and measurement occasion were collected. The resin acids analysed were 7-oxodehydroabietic acid, dehydroabietic acid, abietic acid, and pimaric acid using LC-MS analysis. The limits of quantification (LOQ) for the acids were 15, 250, 150, and 300 ng/tape, respectively.

 

Table 1. Levels of 7-oxo- and dehydroabietic acids in each exposure site (neck= front of neck, arm= lower forearm, hand = the palm of the hand), by sampling time, and in each tape. The number of tapes (N) and the number of tapes below the limit of quantification (N < LOQ) is also reported.

 

				Levels (ng/tape)
		N		7-oxodehydro- abietic acid	Dehydro- abietic acid
Exposure site	Forehead	210	N < LOQ	126	176
			Maximum	520	2 800
	Neck	210	N < LOQ	147	181
			Maximum	380	3 700
	Arm	210	N < LOQ	149	179
			Maximum	840	9 700
	Hand	210	N < LOQ	113	178
			Maximum	700	3500
Sample time	Before shift	420	N < LOQ	359	393
			Maximum	140	3 100
	After shift	420	N < LOQ	176	321
			Maximum	840	9 700
Tape	No 1	280	N < LOQ	137	218
			Maximum	840	9 700
	No 2	280	N < LOQ	191	245
			Maximum	300	3 000
	No 3	280	N < LOQ	207	251
			Maximum	220	3 700
Total		840	N < LOQ	535	714
			Minimum	< 15	< 250
			Maximum	840	9 700

 

Results and discussion

The levels for most of the samples of 7-oxodehydroabietic, dehydroabietic, abietic, and pimaric acid were below the LOQ (64%, 85%, 95%, and 99.5%, respectively). The levels for 7-oxo- and dehydroabietic acid ranged from <15 to 840 ng/tape, and from <250 to 9,700 ng/tape, respectively (Table 1). Higher levels were observed after the work shift than before. Generally the amounts of resin acids were lower in the second and third tapes compared to the first tape. Interestingly, in some cases an increase of the amount of 7‑oxo- and dehydroabietic acid in the second and third tapes compared to the first tape was observed. In addition, the amount in the third tape was higher compared to the second tape.  This was more common for dehydroabietic acid (n= 60) than 7-oxodehydroabietic acid (n=26) for which a larger variation was also observed (11-2800 ng/tape and 2‑88 ng/tape, respectively). This implies that resin acids penetrate the epidermis.

Conclusion

In conclusion, dermal exposure to resin acids has been observed during industrial production of wood pellets.  An increase in the levels of 7-oxodehydroabietic and dehydroabietic acids were observed in the end-of-work shift samples compared to the samples collected before the work shift. In some individuals an increase of 7-oxo- and dehydroabietic acids were observed in the second and third tapes compared to the first tapes. These results indicate that resin acids may penetrate the epidermis and, thus, be available for skin metabolism and systemic circulation.

 

Content last modified: 22 May 2005