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Correspondence between occupational exposure limit and biological action level values for alkoxyethanols and their
1Kuopio Regional Institute of Occupational Health, Finland. Juha.Laitinen@occuphealth.fi
Objectives:
The Finnish occupational exposure limit (OEL) values for alkoxyethanols and their acetates were lowered in 1996. A reevaluation of the correspondence between the new OEL value and the biological action level (BAL) was thus needed. This study was conducted in silkscreen printing enterprises, where 2-alkoxyethanols and their acetates are mainly used as solvents. The air/urine correlations between 2-methoxyethylacetate, 2-ethoxyethylacetate, 2-butoxyethanol, 2-butoxyethylacetate, and 2-methoxyacetic (MAA), 2-ethoxyacetic (EAA), and 2-butoxyacetic acid (BAA) were evaluated on an individual and time-related basis at four different enterprises.
Methods:
Inhalation exposure to alkoxyalcohols and their acetates was monitored with diffusion badges (n = 38) for an entire work week. Urinary excretion of alkoxyacetic acids immediatley after the shift and at 14-16 h after exposure (n = 112) was analyzed by a gas chromatograph equipped with a flame-ionization detector.
Results:
Inhalation exposure to 2-methoxyethylacetate at 0.5 cm3/m3 corresponded to MAA excretion of 3 mmol/mol creatinine in urine at 14 to 16 hours after exposure. The next-morning urinary EAA excretion of 37 mmol/mol creatinine corresponded to an 8-h 2-ethoxyethylacetate exposure of 2 cm3/m3 when all collected data were included. This average EAA excretion was 69% of the German BAT value and only 34% of the American biological exposure index (BEI) value. Urinary EAA excretion was 30-40% lower at the beginning of the work week than at the end of the work week. On the other hand, EAA excretion was 10-20% higher than that measured at 14-16 h after exposure. Urinary BAA excretion of 75 mmol/mol creatinine in postshift urine corresponded to an 8-h 2-butoxyethanol and 2-butoxyethylacetate exposure of 5 cm3/m3. This BAA excretion was 87% of the German BAT value.
Conclusion:
According to these results, it seems that the BAL for MAA and EAA should be 3 and 50 mmol/mol creatinine as measured at 14-16 h after exposure, respectively. The BAL value for BAA seems to be 70 mmol/mol creatinine in postshift samples. These recommendations are valid only if samples are collected at the end of the work week.