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A model for predicting endotoxin concentrations in metalworking fluid sumps in small machine shops
D Park1, K Teschke, K Bartlett
1Department of Environmental Health, Korea National Open University, Dongsung-dong, Jongro-ku, Seoul, South Korea, 110-791.
The Annals of Occupational Hygiene
|October 5, 2001
Summary
Controlling endotoxin contamination in metalworking fluids (MWF) is crucial. Minimizing tramp oil, using synthetic fluids, and monitoring pH and temperature can significantly reduce endotoxin levels in MWF sumps.
Area of Science:
- Industrial Hygiene
- Occupational Health
- Environmental Science
Background:
- Metalworking fluids (MWF) are widely used in machining operations.
- MWF can become contaminated with endotoxins, posing potential health risks to workers.
- Understanding factors influencing endotoxin levels in MWF is essential for risk management.
Purpose of the Study:
- To investigate the concentration of endotoxins in water-based MWF sumps.
- To identify factors influencing MWF sump endotoxin levels in small machine shops.
- To provide recommendations for controlling endotoxin contamination.
Main Methods:
- Samples from 140 MWF sumps across 19 machine shops in British Columbia were collected.
- Endotoxin levels were quantified using the Limulus Amoebocyte Lysate assay.
- Mixed-effects multiple regression modeling was employed to analyze influencing factors.
Main Results:
- The geometric mean endotoxin concentration was 6791 EU/ml.
- Tramp oil contamination, lower pH (<8.5), use of soluble fluids, and higher temperatures (>32°C) significantly increased endotoxin levels.
- Higher MWF temperatures showed a strong positive correlation with increased endotoxin concentrations.
Conclusions:
- Minimizing tramp oil contamination is key to reducing endotoxin levels.
- Utilizing synthetic MWF, maintaining pH between 8.5-9.5, and controlling temperature are effective strategies.
- Within-shop correlation suggests a need for comprehensive fluid management.
