| IJOMEH
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INTERNATIONAL JOURNAL OF OCCUPATIONAL MEDICINE AND ENVIRONMENTAL HEALTH
Current website - http://ijomeh.eu
Int. J. Occup. Med. Environ Health 2007;20(4):365-371 |
DOI 10.2478/v10001-007-0036-y |
MARCIN CYPROWSKI, MAŁGORZATA PIOTROWSKA, ZOFIA ŻAKOWSKA, IRENA SZADKOWSKA-STAŃCZYK |
Abstract
The present study is a part of a larger project on assessment of
exposure to biological agents and respiratory health effects among
metal workers. Objectives: The aim of this study was to
evaluate the level of microbial contamination of metalworking coolants
as a potential source of harmful biological agents in three different
metal industry plants in Poland. Material and Methods: Ten
samples of coolants with a different state of wear, including four
fresh fluids, were analyzed. Qualitative and quantitative analysis of
bacteria and mould content was performed using standard analytical
methods. Bacterial endotoxin concentration was determined by the
kinetic, chromogenic version of the LAL test. Results: The analysis showed the total bacterial counts ranging from 1.0x101 CFU/ml to 3.2x107
CFU/ml, 60% to 100% of which were Gram-negative bacteria capable of
producing endotoxins. Among the highly contaminated coolants, one
unused concentrate was also found. The predominant species of bacteria
was Shewanella putrefaciens present in 60% of the samples. As for moulds, the predominant species was Acremonium butyri.
The average concentration of bacterial endotoxins was 773 EU/ml in the
old coolants, and much lower in the fresh fluids 285 EU/ml. A
correlation (r = 0.66) was found between endotoxin concentration and
the number of Gram-negative bacteria detected in the coolants. Conclusion:
Procedures should be developed for cleaning tanks during fluid
replacement to minimize the risk of bacterial growth in the coolants
and limit bioaerosol emission in workplace. Due to the affinity of
microflora for the water phase, it is advisable to use effective
biocides with appropriate partition coefficient between the water phase
and oil phase.
Key words
Metalworking fluids, Bacterial and mould contamination, Endotoxins![](images/buttons/buynum_blue_EN.gif)