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The metalworking fluids (MWFs) also known as coolants, cutting fluids or lubricants are mainly oils or any other liquids that are used in most of the machining operations to reduce the interfacial temperature of the work material and the cutting tool. The MWFs also help in reducing the friction generated between the machining zones by lubricating the contact area (Osama et al., 2017). The MWFs are also expected to increase the tool life, reduce the surface roughness, remove the chips from the machining area, and reduce the wear (Nune & Chaganti, 2019; E. A. Rahim and Sasahara, 2011; Siniawski and Bowman, 2009). MWFs are mainly obtained from the mineral based, petroleum based or vegetable-based fluid. Currently, the use of the MWFs has increase multifold because they offer many benefits. The European Union (EU) utilizes about 320,000 tonnes of MWFs/year. Out of this around 1/3rd is used and 2/3rd is required to be discarded. As of today, in the United States more than 1 million machining operators are made vulnerable to the exposure of machining lubricants (Vamsi et al, 2011) (Lawal et al., 2012). The global consumption of MWFs was 38 million metric tonnes and is estimated to increase by 1.2% over the next decade (Najiha et al., 2016). Due to this multifold increase of the use in lubricants there has been a noteworthy adverse biological effect on human health (Gupta et al., 2016).
Moreover, many recent and past studies have reported that the contact of lubricant with the human body is the major cause of respiratory and skin diseases. The effect can even escalate to a level where workers have been diagnosed with serious illness like organ failure and cancer (Krolczyk et al., 2019; Abdalla et al., 2007). In 2001, a study (Eisen et al., 2001) showed the drastic effect of lubricants on humans. It was reported that even at an exposure level of 1 mg/m3 which is way less than the permissible limits, the effect on human body were as bad as smoking cigarettes for the entire year. One more study reported that an automobile company in France diagnosed chronic respiratory symptoms in more than 300 workers who were exposed to lubricant level which were half of the recommended value of 5.0 mg/m3 (Huynh et al., 2009). Other than common skin diseases, other serious diseases like cancer is also associated with the consumption of petroleum and mineral oil-based lubricants (Xavior and Adithan, 2009) (Greaves et al., 1997).