Permeation of a Metalworking Fluid Through a Latex

Authors: Wenhai Xu Shane S Que Hee

Publish Date: 2009/09/26

Volume: 84, Issue: 1, Pages: 5-

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Abstract

Whole glove testing for a metalworking fluid MWF in the field was performed for the first time Green latex gloves used in a machine shop were exposed for 20 min to MWF The permeated amount 10 ± 05 μg/cm2 was higher than the threshold 025 μg/cm2 for the ASTM F73999a closedloop normalized breakthrough timeThe composition and the adverse health effects of metalworking fluids MWFs are well researched Byers 1994 NIOSH 1998 Xu and Que Hee 2006a MWFs are complex blended mixtures that not only contain petroleum distillate but also additives The performance of disposable gloves against MWFs has been tested in the laboratory in permeation cells Xu and Que Hee 2006b 2007 2008a Only flat material can be examined ASTM 2004 work factors are not simulated the test temperature differs from the actual temperature of gloved hands and whole gloves are not tested Klingner and Boeniger 2002 ASTM 2004 Phalen and Que Hee 2008 In the present study the first field study of glove permeation of a MWF the permeation of whole gloves was investigated in a metalworking shopThe metalworking fluid used was New Rapid Tap from Relton Arcadia CA It contained mineral oil CAS 64742581 50 weight chlorinated paraffins CAS 61788769 40 additives patent 8 epoxidized soybean oil CAS 8013078 1 olefin sulfide patent 1 and cinnamon oil trace The glove was DermaThin a green natural rubber latex glove Best Manufacturing Company Menlo GA Workers could have gloves as needed The mass per unit area of three gloves was determined with cut pieces at the palm area These data and the mass of the whole glove led to an average total outer surface area of 581 ± 16 cm2 The glove thickness was 0122 ± 0004 mm from seven measurements for each of three gloves The worker operated a Hardinge SuperPrecision lathe Elmira NY Most manipulations required both hands During the metalworking process the worker held a tin can of Rapid Tap fluid upside down in his rightgloved hand to drip the MWF on the turning metal tube and lathe MWF mist formed when MWF dripped on the turning tube The worker then removed the tube from the lathe and sprayed acetone to clean the tube A cotton cloth was used to wipe the lathe and treatment with compressed air and a sand cloth improved the finish The whole cycle took some 60 min There was no local exhaust system A machine guard was available but was flipped open to allow a better view No respirators were used The worker first washed his hands with liquid soap before putting on the method blank gloves The latter were removed after 2 min without touching metal pieces or MWF Fresh gloves were then donned and two drops 53 ± 2 mg of MWF was applied on the palm of the glove The worker rubbed the palms of the two gloves together but did not touch the glove on the backs of the hands The worker did the shop job as indicated above After 20 min the investigators wearing fresh gloves eased the exposed gloves off the worker’s fingers by gentle pulling and removed the gloves The glove cuff was then tied by a rubber band Throughout the process care was taken to avoid contamination of the glove inner surface Each exposed glove was deposited in a labeled acidwashed 50 mL wide mouth Pyrex Mason jar with Teflon lined screw cap Transfer to the laboratory occurred within 10 min Three pairs of exposed gloves were obtained in totalIn the laboratory the glove was taken out of the jar by gloved hands and the rubber band removed About 5 mL perfluorohexane 985 purity from Apollo Scientific Bredbury Cheshire UK Xu and Que Hee 2006a 2008b Phalen and Que Hee 2008 was pipetted into the inside of the glove through the small opening at the glove wristend The opening was then closed the glove shaken up and down for 10 s kneaded 15 s to ensure that perfluorohexane wet the entire inner surface and shaken further for another 5 s The perfluorohexane was then dripped into a 20 mL acidwashed glass vial with Teflonlined screwcap Five such rinses were done for each glove Each rinse was analyzed by gas chromatographymass spectrometry GCMS by the total ion current monitoring mode m/z 50–400 and using the conditions described elsewhere Xu and Que Hee 2006a except for the GC column temperature program The 30 m × 025 mm HP5 capillary column was held at 150°C for 15 min heated at 20°C/min to 250°C and held at 250°C for 13 min Aliquots of 10 μL of each rinse and the standard solutions of 0 22 44 66 88 and 110 ng/μL of Rapid Tap MWF were injected in perfluorohexane solution Standard curves were linearized by BoxCox power transformation Xu and Que Hee 2006aThe glove fingers and palm area became black from manipulating the work piece and tools especially on the thumb index and middle fingers The lower quantifiable limit of MWF was 44 ng The standard curve of GCMS area versus injected MWF mass had a correlation coefficient r of 0912 p  001 and a slope of 54 × 108 area unit/μg and an intercept of 25 × 107 area unit A BoxCox power transformation indicated the optimum power was 01 The new standard curve of area01 versus injected MWF mass with a slope of 19 area unit01/μg and an intercept of 36 area unit01 had r = 0982 and p  001 The standard curve using transformed data fit all the MWF data The method blank glove rinses showed no MWF Thus the worker’s hands were clean at the beginning of the test and there was no contamination from handling by the investigatorsThis project was funded by the UCLA Center for Occupational and Environmental Health COEH ASPH/NIOSH S189121/21 and NIOSH OH03754 Robert N Phalen is thanked for valuable discussions The UCLA Human Subjects Internal Review Board determined this study required no Human Subject Consent FormThis article is published under an open access license Please check the Copyright Information section for details of this license and what reuse is permitted If your intended use exceeds what is permitted by the license or if you are unable to locate the licence and reuse information please contact the Rights and Permissions team

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