Acta Facultatis Ecologiae - Technická univerzita vo Zvolene

67ACTA FACULTATIS ECOLOGIAE, 15: Suppl. 1, 67–75 Zvolen (Slovakia), 2007SELECTED METALWORKING FLUIDSBIODEGRADABILITY AND ECOTOXICITY EVALUATIONKristína Gerulová − Stanislav Hostin – Anna MichalíkováKatedra environmentálneho inžinierstva, Ústav bezpečnostného a environmentálneho inžinierstva,Materiálovotechnologická fakulta STU v Trnave, 917 24, Paulínska 16, Trnavakistína.gerulova@stuba.sk, stanislav.hostin@stuba.sk, anna.michalikova@stuba.skABSTRACTGerulová K., Hostin S. & Michalíková A. Selected Metalworking Fluids Biodegradability and EcotoxicityEvaluationMetalworking fluids (MWFs) have been introduced into the cutting process with the purpose to improvethe characteristics of the tribological processes which are always present on the contact surfacesbetween the tool and the workpiece. Significant amounts of lubricants are lost into the environment whichpotentially affects plants, animals and human life.The main aims of this study were to evaluate the level of biodegradation of selected metalworkingfluids standards and samples from the plant by Zahn-Wellens test (OECD 302B) for inherent biodegradability,evaluate potential adsorption after 3 hours of cultivating and assessment applicability of the test formeasuring the biodegradability, evaluate the potential of activated sludge from the sewage treatment plantto degrade the selected MWFs and preliminary study to evaluate the ecotoxicity by Lemna minor.Evaluated level of tested MWFs (Emulzin H, Ecocool, BC 25) standards biodegradation by Zahn-Wellenstest achieved 80 % in 10 days, so they have a potential to ultimate degradation. Tested MWFs samplesfrom the plant pass higher level of starting COD concentration instead of this, in the case of Emulzin H andEcocool sample 2 the level of degradation pass 80 % degree.Preliminary study of ecotoxicity measuring by Lemna minor shows effective concentration of EmulzinH at the rate of 93 mg/L, for Ecocool 99 mg/L and for BC 25 about 150 mg/L. Small concentrations of testingfluids indicate the hormetic effect. It is required to test Emulzin H, Ecocool and BC 25 by semi-staticor flow-through condition.Key words: metalworking fluids, biodegradation, EC 50, machiningINTRODUCTIONMetalworking fluids have been introduced intothe cutting process with the purpose to improve thecharacteristics of the tribological processes whichare always present on the contact surfaces betweenthe tool and the workpiece [12, 13, 14].A wide variety of chemicals may be used ineach of the metal working fluid classes, and therisk these chemicals pose to workers may varybecause of different manufacturing processes, variousdegrees of refining, recycling, improperly reclaimedchemicals, different degrees of chemicalpurity, and potential chemical reactions betweencomponents through the usage [3]. Exposes of theworking environment to fluids may cause significantcontamination to the environment and healthhazards for the workers [8].Future lubricants have to be more environmentallyadapted, have a higher level of performance,and lower total life cycle cost (LCC) than presentlyused lubricants [1]. The use of rapidly biodegradablelubricants could significantly reduce environmentalpollution. Environmental friendly alternativesare available for a large variety of mineral oilbased lubricants [2]. The most interesting group for