Biocide Selection for Microbial Control in Metalworking Fluids under a Changing Regulatory Environment

Transcription

1 Biocide Selection for Microbial Control in Metalworking Fluids under a Changing Regulatory Environment Christine E. McInnis, Ph.D. Terry M. Williams, Ph.D.

2 Regulatory Changes Outline SCAQMD VOC Rule 1144 Triazine Options for Triazine Replacement Options for Formaldehyde Replacement 2

3 Regulatory Changes in the Metalworking Fluid Industry: Southern California Air Quality Management District VOC Rule 3

4 Southern California Air Quality Management Board Rule 1144 No person shall manufacture for use, offer for sale, sell or distribute directly to a person any metalworking fluid or direct-contact lubricant for use in the District which, at the time of sale or manufacture, contains more VOC per liter of material after recommended dilution and after the effective date as listed. Adopted Mar 2009 Amended July

5 Rule 1144 Continued Examples of allowable VOC levels effective as of January 1, 2012: Metal forming fluids: 75 g/l (0.63 lb/gal) Metal removal (general): 75 g/l (0.63 lb/gal) Precision metal removal: 130 g/l (1.08 lb/gal) Fluid VOC information can be determined from the formulated product or as a sum of their component VOCs ASTM E Standard Test Method for Loss- On-Drying by Thermogravimetry. 5

6 ASTM E : Standard Test Method for Loss-On-Drying by Thermogravimetry A sample of the metalworking fluid is heated at a constant temperature or a constant temperature gradient while its mass is continuously measured as a function of time. After a pre-determined time, the mass of the sample is recorded and the mass lost is reported as a percent of the original mass. This value is called the loss-on-drying (LOD) value. Certain volatile compounds, such as water, may be subtracted from the mass lost. 6

7 What Does Rule 1144 Mean for Biocide Use? Biocides contribute very little to the overall VOC of a MWF. Rule 1144 only applies to use-diluted fluids, not fluid concentrates. At use-dilution, biocides are present a fraction of a percent VOC in the fluid. 3% Biocide 0.15% Biocide Fluid Concentrate Use-Diluted Fluid 7

8 Regulatory Changes in the Metalworking Fluid Industry: Triazine 8

9 EPA Reregistration Eligibility Document Every 15 years biocide registrations come up for review by the EPA. All available health, safety and use data are reviewed. Additional information and test results may be required. The EPA reserves the right to modify use levels or deny reregistration for certain applications. 9

10 Biocides Recently Evaluated for Reregistration Eligibility Biocide Review Year Aza-bicyclooctane 2005 No Change BIT 2005 No Change Glutaraldehyde 2006 No Change OPP/SOPP 2006 No Change Nitro-dimorpholine 2007 No Change OIT 2007 No Change EPA Required Changes for MWFs Cationic modified ethylene 2007 No Change Triazine (HHT) 2008 Reduce use levels to 500 ppm 10

11 Triazine in MWFs (1,3,5-tris(2-hydroxyethyl)-s-triazine A formaldehyde condensate biocide frequently used in MWF concentrates Kills bacteria by releasing formaldehyde Relatively cheap and effective 11

12 US EPA and Triazine (1,3,5-tris(2-hydroxyethyl)-s-triazine Review of triazine is part of EPA program to evaluate all registered active ingredients every 15 years. Reregistration Eligibility Document (RED) dated June 27, 2008 (EPA document 739-R ) Based on mode of action for triazine, EPA addressed potential risks associated with formaldehyde exposures during use of MWF 12

13 Triazine and EPA RED Cont. A formaldehyde occupation risk exposure was conducted The cancer and non-cancer occupational handler risks for formaldehyde in metalworking fluids exceeded EPA s level of concern (inhalation) EPA concluded that triazine products could only retain the use in metalworking if product labels were modified: Reduction in the maximum use level in metalworking fluids from 1600 ppm to 500 ppm Uses removed for paints, coatings, stains, cleaners Current timing on label changes is unclear Due in part to critical review by the National Academy of Sciences 13

14 Triazine and Canada PMRA Health Canada recently also reviewed triazine for associated health risks Re-Evaluation Decision completed October 2010 (RVD ) Risk-reduction assessments indicated current use rates posed an elevated risk for human health PMRA concluded that triazine products could only retain the use in metalworking fluids, hydraulic fluids, and chain lubricants, if product labels were modified: Reduction in the maximum use level in MWF to 500 ppm Uses phased out in paints, cleaners, detergents, fabric softeners Additional efficacy data required within 24 months for continued registration (ASTM E ) 14

15 MWFs and the European Biocidal Product Directive (BPD) MWF biocides need to be registered under BPD PT 13, Metalworking-fluid preservatives. The BPD registration is done in two steps: 1) registration of the active substance PT13 dossiers submitted in 2007 All still under evaluation by the EU Competent Authorities 2) registration of individual biocidal products containing approved actives 15

16 MWF Biocide Current Situation and the European BPD As long as dossiers are under evaluation, all biocidal products containing these actives can be marketed in the EU. National requirements in the EU Member States must be fulfilled. France does not allow the use of formaldehyde releasing biocides 16

17 Supplemental Slide: Biocide Abreviations BIT = 1,2-benzisothiazolin-2-one CMIT = 5-chloro-2-methyl-4-isothiazolin-3-one DBNPA =2,2-dibromo-3-nitrilopropionamide Oxazolidines = 4,4-dimethyloxazolidine, 7-ethyl bicyclooxazolidine (BCO) IPBC = 3-iodopropynylbutylcarbamate MIT = 2-methyl-4-isothiazolin-3-one Morpholines = 4-(2-nitrobutyl)-morpholine, 4,4 -(2-ethyl-2- nitrotrimethylene)dimorpholine OIT = 2-n-octyl-4-isothiazolin-2-one Phenolics = o-phenylphenol/sodium o-phenylphenate (OPP/SOPP) Triazine = (1,3,5-tris(2-hydroxyethyl)-s-triazine (HHT) 17

18 MWF Biocides with submitted BPD Dossiers Concentrate Biocides: BCO BIT DMDMH IPBC MIT OIT OPP/SOPP Triazine Tankside Biocides: BCO CMIT/MIT DBNPA IPBC Glutaraldehyde OIT Triazine 18

19 Triazine Regulations Summary US and Canada: a 500 ppm max level for triazine has been proposed. Timing of enforcement is unclear Europe: dossiers under evaluation Some countries have additional requirements Some end users have global lists of prohibited or accepted products 19

20 The Question: What can we use to replace triazine or supplement lower dose levels in MWF? 20

21 Efficacy The Question: What can we use to replace triazine or supplement lower dose levels in MWF? Cost 21

22 Biocides for Metalworking Fluids Concentrate Tankside Eff vs Bact Eff vs Myco Eff vs Fungi HCHO Free Biocide Phenolics BIT Oxazolidines Morpholines IPBC MIT +/ OIT +/ CMIT/MIT Glutaraldehyde DBNPA Bronopol + + +/- 22

23 Selecting Biocides for MWF Concentrates Is it compatible with tankside treatments? Is it stable for long term performance? Is it compatible in all fluid types? Is it a formaldehyde-releaser? Does it kill the key organisms? Is it soluble in water and/or oil? Does it cause staining? Bactericides Oxazolidines Morpholines BIT MIT OPP/NaOPP Fungicides IPBC OIT 23

24 Comparative Features of Triazine vs Bactericides Property Triazine Oxazolines Morpholines Phenolics BIT MIT Mycobacteria Fungi No Formaldehyde Water Soluble + + +/- +/- + + ph/amine Stability /- ph Buffering + +/ No/Low Odor + +/ Non-Phenolic Non sensit/lachrym + +/ No Nitro Group Use Rate 3% 3% 2% 3-5% 3% 0.5% Easy, Drop-In Replacement for Triazine

25 Easy, Drop-in Triazine Replacement Options Biocide Features Drawbacks Oxazolidines BIT Morpholines + similar features and properties to triazine + no formaldehyde + very stable + excellent compatibility + no formaldehyde + Myco efficacy / - odor issues - possible efficacy gap - odor issues - nitrosamine concerns 25

26 Additional Triazine Replacement Options Biocide Features Drawbacks MIT + no formaldehyde + Myco efficacy - variable stability - stabilizer costs Phenolics + no formaldehyde + Myco efficacy + very stable - odor issues - discharge restrictions 26

27 Biocide Features Drawbacks BIT Formaldehyde-Free Options (ease of use) Morpholines + very stable + excellent compatibility + Myco efficacy + good stability + lower use rate + easy to formulate - possible efficacy gap - odor issues - nitrosamine concerns - low water solubility MIT + Myco efficacy - variable stability - stabilizer costs Phenolics + Myco efficacy + very stable - odor issues - discharge restrictions 27

28 Potential Formaldehyde-Free Combos (easy drop-in) Biocide Combination BIT + Nitrodimorpholine Added Value vs Triazine + Easy to formulate in concentrates + Good stability + Good bacterial/fungal spectrum/myco efficacy + Lower odor vs nitro-dimorpholine alone + Formaldehyde free - Potential odors / sensitization - Nitrosamine concerns 28

29 Summary Several recent regulatory changes are impacting biocide selection for the MWF industry VOC formulations limits for CA Triazine restrictions for biocide dosing Consider what features are important for your formulation when choosing a triazine replacement 29

30 Questions? 30