Comment submitted by Robert J. Polis, Metropolitan Water Reclamation District of Greater Chicago (MWRD)

Comment 1: The Metropolitan Water Reclamation District of Greater Chicago ("District") concurs with the EPA’s decision to reconsider promulgating method ASTM D7575-10 as an alternative (not a replacement) for EPA Method 1664A. Additionally, pending further instructions from the EPA, the District would consider using ASTM D7575-10 after the useful lifespan of its existing equipment – used for method 1664A determinations – has expired. We applaud the EPA’s continued diligence in considering green initiatives that will either minimize or eliminate the use of solvents in analytical procedures and the analysts’ exposure to these solvents. Comment 2: The District likewise concurs with the EPA’s conclusion that permit limit adjustment based on side-by-side comparisons of EPA Method 1664A and ASTM D7575-10 is not appropriate. Comment 3: If the EPA allows side-by-side comparison of EPA Method 1664A and ASTM D7575-10 to establish a conversion factor, then the approach should be similar to the one used when the EPA promulgated EPA Method 1664A (which uses n-hexane as the solvent) to replace EPA Method 413.3 (which used Freon as the solvent).