Comment - 21763 - Eurofins Eaton Analytical, LLC

Need to consider the limitations of current analytical technologies and methods. The most sensitive drinking water method is probably EPA 522 that can provide a minimum report leveling (MRL) of 0.07 µg/L as that used in the third Unregulated Contaminant Monitoring Rule (UCMR 3). EPA 522 also requires that acceptable laboratory method blanks (LMB) must be less than one-third of the MRL. Therefore, it is extremely difficult to achieve a practical MRL of 0.04 µg/L, which will require an LMB of less than 0.013 µg/L.