UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
                    GUIDANCE FROM HOTLINE COMPENDIUM
                                                                          WSGH36
                                                           Date Issued:  August 1991
SUBJECT:    Secondary MCL Range for Aluminum

SOURCE:    Al Havinga
In the January 30, 1991 Phase U Rule (56 FR 3526), the list of secondary contaminants was
published in 40 CFR Section 143.3.  Aluminum was added to this list.  Why does EPA specify
a range (0.05 - 0.2 mg/1) rather than a single value for the SMCL for aluminum?

      Response:

      On page 3573 of the Final Rule, EPA provides a discussion of its decision to specify a
      range rather than a single value as the SMCL for aluminum.  In short, EPA is
      encouraging utilities to meet the optimal value of 0.05 mg/1.  EPA is aware that varying
      water quality and treatment situations may result in some systems unable to meet or have
      difficulty meeting the 0.05 mg/1 level.  Therefore,  EPA established a range, with the
      specific value being determined by the State for each system.

*Note: EPA is  still evaluating this hotline guidance.  There may be changes to this
guidance in the future.

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