WATER QUALITY - Reporting of detergents



                                             June 24, 1965

QUALITY OF WATER BRANCH MEMORANDUM NO. 65.24

To:       District Chiefs and Staff Officials
          Quality of Water Branch

From:     Chief, Quality of Water Branch

Subject:  WATER QUALITY - Reporting of detergents

Reporting of detergents as ABS (aklyl benzene sulfonate) using
the methylene blue procedure has been the practice of the Survey.
It has been suggested that this terminology be changed to
"apparent detergents as MBAS" (methylene blue active substances)
for the following reasons:

1.   The detergent industry is gradually discontinuing the
     use of ABS in household synthetic detergents and
     replacing it with LAS (linear alkylate sulfonate).
     With this change over from hard to soft detergents the
     methylene blue procedure may still react to the
     incompletely degraded linear compound; therefore the
     MBAS designation will cover the substances determined
     by this procedure.

2.   Although not officially adopted, the terminology
     "Apparent detergents as MBAS," is well known and in
     general use by the detergent industry, and by state and
     other federal agencies.

Since most of our records for the annual reports series for the
1964 water year are now being processed at the Records Processing
Centers, it is not expected that changes be made in terminology
for the reported detergents.  Beginning with the 1965 water year,
all data designated as "ABS" will be changed to "Detergents as
methylene blue active substances" (MBAS) prior to submitting
annual records to the RPC.  This designation will continue until
such time as an analytical procedure is available for routine use
which will identify the detergent substances.



                                   S. K. Love

WRD Distribution:  A, B, S4, FO4, SL