PROGRAMS AND PLANS--Data handling; change in parameter codes for oil and grease


                                           December 8, 1978

QUALITY OF WATER BRANCH TECHICAL MEMORANDUM NO. 79.05

Subject: PROGRAMS AND PLANS--Data handling; change in parameter
                             codes for oil and grease

on January 1, 1979, the following changes will be made in the 
parameter codes used by the Denver and Atlanta Central 
Laboratories to report and store data on oil and grease in samples 
containing fluvial sediments. .The changes were necessary because 
the parameter codes previously used in WATSTORE have been 
identified within the STORET System with specific analytical 
methods that are not now in use at our central laboratories.
Changes made are indicated below:

Old       New
Code      Code             Parameter name of new code

00550     00556      Oil-Grease, total recoverable, gravimetric,
                     freon-extractable (mg/l)

00553     00557      Oil-Grease, recoverahle from bottom material,
                     gravimetric, freon extractable, dry wt. 
                     (mg/kg)

The freon extraction methods have been used by the central 
laboratories since 1974. The two formerly used parameter codes, 
00550 and 00553, are still valid codes and according to FPA they 
designate determinations made by the Soxhlet extraction method for 
total recoverable oil and grease and the hexane extraction method 
for oil and grease recoverable from bottom material, respectively. 
In WATSTORE these code designations will be used to store pre 1974 
data and new data not produced using freon extractions. Because a 
significant fraction of the analytical data on oil and grease that 
were placed in STORET during the period 1974 to present did not 
come from the Central Laboratories, no attempt will be made 
nationally to effect a mass chance of parameter codes for data 
stored during that period. It is strongly recommended, however, 
that districts update any data that they are sure came from the 
central laboratories since 1974, or any other data stored under 
the old codes that are known to have been obtained by the freon-
extraction methods.  Districts that hare a large number of 
stations with data to be updated can obtain assistance by 
contacting the ADP unit in Reston, FTS 928-7131.



                                R.J. Pickering
                                Chief, Quality of Water Branch

WRD Distribution: A, B, S, FO, PO