BRANCH OF TECHNICAL DEVELOPMENT AND QUALITY SYSTEMS MEMORANDUM
NO. 95.01
SUBJECT: ADP--Storage of water-quality quality-assurance data in
NWIS
Branch of Quality Assurance Memorandum Number 90.03 presented
definitions and methods for identifying QC samples in the NWIS-I
software. New medium codes were added to clearly distinguish
quality-control samples from environmental samples. Four of the
medium codes identified in the memo were in error:
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Medium Correct Code Code in BQA
Memo 90.03
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Quality-Assurance Sample -- Bottom Material W Z
Quality-Assurance Sample -- Animal Tissue X W
Quality-Assurance Sample -- Plant Tissue Y X
Quality-Assurance Sample -- Interstitial Water Z Y
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The enclosures from BQA Memo 90.03 are repeated in this memo
with the appropriate corrections to the medium codes.
William J. Shampine
Chief
Branch of Technical Development
and Quality Systems
Enclosures:
(1) Definitions of quality assurance data
(2) Identification of quality assurance data in NWIS-I
(3) Lists of codes added to NWIS-I
Dist. A, B, S, FO, PO
This memorandum supercedes Branch of Quality Assurance
Memorandum 90.03.
Definitions of Quality-Assurance Data
_____________________________________
Blank samples are taken to ensure that environmental samples have
not been contaminated by the data-collection process. Any
measured value/signal in a blank sample for an analyte (a
specific component measured in a chemical analysis) that was
absent in the blank solution is believed to be due to
contamination. There are many types of blank samples possible,
each designed to segregate a different part of the complete data-
collection process including sampling, filtering, preserving,
storing, transporting, and analyzing:
Blank solution - Solution that is free of the analyte(s) of
interest. Such a solution would be used to develop specific types
of blank samples as described below.
Shelf (or hold) blank - a blank solution that is put in the same
type of bottle used for an environmental sample and stored
adjacent to an environmental sample in a storage area.
Refrigerator blank - a blank solution that is put in the same
type of bottle used for an environmental sample and stored
adjacent to an environmental sample in a refrigerated storage
area.
Trip blank - a blank solution that is put in the same type of
bottle used for an environmental sample and kept with the set of
sample bottles both before and after sample collection.
Sampler blank - a blank solution that is poured or pumped through
the same field sampler used for the collection of an
environmental sample.
Filter blank - a blank solution that is filtered in the same
manner and through the same filter apparatus used for an
environmental sample.
Splitter blank - a blank solution that is mixed and separated
using a field splitter in the same manner and through the same
apparatus used for an environmental sample.
Preservation blank - a blank solution that is treated with the
same preservatives used for an environmental sample.
Field blank - a blank solution that is subjected to all aspects
of sample collection, field processing, preservation,
transportation, and laboratory handling as an environmental
sample.
Blind sample - A sample submitted for analysis whose composition
is known to the submitter but unknown to the analyst. A double
blind sample is one of known composition that is submitted to the
analyst in such a manner that neither its composition nor its
identification as a check sample is known to the latter. A blind
sample is one way to test the proficiency of a measurement
process. Blind samples can be used to monitor the performance of
an analytical system, check the analytical results of more than
one laboratory, more than one analytical method, or the
consistency of the same laboratory and method. Every blind sample
analyzed should have an associated reference to the source and
the possible dilution. Blind samples may be prepared from a
reference material, as defined below.
Reference material - A material or substance one or more
properties of which are sufficiently well established to be used
for the assessment of a measurement method or for assigning
values to materials.
Replicate (Duplicate) samples - A group of samples, collected in
a manner such that the samples are thought to be essentially
identical in composition. Replicate is the general case for which
duplicate is the special case consisting of two samples. There
are many types of replicate samples possible, each of which may
yield slightly different results in a dynamic hydrologic setting,
such as a flowing stream. The types of replicate samples are:
Concurrent samples - samples collected by two or more people
collecting samples simultaneously, or by one person alternating
subsamples between two or more collection bottles.
Sequential sample - a type of replicate sample in which the
samples are collected one after the other, typically over a short
period of time.
Split sample - a type of replicate sample in which a sample is
split into subsamples contemporaneous in time and space.
Spike sample - A sample to which known concentrations of specific
analytes have been added in such a manner as to minimize the
change in the matrix of the original sample. Every spiked sample
analyzed should have an associated reference to the spike
solution and the volume added.
Spike solution - A solution with one or more well established
analyte concentrations that is added in known quantities to an
environmental sample to form a spike sample.
Identification of Quality-Assurance Data in NWIS
________________________________________________
A system for identifying quality-assurance samples and
maintaining the relationship with corresponding environmental
samples has been established. The MEDIUM CODE, DATE, TIME and
SAMPLE TYPE are used in the following manner to identify clearly
all QA data:
Blank -
(1) Use actual STATION NUMBER, DATE and TIME for blanks
associated with a specific site and environmental sample. Use
artificial STATION NUMBER, DATE and TIME for blanks that are
associated with many sites and/or environmental samples. If more
than one blank is analyzed, increment the TIME by 1 minute for
each blank.
(2) Use a MEDIUM CODE of Q (new code).
(3) Use a SAMPLE TYPE of 2 (new code).
(4) Use new parameter codes to designate which type of blank
solution, the source of the blank solution, and the type of blank
sample.
(5) If more than one blank is collected, use parameters 82073 and
82074 to enter the same STARTING TIME and ENDING TIME for each
blank.
Blind -
(1) Use actual STATION NUMBER, DATE and TIME for blinds
associated with a specific site and environmental sample. Use
artificial STATION NUMBER, DATE and TIME for blinds associated
with many sites and/or environmental samples. If more than one
blind is analyzed, increment the TIME by 1 minute for each blind.
(2) Use a MEDIUM CODE from Q-Z (new codes).
(3) Use a SAMPLE TYPE of 4 (new code).
(4) Use new parameter codes to designate the source of the
reference material and the source code number.
(5) If more than one blind is collected, use parameters 82073 and
82074 to enter the same STARTING TIME and ENDING TIME for each
blind.
Reference Material -
(1) Assign an artificial STATION NUMBER.
(2) Use the DATE and TIME that material was created or received.
(3) Select a MEDIUM CODE from Q-Z (new codes).
(4) Use a SAMPLE TYPE of 6 (new code).
(5) Use new parameter codes to designate the source of the
reference material and the source code number.
Replicate -
(1) Use the existing STATION NUMBER.
(2) Use actual DATE and TIME for the 1st sample and increment
TIME by 1 minute (or actual times if greater than 1 minute) for
each additional sample.
(3) Select a MEDIUM CODE from Q-Z (new codes).*
(4) Use a SAMPLE TYPE of 7 for every sample, including the first
one.
(5) Use a new parameter code for replicates to designate which of
the methods was used to create the replicates.
(6) Use the same STARTING TIME and ENDING TIME (parameters 82073
and 82074) for all samples.
* If the replicate samples will be stored in the regular data
base, use normal MEDIUM CODES (i.e., 6 or 9) and a sample type of
7.
Spike -
(1) Use actual STATION NUMBER, DATE and TIME for spikes
associated with a specific site and environmental sample. Use
artificial STATION NUMBER, DATE and TIME for spikes that are
associated with many sites and/or environmental samples. If more
than one spike is analyzed, increment the TIME by 1 minute for
each spike.
(2) Select a MEDIUM CODE from Q-Z (new codes).
(3) Use a SAMPLE TYPE of 1.
(4) Use new parameter codes to designate the source code number
of the spike solution, the spike type, and the volume of the
spike. Use an existing code (32000) to designate the sample
volume.
(5) If more than one spike is collected, use parameters 82073 and
82074 to enter the same STARTING TIME and ENDING TIME for each
spike.
Spike Solution -
(1) Assign an artificial STATION NUMBER.
(2) Use the DATE and TIME that source was created or received.
(3) Use a MEDIUM CODE of Q (new code).
(4) Use a SAMPLE TYPE of 8 (new code).
(5)Use new parameter codes to designate the source of the spike
solution and the source code number of the spike solution.
A DISTRICT PROCESSING STATUS code of Z (local use only) should be
assigned to each QA sample to prevent the data from being
transferred to the national data base and subsequently to the
EPA's STORET data base.
New Codes
_________
Medium Codes
Q Quality-Assurance Sample -- Artificial
R Quality-Assurance Sample -- Surface Water
S Quality-Assurance Sample -- Ground Water
T Quality-Assurance Sample -- Wet Deposition
U Quality-Assurance Sample -- Bulk Deposition
V Quality-Assurance Sample -- Suspended Sediment
W Quality-Assurance Sample -- Bottom Material
X Quality-Assurance Sample -- Animal Tissue
Y Quality-Assurance Sample -- Plant Tissue
Z Quality-Assurance Sample -- Interstitial Water
Sample Types
1 *Spike
2 Blank
3 *Reference
4 Blind
5 *Duplicate
6 Reference Material
7 *Replicate
8 Spike Solution
B Other Quality Assurance
* Existing sample types that apply to quality assurance data
Remark Codes
A Average value
V Variance
S Most probable value
Parameter Codes
99100 Blank, Type of solution (fixed value)
10.00 Distilled/deionized Water
20.00 Standard Reference Water Sample
30.00 Matched Matrix
40.00 Organic-free water
200.00 Other
99101 Blank, Source of solution (fixed value)
10.00 National Water Quality Lab
20.00 U.S. Environmental Protection Agency
30.00 Standard Reference Water Sample (USGS)
35.00 Mix of Standard Reference Water Samples
40.00 NIST (formerly NBS)
50.00 Canadian Inland Waters
60.00 District lab
70.00 Natural sample
80.00 Ocala Lab
99.99 Unknown
100.00 Chemical Supplier
200.00 Other
99102 Blank, Type of sample (fixed value)
10.00 Shelf (hold)
20.00 Refrigerator
30.00 Trip
40.00 Sampler
50.00 Splitter
60.00 Filter
70.00 Preservation
100.00 Field
200.00 Other
99103 Reference Material, Source (fixed value)
10.00 National Water Quality Lab
20.00 U.S. Environmental Protection Agency
30.00 Standard Reference Water Sample (USGS)
35.00 Mix of Standard Reference Water Samples
40.00 NIST (formerly NBS)
50.00 Canadian Inland Waters
60.00 District lab
70.00 Natural sample
80.00 Ocala Lab
99.99 Unknown
100.00 Chemical Supplier
200.00 Other
99104 Reference Material or Spike Source, Code Number
99105 Replicate, Type (fixed value)
10.00 Concurrent
20.00 Sequential
30.00 Split
40.00 Split-concurrent
50.00 Split-sequential
200.00 Other
99106 Spike, Type (fixed value)
10.00 Field
20.00 Laboratory
30.00 Surrogate
40.00 Internal Standards
200.00 Other
99107 Spike, Source (fixed value)
10.00 National Water Quality Lab
20.00 U.S. Environmental Protection Agency
30.00 Standard Reference Water Sample (USGS)
35.00 Mix of Standard Reference Water Samples
40.00 NIST (formerly NBS)
50.00 Canadian Inland Waters
60.00 District lab
70.00 Natural sample
80.00 Ocala Lab
99.99 Unknown
100.00 Chemical Supplier
200.00 Other
99108 Spike Volume