Table of Contents

This document contains the aggregated coding from BQA Memos 90.03, 92.01 and 95.01 to use for storing QC samples in NWIS-I.


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.
Ambient blank - a blank solution that is put in the same type of bottle used for an environmental sample, kept with the set of sample bottles before sample collection, and opened at the site and exposed to the ambient conditions.
Equipment blank - a blank solution that is processed through all equipment used for collecting and processing an environmental sample (similar to a field blank but normally done in the more controlled conditions of the office and not being transported to the field).
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.
Filter blank - a blank solution that is filtered in the same manner and through the same filter apparatus used for an environmental sample.
Lab blank - a blank solution prepared in the laboratory and analyzed the same as an environmental sample.
Preservation blank - a blank solution that is treated with the same preservatives used for an environmental sample.
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.
Sampler blank - a blank solution that is poured or pumped through the same field sampler used for the collection of an environmental sample.
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.
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.
Source solution blank - a blank solution sent to a laboratory to confirm that it is free of the analyte of interest.
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.
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
50.00 VOC 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
61.00 Subdistrict #1 Lab
62.00 Subdistrict #2 Lab
63.00 Subdistrict #3 Lab
64.00 Subdistrict #4 Lab
70.00 Natural sample
71.00 Field Office #1 Lab
72.00 Field Office #2 Lab
73.00 Field Office #3 Lab
74.00 Field Office #4 Lab
80.00 Ocala Lab
99.99 Unknown
100.00 Chemical Supplier
110.00 Burdick And Jackson
120.00 J.T. Baker
200.00 Other
99102 Blank, Type of sample (fixed value)
1.00 Source Solution
10.00 Shelf (hold)
20.00 Refrigerator
30.00 Trip
40.00 Sampler
50.00 Splitter
60.00 Filter
70.00 Preservation
80.00 Equipment
90.00 Ambient
100.00 Field
150.00 Lab Blank
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
99109 Starting date for a set of samples (YMMDD)
99110 Ending date for a set of samples (YMMDD)
99111 Quality assurance data type associated with sample, fixed value code
1.00 No associated qa data
10.00 Blank
20.00 Blind Sample
30.00 Replicate Sample
40.00 Spike Sample
100.00 More than one type of QA sample
110.00 Cross-section information stored
200.00 Other

 


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