Lab Blank Contamination Check

The DQM Check for Lab Blank Contamination identifies detected concentrations of target analytes in laboratory blanks. If a detected analyte in a laboratory blank is also contained in an associated sample at a similar level as that in the blank, DQM will qualify the associated sample result.

Check

The check name is EarthSoft.DQM.LabBlankContamination.

Parameters

This check uses four Global Parameters:

1.reportable_result – DT_RESULT.REPORTABLE_RESULT values to include in DQM datasets

2.result_type_code – DT_RESULT.RESULT_TYPE_CODE to include in DQM datasets

3.test_type_batch – AT_TEST_BATCH_ASSIGN.TEST_BATCH_TYPE to include in DQM dataset

4.nondetect_detection_limit – Identifies which detection limit column from DT_RESULT to populate DT_RESULT.RESULT_VALUE

This check uses the following six check parameters (listed below). None of these parameters allow for input of method-specific PARAM_VALUEs. However, the common_lab_multiplier allows analyte-specific PARAM_VALUEs for each CAS_RN. Additionally, matrix-specific AND analyte- or method-specific multipliers can be used by populating RT_DQM_CONTROL_LIMITS.BLANK_MULTIPLIER. Using a multiplier from RT_DQM_CONTROL_LIMITS is discussed in more detail here.

1.LabBlankSampleType – the SAMPLE_TYPE_CODE used for laboratory blanks – defaults to "LB".

2.MethodBlankSampleType – the SAMPLE_TYPE_CODE used for laboratory method blanks – defaults to "MB".

3.Multiplier – used by DQM to determine if a result can be qualified as non-detect - defaults to 1. Must be an integer.

4.Common_lab_multiplier – used by DQM to determine if a result identified as a common laboratory contaminant can be qualified as non-detect; depends on CAS_RN field being populated and defaults to 2. Must be an integer.

5.Flag_blank – if TRUE, the laboratory blanks are also qualified – defaults to "TRUE".

6.Normal_sample_types – the SAMPLE_TYPE_CODEs used for standard association of laboratory blanks – defaults to “N”.

Note: Default parameter values listed above refer to the value provided in the DQM Starter QAPP.xlsx.

Rules

There are six rules available:

1.BLANK CONTAMINATION < QL - Contamination detected in the Blank less than the Quantitation Limit

2.BLANK CONTAMINATION >= QL - Contamination detected in the Blank greater than or equal to the Quantitation Limit.

3.RESULT/DF < QL - Associated Result / Dilution Factor < Quantitation Limit.

4.RESULT/DF >= QL OR >= BLANK * MULTIPLIER - For Blank Conc < QL, Associated Result / Dilution Factor >= Quantitation Limit OR >= multiplier * concentration detected in the associated blank.

5.RESULT/DF >= QL & < BLANK * MULTIPLIER - For Blank Conc >= QL, Associated Result / Dilution Factor >= Quantitation Limit AND < multiplier * concentration detected in the associated blank.

6.RESULT/DF >= BLANK * MULTIPLIER - For Blank Conc >= QL, Associated Result / Dilution Factor >= multiplier * concentration detected in the associated blank.

There were 3 different blank rules available in 7.21.1 and earlier builds (BLANK CONTAMINATION, RESULT > BLANK * MULTIPLIER, RESULT < BLANK * MULTIPLIER). If those 3 rules exist in a DQM QAPP, along with the 6 rules listed above, then only the 6 above rules, available starting in version 7.21.2, will be used by DQM. In order for the 3 rules available in 7.21.1 and earlier to be used by DQM, then only those 3 rules should be included in the DQM QAPP.

Associated results are found by:

1.Matching results (with detected concentrations only) by Method, Fraction, CAS_RN and TEST_BATCH_ID. If matching samples are found, the process stops.

2.If no matching results are found in Step 1, results (with detected concentrations only) are matched by Method, Fraction, CAS_RN and LAB_SDG.

Note: To use the TEST_BATCH_ID, it must be added to DT_TEST_BATCH and then the TEST_ID of the blank sample, and all of the associated TEST_IDs are added with their TEST_BATCH_ID and TEST_BATCH_TYPE to AT_TEST_BATCH_ASSIGN (usually done by EDP format).

Use of Reason Codes with the rules is discussed here.

Exceptions

For Lab Blanks

•Review blanks if Flag_blank = TRUE

•Review results with DT_SAMPLE.SAMPLE_TYPE_CODE = LabBlankSampleType and MethodBlankSampleType

•Qualify a result in a lab blank if reportable_result = Y and detect_flag=Yes

1.If BLANK CONTAMINATION < QL - the apply_remark is “Contamination detected in the Blank less than the Quantitation Limit.”
An example dqm_remark for this exception is: “[0.5 < 1] Blank result < quantitation limit in this blank.”

2.BLANK CONTAMINATION >= QL - the apply_remark is “Contamination detected in the Blank greater than or equal to the Quantitation Limit.”
An example dqm_remark for this exception is: “[8 >= 1] Blank result >= quantitation limit in this blank.”

For Associated Samples

•Review results with DT_SAMPLE.SAMPLE_TYPE_CODE = Normal_sample_types

•Qualify a result in an associated sample if reportable_result = Y and detect_flag=Yes according to the following:

1.RESULT/DF < QL - the apply_remark is “Associated Result from: Associated Result / Dilution Factor < Quantitation Limit.”
An example dqm_remark for this exception is: “[0.3 / 1 < 1] Sample result / dilution factor < quantitation limit in this associated blank: (sys_sample_code:AQ_SAMPLE1_RC_TB, analytic_method:SW6010, cas_rn:7440-28-0).”

2.RESULT/DF >= QL OR >= BLANK * MULTIPLIER – the apply_remark is “Associated Result from: For Blank Conc < QL, Associated Result / Dilution Factor >= Quantitation Limit OR >=concentration detected in the associated blank.”
An example dqm_remark for this exception is: “[5 / 1 >= 1 * 0.5] Sample result / dilution factor >= multiplier * concentration detected in this associated blank: (sys_sample_code:AQ_SAMPLE1_RC_TB, analytic_method:SW6010, cas_rn:7440-28-0)”

3.RESULT/DF >= QL & < BLANK * MULTIPLIER – the apply_remark is “Associated Result from: For Blank Conc >= QL, Associated Result / Dilution Factor >= Quantitation Limit AND < multiplier * concentration detected in the associated blank.
An example dqm_remark for this exception is: “[10 / 1 >= 1] AND [10 / 1 < 2 * 8] Sample result / dilution factor >= quantitation limit AND < multiplier * concentration detected in this associated blank:(sys_sample_code:AQ_SAMPLE1_RC_TB, analytic_method:SW6010, cas_rn:7782-49-2).”

4.RESULT/DF >= BLANK * MULTIPLIER – the apply_remark is “Associated Result from: For Blank Conc >= QL, Associated Result / Dilution Factor >= multiplier * concentration detected in the associated blank.
An example dqm_remark for this exception is: “[10 / 1 >= 1 * 8] Sample result / dilution factor >= multiplier * concentration detected in this associated blank: (sys_sample_code:AQ_SAMPLE1_RC_TB, analytic_method:SW6010, cas_rn:7782-49-2).”

Errors

1.Blank unit error
This check includes an internal unit conversion function, which allows blanks with units for liquids to be compared to results for soil samples. This internal function includes:

•ug/L to mg/kg

•ug/L to ug/kg

•mg/L to mg/kg

•mg/L to ug/kg

•Any combination of units found in RT_UNIT_CONVERSION_FACTOR will also be used.

The following error occurs if the units differ and none of the above conversion factors apply:

“Associated result has units ({0}) that do not convert to units of blank result ({1}).”

For this check to work, a record must be added to RT_UNIT_CONVERSION_FACTOR for that combination.

2.Result Numeric is null.

If the RESULT_NUMERIC column is null in the blank or the associated sample for a result, the following error message will be created:

“The RESULT_NUMERIC column is NULL in blank or associated result.”