QUALITY ASSURANCE CODES QA Usage: Chemistry QA code for an analyte in a sample QA Code QA code description CH-A The CH-A code indicates that an analyte was not detected. When the CH-A code is used, the concentration field is left blank and the method detection limit for the analyte in that particular sample is reported under Detection Limit Concentration. CH-AA Not sampled CH-B It is sometimes possible for a laboratory to detect an analyte and report its concentration at a level which is below the calculated method detection limit for the sample. In these situations the analyst is confident that the analyte was present in the sample, but there is a high degree of uncertainty in the reported concentration. The CH-B code is used to flag reported values which are below the calculated method detection limit for the sample. Such values are considered estimates only and should be used with discretion. CH-BB The reported concentration is below or equal to the detection limit. The detection limit is reported as a separate variable. CH-C The CH-C code indicates that the laboratory experienced minor deficiencies meeting the QC requirements, but the overall data quality is judged to be reliable for EMAP assessments. CH-CC Result may be affected by interference; an estimated concentration is reported. CH-D The CH-D code indicates that there was insufficient tissue in a given sample for analysis of all chemical components. In this case, only one or two groups of analytes were measured (usually metals or TBT). CH-DD User should decide MDL value. CH-E Estimated quantity below reported detection limit. CH-EE Concentration is undetectable and equal to or less than the detection limit; value set to 0; MDL may be listed; user may decide to use another value. CH-F Algae Present - Indicates that the presence of algae in the sample prevented accurate measurement of TOC. Samples with the CH-F code will have a missing value for TOC. CH-FF Evidence analyte present CH-G Blank Interference - Indicates that there was an interference detected in the blank which would interfere with the accurate determination of an analyte concentration. Results for observations with the CH-G code should be considered questionable and used with discretion. CH-GG Analyte not detected @ or above reported estimated result. CH-H Concentration is undetectable; user to decide regarding interpretation. CH-I Some analytes are difficult to quantify because they co-elute with other closely related analytes. This phenomenon is called matrix interference. When this occurs the suspect analyte(s) are given a CH-I code and concentration is left blank. CH-J Failed QA criteria. CH-JJ Exceeds Reference Value (ERV) control limits 30% for organics and 20% for metals. CH-K Below reporting level. CH-KK Questionable data. CH-L Some of the analytes listed represent the sum of concentrations of similar analytes (e.g. PCB_TOT is the sum of the concentrations of all PCB congeners). In the event that the concentrations for all of the individual analytes included in the sum are non-detects (have CH-A code) the sum is missing. This is not technically a non-detect, but a sum of non-detects. CH-LL Duplicate analysis not within control limits CH-M Indicates the sample required dilution prior to analysis. This has no effect on reported concentrations and is not a problem. Values with this code can be used with no further qualification. CH-N Field QA sample. CH-NN Matrix Interference CH-O Indicates that an analyte was detected in the sample, but at a concentration equal to or less than the method detection limit for the sample. In these cases, you can be confident that the analyte is present in the sample, but there is a high degree of uncertainty in the reported concentration. Therefore, these values should be considered estimates only, and used with discretion. CH-OO Accuracy not documented. CH-P Concentration is less than or equal to the MDL, but is detectable. CH-PP Concentration is estimated. CH-Q Indicates that the reported concentration is questionable due to interference from other compounds in the sample (matrix interference). Therefore, these values should be used with discretion. CH-R Indicates that the concentration of an analyte was too low to detect. The concentration is reported as 0. Although the actual concentration is unknown (but likely very low to none), reporting a concentration of 0 serves as a place holder. CH-S Not detected. CH-T Indicates cases where required quality assurance guidelines were not met by the lab. If no concentration is reported, then the QC problem was judged to be severe enough to invalidate the result for that analyte. If however a concentration is reported for an analyte with a CH-T code, then the overall data quality was judged to be reliable enough to be used with discretion. CH-U No QA/QC samples (i.e. Certified Reference Material) exist for evaluation of accuracy of this parameter. No apparent sample corruption was evident; caution is expressed for those who wish to convert to a dry weight basis. CH-V The reported concentration is considered an estimate because control limits for this analyte were exceeded in one or more quality control samples. CH-W In GC_ECD dual column confirmation results from the primary and secondary columns differed by more than a factor of 3. The lower of the two is reported. CH-X A laboratory may elect to cease reporting some analytes. EMAP protocol only requires that the laboratory analyze a given list of chemicals; when additional chemicals are analyzed and reported, they may be included in the data. The CH-X code indicates that an analyte has been excluded from a given set of data. only unflagged or CH-E coded values are considered valid and useful for most assessment purposes. CH-Y Below MDL (method detection limit). CH-Z Not analyzed QA Usage: Sediment toxicity test QA code QA Code QA code description ST-A More than 20 animals inoculated into replicate. ST-AA One lab replicate did not meet 90% survival rate required by QAPP. ST-B Fewer than 4 replicates were tested. ST-BB Estimated value. ST-C Fewer than 5 replicates were tested. ST-CC Questionable data. ST-D Mean control survival was <85 %. ST-DD Minor deviation in test conditions. ST-E Sample held for >30 days prior to testing. ST-EE Control performance criteria not met. ST-F Sediment too coarse to sieve through 0.5 mm mesh, therefore making it difficult to recover clams. ST-G EC50_MC is reported as maximum value possible; sample is non-toxic. ST-H The mean survival reported is questionable because the survival in one or more control replicates did not meet the QA requirement of >80% survival. ST-I Control survival in one replicate was <80%. ST-K <20 animals used per replicate. ST-M Reduced number of replicates. ST-N Minor deviation in test conditions. ST-O Control performance criteria not met. ST-P Folly River control sediment not used. Note that this occurred only once. Sediments from Breach Inlet were used. ST-Q Statistical analysis not run because the mean growth rate was >100% of the mean control growth rate. ST-R Unable to calculate an EC50 value for this sample due to an insignificant decrease in luminescence or an increase in luminescence (i.e., little or no toxic effects). ST-S Very high to complete mortality of clams in sample (i.e., sample is toxic). ST-U Samples were processed within 14 days of sampling. ST-V Sample held for > 10 days prior to testing. ST-X Calculated EC50 result was greater than the highest test concentration of 10%. Because the accuracy of an EC50 value above 10% is unknown, EC50 values greater that 10% have been reported as 10.000%. ST-Y Hit/Miss result could not be determined due to missing silt-clay data. QA Usage: Water quality QA code QA Code QA code description WQ-A Values estimated from another data source. WQ-AA Indicates that the concentration of an analyte was too low to detect. The concentration is reported as 0. Although the actual concentration is unknown (but likely very low to none), reporting a concentration of 0 serves as a place holder. WQ-B DO value possibly as much as 0.32 low. WQ-BB Concentrations calculated from volume reported on field data sheet. WQ-C DO value possibly as much as 0.54 low. WQ-CC The reported concentration is below or equal to the detection limit; an estimated concentration is reported. The detection limit may be reported. WQ-D DO value possibly as much as 0.85 low. WQ-DD Result may be affected by interference; an estimated concentration is reported. WQ-E DO value possibly as much as 1.3 low. WQ-EE Surface photosynthetically active radiation (PAR) readings were not recorded. WQ-F DO value possibly as much as 1.6 low. WQ-FF Fewer than four photosynthetically active radiation (PAR) readings recorded; possible diminished reliability of attenuation coefficient estimate. WQ-G DO value possibly as much as 1.5 low. WQ-GG Calculated attenuation coefficients less then zero (not valid); reported as zero. WQ-H Only surface measures taken, depth <1 m. WQ-I Depth values questionable. WQ-J Fluorescence off-scale. WQ-K Shallow station: surface and bottom values equal. Bottom file used for both. WQ-L One sample was collected mid-depth due to shallow water (<3m); measurement values were reported identically for both surface and bottom layers. WQ-M The calculated salinity range was -0.1 to 0.1 ppt. The value is reported as zero. WQ-N If the measured concentration is below the detection limit, zero is reported for the parameter and the detection limit for the parameter is reported. WQ-O Missing text value. WQ-P Not detected. WQ-Q At a shallow station (<3m), a single mid-depth measurement was taken or a single mid-depth sample was collected. Measurements are reported identically in both the surface and bottom layers. WQ-S Secchi disc hit the bottom; the reading may be inaccurate (the true Secchi depth may have been deeper). WQ-T Estimated concentration below reporting level. WQ-U Estimated concentration below method detection limit. WQ-V Estimated concentration. WQ-W Questionable data. WQ-X Not defined. WQ-Y Below reporting level. WQ-Z Below method detection limit. QA Usage: Trawl abundance/biomass QA code QA Code QA code description FT-A Abundance count based on calculation of aliquot. FT-B The species was present in the trawl, but not counted. FT-C The species group was not weighed. FT-D The species, taxon or group was weighed, but the weight was not detected at the minimum level of 0.1 kg; therefore, the group weighed less than 0.1 kg. QA Usage: Trawl acceptability QA code QA Code QA code description NC-A Trawl was marginally acceptable because its duration was less than the planned 10 min. These observations may not truly represent the demersal community at a station, and may result in underestimation of abundance or diversity for that trawl. Data from trawls should be used with discretion. NC-B Trawl was unacceptable due to reasons such as: trawl filled with algae, trawl twisted or not properly opened, large object caught in trawl, trawl fouled on bottom. These situations generally resulted in the trawl being aborted well before its planned duration. Due to the problems mentioned above, any observations flagged with the NC-B QC code should not be used in data analyses. NC-C Trawl or other capture mechanism used to collect tissue sample only. NC-D Trawl outside target duration range. NC-E Trawl unsuccessful. QA Usage: Benthic index QA code QA Code QA code description BI-A Salinity values used to calculate a benthic index are interpolated.