Table of lab and field QC. Calibration QC requirements for attended Hydrolab field measurements involve determination of post-deployment calibration drift for the parameters of interest (except temperature). Calibration drift is determined by measuring the check standard solution at the conclusion of the field measurements. This check must be done within 12 hours of the last field measurement. The post- deployment checks must be done in the same order used for initial calibration and must be done before any maintenance or calibrations are performed (Table 7). Table 7. Acceptance limits for post-deployment calibration checks. Parameter Calibration Drift Check Dissolved Oxygen ± 4 % Temperature Done annually only Conductivity ± 10 % pH ± 0.2 pH units QC for field measurements is typically limited to measuring precision by collection of replicate field measurements. Replicates are done at a minimum frequency of 5% of measurements or at a minimum, once per day. A field replicate is defined as a separate in-situ measurement made following all procedures typically done between individual samples. The probe would typically be removed from the water body then returned to the same depth and position used in the original measurement. Table 8 describes the acceptance limits for field replicates. Table 8. Acceptance limits for field replicates measurements. Parameter Duplicate Samples Dissolved Oxygen RPD ≤ 20% Temperature ± 0.3 °C Conductivity RPD ≤ 20% pH ± 0.2 pH units Data sets that do not meet the field QC acceptance limits may require that the field measurement data be flagged. Comments on field QC results should be included in the QA review. If samples are not collected by King County staff, contracted field sampling personnel must forward field notes and data to the Environmental Laboratory LPM for review. The QC samples that will be analyzed in association with chemical testing are summarized in Table 9. Table 9. Chemistry QC samples for water analysis. Parameter Blank Replicate2 Matrix Spike Blank Spike LCS4 / CS5 Surrogates Total Phosphorus 1 / Batch 1 / Batch 1 / Batch 1 / Batch 1 / Batch No Orthophosphate 1 / Batch 1 / Batch 1 / Batch 1 / Batch 1 / Batch No Total Nitrogen 1 / Batch 1 / Batch 1 / Batch 1 / Batch 1 / Batch No Nitrate-Nitrite 1 / Batch 1 / Batch 1 / Batch 1 / Batch 1 / Batch No Ammonia 1 / Batch 1 / Batch 1 / Batch 1 / Batch 1 / Batch No Chlorophyll-a 1 / Batch 1 / Batch No No 1 / Batch No Pheophytin a 1 / Batch 1 / Batch No No No No Metals 1 / Batch 1 / Batch 1 / Bat...
