MD Dept. of Natural Resources, Chesapeake Bay Mainstem Water Quality Monitoring 2017

QUALITY ASSURANCE/QUALITY CONTROL Maryland Department of Natural Resources followed specific procedures to ensure that the Mainstem component of the Chesapeake Bay Water Quality Monitoring Program design was properly implemented and managed with sufficient accuracy, precision and detection limits. Accuracy (closeness to the true value) of collected data was controlled and assured by proper use, calibration and maintenance of both field and laboratory equipment for the measurement of physical and chemical parameters. The procedures to control and assure the accuracy of field measurements involved the calibration of field instruments, the verification of calibrations, and equipment maintenance. Most of the details of how data acquired with YSI sondes were quality assured and quality controlled are described in the process description elements in the Lineage portion of this metadata record. Daily quality control checks, which included the running of blanks and standards, were used to control and assure laboratory accuracy. Accuracy of Chesapeake Biological Laboratory, Nutrient Analytical Services Laboratory (CBL NASL) results was also assessed through DNR's participation in the Chesapeake Bay Coordinated Split Sample Program (CSSP) a split sampling program in which five laboratories involved in Chesapeake Bay monitoring analyze the coordinated split samples. CSSP was established in June 1989 to establish a measure of comparability between sampling and analytical operations for water quality monitoring throughout the Chesapeake Bay and its tributaries. DNR followed the protocols in the Chesapeake Bay Coordinated Split Sample Program Implementation Guidelines (EPA 1991) and its revisions. Split samples were collected quarterly. Results were analyzed by appropriate statistical methods to determine if results differed significantly among labs. If a difference occurred, discussions began regarding techniques and potential methods changes to resolve discrepancies. ADDITIONAL COMMENTS January 2017: Water for both the surface and the 1.0 m samples at stations CB5.1 and CB3.3C was collected at the same depth. Pycnoclines were not evident at stations: CB5.3, CB5.2, CB5.1, CB4.3C, CB4.2C and CB3.3C. Therefore the above pycnocline and below pycnocline water samples were collected at 1/3 and 2/3 of total water column depth, respectively. February 2017: The absence of a pycnocline at stations CB4.4, CB5.1, CB5.2 and CB5.3, led to above pycnocline and below pycnocline water sample collections at 1/3 and 2/3 of total water column depth, at each station. Surface and 1m sonde readings were taken at the same depth at stations CB5.1 and CB5.2. March 2017: At station CB3.1, water for both the above pycnocline and the surface sample was collected from the same bottle. Scoping is a term used to describe situations when strong currents and or winds make it difficult to maintain the water quality data sonde at a depth long enough for readings to stabilize. Meter scoping was noted at station: CB4.3. A ship passed while samples were collected at station CB4.4. April 2017: A note in the station CB4.1 station log stated that surface conductivity changed 1500 micro Siemens/cm from start of sampling to end. The sampling vessel drifted out of depth at station CB4.3E and it was necessary to re-position in order to collect the above pycnocline sample water. Shortly prior to beginning sampling at station CB4.3C, a cargo ship passed nearby. Due to no pycnocline, above pycnocline and below pycnocline water samples were collected at 1/3 and 2/3 of the total water column depth, respectively, at station CB2.2. Conductivity readings, at 7 meters depth, at station CB3.1, scrolled from 2000 micro Siemens/cm to 6000 micro Siemens/cm. May 2017: Surface and 0.5m samples were collected at the same depth. Water for both the above pycnocline and the surface sample was collected from the same bottle at station CB5.3. Station CB4.1E surface conductivity changed 1500 micro Siemens/cm from start of sampling to end of sampling. The sample freezer door was not closing completely on the by the end of the second day of the survey due to excessive ice. Ice was chipped enough to allow the freezer door to close. Freezer samples were removed to the field office overnight. June 2017: The first June cruse was conducted June 6-8. Meter scoping was noted at stations: CB5.3, CB5.2, CB5.1, CB4.3E, CB4.1C and CB4.1E. The problem of meter scoping lessened at station CB4.4. The second June cruise was conducted June 26-28. Meter scoping was noted at stations CB4.3C, CB3.3C and CB3.1. Hydrogen sulfide odors were observed in bottom sample waters collected at stations CB5.1, CB4.4, CB4.3C, CB4.2C, CB4.1C and CB4.1E. A pycnocline was not evident at station CB2.2 and therefore, the above pycnocline and below pycnocline water samples were collected at 1/3 and 2/3 of total water column depth, respectively. A shift in conductivity results was seen after the below pycnocline sample at station CB5.3 was collected. July 2017: During the first July survey (July 10-12), hydrogen sulfide odors were noted in bottom and below pycnocline sample waters collected at stations CB4.2C, CB4.1C, CB4.1E and CB3.3C. Logs for stations CB4.1C and CB4.1E recorded meter scoping. No pycnocline was evident at station CB2.2. Therefore, station CB2.2 above pycnocline and below pycnocline water samples were collected at 1/3 and 2/3 of total water column depth, respectively. Second July 2017 cruise was water column sonde readings only (no nutrient samples were collected). August 2017: On the first survey (August 8-10), meter scoping was a challenge at stations CB5.3, CB5.2 and CB5.1. A slight odor of hydrogen sulfide was detected in the station CB3.3C bottom water sample. Conductivity instability at 11 meters was remarked at station CB5.3. During the second cruise (August 30 and 31), the water appeared red at station CB4.3W. Station CB5.3 bottom and below pycnocline samples were collected from the same bottle. Surface and above pycnocline samples were collected from a single bottle at station CB3.1. Due to pycnocline absence at station CB2.2, above pycnocline and below pycnocline water samples were collected at 1/3 and 2/3 of total water column depth, respectively. September 2017: Meter scoping was noted at stations CB4.3C, CB4.3E, CB4.2C and CB4.1C. Results of conductivity sensor post-calibration checks were 5.6 percent higher than the conductivity standard at the following stations: CB3.1, CB2.2, CB2.1 and CB1.1. October 2017: Pycnoclines were not extant at stations CB5.2, CB5.1, CB4.4, CB4.3C, CB4.3E, CB4.2C, CB4.1C, CB4.1E and CB3.3C. Therefore, at each station, above pycnocline and below pycnocline water samples were collected at 1/3 and 2/3 of total water column depth, respectively. November 2017: A change in surface conductivity from the beginning to the end of sampling at station CB2.2 was noted 1–Nov-2017 at station CB2.2. Absence of pycnoclines at station CB3.2 on 1–Nov-2017 and stations CB5.2, CB4.3C CB4.2C and CB4.1C on 17–Nov-2017 made it necessary to collect above and below pycnocline samples from 1/3 and 2/3 of total water column depth, respectively. At stations CB5.2 and CB4.2C, both surface and 1 meter water samples were collected from the same parcel of water. At station CB3.1 on 17-Nov-2017, above pycnocline and surface water samples were collected from the same bottle. When station CB1.1 was sampled on 17-Nov-2017, the data sonde hit bottom at 5 meters depth. At stations CB4.2C and CB4.1C, meter scoping was observed. The weight, on the instrument-bottle array, may have touched bottom at station CB4.2C. Rain preceded sampling at stations CB5.3, CB5.2, CB5.1 and CB4.4. December 2017: Pycnoclines were not evident at stations: CB5.2, CB5.1 and CB2.2. Therefore the above pycnocline and below pycnocline water samples were collected at 1/3 and 2/3 of total water column depth, respectively.