Tidal Water Quality Methods and QA - Chesapeake Bay Program

<body> <H4>Tidal Water Quality Methods and QA</H4><P>Maryland DNR and Virginia DEQ conduct water quality monitoring (link) in the mainstem and tidal tributaries of the Bay. Several institutions are involved in monitoring. DNR staff collect and process samples from Maryland tidal waters, which are then analyzed by the Nutrient Analytical Services Laboratory at the University of Maryland Chesapeake Biological Laboratory.</P><P>Virginia Chesapeake Bay samples are collected and analyzed by staff from the Water Quality Laboratory at Old Dominion University. Samples from Virginian tidal tributaries are collected and processed by Virginia Department of Environmental Quality staff and analyzed by the Division of Consolidated Laboratory Services. Participating Laboratories (pdf).<BR></P><H4>Analytical Methods</H4><P>In the 1980's, Bay Program scientists developed <A HREF="http://cbl.umces.edu/nasl/documents/np.pdf" TARGET="_top">laboratory methods</A> <IMG SRC="../images/pdf.gif" WIDTH="17" HEIGHT="16" ALT="PDF File"> to accurately detect low concentrations of nitrogen and phosphorus in seawater. Comparability studies showed that field filtering of nitrogen, phosphorus, and chlorophyll is necessary to prevent changes in concentration en route to the lab. Virginia and Maryland use the same field and laboratory methods. The <A HREF="../amqawg.htm" TARGET="_top">Analytical Methods and QA Workgroup</A> frequently compares laboratory procedures to ensure that method variability is minimized among laboratories. See Comparison of Methods and QA by Parameter and Laboratory (metmtrx99.wpd (pdf))</P><P>Methods are documented in several ways. Each institution has standard operating procedures that follow Chesapeake Bay Program Guidelines for Sampling and Analysis (pub EPA-903-R-96-006) (pdf). EPA's National Exposure Research Laboratories have validated many of the Chesapeake Bay Program Methods and published them in <A HREF="http://www.epa.gov/nerlcwww/ordmeth.htm" TARGET="_top">Methods for the Determination of Chemical Substances in Marine and Estuarine Environmental Matrices - 2nd Edition</A> (EPA/600/R-97/072). <BR></P><H4>Quality Control</H4><P>Field and laboratory staff introduce quality control samples into the sampling and analytical stream to check that procedures are performing properly. Blank, replicate and spiked samples measure the amount of bias and imprecision in the data. QC sample procedures and performance limits are specified in Chapter II, Sections D & E of Recommended Guidelines for Sampling and Analyses in the Chesapeake Bay Monitoring Program (pdf/publication), and in the Quality Assurance Project Plans. </P><H4>Detection Limits</H4><P>Method detection limit (MDL) values are calculated as 3 times the standard deviation of seven replicate measurements/analyses of the same sample. A calculated MDL may or may not be in the concentration range covered by the lowest calibration standard.</P><H4>Tidal Water Quality Data Analysis Methods</H4><UL><LI> Data Analysis Techniques for Status and Trends (pdf from Marcia Olson)</LI></UL><H4>Documentation </H4><UL><LI>Quality Assurance Project Plan for the Maryland Department of Natural Resources Chesapeake Bay Water Quality Monitoring ProgramChemical and Physical Properties Component for the period July 1, 1999 - June 30, 2000</LI><LI>Quality Assurance Project Plan for Virginia Chesapeake Bay Mainstem and Elizabeth River Water Quality Monitoring Program</LI><LI>Quality Assurance Project Plan for the Virginia Tidal Tributary Monitoring Program</LI><LI>Standard Operating Procedure for Elizabeth River Program Cruise Deployment</LI><LI>Standard Operating Procedure for Virginia Chesapeake Bay Program Cruise Deployment</LI><LI>Old Dominion University Laboratory Methods (pdf)</LI><LI><A HREF="http://cbl.umces.edu/nasl/documents/SOP.pdf" TARGET="_top">Chesapeake Biological Laboratory Nutrient Methods</A> <IMG SRC="../images/pdf.gif" WIDTH="17" HEIGHT="16" ALT="PDF File"><BR></LI></UL><H4>Publications (CBP)</H4><UL><LI>Recommended Guidelines for Sampling and Analyses in the Chesapeake Bay Monitoring Program (EPA-903-R-96-006) (pdf)</LI><LI>Chesapeake Bay Program Mainstem Coordinated Split Sample Program Report,1994-1998 (EPA-903-R-99-024)</LI><LI><A HREF="http://cbl.umces.edu/nasl/documents/np.pdf" TARGET="_top">Nitrogen and Phosphorus Determinations in Estuarine Waters: A Comparison of Methods Used in Chesapeake Bay Monitoring</A> (CBP/TRS 7/87) <IMG SRC="../images/pdf.gif" WIDTH="17" HEIGHT="16" ALT="PDF File"><BR> </LI></UL><table border="1" cellpadding="4" cellspacing="0" bgcolor="#C6C68C" width="100%"> <tr valign="top"> <td><strong>Other Sites of Interest:</strong><ul><li><A HREF="http://www.chesapeakebay.net/restrtn.htm" TARGET="_top">Chesapeake Bay Water Quality Monitoring </A>-</li><li><A HREF="http://www.chesapeakebay.net/restrtn.htm" TARGET="_top">Chesapeake Bay Monitoring </A>-</li><li><A HREF="http://www.cbl.umces.edu/nasl/index.html" TARGET="_top">CBL Nutrient Analytical Services Laboratory </A>-</li></ul></td></tr> </table><hr> <P ALIGN="CENTER"><a name="Ecosystem"></a><font face="Times New Roman" size="2">To bookmark this page, please use this URL: <a href="../qatidal.htm" target="_top">http://www.chesapeakebay.net/qatidal.htm</a></font></P><P ALIGN="CENTER"><font size="2">For more information, contact the Chesapeake Bay Program Office:<br> 410 Severn Avenue, Suite 109, Annapolis, MD 21403 / Tel: (800) YOUR-BAY / Fax: (410) 267-5777</font><font size="2">.</font></P><P ALIGN="CENTER"><font size="2"><a href="../termsofuse.htm" target="_top">Terms of Use</a> | <a href="../privacypolicy.htm" target="_top">Privacy Policy</a> | <a href="../comments.htm" target="_top">Contact Us<br> </a></font><font size="2"><a href="http://www.chesapeakebay.net/directions.htm" target="_top"> Directions to the Bay Program Office</a></font><br> <a href="http://www.chesapeakebay.net/cims" target="_top"><img src="../images/cims1.gif" height="19" width="51" border="0" align="left" vspace="10" alt="Chesapeake Information Management System (CIMS) "></a><a href="javascript:print()"><img src="../images/print.gif" width="31" height="38" border="0" alt="Print Current Page" align="right"></a><br> <font size="2">Last modified: 02/12/02</font></P></td><td align="left" valign="top" bgcolor="#E7E7D6">   </td></tr> <tr> <td align="left" valign="top" bgcolor="#E7E7D6"><img src="../images/endc3.gif" alt="endc3.gif (827 bytes)" WIDTH="8" HEIGHT="14"></td><td align="right" valign="top" bgcolor="#E7E7D6" colspan="2"><img src="../images/endd3.gif" alt="endd3.gif (827 bytes)" WIDTH="8" HEIGHT="14"></td></tr> </table></div>