Date: Fri, 19 Feb 1999 09:58:06 -0700 Subject: Trace Element News, v.2 From: Dennis Helsel To: nawqa_97pc@srv1rvares.er.usgs.gov, "Richard F Sanzolone, Denver, CO" , "Lawrence R Deweese, Fish and Wildlife Biologist, Denver, CO" Cc: "John S Zogorski, Supervisory Hydrologist, Rapid City, SD" , "Robert J Gilliom, Supv. Hydrologist, Sacramento, CA" , "Jeffrey D Stoner, Supervisory Hydrologist, Denver, CO" , "Carol A Couch, Hydrologist, Norcross, GA" , "Alan H Welch, Hydrologist, Carson City, NV" , "Peter C VanMetre, Project Chief, Hydrol(RGEG), Austin, TX" , "Lawrence R Deweese, Fish and Wildlife Biologist, Denver, CO" , "David P Krabbenhoft, Research Hydrologist (GeoChem), Middleton, WI" , "Edward Callender, Hydrologist, Reston, VA" , "Terry M Short, Physical Scientist, Menlo Park, CA" , "Michael T Koterba, Hydrologist, Baltimore, MD" , "Dennis A Wentz, Willamette NAWQA Chief, Portland, OR" , "Timothy L Miller, Chief, NAWQA, Reston, VA" , "William G Wilber, National Synthesis Coordinator, Reston, VA" , "Jeffrey T Armbruster, Asst. Reg. Hydr.-NAWQA, Norcross, GA" , "Michael C Yurewicz, Asst. Reg. Hydrol.-NAWQA, Reston, VA" , "Ivan C James II, Asst. Reg. Hydrologist-NAWQA, Denver, CO" , "Marc A Sylvester, Asst. Reg. Hydrologist-NAWQA, Menlo Park, CA" , "Dennis R Helsel, Hydrologist, Denver, CO" , "Glodt, Stephen R" Trace Elements in Bed Sediments The Geologic Division's lab, which analyzes the sediment samples NAWQA collects for trace elements, has made improvements and changes to their procedure. This has been done in full communication with NAWQA -- Rick Sanzalone (GD) is to be commended for keeping everyone informed, and working with us. The end result is a new bed sediment schedule. Information about this change follows: I. Schedule number II. Relating data across schedules III. Cost IV. Reporting Limits V. Sample Collection VI. Database I. Schedule Number The new schedule for trace elements in bed sediment is Schedule 2420. It replaced the old schedule 2400 as of two weeks ago. Use the new number for all samples submitted from now on. All bed sediment analyses for trace elements will now be run by schedule 2420, for NAWQA as well as for any other samples from WRD. The old schedule will no longer exist. II. Relating Data Across Schedules Most of the samples processed over the last 6 months were analyzed by both new and old procedures. QC comparisons were done for the two sets of methods. All 1994 study unit samples submitted had at least the old method performed, if not both, so that all samples were run by the same procedure as data collected earlier in their HIP. All 1997 study unit samples have had at least the new method performed, if not both, so all your samples will be run using the same (new) procedure. Comparison of results for samples run by both methods is being completed, will be published as an OFR, and available for people who will comparing data across the 91 through 97 study units. Based on early results, there is very little bias between the methods. The main difference is in the better precision and lower reporting limits for the new methods. III. Cost Cost for Schedule 2420 is $418.75, as compared to $512.90 for 2400 in FY98. Thats right -- the cost has now dropped 18%. This was effective as of two weeks ago. IV. Reporting Limits Below is a table which lists the elements and methods for both schedules, along with their reporting (minimum detection) limits (MDL). In short, reporting limits have dropped, sometimes dramatically (Au, Be, Ta). New Old New Old Element Sch 2420 Sch 2400 2420 MDL 2400 MDL ------- -------- -------- -------- -------- Al ICP-MS ICP-AES 0.005% 0.005% Ca ICP-MS ICP-AES 0.005% 0.005% Fe ICP-MS ICP-AES 0.005% 0.005% K ICP-MS ICP-AES 0.005% 0.05% Mg ICP-MS ICP-AES 0.005% 0.005% Na ICP-MS ICP-AES 0.005% 0.005% P ICP-MS ICP-AES 0.005% 0.005% Ti ICP-MS ICP-AES 0.005% 0.005% Ag ICP-MS AA 0.1 ppm 0.1 ppm As ICP-MS HGAA 0.1 ppm 0.1 ppm Au ICP-MS ICP-AES 1 ppm 8 ppm Ba ICP-MS ICP-AES 1 ppm 1 ppm Be ICP-MS ICP-AES 0.1 ppm 1 ppm Bi ICP-MS ICP-AES 1.0 ppm 10 ppm Cd ICP-MS AA 0.1 ppm 0.1 ppm Ce ICP-MS ICP-AES 1 ppm 4 ppm Co ICP-MS ICP-AES 1 ppm 1 ppm Cr ICP-MS ICP-AES 1 ppm 1 ppm Cu ICP-MS ICP-AES 1 ppm 1 ppm Eu ICP-MS ICP-AES 1 ppm 2 ppm Ga ICP-MS ICP-AES 1 ppm 4 ppm Ho ICP-MS ICP-AES 1 ppm 4 ppm La ICP-MS ICP-AES 1 ppm 2 ppm Li ICP-MS ICP-AES 1 ppm 2 ppm Mn ICP-MS ICP-AES 4 ppm 4 ppm Mo ICP-MS ICP-AES 0.5 ppm 2 ppm Nb ICP-MS ICP-AES 4 ppm 4 ppm Nd ICP-MS ICP-AES 1 ppm 4 ppm Ni ICP-MS ICP-AES 2 ppm 2 ppm Pb ICP-MS ICP-AES 1 ppm 4 ppm Sb ICP-MS HGAA 0.1 ppm 0.1 ppm Sc ICP-MS ICP-AES 2 ppm 2 ppm Sn ICP-MS ICP-AES 1 ppm 5 ppm Sr ICP-MS ICP-AES 2 ppm 2 ppm Ta ICP-MS ICP-AES 1 ppm 40 ppm Th ICP-MS DNA 1 ppm 1 ppm Tl ICP-MS not done 1 ppm none U ICP-MS DNA 0.1 ppm 0.1 ppm V ICP-MS ICP-AES 2 ppm 2 ppm Y ICP-MS ICP-AES 1 ppm 2 ppm Yb ICP-MS ICP-AES 1 ppm 1 ppm Zn ICP-MS ICP-AES 2 ppm 2 ppm CO3 C Titration Same 0.01% 0.01% Org C Total-CO3 C Same 0.01% 0.01% Tot C Combustion Same 0.01% 0.01% Tot S Combustion Same 0.05% 0.05% Hg CVAA Same 0.02 ppm 0.02 ppm Se HGAA Same 0.1 ppm 0.1 ppm V. Sample Collection With the new schedule, the lab now requires a minimum of only 5 grams of material (old requirement was 13 grams). This is another benefit of the new procedures. Two continuing concerns: Proper (wide-mouth) containers must be used. See Larry Shelton's field guide at http://water.wr.usgs.gov/pnsp/pest.rep/bs-t.html for details. Samples have been submitted in the wrong containers resulting in long drying times and possible contamination. Narrow neck bottles are the worst. It benefits all of us to get good data by using the right containers. Info on the ASRs must be filled out. If the site does not already have Lat-long (degrees, mins, secs), county and state location info in the computer database, these must be put onto the ASR. The lab must have these in order to identify samples. Not having it on the ASR or in the computer makes it very likely that the chemical info will be lost from the database, perhaps when you most need it. VI. Database If you are unsure about which procedure was used for the results stored for your samples, check the method code. ICP-MS will identify results from the new method. If you have any questions on these changes, call or email me. For lab or cost questions, contact Steve Glodt at the NWQL srglodt (303) 467-8021. --------------------------------------------------------------- Dennis R. Helsel Ph: (303) 236-2101 x227 U.S. Geological Survey Fax:(303) 236-4912 PO Box 25046, MS-415 Denver, CO 80225 dhelsel@usgs.gov