US Geological Survey Quality Assurance Results Greg Wetherbee and Natalie Latysh

1. US Geological Survey Quality AssuranceResults Greg Wetherbee and Natalie Latysh NADP Spring Meeting March 23 - 24, 2004 Point Reyes National Seashore, CA

2. Interlaboratory Comparison Program Preliminary Results for 2003

3. Interlaboratory Comparison Program Quantify bias and precision of data produced by the CAL Compare performance of the CAL with other laboratories routinely analyzing low ionic strength samples

4. Participating Laboratories in the 2003 Interlaboratory Comparison Program • Illinois State Water Survey, Central Analytical Laboratory (CAL) • MACTEC, Inc. • Shepard Analytical Services (SA) • Meteorological Service of Canada (MSC) • Ontario Ministry of Environment & Energy (MOEE) • Acid Deposition and Oxidant Research Center (ADORC) • Norwegian Institute for Air Research (NILU) • New York State Department of Environmental Conservation Bureau • of Air Quality Surveillance (NYSDEC)

5. Samples used in the Interlaboratory Comparison Program during 2003 • Natural wet-deposition samples • NIST traceable synthetic precipitation samples • Ultrapure deionized-water samples

6. CAL’s Interlaboratory Comparison Study Results, 2003 CONTROL LIMITS WARNING

7. CAL’s Interlaboratory Comparison Study Results, 2003 CONTROL LIMITS WARNING

8. CAL’s Interlaboratory Comparison Study Results, 2003 CONTROL LIMITS WARNING

9. CAL’s Interlaboratory Comparison Study Results, 2003 CONTROL LIMITS WARNING

10. CAL’s Interlaboratory Comparison Study Results, 2003 CONTROL LIMITS WARNING Concentration Difference, in mg/L

11. CAL’s Interlaboratory Comparison Study Results, 2003 CONTROL LIMITS WARNING

12. CAL’s Interlaboratory Comparison Study Results, 2003 CONTROL LIMITS WARNING

13. CAL’s Interlaboratory Comparison Study Results, 2003 CONTROL LIMITS WARNING

14. CAL’s Interlaboratory Comparison Study Results, 2003 CONTROL LIMITS WARNING

15. CAL’s Interlaboratory Comparison Study Results, 2003 CONTROL LIMITS WARNING Concentration, in units

16. Number of Analyte Determinations Greater than the MDL for Ultrapure Deionized-Water Samples During 2003 N = Number of samples MDL = Method Detection Limit

17. Summary & Conclusions • CAL chemical analysis precision is comparable with other participating laboratories • CAL 2003 results are consistent with data from previous years • Laboratory contamination does not appear to be a problem for the CAL based on blank data • Quality of data appears to be acceptable for data users

18. Summary & Conclusions • Control charts show data outside of statistical control during 2003 for: Mg – May Na – February, August SO4 – September NH4 – January, February • Slight negative bias in results for: Ca, Mg, Na, NH4, pH • Slight positive bias in results for: Specific Conductance

19. Intersite Comparison Program 1998 - 2003

20. Intersite Comparison Program 1998 - 2003 • 11 intersite comparison • studies completed • QA solution pH range: • 4.08 - 5.06 • QA solution specific conductance • range: • 8.9 - 38.4 mS/cm • Proportion of successful • measurements: • ~90% for pH • ~95% for specific conductance

21. Intersite Comparison Program Percentage of Site Participants In Intersite Comparison Studies 98 PERCENT 84 1998 1999 2000 2001 2002 2003

22. Intersite Comparison Program Percentage of Successful pH and Specific Conductance Measurements 100 PERCENT 0 1998 1999 2000 2001 2002 2003

23. Intersite Comparison Program Percentage of Successful Follow up Re-Measurements 100 Follow up not conducted PERCENT 0 2000 1998 1999 2001 2002 2003

24. COMPARISON OF 2002 BLIND AUDIT AND 2003 SAMPLE HANDLING EVALUATION (SHE) RESULTS

25. 0.3 SHE Less Variability in Bucket – Bottle Differences for SHE than for Blind Audit 0 -0.2 BUCKET MINUS BOTTLE DIFFERENCES, IN mg/L 0.3 BLIND AUDIT 0 -0.2 Ca MgNaK NH4 Cl NO3SO4

26. 10 2002 BLIND AUDIT 0 BUCKET MINUS BOTTLE DIFFERENCES, IN mEq/L -10 10 2003 SHE 0 -10 57.54 mEq/L 2.51 Concentration

27. 5 2002 BLIND AUDIT 0 BUCKET MINUS BOTTLE DIFFERENCES, IN mS/cm -5 5 2003 SHE 0 1.5 Spec. Conductance 34.1 -5

28. BUCKET-BOTTLE CONCENTRATION DIFFERENCES In General: MRL >= SHE < BLIND AUDIT Median Concentration Differences

29. RELATIVE AND ABSOLUTE PERCENT DIFFERENCES = Median {100 * ([BUCKET]-[BOTTLE]) / ([BUCKET]+[BOTTLE]/2)}

30. DEIONIZED WATER BLANKS

31. CONCLUSIONS • LOWER VARIABILITY IN 2003 SHE DATA COMPARED TO 2002 BLIND AUDIT DATA • SHE MORE REPRESENTATIVE OF BIAS INTRODUCED BY SAMPLE HANDLING (LOWER LAB VARIABILITY) • ABSOLUTE ERROR INTRODUCED BY SAMPLE HANDLING IS LESS THAN MRL - NOT ENVIRONMENTALLY SIGNIFICANT TO DATA USERS

32. CONCLUSIONS • CONTACT OF SAMPLE WITH BUCKET APPEARS TO BUFFER HYDROGEN ION AND REDUCE CONDUCTIVITY • ACTUAL ENVIRONMENTAL pH IS SLIGHTLY LOWER THAN REPORTED BY NTN, AND ACTUAL ENVIRONMENTAL SPECIFIC CONDUCTANCE IS SLIGHTLY HIGHER THAN REPORTED BY NTN, SIMPLY DUE TO SAMPLE HANDLING

33. 2003 FIELD AUDITRESULTS

34. BUCKET-BOTTLE CONCENTRATION DIFFERENCES MRL >= Median Concentration Differences

35. = Median {100 * ([BUCKET]-[BOTTLE]) / ([BUCKET]+[BOTTLE]/2)}

36. DEIONIZED WATER BLANKS N = 18 NOTE: More hits for Field Audit blanks than SHE blanks

37. CONCLUSIONS • FIELD-AUDIT DATA INDICATE LOW-LEVEL SAMPLE CONTAMINATION - NOT ENVIRONMENTALLY SIGNIFICANT TO DATA USERS • FIELD EXPOSURE OF SAMPLE APPEARS TO BUFFER HYDROGEN ION AND REDUCE CONDUCTIVITY • ACTUAL ENVIRONMENTAL pH IS SLIGHTLY LOWER THAN REPORTED BY NTN, AND ACTUAL ENVIRONMENTAL SPECIFIC CONDUCTANCE IS SLIGHTLY HIGHER THAN REPORTED BY NTN, DUE TO FIELD EXPOSURE AND SAMPLE HANDLING

38. PROPORTION OF OVERALL ABSOLUTE ERROR FOR 2003

39. CONCLUSIONS • ABSOLUTE ERROR FOR NTN MEASUREMENTS IN 2003: (In General) 30 % SAMPLE HANDLING 20 % FIELD EXPOSURE 50 % SAMPLING EQUIPMENT + NATURAL VARIABILITY

40. CONCLUSIONS • SHE DOES NOT PROVIDE MUCH MORE INFORMATION THAN FIELD AUDIT • SHE PROGRAM WILL BE CANCELED IN JUNE 2004, AND FIELD AUDIT WILL EXPAND TO TEST ENTIRE NTN ANNUALLY STARTING 2005

41. USGS Collocated Sampler Program WATER YEAR 2003

42. Collocated sampler program Objectives • Detect changes in variability due to equipment and protocol changes • Compare overall system variability to components measured by other external quality assurance programs

43. Water Year 2003 Collocated Sites OK00– Salt Plains National Wildlife Refuge Operating Agency: U.S. Fish & Wildlife Service Initiated: 1983 WI98– Wildcat Mountain Operating Agency: Wisc. Dept. Nat. Resources Initiated: 1989

44. Collocated Sites WY 2003 CA99 NH02 and CO08

45. OK00 – Salt Plains National Wildlife Refuge

46. OK00 – Salt Plains National Wildlife Refuge

47. WI98 – Wildcat Mountain

48. WI98 – Wildcat Mountain

49. Median Absolute Differences for WY 2003 Collocated-Sampler Data

50. WY 2003 Summary • Overall error determined by the Collocated-Sampler Program during WY 2003 was comparable to results for previous years • Median relative error increased at WI98 between 2002 and 2003 for Na, K, and H-ion • Median absolute error < 15% for all constituents except: Ca, Na, NH4, Cl, and H-ion