SEPA United States Environmental Protection Agency Office of Research and Development Washington, DC 20460 EPA 600/R-95/072 May 1995 Plutonium in Water Performance Evaluation Study A Statistical Evaluation of the March 17, 1995 Data 0593RSD96 cov-072 ------- Plutonium in Water Performance Evaluation Study March 17, 1995 Environmental Protection Agency Environmental Monitoring Systems Laboratory Las Vegas, Nevada ------- UNITED STATES ENVIRONMENTAL PROTECTION AGENCY OFFICE OF RESEARCH AND DEVELOPMENT ENVIRONMENTAL MONITORING SYSTEMS LABORATORY-LAS VEGAS P.O. BOX 93478 LAS VEGAS, NEVADA 89193-3478 (702/798-2100) Dear Participant, Enclosed are the results of the Nuclear Radiation Assessment Division (EMSL-LV) Performance Evaluation Study for Plutonium in Water; March 17, 1995. The known value for each analysis was determined by gravimetric methods, checked by chemical analyses performed by EMSL-LV's Radiochemistry Laboratory, and compared to the participating laboratories' grand average. The expected precision, determined by the known value, was taken from 'Table 3. Laboratory Precision: One Standard Deviation Values and Control Limits for Various Analyses", which is based on data accumulated over the years by the Performance Evaluation Program, and can be found in the Environmental Radioactivity Performance Evaluation Studies Program and Radioactive Standards Distribution Program information brochure. Please take a few minutes to review this report and the analytical data your laboratory submitted to us. If there are any apparent discrepancies, please notify us immediately. We encourage you to make use of the computer-automated data-entry system that has been in place for some time now. As the number of participants increases, and it becomes unrealistic for us to receive results by mail or FAX, the computer system will be our only avenue for accepting data. If you have any questions or comments, please send a message via the data-entry system or contact George Dilbeck at 702/798-2104 or Patricia Honsa at 702/798-2141. Sincerely, George Dilbeck Chemist Radioanalysis Branch Enclosure ------- NOTICE This material has been funded wholly by the U.S. Environmental Protection Agency. It has been subject to the Agency's review, and has been approved for publication as an EPA document. ------- EMSL-LV Performance Evaluation: Plutonium in Water, 17-Mar-1995 1/7 The following pages consist of separate sections for each of the nuclides in this study with four parts per section. After the first, each part is separated from the next by a new page or a thick horizontal bar. The first page of each section is a statistical summary for the nuclide and starts with a statement of the known value, the control limits, and the warning limits. The warning limits are placed at two normalized standard deviations above and below the known value and the control limits are three normalized standard deviations above and below the known value. If you keep control charts, these values will be useful for anticipating problems with the accuracy of your analytical methods. The coin shaped pie chart at the top of the summary page shows the fate of all the samples sent out in number and percentage terms. The pie chart starts at the top and rotates clockwise. The first sector represents those participants who submitted analytical results within both the warning and control limits. The next sector represents those who are in the warning region but not out of control. The third sector represents those who are out of control, but have passed the outlier test. The fourth sector represents those who have failed the outlier test. The last sector represents those participants who have failed to respond properly. This is the case if no analytical results were returned, or less than three determinations were reported, or if the results were received too late. The reeding on the edge of the coin is spaced at one percent intervals, and the sector shading becomes darker as the data reliability decreases. Sectors with zero width are not shown. The table in the center shows a number of statistical quantities calculated from the submitted data based on the mean and median values in relation to the known value, both before and after outlier removal. The lower pie chart uses the same construction as the upper chart and shows the distribution of properly submitted data in terms of deviation from the known value divided into sectors representing one, two, three, and greater than three normalized standard deviations. The second part is an alphabetical listing, in lab-code order, of submitted data and several calculated quantities. An entry that is shaded has been rejected because of one of the reasons listed above or failure of the outlier test. The fifth and sixth columns are a measure of laboratory precision. The Range analysis is a normalized value that you may use to keep precision control charts. If this value is between 2.0 and 3.0, your analytical process precision is in the warning zone; if it exceeds 3.0 it is out of control. The eighth and ninth columns are the differences from the mean of all non-outliers and from the known value, respectively. A tag symbol may appear in the last column. Each page with tags has a symbol definition summary at the bottom. If there is no tag symbol, the data is within the control limits, but it may be in the warning zone. The third part is a three-column listing of result average, tag symbol, and lab-code in average order excluding those labs not responding properly. In this order, all outliers and out-of-control results appear at the top or bottom of the list. The last part is two bar chart displays showing frequency distributions of responding participants. The first chart places the known value at the center and a bar at each 0.2 unit of expected precision. The second chart places the mean of the reported measurements at the center and a bar at each 0.2 unit of standard deviation. In both cases, a bar includes those results within 0.1 unit up to the maximum of six. Any results more than six units from the center value are shown cumulatively by a shaded bar one past the sixth unit. If the central tendency of the known value distribution falls away from the center, an error in accuracy is indicated. If the distribution is broad, poor precision is indicated. The mean value distribution is similar but uses the average and standard deviation of reported results as its basis. ------- 2/7 EMSL-LV Performance Evaluation: Plutonium in Water, 17-Mar-1995 The Range Analysis(R + SR) is calculated from the range, mean range and standard error of the range values. The range is the difference between the maximum and minimum results for the laboratory. The mean range is calculated by multiplying the expected precision by 1.693(for three results). The standard error of the range is calculated by multiplying the mean range by 2.575(for three results), subtracting the mean range from this product, and dividing the result by 3. If the range is greater than the mean range, then the range analysis is calculated by subtracting the mean range from the range, dividing the result by the standard error of the range and adding 1. If the mean range is greater than or equal to the range, then the range analysis is calculated by dividing the range by the mean range. The normalized deviation of the mean from the grand average is calculated from the deviation of the mean from the grand average and the standard error of the mean values. The deviation of the mean from the grand average is calculated by subtracting the grand average from the average of the laboratory's three results. The standard error of the mean is calculated by dividing the expected precision by the square root of 3(the number of results). The normalized deviation of the mean from the grand average is calculated by dividing the deviation of the mean from the grand average by the standard error of the mean. The normalized deviation of the mean from the known value is calculated from the deviation of the mean from the known value and the standard error of the mean values. The deviation of the mean from the known value is calculated by subtracting the known value from the average of the laboratory's three results. The standard error of the mean is calculated by dividing the expected precision by the square root of 3(the number of results). The normalized deviation of the mean from the known value is calculated by dividing the deviation of the mean from the known value by the standard error of the mean. A complete explanation of the statistical calculations involved in the report may be found in the Environmental Radioactivity Performance Evaluation Studies Program information brochure [Draft Revision of EPA-600/4-81-004], available from George Dilbeck, EMSL-LV, 702/798-2104. ------- EMSL-LV Performance Evaluation: Plutonium in Water, 17-Mar-1995 3/7 Plutonium-239 Statistical Summary 91 Participants The known value of this nuclide is 11.1 pCi/1 with an expected precision of 1.1; the control limits are 9.2 to 13.0; the warning regions are 9.2 to 9.8 and 12.4 to 13.0 12(13.2 %) Failed to respond ~._ 6(6.6 %) Outliers ' 4(4.4 %) Out of control * but not an outlier Statistic . 66(72.5 %) Within all limits Respondents 3(3.3 %) In warning zone but within control Non-outliers Mean Std. Dev. Variance % Coef. of Var. % deviation of mean from known value Norm, de v. of mean from known value Median % deviation of median from known value Norm. dev. of median from known value 13.78 19.85 393.94 143.98 24.19 0.14 10.70 -3.60 -0.02 Grand Avg 10.61 0.69 0.47 6.49 -4.43 -0.71 10.67 -3.90 -0.63 1O(12.7 %) More than 3 norm. S.D 3(3.8 %) Between 2 and 3 norm. S.D. 2(53.2 %) Within 1 norm. S.D. of known value 24(30.4 %) Between 1 and 2 norm. S.D. ------- 4/7 EMSL-LV Performance Evaluation: Plutonium in Water, 17-Mar-1995 Plutonium-239 Lab A AH AT AZ BB BC BG BG BG BK BL BM BO CA CJ CK CM CO CQ CS CX D DO DT E EL FJ FU FZ GQ HP J JE JK > ~;'^i ''411*'' JS JY KH L LT M NH r *** ^jjpii ' NJ NK Res. 1 10.7 11.0 " ' , -' "' 10.7 9.8 11.2 9.6 11.1 10.2 9.7 10.7 10.5 10.8 11.7 10.0 11.7 10.4 10.6 11.0 10.9 10.8 10.1 11.7 10.7 10.9 8.8 10.4 - - '7&k * 11.0 ,; ^J&lp 8.0 10.4 13.7 11.1 tUl*-*A>*' * r't-f.*" 22;4/ 10.6 9.8 10.9 11.3 10.7 * * - ",'"' "": 11.0 f \ s T* '* j s "' ^i "" ^Vf ^ £ j\ * f ------- EMSL-LV Performance Evaluation: Plutonium-239 Lab OB 6k OS \t*mt ^ * JW PQ PW v ^-tlT wT^ f^rnm-^ QC QJ xv* ^ %{U QZ RF RL RR RV SC SD SF SI SM ss ST sx sz TD TE TH TI TL TQ 'T8 UE UN, UP VUW VB ' VC- VE VG VI VO - ^ ^'_-_ > ,VQ: W WG WI s 0 s Res. 1 v9.9 _ ,, ; _s ^o -,^ 10.4 V, /v ^ - ' w ~'.xs -v\ ' ^ / %-'*:*^v T " i^' -^ap:o ,x ^^\-^V;> *: - ^ ^ ' ^ \ * \*%<; *% "" "" v1- ' X ^ %s \,^' VC % ^ v; 9.4 '''> '''-- ^^ V- , .... ^,^vv "" \"\ 9.5 10.4 9.6 11.9 12.0 10.1 11.1 10.8 11.0 10.1 10.4 10.8 10.4 10.4 10.6 11.2 10.7 10.8 11.4 10.0 x--v£5i4-|s^-" ''''^nV" 5"' o;" ~ " "- "" -''"" 8.9 '_ , - s -x"i^ * ^ ,^' , JkLl T:\ " - ?; \-'<;>-"^ 11.0 11.8 11.1 10.3 ^w.*" ^ ^ <" ; , v;-" ;s *; s<-%>Vj,' 10.3 12.1 10.6 Res. 2 10.4 iT;^'"\ A 10.3 A^ '* '"'* ,o "" -,s ^ ^ vX : ; 166;0 "'-^^--^ w01 O A j " \ ^ v "" ,v^"-.^>'^\ ,-* w s 10.8 ""^ X^ v,^ "\T^-Vs %\ \ 10.3 9.2 9.6 10.9 11.8 10.8 13.1 10.9 10.2 9.6 9.7 10.1 10.9 10.1 11.7 11.3 11.0 10.9 9.7 10.1 "!, ~:Wg a* "r'ip-i %); '"' !~ V " 8.9 ^ s\« 'y 1 ..,. ^P-l ' "" --O " ^ ^ "* 10.7 11.9 10.5 12.8 ' vV> -.^ -;; , ^\v,s* 10.2 10.9 10.7 Res. 3 10.4 ,,v * x-; -\ 10.6 ^ ^^^^V^'x'^.* v\ '-. ""V * '^ 'Kv^^ ^y 173.0: -Xv y\\--^;-" %'°'-<\V "^ % "" \ ^^ *NV ^ "' «, ^ V* " % 7, '^ 9.2 v "v - x l^y^^ ^T-.'T /" 9.8 8.7 10.3 11.4 10.9 10.0 12.6 10.9 10.8 11.2 10.7 10.6 8.9 11.6 10.0 11.5 10.2 10.7 10.4 10.3 -'-^TlAfviiQ ' . r. ,/^-9 ~':;^48|fW,- 9.5 »<'s\^'-' V '-' ,1,_11;^ ' 11 ^ ss s \ \ 10.5 12.2 11.4 8.6 S v w ;. -.-.^ ^<;W ^ ^ y^X^^;:\ 9.8 11.5 10.8 No data submitted Insufficient data x = Exper. Sigma 0.29 ^Vtfv;--xxiv,'' 0.15 x "-.^ * ^^T ^ T*^1- s ^ «.^\ * -\x V\ X ^V N= ': - ;^;^ ir^v^^^^ %, 4% ^v^ o .X ^ %-. ^\x'\^ * .. 0.87 -. X"- v, * "* ; \ " - ^\" C ""\ "s *XS ;-" 0.40 0.87 0.40 0.50 0.59 0.44 1.04 0.06 0.42 0.82 0.51 0.36 1.04 0.79 0.86 0.15 0.40 0.10 0.85 0.15 \v'%; ,-Q\,i"Qx\"~ ,\'L'P-2?'', *-'-^;\{-C^- 0.35 Vs --- 0.35 ? -:'x »:-'>:- *s' -~ 0.25 0.21 0.46 2.11 , \ ^- ^ ^ ^ s ^ ^ ' : : : \ , , ' o i " ' 0.26 0.60 0.10 Plutonium in Water, 17-Mar-1995 Rnganal (R + SR) Average 0.268 j^-fy "-^j 0.161 s 's''o''V S ^^'C" ^ %^s\ i X .-. X*1 "" "" -. ^ . -^43t HX ^-,-,,- " " . - <*\ ^ % N \ >% * ^ s . 0 0.859 < \A* v\ 0.430 0.913 0.376 0.537 0.591 0.430 1.141 0.054 0.430 0.859 0.537 0.376 1.141 0.805 0.913 0.161 0.430 0.107 0.913 0.161 ^0-483 0.268 ^ :Y " ;% 0.322 - ,.' - 0.376 * v ,<' ,-v 0.268 0.215 0.483 3.391 * \ ^\ " ^ ,s--s>-\-~ "-'\ 0.268 0.644 0.107 10.23 r'£7j?'"^ 10.43 ' 1 ^Vv \xv V^j^^x" ^ ^ ; ^! *\t V^^fe'^S^ . ^ * x *j *ff% ' £t^y % ." s ffi f *** V 9 > "^^^v*^ * v % - % ^ s ^X "" \ * \t % f1"1- Jo ;>; ;,-^5; "\x-xt. i" - 9.80" ' * -.^ s ^ s V '\"-"" .^N *^*^ ^^ 9.87 9.43 9.83 11.40 11.57 10.30 12.27 10.87 10.67 10.30 10.27 10.50 10.07 10.70 10.77 11.33 10.63 10.80 10.50 10.13 -o !-"i l^TSf- rJIJll9:H. 1 ' . ' \ !>'-, , ^5;- 9.10 11 " s ^ w__ll. ------- 6/7 EMSL-LV Performance Evaluation: Plutonium in Water, 17-Mar-1995 1 Plutonium-239 Lab Res. 1 Res. Exper. Rng anal Normalized deviation 2 Res. 3 Sigma (R + SR) Average (grand-avg) (known) Tag Z 11.2 11.6 10.2 0.72 0.752 11.00 0.62 -0.16 Average Tag 7.30 x 8.80 U 8.90 H 9.10 li 9.10 U 9.43 9.53 9.80 9.83 9.83 9.87 10.00 10.07 10.07 10.10 10.10 10.13 10.17 10.17 10.23 10.23 10.27 10.30 10.30 10.30 10.33 % responding labs 10- ---- _--___ ° I ' -'4 s No data submitted 0 = Insufficient data Data sorted by Laboratory Average Lab PV JY EL UP HP RF D QJ BK RL QZ NJ SX BB W BM TQ BG BG OB CM SS SM sc BG CJ Average Tag Lab 10.43 OS 10.43 BL 10.47 J 10.50 TL 10.50 ST 10.57 VO 10.60 CX 10.60 AZ 10.63 TH 10.67 SI 10.67 FJ 10.67 CQ 10.70 WI 10.70 SZ 10.70 DT 10.70 CO 10.73 VE 10.73 KH 10.73 JS 10.77 TD 10.80 TI 10.80 LT 10.83 BO 10.87 SF 10.87 NK 10.97 UE Average Tag 10.97 10.97 11.00 11.00 11.00 11.03 11.07 11.10 11.23 11.23 11.23 11.30 11.33 11.40 11.47 11.47 11.50 11.57 11.83 11.87 11.97 12.27 14.73 x 16.57 x 21.73 x 81.60 x 172.67 x Freo^uency distribution I _ I . - ... - f.lllllllt.lll. ... 1 " f " 4 ' * Normalized deviation of the mean from the known value TAG SYMBOLS ft Above control x = Determined to be an outlier li = Below control Lab CS AH Z VI FZ CA VB E NH JK A BC TE RR L CK WG RV DO JE VG SD TS GQ JP FU PQ ,~1 +6 limit limit ------- EMSL-LV Performance Evaluation: Plutonium in Water, 17-Mar-1995 7/7 Plutonium-239 % responding labs Frequency distribution 10' - T. . -6 -4-2 0 +2-1-4 +6 Normalized deviation of the mean from the grand average ------- |