ort No. 892 Proficiency Testin Roun - Total Solids, Total Suspendedd Solids, Dissolved Solids - January 2015

Transcription

1 Repo ort No. 89 Waters Proficiency Testin ng Roun nd No Total Solids, Total Suspendedd Solids, Total Dissolved Solids - January 015 Acknowledgments PTA wishes to gratefully acknowledge the technical assistancee provided for this program by Dr M Buckley-Smith and Mrs R Ryan, Global Proficiency Ltd (New Zealand). Also our thanks go to Global Proficiency Ltd (New( Zealand) and to Global Proficiency Ptyy Ltd (Australia) for the supply and distribution of the t samples. Copyright Proficiency Testing Australia, 0155 PO Box 7507 SILVERWATER NSW 18, Australia SD

2 CONTENTS 1. Foreword Program Features and Design Statistical Format PTA and Technical Advisers' Comments Outlier Results Reference... 5 APPENDIX A Results and Data Analysis Total Solids... A1 Total Suspended Solids... A7 Total Dissolved Solids... A13 APPENDIX B Sample Homogeneity and Stability Homogeneity and Stability Testing... B1 APPENDIX C Documentation Instructions to Participants... C1 Method Codes... C3 Results Sheet... C4

3 1 1. Foreword This report summarises the results of a proficiency testing program on the determination of Total Solids, Total Suspended Solids and Total Dissolved Solids in waters. This is round 17 in a planned series of programs involving the analysis of chemical and physical parameters of waters. The exercise was conducted in October 014 by Proficiency Testing Australia (PTA). The main aim of the program was to assess laboratories abilities to competently perform the prescribed analyses. The Program Coordinator was Mrs D Mihaila and the Technical Advisers were Dr M Buckley-Smith and Mrs R Ryan, Global Proficiency Ltd (New Zealand). This report was authorised by Mrs F Watton, PTA Quality Business Development Manager.. Program Features and Design.1 Each laboratory was randomly allocated a unique code number for the program to ensure confidentiality of results. Reference to each laboratory in this report is by code number only. Please note that a number of laboratories reported more than one set of results and, therefore, their code numbers (with letter) could appear several times in the same data set.. Laboratories were provided with the "Instructions to Participants" and "Results Sheet" (see Appendix C). Laboratories were requested to perform the tests according to their routine methods..3 Participants were provided with two plastic vials (labelled PTA 1 and PTA ) containing water samples for the analysis of Total Solids, Total Suspended Solids and Total Dissolved Solids..4 A total of 58 laboratories received samples, comprising: - 4 Australian participants; and - 16 overseas participants, including: - Brunei Darussalam (1), Democratic Republic of Congo (1), Indonesia (3), Malaysia (1), New Zealand (1), Nigeria (), Papua New Guinea (), Qatar (1), Russia (1), Singapore (1), Thailand (1), Vietnam (1). Of these 58 laboratories, 3 were unable to submit results by the due date..5 Results (as reported by participants) with corresponding summary statistics (i.e. number of results, median, normalised interquartile range, uncertainty of the median, robust coefficient of variation, minimum, maximum and range) are presented in Appendix A (for each sample and for each of the analyses performed)..6 A robust statistical approach, using z-scores, was utilised to assess laboratories testing performance (see Section 3). Robust z-scores and ordered z-score relevant to each test are presented in Appendix A.

4 The document entitled Guide to Proficiency Testing Australia, 014 (reference [1]) defines the statistical terms and details the statistical procedures referred to in this report..7 A tabulated listing of laboratories (by code number) identified as having outlier results can be found on page 5..8 Prior to sample distribution, a number of randomly selected samples were analysed for homogeneity and stability. Based on the results of this testing (see Appendix B) it was considered that the samples utilised for this program were homogeneous and stable. As such, any results later identified as outliers could not be attributed to any notable sample variability. 3. Statistical Format For each test the following information is given: - a table of results and calculated z-scores; - a list of summary statistics; and - ordered z-score charts. 3.1 Outlier Results and Z-scores In order to assess laboratories testing performance, a robust statistical approach, using z-scores, was utilised. Z-scores give a measure of how far a result is from the consensus value (i.e. the median), and gives a "score" to each result relative to the other results in the group. A z-score with an absolute value less than or equal to.0 is considered to be satisfactory, whereas, a z-score with an absolute value greater than or equal to 3.0 is considered to be an outlier and is marked by the symbol. Laboratories are also encouraged to review results which have an absolute z-score value between.0 and 3.0 (i.e..0 < z-score < 3.0). These results are considered to be questionable results. Each determination was examined for outliers with all methods pooled. The table on page 5 summarises the outlier results detected. 3. Results Tables and Summary Statistics The tables in Appendix A contain the results returned by each laboratory, including the code number for the method used and the robust z-score calculated for each result. Results have been entered exactly as reported by participants. That is, laboratories which did not report results to the precision (i.e. number of decimal places) requested on the Results Sheet have not been rounded to the requested precision before being included in the statistical analysis.

5 3 A list of summary statistics appears at the bottom of each of the results tables and consists of: - No. of Results: the total number of results for that test/sample; - Median: the middle value of the results; - Normalised IQR: the normalised interquartile range of the results; - Uncertainty of the Median: a robust estimate of the standard deviation of the Median; - Robust CV: the robust coefficient of variation expressed as a percentage, i.e. 100 x Normalised IQR / Median; - Minimum: the lowest laboratory result; - Maximum: the highest laboratory result; and - Range: the difference between the Maximum and Minimum. The median is a measure of the centre of the data. The normalised IQR is a measure of the spread of the results. It is calculated by multiplying the interquartile range (IQR) by a correction factor, which converts the IQR to an estimate of the standard deviation. The IQR is the difference between the upper and lower quartiles (i.e. the values above and below which a quarter of the results lie, respectively). For normally distributed data, the uncertainty of the median is approximated by: = number of results. Please see reference [1] for further details on these robust summary statistics. 3.3 Ordered Z-score Charts The charts in Appendix A indicate each laboratory's robust z-score, in order of magnitude, marked with its laboratory code number. From these charts, each laboratory can readily compare its performance relative to the other laboratories. These charts contain solid lines at +3.0 and -3.0, so that outliers are clearly identifiable as those laboratories whose "bar" extends beyond these "cut-off" lines. The y-axis of these charts has been limited, so very large z-scores appear to extend beyond the chart boundary.

6 4 4. PTA and Technical Advisers Comments 4.1 Metrological Traceability and Measurement Uncertainty of Assigned Values Consensus values (median) derived from participants results are used in this program. These values are not metrologically traceable to an external reference. Sample preparation was undertaken according to Global Proficiency Ltd s Standard Operating Procedures to ensure samples were fit-for-purpose, homogeneous and stable. Solutions were stable and homogeneous, and medians obtained from this proficiency round were in consistent agreement with the expected levels (dope concentration), as shown in Table 1. The slight under recovery of Total Suspended Solids results and slight over recovery of Total Dissolved Solids is as expected, due to the particle size distribution in the artificial solids solution. As the assigned value for each analyte in this program is the median of the results submitted by the participants, the uncertainty of the median for each analyte has been calculated and is presented in Table 1 below. Table 1. Comparison of expected levels (dope concentration) and proficiency medians. The values of the calculated uncertainty of the median are also presented. Analyte Sample Dope Concentration (mg/l) Median (mg/l) Uncertainty of the Median (mg/l) Total Solids (TS) Total Suspended Solids (TSS) Total Dissolved Solids (TDS) PTA PTA PTA PTA PTA PTA Overall, the performance of participants in this round was good, with robust CVs below 7% for all analytes.

7 5 4. Analysis of Round 17 Results 4..1 Total Solids Table compares the Total Solids median and robust CV from this round to those obtained in previous PTA rounds. Table. Comparison of current round variability and proficiency median of Total Solids testing with the results of the previous two rounds. Median Round Sample Robust CV (%) Participants (mg/l) PTA This study PTA Report 830 Report 767 PTA PTA PTA PTA Bias / Accuracy The Total Solids testing was successfully performed, with satisfactory results ( zscore.0) ranging between mg/l for sample PTA 1 and mg/l for sample PTA. Out of 41 results submitted for sample PTA 1 and 4 results for sample PTA, two questionable results (.0 < z-score < 3.0) were reported for sample PTA 1 (laboratories 575 and 607) and four questionable results were reported for sample PTA (laboratories 10, 551, 563 and 575). Three outlier results ( z-score 3.0) were obtained for sample PTA 1, requiring follow-up action by laboratories 36b, 498 and 563. Four outlier results were obtained for sample PTA, requiring follow-up action by laboratories 310, 36b, 464 and 607. The Total Solids data set formed an approximately normal distribution with no substantial bias attributable to any one method (Figures 1 and ). The method APHA 540 B (Total Solids Dried at ºC - method code 1) was the most popular method choice for Total Solids analysis, being used by approximately 80% of participants for sample PTA 1 and 79% of participants for sample PTA. The close agreement between the dope concentration and the median obtained in the round (Dope PTA1 : 71mg/L, Median PTA1 : 75.0 mg/l and Dope PTA : 43mg/L, Median PTA : mg/l), gives good confidence in laboratories ability to get the right answer. The method APHA 540 B indicates that the most likely sources of error in this test include insufficient drying and the necessity for rapid weighing to obtain a consistent weight. APHA recommends to limit the sample to no more than 00 mg of residue in the dish, to avoid a water-trapping crust from forming, and carrying out a Method Blank at least once per day or every 0 samples, as a minimum. APHA also recommends that laboratories should randomly select samples to be analysed in duplicate, preparing each of the two samples independently (APHA 00 B).

8 6 Total Solids - Sample PTA APHA 540 B Calculation Other 14 Frequency Results (mg/l) Figure 1. Spread of results for Total Solids testing of sample PTA 1, with a median of 75.0 mg/l. Total Solids - Sample PTA APHA 540 B Calculation Other 14 Frequency Results (mg/l) Figure. Spread of results for Total Solids testing of sample PTA, with a median of mg/l.

9 7 Measurement Uncertainty (MU) The MU reported by participants can be seen in Figures 3 and 4. Out of 41 participants for sample PTA 1 and 4 participants for sample PTA, 30 (73% and 71%, respectively) submitted MU information. Several of the stated MUs did not accurately reflect the difference between the median and the participant s result for these proficiency samples. A t-test of all the results (outliers removed), indicated that the overall reproducibility for Total Solids testing was 75.0 ± 3.7 mg/l for sample PTA 1 and ± 38.4 mg/l for sample PTA (95% CI). Thus, a cluster of reported MUs would have been expected in the region of mg/l, however the majority of laboratories indicated that their MU was below 30 mg/l. Laboratories 38, 471, 498, 545, 551, 563 and 607 may wish to re-examine their MU calculations, as their result was further from the median than their stated MU for at least one of the samples tested, as shown in Figures 5 and 6. Total Solids ± MU - Sample PTA APHA 540 B Calculation Other 6 Frequency Measurement Uncertainty (mg/l) Figure 3. MU for Total Solids testing of sample PTA 1, as reported by participants, compared with 95% confidence interval for overall reproducibility, ± 3.7 mg/l in this round, shown as a dashed line.

10 8 Total Solids ± MU - Sample PTA 8 7 APHA 540 B Calculation Other 6 5 Frequency Measurement Uncertainty (mg/l) Figure 4. MU for Total Solids testing of sample PTA, as reported by participants, compared with 95% confidence interval for overall reproducibility, ± 38.4 mg/l in this round, shown as a dashed line.

11 9 Total Solids - Sample PTA 1 Results of sample PTA 1, including MU, compared to the median Total Solids - Sample PTA 1 Laboratory Code Result ± MU Median Uncertainty of the Median Figure 5. Total Solids - Results of sample PTA 1, including MU, compared to the median. Results (mg/l)

12 10 Total Solids - Sample PTA Results of sample PTA, including MU, compared to the median Total Solids - Sample PTA Laboratory Code Result ± MU Median Uncertainty of the Median Figure 6. Total Solids - Results of sample PTA, including MU, compared to the median. Results (mg/l)

13 Total Suspended Solids Table 3 compares the Total Suspended Solids median and robust CV from this round to those obtained in previous PTA rounds. Results for this round were very good. Table 3. Comparison of current round variability and proficiency median of Total Suspended Solids testing with the results of the previous two rounds. Median Round Sample Robust CV (%) Participants (mg/l) PTA This study PTA Report 830 Report 767 PTA PTA PTA PTA Bias / Accuracy The Total Suspended Solids testing was successfully performed, with satisfactory results ( z-score.0) ranging between mg/l for sample PTA 1 and mg/l for sample PTA. Out of 54 results submitted for sample PTA 1 and 55 results for sample PTA, five questionable results (.0 < z-score < 3.0) were reported for sample PTA 1 (laboratories 117, 37, 39, 34 and 410) and five questionable results were reported for sample PTA (laboratories 71, 410, 466, 553 and 596). Three outlier results ( z-score 3.0) were obtained for sample PTA 1, requiring follow-up action by laboratories 33a, 590 and 607. Four outlier results were obtained for sample PTA, requiring follow-up action by laboratories 33a, 517, 551 and 590. The Total Suspended Solids data set formed an approximately normal distribution with no substantial bias attributable to any one method (Figures 7 and 8). The method APHA 540 D (Total Suspended Solids Dried at ºC - method code 5) was the most popular method choice for Total Suspended Solids analysis, being used by approximately 96% of participants. The most commonly used brands of Glass Filters in the analysis of Solids were Whatman (0), Advantech (6), Millipore (5) and PALL (4). Other brands included Sartorius, Environmental Express ProWeigh, MicroScience, Filtech and Munktell. None of the brands were over-represented between laboratories which obtained outlier results. The nominal filter sizes used included 0.45 micron (8), 1.0 micron (4), 1. micron (7), 1.5 micron (4), 1.6 micron (1) and.0 micron (). There were no obvious trends observed, due to insufficient laboratories with outlier results reporting the filter pore sizes used (just the filter diameter). However, the larger nominal filter pore sizes may have contributed to low biasing Total Suspended Solids results. Laboratories with low bias may also wish to look at their sample preparation procedures to obtain a well mixed and homogeneous sample to filter and dry (see homogeneity section for manufacturing precision). The most likely sources of error for laboratories with high bias would be insufficient drying.

14 1 Total Suspended Solids - Sample PTA APHA 540 D Other 16 Frequency Results (mg/l) Figure 7. Spread of results for Total Suspended Solids testing of sample PTA 1, with a median of mg/l. Total Suspended Solids - Sample PTA 8 4 APHA 540 D Other 0 Frequency Results (mg/l) Figure 8. Spread of results for Total Suspended Solids testing of sample PTA, with a median of 8.00 mg/l.

15 13 Measurement Uncertainty (MU) The MU reported by participants can be seen in Figures 9 and % of participants submitted MU information for sample PTA 1 and 75% of participants for sample PTA. Quite a number of the stated MUs did not accurately reflect the difference between the median and the participant s result for these proficiency samples. Laboratories 37, 71, 310, 39, 334, 38, 410, 466, 499, 519, 551, 607 and 674 may wish to re-examine their MU calculations, as their result was further from the median than their stated MU at least for one of the samples tested, as shown in Figures 11 and 1 below. A t-test of all the results (outliers removed), indicated that the overall reproducibility for Total Suspended Solids testing was ± 8.71 mg/l (13%) for sample PTA 1 and 8.00 ± mg/l (13%) for sample PTA (95% CI). Thus, we would have expected a larger number of MUs clustered around mg/l for sample PTA 1 in Figure 9, and around mg/l for sample PTA in Figure 10. Laboratories are to be commended, as this reproducibility was less than the SD of 0% stated in Method APHA 540 D, using samples of similar concentration. Total Suspended Solids ± MU - Sample PTA APHA 540 D Other 7 6 Frequency Measurement Uncertainty (mg/l) Figure 9. MU for Total Suspended Solids testing of sample PTA 1, as reported by participants, compared with 95% confidence interval for overall reproducibility, ± 8.71 mg/l in this round, shown as a dashed line.

16 14 Total Suspended Solids ± MU - Sample PTA 1 10 APHA 540 D Other 8 Frequency Measurement Uncertainty (mg/l) Figure 10. MU for Total Suspended Solids testing of sample PTA, as reported by participants, compared with 95% confidence interval for overall reproducibility, ± mg/l in this round, shown as a dashed line.

17 15 Total Suspended Solids - Sample PTA 1 Results of sample PTA 1, including MU, compared to the median Total Suspended Solids - Sample PTA Laboratory Code Result ± MU Median Uncertainty of the Median Figure 11. Total Suspended Solids - Results of sample PTA 1, including MU, compared to the median. The outlier result of laboratory 607 is not shown. Results (mg/l)

18 16 Total Suspended Solids - Sample PTA Results of sample PTA, including MU, compared to the median Total Suspended Solids - Sample PTA Laboratory Code Result ± MU Median Uncertainty of the Median Figure 1. Total Suspended Solids - Results of sample PTA, including MU, compared to the median. The outlier result of laboratory 551 is not shown. Results (mg/l)

19 Total Dissolved Solids Table 4 compares the Total Dissolved Solids median and robust CV from this round to those obtained in previous PTA rounds. Table 4. Comparison of current round variability and proficiency median of Total Dissolved Solids testing with the results of the previous two rounds. Median Round Sample Robust CV (%) Participants (mg/l) PTA This study PTA Report 830 Report 767 PTA PTA PTA PTA Bias / Accuracy The Total Dissolved Solids testing was successfully performed, with satisfactory results ( z-score.0) ranging between mg/l for sample PTA 1 and mg/l for sample PTA. Out of 48 participants, three questionable results (.0 < z-score < 3.0) were reported for sample PTA 1 (laboratories 33a, 514 and 575) and three questionable results were reported for sample PTA (laboratories 41, 464 and 553). Four outlier results ( z-score 3.0) were obtained for sample PTA 1, requiring followup action by laboratories 117, 36b, 41 and 499. Two outlier results were obtained for sample PTA, requiring follow-up action by laboratories 36b and 499. The Total Dissolved Solids data set formed an approximately normal distribution with no substantial bias attributable to any one method (Figures 13 and 14). The method APHA 540 C (Total Dissolved Solids Dried at 180ºC - method code 8) was the most popular method choice for Total Dissolved Solids analysis, being used by approximately 88% of participants for sample PTA 1 and 85% of participants for sample PTA. As expected, laboratories which tended to low bias on their Total Suspended Solids results, high biased on their Total Dissolved Solids results, as their filters retained a smaller proportion of suspended solids, consequently overestimating the amount of dissolved solids in the sample.

20 18 Total Dissolved Solids - Sample PTA 1 0 APHA 540 C Calculation 16 Other Frequency Results (mg/l) Figure 13. Spread of results for Total Dissolved Solids testing of sample PTA 1, with a median of 08.0 mg/l. Total Dissolved Solids - Sample PTA APHA 540 C US EPA Calculation Other 10 Frequency Results (mg/l) Figure 14. Spread of results for Total Dissolved Solids testing of sample PTA, with a median of mg/l.

21 19 Measurement Uncertainty (MU) The MU reported by participants can be seen in Figures 15 and 16. Out of 48 participants, 36 (75%) submitted MU information. Many of the stated MUs did not accurately reflect the difference between the median and the participant s result for these proficiency samples. Laboratories 138, 38, 41, 471, 499, 545, 551 and 607 may wish to re-examine their MU calculations, as their result was further from the median than their stated MU at least for one of the samples tested, as shown in Figures 17 and 18 below. A t-test of all the results (outliers removed), indicated that the overall reproducibility for Total Dissolved Solids testing was 08.0 ± 8.0 mg/l (13%) for sample PTA 1 and ± 46.4 (13%) mg/l for sample PTA (95% CI). This was very close to the expected precision stated in APHA 540 C. Total Dissolved Solids ± MU - Sample PTA APHA 540 C Calculation Other 8 Frequency Measurement Uncertainty (mg/l) Figure 15. MU for Total Dissolved Solids testing of sample PTA 1, as reported by participants, compared with 95% confidence interval for overall reproducibility, ± 8.0 mg/l in this round, shown as a dashed line.

22 0 Total Dissolved Solids ± MU - Sample PTA APHA 540 C Calculation Other 6 Frequency Measurement Uncertainty (mg/l) Figure 16. MU for Total Dissolved Solids testing of sample PTA, as reported by participants, compared with 95% confidence interval for overall reproducibility, ± 46.4 mg/l in this round, shown as a dashed line.

23 1 Total Dissolved Solids - Sample PTA 1 Results of sample PTA 1, including MU, compared to the median Total Dissolved Solids - Sample PTA Laboratory Code Result ± MU Median Uncertainty of the Median Figure 17. Total Dissolved Solids - Results of sample PTA 1, including MU, compared to the median. Results (mg/l)

24 Total Dissolved Solids - Sample PTA Results of sample PTA, including MU, compared to the median Total Dissolved Solids - Sample PTA 634 Laboratory Code Result ± MU Median Uncertainty of the Median Figure 18. Total Dissolved Solids - Results of sample PTA, including MU, compared to the median. Results (mg/l)

25 3 4.3 Analysis of Results by Method Groups Further analysis of results by method groups was undertaken to provide specific information on individual method performance. In order for methods to be grouped for analysis, PTA requires at least 11 sets of results from the same method group. For methods other than those presented below, there were less than 11 results submitted for each method, therefore reliable conclusions cannot be drawn from analysing them separately on this occasion Total Solids The method APHA 540 B (Total Solids Dried at ºC - method code 1) was most frequently employed for Total Solids analysis. Out of 41 participants for sample PTA 1 and 4 participants for sample PTA, 33 laboratories (80% and 79%, respectively) indicated the use of this method. Table 5 below presents the median, uncertainty of the median and robust CV for Total Solids results obtained by this method in round 17. Table 5. Variability and proficiency medians of Total Solids results obtained by method APHA 540 B. Median ± Robust Analyte Sample Participants Uncertainty of the Median CV (%) (mg/l) Total Solids Total Suspended Solids PTA ± PTA ±.4.5 The method APHA 540 D (Total Suspended Solids Dried at ºC - method code 5) was most frequently employed for Total Suspended Solids analysis. Out of 54 participants for sample PTA 1 and 55 participants for sample PTA, 5 (96%) and 53 (96%) laboratories indicated the use of this method, respectively. Table 6 below presents the median, uncertainty of the median and robust CV for Total Suspended Solids results obtained by this method in round 17. Table 6. Variability and proficiency medians of Total Suspended Solids results obtained by method APHA 540 D. Median ± Robust Analyte Sample Participants Uncertainty of the Median CV (%) (mg/l) Total PTA ± Suspended Solids PTA ±

26 Total Dissolved Solids The method APHA 540 C (Total Dissolved Solids Dried at 180ºC - method code 8) was most frequently employed for Total Dissolved Solids analysis. Out of 48 participants, 4 (88%) and 41 (85%) indicated the use of this method for samples PTA 1 and PTA, respectively. Table 7 below presents the median, uncertainty of the median and robust CV for Total Suspended Solids results obtained by this method in round 17. Table 7. Variability and proficiency medians of Total Dissolved Solids results obtained by method APHA 540 C. Median ± Robust Analyte Sample Participants Uncertainty of the Median CV (%) (mg/l) Total PTA ± Suspended Solids PTA ±

27 5 5. Outlier Results Laboratories reporting results that have been identified as outliers are listed in Table 8 below. Table 8. Laboratory results identified as outliers for each analysis performed. Lab Code Total Solids Analysis Total Suspended Solids Total Dissolved Solids PTA 1 PTA PTA 1 PTA PTA 1 PTA a 36b Note: 1. A indicates the occurrence of a z-score outlier result (i.e. those results for which z-score 3.0). 6. Reference [1] Guide to Proficiency Testing Australia, 014 (This document can be found on the PTA website,

28 APPENDIX A Results and Data Analysis Total Solids... A1 Total Suspended Solids... A7 Total Dissolved Solids... A13

29 Total Solids Results Samples PTA 1 and PTA

30 A1 Total Solids Results by Laboratory Code Lab Code Result ± MU 1 (mg/l) Sample PTA 1 Robust z-score Method Code # # ± ± ± ± ± ± ± ± ± ± ± a 91 # ± # ± b 351 # ± ± ± ± # ± ± ± # ± ± ± # ± Where reported, results are shown with their corresponding measurement uncertainty (MU). " " denotes an outlier (i.e. those results for which z-score 3.0). Robust z-scores are calculated as: z = (A - median) normalised IQR, where A is the participant laboratory's result. 3 Please refer to Appendix C (page C3) for method code descriptions.

31 A Total Solids - cont. Results by Laboratory Code Lab Code Result ± MU 1 (mg/l) Sample PTA 1 Robust z-score Method Code ± # ± # # ± ± ± ± No of Results: 41 Median: 75.0 Normalised IQR: 17.0 Uncertainty of the Median: 3.3 Robust CV: 6.% Minimum: 4 Maximum: 370 Range: Where reported, results are shown with their corresponding measurement uncertainty (MU). " " denotes an outlier (i.e. those results for which z-score 3.0). Robust z-scores are calculated as: z = (A - median) normalised IQR, where A is the participant laboratory's result. 3 Please refer to Appendix C (page C3) for method code descriptions.

32 16 A3 Total Solids - Sample PTA Ordered Robust Z-Score Charts Total Solids - Sample PTA 1 - Robust Z-Scores lab code Robust Z-Scores lab code z-score z-score

33 A4 Total Solids Results by Laboratory Code Lab Code Result ± MU 1 (mg/l) Sample PTA Robust z-score Method Code # # ± ± ± ± ± ± ± ± ± ± ± a 445 # ± # ± a 430 # b 563 # ± ± ± ± # ± ± ± # ± ± ± # Where reported, results are shown with their corresponding measurement uncertainty (MU). " " denotes an outlier (i.e. those results for which z-score 3.0). Robust z-scores are calculated as: z = (A - median) normalised IQR, where A is the participant laboratory's result. 3 Please refer to Appendix C (page C3) for method code descriptions.

34 A5 Total Solids - cont. Results by Laboratory Code Lab Code Result ± MU 1 (mg/l) Sample PTA Robust z-score Method Code ± ± # ± # # ± ± ± ± No of Results: 4 Median: Normalised IQR: 17.4 Uncertainty of the Median: 3.4 Robust CV: 4.0% Minimum: 366 Maximum: 563 Range: Where reported, results are shown with their corresponding measurement uncertainty (MU). " " denotes an outlier (i.e. those results for which z-score 3.0). Robust z-scores are calculated as: z = (A - median) normalised IQR, where A is the participant laboratory's result. 3 Please refer to Appendix C (page C3) for method code descriptions.

35 545 A6 Total Solids - Sample PTA Ordered Robust Z-Score Charts Total Solids - Sample PTA - Robust Z-Scores lab code Robust Z-Scores a lab code z-score z-score

36 Total Suspended Solids Results Samples PTA 1 and PTA

37 A7 Total Suspended Solids Results by Laboratory Code Lab Code Result ± MU 1 (mg/l) Sample PTA 1 Robust z-score Method Code # ± # ± ± ± ± ± ± ± ± ± ± ± ± ± a 5.4 # ± ± # ± b 64 # ± ± ± ± ± ± # ± ± # Where reported, results are shown with their corresponding measurement uncertainty (MU). " " denotes an outlier (i.e. those results for which z-score 3.0). Robust z-scores are calculated as: z = (A - median) normalised IQR, where A is the participant laboratory's result. 3 Please refer to Appendix C (page C3) for method code descriptions.

38 A8 Total Suspended Solids - cont. Results by Laboratory Code Lab Code Result ± MU 1 (mg/l) Sample PTA 1 Robust z-score Method Code ± ± # ± # ± ± ± ± # ± ± # ± # # ± ± ± ± ± ± No of Results: 54 Median: Normalised IQR: 4.04 Uncertainty of the Median: 0.69 Robust CV: 6.1% Minimum: Maximum: 75 Range: Where reported, results are shown with their corresponding measurement uncertainty (MU). " " denotes an outlier (i.e. those results for which z-score 3.0). Robust z-scores are calculated as: z = (A - median) normalised IQR, where A is the participant laboratory's result. 3 Please refer to Appendix C (page C3) for method code descriptions.

39 A9 Total Suspended Solids - Sample PTA Ordered Robust Z-Score Charts Total Suspended Solids - Sample PTA 1 - Robust Z-Scores lab code Robust Z-Scores a b lab code z-score z-score

40 A10 Total Suspended Solids Results by Laboratory Code Lab Code Result ± MU 1 (mg/l) Sample PTA Robust z-score Method Code # ± # ± ± ± ± ± ± ± ± ± ± ± ± ± a 63.1 # ± ± # ± a 78.0 # b 79 # ± ± ± ± ± ± # ± ± Where reported, results are shown with their corresponding measurement uncertainty (MU). " " denotes an outlier (i.e. those results for which z-score 3.0). Robust z-scores are calculated as: z = (A - median) normalised IQR, where A is the participant laboratory's result. 3 Please refer to Appendix C (page C3) for method code descriptions.

41 A11 Total Suspended Solids - cont. Results by Laboratory Code Lab Code Result ± MU 1 (mg/l) Sample PTA Robust z-score Method Code # ± ± # ± # ± ± ± ± # ± ± # ± # # ± ± ± ± ± ± No of Results: 55 Median: 8.00 Normalised IQR: 5.19 Uncertainty of the Median: 0.88 Robust CV: 6.3% Minimum: 1.4 Maximum: 97.8 Range: Where reported, results are shown with their corresponding measurement uncertainty (MU). " " denotes an outlier (i.e. those results for which z-score 3.0). Robust z-scores are calculated as: z = (A - median) normalised IQR, where A is the participant laboratory's result. 3 Please refer to Appendix C (page C3) for method code descriptions.

42 A1 Total Suspended Solids - Sample PTA Ordered Robust Z-Score Charts Total Suspended Solids - Sample PTA - Robust Z-Scores lab code Robust Z-Scores a a b lab code z-score z-score

43 Total Dissolved Solids Results Samples PTA 1 and PTA

44 A13 Total Dissolved Solids Results by Laboratory Code Lab Code Result ± MU 1 (mg/l) Sample PTA 1 Robust z-score Method Code # # # ± ± ± ± ± ± ± ± ± ± ± a 38 # ± ± # ± b 87 # ± ± ± ± ± ± 8.8% # ± ± ± # ± Where reported, results are shown with their corresponding measurement uncertainty (MU). " " denotes an outlier (i.e. those results for which z-score 3.0). Robust z-scores are calculated as: z = (A - median) normalised IQR, where A is the participant laboratory's result. 3 Please refer to Appendix C (page C3) for method code descriptions.

45 A14 Total Dissolved Solids - cont. Results by Laboratory Code Lab Code Result ± MU 1 (mg/l) Sample PTA 1 Robust z-score Method Code ± ± ± ± # ± ± # ± # # ± ± ± ± ± No of Results: 48 Median: 08.0 Normalised IQR: 13. Uncertainty of the Median:.4 Robust CV: 6.3% Minimum: 180 Maximum: 87 Range: Where reported, results are shown with their corresponding measurement uncertainty (MU). " " denotes an outlier (i.e. those results for which z-score 3.0). Robust z-scores are calculated as: z = (A - median) normalised IQR, where A is the participant laboratory's result. 3 Please refer to Appendix C (page C3) for method code descriptions.

46 A15 Total Dissolved Solids - Sample PTA Ordered Robust Z-Score Charts Total Dissolved Solids - Sample PTA 1 - Robust Z-Scores Robust Z-Scores lab code lab code z-score z-score

47 A16 Total Dissolved Solids Results by Laboratory Code Lab Code Result ± MU 1 (mg/l) Sample PTA Robust z-score Method Code # # ± ± ± ± ± ± ± ± ± ± ± a 381 # ± ± # ± a 35 # b 484 # ± ± ± ± ± ± 8.8% # ± ± ± # ± Where reported, results are shown with their corresponding measurement uncertainty (MU). " " denotes an outlier (i.e. those results for which z-score 3.0). Robust z-scores are calculated as: z = (A - median) normalised IQR, where A is the participant laboratory's result. 3 Please refer to Appendix C (page C3) for method code descriptions.

48 A17 Total Dissolved Solids - cont. Results by Laboratory Code Lab Code Result ± MU 1 (mg/l) Sample PTA Robust z-score Method Code ± ± ± ± # ± ± # ± # # ± ± ± ± ± No of Results: 48 Median: Normalised IQR:.4 Uncertainty of the Median: 4.1 Robust CV: 6.3% Minimum: 90 Maximum: 484 Range: Where reported, results are shown with their corresponding measurement uncertainty (MU). " " denotes an outlier (i.e. those results for which z-score 3.0). Robust z-scores are calculated as: z = (A - median) normalised IQR, where A is the participant laboratory's result. 3 Please refer to Appendix C (page C3) for method code descriptions.

49 A18 Total Dissolved Solids - Sample PTA a Ordered Robust Z-Score Charts Total Dissolved Solids - Sample PTA - Robust Z-Scores Robust Z-Scores lab code lab code z-score z-score

50 APPENDIX B Sample Homogeneity and Stability Homogeneity and Stability Testing... B1

51 B1 Homogeneity and Stability Testing Samples for this program were obtained from Global Proficiency Ltd, New Zealand. As such, all samples are subjected to rigorous stability and homogeneity testing. A random selection of ten samples was chosen from samples PTA for homogeneity and stability testing. Seven of these were stored chilled and the remaining three were subjected to 35ºC for three days for an accelerated ageing stability trial. The samples were then analysed by Hill Laboratories, New Zealand. All stability samples showed no increased variability when compared to the chilled samples. Samples PTA 1 were also tested to confirm the levels were within the expected range. Three samples were randomly selected, stored chilled in the same conditions as the homogeneity samples and subjected to a verification testing (one replicate per sample) by Hill Laboratories, New Zealand. Homogeneity and stability characteristics were assumed to be similar to samples PTA, based on identical manufacturing procedure and sample handling. From statistical analyses based on the results of this testing and rigorous quality control, it was considered that all samples were sufficiently homogeneous and stable, so that any results later identified as outliers should not be attributed to any notable sample variability. The results of homogeneity and stability testing are presented in Tables B1 and B below. Please note that the mean results for these tests are not intended to be used as reference values. Table B1. Homogeneity and stability testing of PTA samples. Round PTA 17 Samples PTA (g/m 3 ) Sample ID Total Suspended Solids Total Dissolved Solids Total Solids Homogeneity H ± ± ± 70 H 81.0 ± ± ± 67 H ± ± ± 70 H ± ± ± 69 H ± ± ± 70 H ± ± ± 69 H ± ± ± 70 Stability S ± ± ± 67 S 81.0 ± ± ± 69 S ± ± ± 66 RSD.53% 3.06%.03% Table B. Confirmatory testing of PTA 1 samples. Round PTA 17 Samples PTA 1 (g/m 3 ) Sample ID Total Suspended Solids Total Dissolved Solids Total Solids Homogeneity H ± ± 8 66 ± 44 H 63.7 ± ± 6 6 ± 43 H ± ± 7 58 ± 4

52 APPENDIX C Documentation Instructions to Participants... C1 Method Codes... C3 Results Sheet... C4

53 C1 PROFICIENC CY TESTING AUSTRALIA WATERS PROFICIENCY TESTING PROGRAM CHEMICAL ANALYSIS ROUND 17 OCTOBER, 014 Total Solids (TS), Total Suspended Solids s (TSS), Total Dissolvedd Solids (TDS) INSTRUCTIOI ONS TO PARTICIPANTSS **Please record (on the Results Sheet) the approximate temperature of the samples upon receipt** Please note the following before commencingg the analysis of the samples. 1. Samples i) ii) iii) Two plastic vials labelled PTA 1 and PTA, supplied by Global Proficiency Ltd. The vials contain 0 ml of artificial wastee water concentrates for analysis of total solids, total suspendedd solids and total t dissolved solids Each vial will require dilution in reagent grade water. Please follow thee Sample Preparation section below. The vials must be thoroughly mixedd prior to analysis Please Note: Where possible, proficiency testing samples should s be treated as a routine laboratory sample.. Sample Preparation Note: The Residue sample colour is white. Caution: Analysis must begin immediately after vial is opened. i) ii) iii) iv) v) vi) vii) A separatee sample must be prepared from each vial. Adjust vial temperaturee to 0ºC. Add approximately 8000 ml of reagent grade water to a one-litre volumetric flask. Record vial ID number and mix thoroughly. Quantitatively transfer the entire contents from the vial intoo the flask, rinse the sides of the vial with reagent grade water and include this in the flask. Bring to volume with reagent grade water. Close the flask with a stopper and mix by inversion. viii) Repeat steps ii) vii) for second sample. Please report results for the diluted sample. SD

54 C 3. Tests Requested For the samples prepared from the two vials PTA 1 and PTA : i) Total Solids (TS). ii) Total Suspended Solids (TSS). iii) Total Dissolved Solids (TDS). (It is recommended that a reagent water blank is analysed by the same method used to analyse the samples.) If unable to perform the above please note this on your Results Sheet. 4. Safety i) Samples are for laboratory use only. ii) Participants should have sufficient experience and training to take the necessary precautions when handling the samples and reagent chemicals and during disposal. iii) Use of safety glasses, gloves, and fume hoods, where appropriate during the determinations, is recommended. 5. Reporting i) Report results using: Total Solids Total Suspended Solids Total Dissolved Solids ii) Report results in milligrams per litre (mg/l). iii) Do not correct results for recovery. zero decimal places one decimal place zero decimal places iv) In addition to reporting the results, record the method of analysis using the attached codes. v) Laboratories are also requested to calculate and report an estimate of measurement uncertainty (MU) for each reported measurement result. All estimates of MU must be given as a 95% confidence interval (coverage factor k ) and reported in mg/l. 6. Testing should commence as soon as possible after receiving the samples and results reported NO LATER THAN 14 NOVEMBER 014 to: Delfina Mihaila Proficiency Testing Australia PO Box 7507 SILVERWATER NSW 18 AUSTRALIA Phone: Fax: dmihaila@pta.asn.au 7. For this program your laboratory has been allocated the code number shown on the attached Results Sheet. All reference to your laboratory in reports associated with the program will be through this code number, thus ensuring the confidentiality of your results. 8. As a guide, ranges for the samples can be expected to be (in mg/l): Analyte Total Solids Total Suspended Solids Total Dissolved Solids Range mg/l mg/l mg/l

55 C3 Method Codes to be used for the Results Sheet ANALYSIS Total Solids Dried at C METHOD REFERENCE APHA SM US EPA METHOD DESCRIPTION CODE 540 B. Total Solids Dried at C Residue, Total Other Calculation: Suspended + Dissolved 3 Other (please specify) 4 Total Suspended Solids Dried at C APHA SM US EPA 540 D. Total Suspended Solids Dried at C Residue, Non-Filterable & Total Suspended Solids 5 6 Total Dissolved Solids Dried at 180 C Other APHA SM US EPA Other (please specify) C. Total Dissolved Solids Dried at 180 C Residue, Filterable 9 8 Other Calculation: Total Suspended 10 Other (please specify) 11 Method Reference Key i) APHA SM APHA Standard Methods for the Examination of Water and Wastewater (18, 19, 0, 1 and Edition). ii) USEPA U.S Environmental Protection Agency,

56 C4 PROFICIENC CY TESTING AUSTRALIA WATERS PROFICIENCY TESTING PROGRAM CHEMICAL ANALYSIS ROUND 17 Total Solids (TS), Total Suspended Solids (TSS), Total Dissolved D Solids (TDS) OCTOBER, 014 RESULTS SHEET (mg/l) Laboratory Code *Approximate temperature of samples uponn receipt: ANALYSISS Total Solids SAMPLEE PTA 1 Result (mg/l) ±MU (mg/l) SAMPLE PTA Result (mg/l) ±MUU (mg/l) METHOD CODE Dried at C Total Suspended Solids Dried at C Total Dissolved Solids Dried at 180 C Please state: Brand of filter used Nominal Filter size Please note: Where possible, proficiency testing samples should be b treated ass a routine laboratory sample. i) For each sample only a single result is requested. ii) Report results using: Total Solids zero decimal places Total Suspendedd Solids one decimal place Total Dissolved Solids zero decimal places.. iii) Report results in milligrams per litre (mg/l). iv) Do not correct results forr recovery. v) MU* Laboratories Measurement Uncertainty (MU) if knownn for the result. Please mg/l. report in DATE: SIGNATURE: INSTRUCTT WATERS PROF TEST PROG 17 SD Return results NO LATER THANN 14 NOVEMBER 014 to: Delfina Mihaila Proficiency Testing Australia PO Box 7507 Phone: SILVERWATER NSW 18 Fax: AUSTRALIA dmihaila@pta.asn.au