United States Environmental Protection Agency Environmental Monitoring and Support Laboratory Cincinnati OH 45268 Research and Development EPA/600/S4-85/070 Jan. 1986 SER& Project Summary EPA Method Study 31: Trace Metals by Atomic Absorption (Furnace Techniques) T. R. Copeland and J. P. Maney An interlaboratory study in which 10 laboratories participated was conduct- ed to provide precision and accuracy statements for the analysis of 18 metals by graphite furnace atomic absorption spectrometry. Samples were prepared and analyzed using procedures speci- fied in "Methods for Chemical Analysis of Water and Wastes." EPA 600/4- 797 020, U.S. Environmental Protec- tion Agency, Environmental Monitoring and Support Laboratory, Cincinnati, OH, March 1979. The study design was based on You- den's non-replicate design for collabo- rative tests of analytical methods. Three Youden pair samples of the test metals were spiked into six types of test waters and then analyzed. The test waters were three industrial effluents supplied by ERCO and three waters supplied by the subcontractor laboratories (laboratory pure water, finished drinking water, and surface water). The resulting data were statistically analyzed using the com- puter program entitled "Interlaboratory Method Validation Study" (IMVS). The statistical analyses included re- jection of outliers, estimation of mean recovery (accuracy), estimation of single- analyst and overall precisions, and tests for the effects of water type on accuracy and precision. This Project Summary was developed by EPA's Environmental Monitoring and Support Laboratory, Cincinnati. OH. to announce key findings of the research project that is fully documented in a separate report of the same title (see Project Report ordering information at back). Introduction The Safe Drinking Water Act (SDWA) and the National Pollutant Discharge Elimination System (NPDES) require that waters and waste be analyzed to deter- mine their chemical content. The EPA was given a mandate to prepare methods which would be approved for the analysis of parameters of concern listed by these laws and resulting regulations. The EPA staff of the Environmental Monitoring and Support Laboratory of Cincinnati, Ohio, provided the procedures for monitoring metal parameters in wastes and waters in the document entitled, "Methods for Chemical Analysis of Water and Wastes." The second edi- tion of this manual, which was published in March 1979, added atomic absorption furnace methods to quantitate lower levels of metal parameters than those determinable by the flame atomic absorp- tion methods specified in the first edition. Energy Resources Co. Inc. (ERCO) was contracted by EPA to conduct a method study to define the accuracy and precision of the atomic absorption furnace proce- dure for the following 18 trace metals: Aluminum Antimony Arsenic Barium Beryllium Cadmium Chromium Cobalt Copper Iron Lead (Method (Method (Method (Method (Method (Method (Method (Method (Method (Method (Method 202.2) 204.2) 206.2) 208.2) 210.2) 213.2) 218.2) 219.2) 220.2) 236.2) 239.2) ------- Manganese Nickel Selenium Silver Thallium Vanadium Zinc (Method (Method (Method (Method (Method (Method (Method 243.2) 249.2) 270.2) 272.2) 279.2) 286.2) 289.2) Ten laboratories were selected by ERCO for participating in the method study following their successful analysis of performance evaluation samples. These laboratories then collected drinking, sur- face, and laboratory pure waters while ERCO supplied them with three different types of industrial effluents. These waters and effluents were analyzed to determine background levels of the elements of interest and subsequently specified vol- umes of unknown metal concentrates were added and the samples reanalyzed. The added level of each metal was determined by difference. Youden's non-replicate collaborative test design was applied to 10 participating laboratories. Formal statistical tech- niques compatible with the Youden de- sign were used to identify outliers, est- imate the method's accuracy and preci- sion, and test for the effect of water type. The formal statistical analyses were carried out using U.S. EPA's IMVS com- puter program. Procedure The study consisted of two distinct analysis phases. Phase I involved the selection of participating laboratories. An EPA-supplied list of laboratories and previous ERCO experience were used to solicit interested laboratories. Based on prior experience of the laboratories in graphite furnace analysis; assurance of adequate facilities, instrumentation, and personnel to complete the analyses in a timely manner; and cost estimates, 12 laboratories were selected to receive two pre-award performance evaluation sam- ples. These samples contained acid solu- tions of eight of the 18 metals of interest in sealed glass ampules. These solutions were spiked into lab- oratory pure water supplied by the indi- vidual participating laboratories and an- alyzed by the graphite furnace atomic absorption procedures to be employed in the interlaboratory study. The analytical results were submitted to ERCO for evaluation. Based upon the individual laboratories' analytical results and the above criteria, 10 laboratories were selected for partic- ipation in the study. Phase II consisted of the actual inter- laboratory study. This study required the analysis of six different water matrices, spiked at six different concentrations (three Youden pairs) of all 18 analytes of interest. In addition, each participating laboratory performed an analysis of the six waters with no spiked compounds added. Each participating laboratory then issued a report of all results to ERCO. The final step in the study was the statistical analysis of all data by Battelle Memorial Laboratories using EPA's INVS system. Results and Discussion The object of this study was to char- acterize the performance of graphite furnace atomic absorption procedures in terms of accuracy, overall precision, single-analyst precision, and the effect of water types on accuracy and precision. Through the statistical analysis of 8,640 analytical values, estimates of accuracy and precision were made and expressed as regression equations, which are pre- sented in Table 1. Of all 8,640 analytical values, 23% were rejected as outliers. The accuracy of the methods is obtained by comparing the mean recovery to the true values of concentration. The range of accuracy values (expressed as a percent relative error) was from 0.13% to 17,720%. This wide range was very dependent upon the individual analyte with the highest error being for zinc. The overall standard deviation indicates the precision associated with the meas- urements generated by the 10 laborator- ies. The overall precision (expressed as a percent relative standard deviation) ranged from 0.55% to 171 %. The highest relative standard deviation (worst preci- sion) occurred for silver. Statistical comparisons of the effect of water type were performed on all an- alytes. These indicated a practical effect of water matrix on the accuracy and/or precision of the methods in the following cases: Arsenic in effluents 2 and 3 Beryllium in surface water Nickel in effluents 2 and 3 Selenium in effluents 1 and 3 Silver in effluent 2 and Thallium in surface water and effluent 2 Conclusions and Recommendations Statistically significant matrix effects were found for several methods. Accuracy and precision were, in general, poorest for the low concentration levels. Many laboratories could not achieve the recom- mended method detection limits. For several analytes accuracy and precision for the highest concentration levels were also poor, indicating that non-linearity might not have been detected by some analysts. Environmental contamination with Al, Fe, and Zn affected the accuracy and precision of these analyses. For four of the six waters, zinc had the highest percentage of data rejected. On average, 23% of the data were rejected. For individual laboratories, data rejection ranged from 12% to 36%. From all of the above it must be concluded that accurate and precise results may be obtained only by analysts thoroughly experienced in the use of graphite furnace methods. It is recommended that instrumental parameters such as graphite type, back- ground correction, sheath gas, and use of matrix modifiers be specified so that variability from these effects is minimized and separated from sample matrix effects. It is further recommended that more rigorous checks be made to determine if the method of standard additions is required for a particular analyte/matrix combination. ------- Table 1. EPA Method Study—Trace Metals by AA. Regression Equations for Accuracy and Precision for Compound 1 Water Type Aluminum Water Type Aluminum Applicable cone, range Lab pure water Single-analyst precision O verall precision Accuracy Drinking water Single-analyst precision Overall precision Accuracy Surface Water Single-analyst precision Overall precision Accuracy Water Type (28.00-125.OO; iig/L SR = 0.23X + 6.45 S = 0.42X+ 5.83 X = 0.70C +32.36 SR = 0.72X+21.97 S = 0.2SX + 14.45 X = 1.IOC+ 39.21 SR = 0.33X+ 5.29 S = O.SOX - 0.27 X = -0.34C + 33.60 Aluminum Applicable cone, range Lab pure water Single-analyst precision Overall precision Accuracy Effluent 3 Single-analyst precision Overall precision Accuracy Water Type (26.80-120.00) ug/L SR = 0.23X+ 6.21 S = 0.42X + 5.80 X = 0.70C + 31.13 SR - 0.24X+ 3.18 S = 0.14X +26.59 X = 1.03C +32.88 Aluminum Applicable cone, range Lab pure water Single-analyst precision Overall precision Accuracy Effluent 1 Single-analyst precision Overall precision Accuracy Water Type (11.00-58.301 mg/L SR = 0.36X - 2.87 S = 0.39X - 2.27 X = 0.85C + 1.87 SR = 0./6X + 0,88 S = 0.26X + 2.24 X = 1.12C- 2.89 Antimony Applicable cone, range Lab pure water Single-analyst precision Overall precision Accuracy Effluent 2 Single-analyst precision Overall precision Accuracy Water Type (0.46-2.18) mg/L SR - 0.39X- 0.14 S = 0.39X - 0.09 X = 0.85C + 0.08 SR = -0.04X + 0.76 S = 0.07X+ 0.18 X - 0.85C+ 0.12 Antimony Applicable cone, range Lab pure water Single-analyst precision Overall precis/on Accuracy Effluent 1 Single-analyst precision Overall precision Accuracy Effluent 2 Single-analyst precision Overall precision Accuracy Effluent 3 Single-analyst precision Overall precision Accuracy Water Type (10.50-230.00) ug/L SR = 0.14X+ 1.09 S = 0.40X + 0.88 X = 0.65C + 0.56 SR = 0.24X- 0.50 S = 0.17X + 3.89 X = 0.88C- 1.28 SR = 0.72X + 4.23 S = 0.09X + 9.56 X = 0.73C + 5.80 SR - 0.22X + 0.37 S = 0.33X + 0.87 X = 0.61C+ 0.31 Arsenic Applicable cone, range Lab pure water Single-analyst precision Overall precision Accuracy Drinking Water Single-analyst precision Overall precision Accuracy Surface water Single-analyst precision Overall precision Accuracy Water Type (11.00-240.00) ug/L SR = 0.23X + 0.02 5 = 0.34X + 0.86 X = O.SOC - 2.66 SR = 0.21 X- 0.14 S = 0.18X+ 0.73 X - 0.87C- 2.14 SR = 0.16X+ 0.14 S = O.2OX + 0.87 X = O.81C-0.97 Arsenic Applicable cone, range Lab pure water Single-analyst precision Overall precision Accuracy Effluent 1 Single-analyst precision Overall precision Accuracy 19.78-227.00) ug/L SR = 0.08X + 2.82 S = 0.17X+ 1.98 X = 1.02C+ 3.30 SR = 0.07X + 5.85 S = 0.15X+ 4.01 X = 1.15C + 8.87 Applicable cone, range Lab pure water Single-analyst precision Overall precision Accuracy Drinking Water Single-analyst precision O verall precision Accuracy 110.20-237.00) ug/L SR = 0./OX+ 0.70 5 = 0.//X+ 1.98 X = 0.52C + 0.63 SR = 0.06X + 1.96 S = 0.12X+ 1.49 X = 0.93C + 0.62 ------- Table 1. (Continued) Water Type Arsenic Water Type Arsenic Applicable cone, range Effluent 2 Single-analyst precision Overall precision Accuracy Effluents Single-analyst precision Overall precision Accuracy Water Type (9.78-227.00) fjg/L SR = 0.16X +0.97 S = 0.14X +3.70 X = 0.94C-0.68 SR = 0.07X + 0.53 S = 0.15X+2.56 X = 0.87C - 0.30 Barium Applicable cone, range Surface Water Single-analyst precision Overall precision Accuracy Water Type /10.20-237.00) ug/L SR = 0.09X + 0.80 S = 0.13X +2.75 X = 0.91C-1.29 Barium Applicable cone, range Lab pure water Single-analyst precision Overall precision Accuracy Effluent 1 Single-analyst precision Overall precision Accuracy Effluent 2 Single-analyst precision Overall precision Accuracy Effluent3 Single-analyst precision Overall precision Accuracy Water Type (56.50-418.00) ug/L SR = 0.12X +4.80 S = 0.36X-8.62 X = 0.84C + 83.77 SR = 0.19X +70.20 S = 0.27X + 32.68 X = 0.97C + 67.43 SR = 0.29X-13.14 S = 0.58X-27.91 X = 0.84C + 42.52 SR = 0.69X-39.17 S = 0.34X + 9.88 X - 0.24C + 65.63 Beryllium Applicable cone, range Lab pure water Single-analyst precision Overall precision Accuracy Drinking Water Single-analyst precision 0 verall precision Accuracy Surface water Single-analyst precision Overall precision Accuracy Water Type (59.10-437.00) ug/L SR = 0.15X - 1.72 S = 0.14X +75.63 X = 0.84C + 30.67 SR = 0.11X +2.22 S = 0.37X - 10.56 X = 0.92C + 36.50 SR - 0.20X-0.16 S = 0.28X + 7.58 X = 0.93C + 30.17 Beryllium Applicable cone, range Lab pure water Single-analyst precision Overall precision Accuracy Effluent 1 Single-analyst precision O verall precision Accuracy Effluent 2 Single-analyst precision Overall precision Accuracy Effluents Single-analyst precision Overall precision Accuracy Water Type 10.45-10.90) ug/L SR = 0.7 2X + 0.05 S = 0.29X + 0.05 X - 1.15C-0.25 SR = 0.07X + 0.10 S = 0.19X +0.20 X - 0.92C + 0.11 SR = 0.12X-0.05 S = 0.07X + 0.19 X = J.08C + 0.01 SR = 0.13X-0.00 S - 0.20X + 0.08 X = 0.92C - 0.03 Cadmium Applicable cone, range Lab pure water Single-analyst precision Overall precision Accuracy Drinking water Single-analyst precision Overall precision Accuracy Surface water Single-analyst precision Overall precision Accuracy Water Type 10.47-11.40) ug/L SR = 0.1 OX+ 0.08 S = 0.11X + 0.18 X = O.98C - 0.05 SR = 0.03X + 0.11 S = 0.14X +0.07 X = J.01C-0.07 SR = 0.7 OX+ 0.02 S = 0.29X-0.08 X = 0.90C + 0.10 Cadmium Applicable cone, range Lab pure water Single-analyst precision Overall precision Accuracy (0.43-12.00J fjg/L SR = 0.09X + 0.25 S = 0.17X + 0.20 X = 1.02C + 0.24 Applicable cone, range Lab pure water Single-analyst precision 0 verall precision Accuracy (0.45-12.50) ug/L SR = 0.1 OX+ 0.05 S = 0.27X-0.05 X = 0.95C + 0.09 ------- Table 1. (Continued) Water Type Cadmium Water Type Cadmium Applicable cone, range Effluent 1 Single-analyst precision Overall precision Accuracy Effluent 2 Single-analyst precision Overall precision Accuracy Effluent 3 Single-analyst precision Overall precision Accuracy Water Type (0.43-12.00) ug/L SR = 0.14X +0.42 S = 0.32X^0.15 X = 0.75C + 0.39 SR = 0.12X + 0.09 S = 0.23X + 0.07 X = 0.81C + 0.15 SR = 0.15X^0.04 S = 0.27X^0.14 X = 0.96C + O.JO Chromium Applicable cone, range Drinking water Single-analyst precision Overall precision Accuracy Surface water Single-analyst precision Overall precision Accuracy (0.45-12.50) ug/L Sft = 0.17X + 0.11 S = 0.26X^0.10 X = 0.92C + 0.24 Water Type SR = 0.22X-0.13 S = 0.38X^0.10 X = 1.04C + 0.15 Chromium Applicable cone, range Lab pure water Single-analyst precision Overall precision Accuracy Effluent 1 Single-analyst precision Overall precision Accuracy Effluent 2 Single-analyst precision Overall precision Accuracy Effluents Single-analyst precision Overall precision Accuracy Water Type (9.87-236.00) fjg/L SR = 0.18X^0.73 S = 0.20X + 1.14 X - 0.89C+O.1J SR = 0.14X^0,88 S = 0.21 X +3.87 X = 0.87C+7.09 SR = 0.17X-0.32 5 = 0.14X + 2.S5 X = 0.95C + 1.03 SR = O.oax + 0.28 S = 0.22X + 0.41 X = 0.92C - 0.68 Cobalt Applicable cone, range Lab pure water Single-analyst precision 0 verall precision Accuracy Drinking water Single-analyst precision Overall precision Accuracy Surface water Single-analyst precision Overall precision Accuracy Water Type (10.30-246.00) ug/L SR = 0.12X-0.41 S = 0.14X +0.35 X = 0.94C + 0.40 SR = 0.06X^2.73 S = 0.12X^4.14 X = /.OOC + 0.89 SR = 0.12X- 0.12 S - 0.26X - 0.04 X = 0.91 C +0.47 Cobalt Applicable cone, range Lab pure water Single-analyst precision Overall precision Accuracy Drinking water Single-analyst precision Overall precision Accuracy Surface water Single-analyst precision Overall precision Accuracy Water Type 129.70-420.00)/jg/L SR = 0.09X + 0.50 S = 0.25X - 2.99 X = 0.88C + 1.36 SR = O.J2X+ 1.60 S = 0.23X+ 1.24 X = 0.92C + 0.44 SR - 0.14X- 1.00 S = 0.18X-0.14 X = 0.92C + 2.07 Cobalt Applicable cone, range Lab pure water Single-analyst precision O verall precision Accuracy Effluent 1 Single-analyst precision Overall precision Accuracy Water Type (24.80-407.00) ug/L SR = 0.1IX + 0.02 S = 0.25*-2.69 X = 0.89C+ 1.11 SR = 0.16X +0.58 S = 0.20X-0.89 X - 0.88C + 4.50 Cobalt Applicable cone, range Lab pure water Single-analyst precision Overall precision Accuracy (21.10-461.00) ug/L SR = 0.09X + 0.03 S = 0.25X- 1.99 X = 0.89C + 0.25 Applicable cone, range Lab pure water Single-analyst precision O verall precision Accuracy (29.30-435.00) ug/L SR = 0.09X + 0.16 S - 0.25X-3.31 X - 0.88C + 1.32 ------- Table 1. (Continued) Water Type Cobalt Water Type Cobalt Applicable cone, range Effluent 2 Single-analyst precision O verall precision Accuracy Water Type Applicable cone, range (21. 10-461. 00) ijg/L SR = 0.09X^3.21 S = 0.73X + 1.76 X = 0.95C + 0.43 Copper (10.10-234.OO)/jg/L Applicable cone, range fffluent 3 Single-analyst precision Overall precision Accuracy Water Type Applicable cone, range (29.30-435.00} ng/L SR = 0.06X + 2.06 S = 0.1 5X + 1.28 X = 0.82C + 1.43 Copper (0.30-1 .67) mg/L Lab pure water Single-analyst precision Overall precision Accuracy Effluent 1 Single-analyst precision Overall precision Accuracy Effluent 3 Single-analyst precision O verall precision Accuracy SR = 0.07X + 4.37 S = 0.11X + 4.97 X = 0.92C-0.81 SR = 0.22X - 0.44 S = 0.21X+ 1.21 X = 0.96C-0.10 SR = 0.13X+ 1.95 S = 0.29X + 4.96 X = 0.81 C +0.42 Lab pure water Single-analyst precision 0 verall precision Accuracy Effluent 2 Single-analyst precision O verall precision Accuracy SR = 0.13X-0.02 S = 0.13X-0.00 X = 0.93C + 0.01 SR = 0.05X + 0.02 S = 0.13X +0.01 X = 1.02C - 0.07 Water Type Copper Applicable cone, range (10.60-245.00) fjg/L Lab pure water Single-analyst precision Overall precision Accuracy Drinking water Single-analyst precision Overall precision Accuracy Surface water Single-analyst precision Overall precision Accuracy SR = 0.22X - 0.46 S = 0.21 X+ 1.29 X = 0.96C-0.77 SR = 0.15X +2.63 S = 0.34X + 3.39 X = 0.91 C +6.09 SR = 0.06X+1.18 S = 0.18X +1.44 X = 1.00C - 0.26 Water Type Iron Water Type Iron Applicable cone, range (26.10-455.00) ng/L Applicable cone, range (25.00-435.00) /jg/L Lab pure water Single-analyst precision Overall precision Accuracy Drinking water Single-analyst precision Overall precision Accuracy Surface water Single-analyst precision Overall precision Accuracy SR = 0.30X+26.73 S = 0.35X + 73.23 X = 1.40C+11.73 SR = 0.30X + 7.06 S = 0.36X + 9./5 X = 1.20C + 70.35 SR = 0.35X - 3.95 S = 0.34X + 37.42 X = 1.IOC+ 96.38 Lab pure water Single-analyst precision Overall precision Accuracy Effluents Single-analyst precision Overall precision Accuracy SR - 0.30X + 25.23 S = 0.35X+ 12.73 X = 1.41C+ 11.24 SR = 0.23X+16.21 S = 0.31X + 31.14 X = 1.09C + 37.18 ------- Table 1. (Continued) Water Type Iron Water Type Iron Applicable cone, range Lab pure water Single-analyst precision Overall precision Accuracy Effluent 1 Single-analyst precision Overall precision Accuracy Water Type (1.03-S.59) mg/L SR = 0.04X^0.13 S = 0.05X + 0.27 X = 1.01C + O.07 SR = 0.28X + 0.04 S = 0.41X-0.13 X = 1.16C-0.25 Lead Applicable cone, range Lab pure water Single-analyst precision Overall precision Accuracy Effluent 2 Single-analyst precision 0 verall precision Accuracy Water Type (0.37-2.61) mg/L SR = 0.06X + 0.03 S = 0.07X + 0.08 X = 1.42C-0.17 SR = 0.18X-0.03 S = 0.22X-0.01 X = r.OOC + 0.04 Lead Applicable cone, range Lab pure water Single-analyst precision Overall precision Accuracy Effluent 1 Single-analyst precision Overall precision Accuracy Effluent 2 Single-analyst precision Overall precision Accuracy Effluent 3 Single-analyst precision Overall precision Accuracy (10.40-243.00) ug/L SR = 0.17X-0.88 S = 0.17X+1.36 X = 1.06C-2.26 SR = 0.22X-0.14 S = 0.23X-0.06 X = 0.81 C + 2.05 SR = 0.14X+ 1.00 S = 0.22X+1.40 X = 0.86C-2.12 SR = 0.22X^1.48 S - 0.34X^1.86 X = 0.70C+ 1.63 Applicable cone, range Lab pure water Single-analyst precision 0 verall precision Accuracy Drinking water Single-analyst precision 0 verall precision Accuracy Surface water Single-analyst precision Overall precision Accuracy (10.90-254.00) ug/L SR = 0.20X^0.42 S = 0.28X - 0.66 X = 0.83C + 1.35 SR - 0.07X + 1.39 S = 0.2 IX + 2.56 X - 0.85C + 0.50 SR = 0.19X^0.11 S - 0.18X +1.73 X - 0.92C - 0.96 Water Type Applicable cone, range Lab pure water Single-analyst precision O verall precis/on Accuracy Drinking water Single-analyst precision Overall precision Accuracy Manganese (0.44-1 4.80) ug/L SR S = X = SR S = X = = 0.27X + 0.31 0.44X + 0.48 1.00C+1.46 = 0.1 6X + 0.51 0.38X + 0.52 0.90C+ 1.38 Water Type Applicable cone, range Lab pure water Single-analyst precision Overall precision Accuracy Effluent 1 Single-analyst precision Overall precision Accuracy Manganese (91. 00-484.00) ug/L SR S = X - SR S = X = = 0.03X+11.34 O.O5X + 1 1.20 0.55C + 12.98 = 0.04X + 40.27 0.1 IX + 32.01 0.97C - 6.66 Surface water Single-analyst precision 0 verall precision Accuracy Water Type Manganese Water Type Manganese Applicable cone, range Lab pure water Single-analyst precision 0 verall precision Accuracy Effluent 2 Single-analyst precision Overall precision Accuracy (111.00-666.00) ug/L SR = 0.05X^8.13 S = 0.07X + 9.19 X = 0.93C + 9.38 SR = 0.26X + 3.47 S = 0.32X - 6.30 X = 0.78C-8.22 Applicable cone, range Lab pure water Single-analyst precision O verall precision Accuracy £ffluent3 Single-analyst precision Overall precision Accuracy (0.42-14.20) ug/L SR = 0.27X + 0.37 S = 0.43X + 0.47 X = 1.00C+1.40 SR = O.23X + 0.52 S = 0.48X - 0.28 X = 0.46C + 2.56 ------- Table 1. (Continued) Water Type Nickel Water Type Nickel Applicable cone, range Lab pure water Single-analyst precision Overall precision Accuracy Effluent 1 Single-analyst precision Overall precision Accuracy Effluent 2 Single-analyst precision Overall precision Accuracy Effluent 3 Single-analyst precision Overall precision Accuracy Water Type (26.20-461.00) ug/L SR = 0.17X +0.34 S - 0.26X + 1.89 X = 0.84C + 6.46 SR = 0.1 OX+ 3.46 S = 0.16X +4.72 X = 0.67C + 70.56 SR = 0.13X + 2.39 S = 0.24X + 5.60 X = O.S5C-4.74 SR = 0.04X + 1.88 S = 0.18X+ 9.11 X = 0.84C - 9.99 Selenium Applicable cone, range Lab pure water Single-analyst precision O verall precision Accuracy Drinking water Single-analyst precision Overall precision Accuracy Surface water Single-analyst precision Overall precision Accuracy Water Type (27.40-482.00) ug/L SR = 0.21 X-2.45 S = 0.23X + 1.98 X = 0.93C - 2.02 SR = 0.12X +4.43 S = 0.27X + 2.20 X = 0.81 C +0.75 SR = 0.1 OX+ 4.38 S = 0.16X +9.37 X = 0.81 C +2.47 Selenium Applicable cone, range Lab pure water Single-analyst precision Overall precision Accuracy Effluent 1 Single-analyst precision Overall precision Accuracy Effluent 2 Single-analyst precision Overall precision Accuracy Effluent 3 Single-analyst precision Overall precision Accuracy Water Type (10.00-235.00) ug/L SR = 0.06X + 0.65 S = 0.17X + 0.14 X = 0.93C - 0.20 SR = 0.05X + 3.19 S = 0.19X+ 1.76 X = 0.88C-2.45 SR = 0.1 IX+ 3.14 S = 0.19X + 2.78 X = 1.11C-2.78 SR - 0.17X +0.20 S = 0.40X + 2.55 X = 0.84C-2.14 Silver Applicable cone, range Lab pure water Single-analyst precision Overall precision Accuracy Drinking water Single-analyst precision Overall precision Accuracy Surface water Single-analyst precision Overall precision Accuracy Water Type (10.50-246.00) ug/L SR = 0.1 OX+ 0.50 S = 0.14X + 2.18 X = 0.98C + 1.28 SR = 0.05X + 2.23 S = 0.16X + 3.16 X = 1.07C + 0.19 SR = 0.15X +0.25 S = 0.17X+ 1.64 X = 1.00C-0.66 Silver Applicable cone, range Lab pure water Single-analyst precision Overall precision Accuracy Effluent 1 Single-analyst precision Overall precision Accuracy Effluent 2 Single-analyst precision Overall precision Accuracy Effluents Single-analyst precision Overall precision Accuracy (8.48-56.50) ug/L SR = 0.19X-0.95 S = 0.17X + 0.35 X = 0.79C + 2.78 SR = 0.06X + 0.78 S = 0.28X - 1.05 X = 0.90C + 0.96 SR = 0.28X+1.11 S = 0.65X + 0.26 X = 0.49C + 0.03 SR = 0.34X-2.10 S = 0.38X-1.06 X = 0.70C + 4.27 Applicable cone, range Lab pure water Single-analyst precision Overall precision Accuracy Drinking water Single-analyst precision Overall precision Accuracy Surface water Single-analyst precision Overall precision Accuracy (0.45-13.60) ug/L SR = 0.15X +0.03 S = 0.18X + 0.15 X = 0.96C + 0.17 SR = -0.02X + 0.77 S = 0.20X + 0.17 X = 0.82C + 0.81 SR = 0.1 OX-0.07 S = 0.56X + 0.06 X = 0.87C + 2.46 8 ------- Table 1. (Continued) Water Type Thallium Water Type Thallium Applicable cone, range Lab pure water Single-analyst precision Overall precision Accuracy Effluent 1 Single-analyst precision Overall precision Accuracy Effluent 2 Single-analyst precision Overall precision Accuracy Effluent 3 Single-analyst precision Overall precision Accuracy (10.00-241.00)ijg/L SR = 0.15X +0.03 S = 0.12X +0.96 X = 0.87C-1.24 SR = 0.09X + 0.41 S = 0.30X - 0.04 X = 0.76C- 1.12 SR = 0.16X-0.20 S = 0.14X+ 1.58 X = 0.62C- 1.06 SR = 0.06X + 0.00 S = 0.19X +0.33 X = 0.81 C-1.70 Applicable cone, range Lab pure water Single-analyst precision Overall precision Accuracy Drinking water Single-analyst precision Overall precision Accuracy Surface water Single-analyst precision Overall precision Accuracy (10.50-252.00)/jg/L SR = 0.06X + 0.41 S = 0.1 IX+ 0.13 X = 0.88C-0.10 SR = 0.09X-0.29 S = 0.26X- 1.14 X = 0.89C - 0.89 SR = 0.1 OX+ 0.02 S = 0.25X-0.14 X = 0.84C-1.15 Water type Vanadium Water type Vanadium Applicable cone, range Lab pure water Single-analyst precision Overall precision Accuracy Drinking water Single-analyst precision Overall precision Accuracy Surface water Single-analyst precision Overall precision Accuracy (151.00-982.00) fig/7. SR = 0.12X + 2.14 S = 0.53X-44.69 X = 0.75C +26.06 SR = 0.04X + 21.95 S = 0.18X + 14.92 X = 1.00C-14.73 SR = 0.1 SX-5.47 S = 0.15X +0.56 X = 0.96C- 11.91 Applicable cone, range Lab pure water Single-analyst precision Overall precision Accuracy Effluent 1 Single-analyst precision Overall precision Accuracy Effluent 2 Single-analyst precision Overall precision Accuracy (144.00-939.00)vg/L SR = 0.12X + 1.96 S = 0.53X-42.61 X = 0.75C +25.26 SR = 0.04X + 19.60 S = 0.24X + 4.39 X = 1.05C-7.45 SR = 0.13X+14.33 S = 0.11X+19.77 X = 0.94C-17.68 Water type Vanadium Applicable cone, range Lab pure water Single-analyst precision Overall precision Accuracy Effluent 3 Single-analyst precision O verall precision Accuracy (1.36-6.031 mg/L SR = 0.05X + 0.01 S = 0.1 IX-0.01 X = 0.96C + 0.04 SR = 0.12X- 0.04 S = 0.21X-0.13 X = 0.99C-0.18 Water type Zinc Water type Zinc Applicable cone, range Lab pure water Single-analyst precision Overall precision Accuracy (0.54-17.40) ug/L SR = 0.56X- 1.19 S = 1.03X-1.03 X = 2.93C+J.02 Applicable cone, range Lab pure water Single-analyst precision Overall precision Accuracy (1.31-6.41) mg/L SR = 0.24X + 0.04 S = 0.30X + 0.11 X = 1.18C-0.31 ------- Table 1. (Continued) Water type Zinc Water type Zinc Applicable cone, range Drinking water Single-analyst precision Overall precision Accuracy Surface water Single-analyst precision Overall precision Accuracy (0.54-17.40) fjg/L SR = 0.31 X + 6.80 S = 0.99X + 0.69 X = 1.29C+14.50 SR = 0.59X-5.51 S = 1.06X-0.04 X = 2.43C + 7.16 Applicable cone range Effluent 1 Single-analyst precision Overall precision Accuracy (1.31-6.41 jmg/L SR = 0.35X + O.J9 S = 0.69X + 0.10 X = 0.42C + 0.84 Water type Zinc Water type Zinc Applicable cone, range (24.60-189.00) ug/L X = Mean recovery. C = True value for the concentration. Applicable cone, range (0.51 -16.70) ug/L Lab pure water Single-analyst precision Overall precision Accuracy Effluent 2 Single-analyst precision Overall precision Accuracy SR = 0.24X+1.21 S = 0.31 X+ 1.45 X = 1. 11 C -2.76 SR = 0.86X- 19.95 S = 0.77X-3.46 X = 1.04C + 9.S8 Lab pure water Single-analyst precision O verall precision Accuracy Effluents Single-analyst precision Overall precision Accuracy SR S = X = = 0.56X-J.04 1.00X-0.63 2.93C + 0.86 1.27X- 11.00 8.83C + 54.05 T. R. Copeland and J. P. Maney are with ERCO, Cambridge, MA 02138. Edward L. Berg and Robert L. Graves are the EPA Project Officers (see below). The complete report, entitled "EPA Method Study 31: Trace Metals by Atomic Absorption (Furnace Techniques)," (Order No. PB 86-121 704/AS; Cost: $28.95, subject to change) will be available only from: National Technical Information Service 5285 Port Royal Road Springfield, VA 22161 Telephone: 703-487-4650 The EPA Project Officers can be contacted at: Environmental Monitoring and Support Laboratory U.S. Environmental Protection Agency Cincinnati, OH 45268 10 •&U. S. GOVERNMENT PRINTING OFFICE: 1986/646-116/20749 ------- ? 2f 3 c O o CD S «> (D CO 8 o = c 3 O - 3 S 0) = -• C Ol N> 0> 00 -D m C a — > fe I ------- |